1 // SPDX-License-Identifier: (GPL-2.0+ OR BSD-3-Clause)
2 /*
3  * f_mass_storage.c -- Mass Storage USB Composite Function
4  *
5  * Copyright (C) 2003-2008 Alan Stern
6  * Copyright (C) 2009 Samsung Electronics
7  *                    Author: Michal Nazarewicz <mina86@mina86.com>
8  * All rights reserved.
9  */
10 
11 /*
12  * The Mass Storage Function acts as a USB Mass Storage device,
13  * appearing to the host as a disk drive or as a CD-ROM drive.  In
14  * addition to providing an example of a genuinely useful composite
15  * function for a USB device, it also illustrates a technique of
16  * double-buffering for increased throughput.
17  *
18  * For more information about MSF and in particular its module
19  * parameters and sysfs interface read the
20  * <Documentation/usb/mass-storage.rst> file.
21  */
22 
23 /*
24  * MSF is configured by specifying a fsg_config structure.  It has the
25  * following fields:
26  *
27  *	nluns		Number of LUNs function have (anywhere from 1
28  *				to FSG_MAX_LUNS).
29  *	luns		An array of LUN configuration values.  This
30  *				should be filled for each LUN that
31  *				function will include (ie. for "nluns"
32  *				LUNs).  Each element of the array has
33  *				the following fields:
34  *	->filename	The path to the backing file for the LUN.
35  *				Required if LUN is not marked as
36  *				removable.
37  *	->ro		Flag specifying access to the LUN shall be
38  *				read-only.  This is implied if CD-ROM
39  *				emulation is enabled as well as when
40  *				it was impossible to open "filename"
41  *				in R/W mode.
42  *	->removable	Flag specifying that LUN shall be indicated as
43  *				being removable.
44  *	->cdrom		Flag specifying that LUN shall be reported as
45  *				being a CD-ROM.
46  *	->nofua		Flag specifying that FUA flag in SCSI WRITE(10,12)
47  *				commands for this LUN shall be ignored.
48  *
49  *	vendor_name
50  *	product_name
51  *	release		Information used as a reply to INQUIRY
52  *				request.  To use default set to NULL,
53  *				NULL, 0xffff respectively.  The first
54  *				field should be 8 and the second 16
55  *				characters or less.
56  *
57  *	can_stall	Set to permit function to halt bulk endpoints.
58  *				Disabled on some USB devices known not
59  *				to work correctly.  You should set it
60  *				to true.
61  *
62  * If "removable" is not set for a LUN then a backing file must be
63  * specified.  If it is set, then NULL filename means the LUN's medium
64  * is not loaded (an empty string as "filename" in the fsg_config
65  * structure causes error).  The CD-ROM emulation includes a single
66  * data track and no audio tracks; hence there need be only one
67  * backing file per LUN.
68  *
69  * This function is heavily based on "File-backed Storage Gadget" by
70  * Alan Stern which in turn is heavily based on "Gadget Zero" by David
71  * Brownell.  The driver's SCSI command interface was based on the
72  * "Information technology - Small Computer System Interface - 2"
73  * document from X3T9.2 Project 375D, Revision 10L, 7-SEP-93,
74  * available at <http://www.t10.org/ftp/t10/drafts/s2/s2-r10l.pdf>.
75  * The single exception is opcode 0x23 (READ FORMAT CAPACITIES), which
76  * was based on the "Universal Serial Bus Mass Storage Class UFI
77  * Command Specification" document, Revision 1.0, December 14, 1998,
78  * available at
79  * <http://www.usb.org/developers/devclass_docs/usbmass-ufi10.pdf>.
80  */
81 
82 /*
83  *				Driver Design
84  *
85  * The MSF is fairly straightforward.  There is a main kernel
86  * thread that handles most of the work.  Interrupt routines field
87  * callbacks from the controller driver: bulk- and interrupt-request
88  * completion notifications, endpoint-0 events, and disconnect events.
89  * Completion events are passed to the main thread by wakeup calls.  Many
90  * ep0 requests are handled at interrupt time, but SetInterface,
91  * SetConfiguration, and device reset requests are forwarded to the
92  * thread in the form of "exceptions" using SIGUSR1 signals (since they
93  * should interrupt any ongoing file I/O operations).
94  *
95  * The thread's main routine implements the standard command/data/status
96  * parts of a SCSI interaction.  It and its subroutines are full of tests
97  * for pending signals/exceptions -- all this polling is necessary since
98  * the kernel has no setjmp/longjmp equivalents.  (Maybe this is an
99  * indication that the driver really wants to be running in userspace.)
100  * An important point is that so long as the thread is alive it keeps an
101  * open reference to the backing file.  This will prevent unmounting
102  * the backing file's underlying filesystem and could cause problems
103  * during system shutdown, for example.  To prevent such problems, the
104  * thread catches INT, TERM, and KILL signals and converts them into
105  * an EXIT exception.
106  *
107  * In normal operation the main thread is started during the gadget's
108  * fsg_bind() callback and stopped during fsg_unbind().  But it can
109  * also exit when it receives a signal, and there's no point leaving
110  * the gadget running when the thread is dead.  As of this moment, MSF
111  * provides no way to deregister the gadget when thread dies -- maybe
112  * a callback functions is needed.
113  *
114  * To provide maximum throughput, the driver uses a circular pipeline of
115  * buffer heads (struct fsg_buffhd).  In principle the pipeline can be
116  * arbitrarily long; in practice the benefits don't justify having more
117  * than 2 stages (i.e., double buffering).  But it helps to think of the
118  * pipeline as being a long one.  Each buffer head contains a bulk-in and
119  * a bulk-out request pointer (since the buffer can be used for both
120  * output and input -- directions always are given from the host's
121  * point of view) as well as a pointer to the buffer and various state
122  * variables.
123  *
124  * Use of the pipeline follows a simple protocol.  There is a variable
125  * (fsg->next_buffhd_to_fill) that points to the next buffer head to use.
126  * At any time that buffer head may still be in use from an earlier
127  * request, so each buffer head has a state variable indicating whether
128  * it is EMPTY, FULL, or BUSY.  Typical use involves waiting for the
129  * buffer head to be EMPTY, filling the buffer either by file I/O or by
130  * USB I/O (during which the buffer head is BUSY), and marking the buffer
131  * head FULL when the I/O is complete.  Then the buffer will be emptied
132  * (again possibly by USB I/O, during which it is marked BUSY) and
133  * finally marked EMPTY again (possibly by a completion routine).
134  *
135  * A module parameter tells the driver to avoid stalling the bulk
136  * endpoints wherever the transport specification allows.  This is
137  * necessary for some UDCs like the SuperH, which cannot reliably clear a
138  * halt on a bulk endpoint.  However, under certain circumstances the
139  * Bulk-only specification requires a stall.  In such cases the driver
140  * will halt the endpoint and set a flag indicating that it should clear
141  * the halt in software during the next device reset.  Hopefully this
142  * will permit everything to work correctly.  Furthermore, although the
143  * specification allows the bulk-out endpoint to halt when the host sends
144  * too much data, implementing this would cause an unavoidable race.
145  * The driver will always use the "no-stall" approach for OUT transfers.
146  *
147  * One subtle point concerns sending status-stage responses for ep0
148  * requests.  Some of these requests, such as device reset, can involve
149  * interrupting an ongoing file I/O operation, which might take an
150  * arbitrarily long time.  During that delay the host might give up on
151  * the original ep0 request and issue a new one.  When that happens the
152  * driver should not notify the host about completion of the original
153  * request, as the host will no longer be waiting for it.  So the driver
154  * assigns to each ep0 request a unique tag, and it keeps track of the
155  * tag value of the request associated with a long-running exception
156  * (device-reset, interface-change, or configuration-change).  When the
157  * exception handler is finished, the status-stage response is submitted
158  * only if the current ep0 request tag is equal to the exception request
159  * tag.  Thus only the most recently received ep0 request will get a
160  * status-stage response.
161  *
162  * Warning: This driver source file is too long.  It ought to be split up
163  * into a header file plus about 3 separate .c files, to handle the details
164  * of the Gadget, USB Mass Storage, and SCSI protocols.
165  */
166 
167 
168 /* #define VERBOSE_DEBUG */
169 /* #define DUMP_MSGS */
170 
171 #include <linux/blkdev.h>
172 #include <linux/completion.h>
173 #include <linux/dcache.h>
174 #include <linux/delay.h>
175 #include <linux/device.h>
176 #include <linux/fcntl.h>
177 #include <linux/file.h>
178 #include <linux/fs.h>
179 #include <linux/kstrtox.h>
180 #include <linux/kthread.h>
181 #include <linux/sched/signal.h>
182 #include <linux/limits.h>
183 #include <linux/pagemap.h>
184 #include <linux/rwsem.h>
185 #include <linux/slab.h>
186 #include <linux/spinlock.h>
187 #include <linux/string.h>
188 #include <linux/freezer.h>
189 #include <linux/module.h>
190 #include <linux/uaccess.h>
191 #include <asm/unaligned.h>
192 
193 #include <linux/usb/ch9.h>
194 #include <linux/usb/gadget.h>
195 #include <linux/usb/composite.h>
196 
197 #include <linux/nospec.h>
198 
199 #include "configfs.h"
200 
201 
202 /*------------------------------------------------------------------------*/
203 
204 #define FSG_DRIVER_DESC		"Mass Storage Function"
205 #define FSG_DRIVER_VERSION	"2009/09/11"
206 
207 static const char fsg_string_interface[] = "Mass Storage";
208 
209 #include "storage_common.h"
210 #include "f_mass_storage.h"
211 
212 /* Static strings, in UTF-8 (for simplicity we use only ASCII characters) */
213 static struct usb_string		fsg_strings[] = {
214 	{FSG_STRING_INTERFACE,		fsg_string_interface},
215 	{}
216 };
217 
218 static struct usb_gadget_strings	fsg_stringtab = {
219 	.language	= 0x0409,		/* en-us */
220 	.strings	= fsg_strings,
221 };
222 
223 static struct usb_gadget_strings *fsg_strings_array[] = {
224 	&fsg_stringtab,
225 	NULL,
226 };
227 
228 /*-------------------------------------------------------------------------*/
229 
230 struct fsg_dev;
231 struct fsg_common;
232 
233 /* Data shared by all the FSG instances. */
234 struct fsg_common {
235 	struct usb_gadget	*gadget;
236 	struct usb_composite_dev *cdev;
237 	struct fsg_dev		*fsg;
238 	wait_queue_head_t	io_wait;
239 	wait_queue_head_t	fsg_wait;
240 
241 	/* filesem protects: backing files in use */
242 	struct rw_semaphore	filesem;
243 
244 	/* lock protects: state and thread_task */
245 	spinlock_t		lock;
246 
247 	struct usb_ep		*ep0;		/* Copy of gadget->ep0 */
248 	struct usb_request	*ep0req;	/* Copy of cdev->req */
249 	unsigned int		ep0_req_tag;
250 
251 	struct fsg_buffhd	*next_buffhd_to_fill;
252 	struct fsg_buffhd	*next_buffhd_to_drain;
253 	struct fsg_buffhd	*buffhds;
254 	unsigned int		fsg_num_buffers;
255 
256 	int			cmnd_size;
257 	u8			cmnd[MAX_COMMAND_SIZE];
258 
259 	unsigned int		lun;
260 	struct fsg_lun		*luns[FSG_MAX_LUNS];
261 	struct fsg_lun		*curlun;
262 
263 	unsigned int		bulk_out_maxpacket;
264 	enum fsg_state		state;		/* For exception handling */
265 	unsigned int		exception_req_tag;
266 	void			*exception_arg;
267 
268 	enum data_direction	data_dir;
269 	u32			data_size;
270 	u32			data_size_from_cmnd;
271 	u32			tag;
272 	u32			residue;
273 	u32			usb_amount_left;
274 
275 	unsigned int		can_stall:1;
276 	unsigned int		free_storage_on_release:1;
277 	unsigned int		phase_error:1;
278 	unsigned int		short_packet_received:1;
279 	unsigned int		bad_lun_okay:1;
280 	unsigned int		running:1;
281 	unsigned int		sysfs:1;
282 
283 	struct completion	thread_notifier;
284 	struct task_struct	*thread_task;
285 
286 	/* Gadget's private data. */
287 	void			*private_data;
288 
289 	char inquiry_string[INQUIRY_STRING_LEN];
290 };
291 
292 struct fsg_dev {
293 	struct usb_function	function;
294 	struct usb_gadget	*gadget;	/* Copy of cdev->gadget */
295 	struct fsg_common	*common;
296 
297 	u16			interface_number;
298 
299 	unsigned int		bulk_in_enabled:1;
300 	unsigned int		bulk_out_enabled:1;
301 
302 	unsigned long		atomic_bitflags;
303 #define IGNORE_BULK_OUT		0
304 
305 	struct usb_ep		*bulk_in;
306 	struct usb_ep		*bulk_out;
307 };
308 
309 static inline int __fsg_is_set(struct fsg_common *common,
310 			       const char *func, unsigned line)
311 {
312 	if (common->fsg)
313 		return 1;
314 	ERROR(common, "common->fsg is NULL in %s at %u\n", func, line);
315 	WARN_ON(1);
316 	return 0;
317 }
318 
319 #define fsg_is_set(common) likely(__fsg_is_set(common, __func__, __LINE__))
320 
321 static inline struct fsg_dev *fsg_from_func(struct usb_function *f)
322 {
323 	return container_of(f, struct fsg_dev, function);
324 }
325 
326 static int exception_in_progress(struct fsg_common *common)
327 {
328 	return common->state > FSG_STATE_NORMAL;
329 }
330 
331 /* Make bulk-out requests be divisible by the maxpacket size */
332 static void set_bulk_out_req_length(struct fsg_common *common,
333 				    struct fsg_buffhd *bh, unsigned int length)
334 {
335 	unsigned int	rem;
336 
337 	bh->bulk_out_intended_length = length;
338 	rem = length % common->bulk_out_maxpacket;
339 	if (rem > 0)
340 		length += common->bulk_out_maxpacket - rem;
341 	bh->outreq->length = length;
342 }
343 
344 
345 /*-------------------------------------------------------------------------*/
346 
347 static int fsg_set_halt(struct fsg_dev *fsg, struct usb_ep *ep)
348 {
349 	const char	*name;
350 
351 	if (ep == fsg->bulk_in)
352 		name = "bulk-in";
353 	else if (ep == fsg->bulk_out)
354 		name = "bulk-out";
355 	else
356 		name = ep->name;
357 	DBG(fsg, "%s set halt\n", name);
358 	return usb_ep_set_halt(ep);
359 }
360 
361 
362 /*-------------------------------------------------------------------------*/
363 
364 /* These routines may be called in process context or in_irq */
365 
366 static void __raise_exception(struct fsg_common *common, enum fsg_state new_state,
367 			      void *arg)
368 {
369 	unsigned long		flags;
370 
371 	/*
372 	 * Do nothing if a higher-priority exception is already in progress.
373 	 * If a lower-or-equal priority exception is in progress, preempt it
374 	 * and notify the main thread by sending it a signal.
375 	 */
376 	spin_lock_irqsave(&common->lock, flags);
377 	if (common->state <= new_state) {
378 		common->exception_req_tag = common->ep0_req_tag;
379 		common->state = new_state;
380 		common->exception_arg = arg;
381 		if (common->thread_task)
382 			send_sig_info(SIGUSR1, SEND_SIG_PRIV,
383 				      common->thread_task);
384 	}
385 	spin_unlock_irqrestore(&common->lock, flags);
386 }
387 
388 static void raise_exception(struct fsg_common *common, enum fsg_state new_state)
389 {
390 	__raise_exception(common, new_state, NULL);
391 }
392 
393 /*-------------------------------------------------------------------------*/
394 
395 static int ep0_queue(struct fsg_common *common)
396 {
397 	int	rc;
398 
399 	rc = usb_ep_queue(common->ep0, common->ep0req, GFP_ATOMIC);
400 	common->ep0->driver_data = common;
401 	if (rc != 0 && rc != -ESHUTDOWN) {
402 		/* We can't do much more than wait for a reset */
403 		WARNING(common, "error in submission: %s --> %d\n",
404 			common->ep0->name, rc);
405 	}
406 	return rc;
407 }
408 
409 
410 /*-------------------------------------------------------------------------*/
411 
412 /* Completion handlers. These always run in_irq. */
413 
414 static void bulk_in_complete(struct usb_ep *ep, struct usb_request *req)
415 {
416 	struct fsg_common	*common = ep->driver_data;
417 	struct fsg_buffhd	*bh = req->context;
418 
419 	if (req->status || req->actual != req->length)
420 		DBG(common, "%s --> %d, %u/%u\n", __func__,
421 		    req->status, req->actual, req->length);
422 	if (req->status == -ECONNRESET)		/* Request was cancelled */
423 		usb_ep_fifo_flush(ep);
424 
425 	/* Synchronize with the smp_load_acquire() in sleep_thread() */
426 	smp_store_release(&bh->state, BUF_STATE_EMPTY);
427 	wake_up(&common->io_wait);
428 }
429 
430 static void bulk_out_complete(struct usb_ep *ep, struct usb_request *req)
431 {
432 	struct fsg_common	*common = ep->driver_data;
433 	struct fsg_buffhd	*bh = req->context;
434 
435 	dump_msg(common, "bulk-out", req->buf, req->actual);
436 	if (req->status || req->actual != bh->bulk_out_intended_length)
437 		DBG(common, "%s --> %d, %u/%u\n", __func__,
438 		    req->status, req->actual, bh->bulk_out_intended_length);
439 	if (req->status == -ECONNRESET)		/* Request was cancelled */
440 		usb_ep_fifo_flush(ep);
441 
442 	/* Synchronize with the smp_load_acquire() in sleep_thread() */
443 	smp_store_release(&bh->state, BUF_STATE_FULL);
444 	wake_up(&common->io_wait);
445 }
446 
447 static int _fsg_common_get_max_lun(struct fsg_common *common)
448 {
449 	int i = ARRAY_SIZE(common->luns) - 1;
450 
451 	while (i >= 0 && !common->luns[i])
452 		--i;
453 
454 	return i;
455 }
456 
457 static int fsg_setup(struct usb_function *f,
458 		     const struct usb_ctrlrequest *ctrl)
459 {
460 	struct fsg_dev		*fsg = fsg_from_func(f);
461 	struct usb_request	*req = fsg->common->ep0req;
462 	u16			w_index = le16_to_cpu(ctrl->wIndex);
463 	u16			w_value = le16_to_cpu(ctrl->wValue);
464 	u16			w_length = le16_to_cpu(ctrl->wLength);
465 
466 	if (!fsg_is_set(fsg->common))
467 		return -EOPNOTSUPP;
468 
469 	++fsg->common->ep0_req_tag;	/* Record arrival of a new request */
470 	req->context = NULL;
471 	req->length = 0;
472 	dump_msg(fsg, "ep0-setup", (u8 *) ctrl, sizeof(*ctrl));
473 
474 	switch (ctrl->bRequest) {
475 
476 	case US_BULK_RESET_REQUEST:
477 		if (ctrl->bRequestType !=
478 		    (USB_DIR_OUT | USB_TYPE_CLASS | USB_RECIP_INTERFACE))
479 			break;
480 		if (w_index != fsg->interface_number || w_value != 0 ||
481 				w_length != 0)
482 			return -EDOM;
483 
484 		/*
485 		 * Raise an exception to stop the current operation
486 		 * and reinitialize our state.
487 		 */
488 		DBG(fsg, "bulk reset request\n");
489 		raise_exception(fsg->common, FSG_STATE_PROTOCOL_RESET);
490 		return USB_GADGET_DELAYED_STATUS;
491 
492 	case US_BULK_GET_MAX_LUN:
493 		if (ctrl->bRequestType !=
494 		    (USB_DIR_IN | USB_TYPE_CLASS | USB_RECIP_INTERFACE))
495 			break;
496 		if (w_index != fsg->interface_number || w_value != 0 ||
497 				w_length != 1)
498 			return -EDOM;
499 		VDBG(fsg, "get max LUN\n");
500 		*(u8 *)req->buf = _fsg_common_get_max_lun(fsg->common);
501 
502 		/* Respond with data/status */
503 		req->length = min((u16)1, w_length);
504 		return ep0_queue(fsg->common);
505 	}
506 
507 	VDBG(fsg,
508 	     "unknown class-specific control req %02x.%02x v%04x i%04x l%u\n",
509 	     ctrl->bRequestType, ctrl->bRequest,
510 	     le16_to_cpu(ctrl->wValue), w_index, w_length);
511 	return -EOPNOTSUPP;
512 }
513 
514 
515 /*-------------------------------------------------------------------------*/
516 
517 /* All the following routines run in process context */
518 
519 /* Use this for bulk or interrupt transfers, not ep0 */
520 static int start_transfer(struct fsg_dev *fsg, struct usb_ep *ep,
521 			   struct usb_request *req)
522 {
523 	int	rc;
524 
525 	if (ep == fsg->bulk_in)
526 		dump_msg(fsg, "bulk-in", req->buf, req->length);
527 
528 	rc = usb_ep_queue(ep, req, GFP_KERNEL);
529 	if (rc) {
530 
531 		/* We can't do much more than wait for a reset */
532 		req->status = rc;
533 
534 		/*
535 		 * Note: currently the net2280 driver fails zero-length
536 		 * submissions if DMA is enabled.
537 		 */
538 		if (rc != -ESHUTDOWN &&
539 				!(rc == -EOPNOTSUPP && req->length == 0))
540 			WARNING(fsg, "error in submission: %s --> %d\n",
541 					ep->name, rc);
542 	}
543 	return rc;
544 }
545 
546 static bool start_in_transfer(struct fsg_common *common, struct fsg_buffhd *bh)
547 {
548 	int rc;
549 
550 	if (!fsg_is_set(common))
551 		return false;
552 	bh->state = BUF_STATE_SENDING;
553 	rc = start_transfer(common->fsg, common->fsg->bulk_in, bh->inreq);
554 	if (rc) {
555 		bh->state = BUF_STATE_EMPTY;
556 		if (rc == -ESHUTDOWN) {
557 			common->running = 0;
558 			return false;
559 		}
560 	}
561 	return true;
562 }
563 
564 static bool start_out_transfer(struct fsg_common *common, struct fsg_buffhd *bh)
565 {
566 	int rc;
567 
568 	if (!fsg_is_set(common))
569 		return false;
570 	bh->state = BUF_STATE_RECEIVING;
571 	rc = start_transfer(common->fsg, common->fsg->bulk_out, bh->outreq);
572 	if (rc) {
573 		bh->state = BUF_STATE_FULL;
574 		if (rc == -ESHUTDOWN) {
575 			common->running = 0;
576 			return false;
577 		}
578 	}
579 	return true;
580 }
581 
582 static int sleep_thread(struct fsg_common *common, bool can_freeze,
583 		struct fsg_buffhd *bh)
584 {
585 	int	rc;
586 
587 	/* Wait until a signal arrives or bh is no longer busy */
588 	if (can_freeze)
589 		/*
590 		 * synchronize with the smp_store_release(&bh->state) in
591 		 * bulk_in_complete() or bulk_out_complete()
592 		 */
593 		rc = wait_event_freezable(common->io_wait,
594 				bh && smp_load_acquire(&bh->state) >=
595 					BUF_STATE_EMPTY);
596 	else
597 		rc = wait_event_interruptible(common->io_wait,
598 				bh && smp_load_acquire(&bh->state) >=
599 					BUF_STATE_EMPTY);
600 	return rc ? -EINTR : 0;
601 }
602 
603 
604 /*-------------------------------------------------------------------------*/
605 
606 static int do_read(struct fsg_common *common)
607 {
608 	struct fsg_lun		*curlun = common->curlun;
609 	u64			lba;
610 	struct fsg_buffhd	*bh;
611 	int			rc;
612 	u32			amount_left;
613 	loff_t			file_offset, file_offset_tmp;
614 	unsigned int		amount;
615 	ssize_t			nread;
616 
617 	/*
618 	 * Get the starting Logical Block Address and check that it's
619 	 * not too big.
620 	 */
621 	if (common->cmnd[0] == READ_6)
622 		lba = get_unaligned_be24(&common->cmnd[1]);
623 	else {
624 		if (common->cmnd[0] == READ_16)
625 			lba = get_unaligned_be64(&common->cmnd[2]);
626 		else		/* READ_10 or READ_12 */
627 			lba = get_unaligned_be32(&common->cmnd[2]);
628 
629 		/*
630 		 * We allow DPO (Disable Page Out = don't save data in the
631 		 * cache) and FUA (Force Unit Access = don't read from the
632 		 * cache), but we don't implement them.
633 		 */
634 		if ((common->cmnd[1] & ~0x18) != 0) {
635 			curlun->sense_data = SS_INVALID_FIELD_IN_CDB;
636 			return -EINVAL;
637 		}
638 	}
639 	if (lba >= curlun->num_sectors) {
640 		curlun->sense_data = SS_LOGICAL_BLOCK_ADDRESS_OUT_OF_RANGE;
641 		return -EINVAL;
642 	}
643 	file_offset = ((loff_t) lba) << curlun->blkbits;
644 
645 	/* Carry out the file reads */
646 	amount_left = common->data_size_from_cmnd;
647 	if (unlikely(amount_left == 0))
648 		return -EIO;		/* No default reply */
649 
650 	for (;;) {
651 		/*
652 		 * Figure out how much we need to read:
653 		 * Try to read the remaining amount.
654 		 * But don't read more than the buffer size.
655 		 * And don't try to read past the end of the file.
656 		 */
657 		amount = min(amount_left, FSG_BUFLEN);
658 		amount = min((loff_t)amount,
659 			     curlun->file_length - file_offset);
660 
661 		/* Wait for the next buffer to become available */
662 		bh = common->next_buffhd_to_fill;
663 		rc = sleep_thread(common, false, bh);
664 		if (rc)
665 			return rc;
666 
667 		/*
668 		 * If we were asked to read past the end of file,
669 		 * end with an empty buffer.
670 		 */
671 		if (amount == 0) {
672 			curlun->sense_data =
673 					SS_LOGICAL_BLOCK_ADDRESS_OUT_OF_RANGE;
674 			curlun->sense_data_info =
675 					file_offset >> curlun->blkbits;
676 			curlun->info_valid = 1;
677 			bh->inreq->length = 0;
678 			bh->state = BUF_STATE_FULL;
679 			break;
680 		}
681 
682 		/* Perform the read */
683 		file_offset_tmp = file_offset;
684 		nread = kernel_read(curlun->filp, bh->buf, amount,
685 				&file_offset_tmp);
686 		VLDBG(curlun, "file read %u @ %llu -> %d\n", amount,
687 		      (unsigned long long)file_offset, (int)nread);
688 		if (signal_pending(current))
689 			return -EINTR;
690 
691 		if (nread < 0) {
692 			LDBG(curlun, "error in file read: %d\n", (int)nread);
693 			nread = 0;
694 		} else if (nread < amount) {
695 			LDBG(curlun, "partial file read: %d/%u\n",
696 			     (int)nread, amount);
697 			nread = round_down(nread, curlun->blksize);
698 		}
699 		file_offset  += nread;
700 		amount_left  -= nread;
701 		common->residue -= nread;
702 
703 		/*
704 		 * Except at the end of the transfer, nread will be
705 		 * equal to the buffer size, which is divisible by the
706 		 * bulk-in maxpacket size.
707 		 */
708 		bh->inreq->length = nread;
709 		bh->state = BUF_STATE_FULL;
710 
711 		/* If an error occurred, report it and its position */
712 		if (nread < amount) {
713 			curlun->sense_data = SS_UNRECOVERED_READ_ERROR;
714 			curlun->sense_data_info =
715 					file_offset >> curlun->blkbits;
716 			curlun->info_valid = 1;
717 			break;
718 		}
719 
720 		if (amount_left == 0)
721 			break;		/* No more left to read */
722 
723 		/* Send this buffer and go read some more */
724 		bh->inreq->zero = 0;
725 		if (!start_in_transfer(common, bh))
726 			/* Don't know what to do if common->fsg is NULL */
727 			return -EIO;
728 		common->next_buffhd_to_fill = bh->next;
729 	}
730 
731 	return -EIO;		/* No default reply */
732 }
733 
734 
735 /*-------------------------------------------------------------------------*/
736 
737 static int do_write(struct fsg_common *common)
738 {
739 	struct fsg_lun		*curlun = common->curlun;
740 	u64			lba;
741 	struct fsg_buffhd	*bh;
742 	int			get_some_more;
743 	u32			amount_left_to_req, amount_left_to_write;
744 	loff_t			usb_offset, file_offset, file_offset_tmp;
745 	unsigned int		amount;
746 	ssize_t			nwritten;
747 	int			rc;
748 
749 	if (curlun->ro) {
750 		curlun->sense_data = SS_WRITE_PROTECTED;
751 		return -EINVAL;
752 	}
753 	spin_lock(&curlun->filp->f_lock);
754 	curlun->filp->f_flags &= ~O_SYNC;	/* Default is not to wait */
755 	spin_unlock(&curlun->filp->f_lock);
756 
757 	/*
758 	 * Get the starting Logical Block Address and check that it's
759 	 * not too big
760 	 */
761 	if (common->cmnd[0] == WRITE_6)
762 		lba = get_unaligned_be24(&common->cmnd[1]);
763 	else {
764 		if (common->cmnd[0] == WRITE_16)
765 			lba = get_unaligned_be64(&common->cmnd[2]);
766 		else		/* WRITE_10 or WRITE_12 */
767 			lba = get_unaligned_be32(&common->cmnd[2]);
768 
769 		/*
770 		 * We allow DPO (Disable Page Out = don't save data in the
771 		 * cache) and FUA (Force Unit Access = write directly to the
772 		 * medium).  We don't implement DPO; we implement FUA by
773 		 * performing synchronous output.
774 		 */
775 		if (common->cmnd[1] & ~0x18) {
776 			curlun->sense_data = SS_INVALID_FIELD_IN_CDB;
777 			return -EINVAL;
778 		}
779 		if (!curlun->nofua && (common->cmnd[1] & 0x08)) { /* FUA */
780 			spin_lock(&curlun->filp->f_lock);
781 			curlun->filp->f_flags |= O_SYNC;
782 			spin_unlock(&curlun->filp->f_lock);
783 		}
784 	}
785 	if (lba >= curlun->num_sectors) {
786 		curlun->sense_data = SS_LOGICAL_BLOCK_ADDRESS_OUT_OF_RANGE;
787 		return -EINVAL;
788 	}
789 
790 	/* Carry out the file writes */
791 	get_some_more = 1;
792 	file_offset = usb_offset = ((loff_t) lba) << curlun->blkbits;
793 	amount_left_to_req = common->data_size_from_cmnd;
794 	amount_left_to_write = common->data_size_from_cmnd;
795 
796 	while (amount_left_to_write > 0) {
797 
798 		/* Queue a request for more data from the host */
799 		bh = common->next_buffhd_to_fill;
800 		if (bh->state == BUF_STATE_EMPTY && get_some_more) {
801 
802 			/*
803 			 * Figure out how much we want to get:
804 			 * Try to get the remaining amount,
805 			 * but not more than the buffer size.
806 			 */
807 			amount = min(amount_left_to_req, FSG_BUFLEN);
808 
809 			/* Beyond the end of the backing file? */
810 			if (usb_offset >= curlun->file_length) {
811 				get_some_more = 0;
812 				curlun->sense_data =
813 					SS_LOGICAL_BLOCK_ADDRESS_OUT_OF_RANGE;
814 				curlun->sense_data_info =
815 					usb_offset >> curlun->blkbits;
816 				curlun->info_valid = 1;
817 				continue;
818 			}
819 
820 			/* Get the next buffer */
821 			usb_offset += amount;
822 			common->usb_amount_left -= amount;
823 			amount_left_to_req -= amount;
824 			if (amount_left_to_req == 0)
825 				get_some_more = 0;
826 
827 			/*
828 			 * Except at the end of the transfer, amount will be
829 			 * equal to the buffer size, which is divisible by
830 			 * the bulk-out maxpacket size.
831 			 */
832 			set_bulk_out_req_length(common, bh, amount);
833 			if (!start_out_transfer(common, bh))
834 				/* Dunno what to do if common->fsg is NULL */
835 				return -EIO;
836 			common->next_buffhd_to_fill = bh->next;
837 			continue;
838 		}
839 
840 		/* Write the received data to the backing file */
841 		bh = common->next_buffhd_to_drain;
842 		if (bh->state == BUF_STATE_EMPTY && !get_some_more)
843 			break;			/* We stopped early */
844 
845 		/* Wait for the data to be received */
846 		rc = sleep_thread(common, false, bh);
847 		if (rc)
848 			return rc;
849 
850 		common->next_buffhd_to_drain = bh->next;
851 		bh->state = BUF_STATE_EMPTY;
852 
853 		/* Did something go wrong with the transfer? */
854 		if (bh->outreq->status != 0) {
855 			curlun->sense_data = SS_COMMUNICATION_FAILURE;
856 			curlun->sense_data_info =
857 					file_offset >> curlun->blkbits;
858 			curlun->info_valid = 1;
859 			break;
860 		}
861 
862 		amount = bh->outreq->actual;
863 		if (curlun->file_length - file_offset < amount) {
864 			LERROR(curlun, "write %u @ %llu beyond end %llu\n",
865 				       amount, (unsigned long long)file_offset,
866 				       (unsigned long long)curlun->file_length);
867 			amount = curlun->file_length - file_offset;
868 		}
869 
870 		/*
871 		 * Don't accept excess data.  The spec doesn't say
872 		 * what to do in this case.  We'll ignore the error.
873 		 */
874 		amount = min(amount, bh->bulk_out_intended_length);
875 
876 		/* Don't write a partial block */
877 		amount = round_down(amount, curlun->blksize);
878 		if (amount == 0)
879 			goto empty_write;
880 
881 		/* Perform the write */
882 		file_offset_tmp = file_offset;
883 		nwritten = kernel_write(curlun->filp, bh->buf, amount,
884 				&file_offset_tmp);
885 		VLDBG(curlun, "file write %u @ %llu -> %d\n", amount,
886 				(unsigned long long)file_offset, (int)nwritten);
887 		if (signal_pending(current))
888 			return -EINTR;		/* Interrupted! */
889 
890 		if (nwritten < 0) {
891 			LDBG(curlun, "error in file write: %d\n",
892 					(int) nwritten);
893 			nwritten = 0;
894 		} else if (nwritten < amount) {
895 			LDBG(curlun, "partial file write: %d/%u\n",
896 					(int) nwritten, amount);
897 			nwritten = round_down(nwritten, curlun->blksize);
898 		}
899 		file_offset += nwritten;
900 		amount_left_to_write -= nwritten;
901 		common->residue -= nwritten;
902 
903 		/* If an error occurred, report it and its position */
904 		if (nwritten < amount) {
905 			curlun->sense_data = SS_WRITE_ERROR;
906 			curlun->sense_data_info =
907 					file_offset >> curlun->blkbits;
908 			curlun->info_valid = 1;
909 			break;
910 		}
911 
912  empty_write:
913 		/* Did the host decide to stop early? */
914 		if (bh->outreq->actual < bh->bulk_out_intended_length) {
915 			common->short_packet_received = 1;
916 			break;
917 		}
918 	}
919 
920 	return -EIO;		/* No default reply */
921 }
922 
923 
924 /*-------------------------------------------------------------------------*/
925 
926 static int do_synchronize_cache(struct fsg_common *common)
927 {
928 	struct fsg_lun	*curlun = common->curlun;
929 	int		rc;
930 
931 	/* We ignore the requested LBA and write out all file's
932 	 * dirty data buffers. */
933 	rc = fsg_lun_fsync_sub(curlun);
934 	if (rc)
935 		curlun->sense_data = SS_WRITE_ERROR;
936 	return 0;
937 }
938 
939 
940 /*-------------------------------------------------------------------------*/
941 
942 static void invalidate_sub(struct fsg_lun *curlun)
943 {
944 	struct file	*filp = curlun->filp;
945 	struct inode	*inode = file_inode(filp);
946 	unsigned long __maybe_unused	rc;
947 
948 	rc = invalidate_mapping_pages(inode->i_mapping, 0, -1);
949 	VLDBG(curlun, "invalidate_mapping_pages -> %ld\n", rc);
950 }
951 
952 static int do_verify(struct fsg_common *common)
953 {
954 	struct fsg_lun		*curlun = common->curlun;
955 	u32			lba;
956 	u32			verification_length;
957 	struct fsg_buffhd	*bh = common->next_buffhd_to_fill;
958 	loff_t			file_offset, file_offset_tmp;
959 	u32			amount_left;
960 	unsigned int		amount;
961 	ssize_t			nread;
962 
963 	/*
964 	 * Get the starting Logical Block Address and check that it's
965 	 * not too big.
966 	 */
967 	lba = get_unaligned_be32(&common->cmnd[2]);
968 	if (lba >= curlun->num_sectors) {
969 		curlun->sense_data = SS_LOGICAL_BLOCK_ADDRESS_OUT_OF_RANGE;
970 		return -EINVAL;
971 	}
972 
973 	/*
974 	 * We allow DPO (Disable Page Out = don't save data in the
975 	 * cache) but we don't implement it.
976 	 */
977 	if (common->cmnd[1] & ~0x10) {
978 		curlun->sense_data = SS_INVALID_FIELD_IN_CDB;
979 		return -EINVAL;
980 	}
981 
982 	verification_length = get_unaligned_be16(&common->cmnd[7]);
983 	if (unlikely(verification_length == 0))
984 		return -EIO;		/* No default reply */
985 
986 	/* Prepare to carry out the file verify */
987 	amount_left = verification_length << curlun->blkbits;
988 	file_offset = ((loff_t) lba) << curlun->blkbits;
989 
990 	/* Write out all the dirty buffers before invalidating them */
991 	fsg_lun_fsync_sub(curlun);
992 	if (signal_pending(current))
993 		return -EINTR;
994 
995 	invalidate_sub(curlun);
996 	if (signal_pending(current))
997 		return -EINTR;
998 
999 	/* Just try to read the requested blocks */
1000 	while (amount_left > 0) {
1001 		/*
1002 		 * Figure out how much we need to read:
1003 		 * Try to read the remaining amount, but not more than
1004 		 * the buffer size.
1005 		 * And don't try to read past the end of the file.
1006 		 */
1007 		amount = min(amount_left, FSG_BUFLEN);
1008 		amount = min((loff_t)amount,
1009 			     curlun->file_length - file_offset);
1010 		if (amount == 0) {
1011 			curlun->sense_data =
1012 					SS_LOGICAL_BLOCK_ADDRESS_OUT_OF_RANGE;
1013 			curlun->sense_data_info =
1014 				file_offset >> curlun->blkbits;
1015 			curlun->info_valid = 1;
1016 			break;
1017 		}
1018 
1019 		/* Perform the read */
1020 		file_offset_tmp = file_offset;
1021 		nread = kernel_read(curlun->filp, bh->buf, amount,
1022 				&file_offset_tmp);
1023 		VLDBG(curlun, "file read %u @ %llu -> %d\n", amount,
1024 				(unsigned long long) file_offset,
1025 				(int) nread);
1026 		if (signal_pending(current))
1027 			return -EINTR;
1028 
1029 		if (nread < 0) {
1030 			LDBG(curlun, "error in file verify: %d\n", (int)nread);
1031 			nread = 0;
1032 		} else if (nread < amount) {
1033 			LDBG(curlun, "partial file verify: %d/%u\n",
1034 			     (int)nread, amount);
1035 			nread = round_down(nread, curlun->blksize);
1036 		}
1037 		if (nread == 0) {
1038 			curlun->sense_data = SS_UNRECOVERED_READ_ERROR;
1039 			curlun->sense_data_info =
1040 				file_offset >> curlun->blkbits;
1041 			curlun->info_valid = 1;
1042 			break;
1043 		}
1044 		file_offset += nread;
1045 		amount_left -= nread;
1046 	}
1047 	return 0;
1048 }
1049 
1050 
1051 /*-------------------------------------------------------------------------*/
1052 
1053 static int do_inquiry(struct fsg_common *common, struct fsg_buffhd *bh)
1054 {
1055 	struct fsg_lun *curlun = common->curlun;
1056 	u8	*buf = (u8 *) bh->buf;
1057 
1058 	if (!curlun) {		/* Unsupported LUNs are okay */
1059 		common->bad_lun_okay = 1;
1060 		memset(buf, 0, 36);
1061 		buf[0] = TYPE_NO_LUN;	/* Unsupported, no device-type */
1062 		buf[4] = 31;		/* Additional length */
1063 		return 36;
1064 	}
1065 
1066 	buf[0] = curlun->cdrom ? TYPE_ROM : TYPE_DISK;
1067 	buf[1] = curlun->removable ? 0x80 : 0;
1068 	buf[2] = 2;		/* ANSI SCSI level 2 */
1069 	buf[3] = 2;		/* SCSI-2 INQUIRY data format */
1070 	buf[4] = 31;		/* Additional length */
1071 	buf[5] = 0;		/* No special options */
1072 	buf[6] = 0;
1073 	buf[7] = 0;
1074 	if (curlun->inquiry_string[0])
1075 		memcpy(buf + 8, curlun->inquiry_string,
1076 		       sizeof(curlun->inquiry_string));
1077 	else
1078 		memcpy(buf + 8, common->inquiry_string,
1079 		       sizeof(common->inquiry_string));
1080 	return 36;
1081 }
1082 
1083 static int do_request_sense(struct fsg_common *common, struct fsg_buffhd *bh)
1084 {
1085 	struct fsg_lun	*curlun = common->curlun;
1086 	u8		*buf = (u8 *) bh->buf;
1087 	u32		sd, sdinfo;
1088 	int		valid;
1089 
1090 	/*
1091 	 * From the SCSI-2 spec., section 7.9 (Unit attention condition):
1092 	 *
1093 	 * If a REQUEST SENSE command is received from an initiator
1094 	 * with a pending unit attention condition (before the target
1095 	 * generates the contingent allegiance condition), then the
1096 	 * target shall either:
1097 	 *   a) report any pending sense data and preserve the unit
1098 	 *	attention condition on the logical unit, or,
1099 	 *   b) report the unit attention condition, may discard any
1100 	 *	pending sense data, and clear the unit attention
1101 	 *	condition on the logical unit for that initiator.
1102 	 *
1103 	 * FSG normally uses option a); enable this code to use option b).
1104 	 */
1105 #if 0
1106 	if (curlun && curlun->unit_attention_data != SS_NO_SENSE) {
1107 		curlun->sense_data = curlun->unit_attention_data;
1108 		curlun->unit_attention_data = SS_NO_SENSE;
1109 	}
1110 #endif
1111 
1112 	if (!curlun) {		/* Unsupported LUNs are okay */
1113 		common->bad_lun_okay = 1;
1114 		sd = SS_LOGICAL_UNIT_NOT_SUPPORTED;
1115 		sdinfo = 0;
1116 		valid = 0;
1117 	} else {
1118 		sd = curlun->sense_data;
1119 		sdinfo = curlun->sense_data_info;
1120 		valid = curlun->info_valid << 7;
1121 		curlun->sense_data = SS_NO_SENSE;
1122 		curlun->sense_data_info = 0;
1123 		curlun->info_valid = 0;
1124 	}
1125 
1126 	memset(buf, 0, 18);
1127 	buf[0] = valid | 0x70;			/* Valid, current error */
1128 	buf[2] = SK(sd);
1129 	put_unaligned_be32(sdinfo, &buf[3]);	/* Sense information */
1130 	buf[7] = 18 - 8;			/* Additional sense length */
1131 	buf[12] = ASC(sd);
1132 	buf[13] = ASCQ(sd);
1133 	return 18;
1134 }
1135 
1136 static int do_read_capacity(struct fsg_common *common, struct fsg_buffhd *bh)
1137 {
1138 	struct fsg_lun	*curlun = common->curlun;
1139 	u32		lba = get_unaligned_be32(&common->cmnd[2]);
1140 	int		pmi = common->cmnd[8];
1141 	u8		*buf = (u8 *)bh->buf;
1142 	u32		max_lba;
1143 
1144 	/* Check the PMI and LBA fields */
1145 	if (pmi > 1 || (pmi == 0 && lba != 0)) {
1146 		curlun->sense_data = SS_INVALID_FIELD_IN_CDB;
1147 		return -EINVAL;
1148 	}
1149 
1150 	if (curlun->num_sectors < 0x100000000ULL)
1151 		max_lba = curlun->num_sectors - 1;
1152 	else
1153 		max_lba = 0xffffffff;
1154 	put_unaligned_be32(max_lba, &buf[0]);		/* Max logical block */
1155 	put_unaligned_be32(curlun->blksize, &buf[4]);	/* Block length */
1156 	return 8;
1157 }
1158 
1159 static int do_read_capacity_16(struct fsg_common *common, struct fsg_buffhd *bh)
1160 {
1161 	struct fsg_lun  *curlun = common->curlun;
1162 	u64		lba = get_unaligned_be64(&common->cmnd[2]);
1163 	int		pmi = common->cmnd[14];
1164 	u8		*buf = (u8 *)bh->buf;
1165 
1166 	/* Check the PMI and LBA fields */
1167 	if (pmi > 1 || (pmi == 0 && lba != 0)) {
1168 		curlun->sense_data = SS_INVALID_FIELD_IN_CDB;
1169 		return -EINVAL;
1170 	}
1171 
1172 	put_unaligned_be64(curlun->num_sectors - 1, &buf[0]);
1173 							/* Max logical block */
1174 	put_unaligned_be32(curlun->blksize, &buf[8]);	/* Block length */
1175 
1176 	/* It is safe to keep other fields zeroed */
1177 	memset(&buf[12], 0, 32 - 12);
1178 	return 32;
1179 }
1180 
1181 static int do_read_header(struct fsg_common *common, struct fsg_buffhd *bh)
1182 {
1183 	struct fsg_lun	*curlun = common->curlun;
1184 	int		msf = common->cmnd[1] & 0x02;
1185 	u32		lba = get_unaligned_be32(&common->cmnd[2]);
1186 	u8		*buf = (u8 *)bh->buf;
1187 
1188 	if (common->cmnd[1] & ~0x02) {		/* Mask away MSF */
1189 		curlun->sense_data = SS_INVALID_FIELD_IN_CDB;
1190 		return -EINVAL;
1191 	}
1192 	if (lba >= curlun->num_sectors) {
1193 		curlun->sense_data = SS_LOGICAL_BLOCK_ADDRESS_OUT_OF_RANGE;
1194 		return -EINVAL;
1195 	}
1196 
1197 	memset(buf, 0, 8);
1198 	buf[0] = 0x01;		/* 2048 bytes of user data, rest is EC */
1199 	store_cdrom_address(&buf[4], msf, lba);
1200 	return 8;
1201 }
1202 
1203 static int do_read_toc(struct fsg_common *common, struct fsg_buffhd *bh)
1204 {
1205 	struct fsg_lun	*curlun = common->curlun;
1206 	int		msf = common->cmnd[1] & 0x02;
1207 	int		start_track = common->cmnd[6];
1208 	u8		*buf = (u8 *)bh->buf;
1209 	u8		format;
1210 	int		i, len;
1211 
1212 	format = common->cmnd[2] & 0xf;
1213 
1214 	if ((common->cmnd[1] & ~0x02) != 0 ||	/* Mask away MSF */
1215 			(start_track > 1 && format != 0x1)) {
1216 		curlun->sense_data = SS_INVALID_FIELD_IN_CDB;
1217 		return -EINVAL;
1218 	}
1219 
1220 	/*
1221 	 * Check if CDB is old style SFF-8020i
1222 	 * i.e. format is in 2 MSBs of byte 9
1223 	 * Mac OS-X host sends us this.
1224 	 */
1225 	if (format == 0)
1226 		format = (common->cmnd[9] >> 6) & 0x3;
1227 
1228 	switch (format) {
1229 	case 0:	/* Formatted TOC */
1230 	case 1:	/* Multi-session info */
1231 		len = 4 + 2*8;		/* 4 byte header + 2 descriptors */
1232 		memset(buf, 0, len);
1233 		buf[1] = len - 2;	/* TOC Length excludes length field */
1234 		buf[2] = 1;		/* First track number */
1235 		buf[3] = 1;		/* Last track number */
1236 		buf[5] = 0x16;		/* Data track, copying allowed */
1237 		buf[6] = 0x01;		/* Only track is number 1 */
1238 		store_cdrom_address(&buf[8], msf, 0);
1239 
1240 		buf[13] = 0x16;		/* Lead-out track is data */
1241 		buf[14] = 0xAA;		/* Lead-out track number */
1242 		store_cdrom_address(&buf[16], msf, curlun->num_sectors);
1243 		return len;
1244 
1245 	case 2:
1246 		/* Raw TOC */
1247 		len = 4 + 3*11;		/* 4 byte header + 3 descriptors */
1248 		memset(buf, 0, len);	/* Header + A0, A1 & A2 descriptors */
1249 		buf[1] = len - 2;	/* TOC Length excludes length field */
1250 		buf[2] = 1;		/* First complete session */
1251 		buf[3] = 1;		/* Last complete session */
1252 
1253 		buf += 4;
1254 		/* fill in A0, A1 and A2 points */
1255 		for (i = 0; i < 3; i++) {
1256 			buf[0] = 1;	/* Session number */
1257 			buf[1] = 0x16;	/* Data track, copying allowed */
1258 			/* 2 - Track number 0 ->  TOC */
1259 			buf[3] = 0xA0 + i; /* A0, A1, A2 point */
1260 			/* 4, 5, 6 - Min, sec, frame is zero */
1261 			buf[8] = 1;	/* Pmin: last track number */
1262 			buf += 11;	/* go to next track descriptor */
1263 		}
1264 		buf -= 11;		/* go back to A2 descriptor */
1265 
1266 		/* For A2, 7, 8, 9, 10 - zero, Pmin, Psec, Pframe of Lead out */
1267 		store_cdrom_address(&buf[7], msf, curlun->num_sectors);
1268 		return len;
1269 
1270 	default:
1271 		/* PMA, ATIP, CD-TEXT not supported/required */
1272 		curlun->sense_data = SS_INVALID_FIELD_IN_CDB;
1273 		return -EINVAL;
1274 	}
1275 }
1276 
1277 static int do_mode_sense(struct fsg_common *common, struct fsg_buffhd *bh)
1278 {
1279 	struct fsg_lun	*curlun = common->curlun;
1280 	int		mscmnd = common->cmnd[0];
1281 	u8		*buf = (u8 *) bh->buf;
1282 	u8		*buf0 = buf;
1283 	int		pc, page_code;
1284 	int		changeable_values, all_pages;
1285 	int		valid_page = 0;
1286 	int		len, limit;
1287 
1288 	if ((common->cmnd[1] & ~0x08) != 0) {	/* Mask away DBD */
1289 		curlun->sense_data = SS_INVALID_FIELD_IN_CDB;
1290 		return -EINVAL;
1291 	}
1292 	pc = common->cmnd[2] >> 6;
1293 	page_code = common->cmnd[2] & 0x3f;
1294 	if (pc == 3) {
1295 		curlun->sense_data = SS_SAVING_PARAMETERS_NOT_SUPPORTED;
1296 		return -EINVAL;
1297 	}
1298 	changeable_values = (pc == 1);
1299 	all_pages = (page_code == 0x3f);
1300 
1301 	/*
1302 	 * Write the mode parameter header.  Fixed values are: default
1303 	 * medium type, no cache control (DPOFUA), and no block descriptors.
1304 	 * The only variable value is the WriteProtect bit.  We will fill in
1305 	 * the mode data length later.
1306 	 */
1307 	memset(buf, 0, 8);
1308 	if (mscmnd == MODE_SENSE) {
1309 		buf[2] = (curlun->ro ? 0x80 : 0x00);		/* WP, DPOFUA */
1310 		buf += 4;
1311 		limit = 255;
1312 	} else {			/* MODE_SENSE_10 */
1313 		buf[3] = (curlun->ro ? 0x80 : 0x00);		/* WP, DPOFUA */
1314 		buf += 8;
1315 		limit = 65535;		/* Should really be FSG_BUFLEN */
1316 	}
1317 
1318 	/* No block descriptors */
1319 
1320 	/*
1321 	 * The mode pages, in numerical order.  The only page we support
1322 	 * is the Caching page.
1323 	 */
1324 	if (page_code == 0x08 || all_pages) {
1325 		valid_page = 1;
1326 		buf[0] = 0x08;		/* Page code */
1327 		buf[1] = 10;		/* Page length */
1328 		memset(buf+2, 0, 10);	/* None of the fields are changeable */
1329 
1330 		if (!changeable_values) {
1331 			buf[2] = 0x04;	/* Write cache enable, */
1332 					/* Read cache not disabled */
1333 					/* No cache retention priorities */
1334 			put_unaligned_be16(0xffff, &buf[4]);
1335 					/* Don't disable prefetch */
1336 					/* Minimum prefetch = 0 */
1337 			put_unaligned_be16(0xffff, &buf[8]);
1338 					/* Maximum prefetch */
1339 			put_unaligned_be16(0xffff, &buf[10]);
1340 					/* Maximum prefetch ceiling */
1341 		}
1342 		buf += 12;
1343 	}
1344 
1345 	/*
1346 	 * Check that a valid page was requested and the mode data length
1347 	 * isn't too long.
1348 	 */
1349 	len = buf - buf0;
1350 	if (!valid_page || len > limit) {
1351 		curlun->sense_data = SS_INVALID_FIELD_IN_CDB;
1352 		return -EINVAL;
1353 	}
1354 
1355 	/*  Store the mode data length */
1356 	if (mscmnd == MODE_SENSE)
1357 		buf0[0] = len - 1;
1358 	else
1359 		put_unaligned_be16(len - 2, buf0);
1360 	return len;
1361 }
1362 
1363 static int do_start_stop(struct fsg_common *common)
1364 {
1365 	struct fsg_lun	*curlun = common->curlun;
1366 	int		loej, start;
1367 
1368 	if (!curlun) {
1369 		return -EINVAL;
1370 	} else if (!curlun->removable) {
1371 		curlun->sense_data = SS_INVALID_COMMAND;
1372 		return -EINVAL;
1373 	} else if ((common->cmnd[1] & ~0x01) != 0 || /* Mask away Immed */
1374 		   (common->cmnd[4] & ~0x03) != 0) { /* Mask LoEj, Start */
1375 		curlun->sense_data = SS_INVALID_FIELD_IN_CDB;
1376 		return -EINVAL;
1377 	}
1378 
1379 	loej  = common->cmnd[4] & 0x02;
1380 	start = common->cmnd[4] & 0x01;
1381 
1382 	/*
1383 	 * Our emulation doesn't support mounting; the medium is
1384 	 * available for use as soon as it is loaded.
1385 	 */
1386 	if (start) {
1387 		if (!fsg_lun_is_open(curlun)) {
1388 			curlun->sense_data = SS_MEDIUM_NOT_PRESENT;
1389 			return -EINVAL;
1390 		}
1391 		return 0;
1392 	}
1393 
1394 	/* Are we allowed to unload the media? */
1395 	if (curlun->prevent_medium_removal) {
1396 		LDBG(curlun, "unload attempt prevented\n");
1397 		curlun->sense_data = SS_MEDIUM_REMOVAL_PREVENTED;
1398 		return -EINVAL;
1399 	}
1400 
1401 	if (!loej)
1402 		return 0;
1403 
1404 	up_read(&common->filesem);
1405 	down_write(&common->filesem);
1406 	fsg_lun_close(curlun);
1407 	up_write(&common->filesem);
1408 	down_read(&common->filesem);
1409 
1410 	return 0;
1411 }
1412 
1413 static int do_prevent_allow(struct fsg_common *common)
1414 {
1415 	struct fsg_lun	*curlun = common->curlun;
1416 	int		prevent;
1417 
1418 	if (!common->curlun) {
1419 		return -EINVAL;
1420 	} else if (!common->curlun->removable) {
1421 		common->curlun->sense_data = SS_INVALID_COMMAND;
1422 		return -EINVAL;
1423 	}
1424 
1425 	prevent = common->cmnd[4] & 0x01;
1426 	if ((common->cmnd[4] & ~0x01) != 0) {	/* Mask away Prevent */
1427 		curlun->sense_data = SS_INVALID_FIELD_IN_CDB;
1428 		return -EINVAL;
1429 	}
1430 
1431 	if (curlun->prevent_medium_removal && !prevent)
1432 		fsg_lun_fsync_sub(curlun);
1433 	curlun->prevent_medium_removal = prevent;
1434 	return 0;
1435 }
1436 
1437 static int do_read_format_capacities(struct fsg_common *common,
1438 			struct fsg_buffhd *bh)
1439 {
1440 	struct fsg_lun	*curlun = common->curlun;
1441 	u8		*buf = (u8 *) bh->buf;
1442 
1443 	buf[0] = buf[1] = buf[2] = 0;
1444 	buf[3] = 8;	/* Only the Current/Maximum Capacity Descriptor */
1445 	buf += 4;
1446 
1447 	put_unaligned_be32(curlun->num_sectors, &buf[0]);
1448 						/* Number of blocks */
1449 	put_unaligned_be32(curlun->blksize, &buf[4]);/* Block length */
1450 	buf[4] = 0x02;				/* Current capacity */
1451 	return 12;
1452 }
1453 
1454 static int do_mode_select(struct fsg_common *common, struct fsg_buffhd *bh)
1455 {
1456 	struct fsg_lun	*curlun = common->curlun;
1457 
1458 	/* We don't support MODE SELECT */
1459 	if (curlun)
1460 		curlun->sense_data = SS_INVALID_COMMAND;
1461 	return -EINVAL;
1462 }
1463 
1464 
1465 /*-------------------------------------------------------------------------*/
1466 
1467 static int halt_bulk_in_endpoint(struct fsg_dev *fsg)
1468 {
1469 	int	rc;
1470 
1471 	rc = fsg_set_halt(fsg, fsg->bulk_in);
1472 	if (rc == -EAGAIN)
1473 		VDBG(fsg, "delayed bulk-in endpoint halt\n");
1474 	while (rc != 0) {
1475 		if (rc != -EAGAIN) {
1476 			WARNING(fsg, "usb_ep_set_halt -> %d\n", rc);
1477 			rc = 0;
1478 			break;
1479 		}
1480 
1481 		/* Wait for a short time and then try again */
1482 		if (msleep_interruptible(100) != 0)
1483 			return -EINTR;
1484 		rc = usb_ep_set_halt(fsg->bulk_in);
1485 	}
1486 	return rc;
1487 }
1488 
1489 static int wedge_bulk_in_endpoint(struct fsg_dev *fsg)
1490 {
1491 	int	rc;
1492 
1493 	DBG(fsg, "bulk-in set wedge\n");
1494 	rc = usb_ep_set_wedge(fsg->bulk_in);
1495 	if (rc == -EAGAIN)
1496 		VDBG(fsg, "delayed bulk-in endpoint wedge\n");
1497 	while (rc != 0) {
1498 		if (rc != -EAGAIN) {
1499 			WARNING(fsg, "usb_ep_set_wedge -> %d\n", rc);
1500 			rc = 0;
1501 			break;
1502 		}
1503 
1504 		/* Wait for a short time and then try again */
1505 		if (msleep_interruptible(100) != 0)
1506 			return -EINTR;
1507 		rc = usb_ep_set_wedge(fsg->bulk_in);
1508 	}
1509 	return rc;
1510 }
1511 
1512 static int throw_away_data(struct fsg_common *common)
1513 {
1514 	struct fsg_buffhd	*bh, *bh2;
1515 	u32			amount;
1516 	int			rc;
1517 
1518 	for (bh = common->next_buffhd_to_drain;
1519 	     bh->state != BUF_STATE_EMPTY || common->usb_amount_left > 0;
1520 	     bh = common->next_buffhd_to_drain) {
1521 
1522 		/* Try to submit another request if we need one */
1523 		bh2 = common->next_buffhd_to_fill;
1524 		if (bh2->state == BUF_STATE_EMPTY &&
1525 				common->usb_amount_left > 0) {
1526 			amount = min(common->usb_amount_left, FSG_BUFLEN);
1527 
1528 			/*
1529 			 * Except at the end of the transfer, amount will be
1530 			 * equal to the buffer size, which is divisible by
1531 			 * the bulk-out maxpacket size.
1532 			 */
1533 			set_bulk_out_req_length(common, bh2, amount);
1534 			if (!start_out_transfer(common, bh2))
1535 				/* Dunno what to do if common->fsg is NULL */
1536 				return -EIO;
1537 			common->next_buffhd_to_fill = bh2->next;
1538 			common->usb_amount_left -= amount;
1539 			continue;
1540 		}
1541 
1542 		/* Wait for the data to be received */
1543 		rc = sleep_thread(common, false, bh);
1544 		if (rc)
1545 			return rc;
1546 
1547 		/* Throw away the data in a filled buffer */
1548 		bh->state = BUF_STATE_EMPTY;
1549 		common->next_buffhd_to_drain = bh->next;
1550 
1551 		/* A short packet or an error ends everything */
1552 		if (bh->outreq->actual < bh->bulk_out_intended_length ||
1553 				bh->outreq->status != 0) {
1554 			raise_exception(common, FSG_STATE_ABORT_BULK_OUT);
1555 			return -EINTR;
1556 		}
1557 	}
1558 	return 0;
1559 }
1560 
1561 static int finish_reply(struct fsg_common *common)
1562 {
1563 	struct fsg_buffhd	*bh = common->next_buffhd_to_fill;
1564 	int			rc = 0;
1565 
1566 	switch (common->data_dir) {
1567 	case DATA_DIR_NONE:
1568 		break;			/* Nothing to send */
1569 
1570 	/*
1571 	 * If we don't know whether the host wants to read or write,
1572 	 * this must be CB or CBI with an unknown command.  We mustn't
1573 	 * try to send or receive any data.  So stall both bulk pipes
1574 	 * if we can and wait for a reset.
1575 	 */
1576 	case DATA_DIR_UNKNOWN:
1577 		if (!common->can_stall) {
1578 			/* Nothing */
1579 		} else if (fsg_is_set(common)) {
1580 			fsg_set_halt(common->fsg, common->fsg->bulk_out);
1581 			rc = halt_bulk_in_endpoint(common->fsg);
1582 		} else {
1583 			/* Don't know what to do if common->fsg is NULL */
1584 			rc = -EIO;
1585 		}
1586 		break;
1587 
1588 	/* All but the last buffer of data must have already been sent */
1589 	case DATA_DIR_TO_HOST:
1590 		if (common->data_size == 0) {
1591 			/* Nothing to send */
1592 
1593 		/* Don't know what to do if common->fsg is NULL */
1594 		} else if (!fsg_is_set(common)) {
1595 			rc = -EIO;
1596 
1597 		/* If there's no residue, simply send the last buffer */
1598 		} else if (common->residue == 0) {
1599 			bh->inreq->zero = 0;
1600 			if (!start_in_transfer(common, bh))
1601 				return -EIO;
1602 			common->next_buffhd_to_fill = bh->next;
1603 
1604 		/*
1605 		 * For Bulk-only, mark the end of the data with a short
1606 		 * packet.  If we are allowed to stall, halt the bulk-in
1607 		 * endpoint.  (Note: This violates the Bulk-Only Transport
1608 		 * specification, which requires us to pad the data if we
1609 		 * don't halt the endpoint.  Presumably nobody will mind.)
1610 		 */
1611 		} else {
1612 			bh->inreq->zero = 1;
1613 			if (!start_in_transfer(common, bh))
1614 				rc = -EIO;
1615 			common->next_buffhd_to_fill = bh->next;
1616 			if (common->can_stall)
1617 				rc = halt_bulk_in_endpoint(common->fsg);
1618 		}
1619 		break;
1620 
1621 	/*
1622 	 * We have processed all we want from the data the host has sent.
1623 	 * There may still be outstanding bulk-out requests.
1624 	 */
1625 	case DATA_DIR_FROM_HOST:
1626 		if (common->residue == 0) {
1627 			/* Nothing to receive */
1628 
1629 		/* Did the host stop sending unexpectedly early? */
1630 		} else if (common->short_packet_received) {
1631 			raise_exception(common, FSG_STATE_ABORT_BULK_OUT);
1632 			rc = -EINTR;
1633 
1634 		/*
1635 		 * We haven't processed all the incoming data.  Even though
1636 		 * we may be allowed to stall, doing so would cause a race.
1637 		 * The controller may already have ACK'ed all the remaining
1638 		 * bulk-out packets, in which case the host wouldn't see a
1639 		 * STALL.  Not realizing the endpoint was halted, it wouldn't
1640 		 * clear the halt -- leading to problems later on.
1641 		 */
1642 #if 0
1643 		} else if (common->can_stall) {
1644 			if (fsg_is_set(common))
1645 				fsg_set_halt(common->fsg,
1646 					     common->fsg->bulk_out);
1647 			raise_exception(common, FSG_STATE_ABORT_BULK_OUT);
1648 			rc = -EINTR;
1649 #endif
1650 
1651 		/*
1652 		 * We can't stall.  Read in the excess data and throw it
1653 		 * all away.
1654 		 */
1655 		} else {
1656 			rc = throw_away_data(common);
1657 		}
1658 		break;
1659 	}
1660 	return rc;
1661 }
1662 
1663 static void send_status(struct fsg_common *common)
1664 {
1665 	struct fsg_lun		*curlun = common->curlun;
1666 	struct fsg_buffhd	*bh;
1667 	struct bulk_cs_wrap	*csw;
1668 	int			rc;
1669 	u8			status = US_BULK_STAT_OK;
1670 	u32			sd, sdinfo = 0;
1671 
1672 	/* Wait for the next buffer to become available */
1673 	bh = common->next_buffhd_to_fill;
1674 	rc = sleep_thread(common, false, bh);
1675 	if (rc)
1676 		return;
1677 
1678 	if (curlun) {
1679 		sd = curlun->sense_data;
1680 		sdinfo = curlun->sense_data_info;
1681 	} else if (common->bad_lun_okay)
1682 		sd = SS_NO_SENSE;
1683 	else
1684 		sd = SS_LOGICAL_UNIT_NOT_SUPPORTED;
1685 
1686 	if (common->phase_error) {
1687 		DBG(common, "sending phase-error status\n");
1688 		status = US_BULK_STAT_PHASE;
1689 		sd = SS_INVALID_COMMAND;
1690 	} else if (sd != SS_NO_SENSE) {
1691 		DBG(common, "sending command-failure status\n");
1692 		status = US_BULK_STAT_FAIL;
1693 		VDBG(common, "  sense data: SK x%02x, ASC x%02x, ASCQ x%02x;"
1694 				"  info x%x\n",
1695 				SK(sd), ASC(sd), ASCQ(sd), sdinfo);
1696 	}
1697 
1698 	/* Store and send the Bulk-only CSW */
1699 	csw = (void *)bh->buf;
1700 
1701 	csw->Signature = cpu_to_le32(US_BULK_CS_SIGN);
1702 	csw->Tag = common->tag;
1703 	csw->Residue = cpu_to_le32(common->residue);
1704 	csw->Status = status;
1705 
1706 	bh->inreq->length = US_BULK_CS_WRAP_LEN;
1707 	bh->inreq->zero = 0;
1708 	if (!start_in_transfer(common, bh))
1709 		/* Don't know what to do if common->fsg is NULL */
1710 		return;
1711 
1712 	common->next_buffhd_to_fill = bh->next;
1713 	return;
1714 }
1715 
1716 
1717 /*-------------------------------------------------------------------------*/
1718 
1719 /*
1720  * Check whether the command is properly formed and whether its data size
1721  * and direction agree with the values we already have.
1722  */
1723 static int check_command(struct fsg_common *common, int cmnd_size,
1724 			 enum data_direction data_dir, unsigned int mask,
1725 			 int needs_medium, const char *name)
1726 {
1727 	int			i;
1728 	unsigned int		lun = common->cmnd[1] >> 5;
1729 	static const char	dirletter[4] = {'u', 'o', 'i', 'n'};
1730 	char			hdlen[20];
1731 	struct fsg_lun		*curlun;
1732 
1733 	hdlen[0] = 0;
1734 	if (common->data_dir != DATA_DIR_UNKNOWN)
1735 		sprintf(hdlen, ", H%c=%u", dirletter[(int) common->data_dir],
1736 			common->data_size);
1737 	VDBG(common, "SCSI command: %s;  Dc=%d, D%c=%u;  Hc=%d%s\n",
1738 	     name, cmnd_size, dirletter[(int) data_dir],
1739 	     common->data_size_from_cmnd, common->cmnd_size, hdlen);
1740 
1741 	/*
1742 	 * We can't reply at all until we know the correct data direction
1743 	 * and size.
1744 	 */
1745 	if (common->data_size_from_cmnd == 0)
1746 		data_dir = DATA_DIR_NONE;
1747 	if (common->data_size < common->data_size_from_cmnd) {
1748 		/*
1749 		 * Host data size < Device data size is a phase error.
1750 		 * Carry out the command, but only transfer as much as
1751 		 * we are allowed.
1752 		 */
1753 		common->data_size_from_cmnd = common->data_size;
1754 		common->phase_error = 1;
1755 	}
1756 	common->residue = common->data_size;
1757 	common->usb_amount_left = common->data_size;
1758 
1759 	/* Conflicting data directions is a phase error */
1760 	if (common->data_dir != data_dir && common->data_size_from_cmnd > 0) {
1761 		common->phase_error = 1;
1762 		return -EINVAL;
1763 	}
1764 
1765 	/* Verify the length of the command itself */
1766 	if (cmnd_size != common->cmnd_size) {
1767 
1768 		/*
1769 		 * Special case workaround: There are plenty of buggy SCSI
1770 		 * implementations. Many have issues with cbw->Length
1771 		 * field passing a wrong command size. For those cases we
1772 		 * always try to work around the problem by using the length
1773 		 * sent by the host side provided it is at least as large
1774 		 * as the correct command length.
1775 		 * Examples of such cases would be MS-Windows, which issues
1776 		 * REQUEST SENSE with cbw->Length == 12 where it should
1777 		 * be 6, and xbox360 issuing INQUIRY, TEST UNIT READY and
1778 		 * REQUEST SENSE with cbw->Length == 10 where it should
1779 		 * be 6 as well.
1780 		 */
1781 		if (cmnd_size <= common->cmnd_size) {
1782 			DBG(common, "%s is buggy! Expected length %d "
1783 			    "but we got %d\n", name,
1784 			    cmnd_size, common->cmnd_size);
1785 			cmnd_size = common->cmnd_size;
1786 		} else {
1787 			common->phase_error = 1;
1788 			return -EINVAL;
1789 		}
1790 	}
1791 
1792 	/* Check that the LUN values are consistent */
1793 	if (common->lun != lun)
1794 		DBG(common, "using LUN %u from CBW, not LUN %u from CDB\n",
1795 		    common->lun, lun);
1796 
1797 	/* Check the LUN */
1798 	curlun = common->curlun;
1799 	if (curlun) {
1800 		if (common->cmnd[0] != REQUEST_SENSE) {
1801 			curlun->sense_data = SS_NO_SENSE;
1802 			curlun->sense_data_info = 0;
1803 			curlun->info_valid = 0;
1804 		}
1805 	} else {
1806 		common->bad_lun_okay = 0;
1807 
1808 		/*
1809 		 * INQUIRY and REQUEST SENSE commands are explicitly allowed
1810 		 * to use unsupported LUNs; all others may not.
1811 		 */
1812 		if (common->cmnd[0] != INQUIRY &&
1813 		    common->cmnd[0] != REQUEST_SENSE) {
1814 			DBG(common, "unsupported LUN %u\n", common->lun);
1815 			return -EINVAL;
1816 		}
1817 	}
1818 
1819 	/*
1820 	 * If a unit attention condition exists, only INQUIRY and
1821 	 * REQUEST SENSE commands are allowed; anything else must fail.
1822 	 */
1823 	if (curlun && curlun->unit_attention_data != SS_NO_SENSE &&
1824 	    common->cmnd[0] != INQUIRY &&
1825 	    common->cmnd[0] != REQUEST_SENSE) {
1826 		curlun->sense_data = curlun->unit_attention_data;
1827 		curlun->unit_attention_data = SS_NO_SENSE;
1828 		return -EINVAL;
1829 	}
1830 
1831 	/* Check that only command bytes listed in the mask are non-zero */
1832 	common->cmnd[1] &= 0x1f;			/* Mask away the LUN */
1833 	for (i = 1; i < cmnd_size; ++i) {
1834 		if (common->cmnd[i] && !(mask & (1 << i))) {
1835 			if (curlun)
1836 				curlun->sense_data = SS_INVALID_FIELD_IN_CDB;
1837 			return -EINVAL;
1838 		}
1839 	}
1840 
1841 	/* If the medium isn't mounted and the command needs to access
1842 	 * it, return an error. */
1843 	if (curlun && !fsg_lun_is_open(curlun) && needs_medium) {
1844 		curlun->sense_data = SS_MEDIUM_NOT_PRESENT;
1845 		return -EINVAL;
1846 	}
1847 
1848 	return 0;
1849 }
1850 
1851 /* wrapper of check_command for data size in blocks handling */
1852 static int check_command_size_in_blocks(struct fsg_common *common,
1853 		int cmnd_size, enum data_direction data_dir,
1854 		unsigned int mask, int needs_medium, const char *name)
1855 {
1856 	if (common->curlun)
1857 		common->data_size_from_cmnd <<= common->curlun->blkbits;
1858 	return check_command(common, cmnd_size, data_dir,
1859 			mask, needs_medium, name);
1860 }
1861 
1862 static int do_scsi_command(struct fsg_common *common)
1863 {
1864 	struct fsg_buffhd	*bh;
1865 	int			rc;
1866 	int			reply = -EINVAL;
1867 	int			i;
1868 	static char		unknown[16];
1869 
1870 	dump_cdb(common);
1871 
1872 	/* Wait for the next buffer to become available for data or status */
1873 	bh = common->next_buffhd_to_fill;
1874 	common->next_buffhd_to_drain = bh;
1875 	rc = sleep_thread(common, false, bh);
1876 	if (rc)
1877 		return rc;
1878 
1879 	common->phase_error = 0;
1880 	common->short_packet_received = 0;
1881 
1882 	down_read(&common->filesem);	/* We're using the backing file */
1883 	switch (common->cmnd[0]) {
1884 
1885 	case INQUIRY:
1886 		common->data_size_from_cmnd = common->cmnd[4];
1887 		reply = check_command(common, 6, DATA_DIR_TO_HOST,
1888 				      (1<<4), 0,
1889 				      "INQUIRY");
1890 		if (reply == 0)
1891 			reply = do_inquiry(common, bh);
1892 		break;
1893 
1894 	case MODE_SELECT:
1895 		common->data_size_from_cmnd = common->cmnd[4];
1896 		reply = check_command(common, 6, DATA_DIR_FROM_HOST,
1897 				      (1<<1) | (1<<4), 0,
1898 				      "MODE SELECT(6)");
1899 		if (reply == 0)
1900 			reply = do_mode_select(common, bh);
1901 		break;
1902 
1903 	case MODE_SELECT_10:
1904 		common->data_size_from_cmnd =
1905 			get_unaligned_be16(&common->cmnd[7]);
1906 		reply = check_command(common, 10, DATA_DIR_FROM_HOST,
1907 				      (1<<1) | (3<<7), 0,
1908 				      "MODE SELECT(10)");
1909 		if (reply == 0)
1910 			reply = do_mode_select(common, bh);
1911 		break;
1912 
1913 	case MODE_SENSE:
1914 		common->data_size_from_cmnd = common->cmnd[4];
1915 		reply = check_command(common, 6, DATA_DIR_TO_HOST,
1916 				      (1<<1) | (1<<2) | (1<<4), 0,
1917 				      "MODE SENSE(6)");
1918 		if (reply == 0)
1919 			reply = do_mode_sense(common, bh);
1920 		break;
1921 
1922 	case MODE_SENSE_10:
1923 		common->data_size_from_cmnd =
1924 			get_unaligned_be16(&common->cmnd[7]);
1925 		reply = check_command(common, 10, DATA_DIR_TO_HOST,
1926 				      (1<<1) | (1<<2) | (3<<7), 0,
1927 				      "MODE SENSE(10)");
1928 		if (reply == 0)
1929 			reply = do_mode_sense(common, bh);
1930 		break;
1931 
1932 	case ALLOW_MEDIUM_REMOVAL:
1933 		common->data_size_from_cmnd = 0;
1934 		reply = check_command(common, 6, DATA_DIR_NONE,
1935 				      (1<<4), 0,
1936 				      "PREVENT-ALLOW MEDIUM REMOVAL");
1937 		if (reply == 0)
1938 			reply = do_prevent_allow(common);
1939 		break;
1940 
1941 	case READ_6:
1942 		i = common->cmnd[4];
1943 		common->data_size_from_cmnd = (i == 0) ? 256 : i;
1944 		reply = check_command_size_in_blocks(common, 6,
1945 				      DATA_DIR_TO_HOST,
1946 				      (7<<1) | (1<<4), 1,
1947 				      "READ(6)");
1948 		if (reply == 0)
1949 			reply = do_read(common);
1950 		break;
1951 
1952 	case READ_10:
1953 		common->data_size_from_cmnd =
1954 				get_unaligned_be16(&common->cmnd[7]);
1955 		reply = check_command_size_in_blocks(common, 10,
1956 				      DATA_DIR_TO_HOST,
1957 				      (1<<1) | (0xf<<2) | (3<<7), 1,
1958 				      "READ(10)");
1959 		if (reply == 0)
1960 			reply = do_read(common);
1961 		break;
1962 
1963 	case READ_12:
1964 		common->data_size_from_cmnd =
1965 				get_unaligned_be32(&common->cmnd[6]);
1966 		reply = check_command_size_in_blocks(common, 12,
1967 				      DATA_DIR_TO_HOST,
1968 				      (1<<1) | (0xf<<2) | (0xf<<6), 1,
1969 				      "READ(12)");
1970 		if (reply == 0)
1971 			reply = do_read(common);
1972 		break;
1973 
1974 	case READ_16:
1975 		common->data_size_from_cmnd =
1976 				get_unaligned_be32(&common->cmnd[10]);
1977 		reply = check_command_size_in_blocks(common, 16,
1978 				      DATA_DIR_TO_HOST,
1979 				      (1<<1) | (0xff<<2) | (0xf<<10), 1,
1980 				      "READ(16)");
1981 		if (reply == 0)
1982 			reply = do_read(common);
1983 		break;
1984 
1985 	case READ_CAPACITY:
1986 		common->data_size_from_cmnd = 8;
1987 		reply = check_command(common, 10, DATA_DIR_TO_HOST,
1988 				      (0xf<<2) | (1<<8), 1,
1989 				      "READ CAPACITY");
1990 		if (reply == 0)
1991 			reply = do_read_capacity(common, bh);
1992 		break;
1993 
1994 	case READ_HEADER:
1995 		if (!common->curlun || !common->curlun->cdrom)
1996 			goto unknown_cmnd;
1997 		common->data_size_from_cmnd =
1998 			get_unaligned_be16(&common->cmnd[7]);
1999 		reply = check_command(common, 10, DATA_DIR_TO_HOST,
2000 				      (3<<7) | (0x1f<<1), 1,
2001 				      "READ HEADER");
2002 		if (reply == 0)
2003 			reply = do_read_header(common, bh);
2004 		break;
2005 
2006 	case READ_TOC:
2007 		if (!common->curlun || !common->curlun->cdrom)
2008 			goto unknown_cmnd;
2009 		common->data_size_from_cmnd =
2010 			get_unaligned_be16(&common->cmnd[7]);
2011 		reply = check_command(common, 10, DATA_DIR_TO_HOST,
2012 				      (0xf<<6) | (3<<1), 1,
2013 				      "READ TOC");
2014 		if (reply == 0)
2015 			reply = do_read_toc(common, bh);
2016 		break;
2017 
2018 	case READ_FORMAT_CAPACITIES:
2019 		common->data_size_from_cmnd =
2020 			get_unaligned_be16(&common->cmnd[7]);
2021 		reply = check_command(common, 10, DATA_DIR_TO_HOST,
2022 				      (3<<7), 1,
2023 				      "READ FORMAT CAPACITIES");
2024 		if (reply == 0)
2025 			reply = do_read_format_capacities(common, bh);
2026 		break;
2027 
2028 	case REQUEST_SENSE:
2029 		common->data_size_from_cmnd = common->cmnd[4];
2030 		reply = check_command(common, 6, DATA_DIR_TO_HOST,
2031 				      (1<<4), 0,
2032 				      "REQUEST SENSE");
2033 		if (reply == 0)
2034 			reply = do_request_sense(common, bh);
2035 		break;
2036 
2037 	case SERVICE_ACTION_IN_16:
2038 		switch (common->cmnd[1] & 0x1f) {
2039 
2040 		case SAI_READ_CAPACITY_16:
2041 			common->data_size_from_cmnd =
2042 				get_unaligned_be32(&common->cmnd[10]);
2043 			reply = check_command(common, 16, DATA_DIR_TO_HOST,
2044 					      (1<<1) | (0xff<<2) | (0xf<<10) |
2045 					      (1<<14), 1,
2046 					      "READ CAPACITY(16)");
2047 			if (reply == 0)
2048 				reply = do_read_capacity_16(common, bh);
2049 			break;
2050 
2051 		default:
2052 			goto unknown_cmnd;
2053 		}
2054 		break;
2055 
2056 	case START_STOP:
2057 		common->data_size_from_cmnd = 0;
2058 		reply = check_command(common, 6, DATA_DIR_NONE,
2059 				      (1<<1) | (1<<4), 0,
2060 				      "START-STOP UNIT");
2061 		if (reply == 0)
2062 			reply = do_start_stop(common);
2063 		break;
2064 
2065 	case SYNCHRONIZE_CACHE:
2066 		common->data_size_from_cmnd = 0;
2067 		reply = check_command(common, 10, DATA_DIR_NONE,
2068 				      (0xf<<2) | (3<<7), 1,
2069 				      "SYNCHRONIZE CACHE");
2070 		if (reply == 0)
2071 			reply = do_synchronize_cache(common);
2072 		break;
2073 
2074 	case TEST_UNIT_READY:
2075 		common->data_size_from_cmnd = 0;
2076 		reply = check_command(common, 6, DATA_DIR_NONE,
2077 				0, 1,
2078 				"TEST UNIT READY");
2079 		break;
2080 
2081 	/*
2082 	 * Although optional, this command is used by MS-Windows.  We
2083 	 * support a minimal version: BytChk must be 0.
2084 	 */
2085 	case VERIFY:
2086 		common->data_size_from_cmnd = 0;
2087 		reply = check_command(common, 10, DATA_DIR_NONE,
2088 				      (1<<1) | (0xf<<2) | (3<<7), 1,
2089 				      "VERIFY");
2090 		if (reply == 0)
2091 			reply = do_verify(common);
2092 		break;
2093 
2094 	case WRITE_6:
2095 		i = common->cmnd[4];
2096 		common->data_size_from_cmnd = (i == 0) ? 256 : i;
2097 		reply = check_command_size_in_blocks(common, 6,
2098 				      DATA_DIR_FROM_HOST,
2099 				      (7<<1) | (1<<4), 1,
2100 				      "WRITE(6)");
2101 		if (reply == 0)
2102 			reply = do_write(common);
2103 		break;
2104 
2105 	case WRITE_10:
2106 		common->data_size_from_cmnd =
2107 				get_unaligned_be16(&common->cmnd[7]);
2108 		reply = check_command_size_in_blocks(common, 10,
2109 				      DATA_DIR_FROM_HOST,
2110 				      (1<<1) | (0xf<<2) | (3<<7), 1,
2111 				      "WRITE(10)");
2112 		if (reply == 0)
2113 			reply = do_write(common);
2114 		break;
2115 
2116 	case WRITE_12:
2117 		common->data_size_from_cmnd =
2118 				get_unaligned_be32(&common->cmnd[6]);
2119 		reply = check_command_size_in_blocks(common, 12,
2120 				      DATA_DIR_FROM_HOST,
2121 				      (1<<1) | (0xf<<2) | (0xf<<6), 1,
2122 				      "WRITE(12)");
2123 		if (reply == 0)
2124 			reply = do_write(common);
2125 		break;
2126 
2127 	case WRITE_16:
2128 		common->data_size_from_cmnd =
2129 				get_unaligned_be32(&common->cmnd[10]);
2130 		reply = check_command_size_in_blocks(common, 16,
2131 				      DATA_DIR_FROM_HOST,
2132 				      (1<<1) | (0xff<<2) | (0xf<<10), 1,
2133 				      "WRITE(16)");
2134 		if (reply == 0)
2135 			reply = do_write(common);
2136 		break;
2137 
2138 	/*
2139 	 * Some mandatory commands that we recognize but don't implement.
2140 	 * They don't mean much in this setting.  It's left as an exercise
2141 	 * for anyone interested to implement RESERVE and RELEASE in terms
2142 	 * of Posix locks.
2143 	 */
2144 	case FORMAT_UNIT:
2145 	case RELEASE:
2146 	case RESERVE:
2147 	case SEND_DIAGNOSTIC:
2148 
2149 	default:
2150 unknown_cmnd:
2151 		common->data_size_from_cmnd = 0;
2152 		sprintf(unknown, "Unknown x%02x", common->cmnd[0]);
2153 		reply = check_command(common, common->cmnd_size,
2154 				      DATA_DIR_UNKNOWN, ~0, 0, unknown);
2155 		if (reply == 0) {
2156 			common->curlun->sense_data = SS_INVALID_COMMAND;
2157 			reply = -EINVAL;
2158 		}
2159 		break;
2160 	}
2161 	up_read(&common->filesem);
2162 
2163 	if (reply == -EINTR || signal_pending(current))
2164 		return -EINTR;
2165 
2166 	/* Set up the single reply buffer for finish_reply() */
2167 	if (reply == -EINVAL)
2168 		reply = 0;		/* Error reply length */
2169 	if (reply >= 0 && common->data_dir == DATA_DIR_TO_HOST) {
2170 		reply = min((u32)reply, common->data_size_from_cmnd);
2171 		bh->inreq->length = reply;
2172 		bh->state = BUF_STATE_FULL;
2173 		common->residue -= reply;
2174 	}				/* Otherwise it's already set */
2175 
2176 	return 0;
2177 }
2178 
2179 
2180 /*-------------------------------------------------------------------------*/
2181 
2182 static int received_cbw(struct fsg_dev *fsg, struct fsg_buffhd *bh)
2183 {
2184 	struct usb_request	*req = bh->outreq;
2185 	struct bulk_cb_wrap	*cbw = req->buf;
2186 	struct fsg_common	*common = fsg->common;
2187 
2188 	/* Was this a real packet?  Should it be ignored? */
2189 	if (req->status || test_bit(IGNORE_BULK_OUT, &fsg->atomic_bitflags))
2190 		return -EINVAL;
2191 
2192 	/* Is the CBW valid? */
2193 	if (req->actual != US_BULK_CB_WRAP_LEN ||
2194 			cbw->Signature != cpu_to_le32(
2195 				US_BULK_CB_SIGN)) {
2196 		DBG(fsg, "invalid CBW: len %u sig 0x%x\n",
2197 				req->actual,
2198 				le32_to_cpu(cbw->Signature));
2199 
2200 		/*
2201 		 * The Bulk-only spec says we MUST stall the IN endpoint
2202 		 * (6.6.1), so it's unavoidable.  It also says we must
2203 		 * retain this state until the next reset, but there's
2204 		 * no way to tell the controller driver it should ignore
2205 		 * Clear-Feature(HALT) requests.
2206 		 *
2207 		 * We aren't required to halt the OUT endpoint; instead
2208 		 * we can simply accept and discard any data received
2209 		 * until the next reset.
2210 		 */
2211 		wedge_bulk_in_endpoint(fsg);
2212 		set_bit(IGNORE_BULK_OUT, &fsg->atomic_bitflags);
2213 		return -EINVAL;
2214 	}
2215 
2216 	/* Is the CBW meaningful? */
2217 	if (cbw->Lun >= ARRAY_SIZE(common->luns) ||
2218 	    cbw->Flags & ~US_BULK_FLAG_IN || cbw->Length <= 0 ||
2219 	    cbw->Length > MAX_COMMAND_SIZE) {
2220 		DBG(fsg, "non-meaningful CBW: lun = %u, flags = 0x%x, "
2221 				"cmdlen %u\n",
2222 				cbw->Lun, cbw->Flags, cbw->Length);
2223 
2224 		/*
2225 		 * We can do anything we want here, so let's stall the
2226 		 * bulk pipes if we are allowed to.
2227 		 */
2228 		if (common->can_stall) {
2229 			fsg_set_halt(fsg, fsg->bulk_out);
2230 			halt_bulk_in_endpoint(fsg);
2231 		}
2232 		return -EINVAL;
2233 	}
2234 
2235 	/* Save the command for later */
2236 	common->cmnd_size = cbw->Length;
2237 	memcpy(common->cmnd, cbw->CDB, common->cmnd_size);
2238 	if (cbw->Flags & US_BULK_FLAG_IN)
2239 		common->data_dir = DATA_DIR_TO_HOST;
2240 	else
2241 		common->data_dir = DATA_DIR_FROM_HOST;
2242 	common->data_size = le32_to_cpu(cbw->DataTransferLength);
2243 	if (common->data_size == 0)
2244 		common->data_dir = DATA_DIR_NONE;
2245 	common->lun = cbw->Lun;
2246 	if (common->lun < ARRAY_SIZE(common->luns))
2247 		common->curlun = common->luns[common->lun];
2248 	else
2249 		common->curlun = NULL;
2250 	common->tag = cbw->Tag;
2251 	return 0;
2252 }
2253 
2254 static int get_next_command(struct fsg_common *common)
2255 {
2256 	struct fsg_buffhd	*bh;
2257 	int			rc = 0;
2258 
2259 	/* Wait for the next buffer to become available */
2260 	bh = common->next_buffhd_to_fill;
2261 	rc = sleep_thread(common, true, bh);
2262 	if (rc)
2263 		return rc;
2264 
2265 	/* Queue a request to read a Bulk-only CBW */
2266 	set_bulk_out_req_length(common, bh, US_BULK_CB_WRAP_LEN);
2267 	if (!start_out_transfer(common, bh))
2268 		/* Don't know what to do if common->fsg is NULL */
2269 		return -EIO;
2270 
2271 	/*
2272 	 * We will drain the buffer in software, which means we
2273 	 * can reuse it for the next filling.  No need to advance
2274 	 * next_buffhd_to_fill.
2275 	 */
2276 
2277 	/* Wait for the CBW to arrive */
2278 	rc = sleep_thread(common, true, bh);
2279 	if (rc)
2280 		return rc;
2281 
2282 	rc = fsg_is_set(common) ? received_cbw(common->fsg, bh) : -EIO;
2283 	bh->state = BUF_STATE_EMPTY;
2284 
2285 	return rc;
2286 }
2287 
2288 
2289 /*-------------------------------------------------------------------------*/
2290 
2291 static int alloc_request(struct fsg_common *common, struct usb_ep *ep,
2292 		struct usb_request **preq)
2293 {
2294 	*preq = usb_ep_alloc_request(ep, GFP_ATOMIC);
2295 	if (*preq)
2296 		return 0;
2297 	ERROR(common, "can't allocate request for %s\n", ep->name);
2298 	return -ENOMEM;
2299 }
2300 
2301 /* Reset interface setting and re-init endpoint state (toggle etc). */
2302 static int do_set_interface(struct fsg_common *common, struct fsg_dev *new_fsg)
2303 {
2304 	struct fsg_dev *fsg;
2305 	int i, rc = 0;
2306 
2307 	if (common->running)
2308 		DBG(common, "reset interface\n");
2309 
2310 reset:
2311 	/* Deallocate the requests */
2312 	if (common->fsg) {
2313 		fsg = common->fsg;
2314 
2315 		for (i = 0; i < common->fsg_num_buffers; ++i) {
2316 			struct fsg_buffhd *bh = &common->buffhds[i];
2317 
2318 			if (bh->inreq) {
2319 				usb_ep_free_request(fsg->bulk_in, bh->inreq);
2320 				bh->inreq = NULL;
2321 			}
2322 			if (bh->outreq) {
2323 				usb_ep_free_request(fsg->bulk_out, bh->outreq);
2324 				bh->outreq = NULL;
2325 			}
2326 		}
2327 
2328 		/* Disable the endpoints */
2329 		if (fsg->bulk_in_enabled) {
2330 			usb_ep_disable(fsg->bulk_in);
2331 			fsg->bulk_in_enabled = 0;
2332 		}
2333 		if (fsg->bulk_out_enabled) {
2334 			usb_ep_disable(fsg->bulk_out);
2335 			fsg->bulk_out_enabled = 0;
2336 		}
2337 
2338 		common->fsg = NULL;
2339 		wake_up(&common->fsg_wait);
2340 	}
2341 
2342 	common->running = 0;
2343 	if (!new_fsg || rc)
2344 		return rc;
2345 
2346 	common->fsg = new_fsg;
2347 	fsg = common->fsg;
2348 
2349 	/* Enable the endpoints */
2350 	rc = config_ep_by_speed(common->gadget, &(fsg->function), fsg->bulk_in);
2351 	if (rc)
2352 		goto reset;
2353 	rc = usb_ep_enable(fsg->bulk_in);
2354 	if (rc)
2355 		goto reset;
2356 	fsg->bulk_in->driver_data = common;
2357 	fsg->bulk_in_enabled = 1;
2358 
2359 	rc = config_ep_by_speed(common->gadget, &(fsg->function),
2360 				fsg->bulk_out);
2361 	if (rc)
2362 		goto reset;
2363 	rc = usb_ep_enable(fsg->bulk_out);
2364 	if (rc)
2365 		goto reset;
2366 	fsg->bulk_out->driver_data = common;
2367 	fsg->bulk_out_enabled = 1;
2368 	common->bulk_out_maxpacket = usb_endpoint_maxp(fsg->bulk_out->desc);
2369 	clear_bit(IGNORE_BULK_OUT, &fsg->atomic_bitflags);
2370 
2371 	/* Allocate the requests */
2372 	for (i = 0; i < common->fsg_num_buffers; ++i) {
2373 		struct fsg_buffhd	*bh = &common->buffhds[i];
2374 
2375 		rc = alloc_request(common, fsg->bulk_in, &bh->inreq);
2376 		if (rc)
2377 			goto reset;
2378 		rc = alloc_request(common, fsg->bulk_out, &bh->outreq);
2379 		if (rc)
2380 			goto reset;
2381 		bh->inreq->buf = bh->outreq->buf = bh->buf;
2382 		bh->inreq->context = bh->outreq->context = bh;
2383 		bh->inreq->complete = bulk_in_complete;
2384 		bh->outreq->complete = bulk_out_complete;
2385 	}
2386 
2387 	common->running = 1;
2388 	for (i = 0; i < ARRAY_SIZE(common->luns); ++i)
2389 		if (common->luns[i])
2390 			common->luns[i]->unit_attention_data =
2391 				SS_RESET_OCCURRED;
2392 	return rc;
2393 }
2394 
2395 
2396 /****************************** ALT CONFIGS ******************************/
2397 
2398 static int fsg_set_alt(struct usb_function *f, unsigned intf, unsigned alt)
2399 {
2400 	struct fsg_dev *fsg = fsg_from_func(f);
2401 
2402 	__raise_exception(fsg->common, FSG_STATE_CONFIG_CHANGE, fsg);
2403 	return USB_GADGET_DELAYED_STATUS;
2404 }
2405 
2406 static void fsg_disable(struct usb_function *f)
2407 {
2408 	struct fsg_dev *fsg = fsg_from_func(f);
2409 
2410 	/* Disable the endpoints */
2411 	if (fsg->bulk_in_enabled) {
2412 		usb_ep_disable(fsg->bulk_in);
2413 		fsg->bulk_in_enabled = 0;
2414 	}
2415 	if (fsg->bulk_out_enabled) {
2416 		usb_ep_disable(fsg->bulk_out);
2417 		fsg->bulk_out_enabled = 0;
2418 	}
2419 
2420 	__raise_exception(fsg->common, FSG_STATE_CONFIG_CHANGE, NULL);
2421 }
2422 
2423 
2424 /*-------------------------------------------------------------------------*/
2425 
2426 static void handle_exception(struct fsg_common *common)
2427 {
2428 	int			i;
2429 	struct fsg_buffhd	*bh;
2430 	enum fsg_state		old_state;
2431 	struct fsg_lun		*curlun;
2432 	unsigned int		exception_req_tag;
2433 	struct fsg_dev		*new_fsg;
2434 
2435 	/*
2436 	 * Clear the existing signals.  Anything but SIGUSR1 is converted
2437 	 * into a high-priority EXIT exception.
2438 	 */
2439 	for (;;) {
2440 		int sig = kernel_dequeue_signal();
2441 		if (!sig)
2442 			break;
2443 		if (sig != SIGUSR1) {
2444 			spin_lock_irq(&common->lock);
2445 			if (common->state < FSG_STATE_EXIT)
2446 				DBG(common, "Main thread exiting on signal\n");
2447 			common->state = FSG_STATE_EXIT;
2448 			spin_unlock_irq(&common->lock);
2449 		}
2450 	}
2451 
2452 	/* Cancel all the pending transfers */
2453 	if (likely(common->fsg)) {
2454 		for (i = 0; i < common->fsg_num_buffers; ++i) {
2455 			bh = &common->buffhds[i];
2456 			if (bh->state == BUF_STATE_SENDING)
2457 				usb_ep_dequeue(common->fsg->bulk_in, bh->inreq);
2458 			if (bh->state == BUF_STATE_RECEIVING)
2459 				usb_ep_dequeue(common->fsg->bulk_out,
2460 					       bh->outreq);
2461 
2462 			/* Wait for a transfer to become idle */
2463 			if (sleep_thread(common, false, bh))
2464 				return;
2465 		}
2466 
2467 		/* Clear out the controller's fifos */
2468 		if (common->fsg->bulk_in_enabled)
2469 			usb_ep_fifo_flush(common->fsg->bulk_in);
2470 		if (common->fsg->bulk_out_enabled)
2471 			usb_ep_fifo_flush(common->fsg->bulk_out);
2472 	}
2473 
2474 	/*
2475 	 * Reset the I/O buffer states and pointers, the SCSI
2476 	 * state, and the exception.  Then invoke the handler.
2477 	 */
2478 	spin_lock_irq(&common->lock);
2479 
2480 	for (i = 0; i < common->fsg_num_buffers; ++i) {
2481 		bh = &common->buffhds[i];
2482 		bh->state = BUF_STATE_EMPTY;
2483 	}
2484 	common->next_buffhd_to_fill = &common->buffhds[0];
2485 	common->next_buffhd_to_drain = &common->buffhds[0];
2486 	exception_req_tag = common->exception_req_tag;
2487 	new_fsg = common->exception_arg;
2488 	old_state = common->state;
2489 	common->state = FSG_STATE_NORMAL;
2490 
2491 	if (old_state != FSG_STATE_ABORT_BULK_OUT) {
2492 		for (i = 0; i < ARRAY_SIZE(common->luns); ++i) {
2493 			curlun = common->luns[i];
2494 			if (!curlun)
2495 				continue;
2496 			curlun->prevent_medium_removal = 0;
2497 			curlun->sense_data = SS_NO_SENSE;
2498 			curlun->unit_attention_data = SS_NO_SENSE;
2499 			curlun->sense_data_info = 0;
2500 			curlun->info_valid = 0;
2501 		}
2502 	}
2503 	spin_unlock_irq(&common->lock);
2504 
2505 	/* Carry out any extra actions required for the exception */
2506 	switch (old_state) {
2507 	case FSG_STATE_NORMAL:
2508 		break;
2509 
2510 	case FSG_STATE_ABORT_BULK_OUT:
2511 		send_status(common);
2512 		break;
2513 
2514 	case FSG_STATE_PROTOCOL_RESET:
2515 		/*
2516 		 * In case we were forced against our will to halt a
2517 		 * bulk endpoint, clear the halt now.  (The SuperH UDC
2518 		 * requires this.)
2519 		 */
2520 		if (!fsg_is_set(common))
2521 			break;
2522 		if (test_and_clear_bit(IGNORE_BULK_OUT,
2523 				       &common->fsg->atomic_bitflags))
2524 			usb_ep_clear_halt(common->fsg->bulk_in);
2525 
2526 		if (common->ep0_req_tag == exception_req_tag)
2527 			ep0_queue(common);	/* Complete the status stage */
2528 
2529 		/*
2530 		 * Technically this should go here, but it would only be
2531 		 * a waste of time.  Ditto for the INTERFACE_CHANGE and
2532 		 * CONFIG_CHANGE cases.
2533 		 */
2534 		/* for (i = 0; i < common->ARRAY_SIZE(common->luns); ++i) */
2535 		/*	if (common->luns[i]) */
2536 		/*		common->luns[i]->unit_attention_data = */
2537 		/*			SS_RESET_OCCURRED;  */
2538 		break;
2539 
2540 	case FSG_STATE_CONFIG_CHANGE:
2541 		do_set_interface(common, new_fsg);
2542 		if (new_fsg)
2543 			usb_composite_setup_continue(common->cdev);
2544 		break;
2545 
2546 	case FSG_STATE_EXIT:
2547 		do_set_interface(common, NULL);		/* Free resources */
2548 		spin_lock_irq(&common->lock);
2549 		common->state = FSG_STATE_TERMINATED;	/* Stop the thread */
2550 		spin_unlock_irq(&common->lock);
2551 		break;
2552 
2553 	case FSG_STATE_TERMINATED:
2554 		break;
2555 	}
2556 }
2557 
2558 
2559 /*-------------------------------------------------------------------------*/
2560 
2561 static int fsg_main_thread(void *common_)
2562 {
2563 	struct fsg_common	*common = common_;
2564 	int			i;
2565 
2566 	/*
2567 	 * Allow the thread to be killed by a signal, but set the signal mask
2568 	 * to block everything but INT, TERM, KILL, and USR1.
2569 	 */
2570 	allow_signal(SIGINT);
2571 	allow_signal(SIGTERM);
2572 	allow_signal(SIGKILL);
2573 	allow_signal(SIGUSR1);
2574 
2575 	/* Allow the thread to be frozen */
2576 	set_freezable();
2577 
2578 	/* The main loop */
2579 	while (common->state != FSG_STATE_TERMINATED) {
2580 		if (exception_in_progress(common) || signal_pending(current)) {
2581 			handle_exception(common);
2582 			continue;
2583 		}
2584 
2585 		if (!common->running) {
2586 			sleep_thread(common, true, NULL);
2587 			continue;
2588 		}
2589 
2590 		if (get_next_command(common) || exception_in_progress(common))
2591 			continue;
2592 		if (do_scsi_command(common) || exception_in_progress(common))
2593 			continue;
2594 		if (finish_reply(common) || exception_in_progress(common))
2595 			continue;
2596 		send_status(common);
2597 	}
2598 
2599 	spin_lock_irq(&common->lock);
2600 	common->thread_task = NULL;
2601 	spin_unlock_irq(&common->lock);
2602 
2603 	/* Eject media from all LUNs */
2604 
2605 	down_write(&common->filesem);
2606 	for (i = 0; i < ARRAY_SIZE(common->luns); i++) {
2607 		struct fsg_lun *curlun = common->luns[i];
2608 
2609 		if (curlun && fsg_lun_is_open(curlun))
2610 			fsg_lun_close(curlun);
2611 	}
2612 	up_write(&common->filesem);
2613 
2614 	/* Let fsg_unbind() know the thread has exited */
2615 	kthread_complete_and_exit(&common->thread_notifier, 0);
2616 }
2617 
2618 
2619 /*************************** DEVICE ATTRIBUTES ***************************/
2620 
2621 static ssize_t ro_show(struct device *dev, struct device_attribute *attr, char *buf)
2622 {
2623 	struct fsg_lun		*curlun = fsg_lun_from_dev(dev);
2624 
2625 	return fsg_show_ro(curlun, buf);
2626 }
2627 
2628 static ssize_t nofua_show(struct device *dev, struct device_attribute *attr,
2629 			  char *buf)
2630 {
2631 	struct fsg_lun		*curlun = fsg_lun_from_dev(dev);
2632 
2633 	return fsg_show_nofua(curlun, buf);
2634 }
2635 
2636 static ssize_t file_show(struct device *dev, struct device_attribute *attr,
2637 			 char *buf)
2638 {
2639 	struct fsg_lun		*curlun = fsg_lun_from_dev(dev);
2640 	struct rw_semaphore	*filesem = dev_get_drvdata(dev);
2641 
2642 	return fsg_show_file(curlun, filesem, buf);
2643 }
2644 
2645 static ssize_t ro_store(struct device *dev, struct device_attribute *attr,
2646 			const char *buf, size_t count)
2647 {
2648 	struct fsg_lun		*curlun = fsg_lun_from_dev(dev);
2649 	struct rw_semaphore	*filesem = dev_get_drvdata(dev);
2650 
2651 	return fsg_store_ro(curlun, filesem, buf, count);
2652 }
2653 
2654 static ssize_t nofua_store(struct device *dev, struct device_attribute *attr,
2655 			   const char *buf, size_t count)
2656 {
2657 	struct fsg_lun		*curlun = fsg_lun_from_dev(dev);
2658 
2659 	return fsg_store_nofua(curlun, buf, count);
2660 }
2661 
2662 static ssize_t file_store(struct device *dev, struct device_attribute *attr,
2663 			  const char *buf, size_t count)
2664 {
2665 	struct fsg_lun		*curlun = fsg_lun_from_dev(dev);
2666 	struct rw_semaphore	*filesem = dev_get_drvdata(dev);
2667 
2668 	return fsg_store_file(curlun, filesem, buf, count);
2669 }
2670 
2671 static ssize_t forced_eject_store(struct device *dev,
2672 				  struct device_attribute *attr,
2673 				  const char *buf, size_t count)
2674 {
2675 	struct fsg_lun		*curlun = fsg_lun_from_dev(dev);
2676 	struct rw_semaphore	*filesem = dev_get_drvdata(dev);
2677 
2678 	return fsg_store_forced_eject(curlun, filesem, buf, count);
2679 }
2680 
2681 static DEVICE_ATTR_RW(nofua);
2682 static DEVICE_ATTR_WO(forced_eject);
2683 
2684 /*
2685  * Mode of the ro and file attribute files will be overridden in
2686  * fsg_lun_dev_is_visible() depending on if this is a cdrom, or if it is a
2687  * removable device.
2688  */
2689 static DEVICE_ATTR_RW(ro);
2690 static DEVICE_ATTR_RW(file);
2691 
2692 /****************************** FSG COMMON ******************************/
2693 
2694 static void fsg_lun_release(struct device *dev)
2695 {
2696 	/* Nothing needs to be done */
2697 }
2698 
2699 static struct fsg_common *fsg_common_setup(struct fsg_common *common)
2700 {
2701 	if (!common) {
2702 		common = kzalloc(sizeof(*common), GFP_KERNEL);
2703 		if (!common)
2704 			return ERR_PTR(-ENOMEM);
2705 		common->free_storage_on_release = 1;
2706 	} else {
2707 		common->free_storage_on_release = 0;
2708 	}
2709 	init_rwsem(&common->filesem);
2710 	spin_lock_init(&common->lock);
2711 	init_completion(&common->thread_notifier);
2712 	init_waitqueue_head(&common->io_wait);
2713 	init_waitqueue_head(&common->fsg_wait);
2714 	common->state = FSG_STATE_TERMINATED;
2715 	memset(common->luns, 0, sizeof(common->luns));
2716 
2717 	return common;
2718 }
2719 
2720 void fsg_common_set_sysfs(struct fsg_common *common, bool sysfs)
2721 {
2722 	common->sysfs = sysfs;
2723 }
2724 EXPORT_SYMBOL_GPL(fsg_common_set_sysfs);
2725 
2726 static void _fsg_common_free_buffers(struct fsg_buffhd *buffhds, unsigned n)
2727 {
2728 	if (buffhds) {
2729 		struct fsg_buffhd *bh = buffhds;
2730 		while (n--) {
2731 			kfree(bh->buf);
2732 			++bh;
2733 		}
2734 		kfree(buffhds);
2735 	}
2736 }
2737 
2738 int fsg_common_set_num_buffers(struct fsg_common *common, unsigned int n)
2739 {
2740 	struct fsg_buffhd *bh, *buffhds;
2741 	int i;
2742 
2743 	buffhds = kcalloc(n, sizeof(*buffhds), GFP_KERNEL);
2744 	if (!buffhds)
2745 		return -ENOMEM;
2746 
2747 	/* Data buffers cyclic list */
2748 	bh = buffhds;
2749 	i = n;
2750 	goto buffhds_first_it;
2751 	do {
2752 		bh->next = bh + 1;
2753 		++bh;
2754 buffhds_first_it:
2755 		bh->buf = kmalloc(FSG_BUFLEN, GFP_KERNEL);
2756 		if (unlikely(!bh->buf))
2757 			goto error_release;
2758 	} while (--i);
2759 	bh->next = buffhds;
2760 
2761 	_fsg_common_free_buffers(common->buffhds, common->fsg_num_buffers);
2762 	common->fsg_num_buffers = n;
2763 	common->buffhds = buffhds;
2764 
2765 	return 0;
2766 
2767 error_release:
2768 	/*
2769 	 * "buf"s pointed to by heads after n - i are NULL
2770 	 * so releasing them won't hurt
2771 	 */
2772 	_fsg_common_free_buffers(buffhds, n);
2773 
2774 	return -ENOMEM;
2775 }
2776 EXPORT_SYMBOL_GPL(fsg_common_set_num_buffers);
2777 
2778 void fsg_common_remove_lun(struct fsg_lun *lun)
2779 {
2780 	if (device_is_registered(&lun->dev))
2781 		device_unregister(&lun->dev);
2782 	fsg_lun_close(lun);
2783 	kfree(lun);
2784 }
2785 EXPORT_SYMBOL_GPL(fsg_common_remove_lun);
2786 
2787 static void _fsg_common_remove_luns(struct fsg_common *common, int n)
2788 {
2789 	int i;
2790 
2791 	for (i = 0; i < n; ++i)
2792 		if (common->luns[i]) {
2793 			fsg_common_remove_lun(common->luns[i]);
2794 			common->luns[i] = NULL;
2795 		}
2796 }
2797 
2798 void fsg_common_remove_luns(struct fsg_common *common)
2799 {
2800 	_fsg_common_remove_luns(common, ARRAY_SIZE(common->luns));
2801 }
2802 EXPORT_SYMBOL_GPL(fsg_common_remove_luns);
2803 
2804 void fsg_common_free_buffers(struct fsg_common *common)
2805 {
2806 	_fsg_common_free_buffers(common->buffhds, common->fsg_num_buffers);
2807 	common->buffhds = NULL;
2808 }
2809 EXPORT_SYMBOL_GPL(fsg_common_free_buffers);
2810 
2811 int fsg_common_set_cdev(struct fsg_common *common,
2812 			 struct usb_composite_dev *cdev, bool can_stall)
2813 {
2814 	struct usb_string *us;
2815 
2816 	common->gadget = cdev->gadget;
2817 	common->ep0 = cdev->gadget->ep0;
2818 	common->ep0req = cdev->req;
2819 	common->cdev = cdev;
2820 
2821 	us = usb_gstrings_attach(cdev, fsg_strings_array,
2822 				 ARRAY_SIZE(fsg_strings));
2823 	if (IS_ERR(us))
2824 		return PTR_ERR(us);
2825 
2826 	fsg_intf_desc.iInterface = us[FSG_STRING_INTERFACE].id;
2827 
2828 	/*
2829 	 * Some peripheral controllers are known not to be able to
2830 	 * halt bulk endpoints correctly.  If one of them is present,
2831 	 * disable stalls.
2832 	 */
2833 	common->can_stall = can_stall &&
2834 			gadget_is_stall_supported(common->gadget);
2835 
2836 	return 0;
2837 }
2838 EXPORT_SYMBOL_GPL(fsg_common_set_cdev);
2839 
2840 static struct attribute *fsg_lun_dev_attrs[] = {
2841 	&dev_attr_ro.attr,
2842 	&dev_attr_file.attr,
2843 	&dev_attr_nofua.attr,
2844 	&dev_attr_forced_eject.attr,
2845 	NULL
2846 };
2847 
2848 static umode_t fsg_lun_dev_is_visible(struct kobject *kobj,
2849 				      struct attribute *attr, int idx)
2850 {
2851 	struct device *dev = kobj_to_dev(kobj);
2852 	struct fsg_lun *lun = fsg_lun_from_dev(dev);
2853 
2854 	if (attr == &dev_attr_ro.attr)
2855 		return lun->cdrom ? S_IRUGO : (S_IWUSR | S_IRUGO);
2856 	if (attr == &dev_attr_file.attr)
2857 		return lun->removable ? (S_IWUSR | S_IRUGO) : S_IRUGO;
2858 	return attr->mode;
2859 }
2860 
2861 static const struct attribute_group fsg_lun_dev_group = {
2862 	.attrs = fsg_lun_dev_attrs,
2863 	.is_visible = fsg_lun_dev_is_visible,
2864 };
2865 
2866 static const struct attribute_group *fsg_lun_dev_groups[] = {
2867 	&fsg_lun_dev_group,
2868 	NULL
2869 };
2870 
2871 int fsg_common_create_lun(struct fsg_common *common, struct fsg_lun_config *cfg,
2872 			  unsigned int id, const char *name,
2873 			  const char **name_pfx)
2874 {
2875 	struct fsg_lun *lun;
2876 	char *pathbuf = NULL, *p = "(no medium)";
2877 	int rc = -ENOMEM;
2878 
2879 	if (id >= ARRAY_SIZE(common->luns))
2880 		return -ENODEV;
2881 
2882 	if (common->luns[id])
2883 		return -EBUSY;
2884 
2885 	if (!cfg->filename && !cfg->removable) {
2886 		pr_err("no file given for LUN%d\n", id);
2887 		return -EINVAL;
2888 	}
2889 
2890 	lun = kzalloc(sizeof(*lun), GFP_KERNEL);
2891 	if (!lun)
2892 		return -ENOMEM;
2893 
2894 	lun->name_pfx = name_pfx;
2895 
2896 	lun->cdrom = !!cfg->cdrom;
2897 	lun->ro = cfg->cdrom || cfg->ro;
2898 	lun->initially_ro = lun->ro;
2899 	lun->removable = !!cfg->removable;
2900 
2901 	if (!common->sysfs) {
2902 		/* we DON'T own the name!*/
2903 		lun->name = name;
2904 	} else {
2905 		lun->dev.release = fsg_lun_release;
2906 		lun->dev.parent = &common->gadget->dev;
2907 		lun->dev.groups = fsg_lun_dev_groups;
2908 		dev_set_drvdata(&lun->dev, &common->filesem);
2909 		dev_set_name(&lun->dev, "%s", name);
2910 		lun->name = dev_name(&lun->dev);
2911 
2912 		rc = device_register(&lun->dev);
2913 		if (rc) {
2914 			pr_info("failed to register LUN%d: %d\n", id, rc);
2915 			put_device(&lun->dev);
2916 			goto error_sysfs;
2917 		}
2918 	}
2919 
2920 	common->luns[id] = lun;
2921 
2922 	if (cfg->filename) {
2923 		rc = fsg_lun_open(lun, cfg->filename);
2924 		if (rc)
2925 			goto error_lun;
2926 
2927 		p = "(error)";
2928 		pathbuf = kmalloc(PATH_MAX, GFP_KERNEL);
2929 		if (pathbuf) {
2930 			p = file_path(lun->filp, pathbuf, PATH_MAX);
2931 			if (IS_ERR(p))
2932 				p = "(error)";
2933 		}
2934 	}
2935 	pr_info("LUN: %s%s%sfile: %s\n",
2936 	      lun->removable ? "removable " : "",
2937 	      lun->ro ? "read only " : "",
2938 	      lun->cdrom ? "CD-ROM " : "",
2939 	      p);
2940 	kfree(pathbuf);
2941 
2942 	return 0;
2943 
2944 error_lun:
2945 	if (device_is_registered(&lun->dev))
2946 		device_unregister(&lun->dev);
2947 	common->luns[id] = NULL;
2948 error_sysfs:
2949 	kfree(lun);
2950 	return rc;
2951 }
2952 EXPORT_SYMBOL_GPL(fsg_common_create_lun);
2953 
2954 int fsg_common_create_luns(struct fsg_common *common, struct fsg_config *cfg)
2955 {
2956 	char buf[8]; /* enough for 100000000 different numbers, decimal */
2957 	int i, rc;
2958 
2959 	fsg_common_remove_luns(common);
2960 
2961 	for (i = 0; i < cfg->nluns; ++i) {
2962 		snprintf(buf, sizeof(buf), "lun%d", i);
2963 		rc = fsg_common_create_lun(common, &cfg->luns[i], i, buf, NULL);
2964 		if (rc)
2965 			goto fail;
2966 	}
2967 
2968 	pr_info("Number of LUNs=%d\n", cfg->nluns);
2969 
2970 	return 0;
2971 
2972 fail:
2973 	_fsg_common_remove_luns(common, i);
2974 	return rc;
2975 }
2976 EXPORT_SYMBOL_GPL(fsg_common_create_luns);
2977 
2978 void fsg_common_set_inquiry_string(struct fsg_common *common, const char *vn,
2979 				   const char *pn)
2980 {
2981 	int i;
2982 
2983 	/* Prepare inquiryString */
2984 	i = get_default_bcdDevice();
2985 	snprintf(common->inquiry_string, sizeof(common->inquiry_string),
2986 		 "%-8s%-16s%04x", vn ?: "Linux",
2987 		 /* Assume product name dependent on the first LUN */
2988 		 pn ?: ((*common->luns)->cdrom
2989 		     ? "File-CD Gadget"
2990 		     : "File-Stor Gadget"),
2991 		 i);
2992 }
2993 EXPORT_SYMBOL_GPL(fsg_common_set_inquiry_string);
2994 
2995 static void fsg_common_release(struct fsg_common *common)
2996 {
2997 	int i;
2998 
2999 	/* If the thread isn't already dead, tell it to exit now */
3000 	if (common->state != FSG_STATE_TERMINATED) {
3001 		raise_exception(common, FSG_STATE_EXIT);
3002 		wait_for_completion(&common->thread_notifier);
3003 	}
3004 
3005 	for (i = 0; i < ARRAY_SIZE(common->luns); ++i) {
3006 		struct fsg_lun *lun = common->luns[i];
3007 		if (!lun)
3008 			continue;
3009 		fsg_lun_close(lun);
3010 		if (device_is_registered(&lun->dev))
3011 			device_unregister(&lun->dev);
3012 		kfree(lun);
3013 	}
3014 
3015 	_fsg_common_free_buffers(common->buffhds, common->fsg_num_buffers);
3016 	if (common->free_storage_on_release)
3017 		kfree(common);
3018 }
3019 
3020 
3021 /*-------------------------------------------------------------------------*/
3022 
3023 static int fsg_bind(struct usb_configuration *c, struct usb_function *f)
3024 {
3025 	struct fsg_dev		*fsg = fsg_from_func(f);
3026 	struct fsg_common	*common = fsg->common;
3027 	struct usb_gadget	*gadget = c->cdev->gadget;
3028 	int			i;
3029 	struct usb_ep		*ep;
3030 	unsigned		max_burst;
3031 	int			ret;
3032 	struct fsg_opts		*opts;
3033 
3034 	/* Don't allow to bind if we don't have at least one LUN */
3035 	ret = _fsg_common_get_max_lun(common);
3036 	if (ret < 0) {
3037 		pr_err("There should be at least one LUN.\n");
3038 		return -EINVAL;
3039 	}
3040 
3041 	opts = fsg_opts_from_func_inst(f->fi);
3042 	if (!opts->no_configfs) {
3043 		ret = fsg_common_set_cdev(fsg->common, c->cdev,
3044 					  fsg->common->can_stall);
3045 		if (ret)
3046 			return ret;
3047 		fsg_common_set_inquiry_string(fsg->common, NULL, NULL);
3048 	}
3049 
3050 	if (!common->thread_task) {
3051 		common->state = FSG_STATE_NORMAL;
3052 		common->thread_task =
3053 			kthread_create(fsg_main_thread, common, "file-storage");
3054 		if (IS_ERR(common->thread_task)) {
3055 			ret = PTR_ERR(common->thread_task);
3056 			common->thread_task = NULL;
3057 			common->state = FSG_STATE_TERMINATED;
3058 			return ret;
3059 		}
3060 		DBG(common, "I/O thread pid: %d\n",
3061 		    task_pid_nr(common->thread_task));
3062 		wake_up_process(common->thread_task);
3063 	}
3064 
3065 	fsg->gadget = gadget;
3066 
3067 	/* New interface */
3068 	i = usb_interface_id(c, f);
3069 	if (i < 0)
3070 		goto fail;
3071 	fsg_intf_desc.bInterfaceNumber = i;
3072 	fsg->interface_number = i;
3073 
3074 	/* Find all the endpoints we will use */
3075 	ep = usb_ep_autoconfig(gadget, &fsg_fs_bulk_in_desc);
3076 	if (!ep)
3077 		goto autoconf_fail;
3078 	fsg->bulk_in = ep;
3079 
3080 	ep = usb_ep_autoconfig(gadget, &fsg_fs_bulk_out_desc);
3081 	if (!ep)
3082 		goto autoconf_fail;
3083 	fsg->bulk_out = ep;
3084 
3085 	/* Assume endpoint addresses are the same for both speeds */
3086 	fsg_hs_bulk_in_desc.bEndpointAddress =
3087 		fsg_fs_bulk_in_desc.bEndpointAddress;
3088 	fsg_hs_bulk_out_desc.bEndpointAddress =
3089 		fsg_fs_bulk_out_desc.bEndpointAddress;
3090 
3091 	/* Calculate bMaxBurst, we know packet size is 1024 */
3092 	max_burst = min_t(unsigned, FSG_BUFLEN / 1024, 15);
3093 
3094 	fsg_ss_bulk_in_desc.bEndpointAddress =
3095 		fsg_fs_bulk_in_desc.bEndpointAddress;
3096 	fsg_ss_bulk_in_comp_desc.bMaxBurst = max_burst;
3097 
3098 	fsg_ss_bulk_out_desc.bEndpointAddress =
3099 		fsg_fs_bulk_out_desc.bEndpointAddress;
3100 	fsg_ss_bulk_out_comp_desc.bMaxBurst = max_burst;
3101 
3102 	ret = usb_assign_descriptors(f, fsg_fs_function, fsg_hs_function,
3103 			fsg_ss_function, fsg_ss_function);
3104 	if (ret)
3105 		goto autoconf_fail;
3106 
3107 	return 0;
3108 
3109 autoconf_fail:
3110 	ERROR(fsg, "unable to autoconfigure all endpoints\n");
3111 	i = -ENOTSUPP;
3112 fail:
3113 	/* terminate the thread */
3114 	if (fsg->common->state != FSG_STATE_TERMINATED) {
3115 		raise_exception(fsg->common, FSG_STATE_EXIT);
3116 		wait_for_completion(&fsg->common->thread_notifier);
3117 	}
3118 	return i;
3119 }
3120 
3121 /****************************** ALLOCATE FUNCTION *************************/
3122 
3123 static void fsg_unbind(struct usb_configuration *c, struct usb_function *f)
3124 {
3125 	struct fsg_dev		*fsg = fsg_from_func(f);
3126 	struct fsg_common	*common = fsg->common;
3127 
3128 	DBG(fsg, "unbind\n");
3129 	if (fsg->common->fsg == fsg) {
3130 		__raise_exception(fsg->common, FSG_STATE_CONFIG_CHANGE, NULL);
3131 		/* FIXME: make interruptible or killable somehow? */
3132 		wait_event(common->fsg_wait, common->fsg != fsg);
3133 	}
3134 
3135 	usb_free_all_descriptors(&fsg->function);
3136 }
3137 
3138 static inline struct fsg_lun_opts *to_fsg_lun_opts(struct config_item *item)
3139 {
3140 	return container_of(to_config_group(item), struct fsg_lun_opts, group);
3141 }
3142 
3143 static inline struct fsg_opts *to_fsg_opts(struct config_item *item)
3144 {
3145 	return container_of(to_config_group(item), struct fsg_opts,
3146 			    func_inst.group);
3147 }
3148 
3149 static void fsg_lun_attr_release(struct config_item *item)
3150 {
3151 	struct fsg_lun_opts *lun_opts;
3152 
3153 	lun_opts = to_fsg_lun_opts(item);
3154 	kfree(lun_opts);
3155 }
3156 
3157 static struct configfs_item_operations fsg_lun_item_ops = {
3158 	.release		= fsg_lun_attr_release,
3159 };
3160 
3161 static ssize_t fsg_lun_opts_file_show(struct config_item *item, char *page)
3162 {
3163 	struct fsg_lun_opts *opts = to_fsg_lun_opts(item);
3164 	struct fsg_opts *fsg_opts = to_fsg_opts(opts->group.cg_item.ci_parent);
3165 
3166 	return fsg_show_file(opts->lun, &fsg_opts->common->filesem, page);
3167 }
3168 
3169 static ssize_t fsg_lun_opts_file_store(struct config_item *item,
3170 				       const char *page, size_t len)
3171 {
3172 	struct fsg_lun_opts *opts = to_fsg_lun_opts(item);
3173 	struct fsg_opts *fsg_opts = to_fsg_opts(opts->group.cg_item.ci_parent);
3174 
3175 	return fsg_store_file(opts->lun, &fsg_opts->common->filesem, page, len);
3176 }
3177 
3178 CONFIGFS_ATTR(fsg_lun_opts_, file);
3179 
3180 static ssize_t fsg_lun_opts_ro_show(struct config_item *item, char *page)
3181 {
3182 	return fsg_show_ro(to_fsg_lun_opts(item)->lun, page);
3183 }
3184 
3185 static ssize_t fsg_lun_opts_ro_store(struct config_item *item,
3186 				       const char *page, size_t len)
3187 {
3188 	struct fsg_lun_opts *opts = to_fsg_lun_opts(item);
3189 	struct fsg_opts *fsg_opts = to_fsg_opts(opts->group.cg_item.ci_parent);
3190 
3191 	return fsg_store_ro(opts->lun, &fsg_opts->common->filesem, page, len);
3192 }
3193 
3194 CONFIGFS_ATTR(fsg_lun_opts_, ro);
3195 
3196 static ssize_t fsg_lun_opts_removable_show(struct config_item *item,
3197 					   char *page)
3198 {
3199 	return fsg_show_removable(to_fsg_lun_opts(item)->lun, page);
3200 }
3201 
3202 static ssize_t fsg_lun_opts_removable_store(struct config_item *item,
3203 				       const char *page, size_t len)
3204 {
3205 	return fsg_store_removable(to_fsg_lun_opts(item)->lun, page, len);
3206 }
3207 
3208 CONFIGFS_ATTR(fsg_lun_opts_, removable);
3209 
3210 static ssize_t fsg_lun_opts_cdrom_show(struct config_item *item, char *page)
3211 {
3212 	return fsg_show_cdrom(to_fsg_lun_opts(item)->lun, page);
3213 }
3214 
3215 static ssize_t fsg_lun_opts_cdrom_store(struct config_item *item,
3216 				       const char *page, size_t len)
3217 {
3218 	struct fsg_lun_opts *opts = to_fsg_lun_opts(item);
3219 	struct fsg_opts *fsg_opts = to_fsg_opts(opts->group.cg_item.ci_parent);
3220 
3221 	return fsg_store_cdrom(opts->lun, &fsg_opts->common->filesem, page,
3222 			       len);
3223 }
3224 
3225 CONFIGFS_ATTR(fsg_lun_opts_, cdrom);
3226 
3227 static ssize_t fsg_lun_opts_nofua_show(struct config_item *item, char *page)
3228 {
3229 	return fsg_show_nofua(to_fsg_lun_opts(item)->lun, page);
3230 }
3231 
3232 static ssize_t fsg_lun_opts_nofua_store(struct config_item *item,
3233 				       const char *page, size_t len)
3234 {
3235 	return fsg_store_nofua(to_fsg_lun_opts(item)->lun, page, len);
3236 }
3237 
3238 CONFIGFS_ATTR(fsg_lun_opts_, nofua);
3239 
3240 static ssize_t fsg_lun_opts_inquiry_string_show(struct config_item *item,
3241 						char *page)
3242 {
3243 	return fsg_show_inquiry_string(to_fsg_lun_opts(item)->lun, page);
3244 }
3245 
3246 static ssize_t fsg_lun_opts_inquiry_string_store(struct config_item *item,
3247 						 const char *page, size_t len)
3248 {
3249 	return fsg_store_inquiry_string(to_fsg_lun_opts(item)->lun, page, len);
3250 }
3251 
3252 CONFIGFS_ATTR(fsg_lun_opts_, inquiry_string);
3253 
3254 static ssize_t fsg_lun_opts_forced_eject_store(struct config_item *item,
3255 					       const char *page, size_t len)
3256 {
3257 	struct fsg_lun_opts *opts = to_fsg_lun_opts(item);
3258 	struct fsg_opts *fsg_opts = to_fsg_opts(opts->group.cg_item.ci_parent);
3259 
3260 	return fsg_store_forced_eject(opts->lun, &fsg_opts->common->filesem,
3261 				      page, len);
3262 }
3263 
3264 CONFIGFS_ATTR_WO(fsg_lun_opts_, forced_eject);
3265 
3266 static struct configfs_attribute *fsg_lun_attrs[] = {
3267 	&fsg_lun_opts_attr_file,
3268 	&fsg_lun_opts_attr_ro,
3269 	&fsg_lun_opts_attr_removable,
3270 	&fsg_lun_opts_attr_cdrom,
3271 	&fsg_lun_opts_attr_nofua,
3272 	&fsg_lun_opts_attr_inquiry_string,
3273 	&fsg_lun_opts_attr_forced_eject,
3274 	NULL,
3275 };
3276 
3277 static const struct config_item_type fsg_lun_type = {
3278 	.ct_item_ops	= &fsg_lun_item_ops,
3279 	.ct_attrs	= fsg_lun_attrs,
3280 	.ct_owner	= THIS_MODULE,
3281 };
3282 
3283 static struct config_group *fsg_lun_make(struct config_group *group,
3284 					 const char *name)
3285 {
3286 	struct fsg_lun_opts *opts;
3287 	struct fsg_opts *fsg_opts;
3288 	struct fsg_lun_config config;
3289 	char *num_str;
3290 	u8 num;
3291 	int ret;
3292 
3293 	num_str = strchr(name, '.');
3294 	if (!num_str) {
3295 		pr_err("Unable to locate . in LUN.NUMBER\n");
3296 		return ERR_PTR(-EINVAL);
3297 	}
3298 	num_str++;
3299 
3300 	ret = kstrtou8(num_str, 0, &num);
3301 	if (ret)
3302 		return ERR_PTR(ret);
3303 
3304 	fsg_opts = to_fsg_opts(&group->cg_item);
3305 	if (num >= FSG_MAX_LUNS)
3306 		return ERR_PTR(-ERANGE);
3307 	num = array_index_nospec(num, FSG_MAX_LUNS);
3308 
3309 	mutex_lock(&fsg_opts->lock);
3310 	if (fsg_opts->refcnt || fsg_opts->common->luns[num]) {
3311 		ret = -EBUSY;
3312 		goto out;
3313 	}
3314 
3315 	opts = kzalloc(sizeof(*opts), GFP_KERNEL);
3316 	if (!opts) {
3317 		ret = -ENOMEM;
3318 		goto out;
3319 	}
3320 
3321 	memset(&config, 0, sizeof(config));
3322 	config.removable = true;
3323 
3324 	ret = fsg_common_create_lun(fsg_opts->common, &config, num, name,
3325 				    (const char **)&group->cg_item.ci_name);
3326 	if (ret) {
3327 		kfree(opts);
3328 		goto out;
3329 	}
3330 	opts->lun = fsg_opts->common->luns[num];
3331 	opts->lun_id = num;
3332 	mutex_unlock(&fsg_opts->lock);
3333 
3334 	config_group_init_type_name(&opts->group, name, &fsg_lun_type);
3335 
3336 	return &opts->group;
3337 out:
3338 	mutex_unlock(&fsg_opts->lock);
3339 	return ERR_PTR(ret);
3340 }
3341 
3342 static void fsg_lun_drop(struct config_group *group, struct config_item *item)
3343 {
3344 	struct fsg_lun_opts *lun_opts;
3345 	struct fsg_opts *fsg_opts;
3346 
3347 	lun_opts = to_fsg_lun_opts(item);
3348 	fsg_opts = to_fsg_opts(&group->cg_item);
3349 
3350 	mutex_lock(&fsg_opts->lock);
3351 	if (fsg_opts->refcnt) {
3352 		struct config_item *gadget;
3353 
3354 		gadget = group->cg_item.ci_parent->ci_parent;
3355 		unregister_gadget_item(gadget);
3356 	}
3357 
3358 	fsg_common_remove_lun(lun_opts->lun);
3359 	fsg_opts->common->luns[lun_opts->lun_id] = NULL;
3360 	lun_opts->lun_id = 0;
3361 	mutex_unlock(&fsg_opts->lock);
3362 
3363 	config_item_put(item);
3364 }
3365 
3366 static void fsg_attr_release(struct config_item *item)
3367 {
3368 	struct fsg_opts *opts = to_fsg_opts(item);
3369 
3370 	usb_put_function_instance(&opts->func_inst);
3371 }
3372 
3373 static struct configfs_item_operations fsg_item_ops = {
3374 	.release		= fsg_attr_release,
3375 };
3376 
3377 static ssize_t fsg_opts_stall_show(struct config_item *item, char *page)
3378 {
3379 	struct fsg_opts *opts = to_fsg_opts(item);
3380 	int result;
3381 
3382 	mutex_lock(&opts->lock);
3383 	result = sprintf(page, "%d", opts->common->can_stall);
3384 	mutex_unlock(&opts->lock);
3385 
3386 	return result;
3387 }
3388 
3389 static ssize_t fsg_opts_stall_store(struct config_item *item, const char *page,
3390 				    size_t len)
3391 {
3392 	struct fsg_opts *opts = to_fsg_opts(item);
3393 	int ret;
3394 	bool stall;
3395 
3396 	mutex_lock(&opts->lock);
3397 
3398 	if (opts->refcnt) {
3399 		mutex_unlock(&opts->lock);
3400 		return -EBUSY;
3401 	}
3402 
3403 	ret = kstrtobool(page, &stall);
3404 	if (!ret) {
3405 		opts->common->can_stall = stall;
3406 		ret = len;
3407 	}
3408 
3409 	mutex_unlock(&opts->lock);
3410 
3411 	return ret;
3412 }
3413 
3414 CONFIGFS_ATTR(fsg_opts_, stall);
3415 
3416 #ifdef CONFIG_USB_GADGET_DEBUG_FILES
3417 static ssize_t fsg_opts_num_buffers_show(struct config_item *item, char *page)
3418 {
3419 	struct fsg_opts *opts = to_fsg_opts(item);
3420 	int result;
3421 
3422 	mutex_lock(&opts->lock);
3423 	result = sprintf(page, "%d", opts->common->fsg_num_buffers);
3424 	mutex_unlock(&opts->lock);
3425 
3426 	return result;
3427 }
3428 
3429 static ssize_t fsg_opts_num_buffers_store(struct config_item *item,
3430 					  const char *page, size_t len)
3431 {
3432 	struct fsg_opts *opts = to_fsg_opts(item);
3433 	int ret;
3434 	u8 num;
3435 
3436 	mutex_lock(&opts->lock);
3437 	if (opts->refcnt) {
3438 		ret = -EBUSY;
3439 		goto end;
3440 	}
3441 	ret = kstrtou8(page, 0, &num);
3442 	if (ret)
3443 		goto end;
3444 
3445 	ret = fsg_common_set_num_buffers(opts->common, num);
3446 	if (ret)
3447 		goto end;
3448 	ret = len;
3449 
3450 end:
3451 	mutex_unlock(&opts->lock);
3452 	return ret;
3453 }
3454 
3455 CONFIGFS_ATTR(fsg_opts_, num_buffers);
3456 #endif
3457 
3458 static struct configfs_attribute *fsg_attrs[] = {
3459 	&fsg_opts_attr_stall,
3460 #ifdef CONFIG_USB_GADGET_DEBUG_FILES
3461 	&fsg_opts_attr_num_buffers,
3462 #endif
3463 	NULL,
3464 };
3465 
3466 static struct configfs_group_operations fsg_group_ops = {
3467 	.make_group	= fsg_lun_make,
3468 	.drop_item	= fsg_lun_drop,
3469 };
3470 
3471 static const struct config_item_type fsg_func_type = {
3472 	.ct_item_ops	= &fsg_item_ops,
3473 	.ct_group_ops	= &fsg_group_ops,
3474 	.ct_attrs	= fsg_attrs,
3475 	.ct_owner	= THIS_MODULE,
3476 };
3477 
3478 static void fsg_free_inst(struct usb_function_instance *fi)
3479 {
3480 	struct fsg_opts *opts;
3481 
3482 	opts = fsg_opts_from_func_inst(fi);
3483 	fsg_common_release(opts->common);
3484 	kfree(opts);
3485 }
3486 
3487 static struct usb_function_instance *fsg_alloc_inst(void)
3488 {
3489 	struct fsg_opts *opts;
3490 	struct fsg_lun_config config;
3491 	int rc;
3492 
3493 	opts = kzalloc(sizeof(*opts), GFP_KERNEL);
3494 	if (!opts)
3495 		return ERR_PTR(-ENOMEM);
3496 	mutex_init(&opts->lock);
3497 	opts->func_inst.free_func_inst = fsg_free_inst;
3498 	opts->common = fsg_common_setup(opts->common);
3499 	if (IS_ERR(opts->common)) {
3500 		rc = PTR_ERR(opts->common);
3501 		goto release_opts;
3502 	}
3503 
3504 	rc = fsg_common_set_num_buffers(opts->common,
3505 					CONFIG_USB_GADGET_STORAGE_NUM_BUFFERS);
3506 	if (rc)
3507 		goto release_common;
3508 
3509 	pr_info(FSG_DRIVER_DESC ", version: " FSG_DRIVER_VERSION "\n");
3510 
3511 	memset(&config, 0, sizeof(config));
3512 	config.removable = true;
3513 	rc = fsg_common_create_lun(opts->common, &config, 0, "lun.0",
3514 			(const char **)&opts->func_inst.group.cg_item.ci_name);
3515 	if (rc)
3516 		goto release_buffers;
3517 
3518 	opts->lun0.lun = opts->common->luns[0];
3519 	opts->lun0.lun_id = 0;
3520 
3521 	config_group_init_type_name(&opts->func_inst.group, "", &fsg_func_type);
3522 
3523 	config_group_init_type_name(&opts->lun0.group, "lun.0", &fsg_lun_type);
3524 	configfs_add_default_group(&opts->lun0.group, &opts->func_inst.group);
3525 
3526 	return &opts->func_inst;
3527 
3528 release_buffers:
3529 	fsg_common_free_buffers(opts->common);
3530 release_common:
3531 	kfree(opts->common);
3532 release_opts:
3533 	kfree(opts);
3534 	return ERR_PTR(rc);
3535 }
3536 
3537 static void fsg_free(struct usb_function *f)
3538 {
3539 	struct fsg_dev *fsg;
3540 	struct fsg_opts *opts;
3541 
3542 	fsg = container_of(f, struct fsg_dev, function);
3543 	opts = container_of(f->fi, struct fsg_opts, func_inst);
3544 
3545 	mutex_lock(&opts->lock);
3546 	opts->refcnt--;
3547 	mutex_unlock(&opts->lock);
3548 
3549 	kfree(fsg);
3550 }
3551 
3552 static struct usb_function *fsg_alloc(struct usb_function_instance *fi)
3553 {
3554 	struct fsg_opts *opts = fsg_opts_from_func_inst(fi);
3555 	struct fsg_common *common = opts->common;
3556 	struct fsg_dev *fsg;
3557 
3558 	fsg = kzalloc(sizeof(*fsg), GFP_KERNEL);
3559 	if (unlikely(!fsg))
3560 		return ERR_PTR(-ENOMEM);
3561 
3562 	mutex_lock(&opts->lock);
3563 	opts->refcnt++;
3564 	mutex_unlock(&opts->lock);
3565 
3566 	fsg->function.name	= FSG_DRIVER_DESC;
3567 	fsg->function.bind	= fsg_bind;
3568 	fsg->function.unbind	= fsg_unbind;
3569 	fsg->function.setup	= fsg_setup;
3570 	fsg->function.set_alt	= fsg_set_alt;
3571 	fsg->function.disable	= fsg_disable;
3572 	fsg->function.free_func	= fsg_free;
3573 
3574 	fsg->common               = common;
3575 
3576 	return &fsg->function;
3577 }
3578 
3579 DECLARE_USB_FUNCTION_INIT(mass_storage, fsg_alloc_inst, fsg_alloc);
3580 MODULE_LICENSE("GPL");
3581 MODULE_AUTHOR("Michal Nazarewicz");
3582 
3583 /************************* Module parameters *************************/
3584 
3585 
3586 void fsg_config_from_params(struct fsg_config *cfg,
3587 		       const struct fsg_module_parameters *params,
3588 		       unsigned int fsg_num_buffers)
3589 {
3590 	struct fsg_lun_config *lun;
3591 	unsigned i;
3592 
3593 	/* Configure LUNs */
3594 	cfg->nluns =
3595 		min(params->luns ?: (params->file_count ?: 1u),
3596 		    (unsigned)FSG_MAX_LUNS);
3597 	for (i = 0, lun = cfg->luns; i < cfg->nluns; ++i, ++lun) {
3598 		lun->ro = !!params->ro[i];
3599 		lun->cdrom = !!params->cdrom[i];
3600 		lun->removable = !!params->removable[i];
3601 		lun->filename =
3602 			params->file_count > i && params->file[i][0]
3603 			? params->file[i]
3604 			: NULL;
3605 	}
3606 
3607 	/* Let MSF use defaults */
3608 	cfg->vendor_name = NULL;
3609 	cfg->product_name = NULL;
3610 
3611 	cfg->ops = NULL;
3612 	cfg->private_data = NULL;
3613 
3614 	/* Finalise */
3615 	cfg->can_stall = params->stall;
3616 	cfg->fsg_num_buffers = fsg_num_buffers;
3617 }
3618 EXPORT_SYMBOL_GPL(fsg_config_from_params);
3619