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