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