xref: /openbmc/linux/drivers/scsi/scsi_lib.c (revision 37e14dbe)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Copyright (C) 1999 Eric Youngdale
4  * Copyright (C) 2014 Christoph Hellwig
5  *
6  *  SCSI queueing library.
7  *      Initial versions: Eric Youngdale (eric@andante.org).
8  *                        Based upon conversations with large numbers
9  *                        of people at Linux Expo.
10  */
11 
12 #include <linux/bio.h>
13 #include <linux/bitops.h>
14 #include <linux/blkdev.h>
15 #include <linux/completion.h>
16 #include <linux/kernel.h>
17 #include <linux/export.h>
18 #include <linux/init.h>
19 #include <linux/pci.h>
20 #include <linux/delay.h>
21 #include <linux/hardirq.h>
22 #include <linux/scatterlist.h>
23 #include <linux/blk-mq.h>
24 #include <linux/blk-integrity.h>
25 #include <linux/ratelimit.h>
26 #include <asm/unaligned.h>
27 
28 #include <scsi/scsi.h>
29 #include <scsi/scsi_cmnd.h>
30 #include <scsi/scsi_dbg.h>
31 #include <scsi/scsi_device.h>
32 #include <scsi/scsi_driver.h>
33 #include <scsi/scsi_eh.h>
34 #include <scsi/scsi_host.h>
35 #include <scsi/scsi_transport.h> /* __scsi_init_queue() */
36 #include <scsi/scsi_dh.h>
37 
38 #include <trace/events/scsi.h>
39 
40 #include "scsi_debugfs.h"
41 #include "scsi_priv.h"
42 #include "scsi_logging.h"
43 
44 /*
45  * Size of integrity metadata is usually small, 1 inline sg should
46  * cover normal cases.
47  */
48 #ifdef CONFIG_ARCH_NO_SG_CHAIN
49 #define  SCSI_INLINE_PROT_SG_CNT  0
50 #define  SCSI_INLINE_SG_CNT  0
51 #else
52 #define  SCSI_INLINE_PROT_SG_CNT  1
53 #define  SCSI_INLINE_SG_CNT  2
54 #endif
55 
56 static struct kmem_cache *scsi_sense_cache;
57 static DEFINE_MUTEX(scsi_sense_cache_mutex);
58 
59 static void scsi_mq_uninit_cmd(struct scsi_cmnd *cmd);
60 
scsi_init_sense_cache(struct Scsi_Host * shost)61 int scsi_init_sense_cache(struct Scsi_Host *shost)
62 {
63 	int ret = 0;
64 
65 	mutex_lock(&scsi_sense_cache_mutex);
66 	if (!scsi_sense_cache) {
67 		scsi_sense_cache =
68 			kmem_cache_create_usercopy("scsi_sense_cache",
69 				SCSI_SENSE_BUFFERSIZE, 0, SLAB_HWCACHE_ALIGN,
70 				0, SCSI_SENSE_BUFFERSIZE, NULL);
71 		if (!scsi_sense_cache)
72 			ret = -ENOMEM;
73 	}
74 	mutex_unlock(&scsi_sense_cache_mutex);
75 	return ret;
76 }
77 
78 static void
scsi_set_blocked(struct scsi_cmnd * cmd,int reason)79 scsi_set_blocked(struct scsi_cmnd *cmd, int reason)
80 {
81 	struct Scsi_Host *host = cmd->device->host;
82 	struct scsi_device *device = cmd->device;
83 	struct scsi_target *starget = scsi_target(device);
84 
85 	/*
86 	 * Set the appropriate busy bit for the device/host.
87 	 *
88 	 * If the host/device isn't busy, assume that something actually
89 	 * completed, and that we should be able to queue a command now.
90 	 *
91 	 * Note that the prior mid-layer assumption that any host could
92 	 * always queue at least one command is now broken.  The mid-layer
93 	 * will implement a user specifiable stall (see
94 	 * scsi_host.max_host_blocked and scsi_device.max_device_blocked)
95 	 * if a command is requeued with no other commands outstanding
96 	 * either for the device or for the host.
97 	 */
98 	switch (reason) {
99 	case SCSI_MLQUEUE_HOST_BUSY:
100 		atomic_set(&host->host_blocked, host->max_host_blocked);
101 		break;
102 	case SCSI_MLQUEUE_DEVICE_BUSY:
103 	case SCSI_MLQUEUE_EH_RETRY:
104 		atomic_set(&device->device_blocked,
105 			   device->max_device_blocked);
106 		break;
107 	case SCSI_MLQUEUE_TARGET_BUSY:
108 		atomic_set(&starget->target_blocked,
109 			   starget->max_target_blocked);
110 		break;
111 	}
112 }
113 
scsi_mq_requeue_cmd(struct scsi_cmnd * cmd,unsigned long msecs)114 static void scsi_mq_requeue_cmd(struct scsi_cmnd *cmd, unsigned long msecs)
115 {
116 	struct request *rq = scsi_cmd_to_rq(cmd);
117 
118 	if (rq->rq_flags & RQF_DONTPREP) {
119 		rq->rq_flags &= ~RQF_DONTPREP;
120 		scsi_mq_uninit_cmd(cmd);
121 	} else {
122 		WARN_ON_ONCE(true);
123 	}
124 
125 	blk_mq_requeue_request(rq, false);
126 	if (!scsi_host_in_recovery(cmd->device->host))
127 		blk_mq_delay_kick_requeue_list(rq->q, msecs);
128 }
129 
130 /**
131  * __scsi_queue_insert - private queue insertion
132  * @cmd: The SCSI command being requeued
133  * @reason:  The reason for the requeue
134  * @unbusy: Whether the queue should be unbusied
135  *
136  * This is a private queue insertion.  The public interface
137  * scsi_queue_insert() always assumes the queue should be unbusied
138  * because it's always called before the completion.  This function is
139  * for a requeue after completion, which should only occur in this
140  * file.
141  */
__scsi_queue_insert(struct scsi_cmnd * cmd,int reason,bool unbusy)142 static void __scsi_queue_insert(struct scsi_cmnd *cmd, int reason, bool unbusy)
143 {
144 	struct scsi_device *device = cmd->device;
145 
146 	SCSI_LOG_MLQUEUE(1, scmd_printk(KERN_INFO, cmd,
147 		"Inserting command %p into mlqueue\n", cmd));
148 
149 	scsi_set_blocked(cmd, reason);
150 
151 	/*
152 	 * Decrement the counters, since these commands are no longer
153 	 * active on the host/device.
154 	 */
155 	if (unbusy)
156 		scsi_device_unbusy(device, cmd);
157 
158 	/*
159 	 * Requeue this command.  It will go before all other commands
160 	 * that are already in the queue. Schedule requeue work under
161 	 * lock such that the kblockd_schedule_work() call happens
162 	 * before blk_mq_destroy_queue() finishes.
163 	 */
164 	cmd->result = 0;
165 
166 	blk_mq_requeue_request(scsi_cmd_to_rq(cmd),
167 			       !scsi_host_in_recovery(cmd->device->host));
168 }
169 
170 /**
171  * scsi_queue_insert - Reinsert a command in the queue.
172  * @cmd:    command that we are adding to queue.
173  * @reason: why we are inserting command to queue.
174  *
175  * We do this for one of two cases. Either the host is busy and it cannot accept
176  * any more commands for the time being, or the device returned QUEUE_FULL and
177  * can accept no more commands.
178  *
179  * Context: This could be called either from an interrupt context or a normal
180  * process context.
181  */
scsi_queue_insert(struct scsi_cmnd * cmd,int reason)182 void scsi_queue_insert(struct scsi_cmnd *cmd, int reason)
183 {
184 	__scsi_queue_insert(cmd, reason, true);
185 }
186 
187 /**
188  * scsi_execute_cmd - insert request and wait for the result
189  * @sdev:	scsi_device
190  * @cmd:	scsi command
191  * @opf:	block layer request cmd_flags
192  * @buffer:	data buffer
193  * @bufflen:	len of buffer
194  * @timeout:	request timeout in HZ
195  * @retries:	number of times to retry request
196  * @args:	Optional args. See struct definition for field descriptions
197  *
198  * Returns the scsi_cmnd result field if a command was executed, or a negative
199  * Linux error code if we didn't get that far.
200  */
scsi_execute_cmd(struct scsi_device * sdev,const unsigned char * cmd,blk_opf_t opf,void * buffer,unsigned int bufflen,int timeout,int retries,const struct scsi_exec_args * args)201 int scsi_execute_cmd(struct scsi_device *sdev, const unsigned char *cmd,
202 		     blk_opf_t opf, void *buffer, unsigned int bufflen,
203 		     int timeout, int retries,
204 		     const struct scsi_exec_args *args)
205 {
206 	static const struct scsi_exec_args default_args;
207 	struct request *req;
208 	struct scsi_cmnd *scmd;
209 	int ret;
210 
211 	if (!args)
212 		args = &default_args;
213 	else if (WARN_ON_ONCE(args->sense &&
214 			      args->sense_len != SCSI_SENSE_BUFFERSIZE))
215 		return -EINVAL;
216 
217 	req = scsi_alloc_request(sdev->request_queue, opf, args->req_flags);
218 	if (IS_ERR(req))
219 		return PTR_ERR(req);
220 
221 	if (bufflen) {
222 		ret = blk_rq_map_kern(sdev->request_queue, req,
223 				      buffer, bufflen, GFP_NOIO);
224 		if (ret)
225 			goto out;
226 	}
227 	scmd = blk_mq_rq_to_pdu(req);
228 	scmd->cmd_len = COMMAND_SIZE(cmd[0]);
229 	memcpy(scmd->cmnd, cmd, scmd->cmd_len);
230 	scmd->allowed = retries;
231 	scmd->flags |= args->scmd_flags;
232 	req->timeout = timeout;
233 	req->rq_flags |= RQF_QUIET;
234 
235 	/*
236 	 * head injection *required* here otherwise quiesce won't work
237 	 */
238 	blk_execute_rq(req, true);
239 
240 	/*
241 	 * Some devices (USB mass-storage in particular) may transfer
242 	 * garbage data together with a residue indicating that the data
243 	 * is invalid.  Prevent the garbage from being misinterpreted
244 	 * and prevent security leaks by zeroing out the excess data.
245 	 */
246 	if (unlikely(scmd->resid_len > 0 && scmd->resid_len <= bufflen))
247 		memset(buffer + bufflen - scmd->resid_len, 0, scmd->resid_len);
248 
249 	if (args->resid)
250 		*args->resid = scmd->resid_len;
251 	if (args->sense)
252 		memcpy(args->sense, scmd->sense_buffer, SCSI_SENSE_BUFFERSIZE);
253 	if (args->sshdr)
254 		scsi_normalize_sense(scmd->sense_buffer, scmd->sense_len,
255 				     args->sshdr);
256 
257 	ret = scmd->result;
258  out:
259 	blk_mq_free_request(req);
260 
261 	return ret;
262 }
263 EXPORT_SYMBOL(scsi_execute_cmd);
264 
265 /*
266  * Wake up the error handler if necessary. Avoid as follows that the error
267  * handler is not woken up if host in-flight requests number ==
268  * shost->host_failed: use call_rcu() in scsi_eh_scmd_add() in combination
269  * with an RCU read lock in this function to ensure that this function in
270  * its entirety either finishes before scsi_eh_scmd_add() increases the
271  * host_failed counter or that it notices the shost state change made by
272  * scsi_eh_scmd_add().
273  */
scsi_dec_host_busy(struct Scsi_Host * shost,struct scsi_cmnd * cmd)274 static void scsi_dec_host_busy(struct Scsi_Host *shost, struct scsi_cmnd *cmd)
275 {
276 	unsigned long flags;
277 
278 	rcu_read_lock();
279 	__clear_bit(SCMD_STATE_INFLIGHT, &cmd->state);
280 	if (unlikely(scsi_host_in_recovery(shost))) {
281 		unsigned int busy = scsi_host_busy(shost);
282 
283 		spin_lock_irqsave(shost->host_lock, flags);
284 		if (shost->host_failed || shost->host_eh_scheduled)
285 			scsi_eh_wakeup(shost, busy);
286 		spin_unlock_irqrestore(shost->host_lock, flags);
287 	}
288 	rcu_read_unlock();
289 }
290 
scsi_device_unbusy(struct scsi_device * sdev,struct scsi_cmnd * cmd)291 void scsi_device_unbusy(struct scsi_device *sdev, struct scsi_cmnd *cmd)
292 {
293 	struct Scsi_Host *shost = sdev->host;
294 	struct scsi_target *starget = scsi_target(sdev);
295 
296 	scsi_dec_host_busy(shost, cmd);
297 
298 	if (starget->can_queue > 0)
299 		atomic_dec(&starget->target_busy);
300 
301 	sbitmap_put(&sdev->budget_map, cmd->budget_token);
302 	cmd->budget_token = -1;
303 }
304 
305 /*
306  * Kick the queue of SCSI device @sdev if @sdev != current_sdev. Called with
307  * interrupts disabled.
308  */
scsi_kick_sdev_queue(struct scsi_device * sdev,void * data)309 static void scsi_kick_sdev_queue(struct scsi_device *sdev, void *data)
310 {
311 	struct scsi_device *current_sdev = data;
312 
313 	if (sdev != current_sdev)
314 		blk_mq_run_hw_queues(sdev->request_queue, true);
315 }
316 
317 /*
318  * Called for single_lun devices on IO completion. Clear starget_sdev_user,
319  * and call blk_run_queue for all the scsi_devices on the target -
320  * including current_sdev first.
321  *
322  * Called with *no* scsi locks held.
323  */
scsi_single_lun_run(struct scsi_device * current_sdev)324 static void scsi_single_lun_run(struct scsi_device *current_sdev)
325 {
326 	struct Scsi_Host *shost = current_sdev->host;
327 	struct scsi_target *starget = scsi_target(current_sdev);
328 	unsigned long flags;
329 
330 	spin_lock_irqsave(shost->host_lock, flags);
331 	starget->starget_sdev_user = NULL;
332 	spin_unlock_irqrestore(shost->host_lock, flags);
333 
334 	/*
335 	 * Call blk_run_queue for all LUNs on the target, starting with
336 	 * current_sdev. We race with others (to set starget_sdev_user),
337 	 * but in most cases, we will be first. Ideally, each LU on the
338 	 * target would get some limited time or requests on the target.
339 	 */
340 	blk_mq_run_hw_queues(current_sdev->request_queue,
341 			     shost->queuecommand_may_block);
342 
343 	spin_lock_irqsave(shost->host_lock, flags);
344 	if (!starget->starget_sdev_user)
345 		__starget_for_each_device(starget, current_sdev,
346 					  scsi_kick_sdev_queue);
347 	spin_unlock_irqrestore(shost->host_lock, flags);
348 }
349 
scsi_device_is_busy(struct scsi_device * sdev)350 static inline bool scsi_device_is_busy(struct scsi_device *sdev)
351 {
352 	if (scsi_device_busy(sdev) >= sdev->queue_depth)
353 		return true;
354 	if (atomic_read(&sdev->device_blocked) > 0)
355 		return true;
356 	return false;
357 }
358 
scsi_target_is_busy(struct scsi_target * starget)359 static inline bool scsi_target_is_busy(struct scsi_target *starget)
360 {
361 	if (starget->can_queue > 0) {
362 		if (atomic_read(&starget->target_busy) >= starget->can_queue)
363 			return true;
364 		if (atomic_read(&starget->target_blocked) > 0)
365 			return true;
366 	}
367 	return false;
368 }
369 
scsi_host_is_busy(struct Scsi_Host * shost)370 static inline bool scsi_host_is_busy(struct Scsi_Host *shost)
371 {
372 	if (atomic_read(&shost->host_blocked) > 0)
373 		return true;
374 	if (shost->host_self_blocked)
375 		return true;
376 	return false;
377 }
378 
scsi_starved_list_run(struct Scsi_Host * shost)379 static void scsi_starved_list_run(struct Scsi_Host *shost)
380 {
381 	LIST_HEAD(starved_list);
382 	struct scsi_device *sdev;
383 	unsigned long flags;
384 
385 	spin_lock_irqsave(shost->host_lock, flags);
386 	list_splice_init(&shost->starved_list, &starved_list);
387 
388 	while (!list_empty(&starved_list)) {
389 		struct request_queue *slq;
390 
391 		/*
392 		 * As long as shost is accepting commands and we have
393 		 * starved queues, call blk_run_queue. scsi_request_fn
394 		 * drops the queue_lock and can add us back to the
395 		 * starved_list.
396 		 *
397 		 * host_lock protects the starved_list and starved_entry.
398 		 * scsi_request_fn must get the host_lock before checking
399 		 * or modifying starved_list or starved_entry.
400 		 */
401 		if (scsi_host_is_busy(shost))
402 			break;
403 
404 		sdev = list_entry(starved_list.next,
405 				  struct scsi_device, starved_entry);
406 		list_del_init(&sdev->starved_entry);
407 		if (scsi_target_is_busy(scsi_target(sdev))) {
408 			list_move_tail(&sdev->starved_entry,
409 				       &shost->starved_list);
410 			continue;
411 		}
412 
413 		/*
414 		 * Once we drop the host lock, a racing scsi_remove_device()
415 		 * call may remove the sdev from the starved list and destroy
416 		 * it and the queue.  Mitigate by taking a reference to the
417 		 * queue and never touching the sdev again after we drop the
418 		 * host lock.  Note: if __scsi_remove_device() invokes
419 		 * blk_mq_destroy_queue() before the queue is run from this
420 		 * function then blk_run_queue() will return immediately since
421 		 * blk_mq_destroy_queue() marks the queue with QUEUE_FLAG_DYING.
422 		 */
423 		slq = sdev->request_queue;
424 		if (!blk_get_queue(slq))
425 			continue;
426 		spin_unlock_irqrestore(shost->host_lock, flags);
427 
428 		blk_mq_run_hw_queues(slq, false);
429 		blk_put_queue(slq);
430 
431 		spin_lock_irqsave(shost->host_lock, flags);
432 	}
433 	/* put any unprocessed entries back */
434 	list_splice(&starved_list, &shost->starved_list);
435 	spin_unlock_irqrestore(shost->host_lock, flags);
436 }
437 
438 /**
439  * scsi_run_queue - Select a proper request queue to serve next.
440  * @q:  last request's queue
441  *
442  * The previous command was completely finished, start a new one if possible.
443  */
scsi_run_queue(struct request_queue * q)444 static void scsi_run_queue(struct request_queue *q)
445 {
446 	struct scsi_device *sdev = q->queuedata;
447 
448 	if (scsi_target(sdev)->single_lun)
449 		scsi_single_lun_run(sdev);
450 	if (!list_empty(&sdev->host->starved_list))
451 		scsi_starved_list_run(sdev->host);
452 
453 	/* Note: blk_mq_kick_requeue_list() runs the queue asynchronously. */
454 	blk_mq_kick_requeue_list(q);
455 }
456 
scsi_requeue_run_queue(struct work_struct * work)457 void scsi_requeue_run_queue(struct work_struct *work)
458 {
459 	struct scsi_device *sdev;
460 	struct request_queue *q;
461 
462 	sdev = container_of(work, struct scsi_device, requeue_work);
463 	q = sdev->request_queue;
464 	scsi_run_queue(q);
465 }
466 
scsi_run_host_queues(struct Scsi_Host * shost)467 void scsi_run_host_queues(struct Scsi_Host *shost)
468 {
469 	struct scsi_device *sdev;
470 
471 	shost_for_each_device(sdev, shost)
472 		scsi_run_queue(sdev->request_queue);
473 }
474 
scsi_uninit_cmd(struct scsi_cmnd * cmd)475 static void scsi_uninit_cmd(struct scsi_cmnd *cmd)
476 {
477 	if (!blk_rq_is_passthrough(scsi_cmd_to_rq(cmd))) {
478 		struct scsi_driver *drv = scsi_cmd_to_driver(cmd);
479 
480 		if (drv->uninit_command)
481 			drv->uninit_command(cmd);
482 	}
483 }
484 
scsi_free_sgtables(struct scsi_cmnd * cmd)485 void scsi_free_sgtables(struct scsi_cmnd *cmd)
486 {
487 	if (cmd->sdb.table.nents)
488 		sg_free_table_chained(&cmd->sdb.table,
489 				SCSI_INLINE_SG_CNT);
490 	if (scsi_prot_sg_count(cmd))
491 		sg_free_table_chained(&cmd->prot_sdb->table,
492 				SCSI_INLINE_PROT_SG_CNT);
493 }
494 EXPORT_SYMBOL_GPL(scsi_free_sgtables);
495 
scsi_mq_uninit_cmd(struct scsi_cmnd * cmd)496 static void scsi_mq_uninit_cmd(struct scsi_cmnd *cmd)
497 {
498 	scsi_free_sgtables(cmd);
499 	scsi_uninit_cmd(cmd);
500 }
501 
scsi_run_queue_async(struct scsi_device * sdev)502 static void scsi_run_queue_async(struct scsi_device *sdev)
503 {
504 	if (scsi_host_in_recovery(sdev->host))
505 		return;
506 
507 	if (scsi_target(sdev)->single_lun ||
508 	    !list_empty(&sdev->host->starved_list)) {
509 		kblockd_schedule_work(&sdev->requeue_work);
510 	} else {
511 		/*
512 		 * smp_mb() present in sbitmap_queue_clear() or implied in
513 		 * .end_io is for ordering writing .device_busy in
514 		 * scsi_device_unbusy() and reading sdev->restarts.
515 		 */
516 		int old = atomic_read(&sdev->restarts);
517 
518 		/*
519 		 * ->restarts has to be kept as non-zero if new budget
520 		 *  contention occurs.
521 		 *
522 		 *  No need to run queue when either another re-run
523 		 *  queue wins in updating ->restarts or a new budget
524 		 *  contention occurs.
525 		 */
526 		if (old && atomic_cmpxchg(&sdev->restarts, old, 0) == old)
527 			blk_mq_run_hw_queues(sdev->request_queue, true);
528 	}
529 }
530 
531 /* Returns false when no more bytes to process, true if there are more */
scsi_end_request(struct request * req,blk_status_t error,unsigned int bytes)532 static bool scsi_end_request(struct request *req, blk_status_t error,
533 		unsigned int bytes)
534 {
535 	struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req);
536 	struct scsi_device *sdev = cmd->device;
537 	struct request_queue *q = sdev->request_queue;
538 
539 	if (blk_update_request(req, error, bytes))
540 		return true;
541 
542 	// XXX:
543 	if (blk_queue_add_random(q))
544 		add_disk_randomness(req->q->disk);
545 
546 	WARN_ON_ONCE(!blk_rq_is_passthrough(req) &&
547 		     !(cmd->flags & SCMD_INITIALIZED));
548 	cmd->flags = 0;
549 
550 	/*
551 	 * Calling rcu_barrier() is not necessary here because the
552 	 * SCSI error handler guarantees that the function called by
553 	 * call_rcu() has been called before scsi_end_request() is
554 	 * called.
555 	 */
556 	destroy_rcu_head(&cmd->rcu);
557 
558 	/*
559 	 * In the MQ case the command gets freed by __blk_mq_end_request,
560 	 * so we have to do all cleanup that depends on it earlier.
561 	 *
562 	 * We also can't kick the queues from irq context, so we
563 	 * will have to defer it to a workqueue.
564 	 */
565 	scsi_mq_uninit_cmd(cmd);
566 
567 	/*
568 	 * queue is still alive, so grab the ref for preventing it
569 	 * from being cleaned up during running queue.
570 	 */
571 	percpu_ref_get(&q->q_usage_counter);
572 
573 	__blk_mq_end_request(req, error);
574 
575 	scsi_run_queue_async(sdev);
576 
577 	percpu_ref_put(&q->q_usage_counter);
578 	return false;
579 }
580 
581 /**
582  * scsi_result_to_blk_status - translate a SCSI result code into blk_status_t
583  * @result:	scsi error code
584  *
585  * Translate a SCSI result code into a blk_status_t value.
586  */
scsi_result_to_blk_status(int result)587 static blk_status_t scsi_result_to_blk_status(int result)
588 {
589 	/*
590 	 * Check the scsi-ml byte first in case we converted a host or status
591 	 * byte.
592 	 */
593 	switch (scsi_ml_byte(result)) {
594 	case SCSIML_STAT_OK:
595 		break;
596 	case SCSIML_STAT_RESV_CONFLICT:
597 		return BLK_STS_RESV_CONFLICT;
598 	case SCSIML_STAT_NOSPC:
599 		return BLK_STS_NOSPC;
600 	case SCSIML_STAT_MED_ERROR:
601 		return BLK_STS_MEDIUM;
602 	case SCSIML_STAT_TGT_FAILURE:
603 		return BLK_STS_TARGET;
604 	case SCSIML_STAT_DL_TIMEOUT:
605 		return BLK_STS_DURATION_LIMIT;
606 	}
607 
608 	switch (host_byte(result)) {
609 	case DID_OK:
610 		if (scsi_status_is_good(result))
611 			return BLK_STS_OK;
612 		return BLK_STS_IOERR;
613 	case DID_TRANSPORT_FAILFAST:
614 	case DID_TRANSPORT_MARGINAL:
615 		return BLK_STS_TRANSPORT;
616 	default:
617 		return BLK_STS_IOERR;
618 	}
619 }
620 
621 /**
622  * scsi_rq_err_bytes - determine number of bytes till the next failure boundary
623  * @rq: request to examine
624  *
625  * Description:
626  *     A request could be merge of IOs which require different failure
627  *     handling.  This function determines the number of bytes which
628  *     can be failed from the beginning of the request without
629  *     crossing into area which need to be retried further.
630  *
631  * Return:
632  *     The number of bytes to fail.
633  */
scsi_rq_err_bytes(const struct request * rq)634 static unsigned int scsi_rq_err_bytes(const struct request *rq)
635 {
636 	blk_opf_t ff = rq->cmd_flags & REQ_FAILFAST_MASK;
637 	unsigned int bytes = 0;
638 	struct bio *bio;
639 
640 	if (!(rq->rq_flags & RQF_MIXED_MERGE))
641 		return blk_rq_bytes(rq);
642 
643 	/*
644 	 * Currently the only 'mixing' which can happen is between
645 	 * different fastfail types.  We can safely fail portions
646 	 * which have all the failfast bits that the first one has -
647 	 * the ones which are at least as eager to fail as the first
648 	 * one.
649 	 */
650 	for (bio = rq->bio; bio; bio = bio->bi_next) {
651 		if ((bio->bi_opf & ff) != ff)
652 			break;
653 		bytes += bio->bi_iter.bi_size;
654 	}
655 
656 	/* this could lead to infinite loop */
657 	BUG_ON(blk_rq_bytes(rq) && !bytes);
658 	return bytes;
659 }
660 
scsi_cmd_runtime_exceeced(struct scsi_cmnd * cmd)661 static bool scsi_cmd_runtime_exceeced(struct scsi_cmnd *cmd)
662 {
663 	struct request *req = scsi_cmd_to_rq(cmd);
664 	unsigned long wait_for;
665 
666 	if (cmd->allowed == SCSI_CMD_RETRIES_NO_LIMIT)
667 		return false;
668 
669 	wait_for = (cmd->allowed + 1) * req->timeout;
670 	if (time_before(cmd->jiffies_at_alloc + wait_for, jiffies)) {
671 		scmd_printk(KERN_ERR, cmd, "timing out command, waited %lus\n",
672 			    wait_for/HZ);
673 		return true;
674 	}
675 	return false;
676 }
677 
678 /*
679  * When ALUA transition state is returned, reprep the cmd to
680  * use the ALUA handler's transition timeout. Delay the reprep
681  * 1 sec to avoid aggressive retries of the target in that
682  * state.
683  */
684 #define ALUA_TRANSITION_REPREP_DELAY	1000
685 
686 /* Helper for scsi_io_completion() when special action required. */
scsi_io_completion_action(struct scsi_cmnd * cmd,int result)687 static void scsi_io_completion_action(struct scsi_cmnd *cmd, int result)
688 {
689 	struct request *req = scsi_cmd_to_rq(cmd);
690 	int level = 0;
691 	enum {ACTION_FAIL, ACTION_REPREP, ACTION_DELAYED_REPREP,
692 	      ACTION_RETRY, ACTION_DELAYED_RETRY} action;
693 	struct scsi_sense_hdr sshdr;
694 	bool sense_valid;
695 	bool sense_current = true;      /* false implies "deferred sense" */
696 	blk_status_t blk_stat;
697 
698 	sense_valid = scsi_command_normalize_sense(cmd, &sshdr);
699 	if (sense_valid)
700 		sense_current = !scsi_sense_is_deferred(&sshdr);
701 
702 	blk_stat = scsi_result_to_blk_status(result);
703 
704 	if (host_byte(result) == DID_RESET) {
705 		/* Third party bus reset or reset for error recovery
706 		 * reasons.  Just retry the command and see what
707 		 * happens.
708 		 */
709 		action = ACTION_RETRY;
710 	} else if (sense_valid && sense_current) {
711 		switch (sshdr.sense_key) {
712 		case UNIT_ATTENTION:
713 			if (cmd->device->removable) {
714 				/* Detected disc change.  Set a bit
715 				 * and quietly refuse further access.
716 				 */
717 				cmd->device->changed = 1;
718 				action = ACTION_FAIL;
719 			} else {
720 				/* Must have been a power glitch, or a
721 				 * bus reset.  Could not have been a
722 				 * media change, so we just retry the
723 				 * command and see what happens.
724 				 */
725 				action = ACTION_RETRY;
726 			}
727 			break;
728 		case ILLEGAL_REQUEST:
729 			/* If we had an ILLEGAL REQUEST returned, then
730 			 * we may have performed an unsupported
731 			 * command.  The only thing this should be
732 			 * would be a ten byte read where only a six
733 			 * byte read was supported.  Also, on a system
734 			 * where READ CAPACITY failed, we may have
735 			 * read past the end of the disk.
736 			 */
737 			if ((cmd->device->use_10_for_rw &&
738 			    sshdr.asc == 0x20 && sshdr.ascq == 0x00) &&
739 			    (cmd->cmnd[0] == READ_10 ||
740 			     cmd->cmnd[0] == WRITE_10)) {
741 				/* This will issue a new 6-byte command. */
742 				cmd->device->use_10_for_rw = 0;
743 				action = ACTION_REPREP;
744 			} else if (sshdr.asc == 0x10) /* DIX */ {
745 				action = ACTION_FAIL;
746 				blk_stat = BLK_STS_PROTECTION;
747 			/* INVALID COMMAND OPCODE or INVALID FIELD IN CDB */
748 			} else if (sshdr.asc == 0x20 || sshdr.asc == 0x24) {
749 				action = ACTION_FAIL;
750 				blk_stat = BLK_STS_TARGET;
751 			} else
752 				action = ACTION_FAIL;
753 			break;
754 		case ABORTED_COMMAND:
755 			action = ACTION_FAIL;
756 			if (sshdr.asc == 0x10) /* DIF */
757 				blk_stat = BLK_STS_PROTECTION;
758 			break;
759 		case NOT_READY:
760 			/* If the device is in the process of becoming
761 			 * ready, or has a temporary blockage, retry.
762 			 */
763 			if (sshdr.asc == 0x04) {
764 				switch (sshdr.ascq) {
765 				case 0x01: /* becoming ready */
766 				case 0x04: /* format in progress */
767 				case 0x05: /* rebuild in progress */
768 				case 0x06: /* recalculation in progress */
769 				case 0x07: /* operation in progress */
770 				case 0x08: /* Long write in progress */
771 				case 0x09: /* self test in progress */
772 				case 0x11: /* notify (enable spinup) required */
773 				case 0x14: /* space allocation in progress */
774 				case 0x1a: /* start stop unit in progress */
775 				case 0x1b: /* sanitize in progress */
776 				case 0x1d: /* configuration in progress */
777 				case 0x24: /* depopulation in progress */
778 					action = ACTION_DELAYED_RETRY;
779 					break;
780 				case 0x0a: /* ALUA state transition */
781 					action = ACTION_DELAYED_REPREP;
782 					break;
783 				default:
784 					action = ACTION_FAIL;
785 					break;
786 				}
787 			} else
788 				action = ACTION_FAIL;
789 			break;
790 		case VOLUME_OVERFLOW:
791 			/* See SSC3rXX or current. */
792 			action = ACTION_FAIL;
793 			break;
794 		case DATA_PROTECT:
795 			action = ACTION_FAIL;
796 			if ((sshdr.asc == 0x0C && sshdr.ascq == 0x12) ||
797 			    (sshdr.asc == 0x55 &&
798 			     (sshdr.ascq == 0x0E || sshdr.ascq == 0x0F))) {
799 				/* Insufficient zone resources */
800 				blk_stat = BLK_STS_ZONE_OPEN_RESOURCE;
801 			}
802 			break;
803 		case COMPLETED:
804 			fallthrough;
805 		default:
806 			action = ACTION_FAIL;
807 			break;
808 		}
809 	} else
810 		action = ACTION_FAIL;
811 
812 	if (action != ACTION_FAIL && scsi_cmd_runtime_exceeced(cmd))
813 		action = ACTION_FAIL;
814 
815 	switch (action) {
816 	case ACTION_FAIL:
817 		/* Give up and fail the remainder of the request */
818 		if (!(req->rq_flags & RQF_QUIET)) {
819 			static DEFINE_RATELIMIT_STATE(_rs,
820 					DEFAULT_RATELIMIT_INTERVAL,
821 					DEFAULT_RATELIMIT_BURST);
822 
823 			if (unlikely(scsi_logging_level))
824 				level =
825 				     SCSI_LOG_LEVEL(SCSI_LOG_MLCOMPLETE_SHIFT,
826 						    SCSI_LOG_MLCOMPLETE_BITS);
827 
828 			/*
829 			 * if logging is enabled the failure will be printed
830 			 * in scsi_log_completion(), so avoid duplicate messages
831 			 */
832 			if (!level && __ratelimit(&_rs)) {
833 				scsi_print_result(cmd, NULL, FAILED);
834 				if (sense_valid)
835 					scsi_print_sense(cmd);
836 				scsi_print_command(cmd);
837 			}
838 		}
839 		if (!scsi_end_request(req, blk_stat, scsi_rq_err_bytes(req)))
840 			return;
841 		fallthrough;
842 	case ACTION_REPREP:
843 		scsi_mq_requeue_cmd(cmd, 0);
844 		break;
845 	case ACTION_DELAYED_REPREP:
846 		scsi_mq_requeue_cmd(cmd, ALUA_TRANSITION_REPREP_DELAY);
847 		break;
848 	case ACTION_RETRY:
849 		/* Retry the same command immediately */
850 		__scsi_queue_insert(cmd, SCSI_MLQUEUE_EH_RETRY, false);
851 		break;
852 	case ACTION_DELAYED_RETRY:
853 		/* Retry the same command after a delay */
854 		__scsi_queue_insert(cmd, SCSI_MLQUEUE_DEVICE_BUSY, false);
855 		break;
856 	}
857 }
858 
859 /*
860  * Helper for scsi_io_completion() when cmd->result is non-zero. Returns a
861  * new result that may suppress further error checking. Also modifies
862  * *blk_statp in some cases.
863  */
scsi_io_completion_nz_result(struct scsi_cmnd * cmd,int result,blk_status_t * blk_statp)864 static int scsi_io_completion_nz_result(struct scsi_cmnd *cmd, int result,
865 					blk_status_t *blk_statp)
866 {
867 	bool sense_valid;
868 	bool sense_current = true;	/* false implies "deferred sense" */
869 	struct request *req = scsi_cmd_to_rq(cmd);
870 	struct scsi_sense_hdr sshdr;
871 
872 	sense_valid = scsi_command_normalize_sense(cmd, &sshdr);
873 	if (sense_valid)
874 		sense_current = !scsi_sense_is_deferred(&sshdr);
875 
876 	if (blk_rq_is_passthrough(req)) {
877 		if (sense_valid) {
878 			/*
879 			 * SG_IO wants current and deferred errors
880 			 */
881 			cmd->sense_len = min(8 + cmd->sense_buffer[7],
882 					     SCSI_SENSE_BUFFERSIZE);
883 		}
884 		if (sense_current)
885 			*blk_statp = scsi_result_to_blk_status(result);
886 	} else if (blk_rq_bytes(req) == 0 && sense_current) {
887 		/*
888 		 * Flush commands do not transfers any data, and thus cannot use
889 		 * good_bytes != blk_rq_bytes(req) as the signal for an error.
890 		 * This sets *blk_statp explicitly for the problem case.
891 		 */
892 		*blk_statp = scsi_result_to_blk_status(result);
893 	}
894 	/*
895 	 * Recovered errors need reporting, but they're always treated as
896 	 * success, so fiddle the result code here.  For passthrough requests
897 	 * we already took a copy of the original into sreq->result which
898 	 * is what gets returned to the user
899 	 */
900 	if (sense_valid && (sshdr.sense_key == RECOVERED_ERROR)) {
901 		bool do_print = true;
902 		/*
903 		 * if ATA PASS-THROUGH INFORMATION AVAILABLE [0x0, 0x1d]
904 		 * skip print since caller wants ATA registers. Only occurs
905 		 * on SCSI ATA PASS_THROUGH commands when CK_COND=1
906 		 */
907 		if ((sshdr.asc == 0x0) && (sshdr.ascq == 0x1d))
908 			do_print = false;
909 		else if (req->rq_flags & RQF_QUIET)
910 			do_print = false;
911 		if (do_print)
912 			scsi_print_sense(cmd);
913 		result = 0;
914 		/* for passthrough, *blk_statp may be set */
915 		*blk_statp = BLK_STS_OK;
916 	}
917 	/*
918 	 * Another corner case: the SCSI status byte is non-zero but 'good'.
919 	 * Example: PRE-FETCH command returns SAM_STAT_CONDITION_MET when
920 	 * it is able to fit nominated LBs in its cache (and SAM_STAT_GOOD
921 	 * if it can't fit). Treat SAM_STAT_CONDITION_MET and the related
922 	 * intermediate statuses (both obsolete in SAM-4) as good.
923 	 */
924 	if ((result & 0xff) && scsi_status_is_good(result)) {
925 		result = 0;
926 		*blk_statp = BLK_STS_OK;
927 	}
928 	return result;
929 }
930 
931 /**
932  * scsi_io_completion - Completion processing for SCSI commands.
933  * @cmd:	command that is finished.
934  * @good_bytes:	number of processed bytes.
935  *
936  * We will finish off the specified number of sectors. If we are done, the
937  * command block will be released and the queue function will be goosed. If we
938  * are not done then we have to figure out what to do next:
939  *
940  *   a) We can call scsi_mq_requeue_cmd().  The request will be
941  *	unprepared and put back on the queue.  Then a new command will
942  *	be created for it.  This should be used if we made forward
943  *	progress, or if we want to switch from READ(10) to READ(6) for
944  *	example.
945  *
946  *   b) We can call scsi_io_completion_action().  The request will be
947  *	put back on the queue and retried using the same command as
948  *	before, possibly after a delay.
949  *
950  *   c) We can call scsi_end_request() with blk_stat other than
951  *	BLK_STS_OK, to fail the remainder of the request.
952  */
scsi_io_completion(struct scsi_cmnd * cmd,unsigned int good_bytes)953 void scsi_io_completion(struct scsi_cmnd *cmd, unsigned int good_bytes)
954 {
955 	int result = cmd->result;
956 	struct request *req = scsi_cmd_to_rq(cmd);
957 	blk_status_t blk_stat = BLK_STS_OK;
958 
959 	if (unlikely(result))	/* a nz result may or may not be an error */
960 		result = scsi_io_completion_nz_result(cmd, result, &blk_stat);
961 
962 	/*
963 	 * Next deal with any sectors which we were able to correctly
964 	 * handle.
965 	 */
966 	SCSI_LOG_HLCOMPLETE(1, scmd_printk(KERN_INFO, cmd,
967 		"%u sectors total, %d bytes done.\n",
968 		blk_rq_sectors(req), good_bytes));
969 
970 	/*
971 	 * Failed, zero length commands always need to drop down
972 	 * to retry code. Fast path should return in this block.
973 	 */
974 	if (likely(blk_rq_bytes(req) > 0 || blk_stat == BLK_STS_OK)) {
975 		if (likely(!scsi_end_request(req, blk_stat, good_bytes)))
976 			return; /* no bytes remaining */
977 	}
978 
979 	/* Kill remainder if no retries. */
980 	if (unlikely(blk_stat && scsi_noretry_cmd(cmd))) {
981 		if (scsi_end_request(req, blk_stat, blk_rq_bytes(req)))
982 			WARN_ONCE(true,
983 			    "Bytes remaining after failed, no-retry command");
984 		return;
985 	}
986 
987 	/*
988 	 * If there had been no error, but we have leftover bytes in the
989 	 * request just queue the command up again.
990 	 */
991 	if (likely(result == 0))
992 		scsi_mq_requeue_cmd(cmd, 0);
993 	else
994 		scsi_io_completion_action(cmd, result);
995 }
996 
scsi_cmd_needs_dma_drain(struct scsi_device * sdev,struct request * rq)997 static inline bool scsi_cmd_needs_dma_drain(struct scsi_device *sdev,
998 		struct request *rq)
999 {
1000 	return sdev->dma_drain_len && blk_rq_is_passthrough(rq) &&
1001 	       !op_is_write(req_op(rq)) &&
1002 	       sdev->host->hostt->dma_need_drain(rq);
1003 }
1004 
1005 /**
1006  * scsi_alloc_sgtables - Allocate and initialize data and integrity scatterlists
1007  * @cmd: SCSI command data structure to initialize.
1008  *
1009  * Initializes @cmd->sdb and also @cmd->prot_sdb if data integrity is enabled
1010  * for @cmd.
1011  *
1012  * Returns:
1013  * * BLK_STS_OK       - on success
1014  * * BLK_STS_RESOURCE - if the failure is retryable
1015  * * BLK_STS_IOERR    - if the failure is fatal
1016  */
scsi_alloc_sgtables(struct scsi_cmnd * cmd)1017 blk_status_t scsi_alloc_sgtables(struct scsi_cmnd *cmd)
1018 {
1019 	struct scsi_device *sdev = cmd->device;
1020 	struct request *rq = scsi_cmd_to_rq(cmd);
1021 	unsigned short nr_segs = blk_rq_nr_phys_segments(rq);
1022 	struct scatterlist *last_sg = NULL;
1023 	blk_status_t ret;
1024 	bool need_drain = scsi_cmd_needs_dma_drain(sdev, rq);
1025 	int count;
1026 
1027 	if (WARN_ON_ONCE(!nr_segs))
1028 		return BLK_STS_IOERR;
1029 
1030 	/*
1031 	 * Make sure there is space for the drain.  The driver must adjust
1032 	 * max_hw_segments to be prepared for this.
1033 	 */
1034 	if (need_drain)
1035 		nr_segs++;
1036 
1037 	/*
1038 	 * If sg table allocation fails, requeue request later.
1039 	 */
1040 	if (unlikely(sg_alloc_table_chained(&cmd->sdb.table, nr_segs,
1041 			cmd->sdb.table.sgl, SCSI_INLINE_SG_CNT)))
1042 		return BLK_STS_RESOURCE;
1043 
1044 	/*
1045 	 * Next, walk the list, and fill in the addresses and sizes of
1046 	 * each segment.
1047 	 */
1048 	count = __blk_rq_map_sg(rq->q, rq, cmd->sdb.table.sgl, &last_sg);
1049 
1050 	if (blk_rq_bytes(rq) & rq->q->dma_pad_mask) {
1051 		unsigned int pad_len =
1052 			(rq->q->dma_pad_mask & ~blk_rq_bytes(rq)) + 1;
1053 
1054 		last_sg->length += pad_len;
1055 		cmd->extra_len += pad_len;
1056 	}
1057 
1058 	if (need_drain) {
1059 		sg_unmark_end(last_sg);
1060 		last_sg = sg_next(last_sg);
1061 		sg_set_buf(last_sg, sdev->dma_drain_buf, sdev->dma_drain_len);
1062 		sg_mark_end(last_sg);
1063 
1064 		cmd->extra_len += sdev->dma_drain_len;
1065 		count++;
1066 	}
1067 
1068 	BUG_ON(count > cmd->sdb.table.nents);
1069 	cmd->sdb.table.nents = count;
1070 	cmd->sdb.length = blk_rq_payload_bytes(rq);
1071 
1072 	if (blk_integrity_rq(rq)) {
1073 		struct scsi_data_buffer *prot_sdb = cmd->prot_sdb;
1074 		int ivecs;
1075 
1076 		if (WARN_ON_ONCE(!prot_sdb)) {
1077 			/*
1078 			 * This can happen if someone (e.g. multipath)
1079 			 * queues a command to a device on an adapter
1080 			 * that does not support DIX.
1081 			 */
1082 			ret = BLK_STS_IOERR;
1083 			goto out_free_sgtables;
1084 		}
1085 
1086 		ivecs = blk_rq_count_integrity_sg(rq->q, rq->bio);
1087 
1088 		if (sg_alloc_table_chained(&prot_sdb->table, ivecs,
1089 				prot_sdb->table.sgl,
1090 				SCSI_INLINE_PROT_SG_CNT)) {
1091 			ret = BLK_STS_RESOURCE;
1092 			goto out_free_sgtables;
1093 		}
1094 
1095 		count = blk_rq_map_integrity_sg(rq->q, rq->bio,
1096 						prot_sdb->table.sgl);
1097 		BUG_ON(count > ivecs);
1098 		BUG_ON(count > queue_max_integrity_segments(rq->q));
1099 
1100 		cmd->prot_sdb = prot_sdb;
1101 		cmd->prot_sdb->table.nents = count;
1102 	}
1103 
1104 	return BLK_STS_OK;
1105 out_free_sgtables:
1106 	scsi_free_sgtables(cmd);
1107 	return ret;
1108 }
1109 EXPORT_SYMBOL(scsi_alloc_sgtables);
1110 
1111 /**
1112  * scsi_initialize_rq - initialize struct scsi_cmnd partially
1113  * @rq: Request associated with the SCSI command to be initialized.
1114  *
1115  * This function initializes the members of struct scsi_cmnd that must be
1116  * initialized before request processing starts and that won't be
1117  * reinitialized if a SCSI command is requeued.
1118  */
scsi_initialize_rq(struct request * rq)1119 static void scsi_initialize_rq(struct request *rq)
1120 {
1121 	struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(rq);
1122 
1123 	memset(cmd->cmnd, 0, sizeof(cmd->cmnd));
1124 	cmd->cmd_len = MAX_COMMAND_SIZE;
1125 	cmd->sense_len = 0;
1126 	init_rcu_head(&cmd->rcu);
1127 	cmd->jiffies_at_alloc = jiffies;
1128 	cmd->retries = 0;
1129 }
1130 
scsi_alloc_request(struct request_queue * q,blk_opf_t opf,blk_mq_req_flags_t flags)1131 struct request *scsi_alloc_request(struct request_queue *q, blk_opf_t opf,
1132 				   blk_mq_req_flags_t flags)
1133 {
1134 	struct request *rq;
1135 
1136 	rq = blk_mq_alloc_request(q, opf, flags);
1137 	if (!IS_ERR(rq))
1138 		scsi_initialize_rq(rq);
1139 	return rq;
1140 }
1141 EXPORT_SYMBOL_GPL(scsi_alloc_request);
1142 
1143 /*
1144  * Only called when the request isn't completed by SCSI, and not freed by
1145  * SCSI
1146  */
scsi_cleanup_rq(struct request * rq)1147 static void scsi_cleanup_rq(struct request *rq)
1148 {
1149 	if (rq->rq_flags & RQF_DONTPREP) {
1150 		scsi_mq_uninit_cmd(blk_mq_rq_to_pdu(rq));
1151 		rq->rq_flags &= ~RQF_DONTPREP;
1152 	}
1153 }
1154 
1155 /* Called before a request is prepared. See also scsi_mq_prep_fn(). */
scsi_init_command(struct scsi_device * dev,struct scsi_cmnd * cmd)1156 void scsi_init_command(struct scsi_device *dev, struct scsi_cmnd *cmd)
1157 {
1158 	struct request *rq = scsi_cmd_to_rq(cmd);
1159 
1160 	if (!blk_rq_is_passthrough(rq) && !(cmd->flags & SCMD_INITIALIZED)) {
1161 		cmd->flags |= SCMD_INITIALIZED;
1162 		scsi_initialize_rq(rq);
1163 	}
1164 
1165 	cmd->device = dev;
1166 	INIT_LIST_HEAD(&cmd->eh_entry);
1167 	INIT_DELAYED_WORK(&cmd->abort_work, scmd_eh_abort_handler);
1168 }
1169 
scsi_setup_scsi_cmnd(struct scsi_device * sdev,struct request * req)1170 static blk_status_t scsi_setup_scsi_cmnd(struct scsi_device *sdev,
1171 		struct request *req)
1172 {
1173 	struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req);
1174 
1175 	/*
1176 	 * Passthrough requests may transfer data, in which case they must
1177 	 * a bio attached to them.  Or they might contain a SCSI command
1178 	 * that does not transfer data, in which case they may optionally
1179 	 * submit a request without an attached bio.
1180 	 */
1181 	if (req->bio) {
1182 		blk_status_t ret = scsi_alloc_sgtables(cmd);
1183 		if (unlikely(ret != BLK_STS_OK))
1184 			return ret;
1185 	} else {
1186 		BUG_ON(blk_rq_bytes(req));
1187 
1188 		memset(&cmd->sdb, 0, sizeof(cmd->sdb));
1189 	}
1190 
1191 	cmd->transfersize = blk_rq_bytes(req);
1192 	return BLK_STS_OK;
1193 }
1194 
1195 static blk_status_t
scsi_device_state_check(struct scsi_device * sdev,struct request * req)1196 scsi_device_state_check(struct scsi_device *sdev, struct request *req)
1197 {
1198 	switch (sdev->sdev_state) {
1199 	case SDEV_CREATED:
1200 		return BLK_STS_OK;
1201 	case SDEV_OFFLINE:
1202 	case SDEV_TRANSPORT_OFFLINE:
1203 		/*
1204 		 * If the device is offline we refuse to process any
1205 		 * commands.  The device must be brought online
1206 		 * before trying any recovery commands.
1207 		 */
1208 		if (!sdev->offline_already) {
1209 			sdev->offline_already = true;
1210 			sdev_printk(KERN_ERR, sdev,
1211 				    "rejecting I/O to offline device\n");
1212 		}
1213 		return BLK_STS_IOERR;
1214 	case SDEV_DEL:
1215 		/*
1216 		 * If the device is fully deleted, we refuse to
1217 		 * process any commands as well.
1218 		 */
1219 		sdev_printk(KERN_ERR, sdev,
1220 			    "rejecting I/O to dead device\n");
1221 		return BLK_STS_IOERR;
1222 	case SDEV_BLOCK:
1223 	case SDEV_CREATED_BLOCK:
1224 		return BLK_STS_RESOURCE;
1225 	case SDEV_QUIESCE:
1226 		/*
1227 		 * If the device is blocked we only accept power management
1228 		 * commands.
1229 		 */
1230 		if (req && WARN_ON_ONCE(!(req->rq_flags & RQF_PM)))
1231 			return BLK_STS_RESOURCE;
1232 		return BLK_STS_OK;
1233 	default:
1234 		/*
1235 		 * For any other not fully online state we only allow
1236 		 * power management commands.
1237 		 */
1238 		if (req && !(req->rq_flags & RQF_PM))
1239 			return BLK_STS_OFFLINE;
1240 		return BLK_STS_OK;
1241 	}
1242 }
1243 
1244 /*
1245  * scsi_dev_queue_ready: if we can send requests to sdev, assign one token
1246  * and return the token else return -1.
1247  */
scsi_dev_queue_ready(struct request_queue * q,struct scsi_device * sdev)1248 static inline int scsi_dev_queue_ready(struct request_queue *q,
1249 				  struct scsi_device *sdev)
1250 {
1251 	int token;
1252 
1253 	token = sbitmap_get(&sdev->budget_map);
1254 	if (atomic_read(&sdev->device_blocked)) {
1255 		if (token < 0)
1256 			goto out;
1257 
1258 		if (scsi_device_busy(sdev) > 1)
1259 			goto out_dec;
1260 
1261 		/*
1262 		 * unblock after device_blocked iterates to zero
1263 		 */
1264 		if (atomic_dec_return(&sdev->device_blocked) > 0)
1265 			goto out_dec;
1266 		SCSI_LOG_MLQUEUE(3, sdev_printk(KERN_INFO, sdev,
1267 				   "unblocking device at zero depth\n"));
1268 	}
1269 
1270 	return token;
1271 out_dec:
1272 	if (token >= 0)
1273 		sbitmap_put(&sdev->budget_map, token);
1274 out:
1275 	return -1;
1276 }
1277 
1278 /*
1279  * scsi_target_queue_ready: checks if there we can send commands to target
1280  * @sdev: scsi device on starget to check.
1281  */
scsi_target_queue_ready(struct Scsi_Host * shost,struct scsi_device * sdev)1282 static inline int scsi_target_queue_ready(struct Scsi_Host *shost,
1283 					   struct scsi_device *sdev)
1284 {
1285 	struct scsi_target *starget = scsi_target(sdev);
1286 	unsigned int busy;
1287 
1288 	if (starget->single_lun) {
1289 		spin_lock_irq(shost->host_lock);
1290 		if (starget->starget_sdev_user &&
1291 		    starget->starget_sdev_user != sdev) {
1292 			spin_unlock_irq(shost->host_lock);
1293 			return 0;
1294 		}
1295 		starget->starget_sdev_user = sdev;
1296 		spin_unlock_irq(shost->host_lock);
1297 	}
1298 
1299 	if (starget->can_queue <= 0)
1300 		return 1;
1301 
1302 	busy = atomic_inc_return(&starget->target_busy) - 1;
1303 	if (atomic_read(&starget->target_blocked) > 0) {
1304 		if (busy)
1305 			goto starved;
1306 
1307 		/*
1308 		 * unblock after target_blocked iterates to zero
1309 		 */
1310 		if (atomic_dec_return(&starget->target_blocked) > 0)
1311 			goto out_dec;
1312 
1313 		SCSI_LOG_MLQUEUE(3, starget_printk(KERN_INFO, starget,
1314 				 "unblocking target at zero depth\n"));
1315 	}
1316 
1317 	if (busy >= starget->can_queue)
1318 		goto starved;
1319 
1320 	return 1;
1321 
1322 starved:
1323 	spin_lock_irq(shost->host_lock);
1324 	list_move_tail(&sdev->starved_entry, &shost->starved_list);
1325 	spin_unlock_irq(shost->host_lock);
1326 out_dec:
1327 	if (starget->can_queue > 0)
1328 		atomic_dec(&starget->target_busy);
1329 	return 0;
1330 }
1331 
1332 /*
1333  * scsi_host_queue_ready: if we can send requests to shost, return 1 else
1334  * return 0. We must end up running the queue again whenever 0 is
1335  * returned, else IO can hang.
1336  */
scsi_host_queue_ready(struct request_queue * q,struct Scsi_Host * shost,struct scsi_device * sdev,struct scsi_cmnd * cmd)1337 static inline int scsi_host_queue_ready(struct request_queue *q,
1338 				   struct Scsi_Host *shost,
1339 				   struct scsi_device *sdev,
1340 				   struct scsi_cmnd *cmd)
1341 {
1342 	if (atomic_read(&shost->host_blocked) > 0) {
1343 		if (scsi_host_busy(shost) > 0)
1344 			goto starved;
1345 
1346 		/*
1347 		 * unblock after host_blocked iterates to zero
1348 		 */
1349 		if (atomic_dec_return(&shost->host_blocked) > 0)
1350 			goto out_dec;
1351 
1352 		SCSI_LOG_MLQUEUE(3,
1353 			shost_printk(KERN_INFO, shost,
1354 				     "unblocking host at zero depth\n"));
1355 	}
1356 
1357 	if (shost->host_self_blocked)
1358 		goto starved;
1359 
1360 	/* We're OK to process the command, so we can't be starved */
1361 	if (!list_empty(&sdev->starved_entry)) {
1362 		spin_lock_irq(shost->host_lock);
1363 		if (!list_empty(&sdev->starved_entry))
1364 			list_del_init(&sdev->starved_entry);
1365 		spin_unlock_irq(shost->host_lock);
1366 	}
1367 
1368 	__set_bit(SCMD_STATE_INFLIGHT, &cmd->state);
1369 
1370 	return 1;
1371 
1372 starved:
1373 	spin_lock_irq(shost->host_lock);
1374 	if (list_empty(&sdev->starved_entry))
1375 		list_add_tail(&sdev->starved_entry, &shost->starved_list);
1376 	spin_unlock_irq(shost->host_lock);
1377 out_dec:
1378 	scsi_dec_host_busy(shost, cmd);
1379 	return 0;
1380 }
1381 
1382 /*
1383  * Busy state exporting function for request stacking drivers.
1384  *
1385  * For efficiency, no lock is taken to check the busy state of
1386  * shost/starget/sdev, since the returned value is not guaranteed and
1387  * may be changed after request stacking drivers call the function,
1388  * regardless of taking lock or not.
1389  *
1390  * When scsi can't dispatch I/Os anymore and needs to kill I/Os scsi
1391  * needs to return 'not busy'. Otherwise, request stacking drivers
1392  * may hold requests forever.
1393  */
scsi_mq_lld_busy(struct request_queue * q)1394 static bool scsi_mq_lld_busy(struct request_queue *q)
1395 {
1396 	struct scsi_device *sdev = q->queuedata;
1397 	struct Scsi_Host *shost;
1398 
1399 	if (blk_queue_dying(q))
1400 		return false;
1401 
1402 	shost = sdev->host;
1403 
1404 	/*
1405 	 * Ignore host/starget busy state.
1406 	 * Since block layer does not have a concept of fairness across
1407 	 * multiple queues, congestion of host/starget needs to be handled
1408 	 * in SCSI layer.
1409 	 */
1410 	if (scsi_host_in_recovery(shost) || scsi_device_is_busy(sdev))
1411 		return true;
1412 
1413 	return false;
1414 }
1415 
1416 /*
1417  * Block layer request completion callback. May be called from interrupt
1418  * context.
1419  */
scsi_complete(struct request * rq)1420 static void scsi_complete(struct request *rq)
1421 {
1422 	struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(rq);
1423 	enum scsi_disposition disposition;
1424 
1425 	INIT_LIST_HEAD(&cmd->eh_entry);
1426 
1427 	atomic_inc(&cmd->device->iodone_cnt);
1428 	if (cmd->result)
1429 		atomic_inc(&cmd->device->ioerr_cnt);
1430 
1431 	disposition = scsi_decide_disposition(cmd);
1432 	if (disposition != SUCCESS && scsi_cmd_runtime_exceeced(cmd))
1433 		disposition = SUCCESS;
1434 
1435 	scsi_log_completion(cmd, disposition);
1436 
1437 	switch (disposition) {
1438 	case SUCCESS:
1439 		scsi_finish_command(cmd);
1440 		break;
1441 	case NEEDS_RETRY:
1442 		scsi_queue_insert(cmd, SCSI_MLQUEUE_EH_RETRY);
1443 		break;
1444 	case ADD_TO_MLQUEUE:
1445 		scsi_queue_insert(cmd, SCSI_MLQUEUE_DEVICE_BUSY);
1446 		break;
1447 	default:
1448 		scsi_eh_scmd_add(cmd);
1449 		break;
1450 	}
1451 }
1452 
1453 /**
1454  * scsi_dispatch_cmd - Dispatch a command to the low-level driver.
1455  * @cmd: command block we are dispatching.
1456  *
1457  * Return: nonzero return request was rejected and device's queue needs to be
1458  * plugged.
1459  */
scsi_dispatch_cmd(struct scsi_cmnd * cmd)1460 static int scsi_dispatch_cmd(struct scsi_cmnd *cmd)
1461 {
1462 	struct Scsi_Host *host = cmd->device->host;
1463 	int rtn = 0;
1464 
1465 	atomic_inc(&cmd->device->iorequest_cnt);
1466 
1467 	/* check if the device is still usable */
1468 	if (unlikely(cmd->device->sdev_state == SDEV_DEL)) {
1469 		/* in SDEV_DEL we error all commands. DID_NO_CONNECT
1470 		 * returns an immediate error upwards, and signals
1471 		 * that the device is no longer present */
1472 		cmd->result = DID_NO_CONNECT << 16;
1473 		goto done;
1474 	}
1475 
1476 	/* Check to see if the scsi lld made this device blocked. */
1477 	if (unlikely(scsi_device_blocked(cmd->device))) {
1478 		/*
1479 		 * in blocked state, the command is just put back on
1480 		 * the device queue.  The suspend state has already
1481 		 * blocked the queue so future requests should not
1482 		 * occur until the device transitions out of the
1483 		 * suspend state.
1484 		 */
1485 		SCSI_LOG_MLQUEUE(3, scmd_printk(KERN_INFO, cmd,
1486 			"queuecommand : device blocked\n"));
1487 		atomic_dec(&cmd->device->iorequest_cnt);
1488 		return SCSI_MLQUEUE_DEVICE_BUSY;
1489 	}
1490 
1491 	/* Store the LUN value in cmnd, if needed. */
1492 	if (cmd->device->lun_in_cdb)
1493 		cmd->cmnd[1] = (cmd->cmnd[1] & 0x1f) |
1494 			       (cmd->device->lun << 5 & 0xe0);
1495 
1496 	scsi_log_send(cmd);
1497 
1498 	/*
1499 	 * Before we queue this command, check if the command
1500 	 * length exceeds what the host adapter can handle.
1501 	 */
1502 	if (cmd->cmd_len > cmd->device->host->max_cmd_len) {
1503 		SCSI_LOG_MLQUEUE(3, scmd_printk(KERN_INFO, cmd,
1504 			       "queuecommand : command too long. "
1505 			       "cdb_size=%d host->max_cmd_len=%d\n",
1506 			       cmd->cmd_len, cmd->device->host->max_cmd_len));
1507 		cmd->result = (DID_ABORT << 16);
1508 		goto done;
1509 	}
1510 
1511 	if (unlikely(host->shost_state == SHOST_DEL)) {
1512 		cmd->result = (DID_NO_CONNECT << 16);
1513 		goto done;
1514 
1515 	}
1516 
1517 	trace_scsi_dispatch_cmd_start(cmd);
1518 	rtn = host->hostt->queuecommand(host, cmd);
1519 	if (rtn) {
1520 		atomic_dec(&cmd->device->iorequest_cnt);
1521 		trace_scsi_dispatch_cmd_error(cmd, rtn);
1522 		if (rtn != SCSI_MLQUEUE_DEVICE_BUSY &&
1523 		    rtn != SCSI_MLQUEUE_TARGET_BUSY)
1524 			rtn = SCSI_MLQUEUE_HOST_BUSY;
1525 
1526 		SCSI_LOG_MLQUEUE(3, scmd_printk(KERN_INFO, cmd,
1527 			"queuecommand : request rejected\n"));
1528 	}
1529 
1530 	return rtn;
1531  done:
1532 	scsi_done(cmd);
1533 	return 0;
1534 }
1535 
1536 /* Size in bytes of the sg-list stored in the scsi-mq command-private data. */
scsi_mq_inline_sgl_size(struct Scsi_Host * shost)1537 static unsigned int scsi_mq_inline_sgl_size(struct Scsi_Host *shost)
1538 {
1539 	return min_t(unsigned int, shost->sg_tablesize, SCSI_INLINE_SG_CNT) *
1540 		sizeof(struct scatterlist);
1541 }
1542 
scsi_prepare_cmd(struct request * req)1543 static blk_status_t scsi_prepare_cmd(struct request *req)
1544 {
1545 	struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req);
1546 	struct scsi_device *sdev = req->q->queuedata;
1547 	struct Scsi_Host *shost = sdev->host;
1548 	bool in_flight = test_bit(SCMD_STATE_INFLIGHT, &cmd->state);
1549 	struct scatterlist *sg;
1550 
1551 	scsi_init_command(sdev, cmd);
1552 
1553 	cmd->eh_eflags = 0;
1554 	cmd->prot_type = 0;
1555 	cmd->prot_flags = 0;
1556 	cmd->submitter = 0;
1557 	memset(&cmd->sdb, 0, sizeof(cmd->sdb));
1558 	cmd->underflow = 0;
1559 	cmd->transfersize = 0;
1560 	cmd->host_scribble = NULL;
1561 	cmd->result = 0;
1562 	cmd->extra_len = 0;
1563 	cmd->state = 0;
1564 	if (in_flight)
1565 		__set_bit(SCMD_STATE_INFLIGHT, &cmd->state);
1566 
1567 	/*
1568 	 * Only clear the driver-private command data if the LLD does not supply
1569 	 * a function to initialize that data.
1570 	 */
1571 	if (!shost->hostt->init_cmd_priv)
1572 		memset(cmd + 1, 0, shost->hostt->cmd_size);
1573 
1574 	cmd->prot_op = SCSI_PROT_NORMAL;
1575 	if (blk_rq_bytes(req))
1576 		cmd->sc_data_direction = rq_dma_dir(req);
1577 	else
1578 		cmd->sc_data_direction = DMA_NONE;
1579 
1580 	sg = (void *)cmd + sizeof(struct scsi_cmnd) + shost->hostt->cmd_size;
1581 	cmd->sdb.table.sgl = sg;
1582 
1583 	if (scsi_host_get_prot(shost)) {
1584 		memset(cmd->prot_sdb, 0, sizeof(struct scsi_data_buffer));
1585 
1586 		cmd->prot_sdb->table.sgl =
1587 			(struct scatterlist *)(cmd->prot_sdb + 1);
1588 	}
1589 
1590 	/*
1591 	 * Special handling for passthrough commands, which don't go to the ULP
1592 	 * at all:
1593 	 */
1594 	if (blk_rq_is_passthrough(req))
1595 		return scsi_setup_scsi_cmnd(sdev, req);
1596 
1597 	if (sdev->handler && sdev->handler->prep_fn) {
1598 		blk_status_t ret = sdev->handler->prep_fn(sdev, req);
1599 
1600 		if (ret != BLK_STS_OK)
1601 			return ret;
1602 	}
1603 
1604 	/* Usually overridden by the ULP */
1605 	cmd->allowed = 0;
1606 	memset(cmd->cmnd, 0, sizeof(cmd->cmnd));
1607 	return scsi_cmd_to_driver(cmd)->init_command(cmd);
1608 }
1609 
scsi_done_internal(struct scsi_cmnd * cmd,bool complete_directly)1610 static void scsi_done_internal(struct scsi_cmnd *cmd, bool complete_directly)
1611 {
1612 	struct request *req = scsi_cmd_to_rq(cmd);
1613 
1614 	switch (cmd->submitter) {
1615 	case SUBMITTED_BY_BLOCK_LAYER:
1616 		break;
1617 	case SUBMITTED_BY_SCSI_ERROR_HANDLER:
1618 		return scsi_eh_done(cmd);
1619 	case SUBMITTED_BY_SCSI_RESET_IOCTL:
1620 		return;
1621 	}
1622 
1623 	if (unlikely(blk_should_fake_timeout(scsi_cmd_to_rq(cmd)->q)))
1624 		return;
1625 	if (unlikely(test_and_set_bit(SCMD_STATE_COMPLETE, &cmd->state)))
1626 		return;
1627 	trace_scsi_dispatch_cmd_done(cmd);
1628 
1629 	if (complete_directly)
1630 		blk_mq_complete_request_direct(req, scsi_complete);
1631 	else
1632 		blk_mq_complete_request(req);
1633 }
1634 
scsi_done(struct scsi_cmnd * cmd)1635 void scsi_done(struct scsi_cmnd *cmd)
1636 {
1637 	scsi_done_internal(cmd, false);
1638 }
1639 EXPORT_SYMBOL(scsi_done);
1640 
scsi_done_direct(struct scsi_cmnd * cmd)1641 void scsi_done_direct(struct scsi_cmnd *cmd)
1642 {
1643 	scsi_done_internal(cmd, true);
1644 }
1645 EXPORT_SYMBOL(scsi_done_direct);
1646 
scsi_mq_put_budget(struct request_queue * q,int budget_token)1647 static void scsi_mq_put_budget(struct request_queue *q, int budget_token)
1648 {
1649 	struct scsi_device *sdev = q->queuedata;
1650 
1651 	sbitmap_put(&sdev->budget_map, budget_token);
1652 }
1653 
1654 /*
1655  * When to reinvoke queueing after a resource shortage. It's 3 msecs to
1656  * not change behaviour from the previous unplug mechanism, experimentation
1657  * may prove this needs changing.
1658  */
1659 #define SCSI_QUEUE_DELAY 3
1660 
scsi_mq_get_budget(struct request_queue * q)1661 static int scsi_mq_get_budget(struct request_queue *q)
1662 {
1663 	struct scsi_device *sdev = q->queuedata;
1664 	int token = scsi_dev_queue_ready(q, sdev);
1665 
1666 	if (token >= 0)
1667 		return token;
1668 
1669 	atomic_inc(&sdev->restarts);
1670 
1671 	/*
1672 	 * Orders atomic_inc(&sdev->restarts) and atomic_read(&sdev->device_busy).
1673 	 * .restarts must be incremented before .device_busy is read because the
1674 	 * code in scsi_run_queue_async() depends on the order of these operations.
1675 	 */
1676 	smp_mb__after_atomic();
1677 
1678 	/*
1679 	 * If all in-flight requests originated from this LUN are completed
1680 	 * before reading .device_busy, sdev->device_busy will be observed as
1681 	 * zero, then blk_mq_delay_run_hw_queues() will dispatch this request
1682 	 * soon. Otherwise, completion of one of these requests will observe
1683 	 * the .restarts flag, and the request queue will be run for handling
1684 	 * this request, see scsi_end_request().
1685 	 */
1686 	if (unlikely(scsi_device_busy(sdev) == 0 &&
1687 				!scsi_device_blocked(sdev)))
1688 		blk_mq_delay_run_hw_queues(sdev->request_queue, SCSI_QUEUE_DELAY);
1689 	return -1;
1690 }
1691 
scsi_mq_set_rq_budget_token(struct request * req,int token)1692 static void scsi_mq_set_rq_budget_token(struct request *req, int token)
1693 {
1694 	struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req);
1695 
1696 	cmd->budget_token = token;
1697 }
1698 
scsi_mq_get_rq_budget_token(struct request * req)1699 static int scsi_mq_get_rq_budget_token(struct request *req)
1700 {
1701 	struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req);
1702 
1703 	return cmd->budget_token;
1704 }
1705 
scsi_queue_rq(struct blk_mq_hw_ctx * hctx,const struct blk_mq_queue_data * bd)1706 static blk_status_t scsi_queue_rq(struct blk_mq_hw_ctx *hctx,
1707 			 const struct blk_mq_queue_data *bd)
1708 {
1709 	struct request *req = bd->rq;
1710 	struct request_queue *q = req->q;
1711 	struct scsi_device *sdev = q->queuedata;
1712 	struct Scsi_Host *shost = sdev->host;
1713 	struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req);
1714 	blk_status_t ret;
1715 	int reason;
1716 
1717 	WARN_ON_ONCE(cmd->budget_token < 0);
1718 
1719 	/*
1720 	 * If the device is not in running state we will reject some or all
1721 	 * commands.
1722 	 */
1723 	if (unlikely(sdev->sdev_state != SDEV_RUNNING)) {
1724 		ret = scsi_device_state_check(sdev, req);
1725 		if (ret != BLK_STS_OK)
1726 			goto out_put_budget;
1727 	}
1728 
1729 	ret = BLK_STS_RESOURCE;
1730 	if (!scsi_target_queue_ready(shost, sdev))
1731 		goto out_put_budget;
1732 	if (unlikely(scsi_host_in_recovery(shost))) {
1733 		if (cmd->flags & SCMD_FAIL_IF_RECOVERING)
1734 			ret = BLK_STS_OFFLINE;
1735 		goto out_dec_target_busy;
1736 	}
1737 	if (!scsi_host_queue_ready(q, shost, sdev, cmd))
1738 		goto out_dec_target_busy;
1739 
1740 	if (!(req->rq_flags & RQF_DONTPREP)) {
1741 		ret = scsi_prepare_cmd(req);
1742 		if (ret != BLK_STS_OK)
1743 			goto out_dec_host_busy;
1744 		req->rq_flags |= RQF_DONTPREP;
1745 	} else {
1746 		clear_bit(SCMD_STATE_COMPLETE, &cmd->state);
1747 	}
1748 
1749 	cmd->flags &= SCMD_PRESERVED_FLAGS;
1750 	if (sdev->simple_tags)
1751 		cmd->flags |= SCMD_TAGGED;
1752 	if (bd->last)
1753 		cmd->flags |= SCMD_LAST;
1754 
1755 	scsi_set_resid(cmd, 0);
1756 	memset(cmd->sense_buffer, 0, SCSI_SENSE_BUFFERSIZE);
1757 	cmd->submitter = SUBMITTED_BY_BLOCK_LAYER;
1758 
1759 	blk_mq_start_request(req);
1760 	reason = scsi_dispatch_cmd(cmd);
1761 	if (reason) {
1762 		scsi_set_blocked(cmd, reason);
1763 		ret = BLK_STS_RESOURCE;
1764 		goto out_dec_host_busy;
1765 	}
1766 
1767 	return BLK_STS_OK;
1768 
1769 out_dec_host_busy:
1770 	scsi_dec_host_busy(shost, cmd);
1771 out_dec_target_busy:
1772 	if (scsi_target(sdev)->can_queue > 0)
1773 		atomic_dec(&scsi_target(sdev)->target_busy);
1774 out_put_budget:
1775 	scsi_mq_put_budget(q, cmd->budget_token);
1776 	cmd->budget_token = -1;
1777 	switch (ret) {
1778 	case BLK_STS_OK:
1779 		break;
1780 	case BLK_STS_RESOURCE:
1781 	case BLK_STS_ZONE_RESOURCE:
1782 		if (scsi_device_blocked(sdev))
1783 			ret = BLK_STS_DEV_RESOURCE;
1784 		break;
1785 	case BLK_STS_AGAIN:
1786 		cmd->result = DID_BUS_BUSY << 16;
1787 		if (req->rq_flags & RQF_DONTPREP)
1788 			scsi_mq_uninit_cmd(cmd);
1789 		break;
1790 	default:
1791 		if (unlikely(!scsi_device_online(sdev)))
1792 			cmd->result = DID_NO_CONNECT << 16;
1793 		else
1794 			cmd->result = DID_ERROR << 16;
1795 		/*
1796 		 * Make sure to release all allocated resources when
1797 		 * we hit an error, as we will never see this command
1798 		 * again.
1799 		 */
1800 		if (req->rq_flags & RQF_DONTPREP)
1801 			scsi_mq_uninit_cmd(cmd);
1802 		scsi_run_queue_async(sdev);
1803 		break;
1804 	}
1805 	return ret;
1806 }
1807 
scsi_mq_init_request(struct blk_mq_tag_set * set,struct request * rq,unsigned int hctx_idx,unsigned int numa_node)1808 static int scsi_mq_init_request(struct blk_mq_tag_set *set, struct request *rq,
1809 				unsigned int hctx_idx, unsigned int numa_node)
1810 {
1811 	struct Scsi_Host *shost = set->driver_data;
1812 	struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(rq);
1813 	struct scatterlist *sg;
1814 	int ret = 0;
1815 
1816 	cmd->sense_buffer =
1817 		kmem_cache_alloc_node(scsi_sense_cache, GFP_KERNEL, numa_node);
1818 	if (!cmd->sense_buffer)
1819 		return -ENOMEM;
1820 
1821 	if (scsi_host_get_prot(shost)) {
1822 		sg = (void *)cmd + sizeof(struct scsi_cmnd) +
1823 			shost->hostt->cmd_size;
1824 		cmd->prot_sdb = (void *)sg + scsi_mq_inline_sgl_size(shost);
1825 	}
1826 
1827 	if (shost->hostt->init_cmd_priv) {
1828 		ret = shost->hostt->init_cmd_priv(shost, cmd);
1829 		if (ret < 0)
1830 			kmem_cache_free(scsi_sense_cache, cmd->sense_buffer);
1831 	}
1832 
1833 	return ret;
1834 }
1835 
scsi_mq_exit_request(struct blk_mq_tag_set * set,struct request * rq,unsigned int hctx_idx)1836 static void scsi_mq_exit_request(struct blk_mq_tag_set *set, struct request *rq,
1837 				 unsigned int hctx_idx)
1838 {
1839 	struct Scsi_Host *shost = set->driver_data;
1840 	struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(rq);
1841 
1842 	if (shost->hostt->exit_cmd_priv)
1843 		shost->hostt->exit_cmd_priv(shost, cmd);
1844 	kmem_cache_free(scsi_sense_cache, cmd->sense_buffer);
1845 }
1846 
1847 
scsi_mq_poll(struct blk_mq_hw_ctx * hctx,struct io_comp_batch * iob)1848 static int scsi_mq_poll(struct blk_mq_hw_ctx *hctx, struct io_comp_batch *iob)
1849 {
1850 	struct Scsi_Host *shost = hctx->driver_data;
1851 
1852 	if (shost->hostt->mq_poll)
1853 		return shost->hostt->mq_poll(shost, hctx->queue_num);
1854 
1855 	return 0;
1856 }
1857 
scsi_init_hctx(struct blk_mq_hw_ctx * hctx,void * data,unsigned int hctx_idx)1858 static int scsi_init_hctx(struct blk_mq_hw_ctx *hctx, void *data,
1859 			  unsigned int hctx_idx)
1860 {
1861 	struct Scsi_Host *shost = data;
1862 
1863 	hctx->driver_data = shost;
1864 	return 0;
1865 }
1866 
scsi_map_queues(struct blk_mq_tag_set * set)1867 static void scsi_map_queues(struct blk_mq_tag_set *set)
1868 {
1869 	struct Scsi_Host *shost = container_of(set, struct Scsi_Host, tag_set);
1870 
1871 	if (shost->hostt->map_queues)
1872 		return shost->hostt->map_queues(shost);
1873 	blk_mq_map_queues(&set->map[HCTX_TYPE_DEFAULT]);
1874 }
1875 
__scsi_init_queue(struct Scsi_Host * shost,struct request_queue * q)1876 void __scsi_init_queue(struct Scsi_Host *shost, struct request_queue *q)
1877 {
1878 	struct device *dev = shost->dma_dev;
1879 
1880 	/*
1881 	 * this limit is imposed by hardware restrictions
1882 	 */
1883 	blk_queue_max_segments(q, min_t(unsigned short, shost->sg_tablesize,
1884 					SG_MAX_SEGMENTS));
1885 
1886 	if (scsi_host_prot_dma(shost)) {
1887 		shost->sg_prot_tablesize =
1888 			min_not_zero(shost->sg_prot_tablesize,
1889 				     (unsigned short)SCSI_MAX_PROT_SG_SEGMENTS);
1890 		BUG_ON(shost->sg_prot_tablesize < shost->sg_tablesize);
1891 		blk_queue_max_integrity_segments(q, shost->sg_prot_tablesize);
1892 	}
1893 
1894 	blk_queue_max_hw_sectors(q, shost->max_sectors);
1895 	blk_queue_segment_boundary(q, shost->dma_boundary);
1896 	dma_set_seg_boundary(dev, shost->dma_boundary);
1897 
1898 	blk_queue_max_segment_size(q, shost->max_segment_size);
1899 	blk_queue_virt_boundary(q, shost->virt_boundary_mask);
1900 	dma_set_max_seg_size(dev, queue_max_segment_size(q));
1901 
1902 	/*
1903 	 * Set a reasonable default alignment:  The larger of 32-byte (dword),
1904 	 * which is a common minimum for HBAs, and the minimum DMA alignment,
1905 	 * which is set by the platform.
1906 	 *
1907 	 * Devices that require a bigger alignment can increase it later.
1908 	 */
1909 	blk_queue_dma_alignment(q, max(4, dma_get_cache_alignment()) - 1);
1910 }
1911 EXPORT_SYMBOL_GPL(__scsi_init_queue);
1912 
1913 static const struct blk_mq_ops scsi_mq_ops_no_commit = {
1914 	.get_budget	= scsi_mq_get_budget,
1915 	.put_budget	= scsi_mq_put_budget,
1916 	.queue_rq	= scsi_queue_rq,
1917 	.complete	= scsi_complete,
1918 	.timeout	= scsi_timeout,
1919 #ifdef CONFIG_BLK_DEBUG_FS
1920 	.show_rq	= scsi_show_rq,
1921 #endif
1922 	.init_request	= scsi_mq_init_request,
1923 	.exit_request	= scsi_mq_exit_request,
1924 	.cleanup_rq	= scsi_cleanup_rq,
1925 	.busy		= scsi_mq_lld_busy,
1926 	.map_queues	= scsi_map_queues,
1927 	.init_hctx	= scsi_init_hctx,
1928 	.poll		= scsi_mq_poll,
1929 	.set_rq_budget_token = scsi_mq_set_rq_budget_token,
1930 	.get_rq_budget_token = scsi_mq_get_rq_budget_token,
1931 };
1932 
1933 
scsi_commit_rqs(struct blk_mq_hw_ctx * hctx)1934 static void scsi_commit_rqs(struct blk_mq_hw_ctx *hctx)
1935 {
1936 	struct Scsi_Host *shost = hctx->driver_data;
1937 
1938 	shost->hostt->commit_rqs(shost, hctx->queue_num);
1939 }
1940 
1941 static const struct blk_mq_ops scsi_mq_ops = {
1942 	.get_budget	= scsi_mq_get_budget,
1943 	.put_budget	= scsi_mq_put_budget,
1944 	.queue_rq	= scsi_queue_rq,
1945 	.commit_rqs	= scsi_commit_rqs,
1946 	.complete	= scsi_complete,
1947 	.timeout	= scsi_timeout,
1948 #ifdef CONFIG_BLK_DEBUG_FS
1949 	.show_rq	= scsi_show_rq,
1950 #endif
1951 	.init_request	= scsi_mq_init_request,
1952 	.exit_request	= scsi_mq_exit_request,
1953 	.cleanup_rq	= scsi_cleanup_rq,
1954 	.busy		= scsi_mq_lld_busy,
1955 	.map_queues	= scsi_map_queues,
1956 	.init_hctx	= scsi_init_hctx,
1957 	.poll		= scsi_mq_poll,
1958 	.set_rq_budget_token = scsi_mq_set_rq_budget_token,
1959 	.get_rq_budget_token = scsi_mq_get_rq_budget_token,
1960 };
1961 
scsi_mq_setup_tags(struct Scsi_Host * shost)1962 int scsi_mq_setup_tags(struct Scsi_Host *shost)
1963 {
1964 	unsigned int cmd_size, sgl_size;
1965 	struct blk_mq_tag_set *tag_set = &shost->tag_set;
1966 
1967 	sgl_size = max_t(unsigned int, sizeof(struct scatterlist),
1968 				scsi_mq_inline_sgl_size(shost));
1969 	cmd_size = sizeof(struct scsi_cmnd) + shost->hostt->cmd_size + sgl_size;
1970 	if (scsi_host_get_prot(shost))
1971 		cmd_size += sizeof(struct scsi_data_buffer) +
1972 			sizeof(struct scatterlist) * SCSI_INLINE_PROT_SG_CNT;
1973 
1974 	memset(tag_set, 0, sizeof(*tag_set));
1975 	if (shost->hostt->commit_rqs)
1976 		tag_set->ops = &scsi_mq_ops;
1977 	else
1978 		tag_set->ops = &scsi_mq_ops_no_commit;
1979 	tag_set->nr_hw_queues = shost->nr_hw_queues ? : 1;
1980 	tag_set->nr_maps = shost->nr_maps ? : 1;
1981 	tag_set->queue_depth = shost->can_queue;
1982 	tag_set->cmd_size = cmd_size;
1983 	tag_set->numa_node = dev_to_node(shost->dma_dev);
1984 	tag_set->flags = BLK_MQ_F_SHOULD_MERGE;
1985 	tag_set->flags |=
1986 		BLK_ALLOC_POLICY_TO_MQ_FLAG(shost->hostt->tag_alloc_policy);
1987 	if (shost->queuecommand_may_block)
1988 		tag_set->flags |= BLK_MQ_F_BLOCKING;
1989 	tag_set->driver_data = shost;
1990 	if (shost->host_tagset)
1991 		tag_set->flags |= BLK_MQ_F_TAG_HCTX_SHARED;
1992 
1993 	return blk_mq_alloc_tag_set(tag_set);
1994 }
1995 
scsi_mq_free_tags(struct kref * kref)1996 void scsi_mq_free_tags(struct kref *kref)
1997 {
1998 	struct Scsi_Host *shost = container_of(kref, typeof(*shost),
1999 					       tagset_refcnt);
2000 
2001 	blk_mq_free_tag_set(&shost->tag_set);
2002 	complete(&shost->tagset_freed);
2003 }
2004 
2005 /**
2006  * scsi_device_from_queue - return sdev associated with a request_queue
2007  * @q: The request queue to return the sdev from
2008  *
2009  * Return the sdev associated with a request queue or NULL if the
2010  * request_queue does not reference a SCSI device.
2011  */
scsi_device_from_queue(struct request_queue * q)2012 struct scsi_device *scsi_device_from_queue(struct request_queue *q)
2013 {
2014 	struct scsi_device *sdev = NULL;
2015 
2016 	if (q->mq_ops == &scsi_mq_ops_no_commit ||
2017 	    q->mq_ops == &scsi_mq_ops)
2018 		sdev = q->queuedata;
2019 	if (!sdev || !get_device(&sdev->sdev_gendev))
2020 		sdev = NULL;
2021 
2022 	return sdev;
2023 }
2024 /*
2025  * pktcdvd should have been integrated into the SCSI layers, but for historical
2026  * reasons like the old IDE driver it isn't.  This export allows it to safely
2027  * probe if a given device is a SCSI one and only attach to that.
2028  */
2029 #ifdef CONFIG_CDROM_PKTCDVD_MODULE
2030 EXPORT_SYMBOL_GPL(scsi_device_from_queue);
2031 #endif
2032 
2033 /**
2034  * scsi_block_requests - Utility function used by low-level drivers to prevent
2035  * further commands from being queued to the device.
2036  * @shost:  host in question
2037  *
2038  * There is no timer nor any other means by which the requests get unblocked
2039  * other than the low-level driver calling scsi_unblock_requests().
2040  */
scsi_block_requests(struct Scsi_Host * shost)2041 void scsi_block_requests(struct Scsi_Host *shost)
2042 {
2043 	shost->host_self_blocked = 1;
2044 }
2045 EXPORT_SYMBOL(scsi_block_requests);
2046 
2047 /**
2048  * scsi_unblock_requests - Utility function used by low-level drivers to allow
2049  * further commands to be queued to the device.
2050  * @shost:  host in question
2051  *
2052  * There is no timer nor any other means by which the requests get unblocked
2053  * other than the low-level driver calling scsi_unblock_requests(). This is done
2054  * as an API function so that changes to the internals of the scsi mid-layer
2055  * won't require wholesale changes to drivers that use this feature.
2056  */
scsi_unblock_requests(struct Scsi_Host * shost)2057 void scsi_unblock_requests(struct Scsi_Host *shost)
2058 {
2059 	shost->host_self_blocked = 0;
2060 	scsi_run_host_queues(shost);
2061 }
2062 EXPORT_SYMBOL(scsi_unblock_requests);
2063 
scsi_exit_queue(void)2064 void scsi_exit_queue(void)
2065 {
2066 	kmem_cache_destroy(scsi_sense_cache);
2067 }
2068 
2069 /**
2070  *	scsi_mode_select - issue a mode select
2071  *	@sdev:	SCSI device to be queried
2072  *	@pf:	Page format bit (1 == standard, 0 == vendor specific)
2073  *	@sp:	Save page bit (0 == don't save, 1 == save)
2074  *	@buffer: request buffer (may not be smaller than eight bytes)
2075  *	@len:	length of request buffer.
2076  *	@timeout: command timeout
2077  *	@retries: number of retries before failing
2078  *	@data: returns a structure abstracting the mode header data
2079  *	@sshdr: place to put sense data (or NULL if no sense to be collected).
2080  *		must be SCSI_SENSE_BUFFERSIZE big.
2081  *
2082  *	Returns zero if successful; negative error number or scsi
2083  *	status on error
2084  *
2085  */
scsi_mode_select(struct scsi_device * sdev,int pf,int sp,unsigned char * buffer,int len,int timeout,int retries,struct scsi_mode_data * data,struct scsi_sense_hdr * sshdr)2086 int scsi_mode_select(struct scsi_device *sdev, int pf, int sp,
2087 		     unsigned char *buffer, int len, int timeout, int retries,
2088 		     struct scsi_mode_data *data, struct scsi_sense_hdr *sshdr)
2089 {
2090 	unsigned char cmd[10];
2091 	unsigned char *real_buffer;
2092 	const struct scsi_exec_args exec_args = {
2093 		.sshdr = sshdr,
2094 	};
2095 	int ret;
2096 
2097 	memset(cmd, 0, sizeof(cmd));
2098 	cmd[1] = (pf ? 0x10 : 0) | (sp ? 0x01 : 0);
2099 
2100 	/*
2101 	 * Use MODE SELECT(10) if the device asked for it or if the mode page
2102 	 * and the mode select header cannot fit within the maximumm 255 bytes
2103 	 * of the MODE SELECT(6) command.
2104 	 */
2105 	if (sdev->use_10_for_ms ||
2106 	    len + 4 > 255 ||
2107 	    data->block_descriptor_length > 255) {
2108 		if (len > 65535 - 8)
2109 			return -EINVAL;
2110 		real_buffer = kmalloc(8 + len, GFP_KERNEL);
2111 		if (!real_buffer)
2112 			return -ENOMEM;
2113 		memcpy(real_buffer + 8, buffer, len);
2114 		len += 8;
2115 		real_buffer[0] = 0;
2116 		real_buffer[1] = 0;
2117 		real_buffer[2] = data->medium_type;
2118 		real_buffer[3] = data->device_specific;
2119 		real_buffer[4] = data->longlba ? 0x01 : 0;
2120 		real_buffer[5] = 0;
2121 		put_unaligned_be16(data->block_descriptor_length,
2122 				   &real_buffer[6]);
2123 
2124 		cmd[0] = MODE_SELECT_10;
2125 		put_unaligned_be16(len, &cmd[7]);
2126 	} else {
2127 		if (data->longlba)
2128 			return -EINVAL;
2129 
2130 		real_buffer = kmalloc(4 + len, GFP_KERNEL);
2131 		if (!real_buffer)
2132 			return -ENOMEM;
2133 		memcpy(real_buffer + 4, buffer, len);
2134 		len += 4;
2135 		real_buffer[0] = 0;
2136 		real_buffer[1] = data->medium_type;
2137 		real_buffer[2] = data->device_specific;
2138 		real_buffer[3] = data->block_descriptor_length;
2139 
2140 		cmd[0] = MODE_SELECT;
2141 		cmd[4] = len;
2142 	}
2143 
2144 	ret = scsi_execute_cmd(sdev, cmd, REQ_OP_DRV_OUT, real_buffer, len,
2145 			       timeout, retries, &exec_args);
2146 	kfree(real_buffer);
2147 	return ret;
2148 }
2149 EXPORT_SYMBOL_GPL(scsi_mode_select);
2150 
2151 /**
2152  *	scsi_mode_sense - issue a mode sense, falling back from 10 to six bytes if necessary.
2153  *	@sdev:	SCSI device to be queried
2154  *	@dbd:	set to prevent mode sense from returning block descriptors
2155  *	@modepage: mode page being requested
2156  *	@subpage: sub-page of the mode page being requested
2157  *	@buffer: request buffer (may not be smaller than eight bytes)
2158  *	@len:	length of request buffer.
2159  *	@timeout: command timeout
2160  *	@retries: number of retries before failing
2161  *	@data: returns a structure abstracting the mode header data
2162  *	@sshdr: place to put sense data (or NULL if no sense to be collected).
2163  *		must be SCSI_SENSE_BUFFERSIZE big.
2164  *
2165  *	Returns zero if successful, or a negative error number on failure
2166  */
2167 int
scsi_mode_sense(struct scsi_device * sdev,int dbd,int modepage,int subpage,unsigned char * buffer,int len,int timeout,int retries,struct scsi_mode_data * data,struct scsi_sense_hdr * sshdr)2168 scsi_mode_sense(struct scsi_device *sdev, int dbd, int modepage, int subpage,
2169 		  unsigned char *buffer, int len, int timeout, int retries,
2170 		  struct scsi_mode_data *data, struct scsi_sense_hdr *sshdr)
2171 {
2172 	unsigned char cmd[12];
2173 	int use_10_for_ms;
2174 	int header_length;
2175 	int result, retry_count = retries;
2176 	struct scsi_sense_hdr my_sshdr;
2177 	const struct scsi_exec_args exec_args = {
2178 		/* caller might not be interested in sense, but we need it */
2179 		.sshdr = sshdr ? : &my_sshdr,
2180 	};
2181 
2182 	memset(data, 0, sizeof(*data));
2183 	memset(&cmd[0], 0, 12);
2184 
2185 	dbd = sdev->set_dbd_for_ms ? 8 : dbd;
2186 	cmd[1] = dbd & 0x18;	/* allows DBD and LLBA bits */
2187 	cmd[2] = modepage;
2188 	cmd[3] = subpage;
2189 
2190 	sshdr = exec_args.sshdr;
2191 
2192  retry:
2193 	use_10_for_ms = sdev->use_10_for_ms || len > 255;
2194 
2195 	if (use_10_for_ms) {
2196 		if (len < 8 || len > 65535)
2197 			return -EINVAL;
2198 
2199 		cmd[0] = MODE_SENSE_10;
2200 		put_unaligned_be16(len, &cmd[7]);
2201 		header_length = 8;
2202 	} else {
2203 		if (len < 4)
2204 			return -EINVAL;
2205 
2206 		cmd[0] = MODE_SENSE;
2207 		cmd[4] = len;
2208 		header_length = 4;
2209 	}
2210 
2211 	memset(buffer, 0, len);
2212 
2213 	result = scsi_execute_cmd(sdev, cmd, REQ_OP_DRV_IN, buffer, len,
2214 				  timeout, retries, &exec_args);
2215 	if (result < 0)
2216 		return result;
2217 
2218 	/* This code looks awful: what it's doing is making sure an
2219 	 * ILLEGAL REQUEST sense return identifies the actual command
2220 	 * byte as the problem.  MODE_SENSE commands can return
2221 	 * ILLEGAL REQUEST if the code page isn't supported */
2222 
2223 	if (!scsi_status_is_good(result)) {
2224 		if (scsi_sense_valid(sshdr)) {
2225 			if ((sshdr->sense_key == ILLEGAL_REQUEST) &&
2226 			    (sshdr->asc == 0x20) && (sshdr->ascq == 0)) {
2227 				/*
2228 				 * Invalid command operation code: retry using
2229 				 * MODE SENSE(6) if this was a MODE SENSE(10)
2230 				 * request, except if the request mode page is
2231 				 * too large for MODE SENSE single byte
2232 				 * allocation length field.
2233 				 */
2234 				if (use_10_for_ms) {
2235 					if (len > 255)
2236 						return -EIO;
2237 					sdev->use_10_for_ms = 0;
2238 					goto retry;
2239 				}
2240 			}
2241 			if (scsi_status_is_check_condition(result) &&
2242 			    sshdr->sense_key == UNIT_ATTENTION &&
2243 			    retry_count) {
2244 				retry_count--;
2245 				goto retry;
2246 			}
2247 		}
2248 		return -EIO;
2249 	}
2250 	if (unlikely(buffer[0] == 0x86 && buffer[1] == 0x0b &&
2251 		     (modepage == 6 || modepage == 8))) {
2252 		/* Initio breakage? */
2253 		header_length = 0;
2254 		data->length = 13;
2255 		data->medium_type = 0;
2256 		data->device_specific = 0;
2257 		data->longlba = 0;
2258 		data->block_descriptor_length = 0;
2259 	} else if (use_10_for_ms) {
2260 		data->length = get_unaligned_be16(&buffer[0]) + 2;
2261 		data->medium_type = buffer[2];
2262 		data->device_specific = buffer[3];
2263 		data->longlba = buffer[4] & 0x01;
2264 		data->block_descriptor_length = get_unaligned_be16(&buffer[6]);
2265 	} else {
2266 		data->length = buffer[0] + 1;
2267 		data->medium_type = buffer[1];
2268 		data->device_specific = buffer[2];
2269 		data->block_descriptor_length = buffer[3];
2270 	}
2271 	data->header_length = header_length;
2272 
2273 	return 0;
2274 }
2275 EXPORT_SYMBOL(scsi_mode_sense);
2276 
2277 /**
2278  *	scsi_test_unit_ready - test if unit is ready
2279  *	@sdev:	scsi device to change the state of.
2280  *	@timeout: command timeout
2281  *	@retries: number of retries before failing
2282  *	@sshdr: outpout pointer for decoded sense information.
2283  *
2284  *	Returns zero if unsuccessful or an error if TUR failed.  For
2285  *	removable media, UNIT_ATTENTION sets ->changed flag.
2286  **/
2287 int
scsi_test_unit_ready(struct scsi_device * sdev,int timeout,int retries,struct scsi_sense_hdr * sshdr)2288 scsi_test_unit_ready(struct scsi_device *sdev, int timeout, int retries,
2289 		     struct scsi_sense_hdr *sshdr)
2290 {
2291 	char cmd[] = {
2292 		TEST_UNIT_READY, 0, 0, 0, 0, 0,
2293 	};
2294 	const struct scsi_exec_args exec_args = {
2295 		.sshdr = sshdr,
2296 	};
2297 	int result;
2298 
2299 	/* try to eat the UNIT_ATTENTION if there are enough retries */
2300 	do {
2301 		result = scsi_execute_cmd(sdev, cmd, REQ_OP_DRV_IN, NULL, 0,
2302 					  timeout, 1, &exec_args);
2303 		if (sdev->removable && scsi_sense_valid(sshdr) &&
2304 		    sshdr->sense_key == UNIT_ATTENTION)
2305 			sdev->changed = 1;
2306 	} while (scsi_sense_valid(sshdr) &&
2307 		 sshdr->sense_key == UNIT_ATTENTION && --retries);
2308 
2309 	return result;
2310 }
2311 EXPORT_SYMBOL(scsi_test_unit_ready);
2312 
2313 /**
2314  *	scsi_device_set_state - Take the given device through the device state model.
2315  *	@sdev:	scsi device to change the state of.
2316  *	@state:	state to change to.
2317  *
2318  *	Returns zero if successful or an error if the requested
2319  *	transition is illegal.
2320  */
2321 int
scsi_device_set_state(struct scsi_device * sdev,enum scsi_device_state state)2322 scsi_device_set_state(struct scsi_device *sdev, enum scsi_device_state state)
2323 {
2324 	enum scsi_device_state oldstate = sdev->sdev_state;
2325 
2326 	if (state == oldstate)
2327 		return 0;
2328 
2329 	switch (state) {
2330 	case SDEV_CREATED:
2331 		switch (oldstate) {
2332 		case SDEV_CREATED_BLOCK:
2333 			break;
2334 		default:
2335 			goto illegal;
2336 		}
2337 		break;
2338 
2339 	case SDEV_RUNNING:
2340 		switch (oldstate) {
2341 		case SDEV_CREATED:
2342 		case SDEV_OFFLINE:
2343 		case SDEV_TRANSPORT_OFFLINE:
2344 		case SDEV_QUIESCE:
2345 		case SDEV_BLOCK:
2346 			break;
2347 		default:
2348 			goto illegal;
2349 		}
2350 		break;
2351 
2352 	case SDEV_QUIESCE:
2353 		switch (oldstate) {
2354 		case SDEV_RUNNING:
2355 		case SDEV_OFFLINE:
2356 		case SDEV_TRANSPORT_OFFLINE:
2357 			break;
2358 		default:
2359 			goto illegal;
2360 		}
2361 		break;
2362 
2363 	case SDEV_OFFLINE:
2364 	case SDEV_TRANSPORT_OFFLINE:
2365 		switch (oldstate) {
2366 		case SDEV_CREATED:
2367 		case SDEV_RUNNING:
2368 		case SDEV_QUIESCE:
2369 		case SDEV_BLOCK:
2370 			break;
2371 		default:
2372 			goto illegal;
2373 		}
2374 		break;
2375 
2376 	case SDEV_BLOCK:
2377 		switch (oldstate) {
2378 		case SDEV_RUNNING:
2379 		case SDEV_CREATED_BLOCK:
2380 		case SDEV_QUIESCE:
2381 		case SDEV_OFFLINE:
2382 			break;
2383 		default:
2384 			goto illegal;
2385 		}
2386 		break;
2387 
2388 	case SDEV_CREATED_BLOCK:
2389 		switch (oldstate) {
2390 		case SDEV_CREATED:
2391 			break;
2392 		default:
2393 			goto illegal;
2394 		}
2395 		break;
2396 
2397 	case SDEV_CANCEL:
2398 		switch (oldstate) {
2399 		case SDEV_CREATED:
2400 		case SDEV_RUNNING:
2401 		case SDEV_QUIESCE:
2402 		case SDEV_OFFLINE:
2403 		case SDEV_TRANSPORT_OFFLINE:
2404 			break;
2405 		default:
2406 			goto illegal;
2407 		}
2408 		break;
2409 
2410 	case SDEV_DEL:
2411 		switch (oldstate) {
2412 		case SDEV_CREATED:
2413 		case SDEV_RUNNING:
2414 		case SDEV_OFFLINE:
2415 		case SDEV_TRANSPORT_OFFLINE:
2416 		case SDEV_CANCEL:
2417 		case SDEV_BLOCK:
2418 		case SDEV_CREATED_BLOCK:
2419 			break;
2420 		default:
2421 			goto illegal;
2422 		}
2423 		break;
2424 
2425 	}
2426 	sdev->offline_already = false;
2427 	sdev->sdev_state = state;
2428 	return 0;
2429 
2430  illegal:
2431 	SCSI_LOG_ERROR_RECOVERY(1,
2432 				sdev_printk(KERN_ERR, sdev,
2433 					    "Illegal state transition %s->%s",
2434 					    scsi_device_state_name(oldstate),
2435 					    scsi_device_state_name(state))
2436 				);
2437 	return -EINVAL;
2438 }
2439 EXPORT_SYMBOL(scsi_device_set_state);
2440 
2441 /**
2442  *	scsi_evt_emit - emit a single SCSI device uevent
2443  *	@sdev: associated SCSI device
2444  *	@evt: event to emit
2445  *
2446  *	Send a single uevent (scsi_event) to the associated scsi_device.
2447  */
scsi_evt_emit(struct scsi_device * sdev,struct scsi_event * evt)2448 static void scsi_evt_emit(struct scsi_device *sdev, struct scsi_event *evt)
2449 {
2450 	int idx = 0;
2451 	char *envp[3];
2452 
2453 	switch (evt->evt_type) {
2454 	case SDEV_EVT_MEDIA_CHANGE:
2455 		envp[idx++] = "SDEV_MEDIA_CHANGE=1";
2456 		break;
2457 	case SDEV_EVT_INQUIRY_CHANGE_REPORTED:
2458 		scsi_rescan_device(sdev);
2459 		envp[idx++] = "SDEV_UA=INQUIRY_DATA_HAS_CHANGED";
2460 		break;
2461 	case SDEV_EVT_CAPACITY_CHANGE_REPORTED:
2462 		envp[idx++] = "SDEV_UA=CAPACITY_DATA_HAS_CHANGED";
2463 		break;
2464 	case SDEV_EVT_SOFT_THRESHOLD_REACHED_REPORTED:
2465 	       envp[idx++] = "SDEV_UA=THIN_PROVISIONING_SOFT_THRESHOLD_REACHED";
2466 		break;
2467 	case SDEV_EVT_MODE_PARAMETER_CHANGE_REPORTED:
2468 		envp[idx++] = "SDEV_UA=MODE_PARAMETERS_CHANGED";
2469 		break;
2470 	case SDEV_EVT_LUN_CHANGE_REPORTED:
2471 		envp[idx++] = "SDEV_UA=REPORTED_LUNS_DATA_HAS_CHANGED";
2472 		break;
2473 	case SDEV_EVT_ALUA_STATE_CHANGE_REPORTED:
2474 		envp[idx++] = "SDEV_UA=ASYMMETRIC_ACCESS_STATE_CHANGED";
2475 		break;
2476 	case SDEV_EVT_POWER_ON_RESET_OCCURRED:
2477 		envp[idx++] = "SDEV_UA=POWER_ON_RESET_OCCURRED";
2478 		break;
2479 	default:
2480 		/* do nothing */
2481 		break;
2482 	}
2483 
2484 	envp[idx++] = NULL;
2485 
2486 	kobject_uevent_env(&sdev->sdev_gendev.kobj, KOBJ_CHANGE, envp);
2487 }
2488 
2489 /**
2490  *	scsi_evt_thread - send a uevent for each scsi event
2491  *	@work: work struct for scsi_device
2492  *
2493  *	Dispatch queued events to their associated scsi_device kobjects
2494  *	as uevents.
2495  */
scsi_evt_thread(struct work_struct * work)2496 void scsi_evt_thread(struct work_struct *work)
2497 {
2498 	struct scsi_device *sdev;
2499 	enum scsi_device_event evt_type;
2500 	LIST_HEAD(event_list);
2501 
2502 	sdev = container_of(work, struct scsi_device, event_work);
2503 
2504 	for (evt_type = SDEV_EVT_FIRST; evt_type <= SDEV_EVT_LAST; evt_type++)
2505 		if (test_and_clear_bit(evt_type, sdev->pending_events))
2506 			sdev_evt_send_simple(sdev, evt_type, GFP_KERNEL);
2507 
2508 	while (1) {
2509 		struct scsi_event *evt;
2510 		struct list_head *this, *tmp;
2511 		unsigned long flags;
2512 
2513 		spin_lock_irqsave(&sdev->list_lock, flags);
2514 		list_splice_init(&sdev->event_list, &event_list);
2515 		spin_unlock_irqrestore(&sdev->list_lock, flags);
2516 
2517 		if (list_empty(&event_list))
2518 			break;
2519 
2520 		list_for_each_safe(this, tmp, &event_list) {
2521 			evt = list_entry(this, struct scsi_event, node);
2522 			list_del(&evt->node);
2523 			scsi_evt_emit(sdev, evt);
2524 			kfree(evt);
2525 		}
2526 	}
2527 }
2528 
2529 /**
2530  * 	sdev_evt_send - send asserted event to uevent thread
2531  *	@sdev: scsi_device event occurred on
2532  *	@evt: event to send
2533  *
2534  *	Assert scsi device event asynchronously.
2535  */
sdev_evt_send(struct scsi_device * sdev,struct scsi_event * evt)2536 void sdev_evt_send(struct scsi_device *sdev, struct scsi_event *evt)
2537 {
2538 	unsigned long flags;
2539 
2540 #if 0
2541 	/* FIXME: currently this check eliminates all media change events
2542 	 * for polled devices.  Need to update to discriminate between AN
2543 	 * and polled events */
2544 	if (!test_bit(evt->evt_type, sdev->supported_events)) {
2545 		kfree(evt);
2546 		return;
2547 	}
2548 #endif
2549 
2550 	spin_lock_irqsave(&sdev->list_lock, flags);
2551 	list_add_tail(&evt->node, &sdev->event_list);
2552 	schedule_work(&sdev->event_work);
2553 	spin_unlock_irqrestore(&sdev->list_lock, flags);
2554 }
2555 EXPORT_SYMBOL_GPL(sdev_evt_send);
2556 
2557 /**
2558  * 	sdev_evt_alloc - allocate a new scsi event
2559  *	@evt_type: type of event to allocate
2560  *	@gfpflags: GFP flags for allocation
2561  *
2562  *	Allocates and returns a new scsi_event.
2563  */
sdev_evt_alloc(enum scsi_device_event evt_type,gfp_t gfpflags)2564 struct scsi_event *sdev_evt_alloc(enum scsi_device_event evt_type,
2565 				  gfp_t gfpflags)
2566 {
2567 	struct scsi_event *evt = kzalloc(sizeof(struct scsi_event), gfpflags);
2568 	if (!evt)
2569 		return NULL;
2570 
2571 	evt->evt_type = evt_type;
2572 	INIT_LIST_HEAD(&evt->node);
2573 
2574 	/* evt_type-specific initialization, if any */
2575 	switch (evt_type) {
2576 	case SDEV_EVT_MEDIA_CHANGE:
2577 	case SDEV_EVT_INQUIRY_CHANGE_REPORTED:
2578 	case SDEV_EVT_CAPACITY_CHANGE_REPORTED:
2579 	case SDEV_EVT_SOFT_THRESHOLD_REACHED_REPORTED:
2580 	case SDEV_EVT_MODE_PARAMETER_CHANGE_REPORTED:
2581 	case SDEV_EVT_LUN_CHANGE_REPORTED:
2582 	case SDEV_EVT_ALUA_STATE_CHANGE_REPORTED:
2583 	case SDEV_EVT_POWER_ON_RESET_OCCURRED:
2584 	default:
2585 		/* do nothing */
2586 		break;
2587 	}
2588 
2589 	return evt;
2590 }
2591 EXPORT_SYMBOL_GPL(sdev_evt_alloc);
2592 
2593 /**
2594  * 	sdev_evt_send_simple - send asserted event to uevent thread
2595  *	@sdev: scsi_device event occurred on
2596  *	@evt_type: type of event to send
2597  *	@gfpflags: GFP flags for allocation
2598  *
2599  *	Assert scsi device event asynchronously, given an event type.
2600  */
sdev_evt_send_simple(struct scsi_device * sdev,enum scsi_device_event evt_type,gfp_t gfpflags)2601 void sdev_evt_send_simple(struct scsi_device *sdev,
2602 			  enum scsi_device_event evt_type, gfp_t gfpflags)
2603 {
2604 	struct scsi_event *evt = sdev_evt_alloc(evt_type, gfpflags);
2605 	if (!evt) {
2606 		sdev_printk(KERN_ERR, sdev, "event %d eaten due to OOM\n",
2607 			    evt_type);
2608 		return;
2609 	}
2610 
2611 	sdev_evt_send(sdev, evt);
2612 }
2613 EXPORT_SYMBOL_GPL(sdev_evt_send_simple);
2614 
2615 /**
2616  *	scsi_device_quiesce - Block all commands except power management.
2617  *	@sdev:	scsi device to quiesce.
2618  *
2619  *	This works by trying to transition to the SDEV_QUIESCE state
2620  *	(which must be a legal transition).  When the device is in this
2621  *	state, only power management requests will be accepted, all others will
2622  *	be deferred.
2623  *
2624  *	Must be called with user context, may sleep.
2625  *
2626  *	Returns zero if unsuccessful or an error if not.
2627  */
2628 int
scsi_device_quiesce(struct scsi_device * sdev)2629 scsi_device_quiesce(struct scsi_device *sdev)
2630 {
2631 	struct request_queue *q = sdev->request_queue;
2632 	int err;
2633 
2634 	/*
2635 	 * It is allowed to call scsi_device_quiesce() multiple times from
2636 	 * the same context but concurrent scsi_device_quiesce() calls are
2637 	 * not allowed.
2638 	 */
2639 	WARN_ON_ONCE(sdev->quiesced_by && sdev->quiesced_by != current);
2640 
2641 	if (sdev->quiesced_by == current)
2642 		return 0;
2643 
2644 	blk_set_pm_only(q);
2645 
2646 	blk_mq_freeze_queue(q);
2647 	/*
2648 	 * Ensure that the effect of blk_set_pm_only() will be visible
2649 	 * for percpu_ref_tryget() callers that occur after the queue
2650 	 * unfreeze even if the queue was already frozen before this function
2651 	 * was called. See also https://lwn.net/Articles/573497/.
2652 	 */
2653 	synchronize_rcu();
2654 	blk_mq_unfreeze_queue(q);
2655 
2656 	mutex_lock(&sdev->state_mutex);
2657 	err = scsi_device_set_state(sdev, SDEV_QUIESCE);
2658 	if (err == 0)
2659 		sdev->quiesced_by = current;
2660 	else
2661 		blk_clear_pm_only(q);
2662 	mutex_unlock(&sdev->state_mutex);
2663 
2664 	return err;
2665 }
2666 EXPORT_SYMBOL(scsi_device_quiesce);
2667 
2668 /**
2669  *	scsi_device_resume - Restart user issued commands to a quiesced device.
2670  *	@sdev:	scsi device to resume.
2671  *
2672  *	Moves the device from quiesced back to running and restarts the
2673  *	queues.
2674  *
2675  *	Must be called with user context, may sleep.
2676  */
scsi_device_resume(struct scsi_device * sdev)2677 void scsi_device_resume(struct scsi_device *sdev)
2678 {
2679 	/* check if the device state was mutated prior to resume, and if
2680 	 * so assume the state is being managed elsewhere (for example
2681 	 * device deleted during suspend)
2682 	 */
2683 	mutex_lock(&sdev->state_mutex);
2684 	if (sdev->sdev_state == SDEV_QUIESCE)
2685 		scsi_device_set_state(sdev, SDEV_RUNNING);
2686 	if (sdev->quiesced_by) {
2687 		sdev->quiesced_by = NULL;
2688 		blk_clear_pm_only(sdev->request_queue);
2689 	}
2690 	mutex_unlock(&sdev->state_mutex);
2691 }
2692 EXPORT_SYMBOL(scsi_device_resume);
2693 
2694 static void
device_quiesce_fn(struct scsi_device * sdev,void * data)2695 device_quiesce_fn(struct scsi_device *sdev, void *data)
2696 {
2697 	scsi_device_quiesce(sdev);
2698 }
2699 
2700 void
scsi_target_quiesce(struct scsi_target * starget)2701 scsi_target_quiesce(struct scsi_target *starget)
2702 {
2703 	starget_for_each_device(starget, NULL, device_quiesce_fn);
2704 }
2705 EXPORT_SYMBOL(scsi_target_quiesce);
2706 
2707 static void
device_resume_fn(struct scsi_device * sdev,void * data)2708 device_resume_fn(struct scsi_device *sdev, void *data)
2709 {
2710 	scsi_device_resume(sdev);
2711 }
2712 
2713 void
scsi_target_resume(struct scsi_target * starget)2714 scsi_target_resume(struct scsi_target *starget)
2715 {
2716 	starget_for_each_device(starget, NULL, device_resume_fn);
2717 }
2718 EXPORT_SYMBOL(scsi_target_resume);
2719 
__scsi_internal_device_block_nowait(struct scsi_device * sdev)2720 static int __scsi_internal_device_block_nowait(struct scsi_device *sdev)
2721 {
2722 	if (scsi_device_set_state(sdev, SDEV_BLOCK))
2723 		return scsi_device_set_state(sdev, SDEV_CREATED_BLOCK);
2724 
2725 	return 0;
2726 }
2727 
scsi_start_queue(struct scsi_device * sdev)2728 void scsi_start_queue(struct scsi_device *sdev)
2729 {
2730 	if (cmpxchg(&sdev->queue_stopped, 1, 0))
2731 		blk_mq_unquiesce_queue(sdev->request_queue);
2732 }
2733 
scsi_stop_queue(struct scsi_device * sdev)2734 static void scsi_stop_queue(struct scsi_device *sdev)
2735 {
2736 	/*
2737 	 * The atomic variable of ->queue_stopped covers that
2738 	 * blk_mq_quiesce_queue* is balanced with blk_mq_unquiesce_queue.
2739 	 *
2740 	 * The caller needs to wait until quiesce is done.
2741 	 */
2742 	if (!cmpxchg(&sdev->queue_stopped, 0, 1))
2743 		blk_mq_quiesce_queue_nowait(sdev->request_queue);
2744 }
2745 
2746 /**
2747  * scsi_internal_device_block_nowait - try to transition to the SDEV_BLOCK state
2748  * @sdev: device to block
2749  *
2750  * Pause SCSI command processing on the specified device. Does not sleep.
2751  *
2752  * Returns zero if successful or a negative error code upon failure.
2753  *
2754  * Notes:
2755  * This routine transitions the device to the SDEV_BLOCK state (which must be
2756  * a legal transition). When the device is in this state, command processing
2757  * is paused until the device leaves the SDEV_BLOCK state. See also
2758  * scsi_internal_device_unblock_nowait().
2759  */
scsi_internal_device_block_nowait(struct scsi_device * sdev)2760 int scsi_internal_device_block_nowait(struct scsi_device *sdev)
2761 {
2762 	int ret = __scsi_internal_device_block_nowait(sdev);
2763 
2764 	/*
2765 	 * The device has transitioned to SDEV_BLOCK.  Stop the
2766 	 * block layer from calling the midlayer with this device's
2767 	 * request queue.
2768 	 */
2769 	if (!ret)
2770 		scsi_stop_queue(sdev);
2771 	return ret;
2772 }
2773 EXPORT_SYMBOL_GPL(scsi_internal_device_block_nowait);
2774 
2775 /**
2776  * scsi_device_block - try to transition to the SDEV_BLOCK state
2777  * @sdev: device to block
2778  * @data: dummy argument, ignored
2779  *
2780  * Pause SCSI command processing on the specified device. Callers must wait
2781  * until all ongoing scsi_queue_rq() calls have finished after this function
2782  * returns.
2783  *
2784  * Note:
2785  * This routine transitions the device to the SDEV_BLOCK state (which must be
2786  * a legal transition). When the device is in this state, command processing
2787  * is paused until the device leaves the SDEV_BLOCK state. See also
2788  * scsi_internal_device_unblock().
2789  */
scsi_device_block(struct scsi_device * sdev,void * data)2790 static void scsi_device_block(struct scsi_device *sdev, void *data)
2791 {
2792 	int err;
2793 	enum scsi_device_state state;
2794 
2795 	mutex_lock(&sdev->state_mutex);
2796 	err = __scsi_internal_device_block_nowait(sdev);
2797 	state = sdev->sdev_state;
2798 	if (err == 0)
2799 		/*
2800 		 * scsi_stop_queue() must be called with the state_mutex
2801 		 * held. Otherwise a simultaneous scsi_start_queue() call
2802 		 * might unquiesce the queue before we quiesce it.
2803 		 */
2804 		scsi_stop_queue(sdev);
2805 
2806 	mutex_unlock(&sdev->state_mutex);
2807 
2808 	WARN_ONCE(err, "%s: failed to block %s in state %d\n",
2809 		  __func__, dev_name(&sdev->sdev_gendev), state);
2810 }
2811 
2812 /**
2813  * scsi_internal_device_unblock_nowait - resume a device after a block request
2814  * @sdev:	device to resume
2815  * @new_state:	state to set the device to after unblocking
2816  *
2817  * Restart the device queue for a previously suspended SCSI device. Does not
2818  * sleep.
2819  *
2820  * Returns zero if successful or a negative error code upon failure.
2821  *
2822  * Notes:
2823  * This routine transitions the device to the SDEV_RUNNING state or to one of
2824  * the offline states (which must be a legal transition) allowing the midlayer
2825  * to goose the queue for this device.
2826  */
scsi_internal_device_unblock_nowait(struct scsi_device * sdev,enum scsi_device_state new_state)2827 int scsi_internal_device_unblock_nowait(struct scsi_device *sdev,
2828 					enum scsi_device_state new_state)
2829 {
2830 	switch (new_state) {
2831 	case SDEV_RUNNING:
2832 	case SDEV_TRANSPORT_OFFLINE:
2833 		break;
2834 	default:
2835 		return -EINVAL;
2836 	}
2837 
2838 	/*
2839 	 * Try to transition the scsi device to SDEV_RUNNING or one of the
2840 	 * offlined states and goose the device queue if successful.
2841 	 */
2842 	switch (sdev->sdev_state) {
2843 	case SDEV_BLOCK:
2844 	case SDEV_TRANSPORT_OFFLINE:
2845 		sdev->sdev_state = new_state;
2846 		break;
2847 	case SDEV_CREATED_BLOCK:
2848 		if (new_state == SDEV_TRANSPORT_OFFLINE ||
2849 		    new_state == SDEV_OFFLINE)
2850 			sdev->sdev_state = new_state;
2851 		else
2852 			sdev->sdev_state = SDEV_CREATED;
2853 		break;
2854 	case SDEV_CANCEL:
2855 	case SDEV_OFFLINE:
2856 		break;
2857 	default:
2858 		return -EINVAL;
2859 	}
2860 	scsi_start_queue(sdev);
2861 
2862 	return 0;
2863 }
2864 EXPORT_SYMBOL_GPL(scsi_internal_device_unblock_nowait);
2865 
2866 /**
2867  * scsi_internal_device_unblock - resume a device after a block request
2868  * @sdev:	device to resume
2869  * @new_state:	state to set the device to after unblocking
2870  *
2871  * Restart the device queue for a previously suspended SCSI device. May sleep.
2872  *
2873  * Returns zero if successful or a negative error code upon failure.
2874  *
2875  * Notes:
2876  * This routine transitions the device to the SDEV_RUNNING state or to one of
2877  * the offline states (which must be a legal transition) allowing the midlayer
2878  * to goose the queue for this device.
2879  */
scsi_internal_device_unblock(struct scsi_device * sdev,enum scsi_device_state new_state)2880 static int scsi_internal_device_unblock(struct scsi_device *sdev,
2881 					enum scsi_device_state new_state)
2882 {
2883 	int ret;
2884 
2885 	mutex_lock(&sdev->state_mutex);
2886 	ret = scsi_internal_device_unblock_nowait(sdev, new_state);
2887 	mutex_unlock(&sdev->state_mutex);
2888 
2889 	return ret;
2890 }
2891 
2892 static int
target_block(struct device * dev,void * data)2893 target_block(struct device *dev, void *data)
2894 {
2895 	if (scsi_is_target_device(dev))
2896 		starget_for_each_device(to_scsi_target(dev), NULL,
2897 					scsi_device_block);
2898 	return 0;
2899 }
2900 
2901 /**
2902  * scsi_block_targets - transition all SCSI child devices to SDEV_BLOCK state
2903  * @dev: a parent device of one or more scsi_target devices
2904  * @shost: the Scsi_Host to which this device belongs
2905  *
2906  * Iterate over all children of @dev, which should be scsi_target devices,
2907  * and switch all subordinate scsi devices to SDEV_BLOCK state. Wait for
2908  * ongoing scsi_queue_rq() calls to finish. May sleep.
2909  *
2910  * Note:
2911  * @dev must not itself be a scsi_target device.
2912  */
2913 void
scsi_block_targets(struct Scsi_Host * shost,struct device * dev)2914 scsi_block_targets(struct Scsi_Host *shost, struct device *dev)
2915 {
2916 	WARN_ON_ONCE(scsi_is_target_device(dev));
2917 	device_for_each_child(dev, NULL, target_block);
2918 	blk_mq_wait_quiesce_done(&shost->tag_set);
2919 }
2920 EXPORT_SYMBOL_GPL(scsi_block_targets);
2921 
2922 static void
device_unblock(struct scsi_device * sdev,void * data)2923 device_unblock(struct scsi_device *sdev, void *data)
2924 {
2925 	scsi_internal_device_unblock(sdev, *(enum scsi_device_state *)data);
2926 }
2927 
2928 static int
target_unblock(struct device * dev,void * data)2929 target_unblock(struct device *dev, void *data)
2930 {
2931 	if (scsi_is_target_device(dev))
2932 		starget_for_each_device(to_scsi_target(dev), data,
2933 					device_unblock);
2934 	return 0;
2935 }
2936 
2937 void
scsi_target_unblock(struct device * dev,enum scsi_device_state new_state)2938 scsi_target_unblock(struct device *dev, enum scsi_device_state new_state)
2939 {
2940 	if (scsi_is_target_device(dev))
2941 		starget_for_each_device(to_scsi_target(dev), &new_state,
2942 					device_unblock);
2943 	else
2944 		device_for_each_child(dev, &new_state, target_unblock);
2945 }
2946 EXPORT_SYMBOL_GPL(scsi_target_unblock);
2947 
2948 /**
2949  * scsi_host_block - Try to transition all logical units to the SDEV_BLOCK state
2950  * @shost: device to block
2951  *
2952  * Pause SCSI command processing for all logical units associated with the SCSI
2953  * host and wait until pending scsi_queue_rq() calls have finished.
2954  *
2955  * Returns zero if successful or a negative error code upon failure.
2956  */
2957 int
scsi_host_block(struct Scsi_Host * shost)2958 scsi_host_block(struct Scsi_Host *shost)
2959 {
2960 	struct scsi_device *sdev;
2961 	int ret;
2962 
2963 	/*
2964 	 * Call scsi_internal_device_block_nowait so we can avoid
2965 	 * calling synchronize_rcu() for each LUN.
2966 	 */
2967 	shost_for_each_device(sdev, shost) {
2968 		mutex_lock(&sdev->state_mutex);
2969 		ret = scsi_internal_device_block_nowait(sdev);
2970 		mutex_unlock(&sdev->state_mutex);
2971 		if (ret) {
2972 			scsi_device_put(sdev);
2973 			return ret;
2974 		}
2975 	}
2976 
2977 	/* Wait for ongoing scsi_queue_rq() calls to finish. */
2978 	blk_mq_wait_quiesce_done(&shost->tag_set);
2979 
2980 	return 0;
2981 }
2982 EXPORT_SYMBOL_GPL(scsi_host_block);
2983 
2984 int
scsi_host_unblock(struct Scsi_Host * shost,int new_state)2985 scsi_host_unblock(struct Scsi_Host *shost, int new_state)
2986 {
2987 	struct scsi_device *sdev;
2988 	int ret = 0;
2989 
2990 	shost_for_each_device(sdev, shost) {
2991 		ret = scsi_internal_device_unblock(sdev, new_state);
2992 		if (ret) {
2993 			scsi_device_put(sdev);
2994 			break;
2995 		}
2996 	}
2997 	return ret;
2998 }
2999 EXPORT_SYMBOL_GPL(scsi_host_unblock);
3000 
3001 /**
3002  * scsi_kmap_atomic_sg - find and atomically map an sg-elemnt
3003  * @sgl:	scatter-gather list
3004  * @sg_count:	number of segments in sg
3005  * @offset:	offset in bytes into sg, on return offset into the mapped area
3006  * @len:	bytes to map, on return number of bytes mapped
3007  *
3008  * Returns virtual address of the start of the mapped page
3009  */
scsi_kmap_atomic_sg(struct scatterlist * sgl,int sg_count,size_t * offset,size_t * len)3010 void *scsi_kmap_atomic_sg(struct scatterlist *sgl, int sg_count,
3011 			  size_t *offset, size_t *len)
3012 {
3013 	int i;
3014 	size_t sg_len = 0, len_complete = 0;
3015 	struct scatterlist *sg;
3016 	struct page *page;
3017 
3018 	WARN_ON(!irqs_disabled());
3019 
3020 	for_each_sg(sgl, sg, sg_count, i) {
3021 		len_complete = sg_len; /* Complete sg-entries */
3022 		sg_len += sg->length;
3023 		if (sg_len > *offset)
3024 			break;
3025 	}
3026 
3027 	if (unlikely(i == sg_count)) {
3028 		printk(KERN_ERR "%s: Bytes in sg: %zu, requested offset %zu, "
3029 			"elements %d\n",
3030 		       __func__, sg_len, *offset, sg_count);
3031 		WARN_ON(1);
3032 		return NULL;
3033 	}
3034 
3035 	/* Offset starting from the beginning of first page in this sg-entry */
3036 	*offset = *offset - len_complete + sg->offset;
3037 
3038 	/* Assumption: contiguous pages can be accessed as "page + i" */
3039 	page = nth_page(sg_page(sg), (*offset >> PAGE_SHIFT));
3040 	*offset &= ~PAGE_MASK;
3041 
3042 	/* Bytes in this sg-entry from *offset to the end of the page */
3043 	sg_len = PAGE_SIZE - *offset;
3044 	if (*len > sg_len)
3045 		*len = sg_len;
3046 
3047 	return kmap_atomic(page);
3048 }
3049 EXPORT_SYMBOL(scsi_kmap_atomic_sg);
3050 
3051 /**
3052  * scsi_kunmap_atomic_sg - atomically unmap a virtual address, previously mapped with scsi_kmap_atomic_sg
3053  * @virt:	virtual address to be unmapped
3054  */
scsi_kunmap_atomic_sg(void * virt)3055 void scsi_kunmap_atomic_sg(void *virt)
3056 {
3057 	kunmap_atomic(virt);
3058 }
3059 EXPORT_SYMBOL(scsi_kunmap_atomic_sg);
3060 
sdev_disable_disk_events(struct scsi_device * sdev)3061 void sdev_disable_disk_events(struct scsi_device *sdev)
3062 {
3063 	atomic_inc(&sdev->disk_events_disable_depth);
3064 }
3065 EXPORT_SYMBOL(sdev_disable_disk_events);
3066 
sdev_enable_disk_events(struct scsi_device * sdev)3067 void sdev_enable_disk_events(struct scsi_device *sdev)
3068 {
3069 	if (WARN_ON_ONCE(atomic_read(&sdev->disk_events_disable_depth) <= 0))
3070 		return;
3071 	atomic_dec(&sdev->disk_events_disable_depth);
3072 }
3073 EXPORT_SYMBOL(sdev_enable_disk_events);
3074 
designator_prio(const unsigned char * d)3075 static unsigned char designator_prio(const unsigned char *d)
3076 {
3077 	if (d[1] & 0x30)
3078 		/* not associated with LUN */
3079 		return 0;
3080 
3081 	if (d[3] == 0)
3082 		/* invalid length */
3083 		return 0;
3084 
3085 	/*
3086 	 * Order of preference for lun descriptor:
3087 	 * - SCSI name string
3088 	 * - NAA IEEE Registered Extended
3089 	 * - EUI-64 based 16-byte
3090 	 * - EUI-64 based 12-byte
3091 	 * - NAA IEEE Registered
3092 	 * - NAA IEEE Extended
3093 	 * - EUI-64 based 8-byte
3094 	 * - SCSI name string (truncated)
3095 	 * - T10 Vendor ID
3096 	 * as longer descriptors reduce the likelyhood
3097 	 * of identification clashes.
3098 	 */
3099 
3100 	switch (d[1] & 0xf) {
3101 	case 8:
3102 		/* SCSI name string, variable-length UTF-8 */
3103 		return 9;
3104 	case 3:
3105 		switch (d[4] >> 4) {
3106 		case 6:
3107 			/* NAA registered extended */
3108 			return 8;
3109 		case 5:
3110 			/* NAA registered */
3111 			return 5;
3112 		case 4:
3113 			/* NAA extended */
3114 			return 4;
3115 		case 3:
3116 			/* NAA locally assigned */
3117 			return 1;
3118 		default:
3119 			break;
3120 		}
3121 		break;
3122 	case 2:
3123 		switch (d[3]) {
3124 		case 16:
3125 			/* EUI64-based, 16 byte */
3126 			return 7;
3127 		case 12:
3128 			/* EUI64-based, 12 byte */
3129 			return 6;
3130 		case 8:
3131 			/* EUI64-based, 8 byte */
3132 			return 3;
3133 		default:
3134 			break;
3135 		}
3136 		break;
3137 	case 1:
3138 		/* T10 vendor ID */
3139 		return 1;
3140 	default:
3141 		break;
3142 	}
3143 
3144 	return 0;
3145 }
3146 
3147 /**
3148  * scsi_vpd_lun_id - return a unique device identification
3149  * @sdev: SCSI device
3150  * @id:   buffer for the identification
3151  * @id_len:  length of the buffer
3152  *
3153  * Copies a unique device identification into @id based
3154  * on the information in the VPD page 0x83 of the device.
3155  * The string will be formatted as a SCSI name string.
3156  *
3157  * Returns the length of the identification or error on failure.
3158  * If the identifier is longer than the supplied buffer the actual
3159  * identifier length is returned and the buffer is not zero-padded.
3160  */
scsi_vpd_lun_id(struct scsi_device * sdev,char * id,size_t id_len)3161 int scsi_vpd_lun_id(struct scsi_device *sdev, char *id, size_t id_len)
3162 {
3163 	u8 cur_id_prio = 0;
3164 	u8 cur_id_size = 0;
3165 	const unsigned char *d, *cur_id_str;
3166 	const struct scsi_vpd *vpd_pg83;
3167 	int id_size = -EINVAL;
3168 
3169 	rcu_read_lock();
3170 	vpd_pg83 = rcu_dereference(sdev->vpd_pg83);
3171 	if (!vpd_pg83) {
3172 		rcu_read_unlock();
3173 		return -ENXIO;
3174 	}
3175 
3176 	/* The id string must be at least 20 bytes + terminating NULL byte */
3177 	if (id_len < 21) {
3178 		rcu_read_unlock();
3179 		return -EINVAL;
3180 	}
3181 
3182 	memset(id, 0, id_len);
3183 	for (d = vpd_pg83->data + 4;
3184 	     d < vpd_pg83->data + vpd_pg83->len;
3185 	     d += d[3] + 4) {
3186 		u8 prio = designator_prio(d);
3187 
3188 		if (prio == 0 || cur_id_prio > prio)
3189 			continue;
3190 
3191 		switch (d[1] & 0xf) {
3192 		case 0x1:
3193 			/* T10 Vendor ID */
3194 			if (cur_id_size > d[3])
3195 				break;
3196 			cur_id_prio = prio;
3197 			cur_id_size = d[3];
3198 			if (cur_id_size + 4 > id_len)
3199 				cur_id_size = id_len - 4;
3200 			cur_id_str = d + 4;
3201 			id_size = snprintf(id, id_len, "t10.%*pE",
3202 					   cur_id_size, cur_id_str);
3203 			break;
3204 		case 0x2:
3205 			/* EUI-64 */
3206 			cur_id_prio = prio;
3207 			cur_id_size = d[3];
3208 			cur_id_str = d + 4;
3209 			switch (cur_id_size) {
3210 			case 8:
3211 				id_size = snprintf(id, id_len,
3212 						   "eui.%8phN",
3213 						   cur_id_str);
3214 				break;
3215 			case 12:
3216 				id_size = snprintf(id, id_len,
3217 						   "eui.%12phN",
3218 						   cur_id_str);
3219 				break;
3220 			case 16:
3221 				id_size = snprintf(id, id_len,
3222 						   "eui.%16phN",
3223 						   cur_id_str);
3224 				break;
3225 			default:
3226 				break;
3227 			}
3228 			break;
3229 		case 0x3:
3230 			/* NAA */
3231 			cur_id_prio = prio;
3232 			cur_id_size = d[3];
3233 			cur_id_str = d + 4;
3234 			switch (cur_id_size) {
3235 			case 8:
3236 				id_size = snprintf(id, id_len,
3237 						   "naa.%8phN",
3238 						   cur_id_str);
3239 				break;
3240 			case 16:
3241 				id_size = snprintf(id, id_len,
3242 						   "naa.%16phN",
3243 						   cur_id_str);
3244 				break;
3245 			default:
3246 				break;
3247 			}
3248 			break;
3249 		case 0x8:
3250 			/* SCSI name string */
3251 			if (cur_id_size > d[3])
3252 				break;
3253 			/* Prefer others for truncated descriptor */
3254 			if (d[3] > id_len) {
3255 				prio = 2;
3256 				if (cur_id_prio > prio)
3257 					break;
3258 			}
3259 			cur_id_prio = prio;
3260 			cur_id_size = id_size = d[3];
3261 			cur_id_str = d + 4;
3262 			if (cur_id_size >= id_len)
3263 				cur_id_size = id_len - 1;
3264 			memcpy(id, cur_id_str, cur_id_size);
3265 			break;
3266 		default:
3267 			break;
3268 		}
3269 	}
3270 	rcu_read_unlock();
3271 
3272 	return id_size;
3273 }
3274 EXPORT_SYMBOL(scsi_vpd_lun_id);
3275 
3276 /*
3277  * scsi_vpd_tpg_id - return a target port group identifier
3278  * @sdev: SCSI device
3279  *
3280  * Returns the Target Port Group identifier from the information
3281  * froom VPD page 0x83 of the device.
3282  *
3283  * Returns the identifier or error on failure.
3284  */
scsi_vpd_tpg_id(struct scsi_device * sdev,int * rel_id)3285 int scsi_vpd_tpg_id(struct scsi_device *sdev, int *rel_id)
3286 {
3287 	const unsigned char *d;
3288 	const struct scsi_vpd *vpd_pg83;
3289 	int group_id = -EAGAIN, rel_port = -1;
3290 
3291 	rcu_read_lock();
3292 	vpd_pg83 = rcu_dereference(sdev->vpd_pg83);
3293 	if (!vpd_pg83) {
3294 		rcu_read_unlock();
3295 		return -ENXIO;
3296 	}
3297 
3298 	d = vpd_pg83->data + 4;
3299 	while (d < vpd_pg83->data + vpd_pg83->len) {
3300 		switch (d[1] & 0xf) {
3301 		case 0x4:
3302 			/* Relative target port */
3303 			rel_port = get_unaligned_be16(&d[6]);
3304 			break;
3305 		case 0x5:
3306 			/* Target port group */
3307 			group_id = get_unaligned_be16(&d[6]);
3308 			break;
3309 		default:
3310 			break;
3311 		}
3312 		d += d[3] + 4;
3313 	}
3314 	rcu_read_unlock();
3315 
3316 	if (group_id >= 0 && rel_id && rel_port != -1)
3317 		*rel_id = rel_port;
3318 
3319 	return group_id;
3320 }
3321 EXPORT_SYMBOL(scsi_vpd_tpg_id);
3322 
3323 /**
3324  * scsi_build_sense - build sense data for a command
3325  * @scmd:	scsi command for which the sense should be formatted
3326  * @desc:	Sense format (non-zero == descriptor format,
3327  *              0 == fixed format)
3328  * @key:	Sense key
3329  * @asc:	Additional sense code
3330  * @ascq:	Additional sense code qualifier
3331  *
3332  **/
scsi_build_sense(struct scsi_cmnd * scmd,int desc,u8 key,u8 asc,u8 ascq)3333 void scsi_build_sense(struct scsi_cmnd *scmd, int desc, u8 key, u8 asc, u8 ascq)
3334 {
3335 	scsi_build_sense_buffer(desc, scmd->sense_buffer, key, asc, ascq);
3336 	scmd->result = SAM_STAT_CHECK_CONDITION;
3337 }
3338 EXPORT_SYMBOL_GPL(scsi_build_sense);
3339