Line data Source code
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/ratelimit.h>
25 : #include <asm/unaligned.h>
26 :
27 : #include <scsi/scsi.h>
28 : #include <scsi/scsi_cmnd.h>
29 : #include <scsi/scsi_dbg.h>
30 : #include <scsi/scsi_device.h>
31 : #include <scsi/scsi_driver.h>
32 : #include <scsi/scsi_eh.h>
33 : #include <scsi/scsi_host.h>
34 : #include <scsi/scsi_transport.h> /* __scsi_init_queue() */
35 : #include <scsi/scsi_dh.h>
36 :
37 : #include <trace/events/scsi.h>
38 :
39 : #include "scsi_debugfs.h"
40 : #include "scsi_priv.h"
41 : #include "scsi_logging.h"
42 :
43 : /*
44 : * Size of integrity metadata is usually small, 1 inline sg should
45 : * cover normal cases.
46 : */
47 : #ifdef CONFIG_ARCH_NO_SG_CHAIN
48 : #define SCSI_INLINE_PROT_SG_CNT 0
49 : #define SCSI_INLINE_SG_CNT 0
50 : #else
51 : #define SCSI_INLINE_PROT_SG_CNT 1
52 : #define SCSI_INLINE_SG_CNT 2
53 : #endif
54 :
55 : static struct kmem_cache *scsi_sense_cache;
56 : static struct kmem_cache *scsi_sense_isadma_cache;
57 : static DEFINE_MUTEX(scsi_sense_cache_mutex);
58 :
59 : static void scsi_mq_uninit_cmd(struct scsi_cmnd *cmd);
60 :
61 : static inline struct kmem_cache *
62 0 : scsi_select_sense_cache(bool unchecked_isa_dma)
63 : {
64 0 : return unchecked_isa_dma ? scsi_sense_isadma_cache : scsi_sense_cache;
65 : }
66 :
67 0 : static void scsi_free_sense_buffer(bool unchecked_isa_dma,
68 : unsigned char *sense_buffer)
69 : {
70 0 : kmem_cache_free(scsi_select_sense_cache(unchecked_isa_dma),
71 : sense_buffer);
72 0 : }
73 :
74 0 : static unsigned char *scsi_alloc_sense_buffer(bool unchecked_isa_dma,
75 : gfp_t gfp_mask, int numa_node)
76 : {
77 0 : return kmem_cache_alloc_node(scsi_select_sense_cache(unchecked_isa_dma),
78 : gfp_mask, numa_node);
79 : }
80 :
81 0 : int scsi_init_sense_cache(struct Scsi_Host *shost)
82 : {
83 0 : struct kmem_cache *cache;
84 0 : int ret = 0;
85 :
86 0 : mutex_lock(&scsi_sense_cache_mutex);
87 0 : cache = scsi_select_sense_cache(shost->unchecked_isa_dma);
88 0 : if (cache)
89 0 : goto exit;
90 :
91 0 : if (shost->unchecked_isa_dma) {
92 0 : scsi_sense_isadma_cache =
93 0 : kmem_cache_create("scsi_sense_cache(DMA)",
94 : SCSI_SENSE_BUFFERSIZE, 0,
95 : SLAB_HWCACHE_ALIGN | SLAB_CACHE_DMA, NULL);
96 0 : if (!scsi_sense_isadma_cache)
97 0 : ret = -ENOMEM;
98 : } else {
99 0 : scsi_sense_cache =
100 0 : kmem_cache_create_usercopy("scsi_sense_cache",
101 : SCSI_SENSE_BUFFERSIZE, 0, SLAB_HWCACHE_ALIGN,
102 : 0, SCSI_SENSE_BUFFERSIZE, NULL);
103 0 : if (!scsi_sense_cache)
104 0 : ret = -ENOMEM;
105 : }
106 0 : exit:
107 0 : mutex_unlock(&scsi_sense_cache_mutex);
108 0 : return ret;
109 : }
110 :
111 : /*
112 : * When to reinvoke queueing after a resource shortage. It's 3 msecs to
113 : * not change behaviour from the previous unplug mechanism, experimentation
114 : * may prove this needs changing.
115 : */
116 : #define SCSI_QUEUE_DELAY 3
117 :
118 : static void
119 0 : scsi_set_blocked(struct scsi_cmnd *cmd, int reason)
120 : {
121 0 : struct Scsi_Host *host = cmd->device->host;
122 0 : struct scsi_device *device = cmd->device;
123 0 : struct scsi_target *starget = scsi_target(device);
124 :
125 : /*
126 : * Set the appropriate busy bit for the device/host.
127 : *
128 : * If the host/device isn't busy, assume that something actually
129 : * completed, and that we should be able to queue a command now.
130 : *
131 : * Note that the prior mid-layer assumption that any host could
132 : * always queue at least one command is now broken. The mid-layer
133 : * will implement a user specifiable stall (see
134 : * scsi_host.max_host_blocked and scsi_device.max_device_blocked)
135 : * if a command is requeued with no other commands outstanding
136 : * either for the device or for the host.
137 : */
138 0 : switch (reason) {
139 0 : case SCSI_MLQUEUE_HOST_BUSY:
140 0 : atomic_set(&host->host_blocked, host->max_host_blocked);
141 : break;
142 0 : case SCSI_MLQUEUE_DEVICE_BUSY:
143 : case SCSI_MLQUEUE_EH_RETRY:
144 0 : atomic_set(&device->device_blocked,
145 0 : device->max_device_blocked);
146 : break;
147 0 : case SCSI_MLQUEUE_TARGET_BUSY:
148 0 : atomic_set(&starget->target_blocked,
149 0 : starget->max_target_blocked);
150 : break;
151 : }
152 0 : }
153 :
154 0 : static void scsi_mq_requeue_cmd(struct scsi_cmnd *cmd)
155 : {
156 0 : if (cmd->request->rq_flags & RQF_DONTPREP) {
157 0 : cmd->request->rq_flags &= ~RQF_DONTPREP;
158 0 : scsi_mq_uninit_cmd(cmd);
159 : } else {
160 0 : WARN_ON_ONCE(true);
161 : }
162 0 : blk_mq_requeue_request(cmd->request, true);
163 0 : }
164 :
165 : /**
166 : * __scsi_queue_insert - private queue insertion
167 : * @cmd: The SCSI command being requeued
168 : * @reason: The reason for the requeue
169 : * @unbusy: Whether the queue should be unbusied
170 : *
171 : * This is a private queue insertion. The public interface
172 : * scsi_queue_insert() always assumes the queue should be unbusied
173 : * because it's always called before the completion. This function is
174 : * for a requeue after completion, which should only occur in this
175 : * file.
176 : */
177 0 : static void __scsi_queue_insert(struct scsi_cmnd *cmd, int reason, bool unbusy)
178 : {
179 0 : struct scsi_device *device = cmd->device;
180 :
181 0 : SCSI_LOG_MLQUEUE(1, scmd_printk(KERN_INFO, cmd,
182 0 : "Inserting command %p into mlqueue\n", cmd));
183 :
184 0 : scsi_set_blocked(cmd, reason);
185 :
186 : /*
187 : * Decrement the counters, since these commands are no longer
188 : * active on the host/device.
189 : */
190 0 : if (unbusy)
191 0 : scsi_device_unbusy(device, cmd);
192 :
193 : /*
194 : * Requeue this command. It will go before all other commands
195 : * that are already in the queue. Schedule requeue work under
196 : * lock such that the kblockd_schedule_work() call happens
197 : * before blk_cleanup_queue() finishes.
198 : */
199 0 : cmd->result = 0;
200 :
201 0 : blk_mq_requeue_request(cmd->request, true);
202 0 : }
203 :
204 : /**
205 : * scsi_queue_insert - Reinsert a command in the queue.
206 : * @cmd: command that we are adding to queue.
207 : * @reason: why we are inserting command to queue.
208 : *
209 : * We do this for one of two cases. Either the host is busy and it cannot accept
210 : * any more commands for the time being, or the device returned QUEUE_FULL and
211 : * can accept no more commands.
212 : *
213 : * Context: This could be called either from an interrupt context or a normal
214 : * process context.
215 : */
216 0 : void scsi_queue_insert(struct scsi_cmnd *cmd, int reason)
217 : {
218 0 : __scsi_queue_insert(cmd, reason, true);
219 0 : }
220 :
221 :
222 : /**
223 : * __scsi_execute - insert request and wait for the result
224 : * @sdev: scsi device
225 : * @cmd: scsi command
226 : * @data_direction: data direction
227 : * @buffer: data buffer
228 : * @bufflen: len of buffer
229 : * @sense: optional sense buffer
230 : * @sshdr: optional decoded sense header
231 : * @timeout: request timeout in seconds
232 : * @retries: number of times to retry request
233 : * @flags: flags for ->cmd_flags
234 : * @rq_flags: flags for ->rq_flags
235 : * @resid: optional residual length
236 : *
237 : * Returns the scsi_cmnd result field if a command was executed, or a negative
238 : * Linux error code if we didn't get that far.
239 : */
240 0 : int __scsi_execute(struct scsi_device *sdev, const unsigned char *cmd,
241 : int data_direction, void *buffer, unsigned bufflen,
242 : unsigned char *sense, struct scsi_sense_hdr *sshdr,
243 : int timeout, int retries, u64 flags, req_flags_t rq_flags,
244 : int *resid)
245 : {
246 0 : struct request *req;
247 0 : struct scsi_request *rq;
248 0 : int ret = DRIVER_ERROR << 24;
249 :
250 0 : req = blk_get_request(sdev->request_queue,
251 : data_direction == DMA_TO_DEVICE ?
252 : REQ_OP_SCSI_OUT : REQ_OP_SCSI_IN,
253 0 : rq_flags & RQF_PM ? BLK_MQ_REQ_PM : 0);
254 0 : if (IS_ERR(req))
255 : return ret;
256 0 : rq = scsi_req(req);
257 :
258 0 : if (bufflen && blk_rq_map_kern(sdev->request_queue, req,
259 : buffer, bufflen, GFP_NOIO))
260 0 : goto out;
261 :
262 0 : rq->cmd_len = COMMAND_SIZE(cmd[0]);
263 0 : memcpy(rq->cmd, cmd, rq->cmd_len);
264 0 : rq->retries = retries;
265 0 : req->timeout = timeout;
266 0 : req->cmd_flags |= flags;
267 0 : req->rq_flags |= rq_flags | RQF_QUIET;
268 :
269 : /*
270 : * head injection *required* here otherwise quiesce won't work
271 : */
272 0 : blk_execute_rq(NULL, req, 1);
273 :
274 : /*
275 : * Some devices (USB mass-storage in particular) may transfer
276 : * garbage data together with a residue indicating that the data
277 : * is invalid. Prevent the garbage from being misinterpreted
278 : * and prevent security leaks by zeroing out the excess data.
279 : */
280 0 : if (unlikely(rq->resid_len > 0 && rq->resid_len <= bufflen))
281 0 : memset(buffer + (bufflen - rq->resid_len), 0, rq->resid_len);
282 :
283 0 : if (resid)
284 0 : *resid = rq->resid_len;
285 0 : if (sense && rq->sense_len)
286 0 : memcpy(sense, rq->sense, SCSI_SENSE_BUFFERSIZE);
287 0 : if (sshdr)
288 0 : scsi_normalize_sense(rq->sense, rq->sense_len, sshdr);
289 0 : ret = rq->result;
290 0 : out:
291 0 : blk_put_request(req);
292 :
293 0 : return ret;
294 : }
295 : EXPORT_SYMBOL(__scsi_execute);
296 :
297 : /*
298 : * Wake up the error handler if necessary. Avoid as follows that the error
299 : * handler is not woken up if host in-flight requests number ==
300 : * shost->host_failed: use call_rcu() in scsi_eh_scmd_add() in combination
301 : * with an RCU read lock in this function to ensure that this function in
302 : * its entirety either finishes before scsi_eh_scmd_add() increases the
303 : * host_failed counter or that it notices the shost state change made by
304 : * scsi_eh_scmd_add().
305 : */
306 0 : static void scsi_dec_host_busy(struct Scsi_Host *shost, struct scsi_cmnd *cmd)
307 : {
308 0 : unsigned long flags;
309 :
310 0 : rcu_read_lock();
311 0 : __clear_bit(SCMD_STATE_INFLIGHT, &cmd->state);
312 0 : if (unlikely(scsi_host_in_recovery(shost))) {
313 0 : spin_lock_irqsave(shost->host_lock, flags);
314 0 : if (shost->host_failed || shost->host_eh_scheduled)
315 0 : scsi_eh_wakeup(shost);
316 0 : spin_unlock_irqrestore(shost->host_lock, flags);
317 : }
318 0 : rcu_read_unlock();
319 0 : }
320 :
321 0 : void scsi_device_unbusy(struct scsi_device *sdev, struct scsi_cmnd *cmd)
322 : {
323 0 : struct Scsi_Host *shost = sdev->host;
324 0 : struct scsi_target *starget = scsi_target(sdev);
325 :
326 0 : scsi_dec_host_busy(shost, cmd);
327 :
328 0 : if (starget->can_queue > 0)
329 0 : atomic_dec(&starget->target_busy);
330 :
331 0 : atomic_dec(&sdev->device_busy);
332 0 : }
333 :
334 0 : static void scsi_kick_queue(struct request_queue *q)
335 : {
336 0 : blk_mq_run_hw_queues(q, false);
337 : }
338 :
339 : /*
340 : * Called for single_lun devices on IO completion. Clear starget_sdev_user,
341 : * and call blk_run_queue for all the scsi_devices on the target -
342 : * including current_sdev first.
343 : *
344 : * Called with *no* scsi locks held.
345 : */
346 0 : static void scsi_single_lun_run(struct scsi_device *current_sdev)
347 : {
348 0 : struct Scsi_Host *shost = current_sdev->host;
349 0 : struct scsi_device *sdev, *tmp;
350 0 : struct scsi_target *starget = scsi_target(current_sdev);
351 0 : unsigned long flags;
352 :
353 0 : spin_lock_irqsave(shost->host_lock, flags);
354 0 : starget->starget_sdev_user = NULL;
355 0 : spin_unlock_irqrestore(shost->host_lock, flags);
356 :
357 : /*
358 : * Call blk_run_queue for all LUNs on the target, starting with
359 : * current_sdev. We race with others (to set starget_sdev_user),
360 : * but in most cases, we will be first. Ideally, each LU on the
361 : * target would get some limited time or requests on the target.
362 : */
363 0 : scsi_kick_queue(current_sdev->request_queue);
364 :
365 0 : spin_lock_irqsave(shost->host_lock, flags);
366 0 : if (starget->starget_sdev_user)
367 0 : goto out;
368 0 : list_for_each_entry_safe(sdev, tmp, &starget->devices,
369 : same_target_siblings) {
370 0 : if (sdev == current_sdev)
371 0 : continue;
372 0 : if (scsi_device_get(sdev))
373 0 : continue;
374 :
375 0 : spin_unlock_irqrestore(shost->host_lock, flags);
376 0 : scsi_kick_queue(sdev->request_queue);
377 0 : spin_lock_irqsave(shost->host_lock, flags);
378 :
379 0 : scsi_device_put(sdev);
380 : }
381 0 : out:
382 0 : spin_unlock_irqrestore(shost->host_lock, flags);
383 0 : }
384 :
385 0 : static inline bool scsi_device_is_busy(struct scsi_device *sdev)
386 : {
387 0 : if (atomic_read(&sdev->device_busy) >= sdev->queue_depth)
388 : return true;
389 0 : if (atomic_read(&sdev->device_blocked) > 0)
390 0 : return true;
391 : return false;
392 : }
393 :
394 0 : static inline bool scsi_target_is_busy(struct scsi_target *starget)
395 : {
396 0 : if (starget->can_queue > 0) {
397 0 : if (atomic_read(&starget->target_busy) >= starget->can_queue)
398 : return true;
399 0 : if (atomic_read(&starget->target_blocked) > 0)
400 0 : return true;
401 : }
402 : return false;
403 : }
404 :
405 0 : static inline bool scsi_host_is_busy(struct Scsi_Host *shost)
406 : {
407 0 : if (atomic_read(&shost->host_blocked) > 0)
408 : return true;
409 0 : if (shost->host_self_blocked)
410 0 : return true;
411 : return false;
412 : }
413 :
414 0 : static void scsi_starved_list_run(struct Scsi_Host *shost)
415 : {
416 0 : LIST_HEAD(starved_list);
417 0 : struct scsi_device *sdev;
418 0 : unsigned long flags;
419 :
420 0 : spin_lock_irqsave(shost->host_lock, flags);
421 0 : list_splice_init(&shost->starved_list, &starved_list);
422 :
423 0 : while (!list_empty(&starved_list)) {
424 0 : struct request_queue *slq;
425 :
426 : /*
427 : * As long as shost is accepting commands and we have
428 : * starved queues, call blk_run_queue. scsi_request_fn
429 : * drops the queue_lock and can add us back to the
430 : * starved_list.
431 : *
432 : * host_lock protects the starved_list and starved_entry.
433 : * scsi_request_fn must get the host_lock before checking
434 : * or modifying starved_list or starved_entry.
435 : */
436 0 : if (scsi_host_is_busy(shost))
437 : break;
438 :
439 0 : sdev = list_entry(starved_list.next,
440 : struct scsi_device, starved_entry);
441 0 : list_del_init(&sdev->starved_entry);
442 0 : if (scsi_target_is_busy(scsi_target(sdev))) {
443 0 : list_move_tail(&sdev->starved_entry,
444 : &shost->starved_list);
445 0 : continue;
446 : }
447 :
448 : /*
449 : * Once we drop the host lock, a racing scsi_remove_device()
450 : * call may remove the sdev from the starved list and destroy
451 : * it and the queue. Mitigate by taking a reference to the
452 : * queue and never touching the sdev again after we drop the
453 : * host lock. Note: if __scsi_remove_device() invokes
454 : * blk_cleanup_queue() before the queue is run from this
455 : * function then blk_run_queue() will return immediately since
456 : * blk_cleanup_queue() marks the queue with QUEUE_FLAG_DYING.
457 : */
458 0 : slq = sdev->request_queue;
459 0 : if (!blk_get_queue(slq))
460 0 : continue;
461 0 : spin_unlock_irqrestore(shost->host_lock, flags);
462 :
463 0 : scsi_kick_queue(slq);
464 0 : blk_put_queue(slq);
465 :
466 0 : spin_lock_irqsave(shost->host_lock, flags);
467 : }
468 : /* put any unprocessed entries back */
469 0 : list_splice(&starved_list, &shost->starved_list);
470 0 : spin_unlock_irqrestore(shost->host_lock, flags);
471 0 : }
472 :
473 : /**
474 : * scsi_run_queue - Select a proper request queue to serve next.
475 : * @q: last request's queue
476 : *
477 : * The previous command was completely finished, start a new one if possible.
478 : */
479 0 : static void scsi_run_queue(struct request_queue *q)
480 : {
481 0 : struct scsi_device *sdev = q->queuedata;
482 :
483 0 : if (scsi_target(sdev)->single_lun)
484 0 : scsi_single_lun_run(sdev);
485 0 : if (!list_empty(&sdev->host->starved_list))
486 0 : scsi_starved_list_run(sdev->host);
487 :
488 0 : blk_mq_run_hw_queues(q, false);
489 0 : }
490 :
491 0 : void scsi_requeue_run_queue(struct work_struct *work)
492 : {
493 0 : struct scsi_device *sdev;
494 0 : struct request_queue *q;
495 :
496 0 : sdev = container_of(work, struct scsi_device, requeue_work);
497 0 : q = sdev->request_queue;
498 0 : scsi_run_queue(q);
499 0 : }
500 :
501 0 : void scsi_run_host_queues(struct Scsi_Host *shost)
502 : {
503 0 : struct scsi_device *sdev;
504 :
505 0 : shost_for_each_device(sdev, shost)
506 0 : scsi_run_queue(sdev->request_queue);
507 0 : }
508 :
509 0 : static void scsi_uninit_cmd(struct scsi_cmnd *cmd)
510 : {
511 0 : if (!blk_rq_is_passthrough(cmd->request)) {
512 0 : struct scsi_driver *drv = scsi_cmd_to_driver(cmd);
513 :
514 0 : if (drv->uninit_command)
515 0 : drv->uninit_command(cmd);
516 : }
517 0 : }
518 :
519 0 : void scsi_free_sgtables(struct scsi_cmnd *cmd)
520 : {
521 0 : if (cmd->sdb.table.nents)
522 0 : sg_free_table_chained(&cmd->sdb.table,
523 : SCSI_INLINE_SG_CNT);
524 0 : if (scsi_prot_sg_count(cmd))
525 0 : sg_free_table_chained(&cmd->prot_sdb->table,
526 : SCSI_INLINE_PROT_SG_CNT);
527 0 : }
528 : EXPORT_SYMBOL_GPL(scsi_free_sgtables);
529 :
530 0 : static void scsi_mq_uninit_cmd(struct scsi_cmnd *cmd)
531 : {
532 0 : scsi_free_sgtables(cmd);
533 0 : scsi_uninit_cmd(cmd);
534 0 : }
535 :
536 0 : static void scsi_run_queue_async(struct scsi_device *sdev)
537 : {
538 0 : if (scsi_target(sdev)->single_lun ||
539 0 : !list_empty(&sdev->host->starved_list)) {
540 0 : kblockd_schedule_work(&sdev->requeue_work);
541 : } else {
542 : /*
543 : * smp_mb() present in sbitmap_queue_clear() or implied in
544 : * .end_io is for ordering writing .device_busy in
545 : * scsi_device_unbusy() and reading sdev->restarts.
546 : */
547 0 : int old = atomic_read(&sdev->restarts);
548 :
549 : /*
550 : * ->restarts has to be kept as non-zero if new budget
551 : * contention occurs.
552 : *
553 : * No need to run queue when either another re-run
554 : * queue wins in updating ->restarts or a new budget
555 : * contention occurs.
556 : */
557 0 : if (old && atomic_cmpxchg(&sdev->restarts, old, 0) == old)
558 0 : blk_mq_run_hw_queues(sdev->request_queue, true);
559 : }
560 0 : }
561 :
562 : /* Returns false when no more bytes to process, true if there are more */
563 0 : static bool scsi_end_request(struct request *req, blk_status_t error,
564 : unsigned int bytes)
565 : {
566 0 : struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req);
567 0 : struct scsi_device *sdev = cmd->device;
568 0 : struct request_queue *q = sdev->request_queue;
569 :
570 0 : if (blk_update_request(req, error, bytes))
571 : return true;
572 :
573 0 : if (blk_queue_add_random(q))
574 0 : add_disk_randomness(req->rq_disk);
575 :
576 0 : if (!blk_rq_is_scsi(req)) {
577 0 : WARN_ON_ONCE(!(cmd->flags & SCMD_INITIALIZED));
578 0 : cmd->flags &= ~SCMD_INITIALIZED;
579 : }
580 :
581 : /*
582 : * Calling rcu_barrier() is not necessary here because the
583 : * SCSI error handler guarantees that the function called by
584 : * call_rcu() has been called before scsi_end_request() is
585 : * called.
586 : */
587 0 : destroy_rcu_head(&cmd->rcu);
588 :
589 : /*
590 : * In the MQ case the command gets freed by __blk_mq_end_request,
591 : * so we have to do all cleanup that depends on it earlier.
592 : *
593 : * We also can't kick the queues from irq context, so we
594 : * will have to defer it to a workqueue.
595 : */
596 0 : scsi_mq_uninit_cmd(cmd);
597 :
598 : /*
599 : * queue is still alive, so grab the ref for preventing it
600 : * from being cleaned up during running queue.
601 : */
602 0 : percpu_ref_get(&q->q_usage_counter);
603 :
604 0 : __blk_mq_end_request(req, error);
605 :
606 0 : scsi_run_queue_async(sdev);
607 :
608 0 : percpu_ref_put(&q->q_usage_counter);
609 0 : return false;
610 : }
611 :
612 : /**
613 : * scsi_result_to_blk_status - translate a SCSI result code into blk_status_t
614 : * @cmd: SCSI command
615 : * @result: scsi error code
616 : *
617 : * Translate a SCSI result code into a blk_status_t value. May reset the host
618 : * byte of @cmd->result.
619 : */
620 0 : static blk_status_t scsi_result_to_blk_status(struct scsi_cmnd *cmd, int result)
621 : {
622 0 : switch (host_byte(result)) {
623 0 : case DID_OK:
624 : /*
625 : * Also check the other bytes than the status byte in result
626 : * to handle the case when a SCSI LLD sets result to
627 : * DRIVER_SENSE << 24 without setting SAM_STAT_CHECK_CONDITION.
628 : */
629 0 : if (scsi_status_is_good(result) && (result & ~0xff) == 0)
630 0 : return BLK_STS_OK;
631 : return BLK_STS_IOERR;
632 : case DID_TRANSPORT_FAILFAST:
633 : case DID_TRANSPORT_MARGINAL:
634 : return BLK_STS_TRANSPORT;
635 : case DID_TARGET_FAILURE:
636 0 : set_host_byte(cmd, DID_OK);
637 0 : return BLK_STS_TARGET;
638 : case DID_NEXUS_FAILURE:
639 0 : set_host_byte(cmd, DID_OK);
640 0 : return BLK_STS_NEXUS;
641 : case DID_ALLOC_FAILURE:
642 0 : set_host_byte(cmd, DID_OK);
643 0 : return BLK_STS_NOSPC;
644 : case DID_MEDIUM_ERROR:
645 0 : set_host_byte(cmd, DID_OK);
646 0 : return BLK_STS_MEDIUM;
647 0 : default:
648 0 : return BLK_STS_IOERR;
649 : }
650 : }
651 :
652 : /* Helper for scsi_io_completion() when "reprep" action required. */
653 0 : static void scsi_io_completion_reprep(struct scsi_cmnd *cmd,
654 : struct request_queue *q)
655 : {
656 : /* A new command will be prepared and issued. */
657 0 : scsi_mq_requeue_cmd(cmd);
658 0 : }
659 :
660 0 : static bool scsi_cmd_runtime_exceeced(struct scsi_cmnd *cmd)
661 : {
662 0 : struct request *req = cmd->request;
663 0 : unsigned long wait_for;
664 :
665 0 : if (cmd->allowed == SCSI_CMD_RETRIES_NO_LIMIT)
666 : return false;
667 :
668 0 : wait_for = (cmd->allowed + 1) * req->timeout;
669 0 : if (time_before(cmd->jiffies_at_alloc + wait_for, jiffies)) {
670 0 : scmd_printk(KERN_ERR, cmd, "timing out command, waited %lus\n",
671 : wait_for/HZ);
672 0 : return true;
673 : }
674 : return false;
675 : }
676 :
677 : /* Helper for scsi_io_completion() when special action required. */
678 0 : static void scsi_io_completion_action(struct scsi_cmnd *cmd, int result)
679 : {
680 0 : struct request_queue *q = cmd->device->request_queue;
681 0 : struct request *req = cmd->request;
682 0 : int level = 0;
683 0 : enum {ACTION_FAIL, ACTION_REPREP, ACTION_RETRY,
684 : ACTION_DELAYED_RETRY} action;
685 0 : struct scsi_sense_hdr sshdr;
686 0 : bool sense_valid;
687 0 : bool sense_current = true; /* false implies "deferred sense" */
688 0 : blk_status_t blk_stat;
689 :
690 0 : sense_valid = scsi_command_normalize_sense(cmd, &sshdr);
691 0 : if (sense_valid)
692 0 : sense_current = !scsi_sense_is_deferred(&sshdr);
693 :
694 0 : blk_stat = scsi_result_to_blk_status(cmd, result);
695 :
696 0 : if (host_byte(result) == DID_RESET) {
697 : /* Third party bus reset or reset for error recovery
698 : * reasons. Just retry the command and see what
699 : * happens.
700 : */
701 : action = ACTION_RETRY;
702 0 : } else if (sense_valid && sense_current) {
703 0 : switch (sshdr.sense_key) {
704 0 : case UNIT_ATTENTION:
705 0 : if (cmd->device->removable) {
706 : /* Detected disc change. Set a bit
707 : * and quietly refuse further access.
708 : */
709 0 : cmd->device->changed = 1;
710 0 : action = ACTION_FAIL;
711 : } else {
712 : /* Must have been a power glitch, or a
713 : * bus reset. Could not have been a
714 : * media change, so we just retry the
715 : * command and see what happens.
716 : */
717 : action = ACTION_RETRY;
718 : }
719 : break;
720 0 : case ILLEGAL_REQUEST:
721 : /* If we had an ILLEGAL REQUEST returned, then
722 : * we may have performed an unsupported
723 : * command. The only thing this should be
724 : * would be a ten byte read where only a six
725 : * byte read was supported. Also, on a system
726 : * where READ CAPACITY failed, we may have
727 : * read past the end of the disk.
728 : */
729 0 : if ((cmd->device->use_10_for_rw &&
730 0 : sshdr.asc == 0x20 && sshdr.ascq == 0x00) &&
731 0 : (cmd->cmnd[0] == READ_10 ||
732 : cmd->cmnd[0] == WRITE_10)) {
733 : /* This will issue a new 6-byte command. */
734 0 : cmd->device->use_10_for_rw = 0;
735 0 : action = ACTION_REPREP;
736 0 : } else if (sshdr.asc == 0x10) /* DIX */ {
737 : action = ACTION_FAIL;
738 : blk_stat = BLK_STS_PROTECTION;
739 : /* INVALID COMMAND OPCODE or INVALID FIELD IN CDB */
740 0 : } else if (sshdr.asc == 0x20 || sshdr.asc == 0x24) {
741 : action = ACTION_FAIL;
742 : blk_stat = BLK_STS_TARGET;
743 : } else
744 : action = ACTION_FAIL;
745 : break;
746 0 : case ABORTED_COMMAND:
747 0 : action = ACTION_FAIL;
748 0 : if (sshdr.asc == 0x10) /* DIF */
749 : blk_stat = BLK_STS_PROTECTION;
750 : break;
751 0 : case NOT_READY:
752 : /* If the device is in the process of becoming
753 : * ready, or has a temporary blockage, retry.
754 : */
755 0 : if (sshdr.asc == 0x04) {
756 0 : switch (sshdr.ascq) {
757 : case 0x01: /* becoming ready */
758 : case 0x04: /* format in progress */
759 : case 0x05: /* rebuild in progress */
760 : case 0x06: /* recalculation in progress */
761 : case 0x07: /* operation in progress */
762 : case 0x08: /* Long write in progress */
763 : case 0x09: /* self test in progress */
764 : case 0x14: /* space allocation in progress */
765 : case 0x1a: /* start stop unit in progress */
766 : case 0x1b: /* sanitize in progress */
767 : case 0x1d: /* configuration in progress */
768 : case 0x24: /* depopulation in progress */
769 : action = ACTION_DELAYED_RETRY;
770 : break;
771 0 : case 0x0a: /* ALUA state transition */
772 0 : blk_stat = BLK_STS_AGAIN;
773 : fallthrough;
774 : default:
775 : action = ACTION_FAIL;
776 : break;
777 : }
778 : } else
779 : action = ACTION_FAIL;
780 : break;
781 : case VOLUME_OVERFLOW:
782 : /* See SSC3rXX or current. */
783 : action = ACTION_FAIL;
784 : break;
785 0 : case DATA_PROTECT:
786 0 : action = ACTION_FAIL;
787 0 : if ((sshdr.asc == 0x0C && sshdr.ascq == 0x12) ||
788 0 : (sshdr.asc == 0x55 &&
789 0 : (sshdr.ascq == 0x0E || sshdr.ascq == 0x0F))) {
790 : /* Insufficient zone resources */
791 : blk_stat = BLK_STS_ZONE_OPEN_RESOURCE;
792 : }
793 : break;
794 : default:
795 : action = ACTION_FAIL;
796 : break;
797 : }
798 : } else
799 : action = ACTION_FAIL;
800 :
801 0 : if (action != ACTION_FAIL && scsi_cmd_runtime_exceeced(cmd))
802 : action = ACTION_FAIL;
803 :
804 0 : switch (action) {
805 0 : case ACTION_FAIL:
806 : /* Give up and fail the remainder of the request */
807 0 : if (!(req->rq_flags & RQF_QUIET)) {
808 0 : static DEFINE_RATELIMIT_STATE(_rs,
809 : DEFAULT_RATELIMIT_INTERVAL,
810 : DEFAULT_RATELIMIT_BURST);
811 :
812 0 : if (unlikely(scsi_logging_level))
813 : level =
814 : SCSI_LOG_LEVEL(SCSI_LOG_MLCOMPLETE_SHIFT,
815 : SCSI_LOG_MLCOMPLETE_BITS);
816 :
817 : /*
818 : * if logging is enabled the failure will be printed
819 : * in scsi_log_completion(), so avoid duplicate messages
820 : */
821 0 : if (!level && __ratelimit(&_rs)) {
822 0 : scsi_print_result(cmd, NULL, FAILED);
823 0 : if (driver_byte(result) == DRIVER_SENSE)
824 0 : scsi_print_sense(cmd);
825 0 : scsi_print_command(cmd);
826 : }
827 : }
828 0 : if (!scsi_end_request(req, blk_stat, blk_rq_err_bytes(req)))
829 0 : return;
830 0 : fallthrough;
831 : case ACTION_REPREP:
832 0 : scsi_io_completion_reprep(cmd, q);
833 : break;
834 0 : case ACTION_RETRY:
835 : /* Retry the same command immediately */
836 0 : __scsi_queue_insert(cmd, SCSI_MLQUEUE_EH_RETRY, false);
837 0 : break;
838 0 : case ACTION_DELAYED_RETRY:
839 : /* Retry the same command after a delay */
840 0 : __scsi_queue_insert(cmd, SCSI_MLQUEUE_DEVICE_BUSY, false);
841 0 : break;
842 : }
843 0 : }
844 :
845 : /*
846 : * Helper for scsi_io_completion() when cmd->result is non-zero. Returns a
847 : * new result that may suppress further error checking. Also modifies
848 : * *blk_statp in some cases.
849 : */
850 0 : static int scsi_io_completion_nz_result(struct scsi_cmnd *cmd, int result,
851 : blk_status_t *blk_statp)
852 : {
853 0 : bool sense_valid;
854 0 : bool sense_current = true; /* false implies "deferred sense" */
855 0 : struct request *req = cmd->request;
856 0 : struct scsi_sense_hdr sshdr;
857 :
858 0 : sense_valid = scsi_command_normalize_sense(cmd, &sshdr);
859 0 : if (sense_valid)
860 0 : sense_current = !scsi_sense_is_deferred(&sshdr);
861 :
862 0 : if (blk_rq_is_passthrough(req)) {
863 0 : if (sense_valid) {
864 : /*
865 : * SG_IO wants current and deferred errors
866 : */
867 0 : scsi_req(req)->sense_len =
868 0 : min(8 + cmd->sense_buffer[7],
869 : SCSI_SENSE_BUFFERSIZE);
870 : }
871 0 : if (sense_current)
872 0 : *blk_statp = scsi_result_to_blk_status(cmd, result);
873 0 : } else if (blk_rq_bytes(req) == 0 && sense_current) {
874 : /*
875 : * Flush commands do not transfers any data, and thus cannot use
876 : * good_bytes != blk_rq_bytes(req) as the signal for an error.
877 : * This sets *blk_statp explicitly for the problem case.
878 : */
879 0 : *blk_statp = scsi_result_to_blk_status(cmd, result);
880 : }
881 : /*
882 : * Recovered errors need reporting, but they're always treated as
883 : * success, so fiddle the result code here. For passthrough requests
884 : * we already took a copy of the original into sreq->result which
885 : * is what gets returned to the user
886 : */
887 0 : if (sense_valid && (sshdr.sense_key == RECOVERED_ERROR)) {
888 0 : bool do_print = true;
889 : /*
890 : * if ATA PASS-THROUGH INFORMATION AVAILABLE [0x0, 0x1d]
891 : * skip print since caller wants ATA registers. Only occurs
892 : * on SCSI ATA PASS_THROUGH commands when CK_COND=1
893 : */
894 0 : if ((sshdr.asc == 0x0) && (sshdr.ascq == 0x1d))
895 : do_print = false;
896 0 : else if (req->rq_flags & RQF_QUIET)
897 : do_print = false;
898 0 : if (do_print)
899 0 : scsi_print_sense(cmd);
900 0 : result = 0;
901 : /* for passthrough, *blk_statp may be set */
902 0 : *blk_statp = BLK_STS_OK;
903 : }
904 : /*
905 : * Another corner case: the SCSI status byte is non-zero but 'good'.
906 : * Example: PRE-FETCH command returns SAM_STAT_CONDITION_MET when
907 : * it is able to fit nominated LBs in its cache (and SAM_STAT_GOOD
908 : * if it can't fit). Treat SAM_STAT_CONDITION_MET and the related
909 : * intermediate statuses (both obsolete in SAM-4) as good.
910 : */
911 0 : if (status_byte(result) && scsi_status_is_good(result)) {
912 0 : result = 0;
913 0 : *blk_statp = BLK_STS_OK;
914 : }
915 0 : return result;
916 : }
917 :
918 : /**
919 : * scsi_io_completion - Completion processing for SCSI commands.
920 : * @cmd: command that is finished.
921 : * @good_bytes: number of processed bytes.
922 : *
923 : * We will finish off the specified number of sectors. If we are done, the
924 : * command block will be released and the queue function will be goosed. If we
925 : * are not done then we have to figure out what to do next:
926 : *
927 : * a) We can call scsi_io_completion_reprep(). The request will be
928 : * unprepared and put back on the queue. Then a new command will
929 : * be created for it. This should be used if we made forward
930 : * progress, or if we want to switch from READ(10) to READ(6) for
931 : * example.
932 : *
933 : * b) We can call scsi_io_completion_action(). The request will be
934 : * put back on the queue and retried using the same command as
935 : * before, possibly after a delay.
936 : *
937 : * c) We can call scsi_end_request() with blk_stat other than
938 : * BLK_STS_OK, to fail the remainder of the request.
939 : */
940 0 : void scsi_io_completion(struct scsi_cmnd *cmd, unsigned int good_bytes)
941 : {
942 0 : int result = cmd->result;
943 0 : struct request_queue *q = cmd->device->request_queue;
944 0 : struct request *req = cmd->request;
945 0 : blk_status_t blk_stat = BLK_STS_OK;
946 :
947 0 : if (unlikely(result)) /* a nz result may or may not be an error */
948 0 : result = scsi_io_completion_nz_result(cmd, result, &blk_stat);
949 :
950 0 : if (unlikely(blk_rq_is_passthrough(req))) {
951 : /*
952 : * scsi_result_to_blk_status may have reset the host_byte
953 : */
954 0 : scsi_req(req)->result = cmd->result;
955 : }
956 :
957 : /*
958 : * Next deal with any sectors which we were able to correctly
959 : * handle.
960 : */
961 0 : SCSI_LOG_HLCOMPLETE(1, scmd_printk(KERN_INFO, cmd,
962 : "%u sectors total, %d bytes done.\n",
963 0 : blk_rq_sectors(req), good_bytes));
964 :
965 : /*
966 : * Failed, zero length commands always need to drop down
967 : * to retry code. Fast path should return in this block.
968 : */
969 0 : if (likely(blk_rq_bytes(req) > 0 || blk_stat == BLK_STS_OK)) {
970 0 : if (likely(!scsi_end_request(req, blk_stat, good_bytes)))
971 0 : return; /* no bytes remaining */
972 : }
973 :
974 : /* Kill remainder if no retries. */
975 0 : if (unlikely(blk_stat && scsi_noretry_cmd(cmd))) {
976 0 : if (scsi_end_request(req, blk_stat, blk_rq_bytes(req)))
977 0 : WARN_ONCE(true,
978 : "Bytes remaining after failed, no-retry command");
979 0 : return;
980 : }
981 :
982 : /*
983 : * If there had been no error, but we have leftover bytes in the
984 : * requeues just queue the command up again.
985 : */
986 0 : if (likely(result == 0))
987 0 : scsi_io_completion_reprep(cmd, q);
988 : else
989 0 : scsi_io_completion_action(cmd, result);
990 : }
991 :
992 0 : static inline bool scsi_cmd_needs_dma_drain(struct scsi_device *sdev,
993 : struct request *rq)
994 : {
995 0 : return sdev->dma_drain_len && blk_rq_is_passthrough(rq) &&
996 0 : !op_is_write(req_op(rq)) &&
997 0 : sdev->host->hostt->dma_need_drain(rq);
998 : }
999 :
1000 : /**
1001 : * scsi_alloc_sgtables - allocate S/G tables for a command
1002 : * @cmd: command descriptor we wish to initialize
1003 : *
1004 : * Returns:
1005 : * * BLK_STS_OK - on success
1006 : * * BLK_STS_RESOURCE - if the failure is retryable
1007 : * * BLK_STS_IOERR - if the failure is fatal
1008 : */
1009 0 : blk_status_t scsi_alloc_sgtables(struct scsi_cmnd *cmd)
1010 : {
1011 0 : struct scsi_device *sdev = cmd->device;
1012 0 : struct request *rq = cmd->request;
1013 0 : unsigned short nr_segs = blk_rq_nr_phys_segments(rq);
1014 0 : struct scatterlist *last_sg = NULL;
1015 0 : blk_status_t ret;
1016 0 : bool need_drain = scsi_cmd_needs_dma_drain(sdev, rq);
1017 0 : int count;
1018 :
1019 0 : if (WARN_ON_ONCE(!nr_segs))
1020 : return BLK_STS_IOERR;
1021 :
1022 : /*
1023 : * Make sure there is space for the drain. The driver must adjust
1024 : * max_hw_segments to be prepared for this.
1025 : */
1026 0 : if (need_drain)
1027 0 : nr_segs++;
1028 :
1029 : /*
1030 : * If sg table allocation fails, requeue request later.
1031 : */
1032 0 : if (unlikely(sg_alloc_table_chained(&cmd->sdb.table, nr_segs,
1033 : cmd->sdb.table.sgl, SCSI_INLINE_SG_CNT)))
1034 : return BLK_STS_RESOURCE;
1035 :
1036 : /*
1037 : * Next, walk the list, and fill in the addresses and sizes of
1038 : * each segment.
1039 : */
1040 0 : count = __blk_rq_map_sg(rq->q, rq, cmd->sdb.table.sgl, &last_sg);
1041 :
1042 0 : if (blk_rq_bytes(rq) & rq->q->dma_pad_mask) {
1043 0 : unsigned int pad_len =
1044 0 : (rq->q->dma_pad_mask & ~blk_rq_bytes(rq)) + 1;
1045 :
1046 0 : last_sg->length += pad_len;
1047 0 : cmd->extra_len += pad_len;
1048 : }
1049 :
1050 0 : if (need_drain) {
1051 0 : sg_unmark_end(last_sg);
1052 0 : last_sg = sg_next(last_sg);
1053 0 : sg_set_buf(last_sg, sdev->dma_drain_buf, sdev->dma_drain_len);
1054 0 : sg_mark_end(last_sg);
1055 :
1056 0 : cmd->extra_len += sdev->dma_drain_len;
1057 0 : count++;
1058 : }
1059 :
1060 0 : BUG_ON(count > cmd->sdb.table.nents);
1061 0 : cmd->sdb.table.nents = count;
1062 0 : cmd->sdb.length = blk_rq_payload_bytes(rq);
1063 :
1064 0 : if (blk_integrity_rq(rq)) {
1065 : struct scsi_data_buffer *prot_sdb = cmd->prot_sdb;
1066 : int ivecs;
1067 :
1068 : if (WARN_ON_ONCE(!prot_sdb)) {
1069 : /*
1070 : * This can happen if someone (e.g. multipath)
1071 : * queues a command to a device on an adapter
1072 : * that does not support DIX.
1073 : */
1074 : ret = BLK_STS_IOERR;
1075 : goto out_free_sgtables;
1076 : }
1077 :
1078 : ivecs = blk_rq_count_integrity_sg(rq->q, rq->bio);
1079 :
1080 : if (sg_alloc_table_chained(&prot_sdb->table, ivecs,
1081 : prot_sdb->table.sgl,
1082 : SCSI_INLINE_PROT_SG_CNT)) {
1083 : ret = BLK_STS_RESOURCE;
1084 : goto out_free_sgtables;
1085 : }
1086 :
1087 : count = blk_rq_map_integrity_sg(rq->q, rq->bio,
1088 : prot_sdb->table.sgl);
1089 : BUG_ON(count > ivecs);
1090 : BUG_ON(count > queue_max_integrity_segments(rq->q));
1091 :
1092 : cmd->prot_sdb = prot_sdb;
1093 : cmd->prot_sdb->table.nents = count;
1094 : }
1095 :
1096 0 : return BLK_STS_OK;
1097 : out_free_sgtables:
1098 : scsi_free_sgtables(cmd);
1099 : return ret;
1100 : }
1101 : EXPORT_SYMBOL(scsi_alloc_sgtables);
1102 :
1103 : /**
1104 : * scsi_initialize_rq - initialize struct scsi_cmnd partially
1105 : * @rq: Request associated with the SCSI command to be initialized.
1106 : *
1107 : * This function initializes the members of struct scsi_cmnd that must be
1108 : * initialized before request processing starts and that won't be
1109 : * reinitialized if a SCSI command is requeued.
1110 : *
1111 : * Called from inside blk_get_request() for pass-through requests and from
1112 : * inside scsi_init_command() for filesystem requests.
1113 : */
1114 0 : static void scsi_initialize_rq(struct request *rq)
1115 : {
1116 0 : struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(rq);
1117 :
1118 0 : scsi_req_init(&cmd->req);
1119 0 : init_rcu_head(&cmd->rcu);
1120 0 : cmd->jiffies_at_alloc = jiffies;
1121 0 : cmd->retries = 0;
1122 0 : }
1123 :
1124 : /*
1125 : * Only called when the request isn't completed by SCSI, and not freed by
1126 : * SCSI
1127 : */
1128 0 : static void scsi_cleanup_rq(struct request *rq)
1129 : {
1130 0 : if (rq->rq_flags & RQF_DONTPREP) {
1131 0 : scsi_mq_uninit_cmd(blk_mq_rq_to_pdu(rq));
1132 0 : rq->rq_flags &= ~RQF_DONTPREP;
1133 : }
1134 0 : }
1135 :
1136 : /* Called before a request is prepared. See also scsi_mq_prep_fn(). */
1137 0 : void scsi_init_command(struct scsi_device *dev, struct scsi_cmnd *cmd)
1138 : {
1139 0 : void *buf = cmd->sense_buffer;
1140 0 : void *prot = cmd->prot_sdb;
1141 0 : struct request *rq = blk_mq_rq_from_pdu(cmd);
1142 0 : unsigned int flags = cmd->flags & SCMD_PRESERVED_FLAGS;
1143 0 : unsigned long jiffies_at_alloc;
1144 0 : int retries, to_clear;
1145 0 : bool in_flight;
1146 :
1147 0 : if (!blk_rq_is_scsi(rq) && !(flags & SCMD_INITIALIZED)) {
1148 0 : flags |= SCMD_INITIALIZED;
1149 0 : scsi_initialize_rq(rq);
1150 : }
1151 :
1152 0 : jiffies_at_alloc = cmd->jiffies_at_alloc;
1153 0 : retries = cmd->retries;
1154 0 : in_flight = test_bit(SCMD_STATE_INFLIGHT, &cmd->state);
1155 : /*
1156 : * Zero out the cmd, except for the embedded scsi_request. Only clear
1157 : * the driver-private command data if the LLD does not supply a
1158 : * function to initialize that data.
1159 : */
1160 0 : to_clear = sizeof(*cmd) - sizeof(cmd->req);
1161 0 : if (!dev->host->hostt->init_cmd_priv)
1162 0 : to_clear += dev->host->hostt->cmd_size;
1163 0 : memset((char *)cmd + sizeof(cmd->req), 0, to_clear);
1164 :
1165 0 : cmd->device = dev;
1166 0 : cmd->sense_buffer = buf;
1167 0 : cmd->prot_sdb = prot;
1168 0 : cmd->flags = flags;
1169 0 : INIT_DELAYED_WORK(&cmd->abort_work, scmd_eh_abort_handler);
1170 0 : cmd->jiffies_at_alloc = jiffies_at_alloc;
1171 0 : cmd->retries = retries;
1172 0 : if (in_flight)
1173 0 : __set_bit(SCMD_STATE_INFLIGHT, &cmd->state);
1174 :
1175 0 : }
1176 :
1177 0 : static blk_status_t scsi_setup_scsi_cmnd(struct scsi_device *sdev,
1178 : struct request *req)
1179 : {
1180 0 : struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req);
1181 :
1182 : /*
1183 : * Passthrough requests may transfer data, in which case they must
1184 : * a bio attached to them. Or they might contain a SCSI command
1185 : * that does not transfer data, in which case they may optionally
1186 : * submit a request without an attached bio.
1187 : */
1188 0 : if (req->bio) {
1189 0 : blk_status_t ret = scsi_alloc_sgtables(cmd);
1190 0 : if (unlikely(ret != BLK_STS_OK))
1191 : return ret;
1192 : } else {
1193 0 : BUG_ON(blk_rq_bytes(req));
1194 :
1195 0 : memset(&cmd->sdb, 0, sizeof(cmd->sdb));
1196 : }
1197 :
1198 0 : cmd->cmd_len = scsi_req(req)->cmd_len;
1199 0 : if (cmd->cmd_len == 0)
1200 0 : cmd->cmd_len = scsi_command_size(cmd->cmnd);
1201 0 : cmd->cmnd = scsi_req(req)->cmd;
1202 0 : cmd->transfersize = blk_rq_bytes(req);
1203 0 : cmd->allowed = scsi_req(req)->retries;
1204 0 : return BLK_STS_OK;
1205 : }
1206 :
1207 : static blk_status_t
1208 0 : scsi_device_state_check(struct scsi_device *sdev, struct request *req)
1209 : {
1210 0 : switch (sdev->sdev_state) {
1211 : case SDEV_CREATED:
1212 : return BLK_STS_OK;
1213 0 : case SDEV_OFFLINE:
1214 : case SDEV_TRANSPORT_OFFLINE:
1215 : /*
1216 : * If the device is offline we refuse to process any
1217 : * commands. The device must be brought online
1218 : * before trying any recovery commands.
1219 : */
1220 0 : if (!sdev->offline_already) {
1221 0 : sdev->offline_already = true;
1222 0 : sdev_printk(KERN_ERR, sdev,
1223 : "rejecting I/O to offline device\n");
1224 : }
1225 : return BLK_STS_IOERR;
1226 0 : case SDEV_DEL:
1227 : /*
1228 : * If the device is fully deleted, we refuse to
1229 : * process any commands as well.
1230 : */
1231 0 : sdev_printk(KERN_ERR, sdev,
1232 : "rejecting I/O to dead device\n");
1233 0 : return BLK_STS_IOERR;
1234 0 : case SDEV_BLOCK:
1235 : case SDEV_CREATED_BLOCK:
1236 0 : return BLK_STS_RESOURCE;
1237 0 : case SDEV_QUIESCE:
1238 : /*
1239 : * If the device is blocked we only accept power management
1240 : * commands.
1241 : */
1242 0 : if (req && WARN_ON_ONCE(!(req->rq_flags & RQF_PM)))
1243 0 : return BLK_STS_RESOURCE;
1244 : return BLK_STS_OK;
1245 0 : default:
1246 : /*
1247 : * For any other not fully online state we only allow
1248 : * power management commands.
1249 : */
1250 0 : if (req && !(req->rq_flags & RQF_PM))
1251 0 : return BLK_STS_IOERR;
1252 : return BLK_STS_OK;
1253 : }
1254 : }
1255 :
1256 : /*
1257 : * scsi_dev_queue_ready: if we can send requests to sdev, return 1 else
1258 : * return 0.
1259 : *
1260 : * Called with the queue_lock held.
1261 : */
1262 0 : static inline int scsi_dev_queue_ready(struct request_queue *q,
1263 : struct scsi_device *sdev)
1264 : {
1265 0 : unsigned int busy;
1266 :
1267 0 : busy = atomic_inc_return(&sdev->device_busy) - 1;
1268 0 : if (atomic_read(&sdev->device_blocked)) {
1269 0 : if (busy)
1270 0 : goto out_dec;
1271 :
1272 : /*
1273 : * unblock after device_blocked iterates to zero
1274 : */
1275 0 : if (atomic_dec_return(&sdev->device_blocked) > 0)
1276 0 : goto out_dec;
1277 0 : SCSI_LOG_MLQUEUE(3, sdev_printk(KERN_INFO, sdev,
1278 0 : "unblocking device at zero depth\n"));
1279 : }
1280 :
1281 0 : if (busy >= sdev->queue_depth)
1282 0 : goto out_dec;
1283 :
1284 : return 1;
1285 0 : out_dec:
1286 0 : atomic_dec(&sdev->device_busy);
1287 0 : return 0;
1288 : }
1289 :
1290 : /*
1291 : * scsi_target_queue_ready: checks if there we can send commands to target
1292 : * @sdev: scsi device on starget to check.
1293 : */
1294 0 : static inline int scsi_target_queue_ready(struct Scsi_Host *shost,
1295 : struct scsi_device *sdev)
1296 : {
1297 0 : struct scsi_target *starget = scsi_target(sdev);
1298 0 : unsigned int busy;
1299 :
1300 0 : if (starget->single_lun) {
1301 0 : spin_lock_irq(shost->host_lock);
1302 0 : if (starget->starget_sdev_user &&
1303 : starget->starget_sdev_user != sdev) {
1304 0 : spin_unlock_irq(shost->host_lock);
1305 0 : return 0;
1306 : }
1307 0 : starget->starget_sdev_user = sdev;
1308 0 : spin_unlock_irq(shost->host_lock);
1309 : }
1310 :
1311 0 : if (starget->can_queue <= 0)
1312 : return 1;
1313 :
1314 0 : busy = atomic_inc_return(&starget->target_busy) - 1;
1315 0 : if (atomic_read(&starget->target_blocked) > 0) {
1316 0 : if (busy)
1317 0 : goto starved;
1318 :
1319 : /*
1320 : * unblock after target_blocked iterates to zero
1321 : */
1322 0 : if (atomic_dec_return(&starget->target_blocked) > 0)
1323 0 : goto out_dec;
1324 :
1325 0 : SCSI_LOG_MLQUEUE(3, starget_printk(KERN_INFO, starget,
1326 0 : "unblocking target at zero depth\n"));
1327 : }
1328 :
1329 0 : if (busy >= starget->can_queue)
1330 0 : goto starved;
1331 :
1332 : return 1;
1333 :
1334 0 : starved:
1335 0 : spin_lock_irq(shost->host_lock);
1336 0 : list_move_tail(&sdev->starved_entry, &shost->starved_list);
1337 0 : spin_unlock_irq(shost->host_lock);
1338 0 : out_dec:
1339 0 : if (starget->can_queue > 0)
1340 0 : atomic_dec(&starget->target_busy);
1341 : return 0;
1342 : }
1343 :
1344 : /*
1345 : * scsi_host_queue_ready: if we can send requests to shost, return 1 else
1346 : * return 0. We must end up running the queue again whenever 0 is
1347 : * returned, else IO can hang.
1348 : */
1349 0 : static inline int scsi_host_queue_ready(struct request_queue *q,
1350 : struct Scsi_Host *shost,
1351 : struct scsi_device *sdev,
1352 : struct scsi_cmnd *cmd)
1353 : {
1354 0 : if (scsi_host_in_recovery(shost))
1355 : return 0;
1356 :
1357 0 : if (atomic_read(&shost->host_blocked) > 0) {
1358 0 : if (scsi_host_busy(shost) > 0)
1359 0 : goto starved;
1360 :
1361 : /*
1362 : * unblock after host_blocked iterates to zero
1363 : */
1364 0 : if (atomic_dec_return(&shost->host_blocked) > 0)
1365 0 : goto out_dec;
1366 :
1367 0 : SCSI_LOG_MLQUEUE(3,
1368 : shost_printk(KERN_INFO, shost,
1369 0 : "unblocking host at zero depth\n"));
1370 : }
1371 :
1372 0 : if (shost->host_self_blocked)
1373 0 : goto starved;
1374 :
1375 : /* We're OK to process the command, so we can't be starved */
1376 0 : if (!list_empty(&sdev->starved_entry)) {
1377 0 : spin_lock_irq(shost->host_lock);
1378 0 : if (!list_empty(&sdev->starved_entry))
1379 0 : list_del_init(&sdev->starved_entry);
1380 0 : spin_unlock_irq(shost->host_lock);
1381 : }
1382 :
1383 0 : __set_bit(SCMD_STATE_INFLIGHT, &cmd->state);
1384 :
1385 0 : return 1;
1386 :
1387 0 : starved:
1388 0 : spin_lock_irq(shost->host_lock);
1389 0 : if (list_empty(&sdev->starved_entry))
1390 0 : list_add_tail(&sdev->starved_entry, &shost->starved_list);
1391 0 : spin_unlock_irq(shost->host_lock);
1392 0 : out_dec:
1393 0 : scsi_dec_host_busy(shost, cmd);
1394 0 : return 0;
1395 : }
1396 :
1397 : /*
1398 : * Busy state exporting function for request stacking drivers.
1399 : *
1400 : * For efficiency, no lock is taken to check the busy state of
1401 : * shost/starget/sdev, since the returned value is not guaranteed and
1402 : * may be changed after request stacking drivers call the function,
1403 : * regardless of taking lock or not.
1404 : *
1405 : * When scsi can't dispatch I/Os anymore and needs to kill I/Os scsi
1406 : * needs to return 'not busy'. Otherwise, request stacking drivers
1407 : * may hold requests forever.
1408 : */
1409 0 : static bool scsi_mq_lld_busy(struct request_queue *q)
1410 : {
1411 0 : struct scsi_device *sdev = q->queuedata;
1412 0 : struct Scsi_Host *shost;
1413 :
1414 0 : if (blk_queue_dying(q))
1415 : return false;
1416 :
1417 0 : shost = sdev->host;
1418 :
1419 : /*
1420 : * Ignore host/starget busy state.
1421 : * Since block layer does not have a concept of fairness across
1422 : * multiple queues, congestion of host/starget needs to be handled
1423 : * in SCSI layer.
1424 : */
1425 0 : if (scsi_host_in_recovery(shost) || scsi_device_is_busy(sdev))
1426 0 : return true;
1427 :
1428 : return false;
1429 : }
1430 :
1431 0 : static void scsi_softirq_done(struct request *rq)
1432 : {
1433 0 : struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(rq);
1434 0 : int disposition;
1435 :
1436 0 : INIT_LIST_HEAD(&cmd->eh_entry);
1437 :
1438 0 : atomic_inc(&cmd->device->iodone_cnt);
1439 0 : if (cmd->result)
1440 0 : atomic_inc(&cmd->device->ioerr_cnt);
1441 :
1442 0 : disposition = scsi_decide_disposition(cmd);
1443 0 : if (disposition != SUCCESS && scsi_cmd_runtime_exceeced(cmd))
1444 : disposition = SUCCESS;
1445 :
1446 0 : scsi_log_completion(cmd, disposition);
1447 :
1448 0 : switch (disposition) {
1449 0 : case SUCCESS:
1450 0 : scsi_finish_command(cmd);
1451 0 : break;
1452 : case NEEDS_RETRY:
1453 0 : scsi_queue_insert(cmd, SCSI_MLQUEUE_EH_RETRY);
1454 : break;
1455 : case ADD_TO_MLQUEUE:
1456 0 : scsi_queue_insert(cmd, SCSI_MLQUEUE_DEVICE_BUSY);
1457 : break;
1458 0 : default:
1459 0 : scsi_eh_scmd_add(cmd);
1460 0 : break;
1461 : }
1462 0 : }
1463 :
1464 : /**
1465 : * scsi_dispatch_cmd - Dispatch a command to the low-level driver.
1466 : * @cmd: command block we are dispatching.
1467 : *
1468 : * Return: nonzero return request was rejected and device's queue needs to be
1469 : * plugged.
1470 : */
1471 0 : static int scsi_dispatch_cmd(struct scsi_cmnd *cmd)
1472 : {
1473 0 : struct Scsi_Host *host = cmd->device->host;
1474 0 : int rtn = 0;
1475 :
1476 0 : atomic_inc(&cmd->device->iorequest_cnt);
1477 :
1478 : /* check if the device is still usable */
1479 0 : if (unlikely(cmd->device->sdev_state == SDEV_DEL)) {
1480 : /* in SDEV_DEL we error all commands. DID_NO_CONNECT
1481 : * returns an immediate error upwards, and signals
1482 : * that the device is no longer present */
1483 0 : cmd->result = DID_NO_CONNECT << 16;
1484 0 : goto done;
1485 : }
1486 :
1487 : /* Check to see if the scsi lld made this device blocked. */
1488 0 : if (unlikely(scsi_device_blocked(cmd->device))) {
1489 : /*
1490 : * in blocked state, the command is just put back on
1491 : * the device queue. The suspend state has already
1492 : * blocked the queue so future requests should not
1493 : * occur until the device transitions out of the
1494 : * suspend state.
1495 : */
1496 : SCSI_LOG_MLQUEUE(3, scmd_printk(KERN_INFO, cmd,
1497 : "queuecommand : device blocked\n"));
1498 : return SCSI_MLQUEUE_DEVICE_BUSY;
1499 : }
1500 :
1501 : /* Store the LUN value in cmnd, if needed. */
1502 0 : if (cmd->device->lun_in_cdb)
1503 0 : cmd->cmnd[1] = (cmd->cmnd[1] & 0x1f) |
1504 0 : (cmd->device->lun << 5 & 0xe0);
1505 :
1506 0 : scsi_log_send(cmd);
1507 :
1508 : /*
1509 : * Before we queue this command, check if the command
1510 : * length exceeds what the host adapter can handle.
1511 : */
1512 0 : if (cmd->cmd_len > cmd->device->host->max_cmd_len) {
1513 0 : SCSI_LOG_MLQUEUE(3, scmd_printk(KERN_INFO, cmd,
1514 : "queuecommand : command too long. "
1515 : "cdb_size=%d host->max_cmd_len=%d\n",
1516 0 : cmd->cmd_len, cmd->device->host->max_cmd_len));
1517 0 : cmd->result = (DID_ABORT << 16);
1518 0 : goto done;
1519 : }
1520 :
1521 0 : if (unlikely(host->shost_state == SHOST_DEL)) {
1522 0 : cmd->result = (DID_NO_CONNECT << 16);
1523 0 : goto done;
1524 :
1525 : }
1526 :
1527 0 : trace_scsi_dispatch_cmd_start(cmd);
1528 0 : rtn = host->hostt->queuecommand(host, cmd);
1529 0 : if (rtn) {
1530 0 : trace_scsi_dispatch_cmd_error(cmd, rtn);
1531 0 : if (rtn != SCSI_MLQUEUE_DEVICE_BUSY &&
1532 0 : rtn != SCSI_MLQUEUE_TARGET_BUSY)
1533 0 : rtn = SCSI_MLQUEUE_HOST_BUSY;
1534 :
1535 : SCSI_LOG_MLQUEUE(3, scmd_printk(KERN_INFO, cmd,
1536 : "queuecommand : request rejected\n"));
1537 : }
1538 :
1539 : return rtn;
1540 0 : done:
1541 0 : cmd->scsi_done(cmd);
1542 0 : return 0;
1543 : }
1544 :
1545 : /* Size in bytes of the sg-list stored in the scsi-mq command-private data. */
1546 0 : static unsigned int scsi_mq_inline_sgl_size(struct Scsi_Host *shost)
1547 : {
1548 0 : return min_t(unsigned int, shost->sg_tablesize, SCSI_INLINE_SG_CNT) *
1549 : sizeof(struct scatterlist);
1550 : }
1551 :
1552 0 : static blk_status_t scsi_prepare_cmd(struct request *req)
1553 : {
1554 0 : struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req);
1555 0 : struct scsi_device *sdev = req->q->queuedata;
1556 0 : struct Scsi_Host *shost = sdev->host;
1557 0 : struct scatterlist *sg;
1558 :
1559 0 : scsi_init_command(sdev, cmd);
1560 :
1561 0 : cmd->request = req;
1562 0 : cmd->tag = req->tag;
1563 0 : cmd->prot_op = SCSI_PROT_NORMAL;
1564 0 : if (blk_rq_bytes(req))
1565 0 : cmd->sc_data_direction = rq_dma_dir(req);
1566 : else
1567 0 : cmd->sc_data_direction = DMA_NONE;
1568 :
1569 0 : sg = (void *)cmd + sizeof(struct scsi_cmnd) + shost->hostt->cmd_size;
1570 0 : cmd->sdb.table.sgl = sg;
1571 :
1572 0 : if (scsi_host_get_prot(shost)) {
1573 0 : memset(cmd->prot_sdb, 0, sizeof(struct scsi_data_buffer));
1574 :
1575 0 : cmd->prot_sdb->table.sgl =
1576 0 : (struct scatterlist *)(cmd->prot_sdb + 1);
1577 : }
1578 :
1579 : /*
1580 : * Special handling for passthrough commands, which don't go to the ULP
1581 : * at all:
1582 : */
1583 0 : if (blk_rq_is_scsi(req))
1584 0 : return scsi_setup_scsi_cmnd(sdev, req);
1585 :
1586 0 : if (sdev->handler && sdev->handler->prep_fn) {
1587 0 : blk_status_t ret = sdev->handler->prep_fn(sdev, req);
1588 :
1589 0 : if (ret != BLK_STS_OK)
1590 : return ret;
1591 : }
1592 :
1593 0 : cmd->cmnd = scsi_req(req)->cmd = scsi_req(req)->__cmd;
1594 0 : memset(cmd->cmnd, 0, BLK_MAX_CDB);
1595 0 : return scsi_cmd_to_driver(cmd)->init_command(cmd);
1596 : }
1597 :
1598 0 : static void scsi_mq_done(struct scsi_cmnd *cmd)
1599 : {
1600 0 : if (unlikely(blk_should_fake_timeout(cmd->request->q)))
1601 : return;
1602 0 : if (unlikely(test_and_set_bit(SCMD_STATE_COMPLETE, &cmd->state)))
1603 : return;
1604 0 : trace_scsi_dispatch_cmd_done(cmd);
1605 0 : blk_mq_complete_request(cmd->request);
1606 : }
1607 :
1608 0 : static void scsi_mq_put_budget(struct request_queue *q)
1609 : {
1610 0 : struct scsi_device *sdev = q->queuedata;
1611 :
1612 0 : atomic_dec(&sdev->device_busy);
1613 0 : }
1614 :
1615 0 : static bool scsi_mq_get_budget(struct request_queue *q)
1616 : {
1617 0 : struct scsi_device *sdev = q->queuedata;
1618 :
1619 0 : if (scsi_dev_queue_ready(q, sdev))
1620 : return true;
1621 :
1622 0 : atomic_inc(&sdev->restarts);
1623 :
1624 : /*
1625 : * Orders atomic_inc(&sdev->restarts) and atomic_read(&sdev->device_busy).
1626 : * .restarts must be incremented before .device_busy is read because the
1627 : * code in scsi_run_queue_async() depends on the order of these operations.
1628 : */
1629 0 : smp_mb__after_atomic();
1630 :
1631 : /*
1632 : * If all in-flight requests originated from this LUN are completed
1633 : * before reading .device_busy, sdev->device_busy will be observed as
1634 : * zero, then blk_mq_delay_run_hw_queues() will dispatch this request
1635 : * soon. Otherwise, completion of one of these requests will observe
1636 : * the .restarts flag, and the request queue will be run for handling
1637 : * this request, see scsi_end_request().
1638 : */
1639 0 : if (unlikely(atomic_read(&sdev->device_busy) == 0 &&
1640 : !scsi_device_blocked(sdev)))
1641 0 : blk_mq_delay_run_hw_queues(sdev->request_queue, SCSI_QUEUE_DELAY);
1642 : return false;
1643 : }
1644 :
1645 0 : static blk_status_t scsi_queue_rq(struct blk_mq_hw_ctx *hctx,
1646 : const struct blk_mq_queue_data *bd)
1647 : {
1648 0 : struct request *req = bd->rq;
1649 0 : struct request_queue *q = req->q;
1650 0 : struct scsi_device *sdev = q->queuedata;
1651 0 : struct Scsi_Host *shost = sdev->host;
1652 0 : struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(req);
1653 0 : blk_status_t ret;
1654 0 : int reason;
1655 :
1656 : /*
1657 : * If the device is not in running state we will reject some or all
1658 : * commands.
1659 : */
1660 0 : if (unlikely(sdev->sdev_state != SDEV_RUNNING)) {
1661 0 : ret = scsi_device_state_check(sdev, req);
1662 0 : if (ret != BLK_STS_OK)
1663 0 : goto out_put_budget;
1664 : }
1665 :
1666 0 : ret = BLK_STS_RESOURCE;
1667 0 : if (!scsi_target_queue_ready(shost, sdev))
1668 0 : goto out_put_budget;
1669 0 : if (!scsi_host_queue_ready(q, shost, sdev, cmd))
1670 0 : goto out_dec_target_busy;
1671 :
1672 0 : if (!(req->rq_flags & RQF_DONTPREP)) {
1673 0 : ret = scsi_prepare_cmd(req);
1674 0 : if (ret != BLK_STS_OK)
1675 0 : goto out_dec_host_busy;
1676 0 : req->rq_flags |= RQF_DONTPREP;
1677 : } else {
1678 0 : clear_bit(SCMD_STATE_COMPLETE, &cmd->state);
1679 : }
1680 :
1681 0 : cmd->flags &= SCMD_PRESERVED_FLAGS;
1682 0 : if (sdev->simple_tags)
1683 0 : cmd->flags |= SCMD_TAGGED;
1684 0 : if (bd->last)
1685 0 : cmd->flags |= SCMD_LAST;
1686 :
1687 0 : scsi_set_resid(cmd, 0);
1688 0 : memset(cmd->sense_buffer, 0, SCSI_SENSE_BUFFERSIZE);
1689 0 : cmd->scsi_done = scsi_mq_done;
1690 :
1691 0 : blk_mq_start_request(req);
1692 0 : reason = scsi_dispatch_cmd(cmd);
1693 0 : if (reason) {
1694 0 : scsi_set_blocked(cmd, reason);
1695 0 : ret = BLK_STS_RESOURCE;
1696 0 : goto out_dec_host_busy;
1697 : }
1698 :
1699 : return BLK_STS_OK;
1700 :
1701 0 : out_dec_host_busy:
1702 0 : scsi_dec_host_busy(shost, cmd);
1703 0 : out_dec_target_busy:
1704 0 : if (scsi_target(sdev)->can_queue > 0)
1705 0 : atomic_dec(&scsi_target(sdev)->target_busy);
1706 0 : out_put_budget:
1707 0 : scsi_mq_put_budget(q);
1708 0 : switch (ret) {
1709 : case BLK_STS_OK:
1710 : break;
1711 : case BLK_STS_RESOURCE:
1712 : case BLK_STS_ZONE_RESOURCE:
1713 0 : if (scsi_device_blocked(sdev))
1714 0 : ret = BLK_STS_DEV_RESOURCE;
1715 : break;
1716 : case BLK_STS_AGAIN:
1717 0 : scsi_req(req)->result = DID_BUS_BUSY << 16;
1718 0 : if (req->rq_flags & RQF_DONTPREP)
1719 0 : scsi_mq_uninit_cmd(cmd);
1720 : break;
1721 : default:
1722 0 : if (unlikely(!scsi_device_online(sdev)))
1723 0 : scsi_req(req)->result = DID_NO_CONNECT << 16;
1724 : else
1725 0 : scsi_req(req)->result = DID_ERROR << 16;
1726 : /*
1727 : * Make sure to release all allocated resources when
1728 : * we hit an error, as we will never see this command
1729 : * again.
1730 : */
1731 0 : if (req->rq_flags & RQF_DONTPREP)
1732 0 : scsi_mq_uninit_cmd(cmd);
1733 0 : scsi_run_queue_async(sdev);
1734 0 : break;
1735 : }
1736 : return ret;
1737 : }
1738 :
1739 0 : static enum blk_eh_timer_return scsi_timeout(struct request *req,
1740 : bool reserved)
1741 : {
1742 0 : if (reserved)
1743 : return BLK_EH_RESET_TIMER;
1744 0 : return scsi_times_out(req);
1745 : }
1746 :
1747 0 : static int scsi_mq_init_request(struct blk_mq_tag_set *set, struct request *rq,
1748 : unsigned int hctx_idx, unsigned int numa_node)
1749 : {
1750 0 : struct Scsi_Host *shost = set->driver_data;
1751 0 : const bool unchecked_isa_dma = shost->unchecked_isa_dma;
1752 0 : struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(rq);
1753 0 : struct scatterlist *sg;
1754 0 : int ret = 0;
1755 :
1756 0 : if (unchecked_isa_dma)
1757 0 : cmd->flags |= SCMD_UNCHECKED_ISA_DMA;
1758 0 : cmd->sense_buffer = scsi_alloc_sense_buffer(unchecked_isa_dma,
1759 : GFP_KERNEL, numa_node);
1760 0 : if (!cmd->sense_buffer)
1761 : return -ENOMEM;
1762 0 : cmd->req.sense = cmd->sense_buffer;
1763 :
1764 0 : if (scsi_host_get_prot(shost)) {
1765 0 : sg = (void *)cmd + sizeof(struct scsi_cmnd) +
1766 0 : shost->hostt->cmd_size;
1767 0 : cmd->prot_sdb = (void *)sg + scsi_mq_inline_sgl_size(shost);
1768 : }
1769 :
1770 0 : if (shost->hostt->init_cmd_priv) {
1771 0 : ret = shost->hostt->init_cmd_priv(shost, cmd);
1772 0 : if (ret < 0)
1773 0 : scsi_free_sense_buffer(unchecked_isa_dma,
1774 : cmd->sense_buffer);
1775 : }
1776 :
1777 : return ret;
1778 : }
1779 :
1780 0 : static void scsi_mq_exit_request(struct blk_mq_tag_set *set, struct request *rq,
1781 : unsigned int hctx_idx)
1782 : {
1783 0 : struct Scsi_Host *shost = set->driver_data;
1784 0 : struct scsi_cmnd *cmd = blk_mq_rq_to_pdu(rq);
1785 :
1786 0 : if (shost->hostt->exit_cmd_priv)
1787 0 : shost->hostt->exit_cmd_priv(shost, cmd);
1788 0 : scsi_free_sense_buffer(cmd->flags & SCMD_UNCHECKED_ISA_DMA,
1789 : cmd->sense_buffer);
1790 0 : }
1791 :
1792 0 : static int scsi_map_queues(struct blk_mq_tag_set *set)
1793 : {
1794 0 : struct Scsi_Host *shost = container_of(set, struct Scsi_Host, tag_set);
1795 :
1796 0 : if (shost->hostt->map_queues)
1797 0 : return shost->hostt->map_queues(shost);
1798 0 : return blk_mq_map_queues(&set->map[HCTX_TYPE_DEFAULT]);
1799 : }
1800 :
1801 0 : void __scsi_init_queue(struct Scsi_Host *shost, struct request_queue *q)
1802 : {
1803 0 : struct device *dev = shost->dma_dev;
1804 :
1805 : /*
1806 : * this limit is imposed by hardware restrictions
1807 : */
1808 0 : blk_queue_max_segments(q, min_t(unsigned short, shost->sg_tablesize,
1809 : SG_MAX_SEGMENTS));
1810 :
1811 0 : if (scsi_host_prot_dma(shost)) {
1812 0 : shost->sg_prot_tablesize =
1813 0 : min_not_zero(shost->sg_prot_tablesize,
1814 : (unsigned short)SCSI_MAX_PROT_SG_SEGMENTS);
1815 0 : BUG_ON(shost->sg_prot_tablesize < shost->sg_tablesize);
1816 0 : blk_queue_max_integrity_segments(q, shost->sg_prot_tablesize);
1817 : }
1818 :
1819 0 : if (dev->dma_mask) {
1820 0 : shost->max_sectors = min_t(unsigned int, shost->max_sectors,
1821 : dma_max_mapping_size(dev) >> SECTOR_SHIFT);
1822 : }
1823 0 : blk_queue_max_hw_sectors(q, shost->max_sectors);
1824 0 : if (shost->unchecked_isa_dma)
1825 0 : blk_queue_bounce_limit(q, BLK_BOUNCE_ISA);
1826 0 : blk_queue_segment_boundary(q, shost->dma_boundary);
1827 0 : dma_set_seg_boundary(dev, shost->dma_boundary);
1828 :
1829 0 : blk_queue_max_segment_size(q, shost->max_segment_size);
1830 0 : blk_queue_virt_boundary(q, shost->virt_boundary_mask);
1831 0 : dma_set_max_seg_size(dev, queue_max_segment_size(q));
1832 :
1833 : /*
1834 : * Set a reasonable default alignment: The larger of 32-byte (dword),
1835 : * which is a common minimum for HBAs, and the minimum DMA alignment,
1836 : * which is set by the platform.
1837 : *
1838 : * Devices that require a bigger alignment can increase it later.
1839 : */
1840 0 : blk_queue_dma_alignment(q, max(4, dma_get_cache_alignment()) - 1);
1841 0 : }
1842 : EXPORT_SYMBOL_GPL(__scsi_init_queue);
1843 :
1844 : static const struct blk_mq_ops scsi_mq_ops_no_commit = {
1845 : .get_budget = scsi_mq_get_budget,
1846 : .put_budget = scsi_mq_put_budget,
1847 : .queue_rq = scsi_queue_rq,
1848 : .complete = scsi_softirq_done,
1849 : .timeout = scsi_timeout,
1850 : #ifdef CONFIG_BLK_DEBUG_FS
1851 : .show_rq = scsi_show_rq,
1852 : #endif
1853 : .init_request = scsi_mq_init_request,
1854 : .exit_request = scsi_mq_exit_request,
1855 : .initialize_rq_fn = scsi_initialize_rq,
1856 : .cleanup_rq = scsi_cleanup_rq,
1857 : .busy = scsi_mq_lld_busy,
1858 : .map_queues = scsi_map_queues,
1859 : };
1860 :
1861 :
1862 0 : static void scsi_commit_rqs(struct blk_mq_hw_ctx *hctx)
1863 : {
1864 0 : struct request_queue *q = hctx->queue;
1865 0 : struct scsi_device *sdev = q->queuedata;
1866 0 : struct Scsi_Host *shost = sdev->host;
1867 :
1868 0 : shost->hostt->commit_rqs(shost, hctx->queue_num);
1869 0 : }
1870 :
1871 : static const struct blk_mq_ops scsi_mq_ops = {
1872 : .get_budget = scsi_mq_get_budget,
1873 : .put_budget = scsi_mq_put_budget,
1874 : .queue_rq = scsi_queue_rq,
1875 : .commit_rqs = scsi_commit_rqs,
1876 : .complete = scsi_softirq_done,
1877 : .timeout = scsi_timeout,
1878 : #ifdef CONFIG_BLK_DEBUG_FS
1879 : .show_rq = scsi_show_rq,
1880 : #endif
1881 : .init_request = scsi_mq_init_request,
1882 : .exit_request = scsi_mq_exit_request,
1883 : .initialize_rq_fn = scsi_initialize_rq,
1884 : .cleanup_rq = scsi_cleanup_rq,
1885 : .busy = scsi_mq_lld_busy,
1886 : .map_queues = scsi_map_queues,
1887 : };
1888 :
1889 0 : struct request_queue *scsi_mq_alloc_queue(struct scsi_device *sdev)
1890 : {
1891 0 : sdev->request_queue = blk_mq_init_queue(&sdev->host->tag_set);
1892 0 : if (IS_ERR(sdev->request_queue))
1893 : return NULL;
1894 :
1895 0 : sdev->request_queue->queuedata = sdev;
1896 0 : __scsi_init_queue(sdev->host, sdev->request_queue);
1897 0 : blk_queue_flag_set(QUEUE_FLAG_SCSI_PASSTHROUGH, sdev->request_queue);
1898 0 : return sdev->request_queue;
1899 : }
1900 :
1901 0 : int scsi_mq_setup_tags(struct Scsi_Host *shost)
1902 : {
1903 0 : unsigned int cmd_size, sgl_size;
1904 0 : struct blk_mq_tag_set *tag_set = &shost->tag_set;
1905 :
1906 0 : sgl_size = max_t(unsigned int, sizeof(struct scatterlist),
1907 : scsi_mq_inline_sgl_size(shost));
1908 0 : cmd_size = sizeof(struct scsi_cmnd) + shost->hostt->cmd_size + sgl_size;
1909 0 : if (scsi_host_get_prot(shost))
1910 0 : cmd_size += sizeof(struct scsi_data_buffer) +
1911 : sizeof(struct scatterlist) * SCSI_INLINE_PROT_SG_CNT;
1912 :
1913 0 : memset(tag_set, 0, sizeof(*tag_set));
1914 0 : if (shost->hostt->commit_rqs)
1915 0 : tag_set->ops = &scsi_mq_ops;
1916 : else
1917 0 : tag_set->ops = &scsi_mq_ops_no_commit;
1918 0 : tag_set->nr_hw_queues = shost->nr_hw_queues ? : 1;
1919 0 : tag_set->queue_depth = shost->can_queue;
1920 0 : tag_set->cmd_size = cmd_size;
1921 0 : tag_set->numa_node = NUMA_NO_NODE;
1922 0 : tag_set->flags = BLK_MQ_F_SHOULD_MERGE;
1923 0 : tag_set->flags |=
1924 0 : BLK_ALLOC_POLICY_TO_MQ_FLAG(shost->hostt->tag_alloc_policy);
1925 0 : tag_set->driver_data = shost;
1926 0 : if (shost->host_tagset)
1927 0 : tag_set->flags |= BLK_MQ_F_TAG_HCTX_SHARED;
1928 :
1929 0 : return blk_mq_alloc_tag_set(tag_set);
1930 : }
1931 :
1932 0 : void scsi_mq_destroy_tags(struct Scsi_Host *shost)
1933 : {
1934 0 : blk_mq_free_tag_set(&shost->tag_set);
1935 0 : }
1936 :
1937 : /**
1938 : * scsi_device_from_queue - return sdev associated with a request_queue
1939 : * @q: The request queue to return the sdev from
1940 : *
1941 : * Return the sdev associated with a request queue or NULL if the
1942 : * request_queue does not reference a SCSI device.
1943 : */
1944 0 : struct scsi_device *scsi_device_from_queue(struct request_queue *q)
1945 : {
1946 0 : struct scsi_device *sdev = NULL;
1947 :
1948 0 : if (q->mq_ops == &scsi_mq_ops_no_commit ||
1949 : q->mq_ops == &scsi_mq_ops)
1950 0 : sdev = q->queuedata;
1951 0 : if (!sdev || !get_device(&sdev->sdev_gendev))
1952 : sdev = NULL;
1953 :
1954 0 : return sdev;
1955 : }
1956 :
1957 : /**
1958 : * scsi_block_requests - Utility function used by low-level drivers to prevent
1959 : * further commands from being queued to the device.
1960 : * @shost: host in question
1961 : *
1962 : * There is no timer nor any other means by which the requests get unblocked
1963 : * other than the low-level driver calling scsi_unblock_requests().
1964 : */
1965 0 : void scsi_block_requests(struct Scsi_Host *shost)
1966 : {
1967 0 : shost->host_self_blocked = 1;
1968 0 : }
1969 : EXPORT_SYMBOL(scsi_block_requests);
1970 :
1971 : /**
1972 : * scsi_unblock_requests - Utility function used by low-level drivers to allow
1973 : * further commands to be queued to the device.
1974 : * @shost: host in question
1975 : *
1976 : * There is no timer nor any other means by which the requests get unblocked
1977 : * other than the low-level driver calling scsi_unblock_requests(). This is done
1978 : * as an API function so that changes to the internals of the scsi mid-layer
1979 : * won't require wholesale changes to drivers that use this feature.
1980 : */
1981 0 : void scsi_unblock_requests(struct Scsi_Host *shost)
1982 : {
1983 0 : shost->host_self_blocked = 0;
1984 0 : scsi_run_host_queues(shost);
1985 0 : }
1986 : EXPORT_SYMBOL(scsi_unblock_requests);
1987 :
1988 0 : void scsi_exit_queue(void)
1989 : {
1990 0 : kmem_cache_destroy(scsi_sense_cache);
1991 0 : kmem_cache_destroy(scsi_sense_isadma_cache);
1992 0 : }
1993 :
1994 : /**
1995 : * scsi_mode_select - issue a mode select
1996 : * @sdev: SCSI device to be queried
1997 : * @pf: Page format bit (1 == standard, 0 == vendor specific)
1998 : * @sp: Save page bit (0 == don't save, 1 == save)
1999 : * @modepage: mode page being requested
2000 : * @buffer: request buffer (may not be smaller than eight bytes)
2001 : * @len: length of request buffer.
2002 : * @timeout: command timeout
2003 : * @retries: number of retries before failing
2004 : * @data: returns a structure abstracting the mode header data
2005 : * @sshdr: place to put sense data (or NULL if no sense to be collected).
2006 : * must be SCSI_SENSE_BUFFERSIZE big.
2007 : *
2008 : * Returns zero if successful; negative error number or scsi
2009 : * status on error
2010 : *
2011 : */
2012 : int
2013 0 : scsi_mode_select(struct scsi_device *sdev, int pf, int sp, int modepage,
2014 : unsigned char *buffer, int len, int timeout, int retries,
2015 : struct scsi_mode_data *data, struct scsi_sense_hdr *sshdr)
2016 : {
2017 0 : unsigned char cmd[10];
2018 0 : unsigned char *real_buffer;
2019 0 : int ret;
2020 :
2021 0 : memset(cmd, 0, sizeof(cmd));
2022 0 : cmd[1] = (pf ? 0x10 : 0) | (sp ? 0x01 : 0);
2023 :
2024 0 : if (sdev->use_10_for_ms) {
2025 0 : if (len > 65535)
2026 : return -EINVAL;
2027 0 : real_buffer = kmalloc(8 + len, GFP_KERNEL);
2028 0 : if (!real_buffer)
2029 : return -ENOMEM;
2030 0 : memcpy(real_buffer + 8, buffer, len);
2031 0 : len += 8;
2032 0 : real_buffer[0] = 0;
2033 0 : real_buffer[1] = 0;
2034 0 : real_buffer[2] = data->medium_type;
2035 0 : real_buffer[3] = data->device_specific;
2036 0 : real_buffer[4] = data->longlba ? 0x01 : 0;
2037 0 : real_buffer[5] = 0;
2038 0 : real_buffer[6] = data->block_descriptor_length >> 8;
2039 0 : real_buffer[7] = data->block_descriptor_length;
2040 :
2041 0 : cmd[0] = MODE_SELECT_10;
2042 0 : cmd[7] = len >> 8;
2043 0 : cmd[8] = len;
2044 : } else {
2045 0 : if (len > 255 || data->block_descriptor_length > 255 ||
2046 : data->longlba)
2047 : return -EINVAL;
2048 :
2049 0 : real_buffer = kmalloc(4 + len, GFP_KERNEL);
2050 0 : if (!real_buffer)
2051 : return -ENOMEM;
2052 0 : memcpy(real_buffer + 4, buffer, len);
2053 0 : len += 4;
2054 0 : real_buffer[0] = 0;
2055 0 : real_buffer[1] = data->medium_type;
2056 0 : real_buffer[2] = data->device_specific;
2057 0 : real_buffer[3] = data->block_descriptor_length;
2058 :
2059 0 : cmd[0] = MODE_SELECT;
2060 0 : cmd[4] = len;
2061 : }
2062 :
2063 0 : ret = scsi_execute_req(sdev, cmd, DMA_TO_DEVICE, real_buffer, len,
2064 : sshdr, timeout, retries, NULL);
2065 0 : kfree(real_buffer);
2066 0 : return ret;
2067 : }
2068 : EXPORT_SYMBOL_GPL(scsi_mode_select);
2069 :
2070 : /**
2071 : * scsi_mode_sense - issue a mode sense, falling back from 10 to six bytes if necessary.
2072 : * @sdev: SCSI device to be queried
2073 : * @dbd: set if mode sense will allow block descriptors to be returned
2074 : * @modepage: mode page being requested
2075 : * @buffer: request buffer (may not be smaller than eight bytes)
2076 : * @len: length of request buffer.
2077 : * @timeout: command timeout
2078 : * @retries: number of retries before failing
2079 : * @data: returns a structure abstracting the mode header data
2080 : * @sshdr: place to put sense data (or NULL if no sense to be collected).
2081 : * must be SCSI_SENSE_BUFFERSIZE big.
2082 : *
2083 : * Returns zero if unsuccessful, or the header offset (either 4
2084 : * or 8 depending on whether a six or ten byte command was
2085 : * issued) if successful.
2086 : */
2087 : int
2088 0 : scsi_mode_sense(struct scsi_device *sdev, int dbd, int modepage,
2089 : unsigned char *buffer, int len, int timeout, int retries,
2090 : struct scsi_mode_data *data, struct scsi_sense_hdr *sshdr)
2091 : {
2092 0 : unsigned char cmd[12];
2093 0 : int use_10_for_ms;
2094 0 : int header_length;
2095 0 : int result, retry_count = retries;
2096 0 : struct scsi_sense_hdr my_sshdr;
2097 :
2098 0 : memset(data, 0, sizeof(*data));
2099 0 : memset(&cmd[0], 0, 12);
2100 :
2101 0 : dbd = sdev->set_dbd_for_ms ? 8 : dbd;
2102 0 : cmd[1] = dbd & 0x18; /* allows DBD and LLBA bits */
2103 0 : cmd[2] = modepage;
2104 :
2105 : /* caller might not be interested in sense, but we need it */
2106 0 : if (!sshdr)
2107 0 : sshdr = &my_sshdr;
2108 :
2109 0 : retry:
2110 0 : use_10_for_ms = sdev->use_10_for_ms;
2111 :
2112 0 : if (use_10_for_ms) {
2113 0 : if (len < 8)
2114 : len = 8;
2115 :
2116 0 : cmd[0] = MODE_SENSE_10;
2117 0 : cmd[8] = len;
2118 0 : header_length = 8;
2119 : } else {
2120 0 : if (len < 4)
2121 : len = 4;
2122 :
2123 0 : cmd[0] = MODE_SENSE;
2124 0 : cmd[4] = len;
2125 0 : header_length = 4;
2126 : }
2127 :
2128 0 : memset(buffer, 0, len);
2129 :
2130 0 : result = scsi_execute_req(sdev, cmd, DMA_FROM_DEVICE, buffer, len,
2131 : sshdr, timeout, retries, NULL);
2132 :
2133 : /* This code looks awful: what it's doing is making sure an
2134 : * ILLEGAL REQUEST sense return identifies the actual command
2135 : * byte as the problem. MODE_SENSE commands can return
2136 : * ILLEGAL REQUEST if the code page isn't supported */
2137 :
2138 0 : if (use_10_for_ms && !scsi_status_is_good(result) &&
2139 0 : driver_byte(result) == DRIVER_SENSE) {
2140 0 : if (scsi_sense_valid(sshdr)) {
2141 0 : if ((sshdr->sense_key == ILLEGAL_REQUEST) &&
2142 0 : (sshdr->asc == 0x20) && (sshdr->ascq == 0)) {
2143 : /*
2144 : * Invalid command operation code
2145 : */
2146 0 : sdev->use_10_for_ms = 0;
2147 0 : goto retry;
2148 : }
2149 : }
2150 : }
2151 :
2152 0 : if (scsi_status_is_good(result)) {
2153 0 : if (unlikely(buffer[0] == 0x86 && buffer[1] == 0x0b &&
2154 : (modepage == 6 || modepage == 8))) {
2155 : /* Initio breakage? */
2156 0 : header_length = 0;
2157 0 : data->length = 13;
2158 0 : data->medium_type = 0;
2159 0 : data->device_specific = 0;
2160 0 : data->longlba = 0;
2161 0 : data->block_descriptor_length = 0;
2162 0 : } else if (use_10_for_ms) {
2163 0 : data->length = buffer[0]*256 + buffer[1] + 2;
2164 0 : data->medium_type = buffer[2];
2165 0 : data->device_specific = buffer[3];
2166 0 : data->longlba = buffer[4] & 0x01;
2167 0 : data->block_descriptor_length = buffer[6]*256
2168 0 : + buffer[7];
2169 : } else {
2170 0 : data->length = buffer[0] + 1;
2171 0 : data->medium_type = buffer[1];
2172 0 : data->device_specific = buffer[2];
2173 0 : data->block_descriptor_length = buffer[3];
2174 : }
2175 0 : data->header_length = header_length;
2176 0 : } else if ((status_byte(result) == CHECK_CONDITION) &&
2177 0 : scsi_sense_valid(sshdr) &&
2178 0 : sshdr->sense_key == UNIT_ATTENTION && retry_count) {
2179 0 : retry_count--;
2180 0 : goto retry;
2181 : }
2182 :
2183 0 : return result;
2184 : }
2185 : EXPORT_SYMBOL(scsi_mode_sense);
2186 :
2187 : /**
2188 : * scsi_test_unit_ready - test if unit is ready
2189 : * @sdev: scsi device to change the state of.
2190 : * @timeout: command timeout
2191 : * @retries: number of retries before failing
2192 : * @sshdr: outpout pointer for decoded sense information.
2193 : *
2194 : * Returns zero if unsuccessful or an error if TUR failed. For
2195 : * removable media, UNIT_ATTENTION sets ->changed flag.
2196 : **/
2197 : int
2198 0 : scsi_test_unit_ready(struct scsi_device *sdev, int timeout, int retries,
2199 : struct scsi_sense_hdr *sshdr)
2200 : {
2201 0 : char cmd[] = {
2202 : TEST_UNIT_READY, 0, 0, 0, 0, 0,
2203 : };
2204 0 : int result;
2205 :
2206 : /* try to eat the UNIT_ATTENTION if there are enough retries */
2207 0 : do {
2208 0 : result = scsi_execute_req(sdev, cmd, DMA_NONE, NULL, 0, sshdr,
2209 : timeout, 1, NULL);
2210 0 : if (sdev->removable && scsi_sense_valid(sshdr) &&
2211 0 : sshdr->sense_key == UNIT_ATTENTION)
2212 0 : sdev->changed = 1;
2213 0 : } while (scsi_sense_valid(sshdr) &&
2214 0 : sshdr->sense_key == UNIT_ATTENTION && --retries);
2215 :
2216 0 : return result;
2217 : }
2218 : EXPORT_SYMBOL(scsi_test_unit_ready);
2219 :
2220 : /**
2221 : * scsi_device_set_state - Take the given device through the device state model.
2222 : * @sdev: scsi device to change the state of.
2223 : * @state: state to change to.
2224 : *
2225 : * Returns zero if successful or an error if the requested
2226 : * transition is illegal.
2227 : */
2228 : int
2229 0 : scsi_device_set_state(struct scsi_device *sdev, enum scsi_device_state state)
2230 : {
2231 0 : enum scsi_device_state oldstate = sdev->sdev_state;
2232 :
2233 0 : if (state == oldstate)
2234 : return 0;
2235 :
2236 0 : switch (state) {
2237 0 : case SDEV_CREATED:
2238 0 : switch (oldstate) {
2239 : case SDEV_CREATED_BLOCK:
2240 : break;
2241 0 : default:
2242 0 : goto illegal;
2243 : }
2244 : break;
2245 :
2246 0 : case SDEV_RUNNING:
2247 0 : switch (oldstate) {
2248 : case SDEV_CREATED:
2249 : case SDEV_OFFLINE:
2250 : case SDEV_TRANSPORT_OFFLINE:
2251 : case SDEV_QUIESCE:
2252 : case SDEV_BLOCK:
2253 : break;
2254 0 : default:
2255 0 : goto illegal;
2256 : }
2257 : break;
2258 :
2259 0 : case SDEV_QUIESCE:
2260 0 : switch (oldstate) {
2261 : case SDEV_RUNNING:
2262 : case SDEV_OFFLINE:
2263 : case SDEV_TRANSPORT_OFFLINE:
2264 : break;
2265 0 : default:
2266 0 : goto illegal;
2267 : }
2268 : break;
2269 :
2270 0 : case SDEV_OFFLINE:
2271 : case SDEV_TRANSPORT_OFFLINE:
2272 0 : switch (oldstate) {
2273 : case SDEV_CREATED:
2274 : case SDEV_RUNNING:
2275 : case SDEV_QUIESCE:
2276 : case SDEV_BLOCK:
2277 : break;
2278 0 : default:
2279 0 : goto illegal;
2280 : }
2281 : break;
2282 :
2283 0 : case SDEV_BLOCK:
2284 0 : switch (oldstate) {
2285 : case SDEV_RUNNING:
2286 : case SDEV_CREATED_BLOCK:
2287 : case SDEV_QUIESCE:
2288 : case SDEV_OFFLINE:
2289 : break;
2290 0 : default:
2291 0 : goto illegal;
2292 : }
2293 : break;
2294 :
2295 0 : case SDEV_CREATED_BLOCK:
2296 0 : switch (oldstate) {
2297 : case SDEV_CREATED:
2298 : break;
2299 0 : default:
2300 0 : goto illegal;
2301 : }
2302 : break;
2303 :
2304 0 : case SDEV_CANCEL:
2305 0 : switch (oldstate) {
2306 : case SDEV_CREATED:
2307 : case SDEV_RUNNING:
2308 : case SDEV_QUIESCE:
2309 : case SDEV_OFFLINE:
2310 : case SDEV_TRANSPORT_OFFLINE:
2311 : break;
2312 0 : default:
2313 0 : goto illegal;
2314 : }
2315 : break;
2316 :
2317 0 : case SDEV_DEL:
2318 0 : switch (oldstate) {
2319 : case SDEV_CREATED:
2320 : case SDEV_RUNNING:
2321 : case SDEV_OFFLINE:
2322 : case SDEV_TRANSPORT_OFFLINE:
2323 : case SDEV_CANCEL:
2324 : case SDEV_BLOCK:
2325 : case SDEV_CREATED_BLOCK:
2326 : break;
2327 0 : default:
2328 0 : goto illegal;
2329 : }
2330 : break;
2331 :
2332 : }
2333 0 : sdev->offline_already = false;
2334 0 : sdev->sdev_state = state;
2335 0 : return 0;
2336 :
2337 0 : illegal:
2338 : SCSI_LOG_ERROR_RECOVERY(1,
2339 : sdev_printk(KERN_ERR, sdev,
2340 : "Illegal state transition %s->%s",
2341 : scsi_device_state_name(oldstate),
2342 : scsi_device_state_name(state))
2343 : );
2344 : return -EINVAL;
2345 : }
2346 : EXPORT_SYMBOL(scsi_device_set_state);
2347 :
2348 : /**
2349 : * scsi_evt_emit - emit a single SCSI device uevent
2350 : * @sdev: associated SCSI device
2351 : * @evt: event to emit
2352 : *
2353 : * Send a single uevent (scsi_event) to the associated scsi_device.
2354 : */
2355 0 : static void scsi_evt_emit(struct scsi_device *sdev, struct scsi_event *evt)
2356 : {
2357 0 : int idx = 0;
2358 0 : char *envp[3];
2359 :
2360 0 : switch (evt->evt_type) {
2361 0 : case SDEV_EVT_MEDIA_CHANGE:
2362 0 : envp[idx++] = "SDEV_MEDIA_CHANGE=1";
2363 0 : break;
2364 0 : case SDEV_EVT_INQUIRY_CHANGE_REPORTED:
2365 0 : scsi_rescan_device(&sdev->sdev_gendev);
2366 0 : envp[idx++] = "SDEV_UA=INQUIRY_DATA_HAS_CHANGED";
2367 0 : break;
2368 0 : case SDEV_EVT_CAPACITY_CHANGE_REPORTED:
2369 0 : envp[idx++] = "SDEV_UA=CAPACITY_DATA_HAS_CHANGED";
2370 0 : break;
2371 0 : case SDEV_EVT_SOFT_THRESHOLD_REACHED_REPORTED:
2372 0 : envp[idx++] = "SDEV_UA=THIN_PROVISIONING_SOFT_THRESHOLD_REACHED";
2373 0 : break;
2374 0 : case SDEV_EVT_MODE_PARAMETER_CHANGE_REPORTED:
2375 0 : envp[idx++] = "SDEV_UA=MODE_PARAMETERS_CHANGED";
2376 0 : break;
2377 0 : case SDEV_EVT_LUN_CHANGE_REPORTED:
2378 0 : envp[idx++] = "SDEV_UA=REPORTED_LUNS_DATA_HAS_CHANGED";
2379 0 : break;
2380 0 : case SDEV_EVT_ALUA_STATE_CHANGE_REPORTED:
2381 0 : envp[idx++] = "SDEV_UA=ASYMMETRIC_ACCESS_STATE_CHANGED";
2382 0 : break;
2383 0 : case SDEV_EVT_POWER_ON_RESET_OCCURRED:
2384 0 : envp[idx++] = "SDEV_UA=POWER_ON_RESET_OCCURRED";
2385 0 : break;
2386 : default:
2387 : /* do nothing */
2388 : break;
2389 : }
2390 :
2391 0 : envp[idx++] = NULL;
2392 :
2393 0 : kobject_uevent_env(&sdev->sdev_gendev.kobj, KOBJ_CHANGE, envp);
2394 0 : }
2395 :
2396 : /**
2397 : * scsi_evt_thread - send a uevent for each scsi event
2398 : * @work: work struct for scsi_device
2399 : *
2400 : * Dispatch queued events to their associated scsi_device kobjects
2401 : * as uevents.
2402 : */
2403 0 : void scsi_evt_thread(struct work_struct *work)
2404 : {
2405 0 : struct scsi_device *sdev;
2406 0 : enum scsi_device_event evt_type;
2407 0 : LIST_HEAD(event_list);
2408 :
2409 0 : sdev = container_of(work, struct scsi_device, event_work);
2410 :
2411 0 : for (evt_type = SDEV_EVT_FIRST; evt_type <= SDEV_EVT_LAST; evt_type++)
2412 0 : if (test_and_clear_bit(evt_type, sdev->pending_events))
2413 0 : sdev_evt_send_simple(sdev, evt_type, GFP_KERNEL);
2414 :
2415 0 : while (1) {
2416 0 : struct scsi_event *evt;
2417 0 : struct list_head *this, *tmp;
2418 0 : unsigned long flags;
2419 :
2420 0 : spin_lock_irqsave(&sdev->list_lock, flags);
2421 0 : list_splice_init(&sdev->event_list, &event_list);
2422 0 : spin_unlock_irqrestore(&sdev->list_lock, flags);
2423 :
2424 0 : if (list_empty(&event_list))
2425 : break;
2426 :
2427 0 : list_for_each_safe(this, tmp, &event_list) {
2428 0 : evt = list_entry(this, struct scsi_event, node);
2429 0 : list_del(&evt->node);
2430 0 : scsi_evt_emit(sdev, evt);
2431 0 : kfree(evt);
2432 : }
2433 : }
2434 0 : }
2435 :
2436 : /**
2437 : * sdev_evt_send - send asserted event to uevent thread
2438 : * @sdev: scsi_device event occurred on
2439 : * @evt: event to send
2440 : *
2441 : * Assert scsi device event asynchronously.
2442 : */
2443 0 : void sdev_evt_send(struct scsi_device *sdev, struct scsi_event *evt)
2444 : {
2445 0 : unsigned long flags;
2446 :
2447 : #if 0
2448 : /* FIXME: currently this check eliminates all media change events
2449 : * for polled devices. Need to update to discriminate between AN
2450 : * and polled events */
2451 : if (!test_bit(evt->evt_type, sdev->supported_events)) {
2452 : kfree(evt);
2453 : return;
2454 : }
2455 : #endif
2456 :
2457 0 : spin_lock_irqsave(&sdev->list_lock, flags);
2458 0 : list_add_tail(&evt->node, &sdev->event_list);
2459 0 : schedule_work(&sdev->event_work);
2460 0 : spin_unlock_irqrestore(&sdev->list_lock, flags);
2461 0 : }
2462 : EXPORT_SYMBOL_GPL(sdev_evt_send);
2463 :
2464 : /**
2465 : * sdev_evt_alloc - allocate a new scsi event
2466 : * @evt_type: type of event to allocate
2467 : * @gfpflags: GFP flags for allocation
2468 : *
2469 : * Allocates and returns a new scsi_event.
2470 : */
2471 0 : struct scsi_event *sdev_evt_alloc(enum scsi_device_event evt_type,
2472 : gfp_t gfpflags)
2473 : {
2474 0 : struct scsi_event *evt = kzalloc(sizeof(struct scsi_event), gfpflags);
2475 0 : if (!evt)
2476 : return NULL;
2477 :
2478 0 : evt->evt_type = evt_type;
2479 0 : INIT_LIST_HEAD(&evt->node);
2480 :
2481 : /* evt_type-specific initialization, if any */
2482 0 : switch (evt_type) {
2483 : case SDEV_EVT_MEDIA_CHANGE:
2484 : case SDEV_EVT_INQUIRY_CHANGE_REPORTED:
2485 : case SDEV_EVT_CAPACITY_CHANGE_REPORTED:
2486 : case SDEV_EVT_SOFT_THRESHOLD_REACHED_REPORTED:
2487 : case SDEV_EVT_MODE_PARAMETER_CHANGE_REPORTED:
2488 : case SDEV_EVT_LUN_CHANGE_REPORTED:
2489 : case SDEV_EVT_ALUA_STATE_CHANGE_REPORTED:
2490 : case SDEV_EVT_POWER_ON_RESET_OCCURRED:
2491 : default:
2492 : /* do nothing */
2493 0 : break;
2494 : }
2495 :
2496 0 : return evt;
2497 : }
2498 : EXPORT_SYMBOL_GPL(sdev_evt_alloc);
2499 :
2500 : /**
2501 : * sdev_evt_send_simple - send asserted event to uevent thread
2502 : * @sdev: scsi_device event occurred on
2503 : * @evt_type: type of event to send
2504 : * @gfpflags: GFP flags for allocation
2505 : *
2506 : * Assert scsi device event asynchronously, given an event type.
2507 : */
2508 0 : void sdev_evt_send_simple(struct scsi_device *sdev,
2509 : enum scsi_device_event evt_type, gfp_t gfpflags)
2510 : {
2511 0 : struct scsi_event *evt = sdev_evt_alloc(evt_type, gfpflags);
2512 0 : if (!evt) {
2513 0 : sdev_printk(KERN_ERR, sdev, "event %d eaten due to OOM\n",
2514 : evt_type);
2515 0 : return;
2516 : }
2517 :
2518 0 : sdev_evt_send(sdev, evt);
2519 : }
2520 : EXPORT_SYMBOL_GPL(sdev_evt_send_simple);
2521 :
2522 : /**
2523 : * scsi_device_quiesce - Block all commands except power management.
2524 : * @sdev: scsi device to quiesce.
2525 : *
2526 : * This works by trying to transition to the SDEV_QUIESCE state
2527 : * (which must be a legal transition). When the device is in this
2528 : * state, only power management requests will be accepted, all others will
2529 : * be deferred.
2530 : *
2531 : * Must be called with user context, may sleep.
2532 : *
2533 : * Returns zero if unsuccessful or an error if not.
2534 : */
2535 : int
2536 0 : scsi_device_quiesce(struct scsi_device *sdev)
2537 : {
2538 0 : struct request_queue *q = sdev->request_queue;
2539 0 : int err;
2540 :
2541 : /*
2542 : * It is allowed to call scsi_device_quiesce() multiple times from
2543 : * the same context but concurrent scsi_device_quiesce() calls are
2544 : * not allowed.
2545 : */
2546 0 : WARN_ON_ONCE(sdev->quiesced_by && sdev->quiesced_by != current);
2547 :
2548 0 : if (sdev->quiesced_by == current)
2549 : return 0;
2550 :
2551 0 : blk_set_pm_only(q);
2552 :
2553 0 : blk_mq_freeze_queue(q);
2554 : /*
2555 : * Ensure that the effect of blk_set_pm_only() will be visible
2556 : * for percpu_ref_tryget() callers that occur after the queue
2557 : * unfreeze even if the queue was already frozen before this function
2558 : * was called. See also https://lwn.net/Articles/573497/.
2559 : */
2560 0 : synchronize_rcu();
2561 0 : blk_mq_unfreeze_queue(q);
2562 :
2563 0 : mutex_lock(&sdev->state_mutex);
2564 0 : err = scsi_device_set_state(sdev, SDEV_QUIESCE);
2565 0 : if (err == 0)
2566 0 : sdev->quiesced_by = current;
2567 : else
2568 0 : blk_clear_pm_only(q);
2569 0 : mutex_unlock(&sdev->state_mutex);
2570 :
2571 0 : return err;
2572 : }
2573 : EXPORT_SYMBOL(scsi_device_quiesce);
2574 :
2575 : /**
2576 : * scsi_device_resume - Restart user issued commands to a quiesced device.
2577 : * @sdev: scsi device to resume.
2578 : *
2579 : * Moves the device from quiesced back to running and restarts the
2580 : * queues.
2581 : *
2582 : * Must be called with user context, may sleep.
2583 : */
2584 0 : void scsi_device_resume(struct scsi_device *sdev)
2585 : {
2586 : /* check if the device state was mutated prior to resume, and if
2587 : * so assume the state is being managed elsewhere (for example
2588 : * device deleted during suspend)
2589 : */
2590 0 : mutex_lock(&sdev->state_mutex);
2591 0 : if (sdev->sdev_state == SDEV_QUIESCE)
2592 0 : scsi_device_set_state(sdev, SDEV_RUNNING);
2593 0 : if (sdev->quiesced_by) {
2594 0 : sdev->quiesced_by = NULL;
2595 0 : blk_clear_pm_only(sdev->request_queue);
2596 : }
2597 0 : mutex_unlock(&sdev->state_mutex);
2598 0 : }
2599 : EXPORT_SYMBOL(scsi_device_resume);
2600 :
2601 : static void
2602 0 : device_quiesce_fn(struct scsi_device *sdev, void *data)
2603 : {
2604 0 : scsi_device_quiesce(sdev);
2605 0 : }
2606 :
2607 : void
2608 0 : scsi_target_quiesce(struct scsi_target *starget)
2609 : {
2610 0 : starget_for_each_device(starget, NULL, device_quiesce_fn);
2611 0 : }
2612 : EXPORT_SYMBOL(scsi_target_quiesce);
2613 :
2614 : static void
2615 0 : device_resume_fn(struct scsi_device *sdev, void *data)
2616 : {
2617 0 : scsi_device_resume(sdev);
2618 0 : }
2619 :
2620 : void
2621 0 : scsi_target_resume(struct scsi_target *starget)
2622 : {
2623 0 : starget_for_each_device(starget, NULL, device_resume_fn);
2624 0 : }
2625 : EXPORT_SYMBOL(scsi_target_resume);
2626 :
2627 : /**
2628 : * scsi_internal_device_block_nowait - try to transition to the SDEV_BLOCK state
2629 : * @sdev: device to block
2630 : *
2631 : * Pause SCSI command processing on the specified device. Does not sleep.
2632 : *
2633 : * Returns zero if successful or a negative error code upon failure.
2634 : *
2635 : * Notes:
2636 : * This routine transitions the device to the SDEV_BLOCK state (which must be
2637 : * a legal transition). When the device is in this state, command processing
2638 : * is paused until the device leaves the SDEV_BLOCK state. See also
2639 : * scsi_internal_device_unblock_nowait().
2640 : */
2641 0 : int scsi_internal_device_block_nowait(struct scsi_device *sdev)
2642 : {
2643 0 : struct request_queue *q = sdev->request_queue;
2644 0 : int err = 0;
2645 :
2646 0 : err = scsi_device_set_state(sdev, SDEV_BLOCK);
2647 0 : if (err) {
2648 0 : err = scsi_device_set_state(sdev, SDEV_CREATED_BLOCK);
2649 :
2650 0 : if (err)
2651 : return err;
2652 : }
2653 :
2654 : /*
2655 : * The device has transitioned to SDEV_BLOCK. Stop the
2656 : * block layer from calling the midlayer with this device's
2657 : * request queue.
2658 : */
2659 0 : blk_mq_quiesce_queue_nowait(q);
2660 0 : return 0;
2661 : }
2662 : EXPORT_SYMBOL_GPL(scsi_internal_device_block_nowait);
2663 :
2664 : /**
2665 : * scsi_internal_device_block - try to transition to the SDEV_BLOCK state
2666 : * @sdev: device to block
2667 : *
2668 : * Pause SCSI command processing on the specified device and wait until all
2669 : * ongoing scsi_request_fn() / scsi_queue_rq() calls have finished. May sleep.
2670 : *
2671 : * Returns zero if successful or a negative error code upon failure.
2672 : *
2673 : * Note:
2674 : * This routine transitions the device to the SDEV_BLOCK state (which must be
2675 : * a legal transition). When the device is in this state, command processing
2676 : * is paused until the device leaves the SDEV_BLOCK state. See also
2677 : * scsi_internal_device_unblock().
2678 : */
2679 0 : static int scsi_internal_device_block(struct scsi_device *sdev)
2680 : {
2681 0 : struct request_queue *q = sdev->request_queue;
2682 0 : int err;
2683 :
2684 0 : mutex_lock(&sdev->state_mutex);
2685 0 : err = scsi_internal_device_block_nowait(sdev);
2686 0 : if (err == 0)
2687 0 : blk_mq_quiesce_queue(q);
2688 0 : mutex_unlock(&sdev->state_mutex);
2689 :
2690 0 : return err;
2691 : }
2692 :
2693 0 : void scsi_start_queue(struct scsi_device *sdev)
2694 : {
2695 0 : struct request_queue *q = sdev->request_queue;
2696 :
2697 0 : blk_mq_unquiesce_queue(q);
2698 0 : }
2699 :
2700 : /**
2701 : * scsi_internal_device_unblock_nowait - resume a device after a block request
2702 : * @sdev: device to resume
2703 : * @new_state: state to set the device to after unblocking
2704 : *
2705 : * Restart the device queue for a previously suspended SCSI device. Does not
2706 : * sleep.
2707 : *
2708 : * Returns zero if successful or a negative error code upon failure.
2709 : *
2710 : * Notes:
2711 : * This routine transitions the device to the SDEV_RUNNING state or to one of
2712 : * the offline states (which must be a legal transition) allowing the midlayer
2713 : * to goose the queue for this device.
2714 : */
2715 0 : int scsi_internal_device_unblock_nowait(struct scsi_device *sdev,
2716 : enum scsi_device_state new_state)
2717 : {
2718 0 : switch (new_state) {
2719 : case SDEV_RUNNING:
2720 : case SDEV_TRANSPORT_OFFLINE:
2721 0 : break;
2722 : default:
2723 : return -EINVAL;
2724 : }
2725 :
2726 : /*
2727 : * Try to transition the scsi device to SDEV_RUNNING or one of the
2728 : * offlined states and goose the device queue if successful.
2729 : */
2730 0 : switch (sdev->sdev_state) {
2731 0 : case SDEV_BLOCK:
2732 : case SDEV_TRANSPORT_OFFLINE:
2733 0 : sdev->sdev_state = new_state;
2734 0 : break;
2735 0 : case SDEV_CREATED_BLOCK:
2736 0 : if (new_state == SDEV_TRANSPORT_OFFLINE ||
2737 : new_state == SDEV_OFFLINE)
2738 0 : sdev->sdev_state = new_state;
2739 : else
2740 0 : sdev->sdev_state = SDEV_CREATED;
2741 : break;
2742 : case SDEV_CANCEL:
2743 : case SDEV_OFFLINE:
2744 : break;
2745 : default:
2746 : return -EINVAL;
2747 : }
2748 0 : scsi_start_queue(sdev);
2749 :
2750 0 : return 0;
2751 : }
2752 : EXPORT_SYMBOL_GPL(scsi_internal_device_unblock_nowait);
2753 :
2754 : /**
2755 : * scsi_internal_device_unblock - resume a device after a block request
2756 : * @sdev: device to resume
2757 : * @new_state: state to set the device to after unblocking
2758 : *
2759 : * Restart the device queue for a previously suspended SCSI device. May sleep.
2760 : *
2761 : * Returns zero if successful or a negative error code upon failure.
2762 : *
2763 : * Notes:
2764 : * This routine transitions the device to the SDEV_RUNNING state or to one of
2765 : * the offline states (which must be a legal transition) allowing the midlayer
2766 : * to goose the queue for this device.
2767 : */
2768 0 : static int scsi_internal_device_unblock(struct scsi_device *sdev,
2769 : enum scsi_device_state new_state)
2770 : {
2771 0 : int ret;
2772 :
2773 0 : mutex_lock(&sdev->state_mutex);
2774 0 : ret = scsi_internal_device_unblock_nowait(sdev, new_state);
2775 0 : mutex_unlock(&sdev->state_mutex);
2776 :
2777 0 : return ret;
2778 : }
2779 :
2780 : static void
2781 0 : device_block(struct scsi_device *sdev, void *data)
2782 : {
2783 0 : int ret;
2784 :
2785 0 : ret = scsi_internal_device_block(sdev);
2786 :
2787 0 : WARN_ONCE(ret, "scsi_internal_device_block(%s) failed: ret = %d\n",
2788 : dev_name(&sdev->sdev_gendev), ret);
2789 0 : }
2790 :
2791 : static int
2792 0 : target_block(struct device *dev, void *data)
2793 : {
2794 0 : if (scsi_is_target_device(dev))
2795 0 : starget_for_each_device(to_scsi_target(dev), NULL,
2796 : device_block);
2797 0 : return 0;
2798 : }
2799 :
2800 : void
2801 0 : scsi_target_block(struct device *dev)
2802 : {
2803 0 : if (scsi_is_target_device(dev))
2804 0 : starget_for_each_device(to_scsi_target(dev), NULL,
2805 : device_block);
2806 : else
2807 0 : device_for_each_child(dev, NULL, target_block);
2808 0 : }
2809 : EXPORT_SYMBOL_GPL(scsi_target_block);
2810 :
2811 : static void
2812 0 : device_unblock(struct scsi_device *sdev, void *data)
2813 : {
2814 0 : scsi_internal_device_unblock(sdev, *(enum scsi_device_state *)data);
2815 0 : }
2816 :
2817 : static int
2818 0 : target_unblock(struct device *dev, void *data)
2819 : {
2820 0 : if (scsi_is_target_device(dev))
2821 0 : starget_for_each_device(to_scsi_target(dev), data,
2822 : device_unblock);
2823 0 : return 0;
2824 : }
2825 :
2826 : void
2827 0 : scsi_target_unblock(struct device *dev, enum scsi_device_state new_state)
2828 : {
2829 0 : if (scsi_is_target_device(dev))
2830 0 : starget_for_each_device(to_scsi_target(dev), &new_state,
2831 : device_unblock);
2832 : else
2833 0 : device_for_each_child(dev, &new_state, target_unblock);
2834 0 : }
2835 : EXPORT_SYMBOL_GPL(scsi_target_unblock);
2836 :
2837 : int
2838 0 : scsi_host_block(struct Scsi_Host *shost)
2839 : {
2840 0 : struct scsi_device *sdev;
2841 0 : int ret = 0;
2842 :
2843 : /*
2844 : * Call scsi_internal_device_block_nowait so we can avoid
2845 : * calling synchronize_rcu() for each LUN.
2846 : */
2847 0 : shost_for_each_device(sdev, shost) {
2848 0 : mutex_lock(&sdev->state_mutex);
2849 0 : ret = scsi_internal_device_block_nowait(sdev);
2850 0 : mutex_unlock(&sdev->state_mutex);
2851 0 : if (ret) {
2852 0 : scsi_device_put(sdev);
2853 0 : break;
2854 : }
2855 : }
2856 :
2857 : /*
2858 : * SCSI never enables blk-mq's BLK_MQ_F_BLOCKING flag so
2859 : * calling synchronize_rcu() once is enough.
2860 : */
2861 0 : WARN_ON_ONCE(shost->tag_set.flags & BLK_MQ_F_BLOCKING);
2862 :
2863 0 : if (!ret)
2864 0 : synchronize_rcu();
2865 :
2866 0 : return ret;
2867 : }
2868 : EXPORT_SYMBOL_GPL(scsi_host_block);
2869 :
2870 : int
2871 0 : scsi_host_unblock(struct Scsi_Host *shost, int new_state)
2872 : {
2873 0 : struct scsi_device *sdev;
2874 0 : int ret = 0;
2875 :
2876 0 : shost_for_each_device(sdev, shost) {
2877 0 : ret = scsi_internal_device_unblock(sdev, new_state);
2878 0 : if (ret) {
2879 0 : scsi_device_put(sdev);
2880 0 : break;
2881 : }
2882 : }
2883 0 : return ret;
2884 : }
2885 : EXPORT_SYMBOL_GPL(scsi_host_unblock);
2886 :
2887 : /**
2888 : * scsi_kmap_atomic_sg - find and atomically map an sg-elemnt
2889 : * @sgl: scatter-gather list
2890 : * @sg_count: number of segments in sg
2891 : * @offset: offset in bytes into sg, on return offset into the mapped area
2892 : * @len: bytes to map, on return number of bytes mapped
2893 : *
2894 : * Returns virtual address of the start of the mapped page
2895 : */
2896 0 : void *scsi_kmap_atomic_sg(struct scatterlist *sgl, int sg_count,
2897 : size_t *offset, size_t *len)
2898 : {
2899 0 : int i;
2900 0 : size_t sg_len = 0, len_complete = 0;
2901 0 : struct scatterlist *sg;
2902 0 : struct page *page;
2903 :
2904 0 : WARN_ON(!irqs_disabled());
2905 :
2906 0 : for_each_sg(sgl, sg, sg_count, i) {
2907 0 : len_complete = sg_len; /* Complete sg-entries */
2908 0 : sg_len += sg->length;
2909 0 : if (sg_len > *offset)
2910 : break;
2911 : }
2912 :
2913 0 : if (unlikely(i == sg_count)) {
2914 0 : printk(KERN_ERR "%s: Bytes in sg: %zu, requested offset %zu, "
2915 : "elements %d\n",
2916 : __func__, sg_len, *offset, sg_count);
2917 0 : WARN_ON(1);
2918 0 : return NULL;
2919 : }
2920 :
2921 : /* Offset starting from the beginning of first page in this sg-entry */
2922 0 : *offset = *offset - len_complete + sg->offset;
2923 :
2924 : /* Assumption: contiguous pages can be accessed as "page + i" */
2925 0 : page = nth_page(sg_page(sg), (*offset >> PAGE_SHIFT));
2926 0 : *offset &= ~PAGE_MASK;
2927 :
2928 : /* Bytes in this sg-entry from *offset to the end of the page */
2929 0 : sg_len = PAGE_SIZE - *offset;
2930 0 : if (*len > sg_len)
2931 0 : *len = sg_len;
2932 :
2933 0 : return kmap_atomic(page);
2934 : }
2935 : EXPORT_SYMBOL(scsi_kmap_atomic_sg);
2936 :
2937 : /**
2938 : * scsi_kunmap_atomic_sg - atomically unmap a virtual address, previously mapped with scsi_kmap_atomic_sg
2939 : * @virt: virtual address to be unmapped
2940 : */
2941 0 : void scsi_kunmap_atomic_sg(void *virt)
2942 : {
2943 0 : kunmap_atomic(virt);
2944 0 : }
2945 : EXPORT_SYMBOL(scsi_kunmap_atomic_sg);
2946 :
2947 0 : void sdev_disable_disk_events(struct scsi_device *sdev)
2948 : {
2949 0 : atomic_inc(&sdev->disk_events_disable_depth);
2950 0 : }
2951 : EXPORT_SYMBOL(sdev_disable_disk_events);
2952 :
2953 0 : void sdev_enable_disk_events(struct scsi_device *sdev)
2954 : {
2955 0 : if (WARN_ON_ONCE(atomic_read(&sdev->disk_events_disable_depth) <= 0))
2956 : return;
2957 0 : atomic_dec(&sdev->disk_events_disable_depth);
2958 : }
2959 : EXPORT_SYMBOL(sdev_enable_disk_events);
2960 :
2961 0 : static unsigned char designator_prio(const unsigned char *d)
2962 : {
2963 0 : if (d[1] & 0x30)
2964 : /* not associated with LUN */
2965 : return 0;
2966 :
2967 0 : if (d[3] == 0)
2968 : /* invalid length */
2969 : return 0;
2970 :
2971 : /*
2972 : * Order of preference for lun descriptor:
2973 : * - SCSI name string
2974 : * - NAA IEEE Registered Extended
2975 : * - EUI-64 based 16-byte
2976 : * - EUI-64 based 12-byte
2977 : * - NAA IEEE Registered
2978 : * - NAA IEEE Extended
2979 : * - EUI-64 based 8-byte
2980 : * - SCSI name string (truncated)
2981 : * - T10 Vendor ID
2982 : * as longer descriptors reduce the likelyhood
2983 : * of identification clashes.
2984 : */
2985 :
2986 0 : switch (d[1] & 0xf) {
2987 : case 8:
2988 : /* SCSI name string, variable-length UTF-8 */
2989 : return 9;
2990 0 : case 3:
2991 0 : switch (d[4] >> 4) {
2992 : case 6:
2993 : /* NAA registered extended */
2994 : return 8;
2995 : case 5:
2996 : /* NAA registered */
2997 : return 5;
2998 : case 4:
2999 : /* NAA extended */
3000 : return 4;
3001 : case 3:
3002 : /* NAA locally assigned */
3003 : return 1;
3004 : default:
3005 : break;
3006 : }
3007 : break;
3008 0 : case 2:
3009 0 : switch (d[3]) {
3010 : case 16:
3011 : /* EUI64-based, 16 byte */
3012 : return 7;
3013 0 : case 12:
3014 : /* EUI64-based, 12 byte */
3015 0 : return 6;
3016 0 : case 8:
3017 : /* EUI64-based, 8 byte */
3018 0 : return 3;
3019 : default:
3020 : break;
3021 : }
3022 : break;
3023 0 : case 1:
3024 : /* T10 vendor ID */
3025 0 : return 1;
3026 : default:
3027 : break;
3028 : }
3029 :
3030 0 : return 0;
3031 : }
3032 :
3033 : /**
3034 : * scsi_vpd_lun_id - return a unique device identification
3035 : * @sdev: SCSI device
3036 : * @id: buffer for the identification
3037 : * @id_len: length of the buffer
3038 : *
3039 : * Copies a unique device identification into @id based
3040 : * on the information in the VPD page 0x83 of the device.
3041 : * The string will be formatted as a SCSI name string.
3042 : *
3043 : * Returns the length of the identification or error on failure.
3044 : * If the identifier is longer than the supplied buffer the actual
3045 : * identifier length is returned and the buffer is not zero-padded.
3046 : */
3047 0 : int scsi_vpd_lun_id(struct scsi_device *sdev, char *id, size_t id_len)
3048 : {
3049 0 : u8 cur_id_prio = 0;
3050 0 : u8 cur_id_size = 0;
3051 0 : const unsigned char *d, *cur_id_str;
3052 0 : const struct scsi_vpd *vpd_pg83;
3053 0 : int id_size = -EINVAL;
3054 :
3055 0 : rcu_read_lock();
3056 0 : vpd_pg83 = rcu_dereference(sdev->vpd_pg83);
3057 0 : if (!vpd_pg83) {
3058 0 : rcu_read_unlock();
3059 0 : return -ENXIO;
3060 : }
3061 :
3062 : /* The id string must be at least 20 bytes + terminating NULL byte */
3063 0 : if (id_len < 21) {
3064 0 : rcu_read_unlock();
3065 0 : return -EINVAL;
3066 : }
3067 :
3068 0 : memset(id, 0, id_len);
3069 0 : for (d = vpd_pg83->data + 4;
3070 0 : d < vpd_pg83->data + vpd_pg83->len;
3071 0 : d += d[3] + 4) {
3072 0 : u8 prio = designator_prio(d);
3073 :
3074 0 : if (prio == 0 || cur_id_prio > prio)
3075 0 : continue;
3076 :
3077 0 : switch (d[1] & 0xf) {
3078 0 : case 0x1:
3079 : /* T10 Vendor ID */
3080 0 : if (cur_id_size > d[3])
3081 : break;
3082 0 : cur_id_prio = prio;
3083 0 : cur_id_size = d[3];
3084 0 : if (cur_id_size + 4 > id_len)
3085 0 : cur_id_size = id_len - 4;
3086 0 : cur_id_str = d + 4;
3087 0 : id_size = snprintf(id, id_len, "t10.%*pE",
3088 : cur_id_size, cur_id_str);
3089 0 : break;
3090 0 : case 0x2:
3091 : /* EUI-64 */
3092 0 : cur_id_prio = prio;
3093 0 : cur_id_size = d[3];
3094 0 : cur_id_str = d + 4;
3095 0 : switch (cur_id_size) {
3096 0 : case 8:
3097 0 : id_size = snprintf(id, id_len,
3098 : "eui.%8phN",
3099 : cur_id_str);
3100 0 : break;
3101 0 : case 12:
3102 0 : id_size = snprintf(id, id_len,
3103 : "eui.%12phN",
3104 : cur_id_str);
3105 0 : break;
3106 0 : case 16:
3107 0 : id_size = snprintf(id, id_len,
3108 : "eui.%16phN",
3109 : cur_id_str);
3110 0 : break;
3111 : default:
3112 : break;
3113 : }
3114 : break;
3115 0 : case 0x3:
3116 : /* NAA */
3117 0 : cur_id_prio = prio;
3118 0 : cur_id_size = d[3];
3119 0 : cur_id_str = d + 4;
3120 0 : switch (cur_id_size) {
3121 0 : case 8:
3122 0 : id_size = snprintf(id, id_len,
3123 : "naa.%8phN",
3124 : cur_id_str);
3125 0 : break;
3126 0 : case 16:
3127 0 : id_size = snprintf(id, id_len,
3128 : "naa.%16phN",
3129 : cur_id_str);
3130 0 : break;
3131 : default:
3132 : break;
3133 : }
3134 : break;
3135 0 : case 0x8:
3136 : /* SCSI name string */
3137 0 : if (cur_id_size > d[3])
3138 : break;
3139 : /* Prefer others for truncated descriptor */
3140 0 : if (d[3] > id_len) {
3141 0 : prio = 2;
3142 0 : if (cur_id_prio > prio)
3143 : break;
3144 : }
3145 0 : cur_id_prio = prio;
3146 0 : cur_id_size = id_size = d[3];
3147 0 : cur_id_str = d + 4;
3148 0 : if (cur_id_size >= id_len)
3149 0 : cur_id_size = id_len - 1;
3150 0 : memcpy(id, cur_id_str, cur_id_size);
3151 0 : break;
3152 : default:
3153 : break;
3154 : }
3155 0 : }
3156 0 : rcu_read_unlock();
3157 :
3158 0 : return id_size;
3159 : }
3160 : EXPORT_SYMBOL(scsi_vpd_lun_id);
3161 :
3162 : /*
3163 : * scsi_vpd_tpg_id - return a target port group identifier
3164 : * @sdev: SCSI device
3165 : *
3166 : * Returns the Target Port Group identifier from the information
3167 : * froom VPD page 0x83 of the device.
3168 : *
3169 : * Returns the identifier or error on failure.
3170 : */
3171 0 : int scsi_vpd_tpg_id(struct scsi_device *sdev, int *rel_id)
3172 : {
3173 0 : const unsigned char *d;
3174 0 : const struct scsi_vpd *vpd_pg83;
3175 0 : int group_id = -EAGAIN, rel_port = -1;
3176 :
3177 0 : rcu_read_lock();
3178 0 : vpd_pg83 = rcu_dereference(sdev->vpd_pg83);
3179 0 : if (!vpd_pg83) {
3180 0 : rcu_read_unlock();
3181 0 : return -ENXIO;
3182 : }
3183 :
3184 0 : d = vpd_pg83->data + 4;
3185 0 : while (d < vpd_pg83->data + vpd_pg83->len) {
3186 0 : switch (d[1] & 0xf) {
3187 0 : case 0x4:
3188 : /* Relative target port */
3189 0 : rel_port = get_unaligned_be16(&d[6]);
3190 0 : break;
3191 0 : case 0x5:
3192 : /* Target port group */
3193 0 : group_id = get_unaligned_be16(&d[6]);
3194 0 : break;
3195 : default:
3196 : break;
3197 : }
3198 0 : d += d[3] + 4;
3199 : }
3200 0 : rcu_read_unlock();
3201 :
3202 0 : if (group_id >= 0 && rel_id && rel_port != -1)
3203 0 : *rel_id = rel_port;
3204 :
3205 : return group_id;
3206 : }
3207 : EXPORT_SYMBOL(scsi_vpd_tpg_id);
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