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1 | /* | |
2 | * scsi_lib.c Copyright (C) 1999 Eric Youngdale | |
3 | * | |
4 | * SCSI queueing library. | |
5 | * Initial versions: Eric Youngdale (eric@andante.org). | |
6 | * Based upon conversations with large numbers | |
7 | * of people at Linux Expo. | |
8 | */ | |
9 | ||
10 | #include <linux/bio.h> | |
11 | #include <linux/bitops.h> | |
12 | #include <linux/blkdev.h> | |
13 | #include <linux/completion.h> | |
14 | #include <linux/kernel.h> | |
15 | #include <linux/export.h> | |
16 | #include <linux/mempool.h> | |
17 | #include <linux/slab.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 | ||
24 | #include <scsi/scsi.h> | |
25 | #include <scsi/scsi_cmnd.h> | |
26 | #include <scsi/scsi_dbg.h> | |
27 | #include <scsi/scsi_device.h> | |
28 | #include <scsi/scsi_driver.h> | |
29 | #include <scsi/scsi_eh.h> | |
30 | #include <scsi/scsi_host.h> | |
31 | ||
32 | #include "scsi_priv.h" | |
33 | #include "scsi_logging.h" | |
34 | ||
35 | ||
36 | #define SG_MEMPOOL_NR ARRAY_SIZE(scsi_sg_pools) | |
37 | #define SG_MEMPOOL_SIZE 2 | |
38 | ||
39 | struct scsi_host_sg_pool { | |
40 | size_t size; | |
41 | char *name; | |
42 | struct kmem_cache *slab; | |
43 | mempool_t *pool; | |
44 | }; | |
45 | ||
46 | #define SP(x) { x, "sgpool-" __stringify(x) } | |
47 | #if (SCSI_MAX_SG_SEGMENTS < 32) | |
48 | #error SCSI_MAX_SG_SEGMENTS is too small (must be 32 or greater) | |
49 | #endif | |
50 | static struct scsi_host_sg_pool scsi_sg_pools[] = { | |
51 | SP(8), | |
52 | SP(16), | |
53 | #if (SCSI_MAX_SG_SEGMENTS > 32) | |
54 | SP(32), | |
55 | #if (SCSI_MAX_SG_SEGMENTS > 64) | |
56 | SP(64), | |
57 | #if (SCSI_MAX_SG_SEGMENTS > 128) | |
58 | SP(128), | |
59 | #if (SCSI_MAX_SG_SEGMENTS > 256) | |
60 | #error SCSI_MAX_SG_SEGMENTS is too large (256 MAX) | |
61 | #endif | |
62 | #endif | |
63 | #endif | |
64 | #endif | |
65 | SP(SCSI_MAX_SG_SEGMENTS) | |
66 | }; | |
67 | #undef SP | |
68 | ||
69 | struct kmem_cache *scsi_sdb_cache; | |
70 | ||
71 | /* | |
72 | * When to reinvoke queueing after a resource shortage. It's 3 msecs to | |
73 | * not change behaviour from the previous unplug mechanism, experimentation | |
74 | * may prove this needs changing. | |
75 | */ | |
76 | #define SCSI_QUEUE_DELAY 3 | |
77 | ||
78 | /* | |
79 | * Function: scsi_unprep_request() | |
80 | * | |
81 | * Purpose: Remove all preparation done for a request, including its | |
82 | * associated scsi_cmnd, so that it can be requeued. | |
83 | * | |
84 | * Arguments: req - request to unprepare | |
85 | * | |
86 | * Lock status: Assumed that no locks are held upon entry. | |
87 | * | |
88 | * Returns: Nothing. | |
89 | */ | |
90 | static void scsi_unprep_request(struct request *req) | |
91 | { | |
92 | struct scsi_cmnd *cmd = req->special; | |
93 | ||
94 | blk_unprep_request(req); | |
95 | req->special = NULL; | |
96 | ||
97 | scsi_put_command(cmd); | |
98 | } | |
99 | ||
100 | /** | |
101 | * __scsi_queue_insert - private queue insertion | |
102 | * @cmd: The SCSI command being requeued | |
103 | * @reason: The reason for the requeue | |
104 | * @unbusy: Whether the queue should be unbusied | |
105 | * | |
106 | * This is a private queue insertion. The public interface | |
107 | * scsi_queue_insert() always assumes the queue should be unbusied | |
108 | * because it's always called before the completion. This function is | |
109 | * for a requeue after completion, which should only occur in this | |
110 | * file. | |
111 | */ | |
112 | static int __scsi_queue_insert(struct scsi_cmnd *cmd, int reason, int unbusy) | |
113 | { | |
114 | struct Scsi_Host *host = cmd->device->host; | |
115 | struct scsi_device *device = cmd->device; | |
116 | struct scsi_target *starget = scsi_target(device); | |
117 | struct request_queue *q = device->request_queue; | |
118 | unsigned long flags; | |
119 | ||
120 | SCSI_LOG_MLQUEUE(1, | |
121 | printk("Inserting command %p into mlqueue\n", cmd)); | |
122 | ||
123 | /* | |
124 | * Set the appropriate busy bit for the device/host. | |
125 | * | |
126 | * If the host/device isn't busy, assume that something actually | |
127 | * completed, and that we should be able to queue a command now. | |
128 | * | |
129 | * Note that the prior mid-layer assumption that any host could | |
130 | * always queue at least one command is now broken. The mid-layer | |
131 | * will implement a user specifiable stall (see | |
132 | * scsi_host.max_host_blocked and scsi_device.max_device_blocked) | |
133 | * if a command is requeued with no other commands outstanding | |
134 | * either for the device or for the host. | |
135 | */ | |
136 | switch (reason) { | |
137 | case SCSI_MLQUEUE_HOST_BUSY: | |
138 | host->host_blocked = host->max_host_blocked; | |
139 | break; | |
140 | case SCSI_MLQUEUE_DEVICE_BUSY: | |
141 | case SCSI_MLQUEUE_EH_RETRY: | |
142 | device->device_blocked = device->max_device_blocked; | |
143 | break; | |
144 | case SCSI_MLQUEUE_TARGET_BUSY: | |
145 | starget->target_blocked = starget->max_target_blocked; | |
146 | break; | |
147 | } | |
148 | ||
149 | /* | |
150 | * Decrement the counters, since these commands are no longer | |
151 | * active on the host/device. | |
152 | */ | |
153 | if (unbusy) | |
154 | scsi_device_unbusy(device); | |
155 | ||
156 | /* | |
157 | * Requeue this command. It will go before all other commands | |
158 | * that are already in the queue. | |
159 | */ | |
160 | spin_lock_irqsave(q->queue_lock, flags); | |
161 | blk_requeue_request(q, cmd->request); | |
162 | spin_unlock_irqrestore(q->queue_lock, flags); | |
163 | ||
164 | kblockd_schedule_work(q, &device->requeue_work); | |
165 | ||
166 | return 0; | |
167 | } | |
168 | ||
169 | /* | |
170 | * Function: scsi_queue_insert() | |
171 | * | |
172 | * Purpose: Insert a command in the midlevel queue. | |
173 | * | |
174 | * Arguments: cmd - command that we are adding to queue. | |
175 | * reason - why we are inserting command to queue. | |
176 | * | |
177 | * Lock status: Assumed that lock is not held upon entry. | |
178 | * | |
179 | * Returns: Nothing. | |
180 | * | |
181 | * Notes: We do this for one of two cases. Either the host is busy | |
182 | * and it cannot accept any more commands for the time being, | |
183 | * or the device returned QUEUE_FULL and can accept no more | |
184 | * commands. | |
185 | * Notes: This could be called either from an interrupt context or a | |
186 | * normal process context. | |
187 | */ | |
188 | int scsi_queue_insert(struct scsi_cmnd *cmd, int reason) | |
189 | { | |
190 | return __scsi_queue_insert(cmd, reason, 1); | |
191 | } | |
192 | /** | |
193 | * scsi_execute - insert request and wait for the result | |
194 | * @sdev: scsi device | |
195 | * @cmd: scsi command | |
196 | * @data_direction: data direction | |
197 | * @buffer: data buffer | |
198 | * @bufflen: len of buffer | |
199 | * @sense: optional sense buffer | |
200 | * @timeout: request timeout in seconds | |
201 | * @retries: number of times to retry request | |
202 | * @flags: or into request flags; | |
203 | * @resid: optional residual length | |
204 | * | |
205 | * returns the req->errors value which is the scsi_cmnd result | |
206 | * field. | |
207 | */ | |
208 | int scsi_execute(struct scsi_device *sdev, const unsigned char *cmd, | |
209 | int data_direction, void *buffer, unsigned bufflen, | |
210 | unsigned char *sense, int timeout, int retries, int flags, | |
211 | int *resid) | |
212 | { | |
213 | struct request *req; | |
214 | int write = (data_direction == DMA_TO_DEVICE); | |
215 | int ret = DRIVER_ERROR << 24; | |
216 | ||
217 | req = blk_get_request(sdev->request_queue, write, __GFP_WAIT); | |
218 | if (!req) | |
219 | return ret; | |
220 | ||
221 | if (bufflen && blk_rq_map_kern(sdev->request_queue, req, | |
222 | buffer, bufflen, __GFP_WAIT)) | |
223 | goto out; | |
224 | ||
225 | req->cmd_len = COMMAND_SIZE(cmd[0]); | |
226 | memcpy(req->cmd, cmd, req->cmd_len); | |
227 | req->sense = sense; | |
228 | req->sense_len = 0; | |
229 | req->retries = retries; | |
230 | req->timeout = timeout; | |
231 | req->cmd_type = REQ_TYPE_BLOCK_PC; | |
232 | req->cmd_flags |= flags | REQ_QUIET | REQ_PREEMPT; | |
233 | ||
234 | /* | |
235 | * head injection *required* here otherwise quiesce won't work | |
236 | */ | |
237 | blk_execute_rq(req->q, NULL, req, 1); | |
238 | ||
239 | /* | |
240 | * Some devices (USB mass-storage in particular) may transfer | |
241 | * garbage data together with a residue indicating that the data | |
242 | * is invalid. Prevent the garbage from being misinterpreted | |
243 | * and prevent security leaks by zeroing out the excess data. | |
244 | */ | |
245 | if (unlikely(req->resid_len > 0 && req->resid_len <= bufflen)) | |
246 | memset(buffer + (bufflen - req->resid_len), 0, req->resid_len); | |
247 | ||
248 | if (resid) | |
249 | *resid = req->resid_len; | |
250 | ret = req->errors; | |
251 | out: | |
252 | blk_put_request(req); | |
253 | ||
254 | return ret; | |
255 | } | |
256 | EXPORT_SYMBOL(scsi_execute); | |
257 | ||
258 | ||
259 | int scsi_execute_req(struct scsi_device *sdev, const unsigned char *cmd, | |
260 | int data_direction, void *buffer, unsigned bufflen, | |
261 | struct scsi_sense_hdr *sshdr, int timeout, int retries, | |
262 | int *resid) | |
263 | { | |
264 | char *sense = NULL; | |
265 | int result; | |
266 | ||
267 | if (sshdr) { | |
268 | sense = kzalloc(SCSI_SENSE_BUFFERSIZE, GFP_NOIO); | |
269 | if (!sense) | |
270 | return DRIVER_ERROR << 24; | |
271 | } | |
272 | result = scsi_execute(sdev, cmd, data_direction, buffer, bufflen, | |
273 | sense, timeout, retries, 0, resid); | |
274 | if (sshdr) | |
275 | scsi_normalize_sense(sense, SCSI_SENSE_BUFFERSIZE, sshdr); | |
276 | ||
277 | kfree(sense); | |
278 | return result; | |
279 | } | |
280 | EXPORT_SYMBOL(scsi_execute_req); | |
281 | ||
282 | /* | |
283 | * Function: scsi_init_cmd_errh() | |
284 | * | |
285 | * Purpose: Initialize cmd fields related to error handling. | |
286 | * | |
287 | * Arguments: cmd - command that is ready to be queued. | |
288 | * | |
289 | * Notes: This function has the job of initializing a number of | |
290 | * fields related to error handling. Typically this will | |
291 | * be called once for each command, as required. | |
292 | */ | |
293 | static void scsi_init_cmd_errh(struct scsi_cmnd *cmd) | |
294 | { | |
295 | cmd->serial_number = 0; | |
296 | scsi_set_resid(cmd, 0); | |
297 | memset(cmd->sense_buffer, 0, SCSI_SENSE_BUFFERSIZE); | |
298 | if (cmd->cmd_len == 0) | |
299 | cmd->cmd_len = scsi_command_size(cmd->cmnd); | |
300 | } | |
301 | ||
302 | void scsi_device_unbusy(struct scsi_device *sdev) | |
303 | { | |
304 | struct Scsi_Host *shost = sdev->host; | |
305 | struct scsi_target *starget = scsi_target(sdev); | |
306 | unsigned long flags; | |
307 | ||
308 | spin_lock_irqsave(shost->host_lock, flags); | |
309 | shost->host_busy--; | |
310 | starget->target_busy--; | |
311 | if (unlikely(scsi_host_in_recovery(shost) && | |
312 | (shost->host_failed || shost->host_eh_scheduled))) | |
313 | scsi_eh_wakeup(shost); | |
314 | spin_unlock(shost->host_lock); | |
315 | spin_lock(sdev->request_queue->queue_lock); | |
316 | sdev->device_busy--; | |
317 | spin_unlock_irqrestore(sdev->request_queue->queue_lock, flags); | |
318 | } | |
319 | ||
320 | /* | |
321 | * Called for single_lun devices on IO completion. Clear starget_sdev_user, | |
322 | * and call blk_run_queue for all the scsi_devices on the target - | |
323 | * including current_sdev first. | |
324 | * | |
325 | * Called with *no* scsi locks held. | |
326 | */ | |
327 | static void scsi_single_lun_run(struct scsi_device *current_sdev) | |
328 | { | |
329 | struct Scsi_Host *shost = current_sdev->host; | |
330 | struct scsi_device *sdev, *tmp; | |
331 | struct scsi_target *starget = scsi_target(current_sdev); | |
332 | unsigned long flags; | |
333 | ||
334 | spin_lock_irqsave(shost->host_lock, flags); | |
335 | starget->starget_sdev_user = NULL; | |
336 | spin_unlock_irqrestore(shost->host_lock, flags); | |
337 | ||
338 | /* | |
339 | * Call blk_run_queue for all LUNs on the target, starting with | |
340 | * current_sdev. We race with others (to set starget_sdev_user), | |
341 | * but in most cases, we will be first. Ideally, each LU on the | |
342 | * target would get some limited time or requests on the target. | |
343 | */ | |
344 | blk_run_queue(current_sdev->request_queue); | |
345 | ||
346 | spin_lock_irqsave(shost->host_lock, flags); | |
347 | if (starget->starget_sdev_user) | |
348 | goto out; | |
349 | list_for_each_entry_safe(sdev, tmp, &starget->devices, | |
350 | same_target_siblings) { | |
351 | if (sdev == current_sdev) | |
352 | continue; | |
353 | if (scsi_device_get(sdev)) | |
354 | continue; | |
355 | ||
356 | spin_unlock_irqrestore(shost->host_lock, flags); | |
357 | blk_run_queue(sdev->request_queue); | |
358 | spin_lock_irqsave(shost->host_lock, flags); | |
359 | ||
360 | scsi_device_put(sdev); | |
361 | } | |
362 | out: | |
363 | spin_unlock_irqrestore(shost->host_lock, flags); | |
364 | } | |
365 | ||
366 | static inline int scsi_device_is_busy(struct scsi_device *sdev) | |
367 | { | |
368 | if (sdev->device_busy >= sdev->queue_depth || sdev->device_blocked) | |
369 | return 1; | |
370 | ||
371 | return 0; | |
372 | } | |
373 | ||
374 | static inline int scsi_target_is_busy(struct scsi_target *starget) | |
375 | { | |
376 | return ((starget->can_queue > 0 && | |
377 | starget->target_busy >= starget->can_queue) || | |
378 | starget->target_blocked); | |
379 | } | |
380 | ||
381 | static inline int scsi_host_is_busy(struct Scsi_Host *shost) | |
382 | { | |
383 | if ((shost->can_queue > 0 && shost->host_busy >= shost->can_queue) || | |
384 | shost->host_blocked || shost->host_self_blocked) | |
385 | return 1; | |
386 | ||
387 | return 0; | |
388 | } | |
389 | ||
390 | /* | |
391 | * Function: scsi_run_queue() | |
392 | * | |
393 | * Purpose: Select a proper request queue to serve next | |
394 | * | |
395 | * Arguments: q - last request's queue | |
396 | * | |
397 | * Returns: Nothing | |
398 | * | |
399 | * Notes: The previous command was completely finished, start | |
400 | * a new one if possible. | |
401 | */ | |
402 | static void scsi_run_queue(struct request_queue *q) | |
403 | { | |
404 | struct scsi_device *sdev = q->queuedata; | |
405 | struct Scsi_Host *shost; | |
406 | LIST_HEAD(starved_list); | |
407 | unsigned long flags; | |
408 | ||
409 | /* if the device is dead, sdev will be NULL, so no queue to run */ | |
410 | if (!sdev) | |
411 | return; | |
412 | ||
413 | shost = sdev->host; | |
414 | if (scsi_target(sdev)->single_lun) | |
415 | scsi_single_lun_run(sdev); | |
416 | ||
417 | spin_lock_irqsave(shost->host_lock, flags); | |
418 | list_splice_init(&shost->starved_list, &starved_list); | |
419 | ||
420 | while (!list_empty(&starved_list)) { | |
421 | /* | |
422 | * As long as shost is accepting commands and we have | |
423 | * starved queues, call blk_run_queue. scsi_request_fn | |
424 | * drops the queue_lock and can add us back to the | |
425 | * starved_list. | |
426 | * | |
427 | * host_lock protects the starved_list and starved_entry. | |
428 | * scsi_request_fn must get the host_lock before checking | |
429 | * or modifying starved_list or starved_entry. | |
430 | */ | |
431 | if (scsi_host_is_busy(shost)) | |
432 | break; | |
433 | ||
434 | sdev = list_entry(starved_list.next, | |
435 | struct scsi_device, starved_entry); | |
436 | list_del_init(&sdev->starved_entry); | |
437 | if (scsi_target_is_busy(scsi_target(sdev))) { | |
438 | list_move_tail(&sdev->starved_entry, | |
439 | &shost->starved_list); | |
440 | continue; | |
441 | } | |
442 | ||
443 | spin_unlock(shost->host_lock); | |
444 | spin_lock(sdev->request_queue->queue_lock); | |
445 | __blk_run_queue(sdev->request_queue); | |
446 | spin_unlock(sdev->request_queue->queue_lock); | |
447 | spin_lock(shost->host_lock); | |
448 | } | |
449 | /* put any unprocessed entries back */ | |
450 | list_splice(&starved_list, &shost->starved_list); | |
451 | spin_unlock_irqrestore(shost->host_lock, flags); | |
452 | ||
453 | blk_run_queue(q); | |
454 | } | |
455 | ||
456 | void scsi_requeue_run_queue(struct work_struct *work) | |
457 | { | |
458 | struct scsi_device *sdev; | |
459 | struct request_queue *q; | |
460 | ||
461 | sdev = container_of(work, struct scsi_device, requeue_work); | |
462 | q = sdev->request_queue; | |
463 | scsi_run_queue(q); | |
464 | } | |
465 | ||
466 | /* | |
467 | * Function: scsi_requeue_command() | |
468 | * | |
469 | * Purpose: Handle post-processing of completed commands. | |
470 | * | |
471 | * Arguments: q - queue to operate on | |
472 | * cmd - command that may need to be requeued. | |
473 | * | |
474 | * Returns: Nothing | |
475 | * | |
476 | * Notes: After command completion, there may be blocks left | |
477 | * over which weren't finished by the previous command | |
478 | * this can be for a number of reasons - the main one is | |
479 | * I/O errors in the middle of the request, in which case | |
480 | * we need to request the blocks that come after the bad | |
481 | * sector. | |
482 | * Notes: Upon return, cmd is a stale pointer. | |
483 | */ | |
484 | static void scsi_requeue_command(struct request_queue *q, struct scsi_cmnd *cmd) | |
485 | { | |
486 | struct request *req = cmd->request; | |
487 | unsigned long flags; | |
488 | ||
489 | spin_lock_irqsave(q->queue_lock, flags); | |
490 | scsi_unprep_request(req); | |
491 | blk_requeue_request(q, req); | |
492 | spin_unlock_irqrestore(q->queue_lock, flags); | |
493 | ||
494 | scsi_run_queue(q); | |
495 | } | |
496 | ||
497 | void scsi_next_command(struct scsi_cmnd *cmd) | |
498 | { | |
499 | struct scsi_device *sdev = cmd->device; | |
500 | struct request_queue *q = sdev->request_queue; | |
501 | ||
502 | /* need to hold a reference on the device before we let go of the cmd */ | |
503 | get_device(&sdev->sdev_gendev); | |
504 | ||
505 | scsi_put_command(cmd); | |
506 | scsi_run_queue(q); | |
507 | ||
508 | /* ok to remove device now */ | |
509 | put_device(&sdev->sdev_gendev); | |
510 | } | |
511 | ||
512 | void scsi_run_host_queues(struct Scsi_Host *shost) | |
513 | { | |
514 | struct scsi_device *sdev; | |
515 | ||
516 | shost_for_each_device(sdev, shost) | |
517 | scsi_run_queue(sdev->request_queue); | |
518 | } | |
519 | ||
520 | static void __scsi_release_buffers(struct scsi_cmnd *, int); | |
521 | ||
522 | /* | |
523 | * Function: scsi_end_request() | |
524 | * | |
525 | * Purpose: Post-processing of completed commands (usually invoked at end | |
526 | * of upper level post-processing and scsi_io_completion). | |
527 | * | |
528 | * Arguments: cmd - command that is complete. | |
529 | * error - 0 if I/O indicates success, < 0 for I/O error. | |
530 | * bytes - number of bytes of completed I/O | |
531 | * requeue - indicates whether we should requeue leftovers. | |
532 | * | |
533 | * Lock status: Assumed that lock is not held upon entry. | |
534 | * | |
535 | * Returns: cmd if requeue required, NULL otherwise. | |
536 | * | |
537 | * Notes: This is called for block device requests in order to | |
538 | * mark some number of sectors as complete. | |
539 | * | |
540 | * We are guaranteeing that the request queue will be goosed | |
541 | * at some point during this call. | |
542 | * Notes: If cmd was requeued, upon return it will be a stale pointer. | |
543 | */ | |
544 | static struct scsi_cmnd *scsi_end_request(struct scsi_cmnd *cmd, int error, | |
545 | int bytes, int requeue) | |
546 | { | |
547 | struct request_queue *q = cmd->device->request_queue; | |
548 | struct request *req = cmd->request; | |
549 | ||
550 | /* | |
551 | * If there are blocks left over at the end, set up the command | |
552 | * to queue the remainder of them. | |
553 | */ | |
554 | if (blk_end_request(req, error, bytes)) { | |
555 | /* kill remainder if no retrys */ | |
556 | if (error && scsi_noretry_cmd(cmd)) | |
557 | blk_end_request_all(req, error); | |
558 | else { | |
559 | if (requeue) { | |
560 | /* | |
561 | * Bleah. Leftovers again. Stick the | |
562 | * leftovers in the front of the | |
563 | * queue, and goose the queue again. | |
564 | */ | |
565 | scsi_release_buffers(cmd); | |
566 | scsi_requeue_command(q, cmd); | |
567 | cmd = NULL; | |
568 | } | |
569 | return cmd; | |
570 | } | |
571 | } | |
572 | ||
573 | /* | |
574 | * This will goose the queue request function at the end, so we don't | |
575 | * need to worry about launching another command. | |
576 | */ | |
577 | __scsi_release_buffers(cmd, 0); | |
578 | scsi_next_command(cmd); | |
579 | return NULL; | |
580 | } | |
581 | ||
582 | static inline unsigned int scsi_sgtable_index(unsigned short nents) | |
583 | { | |
584 | unsigned int index; | |
585 | ||
586 | BUG_ON(nents > SCSI_MAX_SG_SEGMENTS); | |
587 | ||
588 | if (nents <= 8) | |
589 | index = 0; | |
590 | else | |
591 | index = get_count_order(nents) - 3; | |
592 | ||
593 | return index; | |
594 | } | |
595 | ||
596 | static void scsi_sg_free(struct scatterlist *sgl, unsigned int nents) | |
597 | { | |
598 | struct scsi_host_sg_pool *sgp; | |
599 | ||
600 | sgp = scsi_sg_pools + scsi_sgtable_index(nents); | |
601 | mempool_free(sgl, sgp->pool); | |
602 | } | |
603 | ||
604 | static struct scatterlist *scsi_sg_alloc(unsigned int nents, gfp_t gfp_mask) | |
605 | { | |
606 | struct scsi_host_sg_pool *sgp; | |
607 | ||
608 | sgp = scsi_sg_pools + scsi_sgtable_index(nents); | |
609 | return mempool_alloc(sgp->pool, gfp_mask); | |
610 | } | |
611 | ||
612 | static int scsi_alloc_sgtable(struct scsi_data_buffer *sdb, int nents, | |
613 | gfp_t gfp_mask) | |
614 | { | |
615 | int ret; | |
616 | ||
617 | BUG_ON(!nents); | |
618 | ||
619 | ret = __sg_alloc_table(&sdb->table, nents, SCSI_MAX_SG_SEGMENTS, | |
620 | gfp_mask, scsi_sg_alloc); | |
621 | if (unlikely(ret)) | |
622 | __sg_free_table(&sdb->table, SCSI_MAX_SG_SEGMENTS, | |
623 | scsi_sg_free); | |
624 | ||
625 | return ret; | |
626 | } | |
627 | ||
628 | static void scsi_free_sgtable(struct scsi_data_buffer *sdb) | |
629 | { | |
630 | __sg_free_table(&sdb->table, SCSI_MAX_SG_SEGMENTS, scsi_sg_free); | |
631 | } | |
632 | ||
633 | static void __scsi_release_buffers(struct scsi_cmnd *cmd, int do_bidi_check) | |
634 | { | |
635 | ||
636 | if (cmd->sdb.table.nents) | |
637 | scsi_free_sgtable(&cmd->sdb); | |
638 | ||
639 | memset(&cmd->sdb, 0, sizeof(cmd->sdb)); | |
640 | ||
641 | if (do_bidi_check && scsi_bidi_cmnd(cmd)) { | |
642 | struct scsi_data_buffer *bidi_sdb = | |
643 | cmd->request->next_rq->special; | |
644 | scsi_free_sgtable(bidi_sdb); | |
645 | kmem_cache_free(scsi_sdb_cache, bidi_sdb); | |
646 | cmd->request->next_rq->special = NULL; | |
647 | } | |
648 | ||
649 | if (scsi_prot_sg_count(cmd)) | |
650 | scsi_free_sgtable(cmd->prot_sdb); | |
651 | } | |
652 | ||
653 | /* | |
654 | * Function: scsi_release_buffers() | |
655 | * | |
656 | * Purpose: Completion processing for block device I/O requests. | |
657 | * | |
658 | * Arguments: cmd - command that we are bailing. | |
659 | * | |
660 | * Lock status: Assumed that no lock is held upon entry. | |
661 | * | |
662 | * Returns: Nothing | |
663 | * | |
664 | * Notes: In the event that an upper level driver rejects a | |
665 | * command, we must release resources allocated during | |
666 | * the __init_io() function. Primarily this would involve | |
667 | * the scatter-gather table, and potentially any bounce | |
668 | * buffers. | |
669 | */ | |
670 | void scsi_release_buffers(struct scsi_cmnd *cmd) | |
671 | { | |
672 | __scsi_release_buffers(cmd, 1); | |
673 | } | |
674 | EXPORT_SYMBOL(scsi_release_buffers); | |
675 | ||
676 | static int __scsi_error_from_host_byte(struct scsi_cmnd *cmd, int result) | |
677 | { | |
678 | int error = 0; | |
679 | ||
680 | switch(host_byte(result)) { | |
681 | case DID_TRANSPORT_FAILFAST: | |
682 | error = -ENOLINK; | |
683 | break; | |
684 | case DID_TARGET_FAILURE: | |
685 | set_host_byte(cmd, DID_OK); | |
686 | error = -EREMOTEIO; | |
687 | break; | |
688 | case DID_NEXUS_FAILURE: | |
689 | set_host_byte(cmd, DID_OK); | |
690 | error = -EBADE; | |
691 | break; | |
692 | default: | |
693 | error = -EIO; | |
694 | break; | |
695 | } | |
696 | ||
697 | return error; | |
698 | } | |
699 | ||
700 | /* | |
701 | * Function: scsi_io_completion() | |
702 | * | |
703 | * Purpose: Completion processing for block device I/O requests. | |
704 | * | |
705 | * Arguments: cmd - command that is finished. | |
706 | * | |
707 | * Lock status: Assumed that no lock is held upon entry. | |
708 | * | |
709 | * Returns: Nothing | |
710 | * | |
711 | * Notes: This function is matched in terms of capabilities to | |
712 | * the function that created the scatter-gather list. | |
713 | * In other words, if there are no bounce buffers | |
714 | * (the normal case for most drivers), we don't need | |
715 | * the logic to deal with cleaning up afterwards. | |
716 | * | |
717 | * We must call scsi_end_request(). This will finish off | |
718 | * the specified number of sectors. If we are done, the | |
719 | * command block will be released and the queue function | |
720 | * will be goosed. If we are not done then we have to | |
721 | * figure out what to do next: | |
722 | * | |
723 | * a) We can call scsi_requeue_command(). The request | |
724 | * will be unprepared and put back on the queue. Then | |
725 | * a new command will be created for it. This should | |
726 | * be used if we made forward progress, or if we want | |
727 | * to switch from READ(10) to READ(6) for example. | |
728 | * | |
729 | * b) We can call scsi_queue_insert(). The request will | |
730 | * be put back on the queue and retried using the same | |
731 | * command as before, possibly after a delay. | |
732 | * | |
733 | * c) We can call blk_end_request() with -EIO to fail | |
734 | * the remainder of the request. | |
735 | */ | |
736 | void scsi_io_completion(struct scsi_cmnd *cmd, unsigned int good_bytes) | |
737 | { | |
738 | int result = cmd->result; | |
739 | struct request_queue *q = cmd->device->request_queue; | |
740 | struct request *req = cmd->request; | |
741 | int error = 0; | |
742 | struct scsi_sense_hdr sshdr; | |
743 | int sense_valid = 0; | |
744 | int sense_deferred = 0; | |
745 | enum {ACTION_FAIL, ACTION_REPREP, ACTION_RETRY, | |
746 | ACTION_DELAYED_RETRY} action; | |
747 | char *description = NULL; | |
748 | ||
749 | if (result) { | |
750 | sense_valid = scsi_command_normalize_sense(cmd, &sshdr); | |
751 | if (sense_valid) | |
752 | sense_deferred = scsi_sense_is_deferred(&sshdr); | |
753 | } | |
754 | ||
755 | if (req->cmd_type == REQ_TYPE_BLOCK_PC) { /* SG_IO ioctl from block level */ | |
756 | req->errors = result; | |
757 | if (result) { | |
758 | if (sense_valid && req->sense) { | |
759 | /* | |
760 | * SG_IO wants current and deferred errors | |
761 | */ | |
762 | int len = 8 + cmd->sense_buffer[7]; | |
763 | ||
764 | if (len > SCSI_SENSE_BUFFERSIZE) | |
765 | len = SCSI_SENSE_BUFFERSIZE; | |
766 | memcpy(req->sense, cmd->sense_buffer, len); | |
767 | req->sense_len = len; | |
768 | } | |
769 | if (!sense_deferred) | |
770 | error = __scsi_error_from_host_byte(cmd, result); | |
771 | } | |
772 | ||
773 | req->resid_len = scsi_get_resid(cmd); | |
774 | ||
775 | if (scsi_bidi_cmnd(cmd)) { | |
776 | /* | |
777 | * Bidi commands Must be complete as a whole, | |
778 | * both sides at once. | |
779 | */ | |
780 | req->next_rq->resid_len = scsi_in(cmd)->resid; | |
781 | ||
782 | scsi_release_buffers(cmd); | |
783 | blk_end_request_all(req, 0); | |
784 | ||
785 | scsi_next_command(cmd); | |
786 | return; | |
787 | } | |
788 | } | |
789 | ||
790 | /* no bidi support for !REQ_TYPE_BLOCK_PC yet */ | |
791 | BUG_ON(blk_bidi_rq(req)); | |
792 | ||
793 | /* | |
794 | * Next deal with any sectors which we were able to correctly | |
795 | * handle. | |
796 | */ | |
797 | SCSI_LOG_HLCOMPLETE(1, printk("%u sectors total, " | |
798 | "%d bytes done.\n", | |
799 | blk_rq_sectors(req), good_bytes)); | |
800 | ||
801 | /* | |
802 | * Recovered errors need reporting, but they're always treated | |
803 | * as success, so fiddle the result code here. For BLOCK_PC | |
804 | * we already took a copy of the original into rq->errors which | |
805 | * is what gets returned to the user | |
806 | */ | |
807 | if (sense_valid && (sshdr.sense_key == RECOVERED_ERROR)) { | |
808 | /* if ATA PASS-THROUGH INFORMATION AVAILABLE skip | |
809 | * print since caller wants ATA registers. Only occurs on | |
810 | * SCSI ATA PASS_THROUGH commands when CK_COND=1 | |
811 | */ | |
812 | if ((sshdr.asc == 0x0) && (sshdr.ascq == 0x1d)) | |
813 | ; | |
814 | else if (!(req->cmd_flags & REQ_QUIET)) | |
815 | scsi_print_sense("", cmd); | |
816 | result = 0; | |
817 | /* BLOCK_PC may have set error */ | |
818 | error = 0; | |
819 | } | |
820 | ||
821 | /* | |
822 | * A number of bytes were successfully read. If there | |
823 | * are leftovers and there is some kind of error | |
824 | * (result != 0), retry the rest. | |
825 | */ | |
826 | if (scsi_end_request(cmd, error, good_bytes, result == 0) == NULL) | |
827 | return; | |
828 | ||
829 | error = __scsi_error_from_host_byte(cmd, result); | |
830 | ||
831 | if (host_byte(result) == DID_RESET) { | |
832 | /* Third party bus reset or reset for error recovery | |
833 | * reasons. Just retry the command and see what | |
834 | * happens. | |
835 | */ | |
836 | action = ACTION_RETRY; | |
837 | } else if (sense_valid && !sense_deferred) { | |
838 | switch (sshdr.sense_key) { | |
839 | case UNIT_ATTENTION: | |
840 | if (cmd->device->removable) { | |
841 | /* Detected disc change. Set a bit | |
842 | * and quietly refuse further access. | |
843 | */ | |
844 | cmd->device->changed = 1; | |
845 | description = "Media Changed"; | |
846 | action = ACTION_FAIL; | |
847 | } else { | |
848 | /* Must have been a power glitch, or a | |
849 | * bus reset. Could not have been a | |
850 | * media change, so we just retry the | |
851 | * command and see what happens. | |
852 | */ | |
853 | action = ACTION_RETRY; | |
854 | } | |
855 | break; | |
856 | case ILLEGAL_REQUEST: | |
857 | /* If we had an ILLEGAL REQUEST returned, then | |
858 | * we may have performed an unsupported | |
859 | * command. The only thing this should be | |
860 | * would be a ten byte read where only a six | |
861 | * byte read was supported. Also, on a system | |
862 | * where READ CAPACITY failed, we may have | |
863 | * read past the end of the disk. | |
864 | */ | |
865 | if ((cmd->device->use_10_for_rw && | |
866 | sshdr.asc == 0x20 && sshdr.ascq == 0x00) && | |
867 | (cmd->cmnd[0] == READ_10 || | |
868 | cmd->cmnd[0] == WRITE_10)) { | |
869 | /* This will issue a new 6-byte command. */ | |
870 | cmd->device->use_10_for_rw = 0; | |
871 | action = ACTION_REPREP; | |
872 | } else if (sshdr.asc == 0x10) /* DIX */ { | |
873 | description = "Host Data Integrity Failure"; | |
874 | action = ACTION_FAIL; | |
875 | error = -EILSEQ; | |
876 | /* INVALID COMMAND OPCODE or INVALID FIELD IN CDB */ | |
877 | } else if ((sshdr.asc == 0x20 || sshdr.asc == 0x24) && | |
878 | (cmd->cmnd[0] == UNMAP || | |
879 | cmd->cmnd[0] == WRITE_SAME_16 || | |
880 | cmd->cmnd[0] == WRITE_SAME)) { | |
881 | description = "Discard failure"; | |
882 | action = ACTION_FAIL; | |
883 | error = -EREMOTEIO; | |
884 | } else | |
885 | action = ACTION_FAIL; | |
886 | break; | |
887 | case ABORTED_COMMAND: | |
888 | action = ACTION_FAIL; | |
889 | if (sshdr.asc == 0x10) { /* DIF */ | |
890 | description = "Target Data Integrity Failure"; | |
891 | error = -EILSEQ; | |
892 | } | |
893 | break; | |
894 | case NOT_READY: | |
895 | /* If the device is in the process of becoming | |
896 | * ready, or has a temporary blockage, retry. | |
897 | */ | |
898 | if (sshdr.asc == 0x04) { | |
899 | switch (sshdr.ascq) { | |
900 | case 0x01: /* becoming ready */ | |
901 | case 0x04: /* format in progress */ | |
902 | case 0x05: /* rebuild in progress */ | |
903 | case 0x06: /* recalculation in progress */ | |
904 | case 0x07: /* operation in progress */ | |
905 | case 0x08: /* Long write in progress */ | |
906 | case 0x09: /* self test in progress */ | |
907 | case 0x14: /* space allocation in progress */ | |
908 | action = ACTION_DELAYED_RETRY; | |
909 | break; | |
910 | default: | |
911 | description = "Device not ready"; | |
912 | action = ACTION_FAIL; | |
913 | break; | |
914 | } | |
915 | } else { | |
916 | description = "Device not ready"; | |
917 | action = ACTION_FAIL; | |
918 | } | |
919 | break; | |
920 | case VOLUME_OVERFLOW: | |
921 | /* See SSC3rXX or current. */ | |
922 | action = ACTION_FAIL; | |
923 | break; | |
924 | default: | |
925 | description = "Unhandled sense code"; | |
926 | action = ACTION_FAIL; | |
927 | break; | |
928 | } | |
929 | } else { | |
930 | description = "Unhandled error code"; | |
931 | action = ACTION_FAIL; | |
932 | } | |
933 | ||
934 | switch (action) { | |
935 | case ACTION_FAIL: | |
936 | /* Give up and fail the remainder of the request */ | |
937 | scsi_release_buffers(cmd); | |
938 | if (!(req->cmd_flags & REQ_QUIET)) { | |
939 | if (description) | |
940 | scmd_printk(KERN_INFO, cmd, "%s\n", | |
941 | description); | |
942 | scsi_print_result(cmd); | |
943 | if (driver_byte(result) & DRIVER_SENSE) | |
944 | scsi_print_sense("", cmd); | |
945 | scsi_print_command(cmd); | |
946 | } | |
947 | if (blk_end_request_err(req, error)) | |
948 | scsi_requeue_command(q, cmd); | |
949 | else | |
950 | scsi_next_command(cmd); | |
951 | break; | |
952 | case ACTION_REPREP: | |
953 | /* Unprep the request and put it back at the head of the queue. | |
954 | * A new command will be prepared and issued. | |
955 | */ | |
956 | scsi_release_buffers(cmd); | |
957 | scsi_requeue_command(q, cmd); | |
958 | break; | |
959 | case ACTION_RETRY: | |
960 | /* Retry the same command immediately */ | |
961 | __scsi_queue_insert(cmd, SCSI_MLQUEUE_EH_RETRY, 0); | |
962 | break; | |
963 | case ACTION_DELAYED_RETRY: | |
964 | /* Retry the same command after a delay */ | |
965 | __scsi_queue_insert(cmd, SCSI_MLQUEUE_DEVICE_BUSY, 0); | |
966 | break; | |
967 | } | |
968 | } | |
969 | ||
970 | static int scsi_init_sgtable(struct request *req, struct scsi_data_buffer *sdb, | |
971 | gfp_t gfp_mask) | |
972 | { | |
973 | int count; | |
974 | ||
975 | /* | |
976 | * If sg table allocation fails, requeue request later. | |
977 | */ | |
978 | if (unlikely(scsi_alloc_sgtable(sdb, req->nr_phys_segments, | |
979 | gfp_mask))) { | |
980 | return BLKPREP_DEFER; | |
981 | } | |
982 | ||
983 | req->buffer = NULL; | |
984 | ||
985 | /* | |
986 | * Next, walk the list, and fill in the addresses and sizes of | |
987 | * each segment. | |
988 | */ | |
989 | count = blk_rq_map_sg(req->q, req, sdb->table.sgl); | |
990 | BUG_ON(count > sdb->table.nents); | |
991 | sdb->table.nents = count; | |
992 | sdb->length = blk_rq_bytes(req); | |
993 | return BLKPREP_OK; | |
994 | } | |
995 | ||
996 | /* | |
997 | * Function: scsi_init_io() | |
998 | * | |
999 | * Purpose: SCSI I/O initialize function. | |
1000 | * | |
1001 | * Arguments: cmd - Command descriptor we wish to initialize | |
1002 | * | |
1003 | * Returns: 0 on success | |
1004 | * BLKPREP_DEFER if the failure is retryable | |
1005 | * BLKPREP_KILL if the failure is fatal | |
1006 | */ | |
1007 | int scsi_init_io(struct scsi_cmnd *cmd, gfp_t gfp_mask) | |
1008 | { | |
1009 | struct request *rq = cmd->request; | |
1010 | ||
1011 | int error = scsi_init_sgtable(rq, &cmd->sdb, gfp_mask); | |
1012 | if (error) | |
1013 | goto err_exit; | |
1014 | ||
1015 | if (blk_bidi_rq(rq)) { | |
1016 | struct scsi_data_buffer *bidi_sdb = kmem_cache_zalloc( | |
1017 | scsi_sdb_cache, GFP_ATOMIC); | |
1018 | if (!bidi_sdb) { | |
1019 | error = BLKPREP_DEFER; | |
1020 | goto err_exit; | |
1021 | } | |
1022 | ||
1023 | rq->next_rq->special = bidi_sdb; | |
1024 | error = scsi_init_sgtable(rq->next_rq, bidi_sdb, GFP_ATOMIC); | |
1025 | if (error) | |
1026 | goto err_exit; | |
1027 | } | |
1028 | ||
1029 | if (blk_integrity_rq(rq)) { | |
1030 | struct scsi_data_buffer *prot_sdb = cmd->prot_sdb; | |
1031 | int ivecs, count; | |
1032 | ||
1033 | BUG_ON(prot_sdb == NULL); | |
1034 | ivecs = blk_rq_count_integrity_sg(rq->q, rq->bio); | |
1035 | ||
1036 | if (scsi_alloc_sgtable(prot_sdb, ivecs, gfp_mask)) { | |
1037 | error = BLKPREP_DEFER; | |
1038 | goto err_exit; | |
1039 | } | |
1040 | ||
1041 | count = blk_rq_map_integrity_sg(rq->q, rq->bio, | |
1042 | prot_sdb->table.sgl); | |
1043 | BUG_ON(unlikely(count > ivecs)); | |
1044 | BUG_ON(unlikely(count > queue_max_integrity_segments(rq->q))); | |
1045 | ||
1046 | cmd->prot_sdb = prot_sdb; | |
1047 | cmd->prot_sdb->table.nents = count; | |
1048 | } | |
1049 | ||
1050 | return BLKPREP_OK ; | |
1051 | ||
1052 | err_exit: | |
1053 | scsi_release_buffers(cmd); | |
1054 | cmd->request->special = NULL; | |
1055 | scsi_put_command(cmd); | |
1056 | return error; | |
1057 | } | |
1058 | EXPORT_SYMBOL(scsi_init_io); | |
1059 | ||
1060 | static struct scsi_cmnd *scsi_get_cmd_from_req(struct scsi_device *sdev, | |
1061 | struct request *req) | |
1062 | { | |
1063 | struct scsi_cmnd *cmd; | |
1064 | ||
1065 | if (!req->special) { | |
1066 | cmd = scsi_get_command(sdev, GFP_ATOMIC); | |
1067 | if (unlikely(!cmd)) | |
1068 | return NULL; | |
1069 | req->special = cmd; | |
1070 | } else { | |
1071 | cmd = req->special; | |
1072 | } | |
1073 | ||
1074 | /* pull a tag out of the request if we have one */ | |
1075 | cmd->tag = req->tag; | |
1076 | cmd->request = req; | |
1077 | ||
1078 | cmd->cmnd = req->cmd; | |
1079 | cmd->prot_op = SCSI_PROT_NORMAL; | |
1080 | ||
1081 | return cmd; | |
1082 | } | |
1083 | ||
1084 | int scsi_setup_blk_pc_cmnd(struct scsi_device *sdev, struct request *req) | |
1085 | { | |
1086 | struct scsi_cmnd *cmd; | |
1087 | int ret = scsi_prep_state_check(sdev, req); | |
1088 | ||
1089 | if (ret != BLKPREP_OK) | |
1090 | return ret; | |
1091 | ||
1092 | cmd = scsi_get_cmd_from_req(sdev, req); | |
1093 | if (unlikely(!cmd)) | |
1094 | return BLKPREP_DEFER; | |
1095 | ||
1096 | /* | |
1097 | * BLOCK_PC requests may transfer data, in which case they must | |
1098 | * a bio attached to them. Or they might contain a SCSI command | |
1099 | * that does not transfer data, in which case they may optionally | |
1100 | * submit a request without an attached bio. | |
1101 | */ | |
1102 | if (req->bio) { | |
1103 | int ret; | |
1104 | ||
1105 | BUG_ON(!req->nr_phys_segments); | |
1106 | ||
1107 | ret = scsi_init_io(cmd, GFP_ATOMIC); | |
1108 | if (unlikely(ret)) | |
1109 | return ret; | |
1110 | } else { | |
1111 | BUG_ON(blk_rq_bytes(req)); | |
1112 | ||
1113 | memset(&cmd->sdb, 0, sizeof(cmd->sdb)); | |
1114 | req->buffer = NULL; | |
1115 | } | |
1116 | ||
1117 | cmd->cmd_len = req->cmd_len; | |
1118 | if (!blk_rq_bytes(req)) | |
1119 | cmd->sc_data_direction = DMA_NONE; | |
1120 | else if (rq_data_dir(req) == WRITE) | |
1121 | cmd->sc_data_direction = DMA_TO_DEVICE; | |
1122 | else | |
1123 | cmd->sc_data_direction = DMA_FROM_DEVICE; | |
1124 | ||
1125 | cmd->transfersize = blk_rq_bytes(req); | |
1126 | cmd->allowed = req->retries; | |
1127 | return BLKPREP_OK; | |
1128 | } | |
1129 | EXPORT_SYMBOL(scsi_setup_blk_pc_cmnd); | |
1130 | ||
1131 | /* | |
1132 | * Setup a REQ_TYPE_FS command. These are simple read/write request | |
1133 | * from filesystems that still need to be translated to SCSI CDBs from | |
1134 | * the ULD. | |
1135 | */ | |
1136 | int scsi_setup_fs_cmnd(struct scsi_device *sdev, struct request *req) | |
1137 | { | |
1138 | struct scsi_cmnd *cmd; | |
1139 | int ret = scsi_prep_state_check(sdev, req); | |
1140 | ||
1141 | if (ret != BLKPREP_OK) | |
1142 | return ret; | |
1143 | ||
1144 | if (unlikely(sdev->scsi_dh_data && sdev->scsi_dh_data->scsi_dh | |
1145 | && sdev->scsi_dh_data->scsi_dh->prep_fn)) { | |
1146 | ret = sdev->scsi_dh_data->scsi_dh->prep_fn(sdev, req); | |
1147 | if (ret != BLKPREP_OK) | |
1148 | return ret; | |
1149 | } | |
1150 | ||
1151 | /* | |
1152 | * Filesystem requests must transfer data. | |
1153 | */ | |
1154 | BUG_ON(!req->nr_phys_segments); | |
1155 | ||
1156 | cmd = scsi_get_cmd_from_req(sdev, req); | |
1157 | if (unlikely(!cmd)) | |
1158 | return BLKPREP_DEFER; | |
1159 | ||
1160 | memset(cmd->cmnd, 0, BLK_MAX_CDB); | |
1161 | return scsi_init_io(cmd, GFP_ATOMIC); | |
1162 | } | |
1163 | EXPORT_SYMBOL(scsi_setup_fs_cmnd); | |
1164 | ||
1165 | int scsi_prep_state_check(struct scsi_device *sdev, struct request *req) | |
1166 | { | |
1167 | int ret = BLKPREP_OK; | |
1168 | ||
1169 | /* | |
1170 | * If the device is not in running state we will reject some | |
1171 | * or all commands. | |
1172 | */ | |
1173 | if (unlikely(sdev->sdev_state != SDEV_RUNNING)) { | |
1174 | switch (sdev->sdev_state) { | |
1175 | case SDEV_OFFLINE: | |
1176 | /* | |
1177 | * If the device is offline we refuse to process any | |
1178 | * commands. The device must be brought online | |
1179 | * before trying any recovery commands. | |
1180 | */ | |
1181 | sdev_printk(KERN_ERR, sdev, | |
1182 | "rejecting I/O to offline device\n"); | |
1183 | ret = BLKPREP_KILL; | |
1184 | break; | |
1185 | case SDEV_DEL: | |
1186 | /* | |
1187 | * If the device is fully deleted, we refuse to | |
1188 | * process any commands as well. | |
1189 | */ | |
1190 | sdev_printk(KERN_ERR, sdev, | |
1191 | "rejecting I/O to dead device\n"); | |
1192 | ret = BLKPREP_KILL; | |
1193 | break; | |
1194 | case SDEV_QUIESCE: | |
1195 | case SDEV_BLOCK: | |
1196 | case SDEV_CREATED_BLOCK: | |
1197 | /* | |
1198 | * If the devices is blocked we defer normal commands. | |
1199 | */ | |
1200 | if (!(req->cmd_flags & REQ_PREEMPT)) | |
1201 | ret = BLKPREP_DEFER; | |
1202 | break; | |
1203 | default: | |
1204 | /* | |
1205 | * For any other not fully online state we only allow | |
1206 | * special commands. In particular any user initiated | |
1207 | * command is not allowed. | |
1208 | */ | |
1209 | if (!(req->cmd_flags & REQ_PREEMPT)) | |
1210 | ret = BLKPREP_KILL; | |
1211 | break; | |
1212 | } | |
1213 | } | |
1214 | return ret; | |
1215 | } | |
1216 | EXPORT_SYMBOL(scsi_prep_state_check); | |
1217 | ||
1218 | int scsi_prep_return(struct request_queue *q, struct request *req, int ret) | |
1219 | { | |
1220 | struct scsi_device *sdev = q->queuedata; | |
1221 | ||
1222 | switch (ret) { | |
1223 | case BLKPREP_KILL: | |
1224 | req->errors = DID_NO_CONNECT << 16; | |
1225 | /* release the command and kill it */ | |
1226 | if (req->special) { | |
1227 | struct scsi_cmnd *cmd = req->special; | |
1228 | scsi_release_buffers(cmd); | |
1229 | scsi_put_command(cmd); | |
1230 | req->special = NULL; | |
1231 | } | |
1232 | break; | |
1233 | case BLKPREP_DEFER: | |
1234 | /* | |
1235 | * If we defer, the blk_peek_request() returns NULL, but the | |
1236 | * queue must be restarted, so we schedule a callback to happen | |
1237 | * shortly. | |
1238 | */ | |
1239 | if (sdev->device_busy == 0) | |
1240 | blk_delay_queue(q, SCSI_QUEUE_DELAY); | |
1241 | break; | |
1242 | default: | |
1243 | req->cmd_flags |= REQ_DONTPREP; | |
1244 | } | |
1245 | ||
1246 | return ret; | |
1247 | } | |
1248 | EXPORT_SYMBOL(scsi_prep_return); | |
1249 | ||
1250 | int scsi_prep_fn(struct request_queue *q, struct request *req) | |
1251 | { | |
1252 | struct scsi_device *sdev = q->queuedata; | |
1253 | int ret = BLKPREP_KILL; | |
1254 | ||
1255 | if (req->cmd_type == REQ_TYPE_BLOCK_PC) | |
1256 | ret = scsi_setup_blk_pc_cmnd(sdev, req); | |
1257 | return scsi_prep_return(q, req, ret); | |
1258 | } | |
1259 | EXPORT_SYMBOL(scsi_prep_fn); | |
1260 | ||
1261 | /* | |
1262 | * scsi_dev_queue_ready: if we can send requests to sdev, return 1 else | |
1263 | * return 0. | |
1264 | * | |
1265 | * Called with the queue_lock held. | |
1266 | */ | |
1267 | static inline int scsi_dev_queue_ready(struct request_queue *q, | |
1268 | struct scsi_device *sdev) | |
1269 | { | |
1270 | if (sdev->device_busy == 0 && sdev->device_blocked) { | |
1271 | /* | |
1272 | * unblock after device_blocked iterates to zero | |
1273 | */ | |
1274 | if (--sdev->device_blocked == 0) { | |
1275 | SCSI_LOG_MLQUEUE(3, | |
1276 | sdev_printk(KERN_INFO, sdev, | |
1277 | "unblocking device at zero depth\n")); | |
1278 | } else { | |
1279 | blk_delay_queue(q, SCSI_QUEUE_DELAY); | |
1280 | return 0; | |
1281 | } | |
1282 | } | |
1283 | if (scsi_device_is_busy(sdev)) | |
1284 | return 0; | |
1285 | ||
1286 | return 1; | |
1287 | } | |
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 | * Called with the host lock held. | |
1295 | */ | |
1296 | static inline int scsi_target_queue_ready(struct Scsi_Host *shost, | |
1297 | struct scsi_device *sdev) | |
1298 | { | |
1299 | struct scsi_target *starget = scsi_target(sdev); | |
1300 | ||
1301 | if (starget->single_lun) { | |
1302 | if (starget->starget_sdev_user && | |
1303 | starget->starget_sdev_user != sdev) | |
1304 | return 0; | |
1305 | starget->starget_sdev_user = sdev; | |
1306 | } | |
1307 | ||
1308 | if (starget->target_busy == 0 && starget->target_blocked) { | |
1309 | /* | |
1310 | * unblock after target_blocked iterates to zero | |
1311 | */ | |
1312 | if (--starget->target_blocked == 0) { | |
1313 | SCSI_LOG_MLQUEUE(3, starget_printk(KERN_INFO, starget, | |
1314 | "unblocking target at zero depth\n")); | |
1315 | } else | |
1316 | return 0; | |
1317 | } | |
1318 | ||
1319 | if (scsi_target_is_busy(starget)) { | |
1320 | list_move_tail(&sdev->starved_entry, &shost->starved_list); | |
1321 | return 0; | |
1322 | } | |
1323 | ||
1324 | return 1; | |
1325 | } | |
1326 | ||
1327 | /* | |
1328 | * scsi_host_queue_ready: if we can send requests to shost, return 1 else | |
1329 | * return 0. We must end up running the queue again whenever 0 is | |
1330 | * returned, else IO can hang. | |
1331 | * | |
1332 | * Called with host_lock held. | |
1333 | */ | |
1334 | static inline int scsi_host_queue_ready(struct request_queue *q, | |
1335 | struct Scsi_Host *shost, | |
1336 | struct scsi_device *sdev) | |
1337 | { | |
1338 | if (scsi_host_in_recovery(shost)) | |
1339 | return 0; | |
1340 | if (shost->host_busy == 0 && shost->host_blocked) { | |
1341 | /* | |
1342 | * unblock after host_blocked iterates to zero | |
1343 | */ | |
1344 | if (--shost->host_blocked == 0) { | |
1345 | SCSI_LOG_MLQUEUE(3, | |
1346 | printk("scsi%d unblocking host at zero depth\n", | |
1347 | shost->host_no)); | |
1348 | } else { | |
1349 | return 0; | |
1350 | } | |
1351 | } | |
1352 | if (scsi_host_is_busy(shost)) { | |
1353 | if (list_empty(&sdev->starved_entry)) | |
1354 | list_add_tail(&sdev->starved_entry, &shost->starved_list); | |
1355 | return 0; | |
1356 | } | |
1357 | ||
1358 | /* We're OK to process the command, so we can't be starved */ | |
1359 | if (!list_empty(&sdev->starved_entry)) | |
1360 | list_del_init(&sdev->starved_entry); | |
1361 | ||
1362 | return 1; | |
1363 | } | |
1364 | ||
1365 | /* | |
1366 | * Busy state exporting function for request stacking drivers. | |
1367 | * | |
1368 | * For efficiency, no lock is taken to check the busy state of | |
1369 | * shost/starget/sdev, since the returned value is not guaranteed and | |
1370 | * may be changed after request stacking drivers call the function, | |
1371 | * regardless of taking lock or not. | |
1372 | * | |
1373 | * When scsi can't dispatch I/Os anymore and needs to kill I/Os | |
1374 | * (e.g. !sdev), scsi needs to return 'not busy'. | |
1375 | * Otherwise, request stacking drivers may hold requests forever. | |
1376 | */ | |
1377 | static int scsi_lld_busy(struct request_queue *q) | |
1378 | { | |
1379 | struct scsi_device *sdev = q->queuedata; | |
1380 | struct Scsi_Host *shost; | |
1381 | ||
1382 | if (!sdev) | |
1383 | return 0; | |
1384 | ||
1385 | shost = sdev->host; | |
1386 | ||
1387 | /* | |
1388 | * Ignore host/starget busy state. | |
1389 | * Since block layer does not have a concept of fairness across | |
1390 | * multiple queues, congestion of host/starget needs to be handled | |
1391 | * in SCSI layer. | |
1392 | */ | |
1393 | if (scsi_host_in_recovery(shost) || scsi_device_is_busy(sdev)) | |
1394 | return 1; | |
1395 | ||
1396 | return 0; | |
1397 | } | |
1398 | ||
1399 | /* | |
1400 | * Kill a request for a dead device | |
1401 | */ | |
1402 | static void scsi_kill_request(struct request *req, struct request_queue *q) | |
1403 | { | |
1404 | struct scsi_cmnd *cmd = req->special; | |
1405 | struct scsi_device *sdev; | |
1406 | struct scsi_target *starget; | |
1407 | struct Scsi_Host *shost; | |
1408 | ||
1409 | blk_start_request(req); | |
1410 | ||
1411 | scmd_printk(KERN_INFO, cmd, "killing request\n"); | |
1412 | ||
1413 | sdev = cmd->device; | |
1414 | starget = scsi_target(sdev); | |
1415 | shost = sdev->host; | |
1416 | scsi_init_cmd_errh(cmd); | |
1417 | cmd->result = DID_NO_CONNECT << 16; | |
1418 | atomic_inc(&cmd->device->iorequest_cnt); | |
1419 | ||
1420 | /* | |
1421 | * SCSI request completion path will do scsi_device_unbusy(), | |
1422 | * bump busy counts. To bump the counters, we need to dance | |
1423 | * with the locks as normal issue path does. | |
1424 | */ | |
1425 | sdev->device_busy++; | |
1426 | spin_unlock(sdev->request_queue->queue_lock); | |
1427 | spin_lock(shost->host_lock); | |
1428 | shost->host_busy++; | |
1429 | starget->target_busy++; | |
1430 | spin_unlock(shost->host_lock); | |
1431 | spin_lock(sdev->request_queue->queue_lock); | |
1432 | ||
1433 | blk_complete_request(req); | |
1434 | } | |
1435 | ||
1436 | static void scsi_softirq_done(struct request *rq) | |
1437 | { | |
1438 | struct scsi_cmnd *cmd = rq->special; | |
1439 | unsigned long wait_for = (cmd->allowed + 1) * rq->timeout; | |
1440 | int disposition; | |
1441 | ||
1442 | INIT_LIST_HEAD(&cmd->eh_entry); | |
1443 | ||
1444 | atomic_inc(&cmd->device->iodone_cnt); | |
1445 | if (cmd->result) | |
1446 | atomic_inc(&cmd->device->ioerr_cnt); | |
1447 | ||
1448 | disposition = scsi_decide_disposition(cmd); | |
1449 | if (disposition != SUCCESS && | |
1450 | time_before(cmd->jiffies_at_alloc + wait_for, jiffies)) { | |
1451 | sdev_printk(KERN_ERR, cmd->device, | |
1452 | "timing out command, waited %lus\n", | |
1453 | wait_for/HZ); | |
1454 | disposition = SUCCESS; | |
1455 | } | |
1456 | ||
1457 | scsi_log_completion(cmd, disposition); | |
1458 | ||
1459 | switch (disposition) { | |
1460 | case SUCCESS: | |
1461 | scsi_finish_command(cmd); | |
1462 | break; | |
1463 | case NEEDS_RETRY: | |
1464 | scsi_queue_insert(cmd, SCSI_MLQUEUE_EH_RETRY); | |
1465 | break; | |
1466 | case ADD_TO_MLQUEUE: | |
1467 | scsi_queue_insert(cmd, SCSI_MLQUEUE_DEVICE_BUSY); | |
1468 | break; | |
1469 | default: | |
1470 | if (!scsi_eh_scmd_add(cmd, 0)) | |
1471 | scsi_finish_command(cmd); | |
1472 | } | |
1473 | } | |
1474 | ||
1475 | /* | |
1476 | * Function: scsi_request_fn() | |
1477 | * | |
1478 | * Purpose: Main strategy routine for SCSI. | |
1479 | * | |
1480 | * Arguments: q - Pointer to actual queue. | |
1481 | * | |
1482 | * Returns: Nothing | |
1483 | * | |
1484 | * Lock status: IO request lock assumed to be held when called. | |
1485 | */ | |
1486 | static void scsi_request_fn(struct request_queue *q) | |
1487 | { | |
1488 | struct scsi_device *sdev = q->queuedata; | |
1489 | struct Scsi_Host *shost; | |
1490 | struct scsi_cmnd *cmd; | |
1491 | struct request *req; | |
1492 | ||
1493 | if (!sdev) { | |
1494 | while ((req = blk_peek_request(q)) != NULL) | |
1495 | scsi_kill_request(req, q); | |
1496 | return; | |
1497 | } | |
1498 | ||
1499 | if(!get_device(&sdev->sdev_gendev)) | |
1500 | /* We must be tearing the block queue down already */ | |
1501 | return; | |
1502 | ||
1503 | /* | |
1504 | * To start with, we keep looping until the queue is empty, or until | |
1505 | * the host is no longer able to accept any more requests. | |
1506 | */ | |
1507 | shost = sdev->host; | |
1508 | for (;;) { | |
1509 | int rtn; | |
1510 | /* | |
1511 | * get next queueable request. We do this early to make sure | |
1512 | * that the request is fully prepared even if we cannot | |
1513 | * accept it. | |
1514 | */ | |
1515 | req = blk_peek_request(q); | |
1516 | if (!req || !scsi_dev_queue_ready(q, sdev)) | |
1517 | break; | |
1518 | ||
1519 | if (unlikely(!scsi_device_online(sdev))) { | |
1520 | sdev_printk(KERN_ERR, sdev, | |
1521 | "rejecting I/O to offline device\n"); | |
1522 | scsi_kill_request(req, q); | |
1523 | continue; | |
1524 | } | |
1525 | ||
1526 | ||
1527 | /* | |
1528 | * Remove the request from the request list. | |
1529 | */ | |
1530 | if (!(blk_queue_tagged(q) && !blk_queue_start_tag(q, req))) | |
1531 | blk_start_request(req); | |
1532 | sdev->device_busy++; | |
1533 | ||
1534 | spin_unlock(q->queue_lock); | |
1535 | cmd = req->special; | |
1536 | if (unlikely(cmd == NULL)) { | |
1537 | printk(KERN_CRIT "impossible request in %s.\n" | |
1538 | "please mail a stack trace to " | |
1539 | "linux-scsi@vger.kernel.org\n", | |
1540 | __func__); | |
1541 | blk_dump_rq_flags(req, "foo"); | |
1542 | BUG(); | |
1543 | } | |
1544 | spin_lock(shost->host_lock); | |
1545 | ||
1546 | /* | |
1547 | * We hit this when the driver is using a host wide | |
1548 | * tag map. For device level tag maps the queue_depth check | |
1549 | * in the device ready fn would prevent us from trying | |
1550 | * to allocate a tag. Since the map is a shared host resource | |
1551 | * we add the dev to the starved list so it eventually gets | |
1552 | * a run when a tag is freed. | |
1553 | */ | |
1554 | if (blk_queue_tagged(q) && !blk_rq_tagged(req)) { | |
1555 | if (list_empty(&sdev->starved_entry)) | |
1556 | list_add_tail(&sdev->starved_entry, | |
1557 | &shost->starved_list); | |
1558 | goto not_ready; | |
1559 | } | |
1560 | ||
1561 | if (!scsi_target_queue_ready(shost, sdev)) | |
1562 | goto not_ready; | |
1563 | ||
1564 | if (!scsi_host_queue_ready(q, shost, sdev)) | |
1565 | goto not_ready; | |
1566 | ||
1567 | scsi_target(sdev)->target_busy++; | |
1568 | shost->host_busy++; | |
1569 | ||
1570 | /* | |
1571 | * XXX(hch): This is rather suboptimal, scsi_dispatch_cmd will | |
1572 | * take the lock again. | |
1573 | */ | |
1574 | spin_unlock_irq(shost->host_lock); | |
1575 | ||
1576 | /* | |
1577 | * Finally, initialize any error handling parameters, and set up | |
1578 | * the timers for timeouts. | |
1579 | */ | |
1580 | scsi_init_cmd_errh(cmd); | |
1581 | ||
1582 | /* | |
1583 | * Dispatch the command to the low-level driver. | |
1584 | */ | |
1585 | rtn = scsi_dispatch_cmd(cmd); | |
1586 | spin_lock_irq(q->queue_lock); | |
1587 | if (rtn) | |
1588 | goto out_delay; | |
1589 | } | |
1590 | ||
1591 | goto out; | |
1592 | ||
1593 | not_ready: | |
1594 | spin_unlock_irq(shost->host_lock); | |
1595 | ||
1596 | /* | |
1597 | * lock q, handle tag, requeue req, and decrement device_busy. We | |
1598 | * must return with queue_lock held. | |
1599 | * | |
1600 | * Decrementing device_busy without checking it is OK, as all such | |
1601 | * cases (host limits or settings) should run the queue at some | |
1602 | * later time. | |
1603 | */ | |
1604 | spin_lock_irq(q->queue_lock); | |
1605 | blk_requeue_request(q, req); | |
1606 | sdev->device_busy--; | |
1607 | out_delay: | |
1608 | if (sdev->device_busy == 0) | |
1609 | blk_delay_queue(q, SCSI_QUEUE_DELAY); | |
1610 | out: | |
1611 | /* must be careful here...if we trigger the ->remove() function | |
1612 | * we cannot be holding the q lock */ | |
1613 | spin_unlock_irq(q->queue_lock); | |
1614 | put_device(&sdev->sdev_gendev); | |
1615 | spin_lock_irq(q->queue_lock); | |
1616 | } | |
1617 | ||
1618 | u64 scsi_calculate_bounce_limit(struct Scsi_Host *shost) | |
1619 | { | |
1620 | struct device *host_dev; | |
1621 | u64 bounce_limit = 0xffffffff; | |
1622 | ||
1623 | if (shost->unchecked_isa_dma) | |
1624 | return BLK_BOUNCE_ISA; | |
1625 | /* | |
1626 | * Platforms with virtual-DMA translation | |
1627 | * hardware have no practical limit. | |
1628 | */ | |
1629 | if (!PCI_DMA_BUS_IS_PHYS) | |
1630 | return BLK_BOUNCE_ANY; | |
1631 | ||
1632 | host_dev = scsi_get_device(shost); | |
1633 | if (host_dev && host_dev->dma_mask) | |
1634 | bounce_limit = *host_dev->dma_mask; | |
1635 | ||
1636 | return bounce_limit; | |
1637 | } | |
1638 | EXPORT_SYMBOL(scsi_calculate_bounce_limit); | |
1639 | ||
1640 | struct request_queue *__scsi_alloc_queue(struct Scsi_Host *shost, | |
1641 | request_fn_proc *request_fn) | |
1642 | { | |
1643 | struct request_queue *q; | |
1644 | struct device *dev = shost->dma_dev; | |
1645 | ||
1646 | q = blk_init_queue(request_fn, NULL); | |
1647 | if (!q) | |
1648 | return NULL; | |
1649 | ||
1650 | /* | |
1651 | * this limit is imposed by hardware restrictions | |
1652 | */ | |
1653 | blk_queue_max_segments(q, min_t(unsigned short, shost->sg_tablesize, | |
1654 | SCSI_MAX_SG_CHAIN_SEGMENTS)); | |
1655 | ||
1656 | if (scsi_host_prot_dma(shost)) { | |
1657 | shost->sg_prot_tablesize = | |
1658 | min_not_zero(shost->sg_prot_tablesize, | |
1659 | (unsigned short)SCSI_MAX_PROT_SG_SEGMENTS); | |
1660 | BUG_ON(shost->sg_prot_tablesize < shost->sg_tablesize); | |
1661 | blk_queue_max_integrity_segments(q, shost->sg_prot_tablesize); | |
1662 | } | |
1663 | ||
1664 | blk_queue_max_hw_sectors(q, shost->max_sectors); | |
1665 | blk_queue_bounce_limit(q, scsi_calculate_bounce_limit(shost)); | |
1666 | blk_queue_segment_boundary(q, shost->dma_boundary); | |
1667 | dma_set_seg_boundary(dev, shost->dma_boundary); | |
1668 | ||
1669 | blk_queue_max_segment_size(q, dma_get_max_seg_size(dev)); | |
1670 | ||
1671 | if (!shost->use_clustering) | |
1672 | q->limits.cluster = 0; | |
1673 | ||
1674 | /* | |
1675 | * set a reasonable default alignment on word boundaries: the | |
1676 | * host and device may alter it using | |
1677 | * blk_queue_update_dma_alignment() later. | |
1678 | */ | |
1679 | blk_queue_dma_alignment(q, 0x03); | |
1680 | ||
1681 | return q; | |
1682 | } | |
1683 | EXPORT_SYMBOL(__scsi_alloc_queue); | |
1684 | ||
1685 | struct request_queue *scsi_alloc_queue(struct scsi_device *sdev) | |
1686 | { | |
1687 | struct request_queue *q; | |
1688 | ||
1689 | q = __scsi_alloc_queue(sdev->host, scsi_request_fn); | |
1690 | if (!q) | |
1691 | return NULL; | |
1692 | ||
1693 | blk_queue_prep_rq(q, scsi_prep_fn); | |
1694 | blk_queue_softirq_done(q, scsi_softirq_done); | |
1695 | blk_queue_rq_timed_out(q, scsi_times_out); | |
1696 | blk_queue_lld_busy(q, scsi_lld_busy); | |
1697 | return q; | |
1698 | } | |
1699 | ||
1700 | void scsi_free_queue(struct request_queue *q) | |
1701 | { | |
1702 | unsigned long flags; | |
1703 | ||
1704 | WARN_ON(q->queuedata); | |
1705 | ||
1706 | /* cause scsi_request_fn() to kill all non-finished requests */ | |
1707 | spin_lock_irqsave(q->queue_lock, flags); | |
1708 | q->request_fn(q); | |
1709 | spin_unlock_irqrestore(q->queue_lock, flags); | |
1710 | ||
1711 | blk_cleanup_queue(q); | |
1712 | } | |
1713 | ||
1714 | /* | |
1715 | * Function: scsi_block_requests() | |
1716 | * | |
1717 | * Purpose: Utility function used by low-level drivers to prevent further | |
1718 | * commands from being queued to the device. | |
1719 | * | |
1720 | * Arguments: shost - Host in question | |
1721 | * | |
1722 | * Returns: Nothing | |
1723 | * | |
1724 | * Lock status: No locks are assumed held. | |
1725 | * | |
1726 | * Notes: There is no timer nor any other means by which the requests | |
1727 | * get unblocked other than the low-level driver calling | |
1728 | * scsi_unblock_requests(). | |
1729 | */ | |
1730 | void scsi_block_requests(struct Scsi_Host *shost) | |
1731 | { | |
1732 | shost->host_self_blocked = 1; | |
1733 | } | |
1734 | EXPORT_SYMBOL(scsi_block_requests); | |
1735 | ||
1736 | /* | |
1737 | * Function: scsi_unblock_requests() | |
1738 | * | |
1739 | * Purpose: Utility function used by low-level drivers to allow further | |
1740 | * commands from being queued to the device. | |
1741 | * | |
1742 | * Arguments: shost - Host in question | |
1743 | * | |
1744 | * Returns: Nothing | |
1745 | * | |
1746 | * Lock status: No locks are assumed held. | |
1747 | * | |
1748 | * Notes: There is no timer nor any other means by which the requests | |
1749 | * get unblocked other than the low-level driver calling | |
1750 | * scsi_unblock_requests(). | |
1751 | * | |
1752 | * This is done as an API function so that changes to the | |
1753 | * internals of the scsi mid-layer won't require wholesale | |
1754 | * changes to drivers that use this feature. | |
1755 | */ | |
1756 | void scsi_unblock_requests(struct Scsi_Host *shost) | |
1757 | { | |
1758 | shost->host_self_blocked = 0; | |
1759 | scsi_run_host_queues(shost); | |
1760 | } | |
1761 | EXPORT_SYMBOL(scsi_unblock_requests); | |
1762 | ||
1763 | int __init scsi_init_queue(void) | |
1764 | { | |
1765 | int i; | |
1766 | ||
1767 | scsi_sdb_cache = kmem_cache_create("scsi_data_buffer", | |
1768 | sizeof(struct scsi_data_buffer), | |
1769 | 0, 0, NULL); | |
1770 | if (!scsi_sdb_cache) { | |
1771 | printk(KERN_ERR "SCSI: can't init scsi sdb cache\n"); | |
1772 | return -ENOMEM; | |
1773 | } | |
1774 | ||
1775 | for (i = 0; i < SG_MEMPOOL_NR; i++) { | |
1776 | struct scsi_host_sg_pool *sgp = scsi_sg_pools + i; | |
1777 | int size = sgp->size * sizeof(struct scatterlist); | |
1778 | ||
1779 | sgp->slab = kmem_cache_create(sgp->name, size, 0, | |
1780 | SLAB_HWCACHE_ALIGN, NULL); | |
1781 | if (!sgp->slab) { | |
1782 | printk(KERN_ERR "SCSI: can't init sg slab %s\n", | |
1783 | sgp->name); | |
1784 | goto cleanup_sdb; | |
1785 | } | |
1786 | ||
1787 | sgp->pool = mempool_create_slab_pool(SG_MEMPOOL_SIZE, | |
1788 | sgp->slab); | |
1789 | if (!sgp->pool) { | |
1790 | printk(KERN_ERR "SCSI: can't init sg mempool %s\n", | |
1791 | sgp->name); | |
1792 | goto cleanup_sdb; | |
1793 | } | |
1794 | } | |
1795 | ||
1796 | return 0; | |
1797 | ||
1798 | cleanup_sdb: | |
1799 | for (i = 0; i < SG_MEMPOOL_NR; i++) { | |
1800 | struct scsi_host_sg_pool *sgp = scsi_sg_pools + i; | |
1801 | if (sgp->pool) | |
1802 | mempool_destroy(sgp->pool); | |
1803 | if (sgp->slab) | |
1804 | kmem_cache_destroy(sgp->slab); | |
1805 | } | |
1806 | kmem_cache_destroy(scsi_sdb_cache); | |
1807 | ||
1808 | return -ENOMEM; | |
1809 | } | |
1810 | ||
1811 | void scsi_exit_queue(void) | |
1812 | { | |
1813 | int i; | |
1814 | ||
1815 | kmem_cache_destroy(scsi_sdb_cache); | |
1816 | ||
1817 | for (i = 0; i < SG_MEMPOOL_NR; i++) { | |
1818 | struct scsi_host_sg_pool *sgp = scsi_sg_pools + i; | |
1819 | mempool_destroy(sgp->pool); | |
1820 | kmem_cache_destroy(sgp->slab); | |
1821 | } | |
1822 | } | |
1823 | ||
1824 | /** | |
1825 | * scsi_mode_select - issue a mode select | |
1826 | * @sdev: SCSI device to be queried | |
1827 | * @pf: Page format bit (1 == standard, 0 == vendor specific) | |
1828 | * @sp: Save page bit (0 == don't save, 1 == save) | |
1829 | * @modepage: mode page being requested | |
1830 | * @buffer: request buffer (may not be smaller than eight bytes) | |
1831 | * @len: length of request buffer. | |
1832 | * @timeout: command timeout | |
1833 | * @retries: number of retries before failing | |
1834 | * @data: returns a structure abstracting the mode header data | |
1835 | * @sshdr: place to put sense data (or NULL if no sense to be collected). | |
1836 | * must be SCSI_SENSE_BUFFERSIZE big. | |
1837 | * | |
1838 | * Returns zero if successful; negative error number or scsi | |
1839 | * status on error | |
1840 | * | |
1841 | */ | |
1842 | int | |
1843 | scsi_mode_select(struct scsi_device *sdev, int pf, int sp, int modepage, | |
1844 | unsigned char *buffer, int len, int timeout, int retries, | |
1845 | struct scsi_mode_data *data, struct scsi_sense_hdr *sshdr) | |
1846 | { | |
1847 | unsigned char cmd[10]; | |
1848 | unsigned char *real_buffer; | |
1849 | int ret; | |
1850 | ||
1851 | memset(cmd, 0, sizeof(cmd)); | |
1852 | cmd[1] = (pf ? 0x10 : 0) | (sp ? 0x01 : 0); | |
1853 | ||
1854 | if (sdev->use_10_for_ms) { | |
1855 | if (len > 65535) | |
1856 | return -EINVAL; | |
1857 | real_buffer = kmalloc(8 + len, GFP_KERNEL); | |
1858 | if (!real_buffer) | |
1859 | return -ENOMEM; | |
1860 | memcpy(real_buffer + 8, buffer, len); | |
1861 | len += 8; | |
1862 | real_buffer[0] = 0; | |
1863 | real_buffer[1] = 0; | |
1864 | real_buffer[2] = data->medium_type; | |
1865 | real_buffer[3] = data->device_specific; | |
1866 | real_buffer[4] = data->longlba ? 0x01 : 0; | |
1867 | real_buffer[5] = 0; | |
1868 | real_buffer[6] = data->block_descriptor_length >> 8; | |
1869 | real_buffer[7] = data->block_descriptor_length; | |
1870 | ||
1871 | cmd[0] = MODE_SELECT_10; | |
1872 | cmd[7] = len >> 8; | |
1873 | cmd[8] = len; | |
1874 | } else { | |
1875 | if (len > 255 || data->block_descriptor_length > 255 || | |
1876 | data->longlba) | |
1877 | return -EINVAL; | |
1878 | ||
1879 | real_buffer = kmalloc(4 + len, GFP_KERNEL); | |
1880 | if (!real_buffer) | |
1881 | return -ENOMEM; | |
1882 | memcpy(real_buffer + 4, buffer, len); | |
1883 | len += 4; | |
1884 | real_buffer[0] = 0; | |
1885 | real_buffer[1] = data->medium_type; | |
1886 | real_buffer[2] = data->device_specific; | |
1887 | real_buffer[3] = data->block_descriptor_length; | |
1888 | ||
1889 | ||
1890 | cmd[0] = MODE_SELECT; | |
1891 | cmd[4] = len; | |
1892 | } | |
1893 | ||
1894 | ret = scsi_execute_req(sdev, cmd, DMA_TO_DEVICE, real_buffer, len, | |
1895 | sshdr, timeout, retries, NULL); | |
1896 | kfree(real_buffer); | |
1897 | return ret; | |
1898 | } | |
1899 | EXPORT_SYMBOL_GPL(scsi_mode_select); | |
1900 | ||
1901 | /** | |
1902 | * scsi_mode_sense - issue a mode sense, falling back from 10 to six bytes if necessary. | |
1903 | * @sdev: SCSI device to be queried | |
1904 | * @dbd: set if mode sense will allow block descriptors to be returned | |
1905 | * @modepage: mode page being requested | |
1906 | * @buffer: request buffer (may not be smaller than eight bytes) | |
1907 | * @len: length of request buffer. | |
1908 | * @timeout: command timeout | |
1909 | * @retries: number of retries before failing | |
1910 | * @data: returns a structure abstracting the mode header data | |
1911 | * @sshdr: place to put sense data (or NULL if no sense to be collected). | |
1912 | * must be SCSI_SENSE_BUFFERSIZE big. | |
1913 | * | |
1914 | * Returns zero if unsuccessful, or the header offset (either 4 | |
1915 | * or 8 depending on whether a six or ten byte command was | |
1916 | * issued) if successful. | |
1917 | */ | |
1918 | int | |
1919 | scsi_mode_sense(struct scsi_device *sdev, int dbd, int modepage, | |
1920 | unsigned char *buffer, int len, int timeout, int retries, | |
1921 | struct scsi_mode_data *data, struct scsi_sense_hdr *sshdr) | |
1922 | { | |
1923 | unsigned char cmd[12]; | |
1924 | int use_10_for_ms; | |
1925 | int header_length; | |
1926 | int result; | |
1927 | struct scsi_sense_hdr my_sshdr; | |
1928 | ||
1929 | memset(data, 0, sizeof(*data)); | |
1930 | memset(&cmd[0], 0, 12); | |
1931 | cmd[1] = dbd & 0x18; /* allows DBD and LLBA bits */ | |
1932 | cmd[2] = modepage; | |
1933 | ||
1934 | /* caller might not be interested in sense, but we need it */ | |
1935 | if (!sshdr) | |
1936 | sshdr = &my_sshdr; | |
1937 | ||
1938 | retry: | |
1939 | use_10_for_ms = sdev->use_10_for_ms; | |
1940 | ||
1941 | if (use_10_for_ms) { | |
1942 | if (len < 8) | |
1943 | len = 8; | |
1944 | ||
1945 | cmd[0] = MODE_SENSE_10; | |
1946 | cmd[8] = len; | |
1947 | header_length = 8; | |
1948 | } else { | |
1949 | if (len < 4) | |
1950 | len = 4; | |
1951 | ||
1952 | cmd[0] = MODE_SENSE; | |
1953 | cmd[4] = len; | |
1954 | header_length = 4; | |
1955 | } | |
1956 | ||
1957 | memset(buffer, 0, len); | |
1958 | ||
1959 | result = scsi_execute_req(sdev, cmd, DMA_FROM_DEVICE, buffer, len, | |
1960 | sshdr, timeout, retries, NULL); | |
1961 | ||
1962 | /* This code looks awful: what it's doing is making sure an | |
1963 | * ILLEGAL REQUEST sense return identifies the actual command | |
1964 | * byte as the problem. MODE_SENSE commands can return | |
1965 | * ILLEGAL REQUEST if the code page isn't supported */ | |
1966 | ||
1967 | if (use_10_for_ms && !scsi_status_is_good(result) && | |
1968 | (driver_byte(result) & DRIVER_SENSE)) { | |
1969 | if (scsi_sense_valid(sshdr)) { | |
1970 | if ((sshdr->sense_key == ILLEGAL_REQUEST) && | |
1971 | (sshdr->asc == 0x20) && (sshdr->ascq == 0)) { | |
1972 | /* | |
1973 | * Invalid command operation code | |
1974 | */ | |
1975 | sdev->use_10_for_ms = 0; | |
1976 | goto retry; | |
1977 | } | |
1978 | } | |
1979 | } | |
1980 | ||
1981 | if(scsi_status_is_good(result)) { | |
1982 | if (unlikely(buffer[0] == 0x86 && buffer[1] == 0x0b && | |
1983 | (modepage == 6 || modepage == 8))) { | |
1984 | /* Initio breakage? */ | |
1985 | header_length = 0; | |
1986 | data->length = 13; | |
1987 | data->medium_type = 0; | |
1988 | data->device_specific = 0; | |
1989 | data->longlba = 0; | |
1990 | data->block_descriptor_length = 0; | |
1991 | } else if(use_10_for_ms) { | |
1992 | data->length = buffer[0]*256 + buffer[1] + 2; | |
1993 | data->medium_type = buffer[2]; | |
1994 | data->device_specific = buffer[3]; | |
1995 | data->longlba = buffer[4] & 0x01; | |
1996 | data->block_descriptor_length = buffer[6]*256 | |
1997 | + buffer[7]; | |
1998 | } else { | |
1999 | data->length = buffer[0] + 1; | |
2000 | data->medium_type = buffer[1]; | |
2001 | data->device_specific = buffer[2]; | |
2002 | data->block_descriptor_length = buffer[3]; | |
2003 | } | |
2004 | data->header_length = header_length; | |
2005 | } | |
2006 | ||
2007 | return result; | |
2008 | } | |
2009 | EXPORT_SYMBOL(scsi_mode_sense); | |
2010 | ||
2011 | /** | |
2012 | * scsi_test_unit_ready - test if unit is ready | |
2013 | * @sdev: scsi device to change the state of. | |
2014 | * @timeout: command timeout | |
2015 | * @retries: number of retries before failing | |
2016 | * @sshdr_external: Optional pointer to struct scsi_sense_hdr for | |
2017 | * returning sense. Make sure that this is cleared before passing | |
2018 | * in. | |
2019 | * | |
2020 | * Returns zero if unsuccessful or an error if TUR failed. For | |
2021 | * removable media, UNIT_ATTENTION sets ->changed flag. | |
2022 | **/ | |
2023 | int | |
2024 | scsi_test_unit_ready(struct scsi_device *sdev, int timeout, int retries, | |
2025 | struct scsi_sense_hdr *sshdr_external) | |
2026 | { | |
2027 | char cmd[] = { | |
2028 | TEST_UNIT_READY, 0, 0, 0, 0, 0, | |
2029 | }; | |
2030 | struct scsi_sense_hdr *sshdr; | |
2031 | int result; | |
2032 | ||
2033 | if (!sshdr_external) | |
2034 | sshdr = kzalloc(sizeof(*sshdr), GFP_KERNEL); | |
2035 | else | |
2036 | sshdr = sshdr_external; | |
2037 | ||
2038 | /* try to eat the UNIT_ATTENTION if there are enough retries */ | |
2039 | do { | |
2040 | result = scsi_execute_req(sdev, cmd, DMA_NONE, NULL, 0, sshdr, | |
2041 | timeout, retries, NULL); | |
2042 | if (sdev->removable && scsi_sense_valid(sshdr) && | |
2043 | sshdr->sense_key == UNIT_ATTENTION) | |
2044 | sdev->changed = 1; | |
2045 | } while (scsi_sense_valid(sshdr) && | |
2046 | sshdr->sense_key == UNIT_ATTENTION && --retries); | |
2047 | ||
2048 | if (!sshdr_external) | |
2049 | kfree(sshdr); | |
2050 | return result; | |
2051 | } | |
2052 | EXPORT_SYMBOL(scsi_test_unit_ready); | |
2053 | ||
2054 | /** | |
2055 | * scsi_device_set_state - Take the given device through the device state model. | |
2056 | * @sdev: scsi device to change the state of. | |
2057 | * @state: state to change to. | |
2058 | * | |
2059 | * Returns zero if unsuccessful or an error if the requested | |
2060 | * transition is illegal. | |
2061 | */ | |
2062 | int | |
2063 | scsi_device_set_state(struct scsi_device *sdev, enum scsi_device_state state) | |
2064 | { | |
2065 | enum scsi_device_state oldstate = sdev->sdev_state; | |
2066 | ||
2067 | if (state == oldstate) | |
2068 | return 0; | |
2069 | ||
2070 | switch (state) { | |
2071 | case SDEV_CREATED: | |
2072 | switch (oldstate) { | |
2073 | case SDEV_CREATED_BLOCK: | |
2074 | break; | |
2075 | default: | |
2076 | goto illegal; | |
2077 | } | |
2078 | break; | |
2079 | ||
2080 | case SDEV_RUNNING: | |
2081 | switch (oldstate) { | |
2082 | case SDEV_CREATED: | |
2083 | case SDEV_OFFLINE: | |
2084 | case SDEV_QUIESCE: | |
2085 | case SDEV_BLOCK: | |
2086 | break; | |
2087 | default: | |
2088 | goto illegal; | |
2089 | } | |
2090 | break; | |
2091 | ||
2092 | case SDEV_QUIESCE: | |
2093 | switch (oldstate) { | |
2094 | case SDEV_RUNNING: | |
2095 | case SDEV_OFFLINE: | |
2096 | break; | |
2097 | default: | |
2098 | goto illegal; | |
2099 | } | |
2100 | break; | |
2101 | ||
2102 | case SDEV_OFFLINE: | |
2103 | switch (oldstate) { | |
2104 | case SDEV_CREATED: | |
2105 | case SDEV_RUNNING: | |
2106 | case SDEV_QUIESCE: | |
2107 | case SDEV_BLOCK: | |
2108 | break; | |
2109 | default: | |
2110 | goto illegal; | |
2111 | } | |
2112 | break; | |
2113 | ||
2114 | case SDEV_BLOCK: | |
2115 | switch (oldstate) { | |
2116 | case SDEV_RUNNING: | |
2117 | case SDEV_CREATED_BLOCK: | |
2118 | break; | |
2119 | default: | |
2120 | goto illegal; | |
2121 | } | |
2122 | break; | |
2123 | ||
2124 | case SDEV_CREATED_BLOCK: | |
2125 | switch (oldstate) { | |
2126 | case SDEV_CREATED: | |
2127 | break; | |
2128 | default: | |
2129 | goto illegal; | |
2130 | } | |
2131 | break; | |
2132 | ||
2133 | case SDEV_CANCEL: | |
2134 | switch (oldstate) { | |
2135 | case SDEV_CREATED: | |
2136 | case SDEV_RUNNING: | |
2137 | case SDEV_QUIESCE: | |
2138 | case SDEV_OFFLINE: | |
2139 | case SDEV_BLOCK: | |
2140 | break; | |
2141 | default: | |
2142 | goto illegal; | |
2143 | } | |
2144 | break; | |
2145 | ||
2146 | case SDEV_DEL: | |
2147 | switch (oldstate) { | |
2148 | case SDEV_CREATED: | |
2149 | case SDEV_RUNNING: | |
2150 | case SDEV_OFFLINE: | |
2151 | case SDEV_CANCEL: | |
2152 | break; | |
2153 | default: | |
2154 | goto illegal; | |
2155 | } | |
2156 | break; | |
2157 | ||
2158 | } | |
2159 | sdev->sdev_state = state; | |
2160 | return 0; | |
2161 | ||
2162 | illegal: | |
2163 | SCSI_LOG_ERROR_RECOVERY(1, | |
2164 | sdev_printk(KERN_ERR, sdev, | |
2165 | "Illegal state transition %s->%s\n", | |
2166 | scsi_device_state_name(oldstate), | |
2167 | scsi_device_state_name(state)) | |
2168 | ); | |
2169 | return -EINVAL; | |
2170 | } | |
2171 | EXPORT_SYMBOL(scsi_device_set_state); | |
2172 | ||
2173 | /** | |
2174 | * sdev_evt_emit - emit a single SCSI device uevent | |
2175 | * @sdev: associated SCSI device | |
2176 | * @evt: event to emit | |
2177 | * | |
2178 | * Send a single uevent (scsi_event) to the associated scsi_device. | |
2179 | */ | |
2180 | static void scsi_evt_emit(struct scsi_device *sdev, struct scsi_event *evt) | |
2181 | { | |
2182 | int idx = 0; | |
2183 | char *envp[3]; | |
2184 | ||
2185 | switch (evt->evt_type) { | |
2186 | case SDEV_EVT_MEDIA_CHANGE: | |
2187 | envp[idx++] = "SDEV_MEDIA_CHANGE=1"; | |
2188 | break; | |
2189 | ||
2190 | default: | |
2191 | /* do nothing */ | |
2192 | break; | |
2193 | } | |
2194 | ||
2195 | envp[idx++] = NULL; | |
2196 | ||
2197 | kobject_uevent_env(&sdev->sdev_gendev.kobj, KOBJ_CHANGE, envp); | |
2198 | } | |
2199 | ||
2200 | /** | |
2201 | * sdev_evt_thread - send a uevent for each scsi event | |
2202 | * @work: work struct for scsi_device | |
2203 | * | |
2204 | * Dispatch queued events to their associated scsi_device kobjects | |
2205 | * as uevents. | |
2206 | */ | |
2207 | void scsi_evt_thread(struct work_struct *work) | |
2208 | { | |
2209 | struct scsi_device *sdev; | |
2210 | LIST_HEAD(event_list); | |
2211 | ||
2212 | sdev = container_of(work, struct scsi_device, event_work); | |
2213 | ||
2214 | while (1) { | |
2215 | struct scsi_event *evt; | |
2216 | struct list_head *this, *tmp; | |
2217 | unsigned long flags; | |
2218 | ||
2219 | spin_lock_irqsave(&sdev->list_lock, flags); | |
2220 | list_splice_init(&sdev->event_list, &event_list); | |
2221 | spin_unlock_irqrestore(&sdev->list_lock, flags); | |
2222 | ||
2223 | if (list_empty(&event_list)) | |
2224 | break; | |
2225 | ||
2226 | list_for_each_safe(this, tmp, &event_list) { | |
2227 | evt = list_entry(this, struct scsi_event, node); | |
2228 | list_del(&evt->node); | |
2229 | scsi_evt_emit(sdev, evt); | |
2230 | kfree(evt); | |
2231 | } | |
2232 | } | |
2233 | } | |
2234 | ||
2235 | /** | |
2236 | * sdev_evt_send - send asserted event to uevent thread | |
2237 | * @sdev: scsi_device event occurred on | |
2238 | * @evt: event to send | |
2239 | * | |
2240 | * Assert scsi device event asynchronously. | |
2241 | */ | |
2242 | void sdev_evt_send(struct scsi_device *sdev, struct scsi_event *evt) | |
2243 | { | |
2244 | unsigned long flags; | |
2245 | ||
2246 | #if 0 | |
2247 | /* FIXME: currently this check eliminates all media change events | |
2248 | * for polled devices. Need to update to discriminate between AN | |
2249 | * and polled events */ | |
2250 | if (!test_bit(evt->evt_type, sdev->supported_events)) { | |
2251 | kfree(evt); | |
2252 | return; | |
2253 | } | |
2254 | #endif | |
2255 | ||
2256 | spin_lock_irqsave(&sdev->list_lock, flags); | |
2257 | list_add_tail(&evt->node, &sdev->event_list); | |
2258 | schedule_work(&sdev->event_work); | |
2259 | spin_unlock_irqrestore(&sdev->list_lock, flags); | |
2260 | } | |
2261 | EXPORT_SYMBOL_GPL(sdev_evt_send); | |
2262 | ||
2263 | /** | |
2264 | * sdev_evt_alloc - allocate a new scsi event | |
2265 | * @evt_type: type of event to allocate | |
2266 | * @gfpflags: GFP flags for allocation | |
2267 | * | |
2268 | * Allocates and returns a new scsi_event. | |
2269 | */ | |
2270 | struct scsi_event *sdev_evt_alloc(enum scsi_device_event evt_type, | |
2271 | gfp_t gfpflags) | |
2272 | { | |
2273 | struct scsi_event *evt = kzalloc(sizeof(struct scsi_event), gfpflags); | |
2274 | if (!evt) | |
2275 | return NULL; | |
2276 | ||
2277 | evt->evt_type = evt_type; | |
2278 | INIT_LIST_HEAD(&evt->node); | |
2279 | ||
2280 | /* evt_type-specific initialization, if any */ | |
2281 | switch (evt_type) { | |
2282 | case SDEV_EVT_MEDIA_CHANGE: | |
2283 | default: | |
2284 | /* do nothing */ | |
2285 | break; | |
2286 | } | |
2287 | ||
2288 | return evt; | |
2289 | } | |
2290 | EXPORT_SYMBOL_GPL(sdev_evt_alloc); | |
2291 | ||
2292 | /** | |
2293 | * sdev_evt_send_simple - send asserted event to uevent thread | |
2294 | * @sdev: scsi_device event occurred on | |
2295 | * @evt_type: type of event to send | |
2296 | * @gfpflags: GFP flags for allocation | |
2297 | * | |
2298 | * Assert scsi device event asynchronously, given an event type. | |
2299 | */ | |
2300 | void sdev_evt_send_simple(struct scsi_device *sdev, | |
2301 | enum scsi_device_event evt_type, gfp_t gfpflags) | |
2302 | { | |
2303 | struct scsi_event *evt = sdev_evt_alloc(evt_type, gfpflags); | |
2304 | if (!evt) { | |
2305 | sdev_printk(KERN_ERR, sdev, "event %d eaten due to OOM\n", | |
2306 | evt_type); | |
2307 | return; | |
2308 | } | |
2309 | ||
2310 | sdev_evt_send(sdev, evt); | |
2311 | } | |
2312 | EXPORT_SYMBOL_GPL(sdev_evt_send_simple); | |
2313 | ||
2314 | /** | |
2315 | * scsi_device_quiesce - Block user issued commands. | |
2316 | * @sdev: scsi device to quiesce. | |
2317 | * | |
2318 | * This works by trying to transition to the SDEV_QUIESCE state | |
2319 | * (which must be a legal transition). When the device is in this | |
2320 | * state, only special requests will be accepted, all others will | |
2321 | * be deferred. Since special requests may also be requeued requests, | |
2322 | * a successful return doesn't guarantee the device will be | |
2323 | * totally quiescent. | |
2324 | * | |
2325 | * Must be called with user context, may sleep. | |
2326 | * | |
2327 | * Returns zero if unsuccessful or an error if not. | |
2328 | */ | |
2329 | int | |
2330 | scsi_device_quiesce(struct scsi_device *sdev) | |
2331 | { | |
2332 | int err = scsi_device_set_state(sdev, SDEV_QUIESCE); | |
2333 | if (err) | |
2334 | return err; | |
2335 | ||
2336 | scsi_run_queue(sdev->request_queue); | |
2337 | while (sdev->device_busy) { | |
2338 | msleep_interruptible(200); | |
2339 | scsi_run_queue(sdev->request_queue); | |
2340 | } | |
2341 | return 0; | |
2342 | } | |
2343 | EXPORT_SYMBOL(scsi_device_quiesce); | |
2344 | ||
2345 | /** | |
2346 | * scsi_device_resume - Restart user issued commands to a quiesced device. | |
2347 | * @sdev: scsi device to resume. | |
2348 | * | |
2349 | * Moves the device from quiesced back to running and restarts the | |
2350 | * queues. | |
2351 | * | |
2352 | * Must be called with user context, may sleep. | |
2353 | */ | |
2354 | void scsi_device_resume(struct scsi_device *sdev) | |
2355 | { | |
2356 | /* check if the device state was mutated prior to resume, and if | |
2357 | * so assume the state is being managed elsewhere (for example | |
2358 | * device deleted during suspend) | |
2359 | */ | |
2360 | if (sdev->sdev_state != SDEV_QUIESCE || | |
2361 | scsi_device_set_state(sdev, SDEV_RUNNING)) | |
2362 | return; | |
2363 | scsi_run_queue(sdev->request_queue); | |
2364 | } | |
2365 | EXPORT_SYMBOL(scsi_device_resume); | |
2366 | ||
2367 | static void | |
2368 | device_quiesce_fn(struct scsi_device *sdev, void *data) | |
2369 | { | |
2370 | scsi_device_quiesce(sdev); | |
2371 | } | |
2372 | ||
2373 | void | |
2374 | scsi_target_quiesce(struct scsi_target *starget) | |
2375 | { | |
2376 | starget_for_each_device(starget, NULL, device_quiesce_fn); | |
2377 | } | |
2378 | EXPORT_SYMBOL(scsi_target_quiesce); | |
2379 | ||
2380 | static void | |
2381 | device_resume_fn(struct scsi_device *sdev, void *data) | |
2382 | { | |
2383 | scsi_device_resume(sdev); | |
2384 | } | |
2385 | ||
2386 | void | |
2387 | scsi_target_resume(struct scsi_target *starget) | |
2388 | { | |
2389 | starget_for_each_device(starget, NULL, device_resume_fn); | |
2390 | } | |
2391 | EXPORT_SYMBOL(scsi_target_resume); | |
2392 | ||
2393 | /** | |
2394 | * scsi_internal_device_block - internal function to put a device temporarily into the SDEV_BLOCK state | |
2395 | * @sdev: device to block | |
2396 | * | |
2397 | * Block request made by scsi lld's to temporarily stop all | |
2398 | * scsi commands on the specified device. Called from interrupt | |
2399 | * or normal process context. | |
2400 | * | |
2401 | * Returns zero if successful or error if not | |
2402 | * | |
2403 | * Notes: | |
2404 | * This routine transitions the device to the SDEV_BLOCK state | |
2405 | * (which must be a legal transition). When the device is in this | |
2406 | * state, all commands are deferred until the scsi lld reenables | |
2407 | * the device with scsi_device_unblock or device_block_tmo fires. | |
2408 | * This routine assumes the host_lock is held on entry. | |
2409 | */ | |
2410 | int | |
2411 | scsi_internal_device_block(struct scsi_device *sdev) | |
2412 | { | |
2413 | struct request_queue *q = sdev->request_queue; | |
2414 | unsigned long flags; | |
2415 | int err = 0; | |
2416 | ||
2417 | err = scsi_device_set_state(sdev, SDEV_BLOCK); | |
2418 | if (err) { | |
2419 | err = scsi_device_set_state(sdev, SDEV_CREATED_BLOCK); | |
2420 | ||
2421 | if (err) | |
2422 | return err; | |
2423 | } | |
2424 | ||
2425 | /* | |
2426 | * The device has transitioned to SDEV_BLOCK. Stop the | |
2427 | * block layer from calling the midlayer with this device's | |
2428 | * request queue. | |
2429 | */ | |
2430 | spin_lock_irqsave(q->queue_lock, flags); | |
2431 | blk_stop_queue(q); | |
2432 | spin_unlock_irqrestore(q->queue_lock, flags); | |
2433 | ||
2434 | return 0; | |
2435 | } | |
2436 | EXPORT_SYMBOL_GPL(scsi_internal_device_block); | |
2437 | ||
2438 | /** | |
2439 | * scsi_internal_device_unblock - resume a device after a block request | |
2440 | * @sdev: device to resume | |
2441 | * | |
2442 | * Called by scsi lld's or the midlayer to restart the device queue | |
2443 | * for the previously suspended scsi device. Called from interrupt or | |
2444 | * normal process context. | |
2445 | * | |
2446 | * Returns zero if successful or error if not. | |
2447 | * | |
2448 | * Notes: | |
2449 | * This routine transitions the device to the SDEV_RUNNING state | |
2450 | * (which must be a legal transition) allowing the midlayer to | |
2451 | * goose the queue for this device. This routine assumes the | |
2452 | * host_lock is held upon entry. | |
2453 | */ | |
2454 | int | |
2455 | scsi_internal_device_unblock(struct scsi_device *sdev) | |
2456 | { | |
2457 | struct request_queue *q = sdev->request_queue; | |
2458 | unsigned long flags; | |
2459 | ||
2460 | /* | |
2461 | * Try to transition the scsi device to SDEV_RUNNING | |
2462 | * and goose the device queue if successful. | |
2463 | */ | |
2464 | if (sdev->sdev_state == SDEV_BLOCK) | |
2465 | sdev->sdev_state = SDEV_RUNNING; | |
2466 | else if (sdev->sdev_state == SDEV_CREATED_BLOCK) | |
2467 | sdev->sdev_state = SDEV_CREATED; | |
2468 | else if (sdev->sdev_state != SDEV_CANCEL && | |
2469 | sdev->sdev_state != SDEV_OFFLINE) | |
2470 | return -EINVAL; | |
2471 | ||
2472 | spin_lock_irqsave(q->queue_lock, flags); | |
2473 | blk_start_queue(q); | |
2474 | spin_unlock_irqrestore(q->queue_lock, flags); | |
2475 | ||
2476 | return 0; | |
2477 | } | |
2478 | EXPORT_SYMBOL_GPL(scsi_internal_device_unblock); | |
2479 | ||
2480 | static void | |
2481 | device_block(struct scsi_device *sdev, void *data) | |
2482 | { | |
2483 | scsi_internal_device_block(sdev); | |
2484 | } | |
2485 | ||
2486 | static int | |
2487 | target_block(struct device *dev, void *data) | |
2488 | { | |
2489 | if (scsi_is_target_device(dev)) | |
2490 | starget_for_each_device(to_scsi_target(dev), NULL, | |
2491 | device_block); | |
2492 | return 0; | |
2493 | } | |
2494 | ||
2495 | void | |
2496 | scsi_target_block(struct device *dev) | |
2497 | { | |
2498 | if (scsi_is_target_device(dev)) | |
2499 | starget_for_each_device(to_scsi_target(dev), NULL, | |
2500 | device_block); | |
2501 | else | |
2502 | device_for_each_child(dev, NULL, target_block); | |
2503 | } | |
2504 | EXPORT_SYMBOL_GPL(scsi_target_block); | |
2505 | ||
2506 | static void | |
2507 | device_unblock(struct scsi_device *sdev, void *data) | |
2508 | { | |
2509 | scsi_internal_device_unblock(sdev); | |
2510 | } | |
2511 | ||
2512 | static int | |
2513 | target_unblock(struct device *dev, void *data) | |
2514 | { | |
2515 | if (scsi_is_target_device(dev)) | |
2516 | starget_for_each_device(to_scsi_target(dev), NULL, | |
2517 | device_unblock); | |
2518 | return 0; | |
2519 | } | |
2520 | ||
2521 | void | |
2522 | scsi_target_unblock(struct device *dev) | |
2523 | { | |
2524 | if (scsi_is_target_device(dev)) | |
2525 | starget_for_each_device(to_scsi_target(dev), NULL, | |
2526 | device_unblock); | |
2527 | else | |
2528 | device_for_each_child(dev, NULL, target_unblock); | |
2529 | } | |
2530 | EXPORT_SYMBOL_GPL(scsi_target_unblock); | |
2531 | ||
2532 | /** | |
2533 | * scsi_kmap_atomic_sg - find and atomically map an sg-elemnt | |
2534 | * @sgl: scatter-gather list | |
2535 | * @sg_count: number of segments in sg | |
2536 | * @offset: offset in bytes into sg, on return offset into the mapped area | |
2537 | * @len: bytes to map, on return number of bytes mapped | |
2538 | * | |
2539 | * Returns virtual address of the start of the mapped page | |
2540 | */ | |
2541 | void *scsi_kmap_atomic_sg(struct scatterlist *sgl, int sg_count, | |
2542 | size_t *offset, size_t *len) | |
2543 | { | |
2544 | int i; | |
2545 | size_t sg_len = 0, len_complete = 0; | |
2546 | struct scatterlist *sg; | |
2547 | struct page *page; | |
2548 | ||
2549 | WARN_ON(!irqs_disabled()); | |
2550 | ||
2551 | for_each_sg(sgl, sg, sg_count, i) { | |
2552 | len_complete = sg_len; /* Complete sg-entries */ | |
2553 | sg_len += sg->length; | |
2554 | if (sg_len > *offset) | |
2555 | break; | |
2556 | } | |
2557 | ||
2558 | if (unlikely(i == sg_count)) { | |
2559 | printk(KERN_ERR "%s: Bytes in sg: %zu, requested offset %zu, " | |
2560 | "elements %d\n", | |
2561 | __func__, sg_len, *offset, sg_count); | |
2562 | WARN_ON(1); | |
2563 | return NULL; | |
2564 | } | |
2565 | ||
2566 | /* Offset starting from the beginning of first page in this sg-entry */ | |
2567 | *offset = *offset - len_complete + sg->offset; | |
2568 | ||
2569 | /* Assumption: contiguous pages can be accessed as "page + i" */ | |
2570 | page = nth_page(sg_page(sg), (*offset >> PAGE_SHIFT)); | |
2571 | *offset &= ~PAGE_MASK; | |
2572 | ||
2573 | /* Bytes in this sg-entry from *offset to the end of the page */ | |
2574 | sg_len = PAGE_SIZE - *offset; | |
2575 | if (*len > sg_len) | |
2576 | *len = sg_len; | |
2577 | ||
2578 | return kmap_atomic(page); | |
2579 | } | |
2580 | EXPORT_SYMBOL(scsi_kmap_atomic_sg); | |
2581 | ||
2582 | /** | |
2583 | * scsi_kunmap_atomic_sg - atomically unmap a virtual address, previously mapped with scsi_kmap_atomic_sg | |
2584 | * @virt: virtual address to be unmapped | |
2585 | */ | |
2586 | void scsi_kunmap_atomic_sg(void *virt) | |
2587 | { | |
2588 | kunmap_atomic(virt); | |
2589 | } | |
2590 | EXPORT_SYMBOL(scsi_kunmap_atomic_sg); |