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1da177e4 LT |
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/blkdev.h> | |
12 | #include <linux/completion.h> | |
13 | #include <linux/kernel.h> | |
14 | #include <linux/mempool.h> | |
15 | #include <linux/slab.h> | |
16 | #include <linux/init.h> | |
17 | #include <linux/pci.h> | |
18 | #include <linux/delay.h> | |
19 | ||
20 | #include <scsi/scsi.h> | |
21 | #include <scsi/scsi_dbg.h> | |
22 | #include <scsi/scsi_device.h> | |
23 | #include <scsi/scsi_driver.h> | |
24 | #include <scsi/scsi_eh.h> | |
25 | #include <scsi/scsi_host.h> | |
26 | #include <scsi/scsi_request.h> | |
27 | ||
28 | #include "scsi_priv.h" | |
29 | #include "scsi_logging.h" | |
30 | ||
31 | ||
32 | #define SG_MEMPOOL_NR (sizeof(scsi_sg_pools)/sizeof(struct scsi_host_sg_pool)) | |
33 | #define SG_MEMPOOL_SIZE 32 | |
34 | ||
35 | struct scsi_host_sg_pool { | |
36 | size_t size; | |
37 | char *name; | |
38 | kmem_cache_t *slab; | |
39 | mempool_t *pool; | |
40 | }; | |
41 | ||
42 | #if (SCSI_MAX_PHYS_SEGMENTS < 32) | |
43 | #error SCSI_MAX_PHYS_SEGMENTS is too small | |
44 | #endif | |
45 | ||
46 | #define SP(x) { x, "sgpool-" #x } | |
52c1da39 | 47 | static struct scsi_host_sg_pool scsi_sg_pools[] = { |
1da177e4 LT |
48 | SP(8), |
49 | SP(16), | |
50 | SP(32), | |
51 | #if (SCSI_MAX_PHYS_SEGMENTS > 32) | |
52 | SP(64), | |
53 | #if (SCSI_MAX_PHYS_SEGMENTS > 64) | |
54 | SP(128), | |
55 | #if (SCSI_MAX_PHYS_SEGMENTS > 128) | |
56 | SP(256), | |
57 | #if (SCSI_MAX_PHYS_SEGMENTS > 256) | |
58 | #error SCSI_MAX_PHYS_SEGMENTS is too large | |
59 | #endif | |
60 | #endif | |
61 | #endif | |
62 | #endif | |
63 | }; | |
64 | #undef SP | |
65 | ||
66 | ||
67 | /* | |
68 | * Function: scsi_insert_special_req() | |
69 | * | |
70 | * Purpose: Insert pre-formed request into request queue. | |
71 | * | |
72 | * Arguments: sreq - request that is ready to be queued. | |
73 | * at_head - boolean. True if we should insert at head | |
74 | * of queue, false if we should insert at tail. | |
75 | * | |
76 | * Lock status: Assumed that lock is not held upon entry. | |
77 | * | |
78 | * Returns: Nothing | |
79 | * | |
80 | * Notes: This function is called from character device and from | |
81 | * ioctl types of functions where the caller knows exactly | |
82 | * what SCSI command needs to be issued. The idea is that | |
83 | * we merely inject the command into the queue (at the head | |
84 | * for now), and then call the queue request function to actually | |
85 | * process it. | |
86 | */ | |
87 | int scsi_insert_special_req(struct scsi_request *sreq, int at_head) | |
88 | { | |
89 | /* | |
90 | * Because users of this function are apt to reuse requests with no | |
91 | * modification, we have to sanitise the request flags here | |
92 | */ | |
93 | sreq->sr_request->flags &= ~REQ_DONTPREP; | |
94 | blk_insert_request(sreq->sr_device->request_queue, sreq->sr_request, | |
867d1191 | 95 | at_head, sreq); |
1da177e4 LT |
96 | return 0; |
97 | } | |
98 | ||
a1bf9d1d TH |
99 | static void scsi_run_queue(struct request_queue *q); |
100 | ||
1da177e4 LT |
101 | /* |
102 | * Function: scsi_queue_insert() | |
103 | * | |
104 | * Purpose: Insert a command in the midlevel queue. | |
105 | * | |
106 | * Arguments: cmd - command that we are adding to queue. | |
107 | * reason - why we are inserting command to queue. | |
108 | * | |
109 | * Lock status: Assumed that lock is not held upon entry. | |
110 | * | |
111 | * Returns: Nothing. | |
112 | * | |
113 | * Notes: We do this for one of two cases. Either the host is busy | |
114 | * and it cannot accept any more commands for the time being, | |
115 | * or the device returned QUEUE_FULL and can accept no more | |
116 | * commands. | |
117 | * Notes: This could be called either from an interrupt context or a | |
118 | * normal process context. | |
119 | */ | |
120 | int scsi_queue_insert(struct scsi_cmnd *cmd, int reason) | |
121 | { | |
122 | struct Scsi_Host *host = cmd->device->host; | |
123 | struct scsi_device *device = cmd->device; | |
a1bf9d1d TH |
124 | struct request_queue *q = device->request_queue; |
125 | unsigned long flags; | |
1da177e4 LT |
126 | |
127 | SCSI_LOG_MLQUEUE(1, | |
128 | printk("Inserting command %p into mlqueue\n", cmd)); | |
129 | ||
130 | /* | |
d8c37e7b | 131 | * Set the appropriate busy bit for the device/host. |
1da177e4 LT |
132 | * |
133 | * If the host/device isn't busy, assume that something actually | |
134 | * completed, and that we should be able to queue a command now. | |
135 | * | |
136 | * Note that the prior mid-layer assumption that any host could | |
137 | * always queue at least one command is now broken. The mid-layer | |
138 | * will implement a user specifiable stall (see | |
139 | * scsi_host.max_host_blocked and scsi_device.max_device_blocked) | |
140 | * if a command is requeued with no other commands outstanding | |
141 | * either for the device or for the host. | |
142 | */ | |
143 | if (reason == SCSI_MLQUEUE_HOST_BUSY) | |
144 | host->host_blocked = host->max_host_blocked; | |
145 | else if (reason == SCSI_MLQUEUE_DEVICE_BUSY) | |
146 | device->device_blocked = device->max_device_blocked; | |
147 | ||
148 | /* | |
149 | * Register the fact that we own the thing for now. | |
150 | */ | |
151 | cmd->state = SCSI_STATE_MLQUEUE; | |
152 | cmd->owner = SCSI_OWNER_MIDLEVEL; | |
153 | ||
154 | /* | |
155 | * Decrement the counters, since these commands are no longer | |
156 | * active on the host/device. | |
157 | */ | |
158 | scsi_device_unbusy(device); | |
159 | ||
160 | /* | |
a1bf9d1d TH |
161 | * Requeue this command. It will go before all other commands |
162 | * that are already in the queue. | |
1da177e4 LT |
163 | * |
164 | * NOTE: there is magic here about the way the queue is plugged if | |
165 | * we have no outstanding commands. | |
166 | * | |
a1bf9d1d | 167 | * Although we *don't* plug the queue, we call the request |
1da177e4 LT |
168 | * function. The SCSI request function detects the blocked condition |
169 | * and plugs the queue appropriately. | |
a1bf9d1d TH |
170 | */ |
171 | spin_lock_irqsave(q->queue_lock, flags); | |
172 | blk_requeue_request(q, cmd->request); | |
173 | spin_unlock_irqrestore(q->queue_lock, flags); | |
174 | ||
175 | scsi_run_queue(q); | |
176 | ||
1da177e4 LT |
177 | return 0; |
178 | } | |
179 | ||
180 | /* | |
181 | * Function: scsi_do_req | |
182 | * | |
183 | * Purpose: Queue a SCSI request | |
184 | * | |
185 | * Arguments: sreq - command descriptor. | |
186 | * cmnd - actual SCSI command to be performed. | |
187 | * buffer - data buffer. | |
188 | * bufflen - size of data buffer. | |
189 | * done - completion function to be run. | |
190 | * timeout - how long to let it run before timeout. | |
191 | * retries - number of retries we allow. | |
192 | * | |
193 | * Lock status: No locks held upon entry. | |
194 | * | |
195 | * Returns: Nothing. | |
196 | * | |
197 | * Notes: This function is only used for queueing requests for things | |
198 | * like ioctls and character device requests - this is because | |
199 | * we essentially just inject a request into the queue for the | |
200 | * device. | |
201 | * | |
202 | * In order to support the scsi_device_quiesce function, we | |
203 | * now inject requests on the *head* of the device queue | |
204 | * rather than the tail. | |
205 | */ | |
206 | void scsi_do_req(struct scsi_request *sreq, const void *cmnd, | |
207 | void *buffer, unsigned bufflen, | |
208 | void (*done)(struct scsi_cmnd *), | |
209 | int timeout, int retries) | |
210 | { | |
211 | /* | |
212 | * If the upper level driver is reusing these things, then | |
213 | * we should release the low-level block now. Another one will | |
214 | * be allocated later when this request is getting queued. | |
215 | */ | |
216 | __scsi_release_request(sreq); | |
217 | ||
218 | /* | |
219 | * Our own function scsi_done (which marks the host as not busy, | |
220 | * disables the timeout counter, etc) will be called by us or by the | |
221 | * scsi_hosts[host].queuecommand() function needs to also call | |
222 | * the completion function for the high level driver. | |
223 | */ | |
224 | memcpy(sreq->sr_cmnd, cmnd, sizeof(sreq->sr_cmnd)); | |
225 | sreq->sr_bufflen = bufflen; | |
226 | sreq->sr_buffer = buffer; | |
227 | sreq->sr_allowed = retries; | |
228 | sreq->sr_done = done; | |
229 | sreq->sr_timeout_per_command = timeout; | |
230 | ||
231 | if (sreq->sr_cmd_len == 0) | |
232 | sreq->sr_cmd_len = COMMAND_SIZE(sreq->sr_cmnd[0]); | |
233 | ||
234 | /* | |
235 | * head injection *required* here otherwise quiesce won't work | |
236 | */ | |
237 | scsi_insert_special_req(sreq, 1); | |
238 | } | |
239 | EXPORT_SYMBOL(scsi_do_req); | |
240 | ||
241 | static void scsi_wait_done(struct scsi_cmnd *cmd) | |
242 | { | |
243 | struct request *req = cmd->request; | |
244 | struct request_queue *q = cmd->device->request_queue; | |
245 | unsigned long flags; | |
246 | ||
247 | req->rq_status = RQ_SCSI_DONE; /* Busy, but indicate request done */ | |
248 | ||
249 | spin_lock_irqsave(q->queue_lock, flags); | |
250 | if (blk_rq_tagged(req)) | |
251 | blk_queue_end_tag(q, req); | |
252 | spin_unlock_irqrestore(q->queue_lock, flags); | |
253 | ||
254 | if (req->waiting) | |
255 | complete(req->waiting); | |
256 | } | |
257 | ||
258 | /* This is the end routine we get to if a command was never attached | |
259 | * to the request. Simply complete the request without changing | |
260 | * rq_status; this will cause a DRIVER_ERROR. */ | |
261 | static void scsi_wait_req_end_io(struct request *req) | |
262 | { | |
263 | BUG_ON(!req->waiting); | |
264 | ||
265 | complete(req->waiting); | |
266 | } | |
267 | ||
268 | void scsi_wait_req(struct scsi_request *sreq, const void *cmnd, void *buffer, | |
269 | unsigned bufflen, int timeout, int retries) | |
270 | { | |
271 | DECLARE_COMPLETION(wait); | |
272 | ||
273 | sreq->sr_request->waiting = &wait; | |
274 | sreq->sr_request->rq_status = RQ_SCSI_BUSY; | |
275 | sreq->sr_request->end_io = scsi_wait_req_end_io; | |
276 | scsi_do_req(sreq, cmnd, buffer, bufflen, scsi_wait_done, | |
277 | timeout, retries); | |
278 | wait_for_completion(&wait); | |
279 | sreq->sr_request->waiting = NULL; | |
280 | if (sreq->sr_request->rq_status != RQ_SCSI_DONE) | |
281 | sreq->sr_result |= (DRIVER_ERROR << 24); | |
282 | ||
283 | __scsi_release_request(sreq); | |
284 | } | |
285 | EXPORT_SYMBOL(scsi_wait_req); | |
286 | ||
287 | /* | |
288 | * Function: scsi_init_cmd_errh() | |
289 | * | |
290 | * Purpose: Initialize cmd fields related to error handling. | |
291 | * | |
292 | * Arguments: cmd - command that is ready to be queued. | |
293 | * | |
294 | * Returns: Nothing | |
295 | * | |
296 | * Notes: This function has the job of initializing a number of | |
297 | * fields related to error handling. Typically this will | |
298 | * be called once for each command, as required. | |
299 | */ | |
300 | static int scsi_init_cmd_errh(struct scsi_cmnd *cmd) | |
301 | { | |
302 | cmd->owner = SCSI_OWNER_MIDLEVEL; | |
303 | cmd->serial_number = 0; | |
1da177e4 LT |
304 | cmd->abort_reason = 0; |
305 | ||
306 | memset(cmd->sense_buffer, 0, sizeof cmd->sense_buffer); | |
307 | ||
308 | if (cmd->cmd_len == 0) | |
309 | cmd->cmd_len = COMMAND_SIZE(cmd->cmnd[0]); | |
310 | ||
311 | /* | |
312 | * We need saved copies of a number of fields - this is because | |
313 | * error handling may need to overwrite these with different values | |
314 | * to run different commands, and once error handling is complete, | |
315 | * we will need to restore these values prior to running the actual | |
316 | * command. | |
317 | */ | |
318 | cmd->old_use_sg = cmd->use_sg; | |
319 | cmd->old_cmd_len = cmd->cmd_len; | |
320 | cmd->sc_old_data_direction = cmd->sc_data_direction; | |
321 | cmd->old_underflow = cmd->underflow; | |
322 | memcpy(cmd->data_cmnd, cmd->cmnd, sizeof(cmd->cmnd)); | |
323 | cmd->buffer = cmd->request_buffer; | |
324 | cmd->bufflen = cmd->request_bufflen; | |
1da177e4 LT |
325 | cmd->abort_reason = 0; |
326 | ||
327 | return 1; | |
328 | } | |
329 | ||
330 | /* | |
331 | * Function: scsi_setup_cmd_retry() | |
332 | * | |
333 | * Purpose: Restore the command state for a retry | |
334 | * | |
335 | * Arguments: cmd - command to be restored | |
336 | * | |
337 | * Returns: Nothing | |
338 | * | |
339 | * Notes: Immediately prior to retrying a command, we need | |
340 | * to restore certain fields that we saved above. | |
341 | */ | |
342 | void scsi_setup_cmd_retry(struct scsi_cmnd *cmd) | |
343 | { | |
344 | memcpy(cmd->cmnd, cmd->data_cmnd, sizeof(cmd->data_cmnd)); | |
345 | cmd->request_buffer = cmd->buffer; | |
346 | cmd->request_bufflen = cmd->bufflen; | |
347 | cmd->use_sg = cmd->old_use_sg; | |
348 | cmd->cmd_len = cmd->old_cmd_len; | |
349 | cmd->sc_data_direction = cmd->sc_old_data_direction; | |
350 | cmd->underflow = cmd->old_underflow; | |
351 | } | |
352 | ||
353 | void scsi_device_unbusy(struct scsi_device *sdev) | |
354 | { | |
355 | struct Scsi_Host *shost = sdev->host; | |
356 | unsigned long flags; | |
357 | ||
358 | spin_lock_irqsave(shost->host_lock, flags); | |
359 | shost->host_busy--; | |
360 | if (unlikely(test_bit(SHOST_RECOVERY, &shost->shost_state) && | |
361 | shost->host_failed)) | |
362 | scsi_eh_wakeup(shost); | |
363 | spin_unlock(shost->host_lock); | |
152587de | 364 | spin_lock(sdev->request_queue->queue_lock); |
1da177e4 | 365 | sdev->device_busy--; |
152587de | 366 | spin_unlock_irqrestore(sdev->request_queue->queue_lock, flags); |
1da177e4 LT |
367 | } |
368 | ||
369 | /* | |
370 | * Called for single_lun devices on IO completion. Clear starget_sdev_user, | |
371 | * and call blk_run_queue for all the scsi_devices on the target - | |
372 | * including current_sdev first. | |
373 | * | |
374 | * Called with *no* scsi locks held. | |
375 | */ | |
376 | static void scsi_single_lun_run(struct scsi_device *current_sdev) | |
377 | { | |
378 | struct Scsi_Host *shost = current_sdev->host; | |
379 | struct scsi_device *sdev, *tmp; | |
380 | struct scsi_target *starget = scsi_target(current_sdev); | |
381 | unsigned long flags; | |
382 | ||
383 | spin_lock_irqsave(shost->host_lock, flags); | |
384 | starget->starget_sdev_user = NULL; | |
385 | spin_unlock_irqrestore(shost->host_lock, flags); | |
386 | ||
387 | /* | |
388 | * Call blk_run_queue for all LUNs on the target, starting with | |
389 | * current_sdev. We race with others (to set starget_sdev_user), | |
390 | * but in most cases, we will be first. Ideally, each LU on the | |
391 | * target would get some limited time or requests on the target. | |
392 | */ | |
393 | blk_run_queue(current_sdev->request_queue); | |
394 | ||
395 | spin_lock_irqsave(shost->host_lock, flags); | |
396 | if (starget->starget_sdev_user) | |
397 | goto out; | |
398 | list_for_each_entry_safe(sdev, tmp, &starget->devices, | |
399 | same_target_siblings) { | |
400 | if (sdev == current_sdev) | |
401 | continue; | |
402 | if (scsi_device_get(sdev)) | |
403 | continue; | |
404 | ||
405 | spin_unlock_irqrestore(shost->host_lock, flags); | |
406 | blk_run_queue(sdev->request_queue); | |
407 | spin_lock_irqsave(shost->host_lock, flags); | |
408 | ||
409 | scsi_device_put(sdev); | |
410 | } | |
411 | out: | |
412 | spin_unlock_irqrestore(shost->host_lock, flags); | |
413 | } | |
414 | ||
415 | /* | |
416 | * Function: scsi_run_queue() | |
417 | * | |
418 | * Purpose: Select a proper request queue to serve next | |
419 | * | |
420 | * Arguments: q - last request's queue | |
421 | * | |
422 | * Returns: Nothing | |
423 | * | |
424 | * Notes: The previous command was completely finished, start | |
425 | * a new one if possible. | |
426 | */ | |
427 | static void scsi_run_queue(struct request_queue *q) | |
428 | { | |
429 | struct scsi_device *sdev = q->queuedata; | |
430 | struct Scsi_Host *shost = sdev->host; | |
431 | unsigned long flags; | |
432 | ||
433 | if (sdev->single_lun) | |
434 | scsi_single_lun_run(sdev); | |
435 | ||
436 | spin_lock_irqsave(shost->host_lock, flags); | |
437 | while (!list_empty(&shost->starved_list) && | |
438 | !shost->host_blocked && !shost->host_self_blocked && | |
439 | !((shost->can_queue > 0) && | |
440 | (shost->host_busy >= shost->can_queue))) { | |
441 | /* | |
442 | * As long as shost is accepting commands and we have | |
443 | * starved queues, call blk_run_queue. scsi_request_fn | |
444 | * drops the queue_lock and can add us back to the | |
445 | * starved_list. | |
446 | * | |
447 | * host_lock protects the starved_list and starved_entry. | |
448 | * scsi_request_fn must get the host_lock before checking | |
449 | * or modifying starved_list or starved_entry. | |
450 | */ | |
451 | sdev = list_entry(shost->starved_list.next, | |
452 | struct scsi_device, starved_entry); | |
453 | list_del_init(&sdev->starved_entry); | |
454 | spin_unlock_irqrestore(shost->host_lock, flags); | |
455 | ||
456 | blk_run_queue(sdev->request_queue); | |
457 | ||
458 | spin_lock_irqsave(shost->host_lock, flags); | |
459 | if (unlikely(!list_empty(&sdev->starved_entry))) | |
460 | /* | |
461 | * sdev lost a race, and was put back on the | |
462 | * starved list. This is unlikely but without this | |
463 | * in theory we could loop forever. | |
464 | */ | |
465 | break; | |
466 | } | |
467 | spin_unlock_irqrestore(shost->host_lock, flags); | |
468 | ||
469 | blk_run_queue(q); | |
470 | } | |
471 | ||
472 | /* | |
473 | * Function: scsi_requeue_command() | |
474 | * | |
475 | * Purpose: Handle post-processing of completed commands. | |
476 | * | |
477 | * Arguments: q - queue to operate on | |
478 | * cmd - command that may need to be requeued. | |
479 | * | |
480 | * Returns: Nothing | |
481 | * | |
482 | * Notes: After command completion, there may be blocks left | |
483 | * over which weren't finished by the previous command | |
484 | * this can be for a number of reasons - the main one is | |
485 | * I/O errors in the middle of the request, in which case | |
486 | * we need to request the blocks that come after the bad | |
487 | * sector. | |
488 | */ | |
489 | static void scsi_requeue_command(struct request_queue *q, struct scsi_cmnd *cmd) | |
490 | { | |
283369cc TH |
491 | unsigned long flags; |
492 | ||
1da177e4 | 493 | cmd->request->flags &= ~REQ_DONTPREP; |
283369cc TH |
494 | |
495 | spin_lock_irqsave(q->queue_lock, flags); | |
496 | blk_requeue_request(q, cmd->request); | |
497 | spin_unlock_irqrestore(q->queue_lock, flags); | |
1da177e4 LT |
498 | |
499 | scsi_run_queue(q); | |
500 | } | |
501 | ||
502 | void scsi_next_command(struct scsi_cmnd *cmd) | |
503 | { | |
504 | struct request_queue *q = cmd->device->request_queue; | |
505 | ||
506 | scsi_put_command(cmd); | |
507 | scsi_run_queue(q); | |
508 | } | |
509 | ||
510 | void scsi_run_host_queues(struct Scsi_Host *shost) | |
511 | { | |
512 | struct scsi_device *sdev; | |
513 | ||
514 | shost_for_each_device(sdev, shost) | |
515 | scsi_run_queue(sdev->request_queue); | |
516 | } | |
517 | ||
518 | /* | |
519 | * Function: scsi_end_request() | |
520 | * | |
521 | * Purpose: Post-processing of completed commands (usually invoked at end | |
522 | * of upper level post-processing and scsi_io_completion). | |
523 | * | |
524 | * Arguments: cmd - command that is complete. | |
525 | * uptodate - 1 if I/O indicates success, <= 0 for I/O error. | |
526 | * bytes - number of bytes of completed I/O | |
527 | * requeue - indicates whether we should requeue leftovers. | |
528 | * | |
529 | * Lock status: Assumed that lock is not held upon entry. | |
530 | * | |
531 | * Returns: cmd if requeue done or required, NULL otherwise | |
532 | * | |
533 | * Notes: This is called for block device requests in order to | |
534 | * mark some number of sectors as complete. | |
535 | * | |
536 | * We are guaranteeing that the request queue will be goosed | |
537 | * at some point during this call. | |
538 | */ | |
539 | static struct scsi_cmnd *scsi_end_request(struct scsi_cmnd *cmd, int uptodate, | |
540 | int bytes, int requeue) | |
541 | { | |
542 | request_queue_t *q = cmd->device->request_queue; | |
543 | struct request *req = cmd->request; | |
544 | unsigned long flags; | |
545 | ||
546 | /* | |
547 | * If there are blocks left over at the end, set up the command | |
548 | * to queue the remainder of them. | |
549 | */ | |
550 | if (end_that_request_chunk(req, uptodate, bytes)) { | |
551 | int leftover = (req->hard_nr_sectors << 9); | |
552 | ||
553 | if (blk_pc_request(req)) | |
554 | leftover = req->data_len; | |
555 | ||
556 | /* kill remainder if no retrys */ | |
557 | if (!uptodate && blk_noretry_request(req)) | |
558 | end_that_request_chunk(req, 0, leftover); | |
559 | else { | |
560 | if (requeue) | |
561 | /* | |
562 | * Bleah. Leftovers again. Stick the | |
563 | * leftovers in the front of the | |
564 | * queue, and goose the queue again. | |
565 | */ | |
566 | scsi_requeue_command(q, cmd); | |
567 | ||
568 | return cmd; | |
569 | } | |
570 | } | |
571 | ||
572 | add_disk_randomness(req->rq_disk); | |
573 | ||
574 | spin_lock_irqsave(q->queue_lock, flags); | |
575 | if (blk_rq_tagged(req)) | |
576 | blk_queue_end_tag(q, req); | |
577 | end_that_request_last(req); | |
578 | spin_unlock_irqrestore(q->queue_lock, flags); | |
579 | ||
580 | /* | |
581 | * This will goose the queue request function at the end, so we don't | |
582 | * need to worry about launching another command. | |
583 | */ | |
584 | scsi_next_command(cmd); | |
585 | return NULL; | |
586 | } | |
587 | ||
588 | static struct scatterlist *scsi_alloc_sgtable(struct scsi_cmnd *cmd, int gfp_mask) | |
589 | { | |
590 | struct scsi_host_sg_pool *sgp; | |
591 | struct scatterlist *sgl; | |
592 | ||
593 | BUG_ON(!cmd->use_sg); | |
594 | ||
595 | switch (cmd->use_sg) { | |
596 | case 1 ... 8: | |
597 | cmd->sglist_len = 0; | |
598 | break; | |
599 | case 9 ... 16: | |
600 | cmd->sglist_len = 1; | |
601 | break; | |
602 | case 17 ... 32: | |
603 | cmd->sglist_len = 2; | |
604 | break; | |
605 | #if (SCSI_MAX_PHYS_SEGMENTS > 32) | |
606 | case 33 ... 64: | |
607 | cmd->sglist_len = 3; | |
608 | break; | |
609 | #if (SCSI_MAX_PHYS_SEGMENTS > 64) | |
610 | case 65 ... 128: | |
611 | cmd->sglist_len = 4; | |
612 | break; | |
613 | #if (SCSI_MAX_PHYS_SEGMENTS > 128) | |
614 | case 129 ... 256: | |
615 | cmd->sglist_len = 5; | |
616 | break; | |
617 | #endif | |
618 | #endif | |
619 | #endif | |
620 | default: | |
621 | return NULL; | |
622 | } | |
623 | ||
624 | sgp = scsi_sg_pools + cmd->sglist_len; | |
625 | sgl = mempool_alloc(sgp->pool, gfp_mask); | |
626 | if (sgl) | |
627 | memset(sgl, 0, sgp->size); | |
628 | return sgl; | |
629 | } | |
630 | ||
631 | static void scsi_free_sgtable(struct scatterlist *sgl, int index) | |
632 | { | |
633 | struct scsi_host_sg_pool *sgp; | |
634 | ||
635 | BUG_ON(index > SG_MEMPOOL_NR); | |
636 | ||
637 | sgp = scsi_sg_pools + index; | |
638 | mempool_free(sgl, sgp->pool); | |
639 | } | |
640 | ||
641 | /* | |
642 | * Function: scsi_release_buffers() | |
643 | * | |
644 | * Purpose: Completion processing for block device I/O requests. | |
645 | * | |
646 | * Arguments: cmd - command that we are bailing. | |
647 | * | |
648 | * Lock status: Assumed that no lock is held upon entry. | |
649 | * | |
650 | * Returns: Nothing | |
651 | * | |
652 | * Notes: In the event that an upper level driver rejects a | |
653 | * command, we must release resources allocated during | |
654 | * the __init_io() function. Primarily this would involve | |
655 | * the scatter-gather table, and potentially any bounce | |
656 | * buffers. | |
657 | */ | |
658 | static void scsi_release_buffers(struct scsi_cmnd *cmd) | |
659 | { | |
660 | struct request *req = cmd->request; | |
661 | ||
662 | /* | |
663 | * Free up any indirection buffers we allocated for DMA purposes. | |
664 | */ | |
665 | if (cmd->use_sg) | |
666 | scsi_free_sgtable(cmd->request_buffer, cmd->sglist_len); | |
667 | else if (cmd->request_buffer != req->buffer) | |
668 | kfree(cmd->request_buffer); | |
669 | ||
670 | /* | |
671 | * Zero these out. They now point to freed memory, and it is | |
672 | * dangerous to hang onto the pointers. | |
673 | */ | |
674 | cmd->buffer = NULL; | |
675 | cmd->bufflen = 0; | |
676 | cmd->request_buffer = NULL; | |
677 | cmd->request_bufflen = 0; | |
678 | } | |
679 | ||
680 | /* | |
681 | * Function: scsi_io_completion() | |
682 | * | |
683 | * Purpose: Completion processing for block device I/O requests. | |
684 | * | |
685 | * Arguments: cmd - command that is finished. | |
686 | * | |
687 | * Lock status: Assumed that no lock is held upon entry. | |
688 | * | |
689 | * Returns: Nothing | |
690 | * | |
691 | * Notes: This function is matched in terms of capabilities to | |
692 | * the function that created the scatter-gather list. | |
693 | * In other words, if there are no bounce buffers | |
694 | * (the normal case for most drivers), we don't need | |
695 | * the logic to deal with cleaning up afterwards. | |
696 | * | |
697 | * We must do one of several things here: | |
698 | * | |
699 | * a) Call scsi_end_request. This will finish off the | |
700 | * specified number of sectors. If we are done, the | |
701 | * command block will be released, and the queue | |
702 | * function will be goosed. If we are not done, then | |
703 | * scsi_end_request will directly goose the queue. | |
704 | * | |
705 | * b) We can just use scsi_requeue_command() here. This would | |
706 | * be used if we just wanted to retry, for example. | |
707 | */ | |
708 | void scsi_io_completion(struct scsi_cmnd *cmd, unsigned int good_bytes, | |
709 | unsigned int block_bytes) | |
710 | { | |
711 | int result = cmd->result; | |
712 | int this_count = cmd->bufflen; | |
713 | request_queue_t *q = cmd->device->request_queue; | |
714 | struct request *req = cmd->request; | |
715 | int clear_errors = 1; | |
716 | struct scsi_sense_hdr sshdr; | |
717 | int sense_valid = 0; | |
718 | int sense_deferred = 0; | |
719 | ||
720 | if (blk_complete_barrier_rq(q, req, good_bytes >> 9)) | |
721 | return; | |
722 | ||
723 | /* | |
724 | * Free up any indirection buffers we allocated for DMA purposes. | |
725 | * For the case of a READ, we need to copy the data out of the | |
726 | * bounce buffer and into the real buffer. | |
727 | */ | |
728 | if (cmd->use_sg) | |
729 | scsi_free_sgtable(cmd->buffer, cmd->sglist_len); | |
730 | else if (cmd->buffer != req->buffer) { | |
731 | if (rq_data_dir(req) == READ) { | |
732 | unsigned long flags; | |
733 | char *to = bio_kmap_irq(req->bio, &flags); | |
734 | memcpy(to, cmd->buffer, cmd->bufflen); | |
735 | bio_kunmap_irq(to, &flags); | |
736 | } | |
737 | kfree(cmd->buffer); | |
738 | } | |
739 | ||
740 | if (result) { | |
741 | sense_valid = scsi_command_normalize_sense(cmd, &sshdr); | |
742 | if (sense_valid) | |
743 | sense_deferred = scsi_sense_is_deferred(&sshdr); | |
744 | } | |
745 | if (blk_pc_request(req)) { /* SG_IO ioctl from block level */ | |
746 | req->errors = result; | |
747 | if (result) { | |
748 | clear_errors = 0; | |
749 | if (sense_valid && req->sense) { | |
750 | /* | |
751 | * SG_IO wants current and deferred errors | |
752 | */ | |
753 | int len = 8 + cmd->sense_buffer[7]; | |
754 | ||
755 | if (len > SCSI_SENSE_BUFFERSIZE) | |
756 | len = SCSI_SENSE_BUFFERSIZE; | |
757 | memcpy(req->sense, cmd->sense_buffer, len); | |
758 | req->sense_len = len; | |
759 | } | |
760 | } else | |
761 | req->data_len = cmd->resid; | |
762 | } | |
763 | ||
764 | /* | |
765 | * Zero these out. They now point to freed memory, and it is | |
766 | * dangerous to hang onto the pointers. | |
767 | */ | |
768 | cmd->buffer = NULL; | |
769 | cmd->bufflen = 0; | |
770 | cmd->request_buffer = NULL; | |
771 | cmd->request_bufflen = 0; | |
772 | ||
773 | /* | |
774 | * Next deal with any sectors which we were able to correctly | |
775 | * handle. | |
776 | */ | |
777 | if (good_bytes >= 0) { | |
778 | SCSI_LOG_HLCOMPLETE(1, printk("%ld sectors total, %d bytes done.\n", | |
779 | req->nr_sectors, good_bytes)); | |
780 | SCSI_LOG_HLCOMPLETE(1, printk("use_sg is %d\n", cmd->use_sg)); | |
781 | ||
782 | if (clear_errors) | |
783 | req->errors = 0; | |
784 | /* | |
785 | * If multiple sectors are requested in one buffer, then | |
786 | * they will have been finished off by the first command. | |
787 | * If not, then we have a multi-buffer command. | |
788 | * | |
789 | * If block_bytes != 0, it means we had a medium error | |
790 | * of some sort, and that we want to mark some number of | |
791 | * sectors as not uptodate. Thus we want to inhibit | |
792 | * requeueing right here - we will requeue down below | |
793 | * when we handle the bad sectors. | |
794 | */ | |
795 | cmd = scsi_end_request(cmd, 1, good_bytes, result == 0); | |
796 | ||
797 | /* | |
798 | * If the command completed without error, then either finish off the | |
799 | * rest of the command, or start a new one. | |
800 | */ | |
801 | if (result == 0 || cmd == NULL ) { | |
802 | return; | |
803 | } | |
804 | } | |
805 | /* | |
806 | * Now, if we were good little boys and girls, Santa left us a request | |
807 | * sense buffer. We can extract information from this, so we | |
808 | * can choose a block to remap, etc. | |
809 | */ | |
810 | if (sense_valid && !sense_deferred) { | |
811 | switch (sshdr.sense_key) { | |
812 | case UNIT_ATTENTION: | |
813 | if (cmd->device->removable) { | |
814 | /* detected disc change. set a bit | |
815 | * and quietly refuse further access. | |
816 | */ | |
817 | cmd->device->changed = 1; | |
818 | cmd = scsi_end_request(cmd, 0, | |
819 | this_count, 1); | |
820 | return; | |
821 | } else { | |
822 | /* | |
823 | * Must have been a power glitch, or a | |
824 | * bus reset. Could not have been a | |
825 | * media change, so we just retry the | |
826 | * request and see what happens. | |
827 | */ | |
828 | scsi_requeue_command(q, cmd); | |
829 | return; | |
830 | } | |
831 | break; | |
832 | case ILLEGAL_REQUEST: | |
833 | /* | |
834 | * If we had an ILLEGAL REQUEST returned, then we may | |
835 | * have performed an unsupported command. The only | |
836 | * thing this should be would be a ten byte read where | |
837 | * only a six byte read was supported. Also, on a | |
838 | * system where READ CAPACITY failed, we may have read | |
839 | * past the end of the disk. | |
840 | */ | |
841 | if (cmd->device->use_10_for_rw && | |
842 | (cmd->cmnd[0] == READ_10 || | |
843 | cmd->cmnd[0] == WRITE_10)) { | |
844 | cmd->device->use_10_for_rw = 0; | |
845 | /* | |
846 | * This will cause a retry with a 6-byte | |
847 | * command. | |
848 | */ | |
849 | scsi_requeue_command(q, cmd); | |
850 | result = 0; | |
851 | } else { | |
852 | cmd = scsi_end_request(cmd, 0, this_count, 1); | |
853 | return; | |
854 | } | |
855 | break; | |
856 | case NOT_READY: | |
857 | /* | |
858 | * If the device is in the process of becoming ready, | |
859 | * retry. | |
860 | */ | |
861 | if (sshdr.asc == 0x04 && sshdr.ascq == 0x01) { | |
862 | scsi_requeue_command(q, cmd); | |
863 | return; | |
864 | } | |
865 | printk(KERN_INFO "Device %s not ready.\n", | |
866 | req->rq_disk ? req->rq_disk->disk_name : ""); | |
867 | cmd = scsi_end_request(cmd, 0, this_count, 1); | |
868 | return; | |
869 | case VOLUME_OVERFLOW: | |
870 | printk(KERN_INFO "Volume overflow <%d %d %d %d> CDB: ", | |
871 | cmd->device->host->host_no, | |
872 | (int)cmd->device->channel, | |
873 | (int)cmd->device->id, (int)cmd->device->lun); | |
874 | __scsi_print_command(cmd->data_cmnd); | |
875 | scsi_print_sense("", cmd); | |
876 | cmd = scsi_end_request(cmd, 0, block_bytes, 1); | |
877 | return; | |
878 | default: | |
879 | break; | |
880 | } | |
881 | } /* driver byte != 0 */ | |
882 | if (host_byte(result) == DID_RESET) { | |
883 | /* | |
884 | * Third party bus reset or reset for error | |
885 | * recovery reasons. Just retry the request | |
886 | * and see what happens. | |
887 | */ | |
888 | scsi_requeue_command(q, cmd); | |
889 | return; | |
890 | } | |
891 | if (result) { | |
892 | printk(KERN_INFO "SCSI error : <%d %d %d %d> return code " | |
893 | "= 0x%x\n", cmd->device->host->host_no, | |
894 | cmd->device->channel, | |
895 | cmd->device->id, | |
896 | cmd->device->lun, result); | |
897 | ||
898 | if (driver_byte(result) & DRIVER_SENSE) | |
899 | scsi_print_sense("", cmd); | |
900 | /* | |
901 | * Mark a single buffer as not uptodate. Queue the remainder. | |
902 | * We sometimes get this cruft in the event that a medium error | |
903 | * isn't properly reported. | |
904 | */ | |
905 | block_bytes = req->hard_cur_sectors << 9; | |
906 | if (!block_bytes) | |
907 | block_bytes = req->data_len; | |
908 | cmd = scsi_end_request(cmd, 0, block_bytes, 1); | |
909 | } | |
910 | } | |
911 | EXPORT_SYMBOL(scsi_io_completion); | |
912 | ||
913 | /* | |
914 | * Function: scsi_init_io() | |
915 | * | |
916 | * Purpose: SCSI I/O initialize function. | |
917 | * | |
918 | * Arguments: cmd - Command descriptor we wish to initialize | |
919 | * | |
920 | * Returns: 0 on success | |
921 | * BLKPREP_DEFER if the failure is retryable | |
922 | * BLKPREP_KILL if the failure is fatal | |
923 | */ | |
924 | static int scsi_init_io(struct scsi_cmnd *cmd) | |
925 | { | |
926 | struct request *req = cmd->request; | |
927 | struct scatterlist *sgpnt; | |
928 | int count; | |
929 | ||
930 | /* | |
931 | * if this is a rq->data based REQ_BLOCK_PC, setup for a non-sg xfer | |
932 | */ | |
933 | if ((req->flags & REQ_BLOCK_PC) && !req->bio) { | |
934 | cmd->request_bufflen = req->data_len; | |
935 | cmd->request_buffer = req->data; | |
936 | req->buffer = req->data; | |
937 | cmd->use_sg = 0; | |
938 | return 0; | |
939 | } | |
940 | ||
941 | /* | |
942 | * we used to not use scatter-gather for single segment request, | |
943 | * but now we do (it makes highmem I/O easier to support without | |
944 | * kmapping pages) | |
945 | */ | |
946 | cmd->use_sg = req->nr_phys_segments; | |
947 | ||
948 | /* | |
949 | * if sg table allocation fails, requeue request later. | |
950 | */ | |
951 | sgpnt = scsi_alloc_sgtable(cmd, GFP_ATOMIC); | |
beb6617d | 952 | if (unlikely(!sgpnt)) |
1da177e4 | 953 | return BLKPREP_DEFER; |
1da177e4 LT |
954 | |
955 | cmd->request_buffer = (char *) sgpnt; | |
956 | cmd->request_bufflen = req->nr_sectors << 9; | |
957 | if (blk_pc_request(req)) | |
958 | cmd->request_bufflen = req->data_len; | |
959 | req->buffer = NULL; | |
960 | ||
961 | /* | |
962 | * Next, walk the list, and fill in the addresses and sizes of | |
963 | * each segment. | |
964 | */ | |
965 | count = blk_rq_map_sg(req->q, req, cmd->request_buffer); | |
966 | ||
967 | /* | |
968 | * mapped well, send it off | |
969 | */ | |
970 | if (likely(count <= cmd->use_sg)) { | |
971 | cmd->use_sg = count; | |
972 | return 0; | |
973 | } | |
974 | ||
975 | printk(KERN_ERR "Incorrect number of segments after building list\n"); | |
976 | printk(KERN_ERR "counted %d, received %d\n", count, cmd->use_sg); | |
977 | printk(KERN_ERR "req nr_sec %lu, cur_nr_sec %u\n", req->nr_sectors, | |
978 | req->current_nr_sectors); | |
979 | ||
980 | /* release the command and kill it */ | |
981 | scsi_release_buffers(cmd); | |
982 | scsi_put_command(cmd); | |
983 | return BLKPREP_KILL; | |
984 | } | |
985 | ||
986 | static int scsi_prepare_flush_fn(request_queue_t *q, struct request *rq) | |
987 | { | |
988 | struct scsi_device *sdev = q->queuedata; | |
989 | struct scsi_driver *drv; | |
990 | ||
991 | if (sdev->sdev_state == SDEV_RUNNING) { | |
992 | drv = *(struct scsi_driver **) rq->rq_disk->private_data; | |
993 | ||
994 | if (drv->prepare_flush) | |
995 | return drv->prepare_flush(q, rq); | |
996 | } | |
997 | ||
998 | return 0; | |
999 | } | |
1000 | ||
1001 | static void scsi_end_flush_fn(request_queue_t *q, struct request *rq) | |
1002 | { | |
1003 | struct scsi_device *sdev = q->queuedata; | |
1004 | struct request *flush_rq = rq->end_io_data; | |
1005 | struct scsi_driver *drv; | |
1006 | ||
1007 | if (flush_rq->errors) { | |
1008 | printk("scsi: barrier error, disabling flush support\n"); | |
1009 | blk_queue_ordered(q, QUEUE_ORDERED_NONE); | |
1010 | } | |
1011 | ||
1012 | if (sdev->sdev_state == SDEV_RUNNING) { | |
1013 | drv = *(struct scsi_driver **) rq->rq_disk->private_data; | |
1014 | drv->end_flush(q, rq); | |
1015 | } | |
1016 | } | |
1017 | ||
1018 | static int scsi_issue_flush_fn(request_queue_t *q, struct gendisk *disk, | |
1019 | sector_t *error_sector) | |
1020 | { | |
1021 | struct scsi_device *sdev = q->queuedata; | |
1022 | struct scsi_driver *drv; | |
1023 | ||
1024 | if (sdev->sdev_state != SDEV_RUNNING) | |
1025 | return -ENXIO; | |
1026 | ||
1027 | drv = *(struct scsi_driver **) disk->private_data; | |
1028 | if (drv->issue_flush) | |
1029 | return drv->issue_flush(&sdev->sdev_gendev, error_sector); | |
1030 | ||
1031 | return -EOPNOTSUPP; | |
1032 | } | |
1033 | ||
1034 | static int scsi_prep_fn(struct request_queue *q, struct request *req) | |
1035 | { | |
1036 | struct scsi_device *sdev = q->queuedata; | |
1037 | struct scsi_cmnd *cmd; | |
1038 | int specials_only = 0; | |
1039 | ||
1040 | /* | |
1041 | * Just check to see if the device is online. If it isn't, we | |
1042 | * refuse to process any commands. The device must be brought | |
1043 | * online before trying any recovery commands | |
1044 | */ | |
1045 | if (unlikely(!scsi_device_online(sdev))) { | |
1046 | printk(KERN_ERR "scsi%d (%d:%d): rejecting I/O to offline device\n", | |
1047 | sdev->host->host_no, sdev->id, sdev->lun); | |
1048 | return BLKPREP_KILL; | |
1049 | } | |
1050 | if (unlikely(sdev->sdev_state != SDEV_RUNNING)) { | |
1051 | /* OK, we're not in a running state don't prep | |
1052 | * user commands */ | |
1053 | if (sdev->sdev_state == SDEV_DEL) { | |
1054 | /* Device is fully deleted, no commands | |
1055 | * at all allowed down */ | |
1056 | printk(KERN_ERR "scsi%d (%d:%d): rejecting I/O to dead device\n", | |
1057 | sdev->host->host_no, sdev->id, sdev->lun); | |
1058 | return BLKPREP_KILL; | |
1059 | } | |
1060 | /* OK, we only allow special commands (i.e. not | |
1061 | * user initiated ones */ | |
1062 | specials_only = sdev->sdev_state; | |
1063 | } | |
1064 | ||
1065 | /* | |
1066 | * Find the actual device driver associated with this command. | |
1067 | * The SPECIAL requests are things like character device or | |
1068 | * ioctls, which did not originate from ll_rw_blk. Note that | |
1069 | * the special field is also used to indicate the cmd for | |
1070 | * the remainder of a partially fulfilled request that can | |
1071 | * come up when there is a medium error. We have to treat | |
1072 | * these two cases differently. We differentiate by looking | |
1073 | * at request->cmd, as this tells us the real story. | |
1074 | */ | |
1075 | if (req->flags & REQ_SPECIAL) { | |
1076 | struct scsi_request *sreq = req->special; | |
1077 | ||
1078 | if (sreq->sr_magic == SCSI_REQ_MAGIC) { | |
1079 | cmd = scsi_get_command(sreq->sr_device, GFP_ATOMIC); | |
1080 | if (unlikely(!cmd)) | |
1081 | goto defer; | |
1082 | scsi_init_cmd_from_req(cmd, sreq); | |
1083 | } else | |
1084 | cmd = req->special; | |
1085 | } else if (req->flags & (REQ_CMD | REQ_BLOCK_PC)) { | |
1086 | ||
1087 | if(unlikely(specials_only)) { | |
1088 | if(specials_only == SDEV_QUIESCE || | |
1089 | specials_only == SDEV_BLOCK) | |
1090 | return BLKPREP_DEFER; | |
1091 | ||
1092 | printk(KERN_ERR "scsi%d (%d:%d): rejecting I/O to device being removed\n", | |
1093 | sdev->host->host_no, sdev->id, sdev->lun); | |
1094 | return BLKPREP_KILL; | |
1095 | } | |
1096 | ||
1097 | ||
1098 | /* | |
1099 | * Now try and find a command block that we can use. | |
1100 | */ | |
1101 | if (!req->special) { | |
1102 | cmd = scsi_get_command(sdev, GFP_ATOMIC); | |
1103 | if (unlikely(!cmd)) | |
1104 | goto defer; | |
1105 | } else | |
1106 | cmd = req->special; | |
1107 | ||
1108 | /* pull a tag out of the request if we have one */ | |
1109 | cmd->tag = req->tag; | |
1110 | } else { | |
1111 | blk_dump_rq_flags(req, "SCSI bad req"); | |
1112 | return BLKPREP_KILL; | |
1113 | } | |
1114 | ||
1115 | /* note the overloading of req->special. When the tag | |
1116 | * is active it always means cmd. If the tag goes | |
1117 | * back for re-queueing, it may be reset */ | |
1118 | req->special = cmd; | |
1119 | cmd->request = req; | |
1120 | ||
1121 | /* | |
1122 | * FIXME: drop the lock here because the functions below | |
1123 | * expect to be called without the queue lock held. Also, | |
1124 | * previously, we dequeued the request before dropping the | |
1125 | * lock. We hope REQ_STARTED prevents anything untoward from | |
1126 | * happening now. | |
1127 | */ | |
1128 | if (req->flags & (REQ_CMD | REQ_BLOCK_PC)) { | |
1129 | struct scsi_driver *drv; | |
1130 | int ret; | |
1131 | ||
1132 | /* | |
1133 | * This will do a couple of things: | |
1134 | * 1) Fill in the actual SCSI command. | |
1135 | * 2) Fill in any other upper-level specific fields | |
1136 | * (timeout). | |
1137 | * | |
1138 | * If this returns 0, it means that the request failed | |
1139 | * (reading past end of disk, reading offline device, | |
1140 | * etc). This won't actually talk to the device, but | |
1141 | * some kinds of consistency checking may cause the | |
1142 | * request to be rejected immediately. | |
1143 | */ | |
1144 | ||
1145 | /* | |
1146 | * This sets up the scatter-gather table (allocating if | |
1147 | * required). | |
1148 | */ | |
1149 | ret = scsi_init_io(cmd); | |
1150 | if (ret) /* BLKPREP_KILL return also releases the command */ | |
1151 | return ret; | |
1152 | ||
1153 | /* | |
1154 | * Initialize the actual SCSI command for this request. | |
1155 | */ | |
1156 | drv = *(struct scsi_driver **)req->rq_disk->private_data; | |
1157 | if (unlikely(!drv->init_command(cmd))) { | |
1158 | scsi_release_buffers(cmd); | |
1159 | scsi_put_command(cmd); | |
1160 | return BLKPREP_KILL; | |
1161 | } | |
1162 | } | |
1163 | ||
1164 | /* | |
1165 | * The request is now prepped, no need to come back here | |
1166 | */ | |
1167 | req->flags |= REQ_DONTPREP; | |
1168 | return BLKPREP_OK; | |
1169 | ||
1170 | defer: | |
1171 | /* If we defer, the elv_next_request() returns NULL, but the | |
1172 | * queue must be restarted, so we plug here if no returning | |
1173 | * command will automatically do that. */ | |
1174 | if (sdev->device_busy == 0) | |
1175 | blk_plug_device(q); | |
1176 | return BLKPREP_DEFER; | |
1177 | } | |
1178 | ||
1179 | /* | |
1180 | * scsi_dev_queue_ready: if we can send requests to sdev, return 1 else | |
1181 | * return 0. | |
1182 | * | |
1183 | * Called with the queue_lock held. | |
1184 | */ | |
1185 | static inline int scsi_dev_queue_ready(struct request_queue *q, | |
1186 | struct scsi_device *sdev) | |
1187 | { | |
1188 | if (sdev->device_busy >= sdev->queue_depth) | |
1189 | return 0; | |
1190 | if (sdev->device_busy == 0 && sdev->device_blocked) { | |
1191 | /* | |
1192 | * unblock after device_blocked iterates to zero | |
1193 | */ | |
1194 | if (--sdev->device_blocked == 0) { | |
1195 | SCSI_LOG_MLQUEUE(3, | |
1196 | printk("scsi%d (%d:%d) unblocking device at" | |
1197 | " zero depth\n", sdev->host->host_no, | |
1198 | sdev->id, sdev->lun)); | |
1199 | } else { | |
1200 | blk_plug_device(q); | |
1201 | return 0; | |
1202 | } | |
1203 | } | |
1204 | if (sdev->device_blocked) | |
1205 | return 0; | |
1206 | ||
1207 | return 1; | |
1208 | } | |
1209 | ||
1210 | /* | |
1211 | * scsi_host_queue_ready: if we can send requests to shost, return 1 else | |
1212 | * return 0. We must end up running the queue again whenever 0 is | |
1213 | * returned, else IO can hang. | |
1214 | * | |
1215 | * Called with host_lock held. | |
1216 | */ | |
1217 | static inline int scsi_host_queue_ready(struct request_queue *q, | |
1218 | struct Scsi_Host *shost, | |
1219 | struct scsi_device *sdev) | |
1220 | { | |
1221 | if (test_bit(SHOST_RECOVERY, &shost->shost_state)) | |
1222 | return 0; | |
1223 | if (shost->host_busy == 0 && shost->host_blocked) { | |
1224 | /* | |
1225 | * unblock after host_blocked iterates to zero | |
1226 | */ | |
1227 | if (--shost->host_blocked == 0) { | |
1228 | SCSI_LOG_MLQUEUE(3, | |
1229 | printk("scsi%d unblocking host at zero depth\n", | |
1230 | shost->host_no)); | |
1231 | } else { | |
1232 | blk_plug_device(q); | |
1233 | return 0; | |
1234 | } | |
1235 | } | |
1236 | if ((shost->can_queue > 0 && shost->host_busy >= shost->can_queue) || | |
1237 | shost->host_blocked || shost->host_self_blocked) { | |
1238 | if (list_empty(&sdev->starved_entry)) | |
1239 | list_add_tail(&sdev->starved_entry, &shost->starved_list); | |
1240 | return 0; | |
1241 | } | |
1242 | ||
1243 | /* We're OK to process the command, so we can't be starved */ | |
1244 | if (!list_empty(&sdev->starved_entry)) | |
1245 | list_del_init(&sdev->starved_entry); | |
1246 | ||
1247 | return 1; | |
1248 | } | |
1249 | ||
1250 | /* | |
1251 | * Kill requests for a dead device | |
1252 | */ | |
1253 | static void scsi_kill_requests(request_queue_t *q) | |
1254 | { | |
1255 | struct request *req; | |
1256 | ||
1257 | while ((req = elv_next_request(q)) != NULL) { | |
1258 | blkdev_dequeue_request(req); | |
1259 | req->flags |= REQ_QUIET; | |
1260 | while (end_that_request_first(req, 0, req->nr_sectors)) | |
1261 | ; | |
1262 | end_that_request_last(req); | |
1263 | } | |
1264 | } | |
1265 | ||
1266 | /* | |
1267 | * Function: scsi_request_fn() | |
1268 | * | |
1269 | * Purpose: Main strategy routine for SCSI. | |
1270 | * | |
1271 | * Arguments: q - Pointer to actual queue. | |
1272 | * | |
1273 | * Returns: Nothing | |
1274 | * | |
1275 | * Lock status: IO request lock assumed to be held when called. | |
1276 | */ | |
1277 | static void scsi_request_fn(struct request_queue *q) | |
1278 | { | |
1279 | struct scsi_device *sdev = q->queuedata; | |
1280 | struct Scsi_Host *shost; | |
1281 | struct scsi_cmnd *cmd; | |
1282 | struct request *req; | |
1283 | ||
1284 | if (!sdev) { | |
1285 | printk("scsi: killing requests for dead queue\n"); | |
1286 | scsi_kill_requests(q); | |
1287 | return; | |
1288 | } | |
1289 | ||
1290 | if(!get_device(&sdev->sdev_gendev)) | |
1291 | /* We must be tearing the block queue down already */ | |
1292 | return; | |
1293 | ||
1294 | /* | |
1295 | * To start with, we keep looping until the queue is empty, or until | |
1296 | * the host is no longer able to accept any more requests. | |
1297 | */ | |
1298 | shost = sdev->host; | |
1299 | while (!blk_queue_plugged(q)) { | |
1300 | int rtn; | |
1301 | /* | |
1302 | * get next queueable request. We do this early to make sure | |
1303 | * that the request is fully prepared even if we cannot | |
1304 | * accept it. | |
1305 | */ | |
1306 | req = elv_next_request(q); | |
1307 | if (!req || !scsi_dev_queue_ready(q, sdev)) | |
1308 | break; | |
1309 | ||
1310 | if (unlikely(!scsi_device_online(sdev))) { | |
1311 | printk(KERN_ERR "scsi%d (%d:%d): rejecting I/O to offline device\n", | |
1312 | sdev->host->host_no, sdev->id, sdev->lun); | |
1313 | blkdev_dequeue_request(req); | |
1314 | req->flags |= REQ_QUIET; | |
1315 | while (end_that_request_first(req, 0, req->nr_sectors)) | |
1316 | ; | |
1317 | end_that_request_last(req); | |
1318 | continue; | |
1319 | } | |
1320 | ||
1321 | ||
1322 | /* | |
1323 | * Remove the request from the request list. | |
1324 | */ | |
1325 | if (!(blk_queue_tagged(q) && !blk_queue_start_tag(q, req))) | |
1326 | blkdev_dequeue_request(req); | |
1327 | sdev->device_busy++; | |
1328 | ||
1329 | spin_unlock(q->queue_lock); | |
1330 | spin_lock(shost->host_lock); | |
1331 | ||
1332 | if (!scsi_host_queue_ready(q, shost, sdev)) | |
1333 | goto not_ready; | |
1334 | if (sdev->single_lun) { | |
1335 | if (scsi_target(sdev)->starget_sdev_user && | |
1336 | scsi_target(sdev)->starget_sdev_user != sdev) | |
1337 | goto not_ready; | |
1338 | scsi_target(sdev)->starget_sdev_user = sdev; | |
1339 | } | |
1340 | shost->host_busy++; | |
1341 | ||
1342 | /* | |
1343 | * XXX(hch): This is rather suboptimal, scsi_dispatch_cmd will | |
1344 | * take the lock again. | |
1345 | */ | |
1346 | spin_unlock_irq(shost->host_lock); | |
1347 | ||
1348 | cmd = req->special; | |
1349 | if (unlikely(cmd == NULL)) { | |
1350 | printk(KERN_CRIT "impossible request in %s.\n" | |
1351 | "please mail a stack trace to " | |
1352 | "linux-scsi@vger.kernel.org", | |
1353 | __FUNCTION__); | |
1354 | BUG(); | |
1355 | } | |
1356 | ||
1357 | /* | |
1358 | * Finally, initialize any error handling parameters, and set up | |
1359 | * the timers for timeouts. | |
1360 | */ | |
1361 | scsi_init_cmd_errh(cmd); | |
1362 | ||
1363 | /* | |
1364 | * Dispatch the command to the low-level driver. | |
1365 | */ | |
1366 | rtn = scsi_dispatch_cmd(cmd); | |
1367 | spin_lock_irq(q->queue_lock); | |
1368 | if(rtn) { | |
1369 | /* we're refusing the command; because of | |
1370 | * the way locks get dropped, we need to | |
1371 | * check here if plugging is required */ | |
1372 | if(sdev->device_busy == 0) | |
1373 | blk_plug_device(q); | |
1374 | ||
1375 | break; | |
1376 | } | |
1377 | } | |
1378 | ||
1379 | goto out; | |
1380 | ||
1381 | not_ready: | |
1382 | spin_unlock_irq(shost->host_lock); | |
1383 | ||
1384 | /* | |
1385 | * lock q, handle tag, requeue req, and decrement device_busy. We | |
1386 | * must return with queue_lock held. | |
1387 | * | |
1388 | * Decrementing device_busy without checking it is OK, as all such | |
1389 | * cases (host limits or settings) should run the queue at some | |
1390 | * later time. | |
1391 | */ | |
1392 | spin_lock_irq(q->queue_lock); | |
1393 | blk_requeue_request(q, req); | |
1394 | sdev->device_busy--; | |
1395 | if(sdev->device_busy == 0) | |
1396 | blk_plug_device(q); | |
1397 | out: | |
1398 | /* must be careful here...if we trigger the ->remove() function | |
1399 | * we cannot be holding the q lock */ | |
1400 | spin_unlock_irq(q->queue_lock); | |
1401 | put_device(&sdev->sdev_gendev); | |
1402 | spin_lock_irq(q->queue_lock); | |
1403 | } | |
1404 | ||
1405 | u64 scsi_calculate_bounce_limit(struct Scsi_Host *shost) | |
1406 | { | |
1407 | struct device *host_dev; | |
1408 | u64 bounce_limit = 0xffffffff; | |
1409 | ||
1410 | if (shost->unchecked_isa_dma) | |
1411 | return BLK_BOUNCE_ISA; | |
1412 | /* | |
1413 | * Platforms with virtual-DMA translation | |
1414 | * hardware have no practical limit. | |
1415 | */ | |
1416 | if (!PCI_DMA_BUS_IS_PHYS) | |
1417 | return BLK_BOUNCE_ANY; | |
1418 | ||
1419 | host_dev = scsi_get_device(shost); | |
1420 | if (host_dev && host_dev->dma_mask) | |
1421 | bounce_limit = *host_dev->dma_mask; | |
1422 | ||
1423 | return bounce_limit; | |
1424 | } | |
1425 | EXPORT_SYMBOL(scsi_calculate_bounce_limit); | |
1426 | ||
1427 | struct request_queue *scsi_alloc_queue(struct scsi_device *sdev) | |
1428 | { | |
1429 | struct Scsi_Host *shost = sdev->host; | |
1430 | struct request_queue *q; | |
1431 | ||
152587de | 1432 | q = blk_init_queue(scsi_request_fn, NULL); |
1da177e4 LT |
1433 | if (!q) |
1434 | return NULL; | |
1435 | ||
1436 | blk_queue_prep_rq(q, scsi_prep_fn); | |
1437 | ||
1438 | blk_queue_max_hw_segments(q, shost->sg_tablesize); | |
1439 | blk_queue_max_phys_segments(q, SCSI_MAX_PHYS_SEGMENTS); | |
1440 | blk_queue_max_sectors(q, shost->max_sectors); | |
1441 | blk_queue_bounce_limit(q, scsi_calculate_bounce_limit(shost)); | |
1442 | blk_queue_segment_boundary(q, shost->dma_boundary); | |
1443 | blk_queue_issue_flush_fn(q, scsi_issue_flush_fn); | |
1444 | ||
1445 | /* | |
1446 | * ordered tags are superior to flush ordering | |
1447 | */ | |
1448 | if (shost->ordered_tag) | |
1449 | blk_queue_ordered(q, QUEUE_ORDERED_TAG); | |
1450 | else if (shost->ordered_flush) { | |
1451 | blk_queue_ordered(q, QUEUE_ORDERED_FLUSH); | |
1452 | q->prepare_flush_fn = scsi_prepare_flush_fn; | |
1453 | q->end_flush_fn = scsi_end_flush_fn; | |
1454 | } | |
1455 | ||
1456 | if (!shost->use_clustering) | |
1457 | clear_bit(QUEUE_FLAG_CLUSTER, &q->queue_flags); | |
1458 | return q; | |
1459 | } | |
1460 | ||
1461 | void scsi_free_queue(struct request_queue *q) | |
1462 | { | |
1463 | blk_cleanup_queue(q); | |
1464 | } | |
1465 | ||
1466 | /* | |
1467 | * Function: scsi_block_requests() | |
1468 | * | |
1469 | * Purpose: Utility function used by low-level drivers to prevent further | |
1470 | * commands from being queued to the device. | |
1471 | * | |
1472 | * Arguments: shost - Host in question | |
1473 | * | |
1474 | * Returns: Nothing | |
1475 | * | |
1476 | * Lock status: No locks are assumed held. | |
1477 | * | |
1478 | * Notes: There is no timer nor any other means by which the requests | |
1479 | * get unblocked other than the low-level driver calling | |
1480 | * scsi_unblock_requests(). | |
1481 | */ | |
1482 | void scsi_block_requests(struct Scsi_Host *shost) | |
1483 | { | |
1484 | shost->host_self_blocked = 1; | |
1485 | } | |
1486 | EXPORT_SYMBOL(scsi_block_requests); | |
1487 | ||
1488 | /* | |
1489 | * Function: scsi_unblock_requests() | |
1490 | * | |
1491 | * Purpose: Utility function used by low-level drivers to allow further | |
1492 | * commands from being queued to the device. | |
1493 | * | |
1494 | * Arguments: shost - Host in question | |
1495 | * | |
1496 | * Returns: Nothing | |
1497 | * | |
1498 | * Lock status: No locks are assumed held. | |
1499 | * | |
1500 | * Notes: There is no timer nor any other means by which the requests | |
1501 | * get unblocked other than the low-level driver calling | |
1502 | * scsi_unblock_requests(). | |
1503 | * | |
1504 | * This is done as an API function so that changes to the | |
1505 | * internals of the scsi mid-layer won't require wholesale | |
1506 | * changes to drivers that use this feature. | |
1507 | */ | |
1508 | void scsi_unblock_requests(struct Scsi_Host *shost) | |
1509 | { | |
1510 | shost->host_self_blocked = 0; | |
1511 | scsi_run_host_queues(shost); | |
1512 | } | |
1513 | EXPORT_SYMBOL(scsi_unblock_requests); | |
1514 | ||
1515 | int __init scsi_init_queue(void) | |
1516 | { | |
1517 | int i; | |
1518 | ||
1519 | for (i = 0; i < SG_MEMPOOL_NR; i++) { | |
1520 | struct scsi_host_sg_pool *sgp = scsi_sg_pools + i; | |
1521 | int size = sgp->size * sizeof(struct scatterlist); | |
1522 | ||
1523 | sgp->slab = kmem_cache_create(sgp->name, size, 0, | |
1524 | SLAB_HWCACHE_ALIGN, NULL, NULL); | |
1525 | if (!sgp->slab) { | |
1526 | printk(KERN_ERR "SCSI: can't init sg slab %s\n", | |
1527 | sgp->name); | |
1528 | } | |
1529 | ||
1530 | sgp->pool = mempool_create(SG_MEMPOOL_SIZE, | |
1531 | mempool_alloc_slab, mempool_free_slab, | |
1532 | sgp->slab); | |
1533 | if (!sgp->pool) { | |
1534 | printk(KERN_ERR "SCSI: can't init sg mempool %s\n", | |
1535 | sgp->name); | |
1536 | } | |
1537 | } | |
1538 | ||
1539 | return 0; | |
1540 | } | |
1541 | ||
1542 | void scsi_exit_queue(void) | |
1543 | { | |
1544 | int i; | |
1545 | ||
1546 | for (i = 0; i < SG_MEMPOOL_NR; i++) { | |
1547 | struct scsi_host_sg_pool *sgp = scsi_sg_pools + i; | |
1548 | mempool_destroy(sgp->pool); | |
1549 | kmem_cache_destroy(sgp->slab); | |
1550 | } | |
1551 | } | |
1552 | /** | |
1553 | * __scsi_mode_sense - issue a mode sense, falling back from 10 to | |
1554 | * six bytes if necessary. | |
1555 | * @sreq: SCSI request to fill in with the MODE_SENSE | |
1556 | * @dbd: set if mode sense will allow block descriptors to be returned | |
1557 | * @modepage: mode page being requested | |
1558 | * @buffer: request buffer (may not be smaller than eight bytes) | |
1559 | * @len: length of request buffer. | |
1560 | * @timeout: command timeout | |
1561 | * @retries: number of retries before failing | |
1562 | * @data: returns a structure abstracting the mode header data | |
1563 | * | |
1564 | * Returns zero if unsuccessful, or the header offset (either 4 | |
1565 | * or 8 depending on whether a six or ten byte command was | |
1566 | * issued) if successful. | |
1567 | **/ | |
1568 | int | |
1569 | __scsi_mode_sense(struct scsi_request *sreq, int dbd, int modepage, | |
1570 | unsigned char *buffer, int len, int timeout, int retries, | |
1571 | struct scsi_mode_data *data) { | |
1572 | unsigned char cmd[12]; | |
1573 | int use_10_for_ms; | |
1574 | int header_length; | |
1575 | ||
1576 | memset(data, 0, sizeof(*data)); | |
1577 | memset(&cmd[0], 0, 12); | |
1578 | cmd[1] = dbd & 0x18; /* allows DBD and LLBA bits */ | |
1579 | cmd[2] = modepage; | |
1580 | ||
1581 | retry: | |
1582 | use_10_for_ms = sreq->sr_device->use_10_for_ms; | |
1583 | ||
1584 | if (use_10_for_ms) { | |
1585 | if (len < 8) | |
1586 | len = 8; | |
1587 | ||
1588 | cmd[0] = MODE_SENSE_10; | |
1589 | cmd[8] = len; | |
1590 | header_length = 8; | |
1591 | } else { | |
1592 | if (len < 4) | |
1593 | len = 4; | |
1594 | ||
1595 | cmd[0] = MODE_SENSE; | |
1596 | cmd[4] = len; | |
1597 | header_length = 4; | |
1598 | } | |
1599 | ||
1600 | sreq->sr_cmd_len = 0; | |
1601 | memset(sreq->sr_sense_buffer, 0, sizeof(sreq->sr_sense_buffer)); | |
1602 | sreq->sr_data_direction = DMA_FROM_DEVICE; | |
1603 | ||
1604 | memset(buffer, 0, len); | |
1605 | ||
1606 | scsi_wait_req(sreq, cmd, buffer, len, timeout, retries); | |
1607 | ||
1608 | /* This code looks awful: what it's doing is making sure an | |
1609 | * ILLEGAL REQUEST sense return identifies the actual command | |
1610 | * byte as the problem. MODE_SENSE commands can return | |
1611 | * ILLEGAL REQUEST if the code page isn't supported */ | |
1612 | ||
1613 | if (use_10_for_ms && !scsi_status_is_good(sreq->sr_result) && | |
1614 | (driver_byte(sreq->sr_result) & DRIVER_SENSE)) { | |
1615 | struct scsi_sense_hdr sshdr; | |
1616 | ||
1617 | if (scsi_request_normalize_sense(sreq, &sshdr)) { | |
1618 | if ((sshdr.sense_key == ILLEGAL_REQUEST) && | |
1619 | (sshdr.asc == 0x20) && (sshdr.ascq == 0)) { | |
1620 | /* | |
1621 | * Invalid command operation code | |
1622 | */ | |
1623 | sreq->sr_device->use_10_for_ms = 0; | |
1624 | goto retry; | |
1625 | } | |
1626 | } | |
1627 | } | |
1628 | ||
1629 | if(scsi_status_is_good(sreq->sr_result)) { | |
1630 | data->header_length = header_length; | |
1631 | if(use_10_for_ms) { | |
1632 | data->length = buffer[0]*256 + buffer[1] + 2; | |
1633 | data->medium_type = buffer[2]; | |
1634 | data->device_specific = buffer[3]; | |
1635 | data->longlba = buffer[4] & 0x01; | |
1636 | data->block_descriptor_length = buffer[6]*256 | |
1637 | + buffer[7]; | |
1638 | } else { | |
1639 | data->length = buffer[0] + 1; | |
1640 | data->medium_type = buffer[1]; | |
1641 | data->device_specific = buffer[2]; | |
1642 | data->block_descriptor_length = buffer[3]; | |
1643 | } | |
1644 | } | |
1645 | ||
1646 | return sreq->sr_result; | |
1647 | } | |
1648 | EXPORT_SYMBOL(__scsi_mode_sense); | |
1649 | ||
1650 | /** | |
1651 | * scsi_mode_sense - issue a mode sense, falling back from 10 to | |
1652 | * six bytes if necessary. | |
1653 | * @sdev: scsi device to send command to. | |
1654 | * @dbd: set if mode sense will disable block descriptors in the return | |
1655 | * @modepage: mode page being requested | |
1656 | * @buffer: request buffer (may not be smaller than eight bytes) | |
1657 | * @len: length of request buffer. | |
1658 | * @timeout: command timeout | |
1659 | * @retries: number of retries before failing | |
1660 | * | |
1661 | * Returns zero if unsuccessful, or the header offset (either 4 | |
1662 | * or 8 depending on whether a six or ten byte command was | |
1663 | * issued) if successful. | |
1664 | **/ | |
1665 | int | |
1666 | scsi_mode_sense(struct scsi_device *sdev, int dbd, int modepage, | |
1667 | unsigned char *buffer, int len, int timeout, int retries, | |
1668 | struct scsi_mode_data *data) | |
1669 | { | |
1670 | struct scsi_request *sreq = scsi_allocate_request(sdev, GFP_KERNEL); | |
1671 | int ret; | |
1672 | ||
1673 | if (!sreq) | |
1674 | return -1; | |
1675 | ||
1676 | ret = __scsi_mode_sense(sreq, dbd, modepage, buffer, len, | |
1677 | timeout, retries, data); | |
1678 | ||
1679 | scsi_release_request(sreq); | |
1680 | ||
1681 | return ret; | |
1682 | } | |
1683 | EXPORT_SYMBOL(scsi_mode_sense); | |
1684 | ||
1685 | int | |
1686 | scsi_test_unit_ready(struct scsi_device *sdev, int timeout, int retries) | |
1687 | { | |
1688 | struct scsi_request *sreq; | |
1689 | char cmd[] = { | |
1690 | TEST_UNIT_READY, 0, 0, 0, 0, 0, | |
1691 | }; | |
1692 | int result; | |
1693 | ||
1694 | sreq = scsi_allocate_request(sdev, GFP_KERNEL); | |
1695 | if (!sreq) | |
1696 | return -ENOMEM; | |
1697 | ||
1698 | sreq->sr_data_direction = DMA_NONE; | |
1699 | scsi_wait_req(sreq, cmd, NULL, 0, timeout, retries); | |
1700 | ||
1701 | if ((driver_byte(sreq->sr_result) & DRIVER_SENSE) && sdev->removable) { | |
1702 | struct scsi_sense_hdr sshdr; | |
1703 | ||
1704 | if ((scsi_request_normalize_sense(sreq, &sshdr)) && | |
1705 | ((sshdr.sense_key == UNIT_ATTENTION) || | |
1706 | (sshdr.sense_key == NOT_READY))) { | |
1707 | sdev->changed = 1; | |
1708 | sreq->sr_result = 0; | |
1709 | } | |
1710 | } | |
1711 | result = sreq->sr_result; | |
1712 | scsi_release_request(sreq); | |
1713 | return result; | |
1714 | } | |
1715 | EXPORT_SYMBOL(scsi_test_unit_ready); | |
1716 | ||
1717 | /** | |
1718 | * scsi_device_set_state - Take the given device through the device | |
1719 | * state model. | |
1720 | * @sdev: scsi device to change the state of. | |
1721 | * @state: state to change to. | |
1722 | * | |
1723 | * Returns zero if unsuccessful or an error if the requested | |
1724 | * transition is illegal. | |
1725 | **/ | |
1726 | int | |
1727 | scsi_device_set_state(struct scsi_device *sdev, enum scsi_device_state state) | |
1728 | { | |
1729 | enum scsi_device_state oldstate = sdev->sdev_state; | |
1730 | ||
1731 | if (state == oldstate) | |
1732 | return 0; | |
1733 | ||
1734 | switch (state) { | |
1735 | case SDEV_CREATED: | |
1736 | /* There are no legal states that come back to | |
1737 | * created. This is the manually initialised start | |
1738 | * state */ | |
1739 | goto illegal; | |
1740 | ||
1741 | case SDEV_RUNNING: | |
1742 | switch (oldstate) { | |
1743 | case SDEV_CREATED: | |
1744 | case SDEV_OFFLINE: | |
1745 | case SDEV_QUIESCE: | |
1746 | case SDEV_BLOCK: | |
1747 | break; | |
1748 | default: | |
1749 | goto illegal; | |
1750 | } | |
1751 | break; | |
1752 | ||
1753 | case SDEV_QUIESCE: | |
1754 | switch (oldstate) { | |
1755 | case SDEV_RUNNING: | |
1756 | case SDEV_OFFLINE: | |
1757 | break; | |
1758 | default: | |
1759 | goto illegal; | |
1760 | } | |
1761 | break; | |
1762 | ||
1763 | case SDEV_OFFLINE: | |
1764 | switch (oldstate) { | |
1765 | case SDEV_CREATED: | |
1766 | case SDEV_RUNNING: | |
1767 | case SDEV_QUIESCE: | |
1768 | case SDEV_BLOCK: | |
1769 | break; | |
1770 | default: | |
1771 | goto illegal; | |
1772 | } | |
1773 | break; | |
1774 | ||
1775 | case SDEV_BLOCK: | |
1776 | switch (oldstate) { | |
1777 | case SDEV_CREATED: | |
1778 | case SDEV_RUNNING: | |
1779 | break; | |
1780 | default: | |
1781 | goto illegal; | |
1782 | } | |
1783 | break; | |
1784 | ||
1785 | case SDEV_CANCEL: | |
1786 | switch (oldstate) { | |
1787 | case SDEV_CREATED: | |
1788 | case SDEV_RUNNING: | |
1789 | case SDEV_OFFLINE: | |
1790 | case SDEV_BLOCK: | |
1791 | break; | |
1792 | default: | |
1793 | goto illegal; | |
1794 | } | |
1795 | break; | |
1796 | ||
1797 | case SDEV_DEL: | |
1798 | switch (oldstate) { | |
1799 | case SDEV_CANCEL: | |
1800 | break; | |
1801 | default: | |
1802 | goto illegal; | |
1803 | } | |
1804 | break; | |
1805 | ||
1806 | } | |
1807 | sdev->sdev_state = state; | |
1808 | return 0; | |
1809 | ||
1810 | illegal: | |
1811 | SCSI_LOG_ERROR_RECOVERY(1, | |
1812 | dev_printk(KERN_ERR, &sdev->sdev_gendev, | |
1813 | "Illegal state transition %s->%s\n", | |
1814 | scsi_device_state_name(oldstate), | |
1815 | scsi_device_state_name(state)) | |
1816 | ); | |
1817 | return -EINVAL; | |
1818 | } | |
1819 | EXPORT_SYMBOL(scsi_device_set_state); | |
1820 | ||
1821 | /** | |
1822 | * scsi_device_quiesce - Block user issued commands. | |
1823 | * @sdev: scsi device to quiesce. | |
1824 | * | |
1825 | * This works by trying to transition to the SDEV_QUIESCE state | |
1826 | * (which must be a legal transition). When the device is in this | |
1827 | * state, only special requests will be accepted, all others will | |
1828 | * be deferred. Since special requests may also be requeued requests, | |
1829 | * a successful return doesn't guarantee the device will be | |
1830 | * totally quiescent. | |
1831 | * | |
1832 | * Must be called with user context, may sleep. | |
1833 | * | |
1834 | * Returns zero if unsuccessful or an error if not. | |
1835 | **/ | |
1836 | int | |
1837 | scsi_device_quiesce(struct scsi_device *sdev) | |
1838 | { | |
1839 | int err = scsi_device_set_state(sdev, SDEV_QUIESCE); | |
1840 | if (err) | |
1841 | return err; | |
1842 | ||
1843 | scsi_run_queue(sdev->request_queue); | |
1844 | while (sdev->device_busy) { | |
1845 | msleep_interruptible(200); | |
1846 | scsi_run_queue(sdev->request_queue); | |
1847 | } | |
1848 | return 0; | |
1849 | } | |
1850 | EXPORT_SYMBOL(scsi_device_quiesce); | |
1851 | ||
1852 | /** | |
1853 | * scsi_device_resume - Restart user issued commands to a quiesced device. | |
1854 | * @sdev: scsi device to resume. | |
1855 | * | |
1856 | * Moves the device from quiesced back to running and restarts the | |
1857 | * queues. | |
1858 | * | |
1859 | * Must be called with user context, may sleep. | |
1860 | **/ | |
1861 | void | |
1862 | scsi_device_resume(struct scsi_device *sdev) | |
1863 | { | |
1864 | if(scsi_device_set_state(sdev, SDEV_RUNNING)) | |
1865 | return; | |
1866 | scsi_run_queue(sdev->request_queue); | |
1867 | } | |
1868 | EXPORT_SYMBOL(scsi_device_resume); | |
1869 | ||
1870 | static void | |
1871 | device_quiesce_fn(struct scsi_device *sdev, void *data) | |
1872 | { | |
1873 | scsi_device_quiesce(sdev); | |
1874 | } | |
1875 | ||
1876 | void | |
1877 | scsi_target_quiesce(struct scsi_target *starget) | |
1878 | { | |
1879 | starget_for_each_device(starget, NULL, device_quiesce_fn); | |
1880 | } | |
1881 | EXPORT_SYMBOL(scsi_target_quiesce); | |
1882 | ||
1883 | static void | |
1884 | device_resume_fn(struct scsi_device *sdev, void *data) | |
1885 | { | |
1886 | scsi_device_resume(sdev); | |
1887 | } | |
1888 | ||
1889 | void | |
1890 | scsi_target_resume(struct scsi_target *starget) | |
1891 | { | |
1892 | starget_for_each_device(starget, NULL, device_resume_fn); | |
1893 | } | |
1894 | EXPORT_SYMBOL(scsi_target_resume); | |
1895 | ||
1896 | /** | |
1897 | * scsi_internal_device_block - internal function to put a device | |
1898 | * temporarily into the SDEV_BLOCK state | |
1899 | * @sdev: device to block | |
1900 | * | |
1901 | * Block request made by scsi lld's to temporarily stop all | |
1902 | * scsi commands on the specified device. Called from interrupt | |
1903 | * or normal process context. | |
1904 | * | |
1905 | * Returns zero if successful or error if not | |
1906 | * | |
1907 | * Notes: | |
1908 | * This routine transitions the device to the SDEV_BLOCK state | |
1909 | * (which must be a legal transition). When the device is in this | |
1910 | * state, all commands are deferred until the scsi lld reenables | |
1911 | * the device with scsi_device_unblock or device_block_tmo fires. | |
1912 | * This routine assumes the host_lock is held on entry. | |
1913 | **/ | |
1914 | int | |
1915 | scsi_internal_device_block(struct scsi_device *sdev) | |
1916 | { | |
1917 | request_queue_t *q = sdev->request_queue; | |
1918 | unsigned long flags; | |
1919 | int err = 0; | |
1920 | ||
1921 | err = scsi_device_set_state(sdev, SDEV_BLOCK); | |
1922 | if (err) | |
1923 | return err; | |
1924 | ||
1925 | /* | |
1926 | * The device has transitioned to SDEV_BLOCK. Stop the | |
1927 | * block layer from calling the midlayer with this device's | |
1928 | * request queue. | |
1929 | */ | |
1930 | spin_lock_irqsave(q->queue_lock, flags); | |
1931 | blk_stop_queue(q); | |
1932 | spin_unlock_irqrestore(q->queue_lock, flags); | |
1933 | ||
1934 | return 0; | |
1935 | } | |
1936 | EXPORT_SYMBOL_GPL(scsi_internal_device_block); | |
1937 | ||
1938 | /** | |
1939 | * scsi_internal_device_unblock - resume a device after a block request | |
1940 | * @sdev: device to resume | |
1941 | * | |
1942 | * Called by scsi lld's or the midlayer to restart the device queue | |
1943 | * for the previously suspended scsi device. Called from interrupt or | |
1944 | * normal process context. | |
1945 | * | |
1946 | * Returns zero if successful or error if not. | |
1947 | * | |
1948 | * Notes: | |
1949 | * This routine transitions the device to the SDEV_RUNNING state | |
1950 | * (which must be a legal transition) allowing the midlayer to | |
1951 | * goose the queue for this device. This routine assumes the | |
1952 | * host_lock is held upon entry. | |
1953 | **/ | |
1954 | int | |
1955 | scsi_internal_device_unblock(struct scsi_device *sdev) | |
1956 | { | |
1957 | request_queue_t *q = sdev->request_queue; | |
1958 | int err; | |
1959 | unsigned long flags; | |
1960 | ||
1961 | /* | |
1962 | * Try to transition the scsi device to SDEV_RUNNING | |
1963 | * and goose the device queue if successful. | |
1964 | */ | |
1965 | err = scsi_device_set_state(sdev, SDEV_RUNNING); | |
1966 | if (err) | |
1967 | return err; | |
1968 | ||
1969 | spin_lock_irqsave(q->queue_lock, flags); | |
1970 | blk_start_queue(q); | |
1971 | spin_unlock_irqrestore(q->queue_lock, flags); | |
1972 | ||
1973 | return 0; | |
1974 | } | |
1975 | EXPORT_SYMBOL_GPL(scsi_internal_device_unblock); | |
1976 | ||
1977 | static void | |
1978 | device_block(struct scsi_device *sdev, void *data) | |
1979 | { | |
1980 | scsi_internal_device_block(sdev); | |
1981 | } | |
1982 | ||
1983 | static int | |
1984 | target_block(struct device *dev, void *data) | |
1985 | { | |
1986 | if (scsi_is_target_device(dev)) | |
1987 | starget_for_each_device(to_scsi_target(dev), NULL, | |
1988 | device_block); | |
1989 | return 0; | |
1990 | } | |
1991 | ||
1992 | void | |
1993 | scsi_target_block(struct device *dev) | |
1994 | { | |
1995 | if (scsi_is_target_device(dev)) | |
1996 | starget_for_each_device(to_scsi_target(dev), NULL, | |
1997 | device_block); | |
1998 | else | |
1999 | device_for_each_child(dev, NULL, target_block); | |
2000 | } | |
2001 | EXPORT_SYMBOL_GPL(scsi_target_block); | |
2002 | ||
2003 | static void | |
2004 | device_unblock(struct scsi_device *sdev, void *data) | |
2005 | { | |
2006 | scsi_internal_device_unblock(sdev); | |
2007 | } | |
2008 | ||
2009 | static int | |
2010 | target_unblock(struct device *dev, void *data) | |
2011 | { | |
2012 | if (scsi_is_target_device(dev)) | |
2013 | starget_for_each_device(to_scsi_target(dev), NULL, | |
2014 | device_unblock); | |
2015 | return 0; | |
2016 | } | |
2017 | ||
2018 | void | |
2019 | scsi_target_unblock(struct device *dev) | |
2020 | { | |
2021 | if (scsi_is_target_device(dev)) | |
2022 | starget_for_each_device(to_scsi_target(dev), NULL, | |
2023 | device_unblock); | |
2024 | else | |
2025 | device_for_each_child(dev, NULL, target_unblock); | |
2026 | } | |
2027 | EXPORT_SYMBOL_GPL(scsi_target_unblock); |