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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 | ||
a1bf9d1d | 66 | static void scsi_run_queue(struct request_queue *q); |
e91442b6 JB |
67 | |
68 | /* | |
69 | * Function: scsi_unprep_request() | |
70 | * | |
71 | * Purpose: Remove all preparation done for a request, including its | |
72 | * associated scsi_cmnd, so that it can be requeued. | |
73 | * | |
74 | * Arguments: req - request to unprepare | |
75 | * | |
76 | * Lock status: Assumed that no locks are held upon entry. | |
77 | * | |
78 | * Returns: Nothing. | |
79 | */ | |
80 | static void scsi_unprep_request(struct request *req) | |
81 | { | |
82 | struct scsi_cmnd *cmd = req->special; | |
83 | ||
84 | req->flags &= ~REQ_DONTPREP; | |
85 | req->special = (req->flags & REQ_SPECIAL) ? cmd->sc_request : NULL; | |
86 | ||
e91442b6 JB |
87 | scsi_put_command(cmd); |
88 | } | |
a1bf9d1d | 89 | |
1da177e4 LT |
90 | /* |
91 | * Function: scsi_queue_insert() | |
92 | * | |
93 | * Purpose: Insert a command in the midlevel queue. | |
94 | * | |
95 | * Arguments: cmd - command that we are adding to queue. | |
96 | * reason - why we are inserting command to queue. | |
97 | * | |
98 | * Lock status: Assumed that lock is not held upon entry. | |
99 | * | |
100 | * Returns: Nothing. | |
101 | * | |
102 | * Notes: We do this for one of two cases. Either the host is busy | |
103 | * and it cannot accept any more commands for the time being, | |
104 | * or the device returned QUEUE_FULL and can accept no more | |
105 | * commands. | |
106 | * Notes: This could be called either from an interrupt context or a | |
107 | * normal process context. | |
108 | */ | |
109 | int scsi_queue_insert(struct scsi_cmnd *cmd, int reason) | |
110 | { | |
111 | struct Scsi_Host *host = cmd->device->host; | |
112 | struct scsi_device *device = cmd->device; | |
a1bf9d1d TH |
113 | struct request_queue *q = device->request_queue; |
114 | unsigned long flags; | |
1da177e4 LT |
115 | |
116 | SCSI_LOG_MLQUEUE(1, | |
117 | printk("Inserting command %p into mlqueue\n", cmd)); | |
118 | ||
119 | /* | |
d8c37e7b | 120 | * Set the appropriate busy bit for the device/host. |
1da177e4 LT |
121 | * |
122 | * If the host/device isn't busy, assume that something actually | |
123 | * completed, and that we should be able to queue a command now. | |
124 | * | |
125 | * Note that the prior mid-layer assumption that any host could | |
126 | * always queue at least one command is now broken. The mid-layer | |
127 | * will implement a user specifiable stall (see | |
128 | * scsi_host.max_host_blocked and scsi_device.max_device_blocked) | |
129 | * if a command is requeued with no other commands outstanding | |
130 | * either for the device or for the host. | |
131 | */ | |
132 | if (reason == SCSI_MLQUEUE_HOST_BUSY) | |
133 | host->host_blocked = host->max_host_blocked; | |
134 | else if (reason == SCSI_MLQUEUE_DEVICE_BUSY) | |
135 | device->device_blocked = device->max_device_blocked; | |
136 | ||
1da177e4 LT |
137 | /* |
138 | * Decrement the counters, since these commands are no longer | |
139 | * active on the host/device. | |
140 | */ | |
141 | scsi_device_unbusy(device); | |
142 | ||
143 | /* | |
a1bf9d1d TH |
144 | * Requeue this command. It will go before all other commands |
145 | * that are already in the queue. | |
1da177e4 LT |
146 | * |
147 | * NOTE: there is magic here about the way the queue is plugged if | |
148 | * we have no outstanding commands. | |
149 | * | |
a1bf9d1d | 150 | * Although we *don't* plug the queue, we call the request |
1da177e4 LT |
151 | * function. The SCSI request function detects the blocked condition |
152 | * and plugs the queue appropriately. | |
a1bf9d1d TH |
153 | */ |
154 | spin_lock_irqsave(q->queue_lock, flags); | |
59897dad | 155 | blk_requeue_request(q, cmd->request); |
a1bf9d1d TH |
156 | spin_unlock_irqrestore(q->queue_lock, flags); |
157 | ||
158 | scsi_run_queue(q); | |
159 | ||
1da177e4 LT |
160 | return 0; |
161 | } | |
162 | ||
163 | /* | |
164 | * Function: scsi_do_req | |
165 | * | |
166 | * Purpose: Queue a SCSI request | |
167 | * | |
168 | * Arguments: sreq - command descriptor. | |
169 | * cmnd - actual SCSI command to be performed. | |
170 | * buffer - data buffer. | |
171 | * bufflen - size of data buffer. | |
172 | * done - completion function to be run. | |
173 | * timeout - how long to let it run before timeout. | |
174 | * retries - number of retries we allow. | |
175 | * | |
176 | * Lock status: No locks held upon entry. | |
177 | * | |
178 | * Returns: Nothing. | |
179 | * | |
180 | * Notes: This function is only used for queueing requests for things | |
181 | * like ioctls and character device requests - this is because | |
182 | * we essentially just inject a request into the queue for the | |
183 | * device. | |
184 | * | |
185 | * In order to support the scsi_device_quiesce function, we | |
186 | * now inject requests on the *head* of the device queue | |
187 | * rather than the tail. | |
188 | */ | |
189 | void scsi_do_req(struct scsi_request *sreq, const void *cmnd, | |
190 | void *buffer, unsigned bufflen, | |
191 | void (*done)(struct scsi_cmnd *), | |
192 | int timeout, int retries) | |
193 | { | |
194 | /* | |
195 | * If the upper level driver is reusing these things, then | |
196 | * we should release the low-level block now. Another one will | |
197 | * be allocated later when this request is getting queued. | |
198 | */ | |
199 | __scsi_release_request(sreq); | |
200 | ||
201 | /* | |
202 | * Our own function scsi_done (which marks the host as not busy, | |
203 | * disables the timeout counter, etc) will be called by us or by the | |
204 | * scsi_hosts[host].queuecommand() function needs to also call | |
205 | * the completion function for the high level driver. | |
206 | */ | |
207 | memcpy(sreq->sr_cmnd, cmnd, sizeof(sreq->sr_cmnd)); | |
208 | sreq->sr_bufflen = bufflen; | |
209 | sreq->sr_buffer = buffer; | |
210 | sreq->sr_allowed = retries; | |
211 | sreq->sr_done = done; | |
212 | sreq->sr_timeout_per_command = timeout; | |
213 | ||
214 | if (sreq->sr_cmd_len == 0) | |
215 | sreq->sr_cmd_len = COMMAND_SIZE(sreq->sr_cmnd[0]); | |
216 | ||
217 | /* | |
218 | * head injection *required* here otherwise quiesce won't work | |
6e68af66 MC |
219 | * |
220 | * Because users of this function are apt to reuse requests with no | |
221 | * modification, we have to sanitise the request flags here | |
1da177e4 | 222 | */ |
6e68af66 MC |
223 | sreq->sr_request->flags &= ~REQ_DONTPREP; |
224 | blk_insert_request(sreq->sr_device->request_queue, sreq->sr_request, | |
225 | 1, sreq); | |
1da177e4 LT |
226 | } |
227 | EXPORT_SYMBOL(scsi_do_req); | |
228 | ||
39216033 | 229 | /** |
33aa687d | 230 | * scsi_execute - insert request and wait for the result |
39216033 JB |
231 | * @sdev: scsi device |
232 | * @cmd: scsi command | |
233 | * @data_direction: data direction | |
234 | * @buffer: data buffer | |
235 | * @bufflen: len of buffer | |
236 | * @sense: optional sense buffer | |
237 | * @timeout: request timeout in seconds | |
238 | * @retries: number of times to retry request | |
33aa687d | 239 | * @flags: or into request flags; |
39216033 | 240 | * |
ea73a9f2 JB |
241 | * returns the req->errors value which is the the scsi_cmnd result |
242 | * field. | |
39216033 | 243 | **/ |
33aa687d JB |
244 | int scsi_execute(struct scsi_device *sdev, const unsigned char *cmd, |
245 | int data_direction, void *buffer, unsigned bufflen, | |
246 | unsigned char *sense, int timeout, int retries, int flags) | |
39216033 JB |
247 | { |
248 | struct request *req; | |
249 | int write = (data_direction == DMA_TO_DEVICE); | |
250 | int ret = DRIVER_ERROR << 24; | |
251 | ||
252 | req = blk_get_request(sdev->request_queue, write, __GFP_WAIT); | |
253 | ||
254 | if (bufflen && blk_rq_map_kern(sdev->request_queue, req, | |
255 | buffer, bufflen, __GFP_WAIT)) | |
256 | goto out; | |
257 | ||
258 | req->cmd_len = COMMAND_SIZE(cmd[0]); | |
259 | memcpy(req->cmd, cmd, req->cmd_len); | |
260 | req->sense = sense; | |
261 | req->sense_len = 0; | |
17e01f21 | 262 | req->retries = retries; |
39216033 | 263 | req->timeout = timeout; |
3173d8c3 | 264 | req->flags |= flags | REQ_BLOCK_PC | REQ_SPECIAL | REQ_QUIET; |
39216033 JB |
265 | |
266 | /* | |
267 | * head injection *required* here otherwise quiesce won't work | |
268 | */ | |
269 | blk_execute_rq(req->q, NULL, req, 1); | |
270 | ||
271 | ret = req->errors; | |
272 | out: | |
273 | blk_put_request(req); | |
274 | ||
275 | return ret; | |
276 | } | |
33aa687d | 277 | EXPORT_SYMBOL(scsi_execute); |
39216033 | 278 | |
ea73a9f2 JB |
279 | |
280 | int scsi_execute_req(struct scsi_device *sdev, const unsigned char *cmd, | |
281 | int data_direction, void *buffer, unsigned bufflen, | |
282 | struct scsi_sense_hdr *sshdr, int timeout, int retries) | |
283 | { | |
284 | char *sense = NULL; | |
1ccb48bb | 285 | int result; |
286 | ||
ea73a9f2 | 287 | if (sshdr) { |
286f3e13 | 288 | sense = kmalloc(SCSI_SENSE_BUFFERSIZE, GFP_NOIO); |
ea73a9f2 JB |
289 | if (!sense) |
290 | return DRIVER_ERROR << 24; | |
e514385b | 291 | memset(sense, 0, SCSI_SENSE_BUFFERSIZE); |
ea73a9f2 | 292 | } |
1ccb48bb | 293 | result = scsi_execute(sdev, cmd, data_direction, buffer, bufflen, |
ea73a9f2 JB |
294 | sense, timeout, retries, 0); |
295 | if (sshdr) | |
e514385b | 296 | scsi_normalize_sense(sense, SCSI_SENSE_BUFFERSIZE, sshdr); |
ea73a9f2 JB |
297 | |
298 | kfree(sense); | |
299 | return result; | |
300 | } | |
301 | EXPORT_SYMBOL(scsi_execute_req); | |
302 | ||
6e68af66 MC |
303 | struct scsi_io_context { |
304 | void *data; | |
305 | void (*done)(void *data, char *sense, int result, int resid); | |
306 | char sense[SCSI_SENSE_BUFFERSIZE]; | |
307 | }; | |
308 | ||
aa7b5cd7 MC |
309 | static kmem_cache_t *scsi_io_context_cache; |
310 | ||
6e68af66 MC |
311 | static void scsi_end_async(struct request *req) |
312 | { | |
313 | struct scsi_io_context *sioc = req->end_io_data; | |
314 | ||
315 | if (sioc->done) | |
316 | sioc->done(sioc->data, sioc->sense, req->errors, req->data_len); | |
317 | ||
aa7b5cd7 | 318 | kmem_cache_free(scsi_io_context_cache, sioc); |
6e68af66 MC |
319 | __blk_put_request(req->q, req); |
320 | } | |
321 | ||
322 | static int scsi_merge_bio(struct request *rq, struct bio *bio) | |
323 | { | |
324 | struct request_queue *q = rq->q; | |
325 | ||
326 | bio->bi_flags &= ~(1 << BIO_SEG_VALID); | |
327 | if (rq_data_dir(rq) == WRITE) | |
328 | bio->bi_rw |= (1 << BIO_RW); | |
329 | blk_queue_bounce(q, &bio); | |
330 | ||
331 | if (!rq->bio) | |
332 | blk_rq_bio_prep(q, rq, bio); | |
333 | else if (!q->back_merge_fn(q, rq, bio)) | |
334 | return -EINVAL; | |
335 | else { | |
336 | rq->biotail->bi_next = bio; | |
337 | rq->biotail = bio; | |
338 | rq->hard_nr_sectors += bio_sectors(bio); | |
339 | rq->nr_sectors = rq->hard_nr_sectors; | |
340 | } | |
341 | ||
342 | return 0; | |
343 | } | |
344 | ||
345 | static int scsi_bi_endio(struct bio *bio, unsigned int bytes_done, int error) | |
346 | { | |
347 | if (bio->bi_size) | |
348 | return 1; | |
349 | ||
350 | bio_put(bio); | |
351 | return 0; | |
352 | } | |
353 | ||
354 | /** | |
355 | * scsi_req_map_sg - map a scatterlist into a request | |
356 | * @rq: request to fill | |
357 | * @sg: scatterlist | |
358 | * @nsegs: number of elements | |
359 | * @bufflen: len of buffer | |
360 | * @gfp: memory allocation flags | |
361 | * | |
362 | * scsi_req_map_sg maps a scatterlist into a request so that the | |
363 | * request can be sent to the block layer. We do not trust the scatterlist | |
364 | * sent to use, as some ULDs use that struct to only organize the pages. | |
365 | */ | |
366 | static int scsi_req_map_sg(struct request *rq, struct scatterlist *sgl, | |
367 | int nsegs, unsigned bufflen, gfp_t gfp) | |
368 | { | |
369 | struct request_queue *q = rq->q; | |
370 | int nr_pages = (bufflen + PAGE_SIZE - 1) >> PAGE_SHIFT; | |
371 | unsigned int data_len = 0, len, bytes, off; | |
372 | struct page *page; | |
373 | struct bio *bio = NULL; | |
374 | int i, err, nr_vecs = 0; | |
375 | ||
376 | for (i = 0; i < nsegs; i++) { | |
377 | page = sgl[i].page; | |
378 | off = sgl[i].offset; | |
379 | len = sgl[i].length; | |
380 | data_len += len; | |
381 | ||
382 | while (len > 0) { | |
383 | bytes = min_t(unsigned int, len, PAGE_SIZE - off); | |
384 | ||
385 | if (!bio) { | |
386 | nr_vecs = min_t(int, BIO_MAX_PAGES, nr_pages); | |
387 | nr_pages -= nr_vecs; | |
388 | ||
389 | bio = bio_alloc(gfp, nr_vecs); | |
390 | if (!bio) { | |
391 | err = -ENOMEM; | |
392 | goto free_bios; | |
393 | } | |
394 | bio->bi_end_io = scsi_bi_endio; | |
395 | } | |
396 | ||
397 | if (bio_add_pc_page(q, bio, page, bytes, off) != | |
398 | bytes) { | |
399 | bio_put(bio); | |
400 | err = -EINVAL; | |
401 | goto free_bios; | |
402 | } | |
403 | ||
404 | if (bio->bi_vcnt >= nr_vecs) { | |
405 | err = scsi_merge_bio(rq, bio); | |
406 | if (err) { | |
407 | bio_endio(bio, bio->bi_size, 0); | |
408 | goto free_bios; | |
409 | } | |
410 | bio = NULL; | |
411 | } | |
412 | ||
413 | page++; | |
414 | len -= bytes; | |
415 | off = 0; | |
416 | } | |
417 | } | |
418 | ||
419 | rq->buffer = rq->data = NULL; | |
420 | rq->data_len = data_len; | |
421 | return 0; | |
422 | ||
423 | free_bios: | |
424 | while ((bio = rq->bio) != NULL) { | |
425 | rq->bio = bio->bi_next; | |
426 | /* | |
427 | * call endio instead of bio_put incase it was bounced | |
428 | */ | |
429 | bio_endio(bio, bio->bi_size, 0); | |
430 | } | |
431 | ||
432 | return err; | |
433 | } | |
434 | ||
435 | /** | |
436 | * scsi_execute_async - insert request | |
437 | * @sdev: scsi device | |
438 | * @cmd: scsi command | |
439 | * @data_direction: data direction | |
440 | * @buffer: data buffer (this can be a kernel buffer or scatterlist) | |
441 | * @bufflen: len of buffer | |
442 | * @use_sg: if buffer is a scatterlist this is the number of elements | |
443 | * @timeout: request timeout in seconds | |
444 | * @retries: number of times to retry request | |
445 | * @flags: or into request flags | |
446 | **/ | |
447 | int scsi_execute_async(struct scsi_device *sdev, const unsigned char *cmd, | |
448 | int data_direction, void *buffer, unsigned bufflen, | |
449 | int use_sg, int timeout, int retries, void *privdata, | |
450 | void (*done)(void *, char *, int, int), gfp_t gfp) | |
451 | { | |
452 | struct request *req; | |
453 | struct scsi_io_context *sioc; | |
454 | int err = 0; | |
455 | int write = (data_direction == DMA_TO_DEVICE); | |
456 | ||
aa7b5cd7 | 457 | sioc = kmem_cache_alloc(scsi_io_context_cache, gfp); |
6e68af66 MC |
458 | if (!sioc) |
459 | return DRIVER_ERROR << 24; | |
aa7b5cd7 | 460 | memset(sioc, 0, sizeof(*sioc)); |
6e68af66 MC |
461 | |
462 | req = blk_get_request(sdev->request_queue, write, gfp); | |
463 | if (!req) | |
464 | goto free_sense; | |
defd94b7 | 465 | req->flags |= REQ_BLOCK_PC | REQ_QUIET; |
6e68af66 MC |
466 | |
467 | if (use_sg) | |
468 | err = scsi_req_map_sg(req, buffer, use_sg, bufflen, gfp); | |
469 | else if (bufflen) | |
470 | err = blk_rq_map_kern(req->q, req, buffer, bufflen, gfp); | |
471 | ||
472 | if (err) | |
473 | goto free_req; | |
474 | ||
475 | req->cmd_len = COMMAND_SIZE(cmd[0]); | |
476 | memcpy(req->cmd, cmd, req->cmd_len); | |
477 | req->sense = sioc->sense; | |
478 | req->sense_len = 0; | |
479 | req->timeout = timeout; | |
17e01f21 | 480 | req->retries = retries; |
6e68af66 MC |
481 | req->end_io_data = sioc; |
482 | ||
483 | sioc->data = privdata; | |
484 | sioc->done = done; | |
485 | ||
486 | blk_execute_rq_nowait(req->q, NULL, req, 1, scsi_end_async); | |
487 | return 0; | |
488 | ||
489 | free_req: | |
490 | blk_put_request(req); | |
491 | free_sense: | |
492 | kfree(sioc); | |
493 | return DRIVER_ERROR << 24; | |
494 | } | |
495 | EXPORT_SYMBOL_GPL(scsi_execute_async); | |
496 | ||
1da177e4 LT |
497 | /* |
498 | * Function: scsi_init_cmd_errh() | |
499 | * | |
500 | * Purpose: Initialize cmd fields related to error handling. | |
501 | * | |
502 | * Arguments: cmd - command that is ready to be queued. | |
503 | * | |
504 | * Returns: Nothing | |
505 | * | |
506 | * Notes: This function has the job of initializing a number of | |
507 | * fields related to error handling. Typically this will | |
508 | * be called once for each command, as required. | |
509 | */ | |
510 | static int scsi_init_cmd_errh(struct scsi_cmnd *cmd) | |
511 | { | |
1da177e4 | 512 | cmd->serial_number = 0; |
1da177e4 LT |
513 | |
514 | memset(cmd->sense_buffer, 0, sizeof cmd->sense_buffer); | |
515 | ||
516 | if (cmd->cmd_len == 0) | |
517 | cmd->cmd_len = COMMAND_SIZE(cmd->cmnd[0]); | |
518 | ||
519 | /* | |
520 | * We need saved copies of a number of fields - this is because | |
521 | * error handling may need to overwrite these with different values | |
522 | * to run different commands, and once error handling is complete, | |
523 | * we will need to restore these values prior to running the actual | |
524 | * command. | |
525 | */ | |
526 | cmd->old_use_sg = cmd->use_sg; | |
527 | cmd->old_cmd_len = cmd->cmd_len; | |
528 | cmd->sc_old_data_direction = cmd->sc_data_direction; | |
529 | cmd->old_underflow = cmd->underflow; | |
530 | memcpy(cmd->data_cmnd, cmd->cmnd, sizeof(cmd->cmnd)); | |
531 | cmd->buffer = cmd->request_buffer; | |
532 | cmd->bufflen = cmd->request_bufflen; | |
1da177e4 LT |
533 | |
534 | return 1; | |
535 | } | |
536 | ||
537 | /* | |
538 | * Function: scsi_setup_cmd_retry() | |
539 | * | |
540 | * Purpose: Restore the command state for a retry | |
541 | * | |
542 | * Arguments: cmd - command to be restored | |
543 | * | |
544 | * Returns: Nothing | |
545 | * | |
546 | * Notes: Immediately prior to retrying a command, we need | |
547 | * to restore certain fields that we saved above. | |
548 | */ | |
549 | void scsi_setup_cmd_retry(struct scsi_cmnd *cmd) | |
550 | { | |
551 | memcpy(cmd->cmnd, cmd->data_cmnd, sizeof(cmd->data_cmnd)); | |
552 | cmd->request_buffer = cmd->buffer; | |
553 | cmd->request_bufflen = cmd->bufflen; | |
554 | cmd->use_sg = cmd->old_use_sg; | |
555 | cmd->cmd_len = cmd->old_cmd_len; | |
556 | cmd->sc_data_direction = cmd->sc_old_data_direction; | |
557 | cmd->underflow = cmd->old_underflow; | |
558 | } | |
559 | ||
560 | void scsi_device_unbusy(struct scsi_device *sdev) | |
561 | { | |
562 | struct Scsi_Host *shost = sdev->host; | |
563 | unsigned long flags; | |
564 | ||
565 | spin_lock_irqsave(shost->host_lock, flags); | |
566 | shost->host_busy--; | |
939647ee | 567 | if (unlikely(scsi_host_in_recovery(shost) && |
1da177e4 LT |
568 | shost->host_failed)) |
569 | scsi_eh_wakeup(shost); | |
570 | spin_unlock(shost->host_lock); | |
152587de | 571 | spin_lock(sdev->request_queue->queue_lock); |
1da177e4 | 572 | sdev->device_busy--; |
152587de | 573 | spin_unlock_irqrestore(sdev->request_queue->queue_lock, flags); |
1da177e4 LT |
574 | } |
575 | ||
576 | /* | |
577 | * Called for single_lun devices on IO completion. Clear starget_sdev_user, | |
578 | * and call blk_run_queue for all the scsi_devices on the target - | |
579 | * including current_sdev first. | |
580 | * | |
581 | * Called with *no* scsi locks held. | |
582 | */ | |
583 | static void scsi_single_lun_run(struct scsi_device *current_sdev) | |
584 | { | |
585 | struct Scsi_Host *shost = current_sdev->host; | |
586 | struct scsi_device *sdev, *tmp; | |
587 | struct scsi_target *starget = scsi_target(current_sdev); | |
588 | unsigned long flags; | |
589 | ||
590 | spin_lock_irqsave(shost->host_lock, flags); | |
591 | starget->starget_sdev_user = NULL; | |
592 | spin_unlock_irqrestore(shost->host_lock, flags); | |
593 | ||
594 | /* | |
595 | * Call blk_run_queue for all LUNs on the target, starting with | |
596 | * current_sdev. We race with others (to set starget_sdev_user), | |
597 | * but in most cases, we will be first. Ideally, each LU on the | |
598 | * target would get some limited time or requests on the target. | |
599 | */ | |
600 | blk_run_queue(current_sdev->request_queue); | |
601 | ||
602 | spin_lock_irqsave(shost->host_lock, flags); | |
603 | if (starget->starget_sdev_user) | |
604 | goto out; | |
605 | list_for_each_entry_safe(sdev, tmp, &starget->devices, | |
606 | same_target_siblings) { | |
607 | if (sdev == current_sdev) | |
608 | continue; | |
609 | if (scsi_device_get(sdev)) | |
610 | continue; | |
611 | ||
612 | spin_unlock_irqrestore(shost->host_lock, flags); | |
613 | blk_run_queue(sdev->request_queue); | |
614 | spin_lock_irqsave(shost->host_lock, flags); | |
615 | ||
616 | scsi_device_put(sdev); | |
617 | } | |
618 | out: | |
619 | spin_unlock_irqrestore(shost->host_lock, flags); | |
620 | } | |
621 | ||
622 | /* | |
623 | * Function: scsi_run_queue() | |
624 | * | |
625 | * Purpose: Select a proper request queue to serve next | |
626 | * | |
627 | * Arguments: q - last request's queue | |
628 | * | |
629 | * Returns: Nothing | |
630 | * | |
631 | * Notes: The previous command was completely finished, start | |
632 | * a new one if possible. | |
633 | */ | |
634 | static void scsi_run_queue(struct request_queue *q) | |
635 | { | |
636 | struct scsi_device *sdev = q->queuedata; | |
637 | struct Scsi_Host *shost = sdev->host; | |
638 | unsigned long flags; | |
639 | ||
640 | if (sdev->single_lun) | |
641 | scsi_single_lun_run(sdev); | |
642 | ||
643 | spin_lock_irqsave(shost->host_lock, flags); | |
644 | while (!list_empty(&shost->starved_list) && | |
645 | !shost->host_blocked && !shost->host_self_blocked && | |
646 | !((shost->can_queue > 0) && | |
647 | (shost->host_busy >= shost->can_queue))) { | |
648 | /* | |
649 | * As long as shost is accepting commands and we have | |
650 | * starved queues, call blk_run_queue. scsi_request_fn | |
651 | * drops the queue_lock and can add us back to the | |
652 | * starved_list. | |
653 | * | |
654 | * host_lock protects the starved_list and starved_entry. | |
655 | * scsi_request_fn must get the host_lock before checking | |
656 | * or modifying starved_list or starved_entry. | |
657 | */ | |
658 | sdev = list_entry(shost->starved_list.next, | |
659 | struct scsi_device, starved_entry); | |
660 | list_del_init(&sdev->starved_entry); | |
661 | spin_unlock_irqrestore(shost->host_lock, flags); | |
662 | ||
663 | blk_run_queue(sdev->request_queue); | |
664 | ||
665 | spin_lock_irqsave(shost->host_lock, flags); | |
666 | if (unlikely(!list_empty(&sdev->starved_entry))) | |
667 | /* | |
668 | * sdev lost a race, and was put back on the | |
669 | * starved list. This is unlikely but without this | |
670 | * in theory we could loop forever. | |
671 | */ | |
672 | break; | |
673 | } | |
674 | spin_unlock_irqrestore(shost->host_lock, flags); | |
675 | ||
676 | blk_run_queue(q); | |
677 | } | |
678 | ||
679 | /* | |
680 | * Function: scsi_requeue_command() | |
681 | * | |
682 | * Purpose: Handle post-processing of completed commands. | |
683 | * | |
684 | * Arguments: q - queue to operate on | |
685 | * cmd - command that may need to be requeued. | |
686 | * | |
687 | * Returns: Nothing | |
688 | * | |
689 | * Notes: After command completion, there may be blocks left | |
690 | * over which weren't finished by the previous command | |
691 | * this can be for a number of reasons - the main one is | |
692 | * I/O errors in the middle of the request, in which case | |
693 | * we need to request the blocks that come after the bad | |
694 | * sector. | |
e91442b6 | 695 | * Notes: Upon return, cmd is a stale pointer. |
1da177e4 LT |
696 | */ |
697 | static void scsi_requeue_command(struct request_queue *q, struct scsi_cmnd *cmd) | |
698 | { | |
e91442b6 | 699 | struct request *req = cmd->request; |
283369cc TH |
700 | unsigned long flags; |
701 | ||
e91442b6 | 702 | scsi_unprep_request(req); |
283369cc | 703 | spin_lock_irqsave(q->queue_lock, flags); |
e91442b6 | 704 | blk_requeue_request(q, req); |
283369cc | 705 | spin_unlock_irqrestore(q->queue_lock, flags); |
1da177e4 LT |
706 | |
707 | scsi_run_queue(q); | |
708 | } | |
709 | ||
710 | void scsi_next_command(struct scsi_cmnd *cmd) | |
711 | { | |
49d7bc64 LT |
712 | struct scsi_device *sdev = cmd->device; |
713 | struct request_queue *q = sdev->request_queue; | |
714 | ||
715 | /* need to hold a reference on the device before we let go of the cmd */ | |
716 | get_device(&sdev->sdev_gendev); | |
1da177e4 LT |
717 | |
718 | scsi_put_command(cmd); | |
719 | scsi_run_queue(q); | |
49d7bc64 LT |
720 | |
721 | /* ok to remove device now */ | |
722 | put_device(&sdev->sdev_gendev); | |
1da177e4 LT |
723 | } |
724 | ||
725 | void scsi_run_host_queues(struct Scsi_Host *shost) | |
726 | { | |
727 | struct scsi_device *sdev; | |
728 | ||
729 | shost_for_each_device(sdev, shost) | |
730 | scsi_run_queue(sdev->request_queue); | |
731 | } | |
732 | ||
733 | /* | |
734 | * Function: scsi_end_request() | |
735 | * | |
736 | * Purpose: Post-processing of completed commands (usually invoked at end | |
737 | * of upper level post-processing and scsi_io_completion). | |
738 | * | |
739 | * Arguments: cmd - command that is complete. | |
740 | * uptodate - 1 if I/O indicates success, <= 0 for I/O error. | |
741 | * bytes - number of bytes of completed I/O | |
742 | * requeue - indicates whether we should requeue leftovers. | |
743 | * | |
744 | * Lock status: Assumed that lock is not held upon entry. | |
745 | * | |
e91442b6 | 746 | * Returns: cmd if requeue required, NULL otherwise. |
1da177e4 LT |
747 | * |
748 | * Notes: This is called for block device requests in order to | |
749 | * mark some number of sectors as complete. | |
750 | * | |
751 | * We are guaranteeing that the request queue will be goosed | |
752 | * at some point during this call. | |
e91442b6 | 753 | * Notes: If cmd was requeued, upon return it will be a stale pointer. |
1da177e4 LT |
754 | */ |
755 | static struct scsi_cmnd *scsi_end_request(struct scsi_cmnd *cmd, int uptodate, | |
756 | int bytes, int requeue) | |
757 | { | |
758 | request_queue_t *q = cmd->device->request_queue; | |
759 | struct request *req = cmd->request; | |
760 | unsigned long flags; | |
761 | ||
762 | /* | |
763 | * If there are blocks left over at the end, set up the command | |
764 | * to queue the remainder of them. | |
765 | */ | |
766 | if (end_that_request_chunk(req, uptodate, bytes)) { | |
767 | int leftover = (req->hard_nr_sectors << 9); | |
768 | ||
769 | if (blk_pc_request(req)) | |
770 | leftover = req->data_len; | |
771 | ||
772 | /* kill remainder if no retrys */ | |
773 | if (!uptodate && blk_noretry_request(req)) | |
774 | end_that_request_chunk(req, 0, leftover); | |
775 | else { | |
e91442b6 | 776 | if (requeue) { |
1da177e4 LT |
777 | /* |
778 | * Bleah. Leftovers again. Stick the | |
779 | * leftovers in the front of the | |
780 | * queue, and goose the queue again. | |
781 | */ | |
782 | scsi_requeue_command(q, cmd); | |
e91442b6 JB |
783 | cmd = NULL; |
784 | } | |
1da177e4 LT |
785 | return cmd; |
786 | } | |
787 | } | |
788 | ||
789 | add_disk_randomness(req->rq_disk); | |
790 | ||
791 | spin_lock_irqsave(q->queue_lock, flags); | |
792 | if (blk_rq_tagged(req)) | |
793 | blk_queue_end_tag(q, req); | |
794 | end_that_request_last(req); | |
795 | spin_unlock_irqrestore(q->queue_lock, flags); | |
796 | ||
797 | /* | |
798 | * This will goose the queue request function at the end, so we don't | |
799 | * need to worry about launching another command. | |
800 | */ | |
801 | scsi_next_command(cmd); | |
802 | return NULL; | |
803 | } | |
804 | ||
c53033f6 | 805 | static struct scatterlist *scsi_alloc_sgtable(struct scsi_cmnd *cmd, gfp_t gfp_mask) |
1da177e4 LT |
806 | { |
807 | struct scsi_host_sg_pool *sgp; | |
808 | struct scatterlist *sgl; | |
809 | ||
810 | BUG_ON(!cmd->use_sg); | |
811 | ||
812 | switch (cmd->use_sg) { | |
813 | case 1 ... 8: | |
814 | cmd->sglist_len = 0; | |
815 | break; | |
816 | case 9 ... 16: | |
817 | cmd->sglist_len = 1; | |
818 | break; | |
819 | case 17 ... 32: | |
820 | cmd->sglist_len = 2; | |
821 | break; | |
822 | #if (SCSI_MAX_PHYS_SEGMENTS > 32) | |
823 | case 33 ... 64: | |
824 | cmd->sglist_len = 3; | |
825 | break; | |
826 | #if (SCSI_MAX_PHYS_SEGMENTS > 64) | |
827 | case 65 ... 128: | |
828 | cmd->sglist_len = 4; | |
829 | break; | |
830 | #if (SCSI_MAX_PHYS_SEGMENTS > 128) | |
831 | case 129 ... 256: | |
832 | cmd->sglist_len = 5; | |
833 | break; | |
834 | #endif | |
835 | #endif | |
836 | #endif | |
837 | default: | |
838 | return NULL; | |
839 | } | |
840 | ||
841 | sgp = scsi_sg_pools + cmd->sglist_len; | |
842 | sgl = mempool_alloc(sgp->pool, gfp_mask); | |
1da177e4 LT |
843 | return sgl; |
844 | } | |
845 | ||
846 | static void scsi_free_sgtable(struct scatterlist *sgl, int index) | |
847 | { | |
848 | struct scsi_host_sg_pool *sgp; | |
849 | ||
a77e3362 | 850 | BUG_ON(index >= SG_MEMPOOL_NR); |
1da177e4 LT |
851 | |
852 | sgp = scsi_sg_pools + index; | |
853 | mempool_free(sgl, sgp->pool); | |
854 | } | |
855 | ||
856 | /* | |
857 | * Function: scsi_release_buffers() | |
858 | * | |
859 | * Purpose: Completion processing for block device I/O requests. | |
860 | * | |
861 | * Arguments: cmd - command that we are bailing. | |
862 | * | |
863 | * Lock status: Assumed that no lock is held upon entry. | |
864 | * | |
865 | * Returns: Nothing | |
866 | * | |
867 | * Notes: In the event that an upper level driver rejects a | |
868 | * command, we must release resources allocated during | |
869 | * the __init_io() function. Primarily this would involve | |
870 | * the scatter-gather table, and potentially any bounce | |
871 | * buffers. | |
872 | */ | |
873 | static void scsi_release_buffers(struct scsi_cmnd *cmd) | |
874 | { | |
875 | struct request *req = cmd->request; | |
876 | ||
877 | /* | |
878 | * Free up any indirection buffers we allocated for DMA purposes. | |
879 | */ | |
880 | if (cmd->use_sg) | |
881 | scsi_free_sgtable(cmd->request_buffer, cmd->sglist_len); | |
882 | else if (cmd->request_buffer != req->buffer) | |
883 | kfree(cmd->request_buffer); | |
884 | ||
885 | /* | |
886 | * Zero these out. They now point to freed memory, and it is | |
887 | * dangerous to hang onto the pointers. | |
888 | */ | |
889 | cmd->buffer = NULL; | |
890 | cmd->bufflen = 0; | |
891 | cmd->request_buffer = NULL; | |
892 | cmd->request_bufflen = 0; | |
893 | } | |
894 | ||
895 | /* | |
896 | * Function: scsi_io_completion() | |
897 | * | |
898 | * Purpose: Completion processing for block device I/O requests. | |
899 | * | |
900 | * Arguments: cmd - command that is finished. | |
901 | * | |
902 | * Lock status: Assumed that no lock is held upon entry. | |
903 | * | |
904 | * Returns: Nothing | |
905 | * | |
906 | * Notes: This function is matched in terms of capabilities to | |
907 | * the function that created the scatter-gather list. | |
908 | * In other words, if there are no bounce buffers | |
909 | * (the normal case for most drivers), we don't need | |
910 | * the logic to deal with cleaning up afterwards. | |
911 | * | |
912 | * We must do one of several things here: | |
913 | * | |
914 | * a) Call scsi_end_request. This will finish off the | |
915 | * specified number of sectors. If we are done, the | |
916 | * command block will be released, and the queue | |
917 | * function will be goosed. If we are not done, then | |
918 | * scsi_end_request will directly goose the queue. | |
919 | * | |
920 | * b) We can just use scsi_requeue_command() here. This would | |
921 | * be used if we just wanted to retry, for example. | |
922 | */ | |
923 | void scsi_io_completion(struct scsi_cmnd *cmd, unsigned int good_bytes, | |
924 | unsigned int block_bytes) | |
925 | { | |
926 | int result = cmd->result; | |
927 | int this_count = cmd->bufflen; | |
928 | request_queue_t *q = cmd->device->request_queue; | |
929 | struct request *req = cmd->request; | |
930 | int clear_errors = 1; | |
931 | struct scsi_sense_hdr sshdr; | |
932 | int sense_valid = 0; | |
933 | int sense_deferred = 0; | |
934 | ||
935 | if (blk_complete_barrier_rq(q, req, good_bytes >> 9)) | |
936 | return; | |
937 | ||
938 | /* | |
939 | * Free up any indirection buffers we allocated for DMA purposes. | |
940 | * For the case of a READ, we need to copy the data out of the | |
941 | * bounce buffer and into the real buffer. | |
942 | */ | |
943 | if (cmd->use_sg) | |
944 | scsi_free_sgtable(cmd->buffer, cmd->sglist_len); | |
945 | else if (cmd->buffer != req->buffer) { | |
946 | if (rq_data_dir(req) == READ) { | |
947 | unsigned long flags; | |
948 | char *to = bio_kmap_irq(req->bio, &flags); | |
949 | memcpy(to, cmd->buffer, cmd->bufflen); | |
950 | bio_kunmap_irq(to, &flags); | |
951 | } | |
952 | kfree(cmd->buffer); | |
953 | } | |
954 | ||
955 | if (result) { | |
956 | sense_valid = scsi_command_normalize_sense(cmd, &sshdr); | |
957 | if (sense_valid) | |
958 | sense_deferred = scsi_sense_is_deferred(&sshdr); | |
959 | } | |
960 | if (blk_pc_request(req)) { /* SG_IO ioctl from block level */ | |
961 | req->errors = result; | |
962 | if (result) { | |
963 | clear_errors = 0; | |
964 | if (sense_valid && req->sense) { | |
965 | /* | |
966 | * SG_IO wants current and deferred errors | |
967 | */ | |
968 | int len = 8 + cmd->sense_buffer[7]; | |
969 | ||
970 | if (len > SCSI_SENSE_BUFFERSIZE) | |
971 | len = SCSI_SENSE_BUFFERSIZE; | |
972 | memcpy(req->sense, cmd->sense_buffer, len); | |
973 | req->sense_len = len; | |
974 | } | |
975 | } else | |
976 | req->data_len = cmd->resid; | |
977 | } | |
978 | ||
979 | /* | |
980 | * Zero these out. They now point to freed memory, and it is | |
981 | * dangerous to hang onto the pointers. | |
982 | */ | |
983 | cmd->buffer = NULL; | |
984 | cmd->bufflen = 0; | |
985 | cmd->request_buffer = NULL; | |
986 | cmd->request_bufflen = 0; | |
987 | ||
988 | /* | |
989 | * Next deal with any sectors which we were able to correctly | |
990 | * handle. | |
991 | */ | |
992 | if (good_bytes >= 0) { | |
993 | SCSI_LOG_HLCOMPLETE(1, printk("%ld sectors total, %d bytes done.\n", | |
994 | req->nr_sectors, good_bytes)); | |
995 | SCSI_LOG_HLCOMPLETE(1, printk("use_sg is %d\n", cmd->use_sg)); | |
996 | ||
997 | if (clear_errors) | |
998 | req->errors = 0; | |
999 | /* | |
1000 | * If multiple sectors are requested in one buffer, then | |
1001 | * they will have been finished off by the first command. | |
1002 | * If not, then we have a multi-buffer command. | |
1003 | * | |
1004 | * If block_bytes != 0, it means we had a medium error | |
1005 | * of some sort, and that we want to mark some number of | |
1006 | * sectors as not uptodate. Thus we want to inhibit | |
1007 | * requeueing right here - we will requeue down below | |
1008 | * when we handle the bad sectors. | |
1009 | */ | |
1da177e4 LT |
1010 | |
1011 | /* | |
e91442b6 JB |
1012 | * If the command completed without error, then either |
1013 | * finish off the rest of the command, or start a new one. | |
1da177e4 | 1014 | */ |
e91442b6 | 1015 | if (scsi_end_request(cmd, 1, good_bytes, result == 0) == NULL) |
1da177e4 | 1016 | return; |
1da177e4 LT |
1017 | } |
1018 | /* | |
1019 | * Now, if we were good little boys and girls, Santa left us a request | |
1020 | * sense buffer. We can extract information from this, so we | |
1021 | * can choose a block to remap, etc. | |
1022 | */ | |
1023 | if (sense_valid && !sense_deferred) { | |
1024 | switch (sshdr.sense_key) { | |
1025 | case UNIT_ATTENTION: | |
1026 | if (cmd->device->removable) { | |
1027 | /* detected disc change. set a bit | |
1028 | * and quietly refuse further access. | |
1029 | */ | |
1030 | cmd->device->changed = 1; | |
e91442b6 | 1031 | scsi_end_request(cmd, 0, |
1da177e4 LT |
1032 | this_count, 1); |
1033 | return; | |
1034 | } else { | |
1035 | /* | |
1036 | * Must have been a power glitch, or a | |
1037 | * bus reset. Could not have been a | |
1038 | * media change, so we just retry the | |
1039 | * request and see what happens. | |
1040 | */ | |
1041 | scsi_requeue_command(q, cmd); | |
1042 | return; | |
1043 | } | |
1044 | break; | |
1045 | case ILLEGAL_REQUEST: | |
1046 | /* | |
1047 | * If we had an ILLEGAL REQUEST returned, then we may | |
1048 | * have performed an unsupported command. The only | |
1049 | * thing this should be would be a ten byte read where | |
1050 | * only a six byte read was supported. Also, on a | |
1051 | * system where READ CAPACITY failed, we may have read | |
1052 | * past the end of the disk. | |
1053 | */ | |
26a68019 JA |
1054 | if ((cmd->device->use_10_for_rw && |
1055 | sshdr.asc == 0x20 && sshdr.ascq == 0x00) && | |
1da177e4 LT |
1056 | (cmd->cmnd[0] == READ_10 || |
1057 | cmd->cmnd[0] == WRITE_10)) { | |
1058 | cmd->device->use_10_for_rw = 0; | |
1059 | /* | |
1060 | * This will cause a retry with a 6-byte | |
1061 | * command. | |
1062 | */ | |
1063 | scsi_requeue_command(q, cmd); | |
1064 | result = 0; | |
1065 | } else { | |
e91442b6 | 1066 | scsi_end_request(cmd, 0, this_count, 1); |
1da177e4 LT |
1067 | return; |
1068 | } | |
1069 | break; | |
1070 | case NOT_READY: | |
1071 | /* | |
1072 | * If the device is in the process of becoming ready, | |
1073 | * retry. | |
1074 | */ | |
1075 | if (sshdr.asc == 0x04 && sshdr.ascq == 0x01) { | |
1076 | scsi_requeue_command(q, cmd); | |
1077 | return; | |
1078 | } | |
3173d8c3 | 1079 | if (!(req->flags & REQ_QUIET)) |
3bf743e7 JG |
1080 | scmd_printk(KERN_INFO, cmd, |
1081 | "Device not ready.\n"); | |
e91442b6 | 1082 | scsi_end_request(cmd, 0, this_count, 1); |
1da177e4 LT |
1083 | return; |
1084 | case VOLUME_OVERFLOW: | |
3173d8c3 | 1085 | if (!(req->flags & REQ_QUIET)) { |
3bf743e7 JG |
1086 | scmd_printk(KERN_INFO, cmd, |
1087 | "Volume overflow, CDB: "); | |
3173d8c3 JB |
1088 | __scsi_print_command(cmd->data_cmnd); |
1089 | scsi_print_sense("", cmd); | |
1090 | } | |
e91442b6 | 1091 | scsi_end_request(cmd, 0, block_bytes, 1); |
1da177e4 LT |
1092 | return; |
1093 | default: | |
1094 | break; | |
1095 | } | |
1096 | } /* driver byte != 0 */ | |
1097 | if (host_byte(result) == DID_RESET) { | |
1098 | /* | |
1099 | * Third party bus reset or reset for error | |
1100 | * recovery reasons. Just retry the request | |
1101 | * and see what happens. | |
1102 | */ | |
1103 | scsi_requeue_command(q, cmd); | |
1104 | return; | |
1105 | } | |
1106 | if (result) { | |
3173d8c3 | 1107 | if (!(req->flags & REQ_QUIET)) { |
3bf743e7 JG |
1108 | scmd_printk(KERN_INFO, cmd, |
1109 | "SCSI error: return code = 0x%x\n", result); | |
3173d8c3 JB |
1110 | |
1111 | if (driver_byte(result) & DRIVER_SENSE) | |
1112 | scsi_print_sense("", cmd); | |
1113 | } | |
1da177e4 LT |
1114 | /* |
1115 | * Mark a single buffer as not uptodate. Queue the remainder. | |
1116 | * We sometimes get this cruft in the event that a medium error | |
1117 | * isn't properly reported. | |
1118 | */ | |
1119 | block_bytes = req->hard_cur_sectors << 9; | |
1120 | if (!block_bytes) | |
1121 | block_bytes = req->data_len; | |
e91442b6 | 1122 | scsi_end_request(cmd, 0, block_bytes, 1); |
1da177e4 LT |
1123 | } |
1124 | } | |
1125 | EXPORT_SYMBOL(scsi_io_completion); | |
1126 | ||
1127 | /* | |
1128 | * Function: scsi_init_io() | |
1129 | * | |
1130 | * Purpose: SCSI I/O initialize function. | |
1131 | * | |
1132 | * Arguments: cmd - Command descriptor we wish to initialize | |
1133 | * | |
1134 | * Returns: 0 on success | |
1135 | * BLKPREP_DEFER if the failure is retryable | |
1136 | * BLKPREP_KILL if the failure is fatal | |
1137 | */ | |
1138 | static int scsi_init_io(struct scsi_cmnd *cmd) | |
1139 | { | |
1140 | struct request *req = cmd->request; | |
1141 | struct scatterlist *sgpnt; | |
1142 | int count; | |
1143 | ||
1144 | /* | |
1145 | * if this is a rq->data based REQ_BLOCK_PC, setup for a non-sg xfer | |
1146 | */ | |
1147 | if ((req->flags & REQ_BLOCK_PC) && !req->bio) { | |
1148 | cmd->request_bufflen = req->data_len; | |
1149 | cmd->request_buffer = req->data; | |
1150 | req->buffer = req->data; | |
1151 | cmd->use_sg = 0; | |
1152 | return 0; | |
1153 | } | |
1154 | ||
1155 | /* | |
1156 | * we used to not use scatter-gather for single segment request, | |
1157 | * but now we do (it makes highmem I/O easier to support without | |
1158 | * kmapping pages) | |
1159 | */ | |
1160 | cmd->use_sg = req->nr_phys_segments; | |
1161 | ||
1162 | /* | |
1163 | * if sg table allocation fails, requeue request later. | |
1164 | */ | |
1165 | sgpnt = scsi_alloc_sgtable(cmd, GFP_ATOMIC); | |
7c72ce81 AS |
1166 | if (unlikely(!sgpnt)) { |
1167 | scsi_unprep_request(req); | |
1da177e4 | 1168 | return BLKPREP_DEFER; |
7c72ce81 | 1169 | } |
1da177e4 LT |
1170 | |
1171 | cmd->request_buffer = (char *) sgpnt; | |
1172 | cmd->request_bufflen = req->nr_sectors << 9; | |
1173 | if (blk_pc_request(req)) | |
1174 | cmd->request_bufflen = req->data_len; | |
1175 | req->buffer = NULL; | |
1176 | ||
1177 | /* | |
1178 | * Next, walk the list, and fill in the addresses and sizes of | |
1179 | * each segment. | |
1180 | */ | |
1181 | count = blk_rq_map_sg(req->q, req, cmd->request_buffer); | |
1182 | ||
1183 | /* | |
1184 | * mapped well, send it off | |
1185 | */ | |
1186 | if (likely(count <= cmd->use_sg)) { | |
1187 | cmd->use_sg = count; | |
1188 | return 0; | |
1189 | } | |
1190 | ||
1191 | printk(KERN_ERR "Incorrect number of segments after building list\n"); | |
1192 | printk(KERN_ERR "counted %d, received %d\n", count, cmd->use_sg); | |
1193 | printk(KERN_ERR "req nr_sec %lu, cur_nr_sec %u\n", req->nr_sectors, | |
1194 | req->current_nr_sectors); | |
1195 | ||
1196 | /* release the command and kill it */ | |
1197 | scsi_release_buffers(cmd); | |
1198 | scsi_put_command(cmd); | |
1199 | return BLKPREP_KILL; | |
1200 | } | |
1201 | ||
1202 | static int scsi_prepare_flush_fn(request_queue_t *q, struct request *rq) | |
1203 | { | |
1204 | struct scsi_device *sdev = q->queuedata; | |
1205 | struct scsi_driver *drv; | |
1206 | ||
1207 | if (sdev->sdev_state == SDEV_RUNNING) { | |
1208 | drv = *(struct scsi_driver **) rq->rq_disk->private_data; | |
1209 | ||
1210 | if (drv->prepare_flush) | |
1211 | return drv->prepare_flush(q, rq); | |
1212 | } | |
1213 | ||
1214 | return 0; | |
1215 | } | |
1216 | ||
1217 | static void scsi_end_flush_fn(request_queue_t *q, struct request *rq) | |
1218 | { | |
1219 | struct scsi_device *sdev = q->queuedata; | |
1220 | struct request *flush_rq = rq->end_io_data; | |
1221 | struct scsi_driver *drv; | |
1222 | ||
1223 | if (flush_rq->errors) { | |
1224 | printk("scsi: barrier error, disabling flush support\n"); | |
1225 | blk_queue_ordered(q, QUEUE_ORDERED_NONE); | |
1226 | } | |
1227 | ||
1228 | if (sdev->sdev_state == SDEV_RUNNING) { | |
1229 | drv = *(struct scsi_driver **) rq->rq_disk->private_data; | |
1230 | drv->end_flush(q, rq); | |
1231 | } | |
1232 | } | |
1233 | ||
1234 | static int scsi_issue_flush_fn(request_queue_t *q, struct gendisk *disk, | |
1235 | sector_t *error_sector) | |
1236 | { | |
1237 | struct scsi_device *sdev = q->queuedata; | |
1238 | struct scsi_driver *drv; | |
1239 | ||
1240 | if (sdev->sdev_state != SDEV_RUNNING) | |
1241 | return -ENXIO; | |
1242 | ||
1243 | drv = *(struct scsi_driver **) disk->private_data; | |
1244 | if (drv->issue_flush) | |
1245 | return drv->issue_flush(&sdev->sdev_gendev, error_sector); | |
1246 | ||
1247 | return -EOPNOTSUPP; | |
1248 | } | |
1249 | ||
e537a36d JB |
1250 | static void scsi_generic_done(struct scsi_cmnd *cmd) |
1251 | { | |
1252 | BUG_ON(!blk_pc_request(cmd->request)); | |
0d95716d MC |
1253 | /* |
1254 | * This will complete the whole command with uptodate=1 so | |
1255 | * as far as the block layer is concerned the command completed | |
1256 | * successfully. Since this is a REQ_BLOCK_PC command the | |
1257 | * caller should check the request's errors value | |
1258 | */ | |
1259 | scsi_io_completion(cmd, cmd->bufflen, 0); | |
e537a36d JB |
1260 | } |
1261 | ||
7b16318d JB |
1262 | void scsi_setup_blk_pc_cmnd(struct scsi_cmnd *cmd) |
1263 | { | |
1264 | struct request *req = cmd->request; | |
1265 | ||
1266 | BUG_ON(sizeof(req->cmd) > sizeof(cmd->cmnd)); | |
1267 | memcpy(cmd->cmnd, req->cmd, sizeof(cmd->cmnd)); | |
1268 | cmd->cmd_len = req->cmd_len; | |
1269 | if (!req->data_len) | |
1270 | cmd->sc_data_direction = DMA_NONE; | |
1271 | else if (rq_data_dir(req) == WRITE) | |
1272 | cmd->sc_data_direction = DMA_TO_DEVICE; | |
1273 | else | |
1274 | cmd->sc_data_direction = DMA_FROM_DEVICE; | |
1275 | ||
1276 | cmd->transfersize = req->data_len; | |
1277 | cmd->allowed = req->retries; | |
1278 | cmd->timeout_per_command = req->timeout; | |
1279 | } | |
1280 | EXPORT_SYMBOL_GPL(scsi_setup_blk_pc_cmnd); | |
1281 | ||
1da177e4 LT |
1282 | static int scsi_prep_fn(struct request_queue *q, struct request *req) |
1283 | { | |
1284 | struct scsi_device *sdev = q->queuedata; | |
1285 | struct scsi_cmnd *cmd; | |
1286 | int specials_only = 0; | |
1287 | ||
1288 | /* | |
1289 | * Just check to see if the device is online. If it isn't, we | |
1290 | * refuse to process any commands. The device must be brought | |
1291 | * online before trying any recovery commands | |
1292 | */ | |
1293 | if (unlikely(!scsi_device_online(sdev))) { | |
9ccfc756 JB |
1294 | sdev_printk(KERN_ERR, sdev, |
1295 | "rejecting I/O to offline device\n"); | |
6f16b535 | 1296 | goto kill; |
1da177e4 LT |
1297 | } |
1298 | if (unlikely(sdev->sdev_state != SDEV_RUNNING)) { | |
1299 | /* OK, we're not in a running state don't prep | |
1300 | * user commands */ | |
1301 | if (sdev->sdev_state == SDEV_DEL) { | |
1302 | /* Device is fully deleted, no commands | |
1303 | * at all allowed down */ | |
9ccfc756 JB |
1304 | sdev_printk(KERN_ERR, sdev, |
1305 | "rejecting I/O to dead device\n"); | |
6f16b535 | 1306 | goto kill; |
1da177e4 LT |
1307 | } |
1308 | /* OK, we only allow special commands (i.e. not | |
1309 | * user initiated ones */ | |
1310 | specials_only = sdev->sdev_state; | |
1311 | } | |
1312 | ||
1313 | /* | |
1314 | * Find the actual device driver associated with this command. | |
1315 | * The SPECIAL requests are things like character device or | |
1316 | * ioctls, which did not originate from ll_rw_blk. Note that | |
1317 | * the special field is also used to indicate the cmd for | |
1318 | * the remainder of a partially fulfilled request that can | |
1319 | * come up when there is a medium error. We have to treat | |
1320 | * these two cases differently. We differentiate by looking | |
1321 | * at request->cmd, as this tells us the real story. | |
1322 | */ | |
e537a36d | 1323 | if (req->flags & REQ_SPECIAL && req->special) { |
1da177e4 LT |
1324 | struct scsi_request *sreq = req->special; |
1325 | ||
1326 | if (sreq->sr_magic == SCSI_REQ_MAGIC) { | |
1327 | cmd = scsi_get_command(sreq->sr_device, GFP_ATOMIC); | |
1328 | if (unlikely(!cmd)) | |
1329 | goto defer; | |
1330 | scsi_init_cmd_from_req(cmd, sreq); | |
1331 | } else | |
1332 | cmd = req->special; | |
1333 | } else if (req->flags & (REQ_CMD | REQ_BLOCK_PC)) { | |
1334 | ||
e537a36d | 1335 | if(unlikely(specials_only) && !(req->flags & REQ_SPECIAL)) { |
1da177e4 LT |
1336 | if(specials_only == SDEV_QUIESCE || |
1337 | specials_only == SDEV_BLOCK) | |
6f16b535 | 1338 | goto defer; |
1da177e4 | 1339 | |
9ccfc756 JB |
1340 | sdev_printk(KERN_ERR, sdev, |
1341 | "rejecting I/O to device being removed\n"); | |
6f16b535 | 1342 | goto kill; |
1da177e4 LT |
1343 | } |
1344 | ||
1345 | ||
1346 | /* | |
1347 | * Now try and find a command block that we can use. | |
1348 | */ | |
1349 | if (!req->special) { | |
1350 | cmd = scsi_get_command(sdev, GFP_ATOMIC); | |
1351 | if (unlikely(!cmd)) | |
1352 | goto defer; | |
1353 | } else | |
1354 | cmd = req->special; | |
1355 | ||
1356 | /* pull a tag out of the request if we have one */ | |
1357 | cmd->tag = req->tag; | |
1358 | } else { | |
1359 | blk_dump_rq_flags(req, "SCSI bad req"); | |
6f16b535 | 1360 | goto kill; |
1da177e4 LT |
1361 | } |
1362 | ||
1363 | /* note the overloading of req->special. When the tag | |
1364 | * is active it always means cmd. If the tag goes | |
1365 | * back for re-queueing, it may be reset */ | |
1366 | req->special = cmd; | |
1367 | cmd->request = req; | |
1368 | ||
1369 | /* | |
1370 | * FIXME: drop the lock here because the functions below | |
1371 | * expect to be called without the queue lock held. Also, | |
1372 | * previously, we dequeued the request before dropping the | |
1373 | * lock. We hope REQ_STARTED prevents anything untoward from | |
1374 | * happening now. | |
1375 | */ | |
1376 | if (req->flags & (REQ_CMD | REQ_BLOCK_PC)) { | |
1377 | struct scsi_driver *drv; | |
1378 | int ret; | |
1379 | ||
1380 | /* | |
1381 | * This will do a couple of things: | |
1382 | * 1) Fill in the actual SCSI command. | |
1383 | * 2) Fill in any other upper-level specific fields | |
1384 | * (timeout). | |
1385 | * | |
1386 | * If this returns 0, it means that the request failed | |
1387 | * (reading past end of disk, reading offline device, | |
1388 | * etc). This won't actually talk to the device, but | |
1389 | * some kinds of consistency checking may cause the | |
1390 | * request to be rejected immediately. | |
1391 | */ | |
1392 | ||
1393 | /* | |
1394 | * This sets up the scatter-gather table (allocating if | |
1395 | * required). | |
1396 | */ | |
1397 | ret = scsi_init_io(cmd); | |
6f16b535 | 1398 | switch(ret) { |
7c72ce81 | 1399 | /* For BLKPREP_KILL/DEFER the cmd was released */ |
6f16b535 | 1400 | case BLKPREP_KILL: |
6f16b535 MC |
1401 | goto kill; |
1402 | case BLKPREP_DEFER: | |
1403 | goto defer; | |
1404 | } | |
1da177e4 LT |
1405 | |
1406 | /* | |
1407 | * Initialize the actual SCSI command for this request. | |
1408 | */ | |
e537a36d JB |
1409 | if (req->rq_disk) { |
1410 | drv = *(struct scsi_driver **)req->rq_disk->private_data; | |
1411 | if (unlikely(!drv->init_command(cmd))) { | |
1412 | scsi_release_buffers(cmd); | |
1413 | scsi_put_command(cmd); | |
6f16b535 | 1414 | goto kill; |
e537a36d JB |
1415 | } |
1416 | } else { | |
7b16318d | 1417 | scsi_setup_blk_pc_cmnd(cmd); |
e537a36d | 1418 | cmd->done = scsi_generic_done; |
1da177e4 LT |
1419 | } |
1420 | } | |
1421 | ||
1422 | /* | |
1423 | * The request is now prepped, no need to come back here | |
1424 | */ | |
1425 | req->flags |= REQ_DONTPREP; | |
1426 | return BLKPREP_OK; | |
1427 | ||
1428 | defer: | |
1429 | /* If we defer, the elv_next_request() returns NULL, but the | |
1430 | * queue must be restarted, so we plug here if no returning | |
1431 | * command will automatically do that. */ | |
1432 | if (sdev->device_busy == 0) | |
1433 | blk_plug_device(q); | |
1434 | return BLKPREP_DEFER; | |
6f16b535 MC |
1435 | kill: |
1436 | req->errors = DID_NO_CONNECT << 16; | |
1437 | return BLKPREP_KILL; | |
1da177e4 LT |
1438 | } |
1439 | ||
1440 | /* | |
1441 | * scsi_dev_queue_ready: if we can send requests to sdev, return 1 else | |
1442 | * return 0. | |
1443 | * | |
1444 | * Called with the queue_lock held. | |
1445 | */ | |
1446 | static inline int scsi_dev_queue_ready(struct request_queue *q, | |
1447 | struct scsi_device *sdev) | |
1448 | { | |
1449 | if (sdev->device_busy >= sdev->queue_depth) | |
1450 | return 0; | |
1451 | if (sdev->device_busy == 0 && sdev->device_blocked) { | |
1452 | /* | |
1453 | * unblock after device_blocked iterates to zero | |
1454 | */ | |
1455 | if (--sdev->device_blocked == 0) { | |
1456 | SCSI_LOG_MLQUEUE(3, | |
9ccfc756 JB |
1457 | sdev_printk(KERN_INFO, sdev, |
1458 | "unblocking device at zero depth\n")); | |
1da177e4 LT |
1459 | } else { |
1460 | blk_plug_device(q); | |
1461 | return 0; | |
1462 | } | |
1463 | } | |
1464 | if (sdev->device_blocked) | |
1465 | return 0; | |
1466 | ||
1467 | return 1; | |
1468 | } | |
1469 | ||
1470 | /* | |
1471 | * scsi_host_queue_ready: if we can send requests to shost, return 1 else | |
1472 | * return 0. We must end up running the queue again whenever 0 is | |
1473 | * returned, else IO can hang. | |
1474 | * | |
1475 | * Called with host_lock held. | |
1476 | */ | |
1477 | static inline int scsi_host_queue_ready(struct request_queue *q, | |
1478 | struct Scsi_Host *shost, | |
1479 | struct scsi_device *sdev) | |
1480 | { | |
939647ee | 1481 | if (scsi_host_in_recovery(shost)) |
1da177e4 LT |
1482 | return 0; |
1483 | if (shost->host_busy == 0 && shost->host_blocked) { | |
1484 | /* | |
1485 | * unblock after host_blocked iterates to zero | |
1486 | */ | |
1487 | if (--shost->host_blocked == 0) { | |
1488 | SCSI_LOG_MLQUEUE(3, | |
1489 | printk("scsi%d unblocking host at zero depth\n", | |
1490 | shost->host_no)); | |
1491 | } else { | |
1492 | blk_plug_device(q); | |
1493 | return 0; | |
1494 | } | |
1495 | } | |
1496 | if ((shost->can_queue > 0 && shost->host_busy >= shost->can_queue) || | |
1497 | shost->host_blocked || shost->host_self_blocked) { | |
1498 | if (list_empty(&sdev->starved_entry)) | |
1499 | list_add_tail(&sdev->starved_entry, &shost->starved_list); | |
1500 | return 0; | |
1501 | } | |
1502 | ||
1503 | /* We're OK to process the command, so we can't be starved */ | |
1504 | if (!list_empty(&sdev->starved_entry)) | |
1505 | list_del_init(&sdev->starved_entry); | |
1506 | ||
1507 | return 1; | |
1508 | } | |
1509 | ||
1510 | /* | |
e91442b6 | 1511 | * Kill a request for a dead device |
1da177e4 | 1512 | */ |
e91442b6 | 1513 | static void scsi_kill_request(struct request *req, request_queue_t *q) |
1da177e4 | 1514 | { |
e91442b6 | 1515 | struct scsi_cmnd *cmd = req->special; |
1da177e4 | 1516 | |
788ce43a JB |
1517 | blkdev_dequeue_request(req); |
1518 | ||
e91442b6 JB |
1519 | if (unlikely(cmd == NULL)) { |
1520 | printk(KERN_CRIT "impossible request in %s.\n", | |
1521 | __FUNCTION__); | |
1522 | BUG(); | |
1da177e4 | 1523 | } |
e91442b6 JB |
1524 | |
1525 | scsi_init_cmd_errh(cmd); | |
1526 | cmd->result = DID_NO_CONNECT << 16; | |
1527 | atomic_inc(&cmd->device->iorequest_cnt); | |
1528 | __scsi_done(cmd); | |
1da177e4 LT |
1529 | } |
1530 | ||
1531 | /* | |
1532 | * Function: scsi_request_fn() | |
1533 | * | |
1534 | * Purpose: Main strategy routine for SCSI. | |
1535 | * | |
1536 | * Arguments: q - Pointer to actual queue. | |
1537 | * | |
1538 | * Returns: Nothing | |
1539 | * | |
1540 | * Lock status: IO request lock assumed to be held when called. | |
1541 | */ | |
1542 | static void scsi_request_fn(struct request_queue *q) | |
1543 | { | |
1544 | struct scsi_device *sdev = q->queuedata; | |
1545 | struct Scsi_Host *shost; | |
1546 | struct scsi_cmnd *cmd; | |
1547 | struct request *req; | |
1548 | ||
1549 | if (!sdev) { | |
1550 | printk("scsi: killing requests for dead queue\n"); | |
e91442b6 JB |
1551 | while ((req = elv_next_request(q)) != NULL) |
1552 | scsi_kill_request(req, q); | |
1da177e4 LT |
1553 | return; |
1554 | } | |
1555 | ||
1556 | if(!get_device(&sdev->sdev_gendev)) | |
1557 | /* We must be tearing the block queue down already */ | |
1558 | return; | |
1559 | ||
1560 | /* | |
1561 | * To start with, we keep looping until the queue is empty, or until | |
1562 | * the host is no longer able to accept any more requests. | |
1563 | */ | |
1564 | shost = sdev->host; | |
1565 | while (!blk_queue_plugged(q)) { | |
1566 | int rtn; | |
1567 | /* | |
1568 | * get next queueable request. We do this early to make sure | |
1569 | * that the request is fully prepared even if we cannot | |
1570 | * accept it. | |
1571 | */ | |
1572 | req = elv_next_request(q); | |
1573 | if (!req || !scsi_dev_queue_ready(q, sdev)) | |
1574 | break; | |
1575 | ||
1576 | if (unlikely(!scsi_device_online(sdev))) { | |
9ccfc756 JB |
1577 | sdev_printk(KERN_ERR, sdev, |
1578 | "rejecting I/O to offline device\n"); | |
e91442b6 | 1579 | scsi_kill_request(req, q); |
1da177e4 LT |
1580 | continue; |
1581 | } | |
1582 | ||
1583 | ||
1584 | /* | |
1585 | * Remove the request from the request list. | |
1586 | */ | |
1587 | if (!(blk_queue_tagged(q) && !blk_queue_start_tag(q, req))) | |
1588 | blkdev_dequeue_request(req); | |
1589 | sdev->device_busy++; | |
1590 | ||
1591 | spin_unlock(q->queue_lock); | |
e91442b6 JB |
1592 | cmd = req->special; |
1593 | if (unlikely(cmd == NULL)) { | |
1594 | printk(KERN_CRIT "impossible request in %s.\n" | |
1595 | "please mail a stack trace to " | |
1596 | "linux-scsi@vger.kernel.org", | |
1597 | __FUNCTION__); | |
1598 | BUG(); | |
1599 | } | |
1da177e4 LT |
1600 | spin_lock(shost->host_lock); |
1601 | ||
1602 | if (!scsi_host_queue_ready(q, shost, sdev)) | |
1603 | goto not_ready; | |
1604 | if (sdev->single_lun) { | |
1605 | if (scsi_target(sdev)->starget_sdev_user && | |
1606 | scsi_target(sdev)->starget_sdev_user != sdev) | |
1607 | goto not_ready; | |
1608 | scsi_target(sdev)->starget_sdev_user = sdev; | |
1609 | } | |
1610 | shost->host_busy++; | |
1611 | ||
1612 | /* | |
1613 | * XXX(hch): This is rather suboptimal, scsi_dispatch_cmd will | |
1614 | * take the lock again. | |
1615 | */ | |
1616 | spin_unlock_irq(shost->host_lock); | |
1617 | ||
1da177e4 LT |
1618 | /* |
1619 | * Finally, initialize any error handling parameters, and set up | |
1620 | * the timers for timeouts. | |
1621 | */ | |
1622 | scsi_init_cmd_errh(cmd); | |
1623 | ||
1624 | /* | |
1625 | * Dispatch the command to the low-level driver. | |
1626 | */ | |
1627 | rtn = scsi_dispatch_cmd(cmd); | |
1628 | spin_lock_irq(q->queue_lock); | |
1629 | if(rtn) { | |
1630 | /* we're refusing the command; because of | |
1631 | * the way locks get dropped, we need to | |
1632 | * check here if plugging is required */ | |
1633 | if(sdev->device_busy == 0) | |
1634 | blk_plug_device(q); | |
1635 | ||
1636 | break; | |
1637 | } | |
1638 | } | |
1639 | ||
1640 | goto out; | |
1641 | ||
1642 | not_ready: | |
1643 | spin_unlock_irq(shost->host_lock); | |
1644 | ||
1645 | /* | |
1646 | * lock q, handle tag, requeue req, and decrement device_busy. We | |
1647 | * must return with queue_lock held. | |
1648 | * | |
1649 | * Decrementing device_busy without checking it is OK, as all such | |
1650 | * cases (host limits or settings) should run the queue at some | |
1651 | * later time. | |
1652 | */ | |
1653 | spin_lock_irq(q->queue_lock); | |
1654 | blk_requeue_request(q, req); | |
1655 | sdev->device_busy--; | |
1656 | if(sdev->device_busy == 0) | |
1657 | blk_plug_device(q); | |
1658 | out: | |
1659 | /* must be careful here...if we trigger the ->remove() function | |
1660 | * we cannot be holding the q lock */ | |
1661 | spin_unlock_irq(q->queue_lock); | |
1662 | put_device(&sdev->sdev_gendev); | |
1663 | spin_lock_irq(q->queue_lock); | |
1664 | } | |
1665 | ||
1666 | u64 scsi_calculate_bounce_limit(struct Scsi_Host *shost) | |
1667 | { | |
1668 | struct device *host_dev; | |
1669 | u64 bounce_limit = 0xffffffff; | |
1670 | ||
1671 | if (shost->unchecked_isa_dma) | |
1672 | return BLK_BOUNCE_ISA; | |
1673 | /* | |
1674 | * Platforms with virtual-DMA translation | |
1675 | * hardware have no practical limit. | |
1676 | */ | |
1677 | if (!PCI_DMA_BUS_IS_PHYS) | |
1678 | return BLK_BOUNCE_ANY; | |
1679 | ||
1680 | host_dev = scsi_get_device(shost); | |
1681 | if (host_dev && host_dev->dma_mask) | |
1682 | bounce_limit = *host_dev->dma_mask; | |
1683 | ||
1684 | return bounce_limit; | |
1685 | } | |
1686 | EXPORT_SYMBOL(scsi_calculate_bounce_limit); | |
1687 | ||
1688 | struct request_queue *scsi_alloc_queue(struct scsi_device *sdev) | |
1689 | { | |
1690 | struct Scsi_Host *shost = sdev->host; | |
1691 | struct request_queue *q; | |
1692 | ||
152587de | 1693 | q = blk_init_queue(scsi_request_fn, NULL); |
1da177e4 LT |
1694 | if (!q) |
1695 | return NULL; | |
1696 | ||
1697 | blk_queue_prep_rq(q, scsi_prep_fn); | |
1698 | ||
1699 | blk_queue_max_hw_segments(q, shost->sg_tablesize); | |
1700 | blk_queue_max_phys_segments(q, SCSI_MAX_PHYS_SEGMENTS); | |
1701 | blk_queue_max_sectors(q, shost->max_sectors); | |
1702 | blk_queue_bounce_limit(q, scsi_calculate_bounce_limit(shost)); | |
1703 | blk_queue_segment_boundary(q, shost->dma_boundary); | |
1704 | blk_queue_issue_flush_fn(q, scsi_issue_flush_fn); | |
1705 | ||
1706 | /* | |
1707 | * ordered tags are superior to flush ordering | |
1708 | */ | |
1709 | if (shost->ordered_tag) | |
1710 | blk_queue_ordered(q, QUEUE_ORDERED_TAG); | |
1711 | else if (shost->ordered_flush) { | |
1712 | blk_queue_ordered(q, QUEUE_ORDERED_FLUSH); | |
1713 | q->prepare_flush_fn = scsi_prepare_flush_fn; | |
1714 | q->end_flush_fn = scsi_end_flush_fn; | |
1715 | } | |
1716 | ||
1717 | if (!shost->use_clustering) | |
1718 | clear_bit(QUEUE_FLAG_CLUSTER, &q->queue_flags); | |
1719 | return q; | |
1720 | } | |
1721 | ||
1722 | void scsi_free_queue(struct request_queue *q) | |
1723 | { | |
1724 | blk_cleanup_queue(q); | |
1725 | } | |
1726 | ||
1727 | /* | |
1728 | * Function: scsi_block_requests() | |
1729 | * | |
1730 | * Purpose: Utility function used by low-level drivers to prevent further | |
1731 | * commands from being queued to the device. | |
1732 | * | |
1733 | * Arguments: shost - Host in question | |
1734 | * | |
1735 | * Returns: Nothing | |
1736 | * | |
1737 | * Lock status: No locks are assumed held. | |
1738 | * | |
1739 | * Notes: There is no timer nor any other means by which the requests | |
1740 | * get unblocked other than the low-level driver calling | |
1741 | * scsi_unblock_requests(). | |
1742 | */ | |
1743 | void scsi_block_requests(struct Scsi_Host *shost) | |
1744 | { | |
1745 | shost->host_self_blocked = 1; | |
1746 | } | |
1747 | EXPORT_SYMBOL(scsi_block_requests); | |
1748 | ||
1749 | /* | |
1750 | * Function: scsi_unblock_requests() | |
1751 | * | |
1752 | * Purpose: Utility function used by low-level drivers to allow further | |
1753 | * commands from being queued to the device. | |
1754 | * | |
1755 | * Arguments: shost - Host in question | |
1756 | * | |
1757 | * Returns: Nothing | |
1758 | * | |
1759 | * Lock status: No locks are assumed held. | |
1760 | * | |
1761 | * Notes: There is no timer nor any other means by which the requests | |
1762 | * get unblocked other than the low-level driver calling | |
1763 | * scsi_unblock_requests(). | |
1764 | * | |
1765 | * This is done as an API function so that changes to the | |
1766 | * internals of the scsi mid-layer won't require wholesale | |
1767 | * changes to drivers that use this feature. | |
1768 | */ | |
1769 | void scsi_unblock_requests(struct Scsi_Host *shost) | |
1770 | { | |
1771 | shost->host_self_blocked = 0; | |
1772 | scsi_run_host_queues(shost); | |
1773 | } | |
1774 | EXPORT_SYMBOL(scsi_unblock_requests); | |
1775 | ||
1776 | int __init scsi_init_queue(void) | |
1777 | { | |
1778 | int i; | |
1779 | ||
aa7b5cd7 MC |
1780 | scsi_io_context_cache = kmem_cache_create("scsi_io_context", |
1781 | sizeof(struct scsi_io_context), | |
1782 | 0, 0, NULL, NULL); | |
1783 | if (!scsi_io_context_cache) { | |
1784 | printk(KERN_ERR "SCSI: can't init scsi io context cache\n"); | |
1785 | return -ENOMEM; | |
1786 | } | |
1787 | ||
1da177e4 LT |
1788 | for (i = 0; i < SG_MEMPOOL_NR; i++) { |
1789 | struct scsi_host_sg_pool *sgp = scsi_sg_pools + i; | |
1790 | int size = sgp->size * sizeof(struct scatterlist); | |
1791 | ||
1792 | sgp->slab = kmem_cache_create(sgp->name, size, 0, | |
1793 | SLAB_HWCACHE_ALIGN, NULL, NULL); | |
1794 | if (!sgp->slab) { | |
1795 | printk(KERN_ERR "SCSI: can't init sg slab %s\n", | |
1796 | sgp->name); | |
1797 | } | |
1798 | ||
1799 | sgp->pool = mempool_create(SG_MEMPOOL_SIZE, | |
1800 | mempool_alloc_slab, mempool_free_slab, | |
1801 | sgp->slab); | |
1802 | if (!sgp->pool) { | |
1803 | printk(KERN_ERR "SCSI: can't init sg mempool %s\n", | |
1804 | sgp->name); | |
1805 | } | |
1806 | } | |
1807 | ||
1808 | return 0; | |
1809 | } | |
1810 | ||
1811 | void scsi_exit_queue(void) | |
1812 | { | |
1813 | int i; | |
1814 | ||
aa7b5cd7 MC |
1815 | kmem_cache_destroy(scsi_io_context_cache); |
1816 | ||
1da177e4 LT |
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 | /** | |
ea73a9f2 | 1824 | * scsi_mode_sense - issue a mode sense, falling back from 10 to |
1da177e4 | 1825 | * six bytes if necessary. |
1cf72699 | 1826 | * @sdev: SCSI device to be queried |
1da177e4 LT |
1827 | * @dbd: set if mode sense will allow block descriptors to be returned |
1828 | * @modepage: mode page being requested | |
1829 | * @buffer: request buffer (may not be smaller than eight bytes) | |
1830 | * @len: length of request buffer. | |
1831 | * @timeout: command timeout | |
1832 | * @retries: number of retries before failing | |
1833 | * @data: returns a structure abstracting the mode header data | |
1cf72699 JB |
1834 | * @sense: place to put sense data (or NULL if no sense to be collected). |
1835 | * must be SCSI_SENSE_BUFFERSIZE big. | |
1da177e4 LT |
1836 | * |
1837 | * Returns zero if unsuccessful, or the header offset (either 4 | |
1838 | * or 8 depending on whether a six or ten byte command was | |
1839 | * issued) if successful. | |
1840 | **/ | |
1841 | int | |
1cf72699 | 1842 | scsi_mode_sense(struct scsi_device *sdev, int dbd, int modepage, |
1da177e4 | 1843 | unsigned char *buffer, int len, int timeout, int retries, |
ea73a9f2 | 1844 | struct scsi_mode_data *data, struct scsi_sense_hdr *sshdr) { |
1da177e4 LT |
1845 | unsigned char cmd[12]; |
1846 | int use_10_for_ms; | |
1847 | int header_length; | |
1cf72699 | 1848 | int result; |
ea73a9f2 | 1849 | struct scsi_sense_hdr my_sshdr; |
1da177e4 LT |
1850 | |
1851 | memset(data, 0, sizeof(*data)); | |
1852 | memset(&cmd[0], 0, 12); | |
1853 | cmd[1] = dbd & 0x18; /* allows DBD and LLBA bits */ | |
1854 | cmd[2] = modepage; | |
1855 | ||
ea73a9f2 JB |
1856 | /* caller might not be interested in sense, but we need it */ |
1857 | if (!sshdr) | |
1858 | sshdr = &my_sshdr; | |
1859 | ||
1da177e4 | 1860 | retry: |
1cf72699 | 1861 | use_10_for_ms = sdev->use_10_for_ms; |
1da177e4 LT |
1862 | |
1863 | if (use_10_for_ms) { | |
1864 | if (len < 8) | |
1865 | len = 8; | |
1866 | ||
1867 | cmd[0] = MODE_SENSE_10; | |
1868 | cmd[8] = len; | |
1869 | header_length = 8; | |
1870 | } else { | |
1871 | if (len < 4) | |
1872 | len = 4; | |
1873 | ||
1874 | cmd[0] = MODE_SENSE; | |
1875 | cmd[4] = len; | |
1876 | header_length = 4; | |
1877 | } | |
1878 | ||
1da177e4 LT |
1879 | memset(buffer, 0, len); |
1880 | ||
1cf72699 | 1881 | result = scsi_execute_req(sdev, cmd, DMA_FROM_DEVICE, buffer, len, |
ea73a9f2 | 1882 | sshdr, timeout, retries); |
1da177e4 LT |
1883 | |
1884 | /* This code looks awful: what it's doing is making sure an | |
1885 | * ILLEGAL REQUEST sense return identifies the actual command | |
1886 | * byte as the problem. MODE_SENSE commands can return | |
1887 | * ILLEGAL REQUEST if the code page isn't supported */ | |
1888 | ||
1cf72699 JB |
1889 | if (use_10_for_ms && !scsi_status_is_good(result) && |
1890 | (driver_byte(result) & DRIVER_SENSE)) { | |
ea73a9f2 JB |
1891 | if (scsi_sense_valid(sshdr)) { |
1892 | if ((sshdr->sense_key == ILLEGAL_REQUEST) && | |
1893 | (sshdr->asc == 0x20) && (sshdr->ascq == 0)) { | |
1da177e4 LT |
1894 | /* |
1895 | * Invalid command operation code | |
1896 | */ | |
1cf72699 | 1897 | sdev->use_10_for_ms = 0; |
1da177e4 LT |
1898 | goto retry; |
1899 | } | |
1900 | } | |
1901 | } | |
1902 | ||
1cf72699 | 1903 | if(scsi_status_is_good(result)) { |
1da177e4 LT |
1904 | data->header_length = header_length; |
1905 | if(use_10_for_ms) { | |
1906 | data->length = buffer[0]*256 + buffer[1] + 2; | |
1907 | data->medium_type = buffer[2]; | |
1908 | data->device_specific = buffer[3]; | |
1909 | data->longlba = buffer[4] & 0x01; | |
1910 | data->block_descriptor_length = buffer[6]*256 | |
1911 | + buffer[7]; | |
1912 | } else { | |
1913 | data->length = buffer[0] + 1; | |
1914 | data->medium_type = buffer[1]; | |
1915 | data->device_specific = buffer[2]; | |
1916 | data->block_descriptor_length = buffer[3]; | |
1917 | } | |
1918 | } | |
1919 | ||
1cf72699 | 1920 | return result; |
1da177e4 LT |
1921 | } |
1922 | EXPORT_SYMBOL(scsi_mode_sense); | |
1923 | ||
1924 | int | |
1925 | scsi_test_unit_ready(struct scsi_device *sdev, int timeout, int retries) | |
1926 | { | |
1da177e4 LT |
1927 | char cmd[] = { |
1928 | TEST_UNIT_READY, 0, 0, 0, 0, 0, | |
1929 | }; | |
ea73a9f2 | 1930 | struct scsi_sense_hdr sshdr; |
1da177e4 LT |
1931 | int result; |
1932 | ||
ea73a9f2 | 1933 | result = scsi_execute_req(sdev, cmd, DMA_NONE, NULL, 0, &sshdr, |
1cf72699 | 1934 | timeout, retries); |
1da177e4 | 1935 | |
1cf72699 | 1936 | if ((driver_byte(result) & DRIVER_SENSE) && sdev->removable) { |
1da177e4 | 1937 | |
ea73a9f2 | 1938 | if ((scsi_sense_valid(&sshdr)) && |
1da177e4 LT |
1939 | ((sshdr.sense_key == UNIT_ATTENTION) || |
1940 | (sshdr.sense_key == NOT_READY))) { | |
1941 | sdev->changed = 1; | |
1cf72699 | 1942 | result = 0; |
1da177e4 LT |
1943 | } |
1944 | } | |
1da177e4 LT |
1945 | return result; |
1946 | } | |
1947 | EXPORT_SYMBOL(scsi_test_unit_ready); | |
1948 | ||
1949 | /** | |
1950 | * scsi_device_set_state - Take the given device through the device | |
1951 | * state model. | |
1952 | * @sdev: scsi device to change the state of. | |
1953 | * @state: state to change to. | |
1954 | * | |
1955 | * Returns zero if unsuccessful or an error if the requested | |
1956 | * transition is illegal. | |
1957 | **/ | |
1958 | int | |
1959 | scsi_device_set_state(struct scsi_device *sdev, enum scsi_device_state state) | |
1960 | { | |
1961 | enum scsi_device_state oldstate = sdev->sdev_state; | |
1962 | ||
1963 | if (state == oldstate) | |
1964 | return 0; | |
1965 | ||
1966 | switch (state) { | |
1967 | case SDEV_CREATED: | |
1968 | /* There are no legal states that come back to | |
1969 | * created. This is the manually initialised start | |
1970 | * state */ | |
1971 | goto illegal; | |
1972 | ||
1973 | case SDEV_RUNNING: | |
1974 | switch (oldstate) { | |
1975 | case SDEV_CREATED: | |
1976 | case SDEV_OFFLINE: | |
1977 | case SDEV_QUIESCE: | |
1978 | case SDEV_BLOCK: | |
1979 | break; | |
1980 | default: | |
1981 | goto illegal; | |
1982 | } | |
1983 | break; | |
1984 | ||
1985 | case SDEV_QUIESCE: | |
1986 | switch (oldstate) { | |
1987 | case SDEV_RUNNING: | |
1988 | case SDEV_OFFLINE: | |
1989 | break; | |
1990 | default: | |
1991 | goto illegal; | |
1992 | } | |
1993 | break; | |
1994 | ||
1995 | case SDEV_OFFLINE: | |
1996 | switch (oldstate) { | |
1997 | case SDEV_CREATED: | |
1998 | case SDEV_RUNNING: | |
1999 | case SDEV_QUIESCE: | |
2000 | case SDEV_BLOCK: | |
2001 | break; | |
2002 | default: | |
2003 | goto illegal; | |
2004 | } | |
2005 | break; | |
2006 | ||
2007 | case SDEV_BLOCK: | |
2008 | switch (oldstate) { | |
2009 | case SDEV_CREATED: | |
2010 | case SDEV_RUNNING: | |
2011 | break; | |
2012 | default: | |
2013 | goto illegal; | |
2014 | } | |
2015 | break; | |
2016 | ||
2017 | case SDEV_CANCEL: | |
2018 | switch (oldstate) { | |
2019 | case SDEV_CREATED: | |
2020 | case SDEV_RUNNING: | |
2021 | case SDEV_OFFLINE: | |
2022 | case SDEV_BLOCK: | |
2023 | break; | |
2024 | default: | |
2025 | goto illegal; | |
2026 | } | |
2027 | break; | |
2028 | ||
2029 | case SDEV_DEL: | |
2030 | switch (oldstate) { | |
2031 | case SDEV_CANCEL: | |
2032 | break; | |
2033 | default: | |
2034 | goto illegal; | |
2035 | } | |
2036 | break; | |
2037 | ||
2038 | } | |
2039 | sdev->sdev_state = state; | |
2040 | return 0; | |
2041 | ||
2042 | illegal: | |
2043 | SCSI_LOG_ERROR_RECOVERY(1, | |
9ccfc756 JB |
2044 | sdev_printk(KERN_ERR, sdev, |
2045 | "Illegal state transition %s->%s\n", | |
2046 | scsi_device_state_name(oldstate), | |
2047 | scsi_device_state_name(state)) | |
1da177e4 LT |
2048 | ); |
2049 | return -EINVAL; | |
2050 | } | |
2051 | EXPORT_SYMBOL(scsi_device_set_state); | |
2052 | ||
2053 | /** | |
2054 | * scsi_device_quiesce - Block user issued commands. | |
2055 | * @sdev: scsi device to quiesce. | |
2056 | * | |
2057 | * This works by trying to transition to the SDEV_QUIESCE state | |
2058 | * (which must be a legal transition). When the device is in this | |
2059 | * state, only special requests will be accepted, all others will | |
2060 | * be deferred. Since special requests may also be requeued requests, | |
2061 | * a successful return doesn't guarantee the device will be | |
2062 | * totally quiescent. | |
2063 | * | |
2064 | * Must be called with user context, may sleep. | |
2065 | * | |
2066 | * Returns zero if unsuccessful or an error if not. | |
2067 | **/ | |
2068 | int | |
2069 | scsi_device_quiesce(struct scsi_device *sdev) | |
2070 | { | |
2071 | int err = scsi_device_set_state(sdev, SDEV_QUIESCE); | |
2072 | if (err) | |
2073 | return err; | |
2074 | ||
2075 | scsi_run_queue(sdev->request_queue); | |
2076 | while (sdev->device_busy) { | |
2077 | msleep_interruptible(200); | |
2078 | scsi_run_queue(sdev->request_queue); | |
2079 | } | |
2080 | return 0; | |
2081 | } | |
2082 | EXPORT_SYMBOL(scsi_device_quiesce); | |
2083 | ||
2084 | /** | |
2085 | * scsi_device_resume - Restart user issued commands to a quiesced device. | |
2086 | * @sdev: scsi device to resume. | |
2087 | * | |
2088 | * Moves the device from quiesced back to running and restarts the | |
2089 | * queues. | |
2090 | * | |
2091 | * Must be called with user context, may sleep. | |
2092 | **/ | |
2093 | void | |
2094 | scsi_device_resume(struct scsi_device *sdev) | |
2095 | { | |
2096 | if(scsi_device_set_state(sdev, SDEV_RUNNING)) | |
2097 | return; | |
2098 | scsi_run_queue(sdev->request_queue); | |
2099 | } | |
2100 | EXPORT_SYMBOL(scsi_device_resume); | |
2101 | ||
2102 | static void | |
2103 | device_quiesce_fn(struct scsi_device *sdev, void *data) | |
2104 | { | |
2105 | scsi_device_quiesce(sdev); | |
2106 | } | |
2107 | ||
2108 | void | |
2109 | scsi_target_quiesce(struct scsi_target *starget) | |
2110 | { | |
2111 | starget_for_each_device(starget, NULL, device_quiesce_fn); | |
2112 | } | |
2113 | EXPORT_SYMBOL(scsi_target_quiesce); | |
2114 | ||
2115 | static void | |
2116 | device_resume_fn(struct scsi_device *sdev, void *data) | |
2117 | { | |
2118 | scsi_device_resume(sdev); | |
2119 | } | |
2120 | ||
2121 | void | |
2122 | scsi_target_resume(struct scsi_target *starget) | |
2123 | { | |
2124 | starget_for_each_device(starget, NULL, device_resume_fn); | |
2125 | } | |
2126 | EXPORT_SYMBOL(scsi_target_resume); | |
2127 | ||
2128 | /** | |
2129 | * scsi_internal_device_block - internal function to put a device | |
2130 | * temporarily into the SDEV_BLOCK state | |
2131 | * @sdev: device to block | |
2132 | * | |
2133 | * Block request made by scsi lld's to temporarily stop all | |
2134 | * scsi commands on the specified device. Called from interrupt | |
2135 | * or normal process context. | |
2136 | * | |
2137 | * Returns zero if successful or error if not | |
2138 | * | |
2139 | * Notes: | |
2140 | * This routine transitions the device to the SDEV_BLOCK state | |
2141 | * (which must be a legal transition). When the device is in this | |
2142 | * state, all commands are deferred until the scsi lld reenables | |
2143 | * the device with scsi_device_unblock or device_block_tmo fires. | |
2144 | * This routine assumes the host_lock is held on entry. | |
2145 | **/ | |
2146 | int | |
2147 | scsi_internal_device_block(struct scsi_device *sdev) | |
2148 | { | |
2149 | request_queue_t *q = sdev->request_queue; | |
2150 | unsigned long flags; | |
2151 | int err = 0; | |
2152 | ||
2153 | err = scsi_device_set_state(sdev, SDEV_BLOCK); | |
2154 | if (err) | |
2155 | return err; | |
2156 | ||
2157 | /* | |
2158 | * The device has transitioned to SDEV_BLOCK. Stop the | |
2159 | * block layer from calling the midlayer with this device's | |
2160 | * request queue. | |
2161 | */ | |
2162 | spin_lock_irqsave(q->queue_lock, flags); | |
2163 | blk_stop_queue(q); | |
2164 | spin_unlock_irqrestore(q->queue_lock, flags); | |
2165 | ||
2166 | return 0; | |
2167 | } | |
2168 | EXPORT_SYMBOL_GPL(scsi_internal_device_block); | |
2169 | ||
2170 | /** | |
2171 | * scsi_internal_device_unblock - resume a device after a block request | |
2172 | * @sdev: device to resume | |
2173 | * | |
2174 | * Called by scsi lld's or the midlayer to restart the device queue | |
2175 | * for the previously suspended scsi device. Called from interrupt or | |
2176 | * normal process context. | |
2177 | * | |
2178 | * Returns zero if successful or error if not. | |
2179 | * | |
2180 | * Notes: | |
2181 | * This routine transitions the device to the SDEV_RUNNING state | |
2182 | * (which must be a legal transition) allowing the midlayer to | |
2183 | * goose the queue for this device. This routine assumes the | |
2184 | * host_lock is held upon entry. | |
2185 | **/ | |
2186 | int | |
2187 | scsi_internal_device_unblock(struct scsi_device *sdev) | |
2188 | { | |
2189 | request_queue_t *q = sdev->request_queue; | |
2190 | int err; | |
2191 | unsigned long flags; | |
2192 | ||
2193 | /* | |
2194 | * Try to transition the scsi device to SDEV_RUNNING | |
2195 | * and goose the device queue if successful. | |
2196 | */ | |
2197 | err = scsi_device_set_state(sdev, SDEV_RUNNING); | |
2198 | if (err) | |
2199 | return err; | |
2200 | ||
2201 | spin_lock_irqsave(q->queue_lock, flags); | |
2202 | blk_start_queue(q); | |
2203 | spin_unlock_irqrestore(q->queue_lock, flags); | |
2204 | ||
2205 | return 0; | |
2206 | } | |
2207 | EXPORT_SYMBOL_GPL(scsi_internal_device_unblock); | |
2208 | ||
2209 | static void | |
2210 | device_block(struct scsi_device *sdev, void *data) | |
2211 | { | |
2212 | scsi_internal_device_block(sdev); | |
2213 | } | |
2214 | ||
2215 | static int | |
2216 | target_block(struct device *dev, void *data) | |
2217 | { | |
2218 | if (scsi_is_target_device(dev)) | |
2219 | starget_for_each_device(to_scsi_target(dev), NULL, | |
2220 | device_block); | |
2221 | return 0; | |
2222 | } | |
2223 | ||
2224 | void | |
2225 | scsi_target_block(struct device *dev) | |
2226 | { | |
2227 | if (scsi_is_target_device(dev)) | |
2228 | starget_for_each_device(to_scsi_target(dev), NULL, | |
2229 | device_block); | |
2230 | else | |
2231 | device_for_each_child(dev, NULL, target_block); | |
2232 | } | |
2233 | EXPORT_SYMBOL_GPL(scsi_target_block); | |
2234 | ||
2235 | static void | |
2236 | device_unblock(struct scsi_device *sdev, void *data) | |
2237 | { | |
2238 | scsi_internal_device_unblock(sdev); | |
2239 | } | |
2240 | ||
2241 | static int | |
2242 | target_unblock(struct device *dev, void *data) | |
2243 | { | |
2244 | if (scsi_is_target_device(dev)) | |
2245 | starget_for_each_device(to_scsi_target(dev), NULL, | |
2246 | device_unblock); | |
2247 | return 0; | |
2248 | } | |
2249 | ||
2250 | void | |
2251 | scsi_target_unblock(struct device *dev) | |
2252 | { | |
2253 | if (scsi_is_target_device(dev)) | |
2254 | starget_for_each_device(to_scsi_target(dev), NULL, | |
2255 | device_unblock); | |
2256 | else | |
2257 | device_for_each_child(dev, NULL, target_unblock); | |
2258 | } | |
2259 | EXPORT_SYMBOL_GPL(scsi_target_unblock); |