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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> | |
faead26d | 19 | #include <linux/hardirq.h> |
1da177e4 LT |
20 | |
21 | #include <scsi/scsi.h> | |
22 | #include <scsi/scsi_dbg.h> | |
23 | #include <scsi/scsi_device.h> | |
24 | #include <scsi/scsi_driver.h> | |
25 | #include <scsi/scsi_eh.h> | |
26 | #include <scsi/scsi_host.h> | |
27 | #include <scsi/scsi_request.h> | |
28 | ||
29 | #include "scsi_priv.h" | |
30 | #include "scsi_logging.h" | |
31 | ||
32 | ||
33 | #define SG_MEMPOOL_NR (sizeof(scsi_sg_pools)/sizeof(struct scsi_host_sg_pool)) | |
34 | #define SG_MEMPOOL_SIZE 32 | |
35 | ||
36 | struct scsi_host_sg_pool { | |
37 | size_t size; | |
38 | char *name; | |
39 | kmem_cache_t *slab; | |
40 | mempool_t *pool; | |
41 | }; | |
42 | ||
43 | #if (SCSI_MAX_PHYS_SEGMENTS < 32) | |
44 | #error SCSI_MAX_PHYS_SEGMENTS is too small | |
45 | #endif | |
46 | ||
47 | #define SP(x) { x, "sgpool-" #x } | |
52c1da39 | 48 | static struct scsi_host_sg_pool scsi_sg_pools[] = { |
1da177e4 LT |
49 | SP(8), |
50 | SP(16), | |
51 | SP(32), | |
52 | #if (SCSI_MAX_PHYS_SEGMENTS > 32) | |
53 | SP(64), | |
54 | #if (SCSI_MAX_PHYS_SEGMENTS > 64) | |
55 | SP(128), | |
56 | #if (SCSI_MAX_PHYS_SEGMENTS > 128) | |
57 | SP(256), | |
58 | #if (SCSI_MAX_PHYS_SEGMENTS > 256) | |
59 | #error SCSI_MAX_PHYS_SEGMENTS is too large | |
60 | #endif | |
61 | #endif | |
62 | #endif | |
63 | #endif | |
64 | }; | |
65 | #undef SP | |
66 | ||
a1bf9d1d | 67 | static void scsi_run_queue(struct request_queue *q); |
e91442b6 JB |
68 | |
69 | /* | |
70 | * Function: scsi_unprep_request() | |
71 | * | |
72 | * Purpose: Remove all preparation done for a request, including its | |
73 | * associated scsi_cmnd, so that it can be requeued. | |
74 | * | |
75 | * Arguments: req - request to unprepare | |
76 | * | |
77 | * Lock status: Assumed that no locks are held upon entry. | |
78 | * | |
79 | * Returns: Nothing. | |
80 | */ | |
81 | static void scsi_unprep_request(struct request *req) | |
82 | { | |
83 | struct scsi_cmnd *cmd = req->special; | |
84 | ||
85 | req->flags &= ~REQ_DONTPREP; | |
86 | req->special = (req->flags & REQ_SPECIAL) ? cmd->sc_request : NULL; | |
87 | ||
e91442b6 JB |
88 | scsi_put_command(cmd); |
89 | } | |
a1bf9d1d | 90 | |
1da177e4 LT |
91 | /* |
92 | * Function: scsi_queue_insert() | |
93 | * | |
94 | * Purpose: Insert a command in the midlevel queue. | |
95 | * | |
96 | * Arguments: cmd - command that we are adding to queue. | |
97 | * reason - why we are inserting command to queue. | |
98 | * | |
99 | * Lock status: Assumed that lock is not held upon entry. | |
100 | * | |
101 | * Returns: Nothing. | |
102 | * | |
103 | * Notes: We do this for one of two cases. Either the host is busy | |
104 | * and it cannot accept any more commands for the time being, | |
105 | * or the device returned QUEUE_FULL and can accept no more | |
106 | * commands. | |
107 | * Notes: This could be called either from an interrupt context or a | |
108 | * normal process context. | |
109 | */ | |
110 | int scsi_queue_insert(struct scsi_cmnd *cmd, int reason) | |
111 | { | |
112 | struct Scsi_Host *host = cmd->device->host; | |
113 | struct scsi_device *device = cmd->device; | |
a1bf9d1d TH |
114 | struct request_queue *q = device->request_queue; |
115 | unsigned long flags; | |
1da177e4 LT |
116 | |
117 | SCSI_LOG_MLQUEUE(1, | |
118 | printk("Inserting command %p into mlqueue\n", cmd)); | |
119 | ||
120 | /* | |
d8c37e7b | 121 | * Set the appropriate busy bit for the device/host. |
1da177e4 LT |
122 | * |
123 | * If the host/device isn't busy, assume that something actually | |
124 | * completed, and that we should be able to queue a command now. | |
125 | * | |
126 | * Note that the prior mid-layer assumption that any host could | |
127 | * always queue at least one command is now broken. The mid-layer | |
128 | * will implement a user specifiable stall (see | |
129 | * scsi_host.max_host_blocked and scsi_device.max_device_blocked) | |
130 | * if a command is requeued with no other commands outstanding | |
131 | * either for the device or for the host. | |
132 | */ | |
133 | if (reason == SCSI_MLQUEUE_HOST_BUSY) | |
134 | host->host_blocked = host->max_host_blocked; | |
135 | else if (reason == SCSI_MLQUEUE_DEVICE_BUSY) | |
136 | device->device_blocked = device->max_device_blocked; | |
137 | ||
1da177e4 LT |
138 | /* |
139 | * Decrement the counters, since these commands are no longer | |
140 | * active on the host/device. | |
141 | */ | |
142 | scsi_device_unbusy(device); | |
143 | ||
144 | /* | |
a1bf9d1d TH |
145 | * Requeue this command. It will go before all other commands |
146 | * that are already in the queue. | |
1da177e4 LT |
147 | * |
148 | * NOTE: there is magic here about the way the queue is plugged if | |
149 | * we have no outstanding commands. | |
150 | * | |
a1bf9d1d | 151 | * Although we *don't* plug the queue, we call the request |
1da177e4 LT |
152 | * function. The SCSI request function detects the blocked condition |
153 | * and plugs the queue appropriately. | |
a1bf9d1d TH |
154 | */ |
155 | spin_lock_irqsave(q->queue_lock, flags); | |
59897dad | 156 | blk_requeue_request(q, cmd->request); |
a1bf9d1d TH |
157 | spin_unlock_irqrestore(q->queue_lock, flags); |
158 | ||
159 | scsi_run_queue(q); | |
160 | ||
1da177e4 LT |
161 | return 0; |
162 | } | |
163 | ||
164 | /* | |
165 | * Function: scsi_do_req | |
166 | * | |
167 | * Purpose: Queue a SCSI request | |
168 | * | |
169 | * Arguments: sreq - command descriptor. | |
170 | * cmnd - actual SCSI command to be performed. | |
171 | * buffer - data buffer. | |
172 | * bufflen - size of data buffer. | |
173 | * done - completion function to be run. | |
174 | * timeout - how long to let it run before timeout. | |
175 | * retries - number of retries we allow. | |
176 | * | |
177 | * Lock status: No locks held upon entry. | |
178 | * | |
179 | * Returns: Nothing. | |
180 | * | |
181 | * Notes: This function is only used for queueing requests for things | |
182 | * like ioctls and character device requests - this is because | |
183 | * we essentially just inject a request into the queue for the | |
184 | * device. | |
185 | * | |
186 | * In order to support the scsi_device_quiesce function, we | |
187 | * now inject requests on the *head* of the device queue | |
188 | * rather than the tail. | |
189 | */ | |
190 | void scsi_do_req(struct scsi_request *sreq, const void *cmnd, | |
191 | void *buffer, unsigned bufflen, | |
192 | void (*done)(struct scsi_cmnd *), | |
193 | int timeout, int retries) | |
194 | { | |
195 | /* | |
196 | * If the upper level driver is reusing these things, then | |
197 | * we should release the low-level block now. Another one will | |
198 | * be allocated later when this request is getting queued. | |
199 | */ | |
200 | __scsi_release_request(sreq); | |
201 | ||
202 | /* | |
203 | * Our own function scsi_done (which marks the host as not busy, | |
204 | * disables the timeout counter, etc) will be called by us or by the | |
205 | * scsi_hosts[host].queuecommand() function needs to also call | |
206 | * the completion function for the high level driver. | |
207 | */ | |
208 | memcpy(sreq->sr_cmnd, cmnd, sizeof(sreq->sr_cmnd)); | |
209 | sreq->sr_bufflen = bufflen; | |
210 | sreq->sr_buffer = buffer; | |
211 | sreq->sr_allowed = retries; | |
212 | sreq->sr_done = done; | |
213 | sreq->sr_timeout_per_command = timeout; | |
214 | ||
215 | if (sreq->sr_cmd_len == 0) | |
216 | sreq->sr_cmd_len = COMMAND_SIZE(sreq->sr_cmnd[0]); | |
217 | ||
218 | /* | |
219 | * head injection *required* here otherwise quiesce won't work | |
6e68af66 MC |
220 | * |
221 | * Because users of this function are apt to reuse requests with no | |
222 | * modification, we have to sanitise the request flags here | |
1da177e4 | 223 | */ |
6e68af66 MC |
224 | sreq->sr_request->flags &= ~REQ_DONTPREP; |
225 | blk_insert_request(sreq->sr_device->request_queue, sreq->sr_request, | |
226 | 1, sreq); | |
1da177e4 LT |
227 | } |
228 | EXPORT_SYMBOL(scsi_do_req); | |
229 | ||
39216033 | 230 | /** |
33aa687d | 231 | * scsi_execute - insert request and wait for the result |
39216033 JB |
232 | * @sdev: scsi device |
233 | * @cmd: scsi command | |
234 | * @data_direction: data direction | |
235 | * @buffer: data buffer | |
236 | * @bufflen: len of buffer | |
237 | * @sense: optional sense buffer | |
238 | * @timeout: request timeout in seconds | |
239 | * @retries: number of times to retry request | |
33aa687d | 240 | * @flags: or into request flags; |
39216033 | 241 | * |
ea73a9f2 JB |
242 | * returns the req->errors value which is the the scsi_cmnd result |
243 | * field. | |
39216033 | 244 | **/ |
33aa687d JB |
245 | int scsi_execute(struct scsi_device *sdev, const unsigned char *cmd, |
246 | int data_direction, void *buffer, unsigned bufflen, | |
247 | unsigned char *sense, int timeout, int retries, int flags) | |
39216033 JB |
248 | { |
249 | struct request *req; | |
250 | int write = (data_direction == DMA_TO_DEVICE); | |
251 | int ret = DRIVER_ERROR << 24; | |
252 | ||
253 | req = blk_get_request(sdev->request_queue, write, __GFP_WAIT); | |
254 | ||
255 | if (bufflen && blk_rq_map_kern(sdev->request_queue, req, | |
256 | buffer, bufflen, __GFP_WAIT)) | |
257 | goto out; | |
258 | ||
259 | req->cmd_len = COMMAND_SIZE(cmd[0]); | |
260 | memcpy(req->cmd, cmd, req->cmd_len); | |
261 | req->sense = sense; | |
262 | req->sense_len = 0; | |
17e01f21 | 263 | req->retries = retries; |
39216033 | 264 | req->timeout = timeout; |
3173d8c3 | 265 | req->flags |= flags | REQ_BLOCK_PC | REQ_SPECIAL | REQ_QUIET; |
39216033 JB |
266 | |
267 | /* | |
268 | * head injection *required* here otherwise quiesce won't work | |
269 | */ | |
270 | blk_execute_rq(req->q, NULL, req, 1); | |
271 | ||
272 | ret = req->errors; | |
273 | out: | |
274 | blk_put_request(req); | |
275 | ||
276 | return ret; | |
277 | } | |
33aa687d | 278 | EXPORT_SYMBOL(scsi_execute); |
39216033 | 279 | |
ea73a9f2 JB |
280 | |
281 | int scsi_execute_req(struct scsi_device *sdev, const unsigned char *cmd, | |
282 | int data_direction, void *buffer, unsigned bufflen, | |
283 | struct scsi_sense_hdr *sshdr, int timeout, int retries) | |
284 | { | |
285 | char *sense = NULL; | |
1ccb48bb | 286 | int result; |
287 | ||
ea73a9f2 | 288 | if (sshdr) { |
24669f75 | 289 | sense = kzalloc(SCSI_SENSE_BUFFERSIZE, GFP_NOIO); |
ea73a9f2 JB |
290 | if (!sense) |
291 | return DRIVER_ERROR << 24; | |
ea73a9f2 | 292 | } |
1ccb48bb | 293 | result = scsi_execute(sdev, cmd, data_direction, buffer, bufflen, |
24669f75 | 294 | sense, timeout, retries, 0); |
ea73a9f2 | 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 | ||
e650c305 | 311 | static void scsi_end_async(struct request *req, int uptodate) |
6e68af66 MC |
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 | |
bb1d1073 | 439 | * @cmd_len: length of scsi cdb |
6e68af66 MC |
440 | * @data_direction: data direction |
441 | * @buffer: data buffer (this can be a kernel buffer or scatterlist) | |
442 | * @bufflen: len of buffer | |
443 | * @use_sg: if buffer is a scatterlist this is the number of elements | |
444 | * @timeout: request timeout in seconds | |
445 | * @retries: number of times to retry request | |
446 | * @flags: or into request flags | |
447 | **/ | |
448 | int scsi_execute_async(struct scsi_device *sdev, const unsigned char *cmd, | |
bb1d1073 | 449 | int cmd_len, int data_direction, void *buffer, unsigned bufflen, |
6e68af66 MC |
450 | int use_sg, int timeout, int retries, void *privdata, |
451 | void (*done)(void *, char *, int, int), gfp_t gfp) | |
452 | { | |
453 | struct request *req; | |
454 | struct scsi_io_context *sioc; | |
455 | int err = 0; | |
456 | int write = (data_direction == DMA_TO_DEVICE); | |
457 | ||
aa7b5cd7 | 458 | sioc = kmem_cache_alloc(scsi_io_context_cache, gfp); |
6e68af66 MC |
459 | if (!sioc) |
460 | return DRIVER_ERROR << 24; | |
aa7b5cd7 | 461 | memset(sioc, 0, sizeof(*sioc)); |
6e68af66 MC |
462 | |
463 | req = blk_get_request(sdev->request_queue, write, gfp); | |
464 | if (!req) | |
465 | goto free_sense; | |
defd94b7 | 466 | req->flags |= REQ_BLOCK_PC | REQ_QUIET; |
6e68af66 MC |
467 | |
468 | if (use_sg) | |
469 | err = scsi_req_map_sg(req, buffer, use_sg, bufflen, gfp); | |
470 | else if (bufflen) | |
471 | err = blk_rq_map_kern(req->q, req, buffer, bufflen, gfp); | |
472 | ||
473 | if (err) | |
474 | goto free_req; | |
475 | ||
bb1d1073 | 476 | req->cmd_len = cmd_len; |
6e68af66 MC |
477 | memcpy(req->cmd, cmd, req->cmd_len); |
478 | req->sense = sioc->sense; | |
479 | req->sense_len = 0; | |
480 | req->timeout = timeout; | |
17e01f21 | 481 | req->retries = retries; |
6e68af66 MC |
482 | req->end_io_data = sioc; |
483 | ||
484 | sioc->data = privdata; | |
485 | sioc->done = done; | |
486 | ||
487 | blk_execute_rq_nowait(req->q, NULL, req, 1, scsi_end_async); | |
488 | return 0; | |
489 | ||
490 | free_req: | |
491 | blk_put_request(req); | |
492 | free_sense: | |
493 | kfree(sioc); | |
494 | return DRIVER_ERROR << 24; | |
495 | } | |
496 | EXPORT_SYMBOL_GPL(scsi_execute_async); | |
497 | ||
1da177e4 LT |
498 | /* |
499 | * Function: scsi_init_cmd_errh() | |
500 | * | |
501 | * Purpose: Initialize cmd fields related to error handling. | |
502 | * | |
503 | * Arguments: cmd - command that is ready to be queued. | |
504 | * | |
505 | * Returns: Nothing | |
506 | * | |
507 | * Notes: This function has the job of initializing a number of | |
508 | * fields related to error handling. Typically this will | |
509 | * be called once for each command, as required. | |
510 | */ | |
511 | static int scsi_init_cmd_errh(struct scsi_cmnd *cmd) | |
512 | { | |
1da177e4 | 513 | cmd->serial_number = 0; |
1da177e4 LT |
514 | |
515 | memset(cmd->sense_buffer, 0, sizeof cmd->sense_buffer); | |
516 | ||
517 | if (cmd->cmd_len == 0) | |
518 | cmd->cmd_len = COMMAND_SIZE(cmd->cmnd[0]); | |
519 | ||
520 | /* | |
521 | * We need saved copies of a number of fields - this is because | |
522 | * error handling may need to overwrite these with different values | |
523 | * to run different commands, and once error handling is complete, | |
524 | * we will need to restore these values prior to running the actual | |
525 | * command. | |
526 | */ | |
527 | cmd->old_use_sg = cmd->use_sg; | |
528 | cmd->old_cmd_len = cmd->cmd_len; | |
529 | cmd->sc_old_data_direction = cmd->sc_data_direction; | |
530 | cmd->old_underflow = cmd->underflow; | |
531 | memcpy(cmd->data_cmnd, cmd->cmnd, sizeof(cmd->cmnd)); | |
532 | cmd->buffer = cmd->request_buffer; | |
533 | cmd->bufflen = cmd->request_bufflen; | |
1da177e4 LT |
534 | |
535 | return 1; | |
536 | } | |
537 | ||
538 | /* | |
539 | * Function: scsi_setup_cmd_retry() | |
540 | * | |
541 | * Purpose: Restore the command state for a retry | |
542 | * | |
543 | * Arguments: cmd - command to be restored | |
544 | * | |
545 | * Returns: Nothing | |
546 | * | |
547 | * Notes: Immediately prior to retrying a command, we need | |
548 | * to restore certain fields that we saved above. | |
549 | */ | |
550 | void scsi_setup_cmd_retry(struct scsi_cmnd *cmd) | |
551 | { | |
552 | memcpy(cmd->cmnd, cmd->data_cmnd, sizeof(cmd->data_cmnd)); | |
553 | cmd->request_buffer = cmd->buffer; | |
554 | cmd->request_bufflen = cmd->bufflen; | |
555 | cmd->use_sg = cmd->old_use_sg; | |
556 | cmd->cmd_len = cmd->old_cmd_len; | |
557 | cmd->sc_data_direction = cmd->sc_old_data_direction; | |
558 | cmd->underflow = cmd->old_underflow; | |
559 | } | |
560 | ||
561 | void scsi_device_unbusy(struct scsi_device *sdev) | |
562 | { | |
563 | struct Scsi_Host *shost = sdev->host; | |
564 | unsigned long flags; | |
565 | ||
566 | spin_lock_irqsave(shost->host_lock, flags); | |
567 | shost->host_busy--; | |
939647ee | 568 | if (unlikely(scsi_host_in_recovery(shost) && |
1da177e4 LT |
569 | shost->host_failed)) |
570 | scsi_eh_wakeup(shost); | |
571 | spin_unlock(shost->host_lock); | |
152587de | 572 | spin_lock(sdev->request_queue->queue_lock); |
1da177e4 | 573 | sdev->device_busy--; |
152587de | 574 | spin_unlock_irqrestore(sdev->request_queue->queue_lock, flags); |
1da177e4 LT |
575 | } |
576 | ||
577 | /* | |
578 | * Called for single_lun devices on IO completion. Clear starget_sdev_user, | |
579 | * and call blk_run_queue for all the scsi_devices on the target - | |
580 | * including current_sdev first. | |
581 | * | |
582 | * Called with *no* scsi locks held. | |
583 | */ | |
584 | static void scsi_single_lun_run(struct scsi_device *current_sdev) | |
585 | { | |
586 | struct Scsi_Host *shost = current_sdev->host; | |
587 | struct scsi_device *sdev, *tmp; | |
588 | struct scsi_target *starget = scsi_target(current_sdev); | |
589 | unsigned long flags; | |
590 | ||
591 | spin_lock_irqsave(shost->host_lock, flags); | |
592 | starget->starget_sdev_user = NULL; | |
593 | spin_unlock_irqrestore(shost->host_lock, flags); | |
594 | ||
595 | /* | |
596 | * Call blk_run_queue for all LUNs on the target, starting with | |
597 | * current_sdev. We race with others (to set starget_sdev_user), | |
598 | * but in most cases, we will be first. Ideally, each LU on the | |
599 | * target would get some limited time or requests on the target. | |
600 | */ | |
601 | blk_run_queue(current_sdev->request_queue); | |
602 | ||
603 | spin_lock_irqsave(shost->host_lock, flags); | |
604 | if (starget->starget_sdev_user) | |
605 | goto out; | |
606 | list_for_each_entry_safe(sdev, tmp, &starget->devices, | |
607 | same_target_siblings) { | |
608 | if (sdev == current_sdev) | |
609 | continue; | |
610 | if (scsi_device_get(sdev)) | |
611 | continue; | |
612 | ||
613 | spin_unlock_irqrestore(shost->host_lock, flags); | |
614 | blk_run_queue(sdev->request_queue); | |
615 | spin_lock_irqsave(shost->host_lock, flags); | |
616 | ||
617 | scsi_device_put(sdev); | |
618 | } | |
619 | out: | |
620 | spin_unlock_irqrestore(shost->host_lock, flags); | |
621 | } | |
622 | ||
623 | /* | |
624 | * Function: scsi_run_queue() | |
625 | * | |
626 | * Purpose: Select a proper request queue to serve next | |
627 | * | |
628 | * Arguments: q - last request's queue | |
629 | * | |
630 | * Returns: Nothing | |
631 | * | |
632 | * Notes: The previous command was completely finished, start | |
633 | * a new one if possible. | |
634 | */ | |
635 | static void scsi_run_queue(struct request_queue *q) | |
636 | { | |
637 | struct scsi_device *sdev = q->queuedata; | |
638 | struct Scsi_Host *shost = sdev->host; | |
639 | unsigned long flags; | |
640 | ||
641 | if (sdev->single_lun) | |
642 | scsi_single_lun_run(sdev); | |
643 | ||
644 | spin_lock_irqsave(shost->host_lock, flags); | |
645 | while (!list_empty(&shost->starved_list) && | |
646 | !shost->host_blocked && !shost->host_self_blocked && | |
647 | !((shost->can_queue > 0) && | |
648 | (shost->host_busy >= shost->can_queue))) { | |
649 | /* | |
650 | * As long as shost is accepting commands and we have | |
651 | * starved queues, call blk_run_queue. scsi_request_fn | |
652 | * drops the queue_lock and can add us back to the | |
653 | * starved_list. | |
654 | * | |
655 | * host_lock protects the starved_list and starved_entry. | |
656 | * scsi_request_fn must get the host_lock before checking | |
657 | * or modifying starved_list or starved_entry. | |
658 | */ | |
659 | sdev = list_entry(shost->starved_list.next, | |
660 | struct scsi_device, starved_entry); | |
661 | list_del_init(&sdev->starved_entry); | |
662 | spin_unlock_irqrestore(shost->host_lock, flags); | |
663 | ||
664 | blk_run_queue(sdev->request_queue); | |
665 | ||
666 | spin_lock_irqsave(shost->host_lock, flags); | |
667 | if (unlikely(!list_empty(&sdev->starved_entry))) | |
668 | /* | |
669 | * sdev lost a race, and was put back on the | |
670 | * starved list. This is unlikely but without this | |
671 | * in theory we could loop forever. | |
672 | */ | |
673 | break; | |
674 | } | |
675 | spin_unlock_irqrestore(shost->host_lock, flags); | |
676 | ||
677 | blk_run_queue(q); | |
678 | } | |
679 | ||
680 | /* | |
681 | * Function: scsi_requeue_command() | |
682 | * | |
683 | * Purpose: Handle post-processing of completed commands. | |
684 | * | |
685 | * Arguments: q - queue to operate on | |
686 | * cmd - command that may need to be requeued. | |
687 | * | |
688 | * Returns: Nothing | |
689 | * | |
690 | * Notes: After command completion, there may be blocks left | |
691 | * over which weren't finished by the previous command | |
692 | * this can be for a number of reasons - the main one is | |
693 | * I/O errors in the middle of the request, in which case | |
694 | * we need to request the blocks that come after the bad | |
695 | * sector. | |
e91442b6 | 696 | * Notes: Upon return, cmd is a stale pointer. |
1da177e4 LT |
697 | */ |
698 | static void scsi_requeue_command(struct request_queue *q, struct scsi_cmnd *cmd) | |
699 | { | |
e91442b6 | 700 | struct request *req = cmd->request; |
283369cc TH |
701 | unsigned long flags; |
702 | ||
e91442b6 | 703 | scsi_unprep_request(req); |
283369cc | 704 | spin_lock_irqsave(q->queue_lock, flags); |
e91442b6 | 705 | blk_requeue_request(q, req); |
283369cc | 706 | spin_unlock_irqrestore(q->queue_lock, flags); |
1da177e4 LT |
707 | |
708 | scsi_run_queue(q); | |
709 | } | |
710 | ||
711 | void scsi_next_command(struct scsi_cmnd *cmd) | |
712 | { | |
49d7bc64 LT |
713 | struct scsi_device *sdev = cmd->device; |
714 | struct request_queue *q = sdev->request_queue; | |
715 | ||
716 | /* need to hold a reference on the device before we let go of the cmd */ | |
717 | get_device(&sdev->sdev_gendev); | |
1da177e4 LT |
718 | |
719 | scsi_put_command(cmd); | |
720 | scsi_run_queue(q); | |
49d7bc64 LT |
721 | |
722 | /* ok to remove device now */ | |
723 | put_device(&sdev->sdev_gendev); | |
1da177e4 LT |
724 | } |
725 | ||
726 | void scsi_run_host_queues(struct Scsi_Host *shost) | |
727 | { | |
728 | struct scsi_device *sdev; | |
729 | ||
730 | shost_for_each_device(sdev, shost) | |
731 | scsi_run_queue(sdev->request_queue); | |
732 | } | |
733 | ||
734 | /* | |
735 | * Function: scsi_end_request() | |
736 | * | |
737 | * Purpose: Post-processing of completed commands (usually invoked at end | |
738 | * of upper level post-processing and scsi_io_completion). | |
739 | * | |
740 | * Arguments: cmd - command that is complete. | |
741 | * uptodate - 1 if I/O indicates success, <= 0 for I/O error. | |
742 | * bytes - number of bytes of completed I/O | |
743 | * requeue - indicates whether we should requeue leftovers. | |
744 | * | |
745 | * Lock status: Assumed that lock is not held upon entry. | |
746 | * | |
e91442b6 | 747 | * Returns: cmd if requeue required, NULL otherwise. |
1da177e4 LT |
748 | * |
749 | * Notes: This is called for block device requests in order to | |
750 | * mark some number of sectors as complete. | |
751 | * | |
752 | * We are guaranteeing that the request queue will be goosed | |
753 | * at some point during this call. | |
e91442b6 | 754 | * Notes: If cmd was requeued, upon return it will be a stale pointer. |
1da177e4 LT |
755 | */ |
756 | static struct scsi_cmnd *scsi_end_request(struct scsi_cmnd *cmd, int uptodate, | |
757 | int bytes, int requeue) | |
758 | { | |
759 | request_queue_t *q = cmd->device->request_queue; | |
760 | struct request *req = cmd->request; | |
761 | unsigned long flags; | |
762 | ||
763 | /* | |
764 | * If there are blocks left over at the end, set up the command | |
765 | * to queue the remainder of them. | |
766 | */ | |
767 | if (end_that_request_chunk(req, uptodate, bytes)) { | |
768 | int leftover = (req->hard_nr_sectors << 9); | |
769 | ||
770 | if (blk_pc_request(req)) | |
771 | leftover = req->data_len; | |
772 | ||
773 | /* kill remainder if no retrys */ | |
774 | if (!uptodate && blk_noretry_request(req)) | |
775 | end_that_request_chunk(req, 0, leftover); | |
776 | else { | |
e91442b6 | 777 | if (requeue) { |
1da177e4 LT |
778 | /* |
779 | * Bleah. Leftovers again. Stick the | |
780 | * leftovers in the front of the | |
781 | * queue, and goose the queue again. | |
782 | */ | |
783 | scsi_requeue_command(q, cmd); | |
e91442b6 JB |
784 | cmd = NULL; |
785 | } | |
1da177e4 LT |
786 | return cmd; |
787 | } | |
788 | } | |
789 | ||
790 | add_disk_randomness(req->rq_disk); | |
791 | ||
792 | spin_lock_irqsave(q->queue_lock, flags); | |
793 | if (blk_rq_tagged(req)) | |
794 | blk_queue_end_tag(q, req); | |
8ffdc655 | 795 | end_that_request_last(req, uptodate); |
1da177e4 LT |
796 | spin_unlock_irqrestore(q->queue_lock, flags); |
797 | ||
798 | /* | |
799 | * This will goose the queue request function at the end, so we don't | |
800 | * need to worry about launching another command. | |
801 | */ | |
802 | scsi_next_command(cmd); | |
803 | return NULL; | |
804 | } | |
805 | ||
c53033f6 | 806 | static struct scatterlist *scsi_alloc_sgtable(struct scsi_cmnd *cmd, gfp_t gfp_mask) |
1da177e4 LT |
807 | { |
808 | struct scsi_host_sg_pool *sgp; | |
809 | struct scatterlist *sgl; | |
810 | ||
811 | BUG_ON(!cmd->use_sg); | |
812 | ||
813 | switch (cmd->use_sg) { | |
814 | case 1 ... 8: | |
815 | cmd->sglist_len = 0; | |
816 | break; | |
817 | case 9 ... 16: | |
818 | cmd->sglist_len = 1; | |
819 | break; | |
820 | case 17 ... 32: | |
821 | cmd->sglist_len = 2; | |
822 | break; | |
823 | #if (SCSI_MAX_PHYS_SEGMENTS > 32) | |
824 | case 33 ... 64: | |
825 | cmd->sglist_len = 3; | |
826 | break; | |
827 | #if (SCSI_MAX_PHYS_SEGMENTS > 64) | |
828 | case 65 ... 128: | |
829 | cmd->sglist_len = 4; | |
830 | break; | |
831 | #if (SCSI_MAX_PHYS_SEGMENTS > 128) | |
832 | case 129 ... 256: | |
833 | cmd->sglist_len = 5; | |
834 | break; | |
835 | #endif | |
836 | #endif | |
837 | #endif | |
838 | default: | |
839 | return NULL; | |
840 | } | |
841 | ||
842 | sgp = scsi_sg_pools + cmd->sglist_len; | |
843 | sgl = mempool_alloc(sgp->pool, gfp_mask); | |
1da177e4 LT |
844 | return sgl; |
845 | } | |
846 | ||
847 | static void scsi_free_sgtable(struct scatterlist *sgl, int index) | |
848 | { | |
849 | struct scsi_host_sg_pool *sgp; | |
850 | ||
a77e3362 | 851 | BUG_ON(index >= SG_MEMPOOL_NR); |
1da177e4 LT |
852 | |
853 | sgp = scsi_sg_pools + index; | |
854 | mempool_free(sgl, sgp->pool); | |
855 | } | |
856 | ||
857 | /* | |
858 | * Function: scsi_release_buffers() | |
859 | * | |
860 | * Purpose: Completion processing for block device I/O requests. | |
861 | * | |
862 | * Arguments: cmd - command that we are bailing. | |
863 | * | |
864 | * Lock status: Assumed that no lock is held upon entry. | |
865 | * | |
866 | * Returns: Nothing | |
867 | * | |
868 | * Notes: In the event that an upper level driver rejects a | |
869 | * command, we must release resources allocated during | |
870 | * the __init_io() function. Primarily this would involve | |
871 | * the scatter-gather table, and potentially any bounce | |
872 | * buffers. | |
873 | */ | |
874 | static void scsi_release_buffers(struct scsi_cmnd *cmd) | |
875 | { | |
876 | struct request *req = cmd->request; | |
877 | ||
878 | /* | |
879 | * Free up any indirection buffers we allocated for DMA purposes. | |
880 | */ | |
881 | if (cmd->use_sg) | |
882 | scsi_free_sgtable(cmd->request_buffer, cmd->sglist_len); | |
883 | else if (cmd->request_buffer != req->buffer) | |
884 | kfree(cmd->request_buffer); | |
885 | ||
886 | /* | |
887 | * Zero these out. They now point to freed memory, and it is | |
888 | * dangerous to hang onto the pointers. | |
889 | */ | |
890 | cmd->buffer = NULL; | |
891 | cmd->bufflen = 0; | |
892 | cmd->request_buffer = NULL; | |
893 | cmd->request_bufflen = 0; | |
894 | } | |
895 | ||
896 | /* | |
897 | * Function: scsi_io_completion() | |
898 | * | |
899 | * Purpose: Completion processing for block device I/O requests. | |
900 | * | |
901 | * Arguments: cmd - command that is finished. | |
902 | * | |
903 | * Lock status: Assumed that no lock is held upon entry. | |
904 | * | |
905 | * Returns: Nothing | |
906 | * | |
907 | * Notes: This function is matched in terms of capabilities to | |
908 | * the function that created the scatter-gather list. | |
909 | * In other words, if there are no bounce buffers | |
910 | * (the normal case for most drivers), we don't need | |
911 | * the logic to deal with cleaning up afterwards. | |
912 | * | |
913 | * We must do one of several things here: | |
914 | * | |
915 | * a) Call scsi_end_request. This will finish off the | |
916 | * specified number of sectors. If we are done, the | |
917 | * command block will be released, and the queue | |
918 | * function will be goosed. If we are not done, then | |
919 | * scsi_end_request will directly goose the queue. | |
920 | * | |
921 | * b) We can just use scsi_requeue_command() here. This would | |
922 | * be used if we just wanted to retry, for example. | |
923 | */ | |
924 | void scsi_io_completion(struct scsi_cmnd *cmd, unsigned int good_bytes, | |
925 | unsigned int block_bytes) | |
926 | { | |
927 | int result = cmd->result; | |
928 | int this_count = cmd->bufflen; | |
929 | request_queue_t *q = cmd->device->request_queue; | |
930 | struct request *req = cmd->request; | |
931 | int clear_errors = 1; | |
932 | struct scsi_sense_hdr sshdr; | |
933 | int sense_valid = 0; | |
934 | int sense_deferred = 0; | |
935 | ||
1da177e4 LT |
936 | /* |
937 | * Free up any indirection buffers we allocated for DMA purposes. | |
938 | * For the case of a READ, we need to copy the data out of the | |
939 | * bounce buffer and into the real buffer. | |
940 | */ | |
941 | if (cmd->use_sg) | |
942 | scsi_free_sgtable(cmd->buffer, cmd->sglist_len); | |
943 | else if (cmd->buffer != req->buffer) { | |
944 | if (rq_data_dir(req) == READ) { | |
945 | unsigned long flags; | |
946 | char *to = bio_kmap_irq(req->bio, &flags); | |
947 | memcpy(to, cmd->buffer, cmd->bufflen); | |
948 | bio_kunmap_irq(to, &flags); | |
949 | } | |
950 | kfree(cmd->buffer); | |
951 | } | |
952 | ||
953 | if (result) { | |
954 | sense_valid = scsi_command_normalize_sense(cmd, &sshdr); | |
955 | if (sense_valid) | |
956 | sense_deferred = scsi_sense_is_deferred(&sshdr); | |
957 | } | |
958 | if (blk_pc_request(req)) { /* SG_IO ioctl from block level */ | |
959 | req->errors = result; | |
960 | if (result) { | |
961 | clear_errors = 0; | |
962 | if (sense_valid && req->sense) { | |
963 | /* | |
964 | * SG_IO wants current and deferred errors | |
965 | */ | |
966 | int len = 8 + cmd->sense_buffer[7]; | |
967 | ||
968 | if (len > SCSI_SENSE_BUFFERSIZE) | |
969 | len = SCSI_SENSE_BUFFERSIZE; | |
970 | memcpy(req->sense, cmd->sense_buffer, len); | |
971 | req->sense_len = len; | |
972 | } | |
973 | } else | |
974 | req->data_len = cmd->resid; | |
975 | } | |
976 | ||
977 | /* | |
978 | * Zero these out. They now point to freed memory, and it is | |
979 | * dangerous to hang onto the pointers. | |
980 | */ | |
981 | cmd->buffer = NULL; | |
982 | cmd->bufflen = 0; | |
983 | cmd->request_buffer = NULL; | |
984 | cmd->request_bufflen = 0; | |
985 | ||
986 | /* | |
987 | * Next deal with any sectors which we were able to correctly | |
988 | * handle. | |
989 | */ | |
990 | if (good_bytes >= 0) { | |
991 | SCSI_LOG_HLCOMPLETE(1, printk("%ld sectors total, %d bytes done.\n", | |
992 | req->nr_sectors, good_bytes)); | |
993 | SCSI_LOG_HLCOMPLETE(1, printk("use_sg is %d\n", cmd->use_sg)); | |
994 | ||
995 | if (clear_errors) | |
996 | req->errors = 0; | |
997 | /* | |
998 | * If multiple sectors are requested in one buffer, then | |
999 | * they will have been finished off by the first command. | |
1000 | * If not, then we have a multi-buffer command. | |
1001 | * | |
1002 | * If block_bytes != 0, it means we had a medium error | |
1003 | * of some sort, and that we want to mark some number of | |
1004 | * sectors as not uptodate. Thus we want to inhibit | |
1005 | * requeueing right here - we will requeue down below | |
1006 | * when we handle the bad sectors. | |
1007 | */ | |
1da177e4 LT |
1008 | |
1009 | /* | |
e91442b6 JB |
1010 | * If the command completed without error, then either |
1011 | * finish off the rest of the command, or start a new one. | |
1da177e4 | 1012 | */ |
e91442b6 | 1013 | if (scsi_end_request(cmd, 1, good_bytes, result == 0) == NULL) |
1da177e4 | 1014 | return; |
1da177e4 LT |
1015 | } |
1016 | /* | |
1017 | * Now, if we were good little boys and girls, Santa left us a request | |
1018 | * sense buffer. We can extract information from this, so we | |
1019 | * can choose a block to remap, etc. | |
1020 | */ | |
1021 | if (sense_valid && !sense_deferred) { | |
1022 | switch (sshdr.sense_key) { | |
1023 | case UNIT_ATTENTION: | |
1024 | if (cmd->device->removable) { | |
1025 | /* detected disc change. set a bit | |
1026 | * and quietly refuse further access. | |
1027 | */ | |
1028 | cmd->device->changed = 1; | |
e91442b6 | 1029 | scsi_end_request(cmd, 0, |
1da177e4 LT |
1030 | this_count, 1); |
1031 | return; | |
1032 | } else { | |
1033 | /* | |
1034 | * Must have been a power glitch, or a | |
1035 | * bus reset. Could not have been a | |
1036 | * media change, so we just retry the | |
1037 | * request and see what happens. | |
1038 | */ | |
1039 | scsi_requeue_command(q, cmd); | |
1040 | return; | |
1041 | } | |
1042 | break; | |
1043 | case ILLEGAL_REQUEST: | |
1044 | /* | |
1045 | * If we had an ILLEGAL REQUEST returned, then we may | |
1046 | * have performed an unsupported command. The only | |
1047 | * thing this should be would be a ten byte read where | |
1048 | * only a six byte read was supported. Also, on a | |
1049 | * system where READ CAPACITY failed, we may have read | |
1050 | * past the end of the disk. | |
1051 | */ | |
26a68019 JA |
1052 | if ((cmd->device->use_10_for_rw && |
1053 | sshdr.asc == 0x20 && sshdr.ascq == 0x00) && | |
1da177e4 LT |
1054 | (cmd->cmnd[0] == READ_10 || |
1055 | cmd->cmnd[0] == WRITE_10)) { | |
1056 | cmd->device->use_10_for_rw = 0; | |
1057 | /* | |
1058 | * This will cause a retry with a 6-byte | |
1059 | * command. | |
1060 | */ | |
1061 | scsi_requeue_command(q, cmd); | |
1062 | result = 0; | |
1063 | } else { | |
e91442b6 | 1064 | scsi_end_request(cmd, 0, this_count, 1); |
1da177e4 LT |
1065 | return; |
1066 | } | |
1067 | break; | |
1068 | case NOT_READY: | |
1069 | /* | |
1070 | * If the device is in the process of becoming ready, | |
1071 | * retry. | |
1072 | */ | |
1073 | if (sshdr.asc == 0x04 && sshdr.ascq == 0x01) { | |
1074 | scsi_requeue_command(q, cmd); | |
1075 | return; | |
1076 | } | |
3173d8c3 | 1077 | if (!(req->flags & REQ_QUIET)) |
3bf743e7 JG |
1078 | scmd_printk(KERN_INFO, cmd, |
1079 | "Device not ready.\n"); | |
e91442b6 | 1080 | scsi_end_request(cmd, 0, this_count, 1); |
1da177e4 LT |
1081 | return; |
1082 | case VOLUME_OVERFLOW: | |
3173d8c3 | 1083 | if (!(req->flags & REQ_QUIET)) { |
3bf743e7 JG |
1084 | scmd_printk(KERN_INFO, cmd, |
1085 | "Volume overflow, CDB: "); | |
3173d8c3 JB |
1086 | __scsi_print_command(cmd->data_cmnd); |
1087 | scsi_print_sense("", cmd); | |
1088 | } | |
e91442b6 | 1089 | scsi_end_request(cmd, 0, block_bytes, 1); |
1da177e4 LT |
1090 | return; |
1091 | default: | |
1092 | break; | |
1093 | } | |
1094 | } /* driver byte != 0 */ | |
1095 | if (host_byte(result) == DID_RESET) { | |
1096 | /* | |
1097 | * Third party bus reset or reset for error | |
1098 | * recovery reasons. Just retry the request | |
1099 | * and see what happens. | |
1100 | */ | |
1101 | scsi_requeue_command(q, cmd); | |
1102 | return; | |
1103 | } | |
1104 | if (result) { | |
3173d8c3 | 1105 | if (!(req->flags & REQ_QUIET)) { |
3bf743e7 JG |
1106 | scmd_printk(KERN_INFO, cmd, |
1107 | "SCSI error: return code = 0x%x\n", result); | |
3173d8c3 JB |
1108 | |
1109 | if (driver_byte(result) & DRIVER_SENSE) | |
1110 | scsi_print_sense("", cmd); | |
1111 | } | |
1da177e4 LT |
1112 | /* |
1113 | * Mark a single buffer as not uptodate. Queue the remainder. | |
1114 | * We sometimes get this cruft in the event that a medium error | |
1115 | * isn't properly reported. | |
1116 | */ | |
1117 | block_bytes = req->hard_cur_sectors << 9; | |
1118 | if (!block_bytes) | |
1119 | block_bytes = req->data_len; | |
e91442b6 | 1120 | scsi_end_request(cmd, 0, block_bytes, 1); |
1da177e4 LT |
1121 | } |
1122 | } | |
1123 | EXPORT_SYMBOL(scsi_io_completion); | |
1124 | ||
1125 | /* | |
1126 | * Function: scsi_init_io() | |
1127 | * | |
1128 | * Purpose: SCSI I/O initialize function. | |
1129 | * | |
1130 | * Arguments: cmd - Command descriptor we wish to initialize | |
1131 | * | |
1132 | * Returns: 0 on success | |
1133 | * BLKPREP_DEFER if the failure is retryable | |
1134 | * BLKPREP_KILL if the failure is fatal | |
1135 | */ | |
1136 | static int scsi_init_io(struct scsi_cmnd *cmd) | |
1137 | { | |
1138 | struct request *req = cmd->request; | |
1139 | struct scatterlist *sgpnt; | |
1140 | int count; | |
1141 | ||
1142 | /* | |
1143 | * if this is a rq->data based REQ_BLOCK_PC, setup for a non-sg xfer | |
1144 | */ | |
1145 | if ((req->flags & REQ_BLOCK_PC) && !req->bio) { | |
1146 | cmd->request_bufflen = req->data_len; | |
1147 | cmd->request_buffer = req->data; | |
1148 | req->buffer = req->data; | |
1149 | cmd->use_sg = 0; | |
1150 | return 0; | |
1151 | } | |
1152 | ||
1153 | /* | |
1154 | * we used to not use scatter-gather for single segment request, | |
1155 | * but now we do (it makes highmem I/O easier to support without | |
1156 | * kmapping pages) | |
1157 | */ | |
1158 | cmd->use_sg = req->nr_phys_segments; | |
1159 | ||
1160 | /* | |
1161 | * if sg table allocation fails, requeue request later. | |
1162 | */ | |
1163 | sgpnt = scsi_alloc_sgtable(cmd, GFP_ATOMIC); | |
7c72ce81 AS |
1164 | if (unlikely(!sgpnt)) { |
1165 | scsi_unprep_request(req); | |
1da177e4 | 1166 | return BLKPREP_DEFER; |
7c72ce81 | 1167 | } |
1da177e4 LT |
1168 | |
1169 | cmd->request_buffer = (char *) sgpnt; | |
1170 | cmd->request_bufflen = req->nr_sectors << 9; | |
1171 | if (blk_pc_request(req)) | |
1172 | cmd->request_bufflen = req->data_len; | |
1173 | req->buffer = NULL; | |
1174 | ||
1175 | /* | |
1176 | * Next, walk the list, and fill in the addresses and sizes of | |
1177 | * each segment. | |
1178 | */ | |
1179 | count = blk_rq_map_sg(req->q, req, cmd->request_buffer); | |
1180 | ||
1181 | /* | |
1182 | * mapped well, send it off | |
1183 | */ | |
1184 | if (likely(count <= cmd->use_sg)) { | |
1185 | cmd->use_sg = count; | |
1186 | return 0; | |
1187 | } | |
1188 | ||
1189 | printk(KERN_ERR "Incorrect number of segments after building list\n"); | |
1190 | printk(KERN_ERR "counted %d, received %d\n", count, cmd->use_sg); | |
1191 | printk(KERN_ERR "req nr_sec %lu, cur_nr_sec %u\n", req->nr_sectors, | |
1192 | req->current_nr_sectors); | |
1193 | ||
1194 | /* release the command and kill it */ | |
1195 | scsi_release_buffers(cmd); | |
1196 | scsi_put_command(cmd); | |
1197 | return BLKPREP_KILL; | |
1198 | } | |
1199 | ||
1da177e4 LT |
1200 | static int scsi_issue_flush_fn(request_queue_t *q, struct gendisk *disk, |
1201 | sector_t *error_sector) | |
1202 | { | |
1203 | struct scsi_device *sdev = q->queuedata; | |
1204 | struct scsi_driver *drv; | |
1205 | ||
1206 | if (sdev->sdev_state != SDEV_RUNNING) | |
1207 | return -ENXIO; | |
1208 | ||
1209 | drv = *(struct scsi_driver **) disk->private_data; | |
1210 | if (drv->issue_flush) | |
1211 | return drv->issue_flush(&sdev->sdev_gendev, error_sector); | |
1212 | ||
1213 | return -EOPNOTSUPP; | |
1214 | } | |
1215 | ||
776b23a0 | 1216 | static void scsi_blk_pc_done(struct scsi_cmnd *cmd) |
e537a36d JB |
1217 | { |
1218 | BUG_ON(!blk_pc_request(cmd->request)); | |
0d95716d MC |
1219 | /* |
1220 | * This will complete the whole command with uptodate=1 so | |
1221 | * as far as the block layer is concerned the command completed | |
1222 | * successfully. Since this is a REQ_BLOCK_PC command the | |
1223 | * caller should check the request's errors value | |
1224 | */ | |
1225 | scsi_io_completion(cmd, cmd->bufflen, 0); | |
e537a36d JB |
1226 | } |
1227 | ||
776b23a0 | 1228 | static void scsi_setup_blk_pc_cmnd(struct scsi_cmnd *cmd) |
7b16318d JB |
1229 | { |
1230 | struct request *req = cmd->request; | |
1231 | ||
1232 | BUG_ON(sizeof(req->cmd) > sizeof(cmd->cmnd)); | |
1233 | memcpy(cmd->cmnd, req->cmd, sizeof(cmd->cmnd)); | |
1234 | cmd->cmd_len = req->cmd_len; | |
1235 | if (!req->data_len) | |
1236 | cmd->sc_data_direction = DMA_NONE; | |
1237 | else if (rq_data_dir(req) == WRITE) | |
1238 | cmd->sc_data_direction = DMA_TO_DEVICE; | |
1239 | else | |
1240 | cmd->sc_data_direction = DMA_FROM_DEVICE; | |
1241 | ||
1242 | cmd->transfersize = req->data_len; | |
1243 | cmd->allowed = req->retries; | |
1244 | cmd->timeout_per_command = req->timeout; | |
776b23a0 | 1245 | cmd->done = scsi_blk_pc_done; |
7b16318d | 1246 | } |
7b16318d | 1247 | |
1da177e4 LT |
1248 | static int scsi_prep_fn(struct request_queue *q, struct request *req) |
1249 | { | |
1250 | struct scsi_device *sdev = q->queuedata; | |
1251 | struct scsi_cmnd *cmd; | |
1252 | int specials_only = 0; | |
1253 | ||
1254 | /* | |
1255 | * Just check to see if the device is online. If it isn't, we | |
1256 | * refuse to process any commands. The device must be brought | |
1257 | * online before trying any recovery commands | |
1258 | */ | |
1259 | if (unlikely(!scsi_device_online(sdev))) { | |
9ccfc756 JB |
1260 | sdev_printk(KERN_ERR, sdev, |
1261 | "rejecting I/O to offline device\n"); | |
6f16b535 | 1262 | goto kill; |
1da177e4 LT |
1263 | } |
1264 | if (unlikely(sdev->sdev_state != SDEV_RUNNING)) { | |
1265 | /* OK, we're not in a running state don't prep | |
1266 | * user commands */ | |
1267 | if (sdev->sdev_state == SDEV_DEL) { | |
1268 | /* Device is fully deleted, no commands | |
1269 | * at all allowed down */ | |
9ccfc756 JB |
1270 | sdev_printk(KERN_ERR, sdev, |
1271 | "rejecting I/O to dead device\n"); | |
6f16b535 | 1272 | goto kill; |
1da177e4 LT |
1273 | } |
1274 | /* OK, we only allow special commands (i.e. not | |
1275 | * user initiated ones */ | |
1276 | specials_only = sdev->sdev_state; | |
1277 | } | |
1278 | ||
1279 | /* | |
1280 | * Find the actual device driver associated with this command. | |
1281 | * The SPECIAL requests are things like character device or | |
1282 | * ioctls, which did not originate from ll_rw_blk. Note that | |
1283 | * the special field is also used to indicate the cmd for | |
1284 | * the remainder of a partially fulfilled request that can | |
1285 | * come up when there is a medium error. We have to treat | |
1286 | * these two cases differently. We differentiate by looking | |
1287 | * at request->cmd, as this tells us the real story. | |
1288 | */ | |
e537a36d | 1289 | if (req->flags & REQ_SPECIAL && req->special) { |
1da177e4 LT |
1290 | struct scsi_request *sreq = req->special; |
1291 | ||
1292 | if (sreq->sr_magic == SCSI_REQ_MAGIC) { | |
1293 | cmd = scsi_get_command(sreq->sr_device, GFP_ATOMIC); | |
1294 | if (unlikely(!cmd)) | |
1295 | goto defer; | |
1296 | scsi_init_cmd_from_req(cmd, sreq); | |
1297 | } else | |
1298 | cmd = req->special; | |
1299 | } else if (req->flags & (REQ_CMD | REQ_BLOCK_PC)) { | |
1300 | ||
e537a36d | 1301 | if(unlikely(specials_only) && !(req->flags & REQ_SPECIAL)) { |
1da177e4 LT |
1302 | if(specials_only == SDEV_QUIESCE || |
1303 | specials_only == SDEV_BLOCK) | |
6f16b535 | 1304 | goto defer; |
1da177e4 | 1305 | |
9ccfc756 JB |
1306 | sdev_printk(KERN_ERR, sdev, |
1307 | "rejecting I/O to device being removed\n"); | |
6f16b535 | 1308 | goto kill; |
1da177e4 LT |
1309 | } |
1310 | ||
1311 | ||
1312 | /* | |
1313 | * Now try and find a command block that we can use. | |
1314 | */ | |
1315 | if (!req->special) { | |
1316 | cmd = scsi_get_command(sdev, GFP_ATOMIC); | |
1317 | if (unlikely(!cmd)) | |
1318 | goto defer; | |
1319 | } else | |
1320 | cmd = req->special; | |
1321 | ||
1322 | /* pull a tag out of the request if we have one */ | |
1323 | cmd->tag = req->tag; | |
1324 | } else { | |
1325 | blk_dump_rq_flags(req, "SCSI bad req"); | |
6f16b535 | 1326 | goto kill; |
1da177e4 LT |
1327 | } |
1328 | ||
1329 | /* note the overloading of req->special. When the tag | |
1330 | * is active it always means cmd. If the tag goes | |
1331 | * back for re-queueing, it may be reset */ | |
1332 | req->special = cmd; | |
1333 | cmd->request = req; | |
1334 | ||
1335 | /* | |
1336 | * FIXME: drop the lock here because the functions below | |
1337 | * expect to be called without the queue lock held. Also, | |
1338 | * previously, we dequeued the request before dropping the | |
1339 | * lock. We hope REQ_STARTED prevents anything untoward from | |
1340 | * happening now. | |
1341 | */ | |
1342 | if (req->flags & (REQ_CMD | REQ_BLOCK_PC)) { | |
1da177e4 LT |
1343 | int ret; |
1344 | ||
1345 | /* | |
1346 | * This will do a couple of things: | |
1347 | * 1) Fill in the actual SCSI command. | |
1348 | * 2) Fill in any other upper-level specific fields | |
1349 | * (timeout). | |
1350 | * | |
1351 | * If this returns 0, it means that the request failed | |
1352 | * (reading past end of disk, reading offline device, | |
1353 | * etc). This won't actually talk to the device, but | |
1354 | * some kinds of consistency checking may cause the | |
1355 | * request to be rejected immediately. | |
1356 | */ | |
1357 | ||
1358 | /* | |
1359 | * This sets up the scatter-gather table (allocating if | |
1360 | * required). | |
1361 | */ | |
1362 | ret = scsi_init_io(cmd); | |
6f16b535 | 1363 | switch(ret) { |
7c72ce81 | 1364 | /* For BLKPREP_KILL/DEFER the cmd was released */ |
6f16b535 | 1365 | case BLKPREP_KILL: |
6f16b535 MC |
1366 | goto kill; |
1367 | case BLKPREP_DEFER: | |
1368 | goto defer; | |
1369 | } | |
1da177e4 LT |
1370 | |
1371 | /* | |
1372 | * Initialize the actual SCSI command for this request. | |
1373 | */ | |
776b23a0 CH |
1374 | if (req->flags & REQ_BLOCK_PC) { |
1375 | scsi_setup_blk_pc_cmnd(cmd); | |
1376 | } else if (req->rq_disk) { | |
1377 | struct scsi_driver *drv; | |
1378 | ||
e537a36d JB |
1379 | drv = *(struct scsi_driver **)req->rq_disk->private_data; |
1380 | if (unlikely(!drv->init_command(cmd))) { | |
1381 | scsi_release_buffers(cmd); | |
1382 | scsi_put_command(cmd); | |
6f16b535 | 1383 | goto kill; |
e537a36d | 1384 | } |
1da177e4 LT |
1385 | } |
1386 | } | |
1387 | ||
1388 | /* | |
1389 | * The request is now prepped, no need to come back here | |
1390 | */ | |
1391 | req->flags |= REQ_DONTPREP; | |
1392 | return BLKPREP_OK; | |
1393 | ||
1394 | defer: | |
1395 | /* If we defer, the elv_next_request() returns NULL, but the | |
1396 | * queue must be restarted, so we plug here if no returning | |
1397 | * command will automatically do that. */ | |
1398 | if (sdev->device_busy == 0) | |
1399 | blk_plug_device(q); | |
1400 | return BLKPREP_DEFER; | |
6f16b535 MC |
1401 | kill: |
1402 | req->errors = DID_NO_CONNECT << 16; | |
1403 | return BLKPREP_KILL; | |
1da177e4 LT |
1404 | } |
1405 | ||
1406 | /* | |
1407 | * scsi_dev_queue_ready: if we can send requests to sdev, return 1 else | |
1408 | * return 0. | |
1409 | * | |
1410 | * Called with the queue_lock held. | |
1411 | */ | |
1412 | static inline int scsi_dev_queue_ready(struct request_queue *q, | |
1413 | struct scsi_device *sdev) | |
1414 | { | |
1415 | if (sdev->device_busy >= sdev->queue_depth) | |
1416 | return 0; | |
1417 | if (sdev->device_busy == 0 && sdev->device_blocked) { | |
1418 | /* | |
1419 | * unblock after device_blocked iterates to zero | |
1420 | */ | |
1421 | if (--sdev->device_blocked == 0) { | |
1422 | SCSI_LOG_MLQUEUE(3, | |
9ccfc756 JB |
1423 | sdev_printk(KERN_INFO, sdev, |
1424 | "unblocking device at zero depth\n")); | |
1da177e4 LT |
1425 | } else { |
1426 | blk_plug_device(q); | |
1427 | return 0; | |
1428 | } | |
1429 | } | |
1430 | if (sdev->device_blocked) | |
1431 | return 0; | |
1432 | ||
1433 | return 1; | |
1434 | } | |
1435 | ||
1436 | /* | |
1437 | * scsi_host_queue_ready: if we can send requests to shost, return 1 else | |
1438 | * return 0. We must end up running the queue again whenever 0 is | |
1439 | * returned, else IO can hang. | |
1440 | * | |
1441 | * Called with host_lock held. | |
1442 | */ | |
1443 | static inline int scsi_host_queue_ready(struct request_queue *q, | |
1444 | struct Scsi_Host *shost, | |
1445 | struct scsi_device *sdev) | |
1446 | { | |
939647ee | 1447 | if (scsi_host_in_recovery(shost)) |
1da177e4 LT |
1448 | return 0; |
1449 | if (shost->host_busy == 0 && shost->host_blocked) { | |
1450 | /* | |
1451 | * unblock after host_blocked iterates to zero | |
1452 | */ | |
1453 | if (--shost->host_blocked == 0) { | |
1454 | SCSI_LOG_MLQUEUE(3, | |
1455 | printk("scsi%d unblocking host at zero depth\n", | |
1456 | shost->host_no)); | |
1457 | } else { | |
1458 | blk_plug_device(q); | |
1459 | return 0; | |
1460 | } | |
1461 | } | |
1462 | if ((shost->can_queue > 0 && shost->host_busy >= shost->can_queue) || | |
1463 | shost->host_blocked || shost->host_self_blocked) { | |
1464 | if (list_empty(&sdev->starved_entry)) | |
1465 | list_add_tail(&sdev->starved_entry, &shost->starved_list); | |
1466 | return 0; | |
1467 | } | |
1468 | ||
1469 | /* We're OK to process the command, so we can't be starved */ | |
1470 | if (!list_empty(&sdev->starved_entry)) | |
1471 | list_del_init(&sdev->starved_entry); | |
1472 | ||
1473 | return 1; | |
1474 | } | |
1475 | ||
1476 | /* | |
e91442b6 | 1477 | * Kill a request for a dead device |
1da177e4 | 1478 | */ |
e91442b6 | 1479 | static void scsi_kill_request(struct request *req, request_queue_t *q) |
1da177e4 | 1480 | { |
e91442b6 | 1481 | struct scsi_cmnd *cmd = req->special; |
1da177e4 | 1482 | |
788ce43a JB |
1483 | blkdev_dequeue_request(req); |
1484 | ||
e91442b6 JB |
1485 | if (unlikely(cmd == NULL)) { |
1486 | printk(KERN_CRIT "impossible request in %s.\n", | |
1487 | __FUNCTION__); | |
1488 | BUG(); | |
1da177e4 | 1489 | } |
e91442b6 JB |
1490 | |
1491 | scsi_init_cmd_errh(cmd); | |
1492 | cmd->result = DID_NO_CONNECT << 16; | |
1493 | atomic_inc(&cmd->device->iorequest_cnt); | |
1494 | __scsi_done(cmd); | |
1da177e4 LT |
1495 | } |
1496 | ||
1aea6434 JA |
1497 | static void scsi_softirq_done(struct request *rq) |
1498 | { | |
1499 | struct scsi_cmnd *cmd = rq->completion_data; | |
8884efab | 1500 | unsigned long wait_for = (cmd->allowed + 1) * cmd->timeout_per_command; |
1aea6434 JA |
1501 | int disposition; |
1502 | ||
1503 | INIT_LIST_HEAD(&cmd->eh_entry); | |
1504 | ||
1505 | disposition = scsi_decide_disposition(cmd); | |
1506 | if (disposition != SUCCESS && | |
1507 | time_before(cmd->jiffies_at_alloc + wait_for, jiffies)) { | |
1508 | sdev_printk(KERN_ERR, cmd->device, | |
1509 | "timing out command, waited %lus\n", | |
1510 | wait_for/HZ); | |
1511 | disposition = SUCCESS; | |
1512 | } | |
1513 | ||
1514 | scsi_log_completion(cmd, disposition); | |
1515 | ||
1516 | switch (disposition) { | |
1517 | case SUCCESS: | |
1518 | scsi_finish_command(cmd); | |
1519 | break; | |
1520 | case NEEDS_RETRY: | |
1521 | scsi_retry_command(cmd); | |
1522 | break; | |
1523 | case ADD_TO_MLQUEUE: | |
1524 | scsi_queue_insert(cmd, SCSI_MLQUEUE_DEVICE_BUSY); | |
1525 | break; | |
1526 | default: | |
1527 | if (!scsi_eh_scmd_add(cmd, 0)) | |
1528 | scsi_finish_command(cmd); | |
1529 | } | |
1530 | } | |
1531 | ||
1da177e4 LT |
1532 | /* |
1533 | * Function: scsi_request_fn() | |
1534 | * | |
1535 | * Purpose: Main strategy routine for SCSI. | |
1536 | * | |
1537 | * Arguments: q - Pointer to actual queue. | |
1538 | * | |
1539 | * Returns: Nothing | |
1540 | * | |
1541 | * Lock status: IO request lock assumed to be held when called. | |
1542 | */ | |
1543 | static void scsi_request_fn(struct request_queue *q) | |
1544 | { | |
1545 | struct scsi_device *sdev = q->queuedata; | |
1546 | struct Scsi_Host *shost; | |
1547 | struct scsi_cmnd *cmd; | |
1548 | struct request *req; | |
1549 | ||
1550 | if (!sdev) { | |
1551 | printk("scsi: killing requests for dead queue\n"); | |
e91442b6 JB |
1552 | while ((req = elv_next_request(q)) != NULL) |
1553 | scsi_kill_request(req, q); | |
1da177e4 LT |
1554 | return; |
1555 | } | |
1556 | ||
1557 | if(!get_device(&sdev->sdev_gendev)) | |
1558 | /* We must be tearing the block queue down already */ | |
1559 | return; | |
1560 | ||
1561 | /* | |
1562 | * To start with, we keep looping until the queue is empty, or until | |
1563 | * the host is no longer able to accept any more requests. | |
1564 | */ | |
1565 | shost = sdev->host; | |
1566 | while (!blk_queue_plugged(q)) { | |
1567 | int rtn; | |
1568 | /* | |
1569 | * get next queueable request. We do this early to make sure | |
1570 | * that the request is fully prepared even if we cannot | |
1571 | * accept it. | |
1572 | */ | |
1573 | req = elv_next_request(q); | |
1574 | if (!req || !scsi_dev_queue_ready(q, sdev)) | |
1575 | break; | |
1576 | ||
1577 | if (unlikely(!scsi_device_online(sdev))) { | |
9ccfc756 JB |
1578 | sdev_printk(KERN_ERR, sdev, |
1579 | "rejecting I/O to offline device\n"); | |
e91442b6 | 1580 | scsi_kill_request(req, q); |
1da177e4 LT |
1581 | continue; |
1582 | } | |
1583 | ||
1584 | ||
1585 | /* | |
1586 | * Remove the request from the request list. | |
1587 | */ | |
1588 | if (!(blk_queue_tagged(q) && !blk_queue_start_tag(q, req))) | |
1589 | blkdev_dequeue_request(req); | |
1590 | sdev->device_busy++; | |
1591 | ||
1592 | spin_unlock(q->queue_lock); | |
e91442b6 JB |
1593 | cmd = req->special; |
1594 | if (unlikely(cmd == NULL)) { | |
1595 | printk(KERN_CRIT "impossible request in %s.\n" | |
1596 | "please mail a stack trace to " | |
1597 | "linux-scsi@vger.kernel.org", | |
1598 | __FUNCTION__); | |
1599 | BUG(); | |
1600 | } | |
1da177e4 LT |
1601 | spin_lock(shost->host_lock); |
1602 | ||
1603 | if (!scsi_host_queue_ready(q, shost, sdev)) | |
1604 | goto not_ready; | |
1605 | if (sdev->single_lun) { | |
1606 | if (scsi_target(sdev)->starget_sdev_user && | |
1607 | scsi_target(sdev)->starget_sdev_user != sdev) | |
1608 | goto not_ready; | |
1609 | scsi_target(sdev)->starget_sdev_user = sdev; | |
1610 | } | |
1611 | shost->host_busy++; | |
1612 | ||
1613 | /* | |
1614 | * XXX(hch): This is rather suboptimal, scsi_dispatch_cmd will | |
1615 | * take the lock again. | |
1616 | */ | |
1617 | spin_unlock_irq(shost->host_lock); | |
1618 | ||
1da177e4 LT |
1619 | /* |
1620 | * Finally, initialize any error handling parameters, and set up | |
1621 | * the timers for timeouts. | |
1622 | */ | |
1623 | scsi_init_cmd_errh(cmd); | |
1624 | ||
1625 | /* | |
1626 | * Dispatch the command to the low-level driver. | |
1627 | */ | |
1628 | rtn = scsi_dispatch_cmd(cmd); | |
1629 | spin_lock_irq(q->queue_lock); | |
1630 | if(rtn) { | |
1631 | /* we're refusing the command; because of | |
1632 | * the way locks get dropped, we need to | |
1633 | * check here if plugging is required */ | |
1634 | if(sdev->device_busy == 0) | |
1635 | blk_plug_device(q); | |
1636 | ||
1637 | break; | |
1638 | } | |
1639 | } | |
1640 | ||
1641 | goto out; | |
1642 | ||
1643 | not_ready: | |
1644 | spin_unlock_irq(shost->host_lock); | |
1645 | ||
1646 | /* | |
1647 | * lock q, handle tag, requeue req, and decrement device_busy. We | |
1648 | * must return with queue_lock held. | |
1649 | * | |
1650 | * Decrementing device_busy without checking it is OK, as all such | |
1651 | * cases (host limits or settings) should run the queue at some | |
1652 | * later time. | |
1653 | */ | |
1654 | spin_lock_irq(q->queue_lock); | |
1655 | blk_requeue_request(q, req); | |
1656 | sdev->device_busy--; | |
1657 | if(sdev->device_busy == 0) | |
1658 | blk_plug_device(q); | |
1659 | out: | |
1660 | /* must be careful here...if we trigger the ->remove() function | |
1661 | * we cannot be holding the q lock */ | |
1662 | spin_unlock_irq(q->queue_lock); | |
1663 | put_device(&sdev->sdev_gendev); | |
1664 | spin_lock_irq(q->queue_lock); | |
1665 | } | |
1666 | ||
1667 | u64 scsi_calculate_bounce_limit(struct Scsi_Host *shost) | |
1668 | { | |
1669 | struct device *host_dev; | |
1670 | u64 bounce_limit = 0xffffffff; | |
1671 | ||
1672 | if (shost->unchecked_isa_dma) | |
1673 | return BLK_BOUNCE_ISA; | |
1674 | /* | |
1675 | * Platforms with virtual-DMA translation | |
1676 | * hardware have no practical limit. | |
1677 | */ | |
1678 | if (!PCI_DMA_BUS_IS_PHYS) | |
1679 | return BLK_BOUNCE_ANY; | |
1680 | ||
1681 | host_dev = scsi_get_device(shost); | |
1682 | if (host_dev && host_dev->dma_mask) | |
1683 | bounce_limit = *host_dev->dma_mask; | |
1684 | ||
1685 | return bounce_limit; | |
1686 | } | |
1687 | EXPORT_SYMBOL(scsi_calculate_bounce_limit); | |
1688 | ||
1689 | struct request_queue *scsi_alloc_queue(struct scsi_device *sdev) | |
1690 | { | |
1691 | struct Scsi_Host *shost = sdev->host; | |
1692 | struct request_queue *q; | |
1693 | ||
152587de | 1694 | q = blk_init_queue(scsi_request_fn, NULL); |
1da177e4 LT |
1695 | if (!q) |
1696 | return NULL; | |
1697 | ||
1698 | blk_queue_prep_rq(q, scsi_prep_fn); | |
1699 | ||
1700 | blk_queue_max_hw_segments(q, shost->sg_tablesize); | |
1701 | blk_queue_max_phys_segments(q, SCSI_MAX_PHYS_SEGMENTS); | |
1702 | blk_queue_max_sectors(q, shost->max_sectors); | |
1703 | blk_queue_bounce_limit(q, scsi_calculate_bounce_limit(shost)); | |
1704 | blk_queue_segment_boundary(q, shost->dma_boundary); | |
1705 | blk_queue_issue_flush_fn(q, scsi_issue_flush_fn); | |
1aea6434 | 1706 | blk_queue_softirq_done(q, scsi_softirq_done); |
1da177e4 | 1707 | |
1da177e4 LT |
1708 | if (!shost->use_clustering) |
1709 | clear_bit(QUEUE_FLAG_CLUSTER, &q->queue_flags); | |
1710 | return q; | |
1711 | } | |
1712 | ||
1713 | void scsi_free_queue(struct request_queue *q) | |
1714 | { | |
1715 | blk_cleanup_queue(q); | |
1716 | } | |
1717 | ||
1718 | /* | |
1719 | * Function: scsi_block_requests() | |
1720 | * | |
1721 | * Purpose: Utility function used by low-level drivers to prevent further | |
1722 | * commands from being queued to the device. | |
1723 | * | |
1724 | * Arguments: shost - Host in question | |
1725 | * | |
1726 | * Returns: Nothing | |
1727 | * | |
1728 | * Lock status: No locks are assumed held. | |
1729 | * | |
1730 | * Notes: There is no timer nor any other means by which the requests | |
1731 | * get unblocked other than the low-level driver calling | |
1732 | * scsi_unblock_requests(). | |
1733 | */ | |
1734 | void scsi_block_requests(struct Scsi_Host *shost) | |
1735 | { | |
1736 | shost->host_self_blocked = 1; | |
1737 | } | |
1738 | EXPORT_SYMBOL(scsi_block_requests); | |
1739 | ||
1740 | /* | |
1741 | * Function: scsi_unblock_requests() | |
1742 | * | |
1743 | * Purpose: Utility function used by low-level drivers to allow further | |
1744 | * commands from being queued to the device. | |
1745 | * | |
1746 | * Arguments: shost - Host in question | |
1747 | * | |
1748 | * Returns: Nothing | |
1749 | * | |
1750 | * Lock status: No locks are assumed held. | |
1751 | * | |
1752 | * Notes: There is no timer nor any other means by which the requests | |
1753 | * get unblocked other than the low-level driver calling | |
1754 | * scsi_unblock_requests(). | |
1755 | * | |
1756 | * This is done as an API function so that changes to the | |
1757 | * internals of the scsi mid-layer won't require wholesale | |
1758 | * changes to drivers that use this feature. | |
1759 | */ | |
1760 | void scsi_unblock_requests(struct Scsi_Host *shost) | |
1761 | { | |
1762 | shost->host_self_blocked = 0; | |
1763 | scsi_run_host_queues(shost); | |
1764 | } | |
1765 | EXPORT_SYMBOL(scsi_unblock_requests); | |
1766 | ||
1767 | int __init scsi_init_queue(void) | |
1768 | { | |
1769 | int i; | |
1770 | ||
aa7b5cd7 MC |
1771 | scsi_io_context_cache = kmem_cache_create("scsi_io_context", |
1772 | sizeof(struct scsi_io_context), | |
1773 | 0, 0, NULL, NULL); | |
1774 | if (!scsi_io_context_cache) { | |
1775 | printk(KERN_ERR "SCSI: can't init scsi io context cache\n"); | |
1776 | return -ENOMEM; | |
1777 | } | |
1778 | ||
1da177e4 LT |
1779 | for (i = 0; i < SG_MEMPOOL_NR; i++) { |
1780 | struct scsi_host_sg_pool *sgp = scsi_sg_pools + i; | |
1781 | int size = sgp->size * sizeof(struct scatterlist); | |
1782 | ||
1783 | sgp->slab = kmem_cache_create(sgp->name, size, 0, | |
1784 | SLAB_HWCACHE_ALIGN, NULL, NULL); | |
1785 | if (!sgp->slab) { | |
1786 | printk(KERN_ERR "SCSI: can't init sg slab %s\n", | |
1787 | sgp->name); | |
1788 | } | |
1789 | ||
93d2341c MD |
1790 | sgp->pool = mempool_create_slab_pool(SG_MEMPOOL_SIZE, |
1791 | sgp->slab); | |
1da177e4 LT |
1792 | if (!sgp->pool) { |
1793 | printk(KERN_ERR "SCSI: can't init sg mempool %s\n", | |
1794 | sgp->name); | |
1795 | } | |
1796 | } | |
1797 | ||
1798 | return 0; | |
1799 | } | |
1800 | ||
1801 | void scsi_exit_queue(void) | |
1802 | { | |
1803 | int i; | |
1804 | ||
aa7b5cd7 MC |
1805 | kmem_cache_destroy(scsi_io_context_cache); |
1806 | ||
1da177e4 LT |
1807 | for (i = 0; i < SG_MEMPOOL_NR; i++) { |
1808 | struct scsi_host_sg_pool *sgp = scsi_sg_pools + i; | |
1809 | mempool_destroy(sgp->pool); | |
1810 | kmem_cache_destroy(sgp->slab); | |
1811 | } | |
1812 | } | |
5baba830 JB |
1813 | |
1814 | /** | |
1815 | * scsi_mode_select - issue a mode select | |
1816 | * @sdev: SCSI device to be queried | |
1817 | * @pf: Page format bit (1 == standard, 0 == vendor specific) | |
1818 | * @sp: Save page bit (0 == don't save, 1 == save) | |
1819 | * @modepage: mode page being requested | |
1820 | * @buffer: request buffer (may not be smaller than eight bytes) | |
1821 | * @len: length of request buffer. | |
1822 | * @timeout: command timeout | |
1823 | * @retries: number of retries before failing | |
1824 | * @data: returns a structure abstracting the mode header data | |
1825 | * @sense: place to put sense data (or NULL if no sense to be collected). | |
1826 | * must be SCSI_SENSE_BUFFERSIZE big. | |
1827 | * | |
1828 | * Returns zero if successful; negative error number or scsi | |
1829 | * status on error | |
1830 | * | |
1831 | */ | |
1832 | int | |
1833 | scsi_mode_select(struct scsi_device *sdev, int pf, int sp, int modepage, | |
1834 | unsigned char *buffer, int len, int timeout, int retries, | |
1835 | struct scsi_mode_data *data, struct scsi_sense_hdr *sshdr) | |
1836 | { | |
1837 | unsigned char cmd[10]; | |
1838 | unsigned char *real_buffer; | |
1839 | int ret; | |
1840 | ||
1841 | memset(cmd, 0, sizeof(cmd)); | |
1842 | cmd[1] = (pf ? 0x10 : 0) | (sp ? 0x01 : 0); | |
1843 | ||
1844 | if (sdev->use_10_for_ms) { | |
1845 | if (len > 65535) | |
1846 | return -EINVAL; | |
1847 | real_buffer = kmalloc(8 + len, GFP_KERNEL); | |
1848 | if (!real_buffer) | |
1849 | return -ENOMEM; | |
1850 | memcpy(real_buffer + 8, buffer, len); | |
1851 | len += 8; | |
1852 | real_buffer[0] = 0; | |
1853 | real_buffer[1] = 0; | |
1854 | real_buffer[2] = data->medium_type; | |
1855 | real_buffer[3] = data->device_specific; | |
1856 | real_buffer[4] = data->longlba ? 0x01 : 0; | |
1857 | real_buffer[5] = 0; | |
1858 | real_buffer[6] = data->block_descriptor_length >> 8; | |
1859 | real_buffer[7] = data->block_descriptor_length; | |
1860 | ||
1861 | cmd[0] = MODE_SELECT_10; | |
1862 | cmd[7] = len >> 8; | |
1863 | cmd[8] = len; | |
1864 | } else { | |
1865 | if (len > 255 || data->block_descriptor_length > 255 || | |
1866 | data->longlba) | |
1867 | return -EINVAL; | |
1868 | ||
1869 | real_buffer = kmalloc(4 + len, GFP_KERNEL); | |
1870 | if (!real_buffer) | |
1871 | return -ENOMEM; | |
1872 | memcpy(real_buffer + 4, buffer, len); | |
1873 | len += 4; | |
1874 | real_buffer[0] = 0; | |
1875 | real_buffer[1] = data->medium_type; | |
1876 | real_buffer[2] = data->device_specific; | |
1877 | real_buffer[3] = data->block_descriptor_length; | |
1878 | ||
1879 | ||
1880 | cmd[0] = MODE_SELECT; | |
1881 | cmd[4] = len; | |
1882 | } | |
1883 | ||
1884 | ret = scsi_execute_req(sdev, cmd, DMA_TO_DEVICE, real_buffer, len, | |
1885 | sshdr, timeout, retries); | |
1886 | kfree(real_buffer); | |
1887 | return ret; | |
1888 | } | |
1889 | EXPORT_SYMBOL_GPL(scsi_mode_select); | |
1890 | ||
1da177e4 | 1891 | /** |
ea73a9f2 | 1892 | * scsi_mode_sense - issue a mode sense, falling back from 10 to |
1da177e4 | 1893 | * six bytes if necessary. |
1cf72699 | 1894 | * @sdev: SCSI device to be queried |
1da177e4 LT |
1895 | * @dbd: set if mode sense will allow block descriptors to be returned |
1896 | * @modepage: mode page being requested | |
1897 | * @buffer: request buffer (may not be smaller than eight bytes) | |
1898 | * @len: length of request buffer. | |
1899 | * @timeout: command timeout | |
1900 | * @retries: number of retries before failing | |
1901 | * @data: returns a structure abstracting the mode header data | |
1cf72699 JB |
1902 | * @sense: place to put sense data (or NULL if no sense to be collected). |
1903 | * must be SCSI_SENSE_BUFFERSIZE big. | |
1da177e4 LT |
1904 | * |
1905 | * Returns zero if unsuccessful, or the header offset (either 4 | |
1906 | * or 8 depending on whether a six or ten byte command was | |
1907 | * issued) if successful. | |
1908 | **/ | |
1909 | int | |
1cf72699 | 1910 | scsi_mode_sense(struct scsi_device *sdev, int dbd, int modepage, |
1da177e4 | 1911 | unsigned char *buffer, int len, int timeout, int retries, |
5baba830 JB |
1912 | struct scsi_mode_data *data, struct scsi_sense_hdr *sshdr) |
1913 | { | |
1da177e4 LT |
1914 | unsigned char cmd[12]; |
1915 | int use_10_for_ms; | |
1916 | int header_length; | |
1cf72699 | 1917 | int result; |
ea73a9f2 | 1918 | struct scsi_sense_hdr my_sshdr; |
1da177e4 LT |
1919 | |
1920 | memset(data, 0, sizeof(*data)); | |
1921 | memset(&cmd[0], 0, 12); | |
1922 | cmd[1] = dbd & 0x18; /* allows DBD and LLBA bits */ | |
1923 | cmd[2] = modepage; | |
1924 | ||
ea73a9f2 JB |
1925 | /* caller might not be interested in sense, but we need it */ |
1926 | if (!sshdr) | |
1927 | sshdr = &my_sshdr; | |
1928 | ||
1da177e4 | 1929 | retry: |
1cf72699 | 1930 | use_10_for_ms = sdev->use_10_for_ms; |
1da177e4 LT |
1931 | |
1932 | if (use_10_for_ms) { | |
1933 | if (len < 8) | |
1934 | len = 8; | |
1935 | ||
1936 | cmd[0] = MODE_SENSE_10; | |
1937 | cmd[8] = len; | |
1938 | header_length = 8; | |
1939 | } else { | |
1940 | if (len < 4) | |
1941 | len = 4; | |
1942 | ||
1943 | cmd[0] = MODE_SENSE; | |
1944 | cmd[4] = len; | |
1945 | header_length = 4; | |
1946 | } | |
1947 | ||
1da177e4 LT |
1948 | memset(buffer, 0, len); |
1949 | ||
1cf72699 | 1950 | result = scsi_execute_req(sdev, cmd, DMA_FROM_DEVICE, buffer, len, |
ea73a9f2 | 1951 | sshdr, timeout, retries); |
1da177e4 LT |
1952 | |
1953 | /* This code looks awful: what it's doing is making sure an | |
1954 | * ILLEGAL REQUEST sense return identifies the actual command | |
1955 | * byte as the problem. MODE_SENSE commands can return | |
1956 | * ILLEGAL REQUEST if the code page isn't supported */ | |
1957 | ||
1cf72699 JB |
1958 | if (use_10_for_ms && !scsi_status_is_good(result) && |
1959 | (driver_byte(result) & DRIVER_SENSE)) { | |
ea73a9f2 JB |
1960 | if (scsi_sense_valid(sshdr)) { |
1961 | if ((sshdr->sense_key == ILLEGAL_REQUEST) && | |
1962 | (sshdr->asc == 0x20) && (sshdr->ascq == 0)) { | |
1da177e4 LT |
1963 | /* |
1964 | * Invalid command operation code | |
1965 | */ | |
1cf72699 | 1966 | sdev->use_10_for_ms = 0; |
1da177e4 LT |
1967 | goto retry; |
1968 | } | |
1969 | } | |
1970 | } | |
1971 | ||
1cf72699 | 1972 | if(scsi_status_is_good(result)) { |
6d73c851 AV |
1973 | if (unlikely(buffer[0] == 0x86 && buffer[1] == 0x0b && |
1974 | (modepage == 6 || modepage == 8))) { | |
1975 | /* Initio breakage? */ | |
1976 | header_length = 0; | |
1977 | data->length = 13; | |
1978 | data->medium_type = 0; | |
1979 | data->device_specific = 0; | |
1980 | data->longlba = 0; | |
1981 | data->block_descriptor_length = 0; | |
1982 | } else if(use_10_for_ms) { | |
1da177e4 LT |
1983 | data->length = buffer[0]*256 + buffer[1] + 2; |
1984 | data->medium_type = buffer[2]; | |
1985 | data->device_specific = buffer[3]; | |
1986 | data->longlba = buffer[4] & 0x01; | |
1987 | data->block_descriptor_length = buffer[6]*256 | |
1988 | + buffer[7]; | |
1989 | } else { | |
1990 | data->length = buffer[0] + 1; | |
1991 | data->medium_type = buffer[1]; | |
1992 | data->device_specific = buffer[2]; | |
1993 | data->block_descriptor_length = buffer[3]; | |
1994 | } | |
6d73c851 | 1995 | data->header_length = header_length; |
1da177e4 LT |
1996 | } |
1997 | ||
1cf72699 | 1998 | return result; |
1da177e4 LT |
1999 | } |
2000 | EXPORT_SYMBOL(scsi_mode_sense); | |
2001 | ||
2002 | int | |
2003 | scsi_test_unit_ready(struct scsi_device *sdev, int timeout, int retries) | |
2004 | { | |
1da177e4 LT |
2005 | char cmd[] = { |
2006 | TEST_UNIT_READY, 0, 0, 0, 0, 0, | |
2007 | }; | |
ea73a9f2 | 2008 | struct scsi_sense_hdr sshdr; |
1da177e4 LT |
2009 | int result; |
2010 | ||
ea73a9f2 | 2011 | result = scsi_execute_req(sdev, cmd, DMA_NONE, NULL, 0, &sshdr, |
1cf72699 | 2012 | timeout, retries); |
1da177e4 | 2013 | |
1cf72699 | 2014 | if ((driver_byte(result) & DRIVER_SENSE) && sdev->removable) { |
1da177e4 | 2015 | |
ea73a9f2 | 2016 | if ((scsi_sense_valid(&sshdr)) && |
1da177e4 LT |
2017 | ((sshdr.sense_key == UNIT_ATTENTION) || |
2018 | (sshdr.sense_key == NOT_READY))) { | |
2019 | sdev->changed = 1; | |
1cf72699 | 2020 | result = 0; |
1da177e4 LT |
2021 | } |
2022 | } | |
1da177e4 LT |
2023 | return result; |
2024 | } | |
2025 | EXPORT_SYMBOL(scsi_test_unit_ready); | |
2026 | ||
2027 | /** | |
2028 | * scsi_device_set_state - Take the given device through the device | |
2029 | * state model. | |
2030 | * @sdev: scsi device to change the state of. | |
2031 | * @state: state to change to. | |
2032 | * | |
2033 | * Returns zero if unsuccessful or an error if the requested | |
2034 | * transition is illegal. | |
2035 | **/ | |
2036 | int | |
2037 | scsi_device_set_state(struct scsi_device *sdev, enum scsi_device_state state) | |
2038 | { | |
2039 | enum scsi_device_state oldstate = sdev->sdev_state; | |
2040 | ||
2041 | if (state == oldstate) | |
2042 | return 0; | |
2043 | ||
2044 | switch (state) { | |
2045 | case SDEV_CREATED: | |
2046 | /* There are no legal states that come back to | |
2047 | * created. This is the manually initialised start | |
2048 | * state */ | |
2049 | goto illegal; | |
2050 | ||
2051 | case SDEV_RUNNING: | |
2052 | switch (oldstate) { | |
2053 | case SDEV_CREATED: | |
2054 | case SDEV_OFFLINE: | |
2055 | case SDEV_QUIESCE: | |
2056 | case SDEV_BLOCK: | |
2057 | break; | |
2058 | default: | |
2059 | goto illegal; | |
2060 | } | |
2061 | break; | |
2062 | ||
2063 | case SDEV_QUIESCE: | |
2064 | switch (oldstate) { | |
2065 | case SDEV_RUNNING: | |
2066 | case SDEV_OFFLINE: | |
2067 | break; | |
2068 | default: | |
2069 | goto illegal; | |
2070 | } | |
2071 | break; | |
2072 | ||
2073 | case SDEV_OFFLINE: | |
2074 | switch (oldstate) { | |
2075 | case SDEV_CREATED: | |
2076 | case SDEV_RUNNING: | |
2077 | case SDEV_QUIESCE: | |
2078 | case SDEV_BLOCK: | |
2079 | break; | |
2080 | default: | |
2081 | goto illegal; | |
2082 | } | |
2083 | break; | |
2084 | ||
2085 | case SDEV_BLOCK: | |
2086 | switch (oldstate) { | |
2087 | case SDEV_CREATED: | |
2088 | case SDEV_RUNNING: | |
2089 | break; | |
2090 | default: | |
2091 | goto illegal; | |
2092 | } | |
2093 | break; | |
2094 | ||
2095 | case SDEV_CANCEL: | |
2096 | switch (oldstate) { | |
2097 | case SDEV_CREATED: | |
2098 | case SDEV_RUNNING: | |
2099 | case SDEV_OFFLINE: | |
2100 | case SDEV_BLOCK: | |
2101 | break; | |
2102 | default: | |
2103 | goto illegal; | |
2104 | } | |
2105 | break; | |
2106 | ||
2107 | case SDEV_DEL: | |
2108 | switch (oldstate) { | |
2109 | case SDEV_CANCEL: | |
2110 | break; | |
2111 | default: | |
2112 | goto illegal; | |
2113 | } | |
2114 | break; | |
2115 | ||
2116 | } | |
2117 | sdev->sdev_state = state; | |
2118 | return 0; | |
2119 | ||
2120 | illegal: | |
2121 | SCSI_LOG_ERROR_RECOVERY(1, | |
9ccfc756 JB |
2122 | sdev_printk(KERN_ERR, sdev, |
2123 | "Illegal state transition %s->%s\n", | |
2124 | scsi_device_state_name(oldstate), | |
2125 | scsi_device_state_name(state)) | |
1da177e4 LT |
2126 | ); |
2127 | return -EINVAL; | |
2128 | } | |
2129 | EXPORT_SYMBOL(scsi_device_set_state); | |
2130 | ||
2131 | /** | |
2132 | * scsi_device_quiesce - Block user issued commands. | |
2133 | * @sdev: scsi device to quiesce. | |
2134 | * | |
2135 | * This works by trying to transition to the SDEV_QUIESCE state | |
2136 | * (which must be a legal transition). When the device is in this | |
2137 | * state, only special requests will be accepted, all others will | |
2138 | * be deferred. Since special requests may also be requeued requests, | |
2139 | * a successful return doesn't guarantee the device will be | |
2140 | * totally quiescent. | |
2141 | * | |
2142 | * Must be called with user context, may sleep. | |
2143 | * | |
2144 | * Returns zero if unsuccessful or an error if not. | |
2145 | **/ | |
2146 | int | |
2147 | scsi_device_quiesce(struct scsi_device *sdev) | |
2148 | { | |
2149 | int err = scsi_device_set_state(sdev, SDEV_QUIESCE); | |
2150 | if (err) | |
2151 | return err; | |
2152 | ||
2153 | scsi_run_queue(sdev->request_queue); | |
2154 | while (sdev->device_busy) { | |
2155 | msleep_interruptible(200); | |
2156 | scsi_run_queue(sdev->request_queue); | |
2157 | } | |
2158 | return 0; | |
2159 | } | |
2160 | EXPORT_SYMBOL(scsi_device_quiesce); | |
2161 | ||
2162 | /** | |
2163 | * scsi_device_resume - Restart user issued commands to a quiesced device. | |
2164 | * @sdev: scsi device to resume. | |
2165 | * | |
2166 | * Moves the device from quiesced back to running and restarts the | |
2167 | * queues. | |
2168 | * | |
2169 | * Must be called with user context, may sleep. | |
2170 | **/ | |
2171 | void | |
2172 | scsi_device_resume(struct scsi_device *sdev) | |
2173 | { | |
2174 | if(scsi_device_set_state(sdev, SDEV_RUNNING)) | |
2175 | return; | |
2176 | scsi_run_queue(sdev->request_queue); | |
2177 | } | |
2178 | EXPORT_SYMBOL(scsi_device_resume); | |
2179 | ||
2180 | static void | |
2181 | device_quiesce_fn(struct scsi_device *sdev, void *data) | |
2182 | { | |
2183 | scsi_device_quiesce(sdev); | |
2184 | } | |
2185 | ||
2186 | void | |
2187 | scsi_target_quiesce(struct scsi_target *starget) | |
2188 | { | |
2189 | starget_for_each_device(starget, NULL, device_quiesce_fn); | |
2190 | } | |
2191 | EXPORT_SYMBOL(scsi_target_quiesce); | |
2192 | ||
2193 | static void | |
2194 | device_resume_fn(struct scsi_device *sdev, void *data) | |
2195 | { | |
2196 | scsi_device_resume(sdev); | |
2197 | } | |
2198 | ||
2199 | void | |
2200 | scsi_target_resume(struct scsi_target *starget) | |
2201 | { | |
2202 | starget_for_each_device(starget, NULL, device_resume_fn); | |
2203 | } | |
2204 | EXPORT_SYMBOL(scsi_target_resume); | |
2205 | ||
2206 | /** | |
2207 | * scsi_internal_device_block - internal function to put a device | |
2208 | * temporarily into the SDEV_BLOCK state | |
2209 | * @sdev: device to block | |
2210 | * | |
2211 | * Block request made by scsi lld's to temporarily stop all | |
2212 | * scsi commands on the specified device. Called from interrupt | |
2213 | * or normal process context. | |
2214 | * | |
2215 | * Returns zero if successful or error if not | |
2216 | * | |
2217 | * Notes: | |
2218 | * This routine transitions the device to the SDEV_BLOCK state | |
2219 | * (which must be a legal transition). When the device is in this | |
2220 | * state, all commands are deferred until the scsi lld reenables | |
2221 | * the device with scsi_device_unblock or device_block_tmo fires. | |
2222 | * This routine assumes the host_lock is held on entry. | |
2223 | **/ | |
2224 | int | |
2225 | scsi_internal_device_block(struct scsi_device *sdev) | |
2226 | { | |
2227 | request_queue_t *q = sdev->request_queue; | |
2228 | unsigned long flags; | |
2229 | int err = 0; | |
2230 | ||
2231 | err = scsi_device_set_state(sdev, SDEV_BLOCK); | |
2232 | if (err) | |
2233 | return err; | |
2234 | ||
2235 | /* | |
2236 | * The device has transitioned to SDEV_BLOCK. Stop the | |
2237 | * block layer from calling the midlayer with this device's | |
2238 | * request queue. | |
2239 | */ | |
2240 | spin_lock_irqsave(q->queue_lock, flags); | |
2241 | blk_stop_queue(q); | |
2242 | spin_unlock_irqrestore(q->queue_lock, flags); | |
2243 | ||
2244 | return 0; | |
2245 | } | |
2246 | EXPORT_SYMBOL_GPL(scsi_internal_device_block); | |
2247 | ||
2248 | /** | |
2249 | * scsi_internal_device_unblock - resume a device after a block request | |
2250 | * @sdev: device to resume | |
2251 | * | |
2252 | * Called by scsi lld's or the midlayer to restart the device queue | |
2253 | * for the previously suspended scsi device. Called from interrupt or | |
2254 | * normal process context. | |
2255 | * | |
2256 | * Returns zero if successful or error if not. | |
2257 | * | |
2258 | * Notes: | |
2259 | * This routine transitions the device to the SDEV_RUNNING state | |
2260 | * (which must be a legal transition) allowing the midlayer to | |
2261 | * goose the queue for this device. This routine assumes the | |
2262 | * host_lock is held upon entry. | |
2263 | **/ | |
2264 | int | |
2265 | scsi_internal_device_unblock(struct scsi_device *sdev) | |
2266 | { | |
2267 | request_queue_t *q = sdev->request_queue; | |
2268 | int err; | |
2269 | unsigned long flags; | |
2270 | ||
2271 | /* | |
2272 | * Try to transition the scsi device to SDEV_RUNNING | |
2273 | * and goose the device queue if successful. | |
2274 | */ | |
2275 | err = scsi_device_set_state(sdev, SDEV_RUNNING); | |
2276 | if (err) | |
2277 | return err; | |
2278 | ||
2279 | spin_lock_irqsave(q->queue_lock, flags); | |
2280 | blk_start_queue(q); | |
2281 | spin_unlock_irqrestore(q->queue_lock, flags); | |
2282 | ||
2283 | return 0; | |
2284 | } | |
2285 | EXPORT_SYMBOL_GPL(scsi_internal_device_unblock); | |
2286 | ||
2287 | static void | |
2288 | device_block(struct scsi_device *sdev, void *data) | |
2289 | { | |
2290 | scsi_internal_device_block(sdev); | |
2291 | } | |
2292 | ||
2293 | static int | |
2294 | target_block(struct device *dev, void *data) | |
2295 | { | |
2296 | if (scsi_is_target_device(dev)) | |
2297 | starget_for_each_device(to_scsi_target(dev), NULL, | |
2298 | device_block); | |
2299 | return 0; | |
2300 | } | |
2301 | ||
2302 | void | |
2303 | scsi_target_block(struct device *dev) | |
2304 | { | |
2305 | if (scsi_is_target_device(dev)) | |
2306 | starget_for_each_device(to_scsi_target(dev), NULL, | |
2307 | device_block); | |
2308 | else | |
2309 | device_for_each_child(dev, NULL, target_block); | |
2310 | } | |
2311 | EXPORT_SYMBOL_GPL(scsi_target_block); | |
2312 | ||
2313 | static void | |
2314 | device_unblock(struct scsi_device *sdev, void *data) | |
2315 | { | |
2316 | scsi_internal_device_unblock(sdev); | |
2317 | } | |
2318 | ||
2319 | static int | |
2320 | target_unblock(struct device *dev, void *data) | |
2321 | { | |
2322 | if (scsi_is_target_device(dev)) | |
2323 | starget_for_each_device(to_scsi_target(dev), NULL, | |
2324 | device_unblock); | |
2325 | return 0; | |
2326 | } | |
2327 | ||
2328 | void | |
2329 | scsi_target_unblock(struct device *dev) | |
2330 | { | |
2331 | if (scsi_is_target_device(dev)) | |
2332 | starget_for_each_device(to_scsi_target(dev), NULL, | |
2333 | device_unblock); | |
2334 | else | |
2335 | device_for_each_child(dev, NULL, target_unblock); | |
2336 | } | |
2337 | EXPORT_SYMBOL_GPL(scsi_target_unblock); |