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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) { |
286f3e13 | 289 | sense = kmalloc(SCSI_SENSE_BUFFERSIZE, GFP_NOIO); |
ea73a9f2 JB |
290 | if (!sense) |
291 | return DRIVER_ERROR << 24; | |
e514385b | 292 | memset(sense, 0, SCSI_SENSE_BUFFERSIZE); |
ea73a9f2 | 293 | } |
1ccb48bb | 294 | result = scsi_execute(sdev, cmd, data_direction, buffer, bufflen, |
ea73a9f2 JB |
295 | sense, timeout, retries, 0); |
296 | if (sshdr) | |
e514385b | 297 | scsi_normalize_sense(sense, SCSI_SENSE_BUFFERSIZE, sshdr); |
ea73a9f2 JB |
298 | |
299 | kfree(sense); | |
300 | return result; | |
301 | } | |
302 | EXPORT_SYMBOL(scsi_execute_req); | |
303 | ||
6e68af66 MC |
304 | struct scsi_io_context { |
305 | void *data; | |
306 | void (*done)(void *data, char *sense, int result, int resid); | |
307 | char sense[SCSI_SENSE_BUFFERSIZE]; | |
308 | }; | |
309 | ||
aa7b5cd7 MC |
310 | static kmem_cache_t *scsi_io_context_cache; |
311 | ||
e650c305 | 312 | static void scsi_end_async(struct request *req, int uptodate) |
6e68af66 MC |
313 | { |
314 | struct scsi_io_context *sioc = req->end_io_data; | |
315 | ||
316 | if (sioc->done) | |
317 | sioc->done(sioc->data, sioc->sense, req->errors, req->data_len); | |
318 | ||
aa7b5cd7 | 319 | kmem_cache_free(scsi_io_context_cache, sioc); |
6e68af66 MC |
320 | __blk_put_request(req->q, req); |
321 | } | |
322 | ||
323 | static int scsi_merge_bio(struct request *rq, struct bio *bio) | |
324 | { | |
325 | struct request_queue *q = rq->q; | |
326 | ||
327 | bio->bi_flags &= ~(1 << BIO_SEG_VALID); | |
328 | if (rq_data_dir(rq) == WRITE) | |
329 | bio->bi_rw |= (1 << BIO_RW); | |
330 | blk_queue_bounce(q, &bio); | |
331 | ||
332 | if (!rq->bio) | |
333 | blk_rq_bio_prep(q, rq, bio); | |
334 | else if (!q->back_merge_fn(q, rq, bio)) | |
335 | return -EINVAL; | |
336 | else { | |
337 | rq->biotail->bi_next = bio; | |
338 | rq->biotail = bio; | |
339 | rq->hard_nr_sectors += bio_sectors(bio); | |
340 | rq->nr_sectors = rq->hard_nr_sectors; | |
341 | } | |
342 | ||
343 | return 0; | |
344 | } | |
345 | ||
346 | static int scsi_bi_endio(struct bio *bio, unsigned int bytes_done, int error) | |
347 | { | |
348 | if (bio->bi_size) | |
349 | return 1; | |
350 | ||
351 | bio_put(bio); | |
352 | return 0; | |
353 | } | |
354 | ||
355 | /** | |
356 | * scsi_req_map_sg - map a scatterlist into a request | |
357 | * @rq: request to fill | |
358 | * @sg: scatterlist | |
359 | * @nsegs: number of elements | |
360 | * @bufflen: len of buffer | |
361 | * @gfp: memory allocation flags | |
362 | * | |
363 | * scsi_req_map_sg maps a scatterlist into a request so that the | |
364 | * request can be sent to the block layer. We do not trust the scatterlist | |
365 | * sent to use, as some ULDs use that struct to only organize the pages. | |
366 | */ | |
367 | static int scsi_req_map_sg(struct request *rq, struct scatterlist *sgl, | |
368 | int nsegs, unsigned bufflen, gfp_t gfp) | |
369 | { | |
370 | struct request_queue *q = rq->q; | |
371 | int nr_pages = (bufflen + PAGE_SIZE - 1) >> PAGE_SHIFT; | |
372 | unsigned int data_len = 0, len, bytes, off; | |
373 | struct page *page; | |
374 | struct bio *bio = NULL; | |
375 | int i, err, nr_vecs = 0; | |
376 | ||
377 | for (i = 0; i < nsegs; i++) { | |
378 | page = sgl[i].page; | |
379 | off = sgl[i].offset; | |
380 | len = sgl[i].length; | |
381 | data_len += len; | |
382 | ||
383 | while (len > 0) { | |
384 | bytes = min_t(unsigned int, len, PAGE_SIZE - off); | |
385 | ||
386 | if (!bio) { | |
387 | nr_vecs = min_t(int, BIO_MAX_PAGES, nr_pages); | |
388 | nr_pages -= nr_vecs; | |
389 | ||
390 | bio = bio_alloc(gfp, nr_vecs); | |
391 | if (!bio) { | |
392 | err = -ENOMEM; | |
393 | goto free_bios; | |
394 | } | |
395 | bio->bi_end_io = scsi_bi_endio; | |
396 | } | |
397 | ||
398 | if (bio_add_pc_page(q, bio, page, bytes, off) != | |
399 | bytes) { | |
400 | bio_put(bio); | |
401 | err = -EINVAL; | |
402 | goto free_bios; | |
403 | } | |
404 | ||
405 | if (bio->bi_vcnt >= nr_vecs) { | |
406 | err = scsi_merge_bio(rq, bio); | |
407 | if (err) { | |
408 | bio_endio(bio, bio->bi_size, 0); | |
409 | goto free_bios; | |
410 | } | |
411 | bio = NULL; | |
412 | } | |
413 | ||
414 | page++; | |
415 | len -= bytes; | |
416 | off = 0; | |
417 | } | |
418 | } | |
419 | ||
420 | rq->buffer = rq->data = NULL; | |
421 | rq->data_len = data_len; | |
422 | return 0; | |
423 | ||
424 | free_bios: | |
425 | while ((bio = rq->bio) != NULL) { | |
426 | rq->bio = bio->bi_next; | |
427 | /* | |
428 | * call endio instead of bio_put incase it was bounced | |
429 | */ | |
430 | bio_endio(bio, bio->bi_size, 0); | |
431 | } | |
432 | ||
433 | return err; | |
434 | } | |
435 | ||
436 | /** | |
437 | * scsi_execute_async - insert request | |
438 | * @sdev: scsi device | |
439 | * @cmd: scsi command | |
bb1d1073 | 440 | * @cmd_len: length of scsi cdb |
6e68af66 MC |
441 | * @data_direction: data direction |
442 | * @buffer: data buffer (this can be a kernel buffer or scatterlist) | |
443 | * @bufflen: len of buffer | |
444 | * @use_sg: if buffer is a scatterlist this is the number of elements | |
445 | * @timeout: request timeout in seconds | |
446 | * @retries: number of times to retry request | |
447 | * @flags: or into request flags | |
448 | **/ | |
449 | int scsi_execute_async(struct scsi_device *sdev, const unsigned char *cmd, | |
bb1d1073 | 450 | int cmd_len, int data_direction, void *buffer, unsigned bufflen, |
6e68af66 MC |
451 | int use_sg, int timeout, int retries, void *privdata, |
452 | void (*done)(void *, char *, int, int), gfp_t gfp) | |
453 | { | |
454 | struct request *req; | |
455 | struct scsi_io_context *sioc; | |
456 | int err = 0; | |
457 | int write = (data_direction == DMA_TO_DEVICE); | |
458 | ||
aa7b5cd7 | 459 | sioc = kmem_cache_alloc(scsi_io_context_cache, gfp); |
6e68af66 MC |
460 | if (!sioc) |
461 | return DRIVER_ERROR << 24; | |
aa7b5cd7 | 462 | memset(sioc, 0, sizeof(*sioc)); |
6e68af66 MC |
463 | |
464 | req = blk_get_request(sdev->request_queue, write, gfp); | |
465 | if (!req) | |
466 | goto free_sense; | |
defd94b7 | 467 | req->flags |= REQ_BLOCK_PC | REQ_QUIET; |
6e68af66 MC |
468 | |
469 | if (use_sg) | |
470 | err = scsi_req_map_sg(req, buffer, use_sg, bufflen, gfp); | |
471 | else if (bufflen) | |
472 | err = blk_rq_map_kern(req->q, req, buffer, bufflen, gfp); | |
473 | ||
474 | if (err) | |
475 | goto free_req; | |
476 | ||
bb1d1073 | 477 | req->cmd_len = cmd_len; |
6e68af66 MC |
478 | memcpy(req->cmd, cmd, req->cmd_len); |
479 | req->sense = sioc->sense; | |
480 | req->sense_len = 0; | |
481 | req->timeout = timeout; | |
17e01f21 | 482 | req->retries = retries; |
6e68af66 MC |
483 | req->end_io_data = sioc; |
484 | ||
485 | sioc->data = privdata; | |
486 | sioc->done = done; | |
487 | ||
488 | blk_execute_rq_nowait(req->q, NULL, req, 1, scsi_end_async); | |
489 | return 0; | |
490 | ||
491 | free_req: | |
492 | blk_put_request(req); | |
493 | free_sense: | |
494 | kfree(sioc); | |
495 | return DRIVER_ERROR << 24; | |
496 | } | |
497 | EXPORT_SYMBOL_GPL(scsi_execute_async); | |
498 | ||
1da177e4 LT |
499 | /* |
500 | * Function: scsi_init_cmd_errh() | |
501 | * | |
502 | * Purpose: Initialize cmd fields related to error handling. | |
503 | * | |
504 | * Arguments: cmd - command that is ready to be queued. | |
505 | * | |
506 | * Returns: Nothing | |
507 | * | |
508 | * Notes: This function has the job of initializing a number of | |
509 | * fields related to error handling. Typically this will | |
510 | * be called once for each command, as required. | |
511 | */ | |
512 | static int scsi_init_cmd_errh(struct scsi_cmnd *cmd) | |
513 | { | |
1da177e4 | 514 | cmd->serial_number = 0; |
1da177e4 LT |
515 | |
516 | memset(cmd->sense_buffer, 0, sizeof cmd->sense_buffer); | |
517 | ||
518 | if (cmd->cmd_len == 0) | |
519 | cmd->cmd_len = COMMAND_SIZE(cmd->cmnd[0]); | |
520 | ||
521 | /* | |
522 | * We need saved copies of a number of fields - this is because | |
523 | * error handling may need to overwrite these with different values | |
524 | * to run different commands, and once error handling is complete, | |
525 | * we will need to restore these values prior to running the actual | |
526 | * command. | |
527 | */ | |
528 | cmd->old_use_sg = cmd->use_sg; | |
529 | cmd->old_cmd_len = cmd->cmd_len; | |
530 | cmd->sc_old_data_direction = cmd->sc_data_direction; | |
531 | cmd->old_underflow = cmd->underflow; | |
532 | memcpy(cmd->data_cmnd, cmd->cmnd, sizeof(cmd->cmnd)); | |
533 | cmd->buffer = cmd->request_buffer; | |
534 | cmd->bufflen = cmd->request_bufflen; | |
1da177e4 LT |
535 | |
536 | return 1; | |
537 | } | |
538 | ||
539 | /* | |
540 | * Function: scsi_setup_cmd_retry() | |
541 | * | |
542 | * Purpose: Restore the command state for a retry | |
543 | * | |
544 | * Arguments: cmd - command to be restored | |
545 | * | |
546 | * Returns: Nothing | |
547 | * | |
548 | * Notes: Immediately prior to retrying a command, we need | |
549 | * to restore certain fields that we saved above. | |
550 | */ | |
551 | void scsi_setup_cmd_retry(struct scsi_cmnd *cmd) | |
552 | { | |
553 | memcpy(cmd->cmnd, cmd->data_cmnd, sizeof(cmd->data_cmnd)); | |
554 | cmd->request_buffer = cmd->buffer; | |
555 | cmd->request_bufflen = cmd->bufflen; | |
556 | cmd->use_sg = cmd->old_use_sg; | |
557 | cmd->cmd_len = cmd->old_cmd_len; | |
558 | cmd->sc_data_direction = cmd->sc_old_data_direction; | |
559 | cmd->underflow = cmd->old_underflow; | |
560 | } | |
561 | ||
562 | void scsi_device_unbusy(struct scsi_device *sdev) | |
563 | { | |
564 | struct Scsi_Host *shost = sdev->host; | |
565 | unsigned long flags; | |
566 | ||
567 | spin_lock_irqsave(shost->host_lock, flags); | |
568 | shost->host_busy--; | |
939647ee | 569 | if (unlikely(scsi_host_in_recovery(shost) && |
1da177e4 LT |
570 | shost->host_failed)) |
571 | scsi_eh_wakeup(shost); | |
572 | spin_unlock(shost->host_lock); | |
152587de | 573 | spin_lock(sdev->request_queue->queue_lock); |
1da177e4 | 574 | sdev->device_busy--; |
152587de | 575 | spin_unlock_irqrestore(sdev->request_queue->queue_lock, flags); |
1da177e4 LT |
576 | } |
577 | ||
578 | /* | |
579 | * Called for single_lun devices on IO completion. Clear starget_sdev_user, | |
580 | * and call blk_run_queue for all the scsi_devices on the target - | |
581 | * including current_sdev first. | |
582 | * | |
583 | * Called with *no* scsi locks held. | |
584 | */ | |
585 | static void scsi_single_lun_run(struct scsi_device *current_sdev) | |
586 | { | |
587 | struct Scsi_Host *shost = current_sdev->host; | |
588 | struct scsi_device *sdev, *tmp; | |
589 | struct scsi_target *starget = scsi_target(current_sdev); | |
590 | unsigned long flags; | |
591 | ||
592 | spin_lock_irqsave(shost->host_lock, flags); | |
593 | starget->starget_sdev_user = NULL; | |
594 | spin_unlock_irqrestore(shost->host_lock, flags); | |
595 | ||
596 | /* | |
597 | * Call blk_run_queue for all LUNs on the target, starting with | |
598 | * current_sdev. We race with others (to set starget_sdev_user), | |
599 | * but in most cases, we will be first. Ideally, each LU on the | |
600 | * target would get some limited time or requests on the target. | |
601 | */ | |
602 | blk_run_queue(current_sdev->request_queue); | |
603 | ||
604 | spin_lock_irqsave(shost->host_lock, flags); | |
605 | if (starget->starget_sdev_user) | |
606 | goto out; | |
607 | list_for_each_entry_safe(sdev, tmp, &starget->devices, | |
608 | same_target_siblings) { | |
609 | if (sdev == current_sdev) | |
610 | continue; | |
611 | if (scsi_device_get(sdev)) | |
612 | continue; | |
613 | ||
614 | spin_unlock_irqrestore(shost->host_lock, flags); | |
615 | blk_run_queue(sdev->request_queue); | |
616 | spin_lock_irqsave(shost->host_lock, flags); | |
617 | ||
618 | scsi_device_put(sdev); | |
619 | } | |
620 | out: | |
621 | spin_unlock_irqrestore(shost->host_lock, flags); | |
622 | } | |
623 | ||
624 | /* | |
625 | * Function: scsi_run_queue() | |
626 | * | |
627 | * Purpose: Select a proper request queue to serve next | |
628 | * | |
629 | * Arguments: q - last request's queue | |
630 | * | |
631 | * Returns: Nothing | |
632 | * | |
633 | * Notes: The previous command was completely finished, start | |
634 | * a new one if possible. | |
635 | */ | |
636 | static void scsi_run_queue(struct request_queue *q) | |
637 | { | |
638 | struct scsi_device *sdev = q->queuedata; | |
639 | struct Scsi_Host *shost = sdev->host; | |
640 | unsigned long flags; | |
641 | ||
642 | if (sdev->single_lun) | |
643 | scsi_single_lun_run(sdev); | |
644 | ||
645 | spin_lock_irqsave(shost->host_lock, flags); | |
646 | while (!list_empty(&shost->starved_list) && | |
647 | !shost->host_blocked && !shost->host_self_blocked && | |
648 | !((shost->can_queue > 0) && | |
649 | (shost->host_busy >= shost->can_queue))) { | |
650 | /* | |
651 | * As long as shost is accepting commands and we have | |
652 | * starved queues, call blk_run_queue. scsi_request_fn | |
653 | * drops the queue_lock and can add us back to the | |
654 | * starved_list. | |
655 | * | |
656 | * host_lock protects the starved_list and starved_entry. | |
657 | * scsi_request_fn must get the host_lock before checking | |
658 | * or modifying starved_list or starved_entry. | |
659 | */ | |
660 | sdev = list_entry(shost->starved_list.next, | |
661 | struct scsi_device, starved_entry); | |
662 | list_del_init(&sdev->starved_entry); | |
663 | spin_unlock_irqrestore(shost->host_lock, flags); | |
664 | ||
665 | blk_run_queue(sdev->request_queue); | |
666 | ||
667 | spin_lock_irqsave(shost->host_lock, flags); | |
668 | if (unlikely(!list_empty(&sdev->starved_entry))) | |
669 | /* | |
670 | * sdev lost a race, and was put back on the | |
671 | * starved list. This is unlikely but without this | |
672 | * in theory we could loop forever. | |
673 | */ | |
674 | break; | |
675 | } | |
676 | spin_unlock_irqrestore(shost->host_lock, flags); | |
677 | ||
678 | blk_run_queue(q); | |
679 | } | |
680 | ||
681 | /* | |
682 | * Function: scsi_requeue_command() | |
683 | * | |
684 | * Purpose: Handle post-processing of completed commands. | |
685 | * | |
686 | * Arguments: q - queue to operate on | |
687 | * cmd - command that may need to be requeued. | |
688 | * | |
689 | * Returns: Nothing | |
690 | * | |
691 | * Notes: After command completion, there may be blocks left | |
692 | * over which weren't finished by the previous command | |
693 | * this can be for a number of reasons - the main one is | |
694 | * I/O errors in the middle of the request, in which case | |
695 | * we need to request the blocks that come after the bad | |
696 | * sector. | |
e91442b6 | 697 | * Notes: Upon return, cmd is a stale pointer. |
1da177e4 LT |
698 | */ |
699 | static void scsi_requeue_command(struct request_queue *q, struct scsi_cmnd *cmd) | |
700 | { | |
e91442b6 | 701 | struct request *req = cmd->request; |
283369cc TH |
702 | unsigned long flags; |
703 | ||
e91442b6 | 704 | scsi_unprep_request(req); |
283369cc | 705 | spin_lock_irqsave(q->queue_lock, flags); |
e91442b6 | 706 | blk_requeue_request(q, req); |
283369cc | 707 | spin_unlock_irqrestore(q->queue_lock, flags); |
1da177e4 LT |
708 | |
709 | scsi_run_queue(q); | |
710 | } | |
711 | ||
712 | void scsi_next_command(struct scsi_cmnd *cmd) | |
713 | { | |
49d7bc64 LT |
714 | struct scsi_device *sdev = cmd->device; |
715 | struct request_queue *q = sdev->request_queue; | |
716 | ||
717 | /* need to hold a reference on the device before we let go of the cmd */ | |
718 | get_device(&sdev->sdev_gendev); | |
1da177e4 LT |
719 | |
720 | scsi_put_command(cmd); | |
721 | scsi_run_queue(q); | |
49d7bc64 LT |
722 | |
723 | /* ok to remove device now */ | |
724 | put_device(&sdev->sdev_gendev); | |
1da177e4 LT |
725 | } |
726 | ||
727 | void scsi_run_host_queues(struct Scsi_Host *shost) | |
728 | { | |
729 | struct scsi_device *sdev; | |
730 | ||
731 | shost_for_each_device(sdev, shost) | |
732 | scsi_run_queue(sdev->request_queue); | |
733 | } | |
734 | ||
735 | /* | |
736 | * Function: scsi_end_request() | |
737 | * | |
738 | * Purpose: Post-processing of completed commands (usually invoked at end | |
739 | * of upper level post-processing and scsi_io_completion). | |
740 | * | |
741 | * Arguments: cmd - command that is complete. | |
742 | * uptodate - 1 if I/O indicates success, <= 0 for I/O error. | |
743 | * bytes - number of bytes of completed I/O | |
744 | * requeue - indicates whether we should requeue leftovers. | |
745 | * | |
746 | * Lock status: Assumed that lock is not held upon entry. | |
747 | * | |
e91442b6 | 748 | * Returns: cmd if requeue required, NULL otherwise. |
1da177e4 LT |
749 | * |
750 | * Notes: This is called for block device requests in order to | |
751 | * mark some number of sectors as complete. | |
752 | * | |
753 | * We are guaranteeing that the request queue will be goosed | |
754 | * at some point during this call. | |
e91442b6 | 755 | * Notes: If cmd was requeued, upon return it will be a stale pointer. |
1da177e4 LT |
756 | */ |
757 | static struct scsi_cmnd *scsi_end_request(struct scsi_cmnd *cmd, int uptodate, | |
758 | int bytes, int requeue) | |
759 | { | |
760 | request_queue_t *q = cmd->device->request_queue; | |
761 | struct request *req = cmd->request; | |
762 | unsigned long flags; | |
763 | ||
764 | /* | |
765 | * If there are blocks left over at the end, set up the command | |
766 | * to queue the remainder of them. | |
767 | */ | |
768 | if (end_that_request_chunk(req, uptodate, bytes)) { | |
769 | int leftover = (req->hard_nr_sectors << 9); | |
770 | ||
771 | if (blk_pc_request(req)) | |
772 | leftover = req->data_len; | |
773 | ||
774 | /* kill remainder if no retrys */ | |
775 | if (!uptodate && blk_noretry_request(req)) | |
776 | end_that_request_chunk(req, 0, leftover); | |
777 | else { | |
e91442b6 | 778 | if (requeue) { |
1da177e4 LT |
779 | /* |
780 | * Bleah. Leftovers again. Stick the | |
781 | * leftovers in the front of the | |
782 | * queue, and goose the queue again. | |
783 | */ | |
784 | scsi_requeue_command(q, cmd); | |
e91442b6 JB |
785 | cmd = NULL; |
786 | } | |
1da177e4 LT |
787 | return cmd; |
788 | } | |
789 | } | |
790 | ||
791 | add_disk_randomness(req->rq_disk); | |
792 | ||
793 | spin_lock_irqsave(q->queue_lock, flags); | |
794 | if (blk_rq_tagged(req)) | |
795 | blk_queue_end_tag(q, req); | |
8ffdc655 | 796 | end_that_request_last(req, uptodate); |
1da177e4 LT |
797 | spin_unlock_irqrestore(q->queue_lock, flags); |
798 | ||
799 | /* | |
800 | * This will goose the queue request function at the end, so we don't | |
801 | * need to worry about launching another command. | |
802 | */ | |
803 | scsi_next_command(cmd); | |
804 | return NULL; | |
805 | } | |
806 | ||
c53033f6 | 807 | static struct scatterlist *scsi_alloc_sgtable(struct scsi_cmnd *cmd, gfp_t gfp_mask) |
1da177e4 LT |
808 | { |
809 | struct scsi_host_sg_pool *sgp; | |
810 | struct scatterlist *sgl; | |
811 | ||
812 | BUG_ON(!cmd->use_sg); | |
813 | ||
814 | switch (cmd->use_sg) { | |
815 | case 1 ... 8: | |
816 | cmd->sglist_len = 0; | |
817 | break; | |
818 | case 9 ... 16: | |
819 | cmd->sglist_len = 1; | |
820 | break; | |
821 | case 17 ... 32: | |
822 | cmd->sglist_len = 2; | |
823 | break; | |
824 | #if (SCSI_MAX_PHYS_SEGMENTS > 32) | |
825 | case 33 ... 64: | |
826 | cmd->sglist_len = 3; | |
827 | break; | |
828 | #if (SCSI_MAX_PHYS_SEGMENTS > 64) | |
829 | case 65 ... 128: | |
830 | cmd->sglist_len = 4; | |
831 | break; | |
832 | #if (SCSI_MAX_PHYS_SEGMENTS > 128) | |
833 | case 129 ... 256: | |
834 | cmd->sglist_len = 5; | |
835 | break; | |
836 | #endif | |
837 | #endif | |
838 | #endif | |
839 | default: | |
840 | return NULL; | |
841 | } | |
842 | ||
843 | sgp = scsi_sg_pools + cmd->sglist_len; | |
844 | sgl = mempool_alloc(sgp->pool, gfp_mask); | |
1da177e4 LT |
845 | return sgl; |
846 | } | |
847 | ||
848 | static void scsi_free_sgtable(struct scatterlist *sgl, int index) | |
849 | { | |
850 | struct scsi_host_sg_pool *sgp; | |
851 | ||
a77e3362 | 852 | BUG_ON(index >= SG_MEMPOOL_NR); |
1da177e4 LT |
853 | |
854 | sgp = scsi_sg_pools + index; | |
855 | mempool_free(sgl, sgp->pool); | |
856 | } | |
857 | ||
858 | /* | |
859 | * Function: scsi_release_buffers() | |
860 | * | |
861 | * Purpose: Completion processing for block device I/O requests. | |
862 | * | |
863 | * Arguments: cmd - command that we are bailing. | |
864 | * | |
865 | * Lock status: Assumed that no lock is held upon entry. | |
866 | * | |
867 | * Returns: Nothing | |
868 | * | |
869 | * Notes: In the event that an upper level driver rejects a | |
870 | * command, we must release resources allocated during | |
871 | * the __init_io() function. Primarily this would involve | |
872 | * the scatter-gather table, and potentially any bounce | |
873 | * buffers. | |
874 | */ | |
875 | static void scsi_release_buffers(struct scsi_cmnd *cmd) | |
876 | { | |
877 | struct request *req = cmd->request; | |
878 | ||
879 | /* | |
880 | * Free up any indirection buffers we allocated for DMA purposes. | |
881 | */ | |
882 | if (cmd->use_sg) | |
883 | scsi_free_sgtable(cmd->request_buffer, cmd->sglist_len); | |
884 | else if (cmd->request_buffer != req->buffer) | |
885 | kfree(cmd->request_buffer); | |
886 | ||
887 | /* | |
888 | * Zero these out. They now point to freed memory, and it is | |
889 | * dangerous to hang onto the pointers. | |
890 | */ | |
891 | cmd->buffer = NULL; | |
892 | cmd->bufflen = 0; | |
893 | cmd->request_buffer = NULL; | |
894 | cmd->request_bufflen = 0; | |
895 | } | |
896 | ||
897 | /* | |
898 | * Function: scsi_io_completion() | |
899 | * | |
900 | * Purpose: Completion processing for block device I/O requests. | |
901 | * | |
902 | * Arguments: cmd - command that is finished. | |
903 | * | |
904 | * Lock status: Assumed that no lock is held upon entry. | |
905 | * | |
906 | * Returns: Nothing | |
907 | * | |
908 | * Notes: This function is matched in terms of capabilities to | |
909 | * the function that created the scatter-gather list. | |
910 | * In other words, if there are no bounce buffers | |
911 | * (the normal case for most drivers), we don't need | |
912 | * the logic to deal with cleaning up afterwards. | |
913 | * | |
914 | * We must do one of several things here: | |
915 | * | |
916 | * a) Call scsi_end_request. This will finish off the | |
917 | * specified number of sectors. If we are done, the | |
918 | * command block will be released, and the queue | |
919 | * function will be goosed. If we are not done, then | |
920 | * scsi_end_request will directly goose the queue. | |
921 | * | |
922 | * b) We can just use scsi_requeue_command() here. This would | |
923 | * be used if we just wanted to retry, for example. | |
924 | */ | |
925 | void scsi_io_completion(struct scsi_cmnd *cmd, unsigned int good_bytes, | |
926 | unsigned int block_bytes) | |
927 | { | |
928 | int result = cmd->result; | |
929 | int this_count = cmd->bufflen; | |
930 | request_queue_t *q = cmd->device->request_queue; | |
931 | struct request *req = cmd->request; | |
932 | int clear_errors = 1; | |
933 | struct scsi_sense_hdr sshdr; | |
934 | int sense_valid = 0; | |
935 | int sense_deferred = 0; | |
936 | ||
1da177e4 LT |
937 | /* |
938 | * Free up any indirection buffers we allocated for DMA purposes. | |
939 | * For the case of a READ, we need to copy the data out of the | |
940 | * bounce buffer and into the real buffer. | |
941 | */ | |
942 | if (cmd->use_sg) | |
943 | scsi_free_sgtable(cmd->buffer, cmd->sglist_len); | |
944 | else if (cmd->buffer != req->buffer) { | |
945 | if (rq_data_dir(req) == READ) { | |
946 | unsigned long flags; | |
947 | char *to = bio_kmap_irq(req->bio, &flags); | |
948 | memcpy(to, cmd->buffer, cmd->bufflen); | |
949 | bio_kunmap_irq(to, &flags); | |
950 | } | |
951 | kfree(cmd->buffer); | |
952 | } | |
953 | ||
954 | if (result) { | |
955 | sense_valid = scsi_command_normalize_sense(cmd, &sshdr); | |
956 | if (sense_valid) | |
957 | sense_deferred = scsi_sense_is_deferred(&sshdr); | |
958 | } | |
959 | if (blk_pc_request(req)) { /* SG_IO ioctl from block level */ | |
960 | req->errors = result; | |
961 | if (result) { | |
962 | clear_errors = 0; | |
963 | if (sense_valid && req->sense) { | |
964 | /* | |
965 | * SG_IO wants current and deferred errors | |
966 | */ | |
967 | int len = 8 + cmd->sense_buffer[7]; | |
968 | ||
969 | if (len > SCSI_SENSE_BUFFERSIZE) | |
970 | len = SCSI_SENSE_BUFFERSIZE; | |
971 | memcpy(req->sense, cmd->sense_buffer, len); | |
972 | req->sense_len = len; | |
973 | } | |
974 | } else | |
975 | req->data_len = cmd->resid; | |
976 | } | |
977 | ||
978 | /* | |
979 | * Zero these out. They now point to freed memory, and it is | |
980 | * dangerous to hang onto the pointers. | |
981 | */ | |
982 | cmd->buffer = NULL; | |
983 | cmd->bufflen = 0; | |
984 | cmd->request_buffer = NULL; | |
985 | cmd->request_bufflen = 0; | |
986 | ||
987 | /* | |
988 | * Next deal with any sectors which we were able to correctly | |
989 | * handle. | |
990 | */ | |
991 | if (good_bytes >= 0) { | |
992 | SCSI_LOG_HLCOMPLETE(1, printk("%ld sectors total, %d bytes done.\n", | |
993 | req->nr_sectors, good_bytes)); | |
994 | SCSI_LOG_HLCOMPLETE(1, printk("use_sg is %d\n", cmd->use_sg)); | |
995 | ||
996 | if (clear_errors) | |
997 | req->errors = 0; | |
998 | /* | |
999 | * If multiple sectors are requested in one buffer, then | |
1000 | * they will have been finished off by the first command. | |
1001 | * If not, then we have a multi-buffer command. | |
1002 | * | |
1003 | * If block_bytes != 0, it means we had a medium error | |
1004 | * of some sort, and that we want to mark some number of | |
1005 | * sectors as not uptodate. Thus we want to inhibit | |
1006 | * requeueing right here - we will requeue down below | |
1007 | * when we handle the bad sectors. | |
1008 | */ | |
1da177e4 LT |
1009 | |
1010 | /* | |
e91442b6 JB |
1011 | * If the command completed without error, then either |
1012 | * finish off the rest of the command, or start a new one. | |
1da177e4 | 1013 | */ |
e91442b6 | 1014 | if (scsi_end_request(cmd, 1, good_bytes, result == 0) == NULL) |
1da177e4 | 1015 | return; |
1da177e4 LT |
1016 | } |
1017 | /* | |
1018 | * Now, if we were good little boys and girls, Santa left us a request | |
1019 | * sense buffer. We can extract information from this, so we | |
1020 | * can choose a block to remap, etc. | |
1021 | */ | |
1022 | if (sense_valid && !sense_deferred) { | |
1023 | switch (sshdr.sense_key) { | |
1024 | case UNIT_ATTENTION: | |
1025 | if (cmd->device->removable) { | |
1026 | /* detected disc change. set a bit | |
1027 | * and quietly refuse further access. | |
1028 | */ | |
1029 | cmd->device->changed = 1; | |
e91442b6 | 1030 | scsi_end_request(cmd, 0, |
1da177e4 LT |
1031 | this_count, 1); |
1032 | return; | |
1033 | } else { | |
1034 | /* | |
1035 | * Must have been a power glitch, or a | |
1036 | * bus reset. Could not have been a | |
1037 | * media change, so we just retry the | |
1038 | * request and see what happens. | |
1039 | */ | |
1040 | scsi_requeue_command(q, cmd); | |
1041 | return; | |
1042 | } | |
1043 | break; | |
1044 | case ILLEGAL_REQUEST: | |
1045 | /* | |
1046 | * If we had an ILLEGAL REQUEST returned, then we may | |
1047 | * have performed an unsupported command. The only | |
1048 | * thing this should be would be a ten byte read where | |
1049 | * only a six byte read was supported. Also, on a | |
1050 | * system where READ CAPACITY failed, we may have read | |
1051 | * past the end of the disk. | |
1052 | */ | |
26a68019 JA |
1053 | if ((cmd->device->use_10_for_rw && |
1054 | sshdr.asc == 0x20 && sshdr.ascq == 0x00) && | |
1da177e4 LT |
1055 | (cmd->cmnd[0] == READ_10 || |
1056 | cmd->cmnd[0] == WRITE_10)) { | |
1057 | cmd->device->use_10_for_rw = 0; | |
1058 | /* | |
1059 | * This will cause a retry with a 6-byte | |
1060 | * command. | |
1061 | */ | |
1062 | scsi_requeue_command(q, cmd); | |
1063 | result = 0; | |
1064 | } else { | |
e91442b6 | 1065 | scsi_end_request(cmd, 0, this_count, 1); |
1da177e4 LT |
1066 | return; |
1067 | } | |
1068 | break; | |
1069 | case NOT_READY: | |
1070 | /* | |
1071 | * If the device is in the process of becoming ready, | |
1072 | * retry. | |
1073 | */ | |
1074 | if (sshdr.asc == 0x04 && sshdr.ascq == 0x01) { | |
1075 | scsi_requeue_command(q, cmd); | |
1076 | return; | |
1077 | } | |
3173d8c3 | 1078 | if (!(req->flags & REQ_QUIET)) |
3bf743e7 JG |
1079 | scmd_printk(KERN_INFO, cmd, |
1080 | "Device not ready.\n"); | |
e91442b6 | 1081 | scsi_end_request(cmd, 0, this_count, 1); |
1da177e4 LT |
1082 | return; |
1083 | case VOLUME_OVERFLOW: | |
3173d8c3 | 1084 | if (!(req->flags & REQ_QUIET)) { |
3bf743e7 JG |
1085 | scmd_printk(KERN_INFO, cmd, |
1086 | "Volume overflow, CDB: "); | |
3173d8c3 JB |
1087 | __scsi_print_command(cmd->data_cmnd); |
1088 | scsi_print_sense("", cmd); | |
1089 | } | |
e91442b6 | 1090 | scsi_end_request(cmd, 0, block_bytes, 1); |
1da177e4 LT |
1091 | return; |
1092 | default: | |
1093 | break; | |
1094 | } | |
1095 | } /* driver byte != 0 */ | |
1096 | if (host_byte(result) == DID_RESET) { | |
1097 | /* | |
1098 | * Third party bus reset or reset for error | |
1099 | * recovery reasons. Just retry the request | |
1100 | * and see what happens. | |
1101 | */ | |
1102 | scsi_requeue_command(q, cmd); | |
1103 | return; | |
1104 | } | |
1105 | if (result) { | |
3173d8c3 | 1106 | if (!(req->flags & REQ_QUIET)) { |
3bf743e7 JG |
1107 | scmd_printk(KERN_INFO, cmd, |
1108 | "SCSI error: return code = 0x%x\n", result); | |
3173d8c3 JB |
1109 | |
1110 | if (driver_byte(result) & DRIVER_SENSE) | |
1111 | scsi_print_sense("", cmd); | |
1112 | } | |
1da177e4 LT |
1113 | /* |
1114 | * Mark a single buffer as not uptodate. Queue the remainder. | |
1115 | * We sometimes get this cruft in the event that a medium error | |
1116 | * isn't properly reported. | |
1117 | */ | |
1118 | block_bytes = req->hard_cur_sectors << 9; | |
1119 | if (!block_bytes) | |
1120 | block_bytes = req->data_len; | |
e91442b6 | 1121 | scsi_end_request(cmd, 0, block_bytes, 1); |
1da177e4 LT |
1122 | } |
1123 | } | |
1124 | EXPORT_SYMBOL(scsi_io_completion); | |
1125 | ||
1126 | /* | |
1127 | * Function: scsi_init_io() | |
1128 | * | |
1129 | * Purpose: SCSI I/O initialize function. | |
1130 | * | |
1131 | * Arguments: cmd - Command descriptor we wish to initialize | |
1132 | * | |
1133 | * Returns: 0 on success | |
1134 | * BLKPREP_DEFER if the failure is retryable | |
1135 | * BLKPREP_KILL if the failure is fatal | |
1136 | */ | |
1137 | static int scsi_init_io(struct scsi_cmnd *cmd) | |
1138 | { | |
1139 | struct request *req = cmd->request; | |
1140 | struct scatterlist *sgpnt; | |
1141 | int count; | |
1142 | ||
1143 | /* | |
1144 | * if this is a rq->data based REQ_BLOCK_PC, setup for a non-sg xfer | |
1145 | */ | |
1146 | if ((req->flags & REQ_BLOCK_PC) && !req->bio) { | |
1147 | cmd->request_bufflen = req->data_len; | |
1148 | cmd->request_buffer = req->data; | |
1149 | req->buffer = req->data; | |
1150 | cmd->use_sg = 0; | |
1151 | return 0; | |
1152 | } | |
1153 | ||
1154 | /* | |
1155 | * we used to not use scatter-gather for single segment request, | |
1156 | * but now we do (it makes highmem I/O easier to support without | |
1157 | * kmapping pages) | |
1158 | */ | |
1159 | cmd->use_sg = req->nr_phys_segments; | |
1160 | ||
1161 | /* | |
1162 | * if sg table allocation fails, requeue request later. | |
1163 | */ | |
1164 | sgpnt = scsi_alloc_sgtable(cmd, GFP_ATOMIC); | |
7c72ce81 AS |
1165 | if (unlikely(!sgpnt)) { |
1166 | scsi_unprep_request(req); | |
1da177e4 | 1167 | return BLKPREP_DEFER; |
7c72ce81 | 1168 | } |
1da177e4 LT |
1169 | |
1170 | cmd->request_buffer = (char *) sgpnt; | |
1171 | cmd->request_bufflen = req->nr_sectors << 9; | |
1172 | if (blk_pc_request(req)) | |
1173 | cmd->request_bufflen = req->data_len; | |
1174 | req->buffer = NULL; | |
1175 | ||
1176 | /* | |
1177 | * Next, walk the list, and fill in the addresses and sizes of | |
1178 | * each segment. | |
1179 | */ | |
1180 | count = blk_rq_map_sg(req->q, req, cmd->request_buffer); | |
1181 | ||
1182 | /* | |
1183 | * mapped well, send it off | |
1184 | */ | |
1185 | if (likely(count <= cmd->use_sg)) { | |
1186 | cmd->use_sg = count; | |
1187 | return 0; | |
1188 | } | |
1189 | ||
1190 | printk(KERN_ERR "Incorrect number of segments after building list\n"); | |
1191 | printk(KERN_ERR "counted %d, received %d\n", count, cmd->use_sg); | |
1192 | printk(KERN_ERR "req nr_sec %lu, cur_nr_sec %u\n", req->nr_sectors, | |
1193 | req->current_nr_sectors); | |
1194 | ||
1195 | /* release the command and kill it */ | |
1196 | scsi_release_buffers(cmd); | |
1197 | scsi_put_command(cmd); | |
1198 | return BLKPREP_KILL; | |
1199 | } | |
1200 | ||
1da177e4 LT |
1201 | static int scsi_issue_flush_fn(request_queue_t *q, struct gendisk *disk, |
1202 | sector_t *error_sector) | |
1203 | { | |
1204 | struct scsi_device *sdev = q->queuedata; | |
1205 | struct scsi_driver *drv; | |
1206 | ||
1207 | if (sdev->sdev_state != SDEV_RUNNING) | |
1208 | return -ENXIO; | |
1209 | ||
1210 | drv = *(struct scsi_driver **) disk->private_data; | |
1211 | if (drv->issue_flush) | |
1212 | return drv->issue_flush(&sdev->sdev_gendev, error_sector); | |
1213 | ||
1214 | return -EOPNOTSUPP; | |
1215 | } | |
1216 | ||
776b23a0 | 1217 | static void scsi_blk_pc_done(struct scsi_cmnd *cmd) |
e537a36d JB |
1218 | { |
1219 | BUG_ON(!blk_pc_request(cmd->request)); | |
0d95716d MC |
1220 | /* |
1221 | * This will complete the whole command with uptodate=1 so | |
1222 | * as far as the block layer is concerned the command completed | |
1223 | * successfully. Since this is a REQ_BLOCK_PC command the | |
1224 | * caller should check the request's errors value | |
1225 | */ | |
1226 | scsi_io_completion(cmd, cmd->bufflen, 0); | |
e537a36d JB |
1227 | } |
1228 | ||
776b23a0 | 1229 | static void scsi_setup_blk_pc_cmnd(struct scsi_cmnd *cmd) |
7b16318d JB |
1230 | { |
1231 | struct request *req = cmd->request; | |
1232 | ||
1233 | BUG_ON(sizeof(req->cmd) > sizeof(cmd->cmnd)); | |
1234 | memcpy(cmd->cmnd, req->cmd, sizeof(cmd->cmnd)); | |
1235 | cmd->cmd_len = req->cmd_len; | |
1236 | if (!req->data_len) | |
1237 | cmd->sc_data_direction = DMA_NONE; | |
1238 | else if (rq_data_dir(req) == WRITE) | |
1239 | cmd->sc_data_direction = DMA_TO_DEVICE; | |
1240 | else | |
1241 | cmd->sc_data_direction = DMA_FROM_DEVICE; | |
1242 | ||
1243 | cmd->transfersize = req->data_len; | |
1244 | cmd->allowed = req->retries; | |
1245 | cmd->timeout_per_command = req->timeout; | |
776b23a0 | 1246 | cmd->done = scsi_blk_pc_done; |
7b16318d | 1247 | } |
7b16318d | 1248 | |
1da177e4 LT |
1249 | static int scsi_prep_fn(struct request_queue *q, struct request *req) |
1250 | { | |
1251 | struct scsi_device *sdev = q->queuedata; | |
1252 | struct scsi_cmnd *cmd; | |
1253 | int specials_only = 0; | |
1254 | ||
1255 | /* | |
1256 | * Just check to see if the device is online. If it isn't, we | |
1257 | * refuse to process any commands. The device must be brought | |
1258 | * online before trying any recovery commands | |
1259 | */ | |
1260 | if (unlikely(!scsi_device_online(sdev))) { | |
9ccfc756 JB |
1261 | sdev_printk(KERN_ERR, sdev, |
1262 | "rejecting I/O to offline device\n"); | |
6f16b535 | 1263 | goto kill; |
1da177e4 LT |
1264 | } |
1265 | if (unlikely(sdev->sdev_state != SDEV_RUNNING)) { | |
1266 | /* OK, we're not in a running state don't prep | |
1267 | * user commands */ | |
1268 | if (sdev->sdev_state == SDEV_DEL) { | |
1269 | /* Device is fully deleted, no commands | |
1270 | * at all allowed down */ | |
9ccfc756 JB |
1271 | sdev_printk(KERN_ERR, sdev, |
1272 | "rejecting I/O to dead device\n"); | |
6f16b535 | 1273 | goto kill; |
1da177e4 LT |
1274 | } |
1275 | /* OK, we only allow special commands (i.e. not | |
1276 | * user initiated ones */ | |
1277 | specials_only = sdev->sdev_state; | |
1278 | } | |
1279 | ||
1280 | /* | |
1281 | * Find the actual device driver associated with this command. | |
1282 | * The SPECIAL requests are things like character device or | |
1283 | * ioctls, which did not originate from ll_rw_blk. Note that | |
1284 | * the special field is also used to indicate the cmd for | |
1285 | * the remainder of a partially fulfilled request that can | |
1286 | * come up when there is a medium error. We have to treat | |
1287 | * these two cases differently. We differentiate by looking | |
1288 | * at request->cmd, as this tells us the real story. | |
1289 | */ | |
e537a36d | 1290 | if (req->flags & REQ_SPECIAL && req->special) { |
1da177e4 LT |
1291 | struct scsi_request *sreq = req->special; |
1292 | ||
1293 | if (sreq->sr_magic == SCSI_REQ_MAGIC) { | |
1294 | cmd = scsi_get_command(sreq->sr_device, GFP_ATOMIC); | |
1295 | if (unlikely(!cmd)) | |
1296 | goto defer; | |
1297 | scsi_init_cmd_from_req(cmd, sreq); | |
1298 | } else | |
1299 | cmd = req->special; | |
1300 | } else if (req->flags & (REQ_CMD | REQ_BLOCK_PC)) { | |
1301 | ||
e537a36d | 1302 | if(unlikely(specials_only) && !(req->flags & REQ_SPECIAL)) { |
1da177e4 LT |
1303 | if(specials_only == SDEV_QUIESCE || |
1304 | specials_only == SDEV_BLOCK) | |
6f16b535 | 1305 | goto defer; |
1da177e4 | 1306 | |
9ccfc756 JB |
1307 | sdev_printk(KERN_ERR, sdev, |
1308 | "rejecting I/O to device being removed\n"); | |
6f16b535 | 1309 | goto kill; |
1da177e4 LT |
1310 | } |
1311 | ||
1312 | ||
1313 | /* | |
1314 | * Now try and find a command block that we can use. | |
1315 | */ | |
1316 | if (!req->special) { | |
1317 | cmd = scsi_get_command(sdev, GFP_ATOMIC); | |
1318 | if (unlikely(!cmd)) | |
1319 | goto defer; | |
1320 | } else | |
1321 | cmd = req->special; | |
1322 | ||
1323 | /* pull a tag out of the request if we have one */ | |
1324 | cmd->tag = req->tag; | |
1325 | } else { | |
1326 | blk_dump_rq_flags(req, "SCSI bad req"); | |
6f16b535 | 1327 | goto kill; |
1da177e4 LT |
1328 | } |
1329 | ||
1330 | /* note the overloading of req->special. When the tag | |
1331 | * is active it always means cmd. If the tag goes | |
1332 | * back for re-queueing, it may be reset */ | |
1333 | req->special = cmd; | |
1334 | cmd->request = req; | |
1335 | ||
1336 | /* | |
1337 | * FIXME: drop the lock here because the functions below | |
1338 | * expect to be called without the queue lock held. Also, | |
1339 | * previously, we dequeued the request before dropping the | |
1340 | * lock. We hope REQ_STARTED prevents anything untoward from | |
1341 | * happening now. | |
1342 | */ | |
1343 | if (req->flags & (REQ_CMD | REQ_BLOCK_PC)) { | |
1da177e4 LT |
1344 | int ret; |
1345 | ||
1346 | /* | |
1347 | * This will do a couple of things: | |
1348 | * 1) Fill in the actual SCSI command. | |
1349 | * 2) Fill in any other upper-level specific fields | |
1350 | * (timeout). | |
1351 | * | |
1352 | * If this returns 0, it means that the request failed | |
1353 | * (reading past end of disk, reading offline device, | |
1354 | * etc). This won't actually talk to the device, but | |
1355 | * some kinds of consistency checking may cause the | |
1356 | * request to be rejected immediately. | |
1357 | */ | |
1358 | ||
1359 | /* | |
1360 | * This sets up the scatter-gather table (allocating if | |
1361 | * required). | |
1362 | */ | |
1363 | ret = scsi_init_io(cmd); | |
6f16b535 | 1364 | switch(ret) { |
7c72ce81 | 1365 | /* For BLKPREP_KILL/DEFER the cmd was released */ |
6f16b535 | 1366 | case BLKPREP_KILL: |
6f16b535 MC |
1367 | goto kill; |
1368 | case BLKPREP_DEFER: | |
1369 | goto defer; | |
1370 | } | |
1da177e4 LT |
1371 | |
1372 | /* | |
1373 | * Initialize the actual SCSI command for this request. | |
1374 | */ | |
776b23a0 CH |
1375 | if (req->flags & REQ_BLOCK_PC) { |
1376 | scsi_setup_blk_pc_cmnd(cmd); | |
1377 | } else if (req->rq_disk) { | |
1378 | struct scsi_driver *drv; | |
1379 | ||
e537a36d JB |
1380 | drv = *(struct scsi_driver **)req->rq_disk->private_data; |
1381 | if (unlikely(!drv->init_command(cmd))) { | |
1382 | scsi_release_buffers(cmd); | |
1383 | scsi_put_command(cmd); | |
6f16b535 | 1384 | goto kill; |
e537a36d | 1385 | } |
1da177e4 LT |
1386 | } |
1387 | } | |
1388 | ||
1389 | /* | |
1390 | * The request is now prepped, no need to come back here | |
1391 | */ | |
1392 | req->flags |= REQ_DONTPREP; | |
1393 | return BLKPREP_OK; | |
1394 | ||
1395 | defer: | |
1396 | /* If we defer, the elv_next_request() returns NULL, but the | |
1397 | * queue must be restarted, so we plug here if no returning | |
1398 | * command will automatically do that. */ | |
1399 | if (sdev->device_busy == 0) | |
1400 | blk_plug_device(q); | |
1401 | return BLKPREP_DEFER; | |
6f16b535 MC |
1402 | kill: |
1403 | req->errors = DID_NO_CONNECT << 16; | |
1404 | return BLKPREP_KILL; | |
1da177e4 LT |
1405 | } |
1406 | ||
1407 | /* | |
1408 | * scsi_dev_queue_ready: if we can send requests to sdev, return 1 else | |
1409 | * return 0. | |
1410 | * | |
1411 | * Called with the queue_lock held. | |
1412 | */ | |
1413 | static inline int scsi_dev_queue_ready(struct request_queue *q, | |
1414 | struct scsi_device *sdev) | |
1415 | { | |
1416 | if (sdev->device_busy >= sdev->queue_depth) | |
1417 | return 0; | |
1418 | if (sdev->device_busy == 0 && sdev->device_blocked) { | |
1419 | /* | |
1420 | * unblock after device_blocked iterates to zero | |
1421 | */ | |
1422 | if (--sdev->device_blocked == 0) { | |
1423 | SCSI_LOG_MLQUEUE(3, | |
9ccfc756 JB |
1424 | sdev_printk(KERN_INFO, sdev, |
1425 | "unblocking device at zero depth\n")); | |
1da177e4 LT |
1426 | } else { |
1427 | blk_plug_device(q); | |
1428 | return 0; | |
1429 | } | |
1430 | } | |
1431 | if (sdev->device_blocked) | |
1432 | return 0; | |
1433 | ||
1434 | return 1; | |
1435 | } | |
1436 | ||
1437 | /* | |
1438 | * scsi_host_queue_ready: if we can send requests to shost, return 1 else | |
1439 | * return 0. We must end up running the queue again whenever 0 is | |
1440 | * returned, else IO can hang. | |
1441 | * | |
1442 | * Called with host_lock held. | |
1443 | */ | |
1444 | static inline int scsi_host_queue_ready(struct request_queue *q, | |
1445 | struct Scsi_Host *shost, | |
1446 | struct scsi_device *sdev) | |
1447 | { | |
939647ee | 1448 | if (scsi_host_in_recovery(shost)) |
1da177e4 LT |
1449 | return 0; |
1450 | if (shost->host_busy == 0 && shost->host_blocked) { | |
1451 | /* | |
1452 | * unblock after host_blocked iterates to zero | |
1453 | */ | |
1454 | if (--shost->host_blocked == 0) { | |
1455 | SCSI_LOG_MLQUEUE(3, | |
1456 | printk("scsi%d unblocking host at zero depth\n", | |
1457 | shost->host_no)); | |
1458 | } else { | |
1459 | blk_plug_device(q); | |
1460 | return 0; | |
1461 | } | |
1462 | } | |
1463 | if ((shost->can_queue > 0 && shost->host_busy >= shost->can_queue) || | |
1464 | shost->host_blocked || shost->host_self_blocked) { | |
1465 | if (list_empty(&sdev->starved_entry)) | |
1466 | list_add_tail(&sdev->starved_entry, &shost->starved_list); | |
1467 | return 0; | |
1468 | } | |
1469 | ||
1470 | /* We're OK to process the command, so we can't be starved */ | |
1471 | if (!list_empty(&sdev->starved_entry)) | |
1472 | list_del_init(&sdev->starved_entry); | |
1473 | ||
1474 | return 1; | |
1475 | } | |
1476 | ||
1477 | /* | |
e91442b6 | 1478 | * Kill a request for a dead device |
1da177e4 | 1479 | */ |
e91442b6 | 1480 | static void scsi_kill_request(struct request *req, request_queue_t *q) |
1da177e4 | 1481 | { |
e91442b6 | 1482 | struct scsi_cmnd *cmd = req->special; |
1da177e4 | 1483 | |
788ce43a JB |
1484 | blkdev_dequeue_request(req); |
1485 | ||
e91442b6 JB |
1486 | if (unlikely(cmd == NULL)) { |
1487 | printk(KERN_CRIT "impossible request in %s.\n", | |
1488 | __FUNCTION__); | |
1489 | BUG(); | |
1da177e4 | 1490 | } |
e91442b6 JB |
1491 | |
1492 | scsi_init_cmd_errh(cmd); | |
1493 | cmd->result = DID_NO_CONNECT << 16; | |
1494 | atomic_inc(&cmd->device->iorequest_cnt); | |
1495 | __scsi_done(cmd); | |
1da177e4 LT |
1496 | } |
1497 | ||
1aea6434 JA |
1498 | static void scsi_softirq_done(struct request *rq) |
1499 | { | |
1500 | struct scsi_cmnd *cmd = rq->completion_data; | |
1501 | unsigned long wait_for = cmd->allowed * cmd->timeout_per_command; | |
1502 | int disposition; | |
1503 | ||
1504 | INIT_LIST_HEAD(&cmd->eh_entry); | |
1505 | ||
1506 | disposition = scsi_decide_disposition(cmd); | |
1507 | if (disposition != SUCCESS && | |
1508 | time_before(cmd->jiffies_at_alloc + wait_for, jiffies)) { | |
1509 | sdev_printk(KERN_ERR, cmd->device, | |
1510 | "timing out command, waited %lus\n", | |
1511 | wait_for/HZ); | |
1512 | disposition = SUCCESS; | |
1513 | } | |
1514 | ||
1515 | scsi_log_completion(cmd, disposition); | |
1516 | ||
1517 | switch (disposition) { | |
1518 | case SUCCESS: | |
1519 | scsi_finish_command(cmd); | |
1520 | break; | |
1521 | case NEEDS_RETRY: | |
1522 | scsi_retry_command(cmd); | |
1523 | break; | |
1524 | case ADD_TO_MLQUEUE: | |
1525 | scsi_queue_insert(cmd, SCSI_MLQUEUE_DEVICE_BUSY); | |
1526 | break; | |
1527 | default: | |
1528 | if (!scsi_eh_scmd_add(cmd, 0)) | |
1529 | scsi_finish_command(cmd); | |
1530 | } | |
1531 | } | |
1532 | ||
1da177e4 LT |
1533 | /* |
1534 | * Function: scsi_request_fn() | |
1535 | * | |
1536 | * Purpose: Main strategy routine for SCSI. | |
1537 | * | |
1538 | * Arguments: q - Pointer to actual queue. | |
1539 | * | |
1540 | * Returns: Nothing | |
1541 | * | |
1542 | * Lock status: IO request lock assumed to be held when called. | |
1543 | */ | |
1544 | static void scsi_request_fn(struct request_queue *q) | |
1545 | { | |
1546 | struct scsi_device *sdev = q->queuedata; | |
1547 | struct Scsi_Host *shost; | |
1548 | struct scsi_cmnd *cmd; | |
1549 | struct request *req; | |
1550 | ||
1551 | if (!sdev) { | |
1552 | printk("scsi: killing requests for dead queue\n"); | |
e91442b6 JB |
1553 | while ((req = elv_next_request(q)) != NULL) |
1554 | scsi_kill_request(req, q); | |
1da177e4 LT |
1555 | return; |
1556 | } | |
1557 | ||
1558 | if(!get_device(&sdev->sdev_gendev)) | |
1559 | /* We must be tearing the block queue down already */ | |
1560 | return; | |
1561 | ||
1562 | /* | |
1563 | * To start with, we keep looping until the queue is empty, or until | |
1564 | * the host is no longer able to accept any more requests. | |
1565 | */ | |
1566 | shost = sdev->host; | |
1567 | while (!blk_queue_plugged(q)) { | |
1568 | int rtn; | |
1569 | /* | |
1570 | * get next queueable request. We do this early to make sure | |
1571 | * that the request is fully prepared even if we cannot | |
1572 | * accept it. | |
1573 | */ | |
1574 | req = elv_next_request(q); | |
1575 | if (!req || !scsi_dev_queue_ready(q, sdev)) | |
1576 | break; | |
1577 | ||
1578 | if (unlikely(!scsi_device_online(sdev))) { | |
9ccfc756 JB |
1579 | sdev_printk(KERN_ERR, sdev, |
1580 | "rejecting I/O to offline device\n"); | |
e91442b6 | 1581 | scsi_kill_request(req, q); |
1da177e4 LT |
1582 | continue; |
1583 | } | |
1584 | ||
1585 | ||
1586 | /* | |
1587 | * Remove the request from the request list. | |
1588 | */ | |
1589 | if (!(blk_queue_tagged(q) && !blk_queue_start_tag(q, req))) | |
1590 | blkdev_dequeue_request(req); | |
1591 | sdev->device_busy++; | |
1592 | ||
1593 | spin_unlock(q->queue_lock); | |
e91442b6 JB |
1594 | cmd = req->special; |
1595 | if (unlikely(cmd == NULL)) { | |
1596 | printk(KERN_CRIT "impossible request in %s.\n" | |
1597 | "please mail a stack trace to " | |
1598 | "linux-scsi@vger.kernel.org", | |
1599 | __FUNCTION__); | |
1600 | BUG(); | |
1601 | } | |
1da177e4 LT |
1602 | spin_lock(shost->host_lock); |
1603 | ||
1604 | if (!scsi_host_queue_ready(q, shost, sdev)) | |
1605 | goto not_ready; | |
1606 | if (sdev->single_lun) { | |
1607 | if (scsi_target(sdev)->starget_sdev_user && | |
1608 | scsi_target(sdev)->starget_sdev_user != sdev) | |
1609 | goto not_ready; | |
1610 | scsi_target(sdev)->starget_sdev_user = sdev; | |
1611 | } | |
1612 | shost->host_busy++; | |
1613 | ||
1614 | /* | |
1615 | * XXX(hch): This is rather suboptimal, scsi_dispatch_cmd will | |
1616 | * take the lock again. | |
1617 | */ | |
1618 | spin_unlock_irq(shost->host_lock); | |
1619 | ||
1da177e4 LT |
1620 | /* |
1621 | * Finally, initialize any error handling parameters, and set up | |
1622 | * the timers for timeouts. | |
1623 | */ | |
1624 | scsi_init_cmd_errh(cmd); | |
1625 | ||
1626 | /* | |
1627 | * Dispatch the command to the low-level driver. | |
1628 | */ | |
1629 | rtn = scsi_dispatch_cmd(cmd); | |
1630 | spin_lock_irq(q->queue_lock); | |
1631 | if(rtn) { | |
1632 | /* we're refusing the command; because of | |
1633 | * the way locks get dropped, we need to | |
1634 | * check here if plugging is required */ | |
1635 | if(sdev->device_busy == 0) | |
1636 | blk_plug_device(q); | |
1637 | ||
1638 | break; | |
1639 | } | |
1640 | } | |
1641 | ||
1642 | goto out; | |
1643 | ||
1644 | not_ready: | |
1645 | spin_unlock_irq(shost->host_lock); | |
1646 | ||
1647 | /* | |
1648 | * lock q, handle tag, requeue req, and decrement device_busy. We | |
1649 | * must return with queue_lock held. | |
1650 | * | |
1651 | * Decrementing device_busy without checking it is OK, as all such | |
1652 | * cases (host limits or settings) should run the queue at some | |
1653 | * later time. | |
1654 | */ | |
1655 | spin_lock_irq(q->queue_lock); | |
1656 | blk_requeue_request(q, req); | |
1657 | sdev->device_busy--; | |
1658 | if(sdev->device_busy == 0) | |
1659 | blk_plug_device(q); | |
1660 | out: | |
1661 | /* must be careful here...if we trigger the ->remove() function | |
1662 | * we cannot be holding the q lock */ | |
1663 | spin_unlock_irq(q->queue_lock); | |
1664 | put_device(&sdev->sdev_gendev); | |
1665 | spin_lock_irq(q->queue_lock); | |
1666 | } | |
1667 | ||
1668 | u64 scsi_calculate_bounce_limit(struct Scsi_Host *shost) | |
1669 | { | |
1670 | struct device *host_dev; | |
1671 | u64 bounce_limit = 0xffffffff; | |
1672 | ||
1673 | if (shost->unchecked_isa_dma) | |
1674 | return BLK_BOUNCE_ISA; | |
1675 | /* | |
1676 | * Platforms with virtual-DMA translation | |
1677 | * hardware have no practical limit. | |
1678 | */ | |
1679 | if (!PCI_DMA_BUS_IS_PHYS) | |
1680 | return BLK_BOUNCE_ANY; | |
1681 | ||
1682 | host_dev = scsi_get_device(shost); | |
1683 | if (host_dev && host_dev->dma_mask) | |
1684 | bounce_limit = *host_dev->dma_mask; | |
1685 | ||
1686 | return bounce_limit; | |
1687 | } | |
1688 | EXPORT_SYMBOL(scsi_calculate_bounce_limit); | |
1689 | ||
1690 | struct request_queue *scsi_alloc_queue(struct scsi_device *sdev) | |
1691 | { | |
1692 | struct Scsi_Host *shost = sdev->host; | |
1693 | struct request_queue *q; | |
1694 | ||
152587de | 1695 | q = blk_init_queue(scsi_request_fn, NULL); |
1da177e4 LT |
1696 | if (!q) |
1697 | return NULL; | |
1698 | ||
1699 | blk_queue_prep_rq(q, scsi_prep_fn); | |
1700 | ||
1701 | blk_queue_max_hw_segments(q, shost->sg_tablesize); | |
1702 | blk_queue_max_phys_segments(q, SCSI_MAX_PHYS_SEGMENTS); | |
1703 | blk_queue_max_sectors(q, shost->max_sectors); | |
1704 | blk_queue_bounce_limit(q, scsi_calculate_bounce_limit(shost)); | |
1705 | blk_queue_segment_boundary(q, shost->dma_boundary); | |
1706 | blk_queue_issue_flush_fn(q, scsi_issue_flush_fn); | |
1aea6434 | 1707 | blk_queue_softirq_done(q, scsi_softirq_done); |
1da177e4 | 1708 | |
1da177e4 LT |
1709 | if (!shost->use_clustering) |
1710 | clear_bit(QUEUE_FLAG_CLUSTER, &q->queue_flags); | |
1711 | return q; | |
1712 | } | |
1713 | ||
1714 | void scsi_free_queue(struct request_queue *q) | |
1715 | { | |
1716 | blk_cleanup_queue(q); | |
1717 | } | |
1718 | ||
1719 | /* | |
1720 | * Function: scsi_block_requests() | |
1721 | * | |
1722 | * Purpose: Utility function used by low-level drivers to prevent further | |
1723 | * commands from being queued to the device. | |
1724 | * | |
1725 | * Arguments: shost - Host in question | |
1726 | * | |
1727 | * Returns: Nothing | |
1728 | * | |
1729 | * Lock status: No locks are assumed held. | |
1730 | * | |
1731 | * Notes: There is no timer nor any other means by which the requests | |
1732 | * get unblocked other than the low-level driver calling | |
1733 | * scsi_unblock_requests(). | |
1734 | */ | |
1735 | void scsi_block_requests(struct Scsi_Host *shost) | |
1736 | { | |
1737 | shost->host_self_blocked = 1; | |
1738 | } | |
1739 | EXPORT_SYMBOL(scsi_block_requests); | |
1740 | ||
1741 | /* | |
1742 | * Function: scsi_unblock_requests() | |
1743 | * | |
1744 | * Purpose: Utility function used by low-level drivers to allow further | |
1745 | * commands from being queued to the device. | |
1746 | * | |
1747 | * Arguments: shost - Host in question | |
1748 | * | |
1749 | * Returns: Nothing | |
1750 | * | |
1751 | * Lock status: No locks are assumed held. | |
1752 | * | |
1753 | * Notes: There is no timer nor any other means by which the requests | |
1754 | * get unblocked other than the low-level driver calling | |
1755 | * scsi_unblock_requests(). | |
1756 | * | |
1757 | * This is done as an API function so that changes to the | |
1758 | * internals of the scsi mid-layer won't require wholesale | |
1759 | * changes to drivers that use this feature. | |
1760 | */ | |
1761 | void scsi_unblock_requests(struct Scsi_Host *shost) | |
1762 | { | |
1763 | shost->host_self_blocked = 0; | |
1764 | scsi_run_host_queues(shost); | |
1765 | } | |
1766 | EXPORT_SYMBOL(scsi_unblock_requests); | |
1767 | ||
1768 | int __init scsi_init_queue(void) | |
1769 | { | |
1770 | int i; | |
1771 | ||
aa7b5cd7 MC |
1772 | scsi_io_context_cache = kmem_cache_create("scsi_io_context", |
1773 | sizeof(struct scsi_io_context), | |
1774 | 0, 0, NULL, NULL); | |
1775 | if (!scsi_io_context_cache) { | |
1776 | printk(KERN_ERR "SCSI: can't init scsi io context cache\n"); | |
1777 | return -ENOMEM; | |
1778 | } | |
1779 | ||
1da177e4 LT |
1780 | for (i = 0; i < SG_MEMPOOL_NR; i++) { |
1781 | struct scsi_host_sg_pool *sgp = scsi_sg_pools + i; | |
1782 | int size = sgp->size * sizeof(struct scatterlist); | |
1783 | ||
1784 | sgp->slab = kmem_cache_create(sgp->name, size, 0, | |
1785 | SLAB_HWCACHE_ALIGN, NULL, NULL); | |
1786 | if (!sgp->slab) { | |
1787 | printk(KERN_ERR "SCSI: can't init sg slab %s\n", | |
1788 | sgp->name); | |
1789 | } | |
1790 | ||
1791 | sgp->pool = mempool_create(SG_MEMPOOL_SIZE, | |
1792 | mempool_alloc_slab, mempool_free_slab, | |
1793 | sgp->slab); | |
1794 | if (!sgp->pool) { | |
1795 | printk(KERN_ERR "SCSI: can't init sg mempool %s\n", | |
1796 | sgp->name); | |
1797 | } | |
1798 | } | |
1799 | ||
1800 | return 0; | |
1801 | } | |
1802 | ||
1803 | void scsi_exit_queue(void) | |
1804 | { | |
1805 | int i; | |
1806 | ||
aa7b5cd7 MC |
1807 | kmem_cache_destroy(scsi_io_context_cache); |
1808 | ||
1da177e4 LT |
1809 | for (i = 0; i < SG_MEMPOOL_NR; i++) { |
1810 | struct scsi_host_sg_pool *sgp = scsi_sg_pools + i; | |
1811 | mempool_destroy(sgp->pool); | |
1812 | kmem_cache_destroy(sgp->slab); | |
1813 | } | |
1814 | } | |
1815 | /** | |
ea73a9f2 | 1816 | * scsi_mode_sense - issue a mode sense, falling back from 10 to |
1da177e4 | 1817 | * six bytes if necessary. |
1cf72699 | 1818 | * @sdev: SCSI device to be queried |
1da177e4 LT |
1819 | * @dbd: set if mode sense will allow block descriptors to be returned |
1820 | * @modepage: mode page being requested | |
1821 | * @buffer: request buffer (may not be smaller than eight bytes) | |
1822 | * @len: length of request buffer. | |
1823 | * @timeout: command timeout | |
1824 | * @retries: number of retries before failing | |
1825 | * @data: returns a structure abstracting the mode header data | |
1cf72699 JB |
1826 | * @sense: place to put sense data (or NULL if no sense to be collected). |
1827 | * must be SCSI_SENSE_BUFFERSIZE big. | |
1da177e4 LT |
1828 | * |
1829 | * Returns zero if unsuccessful, or the header offset (either 4 | |
1830 | * or 8 depending on whether a six or ten byte command was | |
1831 | * issued) if successful. | |
1832 | **/ | |
1833 | int | |
1cf72699 | 1834 | scsi_mode_sense(struct scsi_device *sdev, int dbd, int modepage, |
1da177e4 | 1835 | unsigned char *buffer, int len, int timeout, int retries, |
ea73a9f2 | 1836 | struct scsi_mode_data *data, struct scsi_sense_hdr *sshdr) { |
1da177e4 LT |
1837 | unsigned char cmd[12]; |
1838 | int use_10_for_ms; | |
1839 | int header_length; | |
1cf72699 | 1840 | int result; |
ea73a9f2 | 1841 | struct scsi_sense_hdr my_sshdr; |
1da177e4 LT |
1842 | |
1843 | memset(data, 0, sizeof(*data)); | |
1844 | memset(&cmd[0], 0, 12); | |
1845 | cmd[1] = dbd & 0x18; /* allows DBD and LLBA bits */ | |
1846 | cmd[2] = modepage; | |
1847 | ||
ea73a9f2 JB |
1848 | /* caller might not be interested in sense, but we need it */ |
1849 | if (!sshdr) | |
1850 | sshdr = &my_sshdr; | |
1851 | ||
1da177e4 | 1852 | retry: |
1cf72699 | 1853 | use_10_for_ms = sdev->use_10_for_ms; |
1da177e4 LT |
1854 | |
1855 | if (use_10_for_ms) { | |
1856 | if (len < 8) | |
1857 | len = 8; | |
1858 | ||
1859 | cmd[0] = MODE_SENSE_10; | |
1860 | cmd[8] = len; | |
1861 | header_length = 8; | |
1862 | } else { | |
1863 | if (len < 4) | |
1864 | len = 4; | |
1865 | ||
1866 | cmd[0] = MODE_SENSE; | |
1867 | cmd[4] = len; | |
1868 | header_length = 4; | |
1869 | } | |
1870 | ||
1da177e4 LT |
1871 | memset(buffer, 0, len); |
1872 | ||
1cf72699 | 1873 | result = scsi_execute_req(sdev, cmd, DMA_FROM_DEVICE, buffer, len, |
ea73a9f2 | 1874 | sshdr, timeout, retries); |
1da177e4 LT |
1875 | |
1876 | /* This code looks awful: what it's doing is making sure an | |
1877 | * ILLEGAL REQUEST sense return identifies the actual command | |
1878 | * byte as the problem. MODE_SENSE commands can return | |
1879 | * ILLEGAL REQUEST if the code page isn't supported */ | |
1880 | ||
1cf72699 JB |
1881 | if (use_10_for_ms && !scsi_status_is_good(result) && |
1882 | (driver_byte(result) & DRIVER_SENSE)) { | |
ea73a9f2 JB |
1883 | if (scsi_sense_valid(sshdr)) { |
1884 | if ((sshdr->sense_key == ILLEGAL_REQUEST) && | |
1885 | (sshdr->asc == 0x20) && (sshdr->ascq == 0)) { | |
1da177e4 LT |
1886 | /* |
1887 | * Invalid command operation code | |
1888 | */ | |
1cf72699 | 1889 | sdev->use_10_for_ms = 0; |
1da177e4 LT |
1890 | goto retry; |
1891 | } | |
1892 | } | |
1893 | } | |
1894 | ||
1cf72699 | 1895 | if(scsi_status_is_good(result)) { |
1da177e4 LT |
1896 | data->header_length = header_length; |
1897 | if(use_10_for_ms) { | |
1898 | data->length = buffer[0]*256 + buffer[1] + 2; | |
1899 | data->medium_type = buffer[2]; | |
1900 | data->device_specific = buffer[3]; | |
1901 | data->longlba = buffer[4] & 0x01; | |
1902 | data->block_descriptor_length = buffer[6]*256 | |
1903 | + buffer[7]; | |
1904 | } else { | |
1905 | data->length = buffer[0] + 1; | |
1906 | data->medium_type = buffer[1]; | |
1907 | data->device_specific = buffer[2]; | |
1908 | data->block_descriptor_length = buffer[3]; | |
1909 | } | |
1910 | } | |
1911 | ||
1cf72699 | 1912 | return result; |
1da177e4 LT |
1913 | } |
1914 | EXPORT_SYMBOL(scsi_mode_sense); | |
1915 | ||
1916 | int | |
1917 | scsi_test_unit_ready(struct scsi_device *sdev, int timeout, int retries) | |
1918 | { | |
1da177e4 LT |
1919 | char cmd[] = { |
1920 | TEST_UNIT_READY, 0, 0, 0, 0, 0, | |
1921 | }; | |
ea73a9f2 | 1922 | struct scsi_sense_hdr sshdr; |
1da177e4 LT |
1923 | int result; |
1924 | ||
ea73a9f2 | 1925 | result = scsi_execute_req(sdev, cmd, DMA_NONE, NULL, 0, &sshdr, |
1cf72699 | 1926 | timeout, retries); |
1da177e4 | 1927 | |
1cf72699 | 1928 | if ((driver_byte(result) & DRIVER_SENSE) && sdev->removable) { |
1da177e4 | 1929 | |
ea73a9f2 | 1930 | if ((scsi_sense_valid(&sshdr)) && |
1da177e4 LT |
1931 | ((sshdr.sense_key == UNIT_ATTENTION) || |
1932 | (sshdr.sense_key == NOT_READY))) { | |
1933 | sdev->changed = 1; | |
1cf72699 | 1934 | result = 0; |
1da177e4 LT |
1935 | } |
1936 | } | |
1da177e4 LT |
1937 | return result; |
1938 | } | |
1939 | EXPORT_SYMBOL(scsi_test_unit_ready); | |
1940 | ||
1941 | /** | |
1942 | * scsi_device_set_state - Take the given device through the device | |
1943 | * state model. | |
1944 | * @sdev: scsi device to change the state of. | |
1945 | * @state: state to change to. | |
1946 | * | |
1947 | * Returns zero if unsuccessful or an error if the requested | |
1948 | * transition is illegal. | |
1949 | **/ | |
1950 | int | |
1951 | scsi_device_set_state(struct scsi_device *sdev, enum scsi_device_state state) | |
1952 | { | |
1953 | enum scsi_device_state oldstate = sdev->sdev_state; | |
1954 | ||
1955 | if (state == oldstate) | |
1956 | return 0; | |
1957 | ||
1958 | switch (state) { | |
1959 | case SDEV_CREATED: | |
1960 | /* There are no legal states that come back to | |
1961 | * created. This is the manually initialised start | |
1962 | * state */ | |
1963 | goto illegal; | |
1964 | ||
1965 | case SDEV_RUNNING: | |
1966 | switch (oldstate) { | |
1967 | case SDEV_CREATED: | |
1968 | case SDEV_OFFLINE: | |
1969 | case SDEV_QUIESCE: | |
1970 | case SDEV_BLOCK: | |
1971 | break; | |
1972 | default: | |
1973 | goto illegal; | |
1974 | } | |
1975 | break; | |
1976 | ||
1977 | case SDEV_QUIESCE: | |
1978 | switch (oldstate) { | |
1979 | case SDEV_RUNNING: | |
1980 | case SDEV_OFFLINE: | |
1981 | break; | |
1982 | default: | |
1983 | goto illegal; | |
1984 | } | |
1985 | break; | |
1986 | ||
1987 | case SDEV_OFFLINE: | |
1988 | switch (oldstate) { | |
1989 | case SDEV_CREATED: | |
1990 | case SDEV_RUNNING: | |
1991 | case SDEV_QUIESCE: | |
1992 | case SDEV_BLOCK: | |
1993 | break; | |
1994 | default: | |
1995 | goto illegal; | |
1996 | } | |
1997 | break; | |
1998 | ||
1999 | case SDEV_BLOCK: | |
2000 | switch (oldstate) { | |
2001 | case SDEV_CREATED: | |
2002 | case SDEV_RUNNING: | |
2003 | break; | |
2004 | default: | |
2005 | goto illegal; | |
2006 | } | |
2007 | break; | |
2008 | ||
2009 | case SDEV_CANCEL: | |
2010 | switch (oldstate) { | |
2011 | case SDEV_CREATED: | |
2012 | case SDEV_RUNNING: | |
2013 | case SDEV_OFFLINE: | |
2014 | case SDEV_BLOCK: | |
2015 | break; | |
2016 | default: | |
2017 | goto illegal; | |
2018 | } | |
2019 | break; | |
2020 | ||
2021 | case SDEV_DEL: | |
2022 | switch (oldstate) { | |
2023 | case SDEV_CANCEL: | |
2024 | break; | |
2025 | default: | |
2026 | goto illegal; | |
2027 | } | |
2028 | break; | |
2029 | ||
2030 | } | |
2031 | sdev->sdev_state = state; | |
2032 | return 0; | |
2033 | ||
2034 | illegal: | |
2035 | SCSI_LOG_ERROR_RECOVERY(1, | |
9ccfc756 JB |
2036 | sdev_printk(KERN_ERR, sdev, |
2037 | "Illegal state transition %s->%s\n", | |
2038 | scsi_device_state_name(oldstate), | |
2039 | scsi_device_state_name(state)) | |
1da177e4 LT |
2040 | ); |
2041 | return -EINVAL; | |
2042 | } | |
2043 | EXPORT_SYMBOL(scsi_device_set_state); | |
2044 | ||
2045 | /** | |
2046 | * scsi_device_quiesce - Block user issued commands. | |
2047 | * @sdev: scsi device to quiesce. | |
2048 | * | |
2049 | * This works by trying to transition to the SDEV_QUIESCE state | |
2050 | * (which must be a legal transition). When the device is in this | |
2051 | * state, only special requests will be accepted, all others will | |
2052 | * be deferred. Since special requests may also be requeued requests, | |
2053 | * a successful return doesn't guarantee the device will be | |
2054 | * totally quiescent. | |
2055 | * | |
2056 | * Must be called with user context, may sleep. | |
2057 | * | |
2058 | * Returns zero if unsuccessful or an error if not. | |
2059 | **/ | |
2060 | int | |
2061 | scsi_device_quiesce(struct scsi_device *sdev) | |
2062 | { | |
2063 | int err = scsi_device_set_state(sdev, SDEV_QUIESCE); | |
2064 | if (err) | |
2065 | return err; | |
2066 | ||
2067 | scsi_run_queue(sdev->request_queue); | |
2068 | while (sdev->device_busy) { | |
2069 | msleep_interruptible(200); | |
2070 | scsi_run_queue(sdev->request_queue); | |
2071 | } | |
2072 | return 0; | |
2073 | } | |
2074 | EXPORT_SYMBOL(scsi_device_quiesce); | |
2075 | ||
2076 | /** | |
2077 | * scsi_device_resume - Restart user issued commands to a quiesced device. | |
2078 | * @sdev: scsi device to resume. | |
2079 | * | |
2080 | * Moves the device from quiesced back to running and restarts the | |
2081 | * queues. | |
2082 | * | |
2083 | * Must be called with user context, may sleep. | |
2084 | **/ | |
2085 | void | |
2086 | scsi_device_resume(struct scsi_device *sdev) | |
2087 | { | |
2088 | if(scsi_device_set_state(sdev, SDEV_RUNNING)) | |
2089 | return; | |
2090 | scsi_run_queue(sdev->request_queue); | |
2091 | } | |
2092 | EXPORT_SYMBOL(scsi_device_resume); | |
2093 | ||
2094 | static void | |
2095 | device_quiesce_fn(struct scsi_device *sdev, void *data) | |
2096 | { | |
2097 | scsi_device_quiesce(sdev); | |
2098 | } | |
2099 | ||
2100 | void | |
2101 | scsi_target_quiesce(struct scsi_target *starget) | |
2102 | { | |
2103 | starget_for_each_device(starget, NULL, device_quiesce_fn); | |
2104 | } | |
2105 | EXPORT_SYMBOL(scsi_target_quiesce); | |
2106 | ||
2107 | static void | |
2108 | device_resume_fn(struct scsi_device *sdev, void *data) | |
2109 | { | |
2110 | scsi_device_resume(sdev); | |
2111 | } | |
2112 | ||
2113 | void | |
2114 | scsi_target_resume(struct scsi_target *starget) | |
2115 | { | |
2116 | starget_for_each_device(starget, NULL, device_resume_fn); | |
2117 | } | |
2118 | EXPORT_SYMBOL(scsi_target_resume); | |
2119 | ||
2120 | /** | |
2121 | * scsi_internal_device_block - internal function to put a device | |
2122 | * temporarily into the SDEV_BLOCK state | |
2123 | * @sdev: device to block | |
2124 | * | |
2125 | * Block request made by scsi lld's to temporarily stop all | |
2126 | * scsi commands on the specified device. Called from interrupt | |
2127 | * or normal process context. | |
2128 | * | |
2129 | * Returns zero if successful or error if not | |
2130 | * | |
2131 | * Notes: | |
2132 | * This routine transitions the device to the SDEV_BLOCK state | |
2133 | * (which must be a legal transition). When the device is in this | |
2134 | * state, all commands are deferred until the scsi lld reenables | |
2135 | * the device with scsi_device_unblock or device_block_tmo fires. | |
2136 | * This routine assumes the host_lock is held on entry. | |
2137 | **/ | |
2138 | int | |
2139 | scsi_internal_device_block(struct scsi_device *sdev) | |
2140 | { | |
2141 | request_queue_t *q = sdev->request_queue; | |
2142 | unsigned long flags; | |
2143 | int err = 0; | |
2144 | ||
2145 | err = scsi_device_set_state(sdev, SDEV_BLOCK); | |
2146 | if (err) | |
2147 | return err; | |
2148 | ||
2149 | /* | |
2150 | * The device has transitioned to SDEV_BLOCK. Stop the | |
2151 | * block layer from calling the midlayer with this device's | |
2152 | * request queue. | |
2153 | */ | |
2154 | spin_lock_irqsave(q->queue_lock, flags); | |
2155 | blk_stop_queue(q); | |
2156 | spin_unlock_irqrestore(q->queue_lock, flags); | |
2157 | ||
2158 | return 0; | |
2159 | } | |
2160 | EXPORT_SYMBOL_GPL(scsi_internal_device_block); | |
2161 | ||
2162 | /** | |
2163 | * scsi_internal_device_unblock - resume a device after a block request | |
2164 | * @sdev: device to resume | |
2165 | * | |
2166 | * Called by scsi lld's or the midlayer to restart the device queue | |
2167 | * for the previously suspended scsi device. Called from interrupt or | |
2168 | * normal process context. | |
2169 | * | |
2170 | * Returns zero if successful or error if not. | |
2171 | * | |
2172 | * Notes: | |
2173 | * This routine transitions the device to the SDEV_RUNNING state | |
2174 | * (which must be a legal transition) allowing the midlayer to | |
2175 | * goose the queue for this device. This routine assumes the | |
2176 | * host_lock is held upon entry. | |
2177 | **/ | |
2178 | int | |
2179 | scsi_internal_device_unblock(struct scsi_device *sdev) | |
2180 | { | |
2181 | request_queue_t *q = sdev->request_queue; | |
2182 | int err; | |
2183 | unsigned long flags; | |
2184 | ||
2185 | /* | |
2186 | * Try to transition the scsi device to SDEV_RUNNING | |
2187 | * and goose the device queue if successful. | |
2188 | */ | |
2189 | err = scsi_device_set_state(sdev, SDEV_RUNNING); | |
2190 | if (err) | |
2191 | return err; | |
2192 | ||
2193 | spin_lock_irqsave(q->queue_lock, flags); | |
2194 | blk_start_queue(q); | |
2195 | spin_unlock_irqrestore(q->queue_lock, flags); | |
2196 | ||
2197 | return 0; | |
2198 | } | |
2199 | EXPORT_SYMBOL_GPL(scsi_internal_device_unblock); | |
2200 | ||
2201 | static void | |
2202 | device_block(struct scsi_device *sdev, void *data) | |
2203 | { | |
2204 | scsi_internal_device_block(sdev); | |
2205 | } | |
2206 | ||
2207 | static int | |
2208 | target_block(struct device *dev, void *data) | |
2209 | { | |
2210 | if (scsi_is_target_device(dev)) | |
2211 | starget_for_each_device(to_scsi_target(dev), NULL, | |
2212 | device_block); | |
2213 | return 0; | |
2214 | } | |
2215 | ||
2216 | void | |
2217 | scsi_target_block(struct device *dev) | |
2218 | { | |
2219 | if (scsi_is_target_device(dev)) | |
2220 | starget_for_each_device(to_scsi_target(dev), NULL, | |
2221 | device_block); | |
2222 | else | |
2223 | device_for_each_child(dev, NULL, target_block); | |
2224 | } | |
2225 | EXPORT_SYMBOL_GPL(scsi_target_block); | |
2226 | ||
2227 | static void | |
2228 | device_unblock(struct scsi_device *sdev, void *data) | |
2229 | { | |
2230 | scsi_internal_device_unblock(sdev); | |
2231 | } | |
2232 | ||
2233 | static int | |
2234 | target_unblock(struct device *dev, void *data) | |
2235 | { | |
2236 | if (scsi_is_target_device(dev)) | |
2237 | starget_for_each_device(to_scsi_target(dev), NULL, | |
2238 | device_unblock); | |
2239 | return 0; | |
2240 | } | |
2241 | ||
2242 | void | |
2243 | scsi_target_unblock(struct device *dev) | |
2244 | { | |
2245 | if (scsi_is_target_device(dev)) | |
2246 | starget_for_each_device(to_scsi_target(dev), NULL, | |
2247 | device_unblock); | |
2248 | else | |
2249 | device_for_each_child(dev, NULL, target_unblock); | |
2250 | } | |
2251 | EXPORT_SYMBOL_GPL(scsi_target_unblock); | |
faead26d JB |
2252 | |
2253 | ||
2254 | struct work_queue_work { | |
2255 | struct work_struct work; | |
2256 | void (*fn)(void *); | |
2257 | void *data; | |
2258 | }; | |
2259 | ||
2260 | static void execute_in_process_context_work(void *data) | |
2261 | { | |
2262 | void (*fn)(void *data); | |
2263 | struct work_queue_work *wqw = data; | |
2264 | ||
2265 | fn = wqw->fn; | |
2266 | data = wqw->data; | |
2267 | ||
2268 | kfree(wqw); | |
2269 | ||
2270 | fn(data); | |
2271 | } | |
2272 | ||
2273 | /** | |
2274 | * scsi_execute_in_process_context - reliably execute the routine with user context | |
2275 | * @fn: the function to execute | |
2276 | * @data: data to pass to the function | |
2277 | * | |
2278 | * Executes the function immediately if process context is available, | |
2279 | * otherwise schedules the function for delayed execution. | |
2280 | * | |
2281 | * Returns: 0 - function was executed | |
2282 | * 1 - function was scheduled for execution | |
2283 | * <0 - error | |
2284 | */ | |
2285 | int scsi_execute_in_process_context(void (*fn)(void *data), void *data) | |
2286 | { | |
2287 | struct work_queue_work *wqw; | |
2288 | ||
2289 | if (!in_interrupt()) { | |
2290 | fn(data); | |
2291 | return 0; | |
2292 | } | |
2293 | ||
2294 | wqw = kmalloc(sizeof(struct work_queue_work), GFP_ATOMIC); | |
2295 | ||
2296 | if (unlikely(!wqw)) { | |
2297 | printk(KERN_ERR "Failed to allocate memory\n"); | |
2298 | WARN_ON(1); | |
2299 | return -ENOMEM; | |
2300 | } | |
2301 | ||
2302 | INIT_WORK(&wqw->work, execute_in_process_context_work, wqw); | |
2303 | wqw->fn = fn; | |
2304 | wqw->data = data; | |
2305 | schedule_work(&wqw->work); | |
2306 | ||
2307 | return 1; | |
2308 | } | |
2309 | EXPORT_SYMBOL_GPL(scsi_execute_in_process_context); |