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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> | |
beb40487 | 22 | #include <scsi/scsi_cmnd.h> |
1da177e4 LT |
23 | #include <scsi/scsi_dbg.h> |
24 | #include <scsi/scsi_device.h> | |
25 | #include <scsi/scsi_driver.h> | |
26 | #include <scsi/scsi_eh.h> | |
27 | #include <scsi/scsi_host.h> | |
1da177e4 LT |
28 | |
29 | #include "scsi_priv.h" | |
30 | #include "scsi_logging.h" | |
31 | ||
32 | ||
6391a113 | 33 | #define SG_MEMPOOL_NR ARRAY_SIZE(scsi_sg_pools) |
1da177e4 LT |
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; | |
beb40487 | 86 | req->special = NULL; |
e91442b6 | 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 | ||
39216033 | 164 | /** |
33aa687d | 165 | * scsi_execute - insert request and wait for the result |
39216033 JB |
166 | * @sdev: scsi device |
167 | * @cmd: scsi command | |
168 | * @data_direction: data direction | |
169 | * @buffer: data buffer | |
170 | * @bufflen: len of buffer | |
171 | * @sense: optional sense buffer | |
172 | * @timeout: request timeout in seconds | |
173 | * @retries: number of times to retry request | |
33aa687d | 174 | * @flags: or into request flags; |
39216033 | 175 | * |
ea73a9f2 JB |
176 | * returns the req->errors value which is the the scsi_cmnd result |
177 | * field. | |
39216033 | 178 | **/ |
33aa687d JB |
179 | int scsi_execute(struct scsi_device *sdev, const unsigned char *cmd, |
180 | int data_direction, void *buffer, unsigned bufflen, | |
181 | unsigned char *sense, int timeout, int retries, int flags) | |
39216033 JB |
182 | { |
183 | struct request *req; | |
184 | int write = (data_direction == DMA_TO_DEVICE); | |
185 | int ret = DRIVER_ERROR << 24; | |
186 | ||
187 | req = blk_get_request(sdev->request_queue, write, __GFP_WAIT); | |
188 | ||
189 | if (bufflen && blk_rq_map_kern(sdev->request_queue, req, | |
190 | buffer, bufflen, __GFP_WAIT)) | |
191 | goto out; | |
192 | ||
193 | req->cmd_len = COMMAND_SIZE(cmd[0]); | |
194 | memcpy(req->cmd, cmd, req->cmd_len); | |
195 | req->sense = sense; | |
196 | req->sense_len = 0; | |
17e01f21 | 197 | req->retries = retries; |
39216033 | 198 | req->timeout = timeout; |
3173d8c3 | 199 | req->flags |= flags | REQ_BLOCK_PC | REQ_SPECIAL | REQ_QUIET; |
39216033 JB |
200 | |
201 | /* | |
202 | * head injection *required* here otherwise quiesce won't work | |
203 | */ | |
204 | blk_execute_rq(req->q, NULL, req, 1); | |
205 | ||
206 | ret = req->errors; | |
207 | out: | |
208 | blk_put_request(req); | |
209 | ||
210 | return ret; | |
211 | } | |
33aa687d | 212 | EXPORT_SYMBOL(scsi_execute); |
39216033 | 213 | |
ea73a9f2 JB |
214 | |
215 | int scsi_execute_req(struct scsi_device *sdev, const unsigned char *cmd, | |
216 | int data_direction, void *buffer, unsigned bufflen, | |
217 | struct scsi_sense_hdr *sshdr, int timeout, int retries) | |
218 | { | |
219 | char *sense = NULL; | |
1ccb48bb | 220 | int result; |
221 | ||
ea73a9f2 | 222 | if (sshdr) { |
24669f75 | 223 | sense = kzalloc(SCSI_SENSE_BUFFERSIZE, GFP_NOIO); |
ea73a9f2 JB |
224 | if (!sense) |
225 | return DRIVER_ERROR << 24; | |
ea73a9f2 | 226 | } |
1ccb48bb | 227 | result = scsi_execute(sdev, cmd, data_direction, buffer, bufflen, |
24669f75 | 228 | sense, timeout, retries, 0); |
ea73a9f2 | 229 | if (sshdr) |
e514385b | 230 | scsi_normalize_sense(sense, SCSI_SENSE_BUFFERSIZE, sshdr); |
ea73a9f2 JB |
231 | |
232 | kfree(sense); | |
233 | return result; | |
234 | } | |
235 | EXPORT_SYMBOL(scsi_execute_req); | |
236 | ||
6e68af66 MC |
237 | struct scsi_io_context { |
238 | void *data; | |
239 | void (*done)(void *data, char *sense, int result, int resid); | |
240 | char sense[SCSI_SENSE_BUFFERSIZE]; | |
241 | }; | |
242 | ||
aa7b5cd7 MC |
243 | static kmem_cache_t *scsi_io_context_cache; |
244 | ||
e650c305 | 245 | static void scsi_end_async(struct request *req, int uptodate) |
6e68af66 MC |
246 | { |
247 | struct scsi_io_context *sioc = req->end_io_data; | |
248 | ||
249 | if (sioc->done) | |
250 | sioc->done(sioc->data, sioc->sense, req->errors, req->data_len); | |
251 | ||
aa7b5cd7 | 252 | kmem_cache_free(scsi_io_context_cache, sioc); |
6e68af66 MC |
253 | __blk_put_request(req->q, req); |
254 | } | |
255 | ||
256 | static int scsi_merge_bio(struct request *rq, struct bio *bio) | |
257 | { | |
258 | struct request_queue *q = rq->q; | |
259 | ||
260 | bio->bi_flags &= ~(1 << BIO_SEG_VALID); | |
261 | if (rq_data_dir(rq) == WRITE) | |
262 | bio->bi_rw |= (1 << BIO_RW); | |
263 | blk_queue_bounce(q, &bio); | |
264 | ||
265 | if (!rq->bio) | |
266 | blk_rq_bio_prep(q, rq, bio); | |
267 | else if (!q->back_merge_fn(q, rq, bio)) | |
268 | return -EINVAL; | |
269 | else { | |
270 | rq->biotail->bi_next = bio; | |
271 | rq->biotail = bio; | |
272 | rq->hard_nr_sectors += bio_sectors(bio); | |
273 | rq->nr_sectors = rq->hard_nr_sectors; | |
274 | } | |
275 | ||
276 | return 0; | |
277 | } | |
278 | ||
279 | static int scsi_bi_endio(struct bio *bio, unsigned int bytes_done, int error) | |
280 | { | |
281 | if (bio->bi_size) | |
282 | return 1; | |
283 | ||
284 | bio_put(bio); | |
285 | return 0; | |
286 | } | |
287 | ||
288 | /** | |
289 | * scsi_req_map_sg - map a scatterlist into a request | |
290 | * @rq: request to fill | |
291 | * @sg: scatterlist | |
292 | * @nsegs: number of elements | |
293 | * @bufflen: len of buffer | |
294 | * @gfp: memory allocation flags | |
295 | * | |
296 | * scsi_req_map_sg maps a scatterlist into a request so that the | |
297 | * request can be sent to the block layer. We do not trust the scatterlist | |
298 | * sent to use, as some ULDs use that struct to only organize the pages. | |
299 | */ | |
300 | static int scsi_req_map_sg(struct request *rq, struct scatterlist *sgl, | |
301 | int nsegs, unsigned bufflen, gfp_t gfp) | |
302 | { | |
303 | struct request_queue *q = rq->q; | |
f5235962 | 304 | int nr_pages = (bufflen + sgl[0].offset + PAGE_SIZE - 1) >> PAGE_SHIFT; |
6e68af66 MC |
305 | unsigned int data_len = 0, len, bytes, off; |
306 | struct page *page; | |
307 | struct bio *bio = NULL; | |
308 | int i, err, nr_vecs = 0; | |
309 | ||
310 | for (i = 0; i < nsegs; i++) { | |
311 | page = sgl[i].page; | |
312 | off = sgl[i].offset; | |
313 | len = sgl[i].length; | |
314 | data_len += len; | |
315 | ||
316 | while (len > 0) { | |
317 | bytes = min_t(unsigned int, len, PAGE_SIZE - off); | |
318 | ||
319 | if (!bio) { | |
320 | nr_vecs = min_t(int, BIO_MAX_PAGES, nr_pages); | |
321 | nr_pages -= nr_vecs; | |
322 | ||
323 | bio = bio_alloc(gfp, nr_vecs); | |
324 | if (!bio) { | |
325 | err = -ENOMEM; | |
326 | goto free_bios; | |
327 | } | |
328 | bio->bi_end_io = scsi_bi_endio; | |
329 | } | |
330 | ||
331 | if (bio_add_pc_page(q, bio, page, bytes, off) != | |
332 | bytes) { | |
333 | bio_put(bio); | |
334 | err = -EINVAL; | |
335 | goto free_bios; | |
336 | } | |
337 | ||
338 | if (bio->bi_vcnt >= nr_vecs) { | |
339 | err = scsi_merge_bio(rq, bio); | |
340 | if (err) { | |
341 | bio_endio(bio, bio->bi_size, 0); | |
342 | goto free_bios; | |
343 | } | |
344 | bio = NULL; | |
345 | } | |
346 | ||
347 | page++; | |
348 | len -= bytes; | |
349 | off = 0; | |
350 | } | |
351 | } | |
352 | ||
353 | rq->buffer = rq->data = NULL; | |
354 | rq->data_len = data_len; | |
355 | return 0; | |
356 | ||
357 | free_bios: | |
358 | while ((bio = rq->bio) != NULL) { | |
359 | rq->bio = bio->bi_next; | |
360 | /* | |
361 | * call endio instead of bio_put incase it was bounced | |
362 | */ | |
363 | bio_endio(bio, bio->bi_size, 0); | |
364 | } | |
365 | ||
366 | return err; | |
367 | } | |
368 | ||
369 | /** | |
370 | * scsi_execute_async - insert request | |
371 | * @sdev: scsi device | |
372 | * @cmd: scsi command | |
bb1d1073 | 373 | * @cmd_len: length of scsi cdb |
6e68af66 MC |
374 | * @data_direction: data direction |
375 | * @buffer: data buffer (this can be a kernel buffer or scatterlist) | |
376 | * @bufflen: len of buffer | |
377 | * @use_sg: if buffer is a scatterlist this is the number of elements | |
378 | * @timeout: request timeout in seconds | |
379 | * @retries: number of times to retry request | |
380 | * @flags: or into request flags | |
381 | **/ | |
382 | int scsi_execute_async(struct scsi_device *sdev, const unsigned char *cmd, | |
bb1d1073 | 383 | int cmd_len, int data_direction, void *buffer, unsigned bufflen, |
6e68af66 MC |
384 | int use_sg, int timeout, int retries, void *privdata, |
385 | void (*done)(void *, char *, int, int), gfp_t gfp) | |
386 | { | |
387 | struct request *req; | |
388 | struct scsi_io_context *sioc; | |
389 | int err = 0; | |
390 | int write = (data_direction == DMA_TO_DEVICE); | |
391 | ||
aa7b5cd7 | 392 | sioc = kmem_cache_alloc(scsi_io_context_cache, gfp); |
6e68af66 MC |
393 | if (!sioc) |
394 | return DRIVER_ERROR << 24; | |
aa7b5cd7 | 395 | memset(sioc, 0, sizeof(*sioc)); |
6e68af66 MC |
396 | |
397 | req = blk_get_request(sdev->request_queue, write, gfp); | |
398 | if (!req) | |
399 | goto free_sense; | |
defd94b7 | 400 | req->flags |= REQ_BLOCK_PC | REQ_QUIET; |
6e68af66 MC |
401 | |
402 | if (use_sg) | |
403 | err = scsi_req_map_sg(req, buffer, use_sg, bufflen, gfp); | |
404 | else if (bufflen) | |
405 | err = blk_rq_map_kern(req->q, req, buffer, bufflen, gfp); | |
406 | ||
407 | if (err) | |
408 | goto free_req; | |
409 | ||
bb1d1073 | 410 | req->cmd_len = cmd_len; |
6e68af66 MC |
411 | memcpy(req->cmd, cmd, req->cmd_len); |
412 | req->sense = sioc->sense; | |
413 | req->sense_len = 0; | |
414 | req->timeout = timeout; | |
17e01f21 | 415 | req->retries = retries; |
6e68af66 MC |
416 | req->end_io_data = sioc; |
417 | ||
418 | sioc->data = privdata; | |
419 | sioc->done = done; | |
420 | ||
421 | blk_execute_rq_nowait(req->q, NULL, req, 1, scsi_end_async); | |
422 | return 0; | |
423 | ||
424 | free_req: | |
425 | blk_put_request(req); | |
426 | free_sense: | |
427 | kfree(sioc); | |
428 | return DRIVER_ERROR << 24; | |
429 | } | |
430 | EXPORT_SYMBOL_GPL(scsi_execute_async); | |
431 | ||
1da177e4 LT |
432 | /* |
433 | * Function: scsi_init_cmd_errh() | |
434 | * | |
435 | * Purpose: Initialize cmd fields related to error handling. | |
436 | * | |
437 | * Arguments: cmd - command that is ready to be queued. | |
438 | * | |
439 | * Returns: Nothing | |
440 | * | |
441 | * Notes: This function has the job of initializing a number of | |
442 | * fields related to error handling. Typically this will | |
443 | * be called once for each command, as required. | |
444 | */ | |
445 | static int scsi_init_cmd_errh(struct scsi_cmnd *cmd) | |
446 | { | |
1da177e4 | 447 | cmd->serial_number = 0; |
1da177e4 LT |
448 | |
449 | memset(cmd->sense_buffer, 0, sizeof cmd->sense_buffer); | |
450 | ||
451 | if (cmd->cmd_len == 0) | |
452 | cmd->cmd_len = COMMAND_SIZE(cmd->cmnd[0]); | |
453 | ||
454 | /* | |
455 | * We need saved copies of a number of fields - this is because | |
456 | * error handling may need to overwrite these with different values | |
457 | * to run different commands, and once error handling is complete, | |
458 | * we will need to restore these values prior to running the actual | |
459 | * command. | |
460 | */ | |
461 | cmd->old_use_sg = cmd->use_sg; | |
462 | cmd->old_cmd_len = cmd->cmd_len; | |
463 | cmd->sc_old_data_direction = cmd->sc_data_direction; | |
464 | cmd->old_underflow = cmd->underflow; | |
465 | memcpy(cmd->data_cmnd, cmd->cmnd, sizeof(cmd->cmnd)); | |
466 | cmd->buffer = cmd->request_buffer; | |
467 | cmd->bufflen = cmd->request_bufflen; | |
1da177e4 LT |
468 | |
469 | return 1; | |
470 | } | |
471 | ||
472 | /* | |
473 | * Function: scsi_setup_cmd_retry() | |
474 | * | |
475 | * Purpose: Restore the command state for a retry | |
476 | * | |
477 | * Arguments: cmd - command to be restored | |
478 | * | |
479 | * Returns: Nothing | |
480 | * | |
481 | * Notes: Immediately prior to retrying a command, we need | |
482 | * to restore certain fields that we saved above. | |
483 | */ | |
484 | void scsi_setup_cmd_retry(struct scsi_cmnd *cmd) | |
485 | { | |
486 | memcpy(cmd->cmnd, cmd->data_cmnd, sizeof(cmd->data_cmnd)); | |
487 | cmd->request_buffer = cmd->buffer; | |
488 | cmd->request_bufflen = cmd->bufflen; | |
489 | cmd->use_sg = cmd->old_use_sg; | |
490 | cmd->cmd_len = cmd->old_cmd_len; | |
491 | cmd->sc_data_direction = cmd->sc_old_data_direction; | |
492 | cmd->underflow = cmd->old_underflow; | |
493 | } | |
494 | ||
495 | void scsi_device_unbusy(struct scsi_device *sdev) | |
496 | { | |
497 | struct Scsi_Host *shost = sdev->host; | |
498 | unsigned long flags; | |
499 | ||
500 | spin_lock_irqsave(shost->host_lock, flags); | |
501 | shost->host_busy--; | |
939647ee | 502 | if (unlikely(scsi_host_in_recovery(shost) && |
ee7863bc | 503 | (shost->host_failed || shost->host_eh_scheduled))) |
1da177e4 LT |
504 | scsi_eh_wakeup(shost); |
505 | spin_unlock(shost->host_lock); | |
152587de | 506 | spin_lock(sdev->request_queue->queue_lock); |
1da177e4 | 507 | sdev->device_busy--; |
152587de | 508 | spin_unlock_irqrestore(sdev->request_queue->queue_lock, flags); |
1da177e4 LT |
509 | } |
510 | ||
511 | /* | |
512 | * Called for single_lun devices on IO completion. Clear starget_sdev_user, | |
513 | * and call blk_run_queue for all the scsi_devices on the target - | |
514 | * including current_sdev first. | |
515 | * | |
516 | * Called with *no* scsi locks held. | |
517 | */ | |
518 | static void scsi_single_lun_run(struct scsi_device *current_sdev) | |
519 | { | |
520 | struct Scsi_Host *shost = current_sdev->host; | |
521 | struct scsi_device *sdev, *tmp; | |
522 | struct scsi_target *starget = scsi_target(current_sdev); | |
523 | unsigned long flags; | |
524 | ||
525 | spin_lock_irqsave(shost->host_lock, flags); | |
526 | starget->starget_sdev_user = NULL; | |
527 | spin_unlock_irqrestore(shost->host_lock, flags); | |
528 | ||
529 | /* | |
530 | * Call blk_run_queue for all LUNs on the target, starting with | |
531 | * current_sdev. We race with others (to set starget_sdev_user), | |
532 | * but in most cases, we will be first. Ideally, each LU on the | |
533 | * target would get some limited time or requests on the target. | |
534 | */ | |
535 | blk_run_queue(current_sdev->request_queue); | |
536 | ||
537 | spin_lock_irqsave(shost->host_lock, flags); | |
538 | if (starget->starget_sdev_user) | |
539 | goto out; | |
540 | list_for_each_entry_safe(sdev, tmp, &starget->devices, | |
541 | same_target_siblings) { | |
542 | if (sdev == current_sdev) | |
543 | continue; | |
544 | if (scsi_device_get(sdev)) | |
545 | continue; | |
546 | ||
547 | spin_unlock_irqrestore(shost->host_lock, flags); | |
548 | blk_run_queue(sdev->request_queue); | |
549 | spin_lock_irqsave(shost->host_lock, flags); | |
550 | ||
551 | scsi_device_put(sdev); | |
552 | } | |
553 | out: | |
554 | spin_unlock_irqrestore(shost->host_lock, flags); | |
555 | } | |
556 | ||
557 | /* | |
558 | * Function: scsi_run_queue() | |
559 | * | |
560 | * Purpose: Select a proper request queue to serve next | |
561 | * | |
562 | * Arguments: q - last request's queue | |
563 | * | |
564 | * Returns: Nothing | |
565 | * | |
566 | * Notes: The previous command was completely finished, start | |
567 | * a new one if possible. | |
568 | */ | |
569 | static void scsi_run_queue(struct request_queue *q) | |
570 | { | |
571 | struct scsi_device *sdev = q->queuedata; | |
572 | struct Scsi_Host *shost = sdev->host; | |
573 | unsigned long flags; | |
574 | ||
575 | if (sdev->single_lun) | |
576 | scsi_single_lun_run(sdev); | |
577 | ||
578 | spin_lock_irqsave(shost->host_lock, flags); | |
579 | while (!list_empty(&shost->starved_list) && | |
580 | !shost->host_blocked && !shost->host_self_blocked && | |
581 | !((shost->can_queue > 0) && | |
582 | (shost->host_busy >= shost->can_queue))) { | |
583 | /* | |
584 | * As long as shost is accepting commands and we have | |
585 | * starved queues, call blk_run_queue. scsi_request_fn | |
586 | * drops the queue_lock and can add us back to the | |
587 | * starved_list. | |
588 | * | |
589 | * host_lock protects the starved_list and starved_entry. | |
590 | * scsi_request_fn must get the host_lock before checking | |
591 | * or modifying starved_list or starved_entry. | |
592 | */ | |
593 | sdev = list_entry(shost->starved_list.next, | |
594 | struct scsi_device, starved_entry); | |
595 | list_del_init(&sdev->starved_entry); | |
596 | spin_unlock_irqrestore(shost->host_lock, flags); | |
597 | ||
598 | blk_run_queue(sdev->request_queue); | |
599 | ||
600 | spin_lock_irqsave(shost->host_lock, flags); | |
601 | if (unlikely(!list_empty(&sdev->starved_entry))) | |
602 | /* | |
603 | * sdev lost a race, and was put back on the | |
604 | * starved list. This is unlikely but without this | |
605 | * in theory we could loop forever. | |
606 | */ | |
607 | break; | |
608 | } | |
609 | spin_unlock_irqrestore(shost->host_lock, flags); | |
610 | ||
611 | blk_run_queue(q); | |
612 | } | |
613 | ||
614 | /* | |
615 | * Function: scsi_requeue_command() | |
616 | * | |
617 | * Purpose: Handle post-processing of completed commands. | |
618 | * | |
619 | * Arguments: q - queue to operate on | |
620 | * cmd - command that may need to be requeued. | |
621 | * | |
622 | * Returns: Nothing | |
623 | * | |
624 | * Notes: After command completion, there may be blocks left | |
625 | * over which weren't finished by the previous command | |
626 | * this can be for a number of reasons - the main one is | |
627 | * I/O errors in the middle of the request, in which case | |
628 | * we need to request the blocks that come after the bad | |
629 | * sector. | |
e91442b6 | 630 | * Notes: Upon return, cmd is a stale pointer. |
1da177e4 LT |
631 | */ |
632 | static void scsi_requeue_command(struct request_queue *q, struct scsi_cmnd *cmd) | |
633 | { | |
e91442b6 | 634 | struct request *req = cmd->request; |
283369cc TH |
635 | unsigned long flags; |
636 | ||
e91442b6 | 637 | scsi_unprep_request(req); |
283369cc | 638 | spin_lock_irqsave(q->queue_lock, flags); |
e91442b6 | 639 | blk_requeue_request(q, req); |
283369cc | 640 | spin_unlock_irqrestore(q->queue_lock, flags); |
1da177e4 LT |
641 | |
642 | scsi_run_queue(q); | |
643 | } | |
644 | ||
645 | void scsi_next_command(struct scsi_cmnd *cmd) | |
646 | { | |
49d7bc64 LT |
647 | struct scsi_device *sdev = cmd->device; |
648 | struct request_queue *q = sdev->request_queue; | |
649 | ||
650 | /* need to hold a reference on the device before we let go of the cmd */ | |
651 | get_device(&sdev->sdev_gendev); | |
1da177e4 LT |
652 | |
653 | scsi_put_command(cmd); | |
654 | scsi_run_queue(q); | |
49d7bc64 LT |
655 | |
656 | /* ok to remove device now */ | |
657 | put_device(&sdev->sdev_gendev); | |
1da177e4 LT |
658 | } |
659 | ||
660 | void scsi_run_host_queues(struct Scsi_Host *shost) | |
661 | { | |
662 | struct scsi_device *sdev; | |
663 | ||
664 | shost_for_each_device(sdev, shost) | |
665 | scsi_run_queue(sdev->request_queue); | |
666 | } | |
667 | ||
668 | /* | |
669 | * Function: scsi_end_request() | |
670 | * | |
671 | * Purpose: Post-processing of completed commands (usually invoked at end | |
672 | * of upper level post-processing and scsi_io_completion). | |
673 | * | |
674 | * Arguments: cmd - command that is complete. | |
675 | * uptodate - 1 if I/O indicates success, <= 0 for I/O error. | |
676 | * bytes - number of bytes of completed I/O | |
677 | * requeue - indicates whether we should requeue leftovers. | |
678 | * | |
679 | * Lock status: Assumed that lock is not held upon entry. | |
680 | * | |
e91442b6 | 681 | * Returns: cmd if requeue required, NULL otherwise. |
1da177e4 LT |
682 | * |
683 | * Notes: This is called for block device requests in order to | |
684 | * mark some number of sectors as complete. | |
685 | * | |
686 | * We are guaranteeing that the request queue will be goosed | |
687 | * at some point during this call. | |
e91442b6 | 688 | * Notes: If cmd was requeued, upon return it will be a stale pointer. |
1da177e4 LT |
689 | */ |
690 | static struct scsi_cmnd *scsi_end_request(struct scsi_cmnd *cmd, int uptodate, | |
691 | int bytes, int requeue) | |
692 | { | |
693 | request_queue_t *q = cmd->device->request_queue; | |
694 | struct request *req = cmd->request; | |
695 | unsigned long flags; | |
696 | ||
697 | /* | |
698 | * If there are blocks left over at the end, set up the command | |
699 | * to queue the remainder of them. | |
700 | */ | |
701 | if (end_that_request_chunk(req, uptodate, bytes)) { | |
702 | int leftover = (req->hard_nr_sectors << 9); | |
703 | ||
704 | if (blk_pc_request(req)) | |
705 | leftover = req->data_len; | |
706 | ||
707 | /* kill remainder if no retrys */ | |
708 | if (!uptodate && blk_noretry_request(req)) | |
709 | end_that_request_chunk(req, 0, leftover); | |
710 | else { | |
e91442b6 | 711 | if (requeue) { |
1da177e4 LT |
712 | /* |
713 | * Bleah. Leftovers again. Stick the | |
714 | * leftovers in the front of the | |
715 | * queue, and goose the queue again. | |
716 | */ | |
717 | scsi_requeue_command(q, cmd); | |
e91442b6 JB |
718 | cmd = NULL; |
719 | } | |
1da177e4 LT |
720 | return cmd; |
721 | } | |
722 | } | |
723 | ||
724 | add_disk_randomness(req->rq_disk); | |
725 | ||
726 | spin_lock_irqsave(q->queue_lock, flags); | |
727 | if (blk_rq_tagged(req)) | |
728 | blk_queue_end_tag(q, req); | |
8ffdc655 | 729 | end_that_request_last(req, uptodate); |
1da177e4 LT |
730 | spin_unlock_irqrestore(q->queue_lock, flags); |
731 | ||
732 | /* | |
733 | * This will goose the queue request function at the end, so we don't | |
734 | * need to worry about launching another command. | |
735 | */ | |
736 | scsi_next_command(cmd); | |
737 | return NULL; | |
738 | } | |
739 | ||
c53033f6 | 740 | static struct scatterlist *scsi_alloc_sgtable(struct scsi_cmnd *cmd, gfp_t gfp_mask) |
1da177e4 LT |
741 | { |
742 | struct scsi_host_sg_pool *sgp; | |
743 | struct scatterlist *sgl; | |
744 | ||
745 | BUG_ON(!cmd->use_sg); | |
746 | ||
747 | switch (cmd->use_sg) { | |
748 | case 1 ... 8: | |
749 | cmd->sglist_len = 0; | |
750 | break; | |
751 | case 9 ... 16: | |
752 | cmd->sglist_len = 1; | |
753 | break; | |
754 | case 17 ... 32: | |
755 | cmd->sglist_len = 2; | |
756 | break; | |
757 | #if (SCSI_MAX_PHYS_SEGMENTS > 32) | |
758 | case 33 ... 64: | |
759 | cmd->sglist_len = 3; | |
760 | break; | |
761 | #if (SCSI_MAX_PHYS_SEGMENTS > 64) | |
762 | case 65 ... 128: | |
763 | cmd->sglist_len = 4; | |
764 | break; | |
765 | #if (SCSI_MAX_PHYS_SEGMENTS > 128) | |
766 | case 129 ... 256: | |
767 | cmd->sglist_len = 5; | |
768 | break; | |
769 | #endif | |
770 | #endif | |
771 | #endif | |
772 | default: | |
773 | return NULL; | |
774 | } | |
775 | ||
776 | sgp = scsi_sg_pools + cmd->sglist_len; | |
777 | sgl = mempool_alloc(sgp->pool, gfp_mask); | |
1da177e4 LT |
778 | return sgl; |
779 | } | |
780 | ||
781 | static void scsi_free_sgtable(struct scatterlist *sgl, int index) | |
782 | { | |
783 | struct scsi_host_sg_pool *sgp; | |
784 | ||
a77e3362 | 785 | BUG_ON(index >= SG_MEMPOOL_NR); |
1da177e4 LT |
786 | |
787 | sgp = scsi_sg_pools + index; | |
788 | mempool_free(sgl, sgp->pool); | |
789 | } | |
790 | ||
791 | /* | |
792 | * Function: scsi_release_buffers() | |
793 | * | |
794 | * Purpose: Completion processing for block device I/O requests. | |
795 | * | |
796 | * Arguments: cmd - command that we are bailing. | |
797 | * | |
798 | * Lock status: Assumed that no lock is held upon entry. | |
799 | * | |
800 | * Returns: Nothing | |
801 | * | |
802 | * Notes: In the event that an upper level driver rejects a | |
803 | * command, we must release resources allocated during | |
804 | * the __init_io() function. Primarily this would involve | |
805 | * the scatter-gather table, and potentially any bounce | |
806 | * buffers. | |
807 | */ | |
808 | static void scsi_release_buffers(struct scsi_cmnd *cmd) | |
809 | { | |
810 | struct request *req = cmd->request; | |
811 | ||
812 | /* | |
813 | * Free up any indirection buffers we allocated for DMA purposes. | |
814 | */ | |
815 | if (cmd->use_sg) | |
816 | scsi_free_sgtable(cmd->request_buffer, cmd->sglist_len); | |
817 | else if (cmd->request_buffer != req->buffer) | |
818 | kfree(cmd->request_buffer); | |
819 | ||
820 | /* | |
821 | * Zero these out. They now point to freed memory, and it is | |
822 | * dangerous to hang onto the pointers. | |
823 | */ | |
824 | cmd->buffer = NULL; | |
825 | cmd->bufflen = 0; | |
826 | cmd->request_buffer = NULL; | |
827 | cmd->request_bufflen = 0; | |
828 | } | |
829 | ||
830 | /* | |
831 | * Function: scsi_io_completion() | |
832 | * | |
833 | * Purpose: Completion processing for block device I/O requests. | |
834 | * | |
835 | * Arguments: cmd - command that is finished. | |
836 | * | |
837 | * Lock status: Assumed that no lock is held upon entry. | |
838 | * | |
839 | * Returns: Nothing | |
840 | * | |
841 | * Notes: This function is matched in terms of capabilities to | |
842 | * the function that created the scatter-gather list. | |
843 | * In other words, if there are no bounce buffers | |
844 | * (the normal case for most drivers), we don't need | |
845 | * the logic to deal with cleaning up afterwards. | |
846 | * | |
847 | * We must do one of several things here: | |
848 | * | |
849 | * a) Call scsi_end_request. This will finish off the | |
850 | * specified number of sectors. If we are done, the | |
851 | * command block will be released, and the queue | |
852 | * function will be goosed. If we are not done, then | |
853 | * scsi_end_request will directly goose the queue. | |
854 | * | |
855 | * b) We can just use scsi_requeue_command() here. This would | |
856 | * be used if we just wanted to retry, for example. | |
857 | */ | |
858 | void scsi_io_completion(struct scsi_cmnd *cmd, unsigned int good_bytes, | |
859 | unsigned int block_bytes) | |
860 | { | |
861 | int result = cmd->result; | |
862 | int this_count = cmd->bufflen; | |
863 | request_queue_t *q = cmd->device->request_queue; | |
864 | struct request *req = cmd->request; | |
865 | int clear_errors = 1; | |
866 | struct scsi_sense_hdr sshdr; | |
867 | int sense_valid = 0; | |
868 | int sense_deferred = 0; | |
869 | ||
1da177e4 LT |
870 | /* |
871 | * Free up any indirection buffers we allocated for DMA purposes. | |
872 | * For the case of a READ, we need to copy the data out of the | |
873 | * bounce buffer and into the real buffer. | |
874 | */ | |
875 | if (cmd->use_sg) | |
876 | scsi_free_sgtable(cmd->buffer, cmd->sglist_len); | |
877 | else if (cmd->buffer != req->buffer) { | |
878 | if (rq_data_dir(req) == READ) { | |
879 | unsigned long flags; | |
880 | char *to = bio_kmap_irq(req->bio, &flags); | |
881 | memcpy(to, cmd->buffer, cmd->bufflen); | |
882 | bio_kunmap_irq(to, &flags); | |
883 | } | |
884 | kfree(cmd->buffer); | |
885 | } | |
886 | ||
887 | if (result) { | |
888 | sense_valid = scsi_command_normalize_sense(cmd, &sshdr); | |
889 | if (sense_valid) | |
890 | sense_deferred = scsi_sense_is_deferred(&sshdr); | |
891 | } | |
892 | if (blk_pc_request(req)) { /* SG_IO ioctl from block level */ | |
893 | req->errors = result; | |
894 | if (result) { | |
895 | clear_errors = 0; | |
896 | if (sense_valid && req->sense) { | |
897 | /* | |
898 | * SG_IO wants current and deferred errors | |
899 | */ | |
900 | int len = 8 + cmd->sense_buffer[7]; | |
901 | ||
902 | if (len > SCSI_SENSE_BUFFERSIZE) | |
903 | len = SCSI_SENSE_BUFFERSIZE; | |
904 | memcpy(req->sense, cmd->sense_buffer, len); | |
905 | req->sense_len = len; | |
906 | } | |
907 | } else | |
908 | req->data_len = cmd->resid; | |
909 | } | |
910 | ||
911 | /* | |
912 | * Zero these out. They now point to freed memory, and it is | |
913 | * dangerous to hang onto the pointers. | |
914 | */ | |
915 | cmd->buffer = NULL; | |
916 | cmd->bufflen = 0; | |
917 | cmd->request_buffer = NULL; | |
918 | cmd->request_bufflen = 0; | |
919 | ||
920 | /* | |
921 | * Next deal with any sectors which we were able to correctly | |
922 | * handle. | |
923 | */ | |
924 | if (good_bytes >= 0) { | |
925 | SCSI_LOG_HLCOMPLETE(1, printk("%ld sectors total, %d bytes done.\n", | |
926 | req->nr_sectors, good_bytes)); | |
927 | SCSI_LOG_HLCOMPLETE(1, printk("use_sg is %d\n", cmd->use_sg)); | |
928 | ||
929 | if (clear_errors) | |
930 | req->errors = 0; | |
931 | /* | |
932 | * If multiple sectors are requested in one buffer, then | |
933 | * they will have been finished off by the first command. | |
934 | * If not, then we have a multi-buffer command. | |
935 | * | |
936 | * If block_bytes != 0, it means we had a medium error | |
937 | * of some sort, and that we want to mark some number of | |
938 | * sectors as not uptodate. Thus we want to inhibit | |
939 | * requeueing right here - we will requeue down below | |
940 | * when we handle the bad sectors. | |
941 | */ | |
1da177e4 LT |
942 | |
943 | /* | |
e91442b6 JB |
944 | * If the command completed without error, then either |
945 | * finish off the rest of the command, or start a new one. | |
1da177e4 | 946 | */ |
e91442b6 | 947 | if (scsi_end_request(cmd, 1, good_bytes, result == 0) == NULL) |
1da177e4 | 948 | return; |
1da177e4 LT |
949 | } |
950 | /* | |
951 | * Now, if we were good little boys and girls, Santa left us a request | |
952 | * sense buffer. We can extract information from this, so we | |
953 | * can choose a block to remap, etc. | |
954 | */ | |
955 | if (sense_valid && !sense_deferred) { | |
956 | switch (sshdr.sense_key) { | |
957 | case UNIT_ATTENTION: | |
958 | if (cmd->device->removable) { | |
959 | /* detected disc change. set a bit | |
960 | * and quietly refuse further access. | |
961 | */ | |
962 | cmd->device->changed = 1; | |
e91442b6 | 963 | scsi_end_request(cmd, 0, |
1da177e4 LT |
964 | this_count, 1); |
965 | return; | |
966 | } else { | |
967 | /* | |
968 | * Must have been a power glitch, or a | |
969 | * bus reset. Could not have been a | |
970 | * media change, so we just retry the | |
971 | * request and see what happens. | |
972 | */ | |
973 | scsi_requeue_command(q, cmd); | |
974 | return; | |
975 | } | |
976 | break; | |
977 | case ILLEGAL_REQUEST: | |
978 | /* | |
979 | * If we had an ILLEGAL REQUEST returned, then we may | |
980 | * have performed an unsupported command. The only | |
981 | * thing this should be would be a ten byte read where | |
982 | * only a six byte read was supported. Also, on a | |
983 | * system where READ CAPACITY failed, we may have read | |
984 | * past the end of the disk. | |
985 | */ | |
26a68019 JA |
986 | if ((cmd->device->use_10_for_rw && |
987 | sshdr.asc == 0x20 && sshdr.ascq == 0x00) && | |
1da177e4 LT |
988 | (cmd->cmnd[0] == READ_10 || |
989 | cmd->cmnd[0] == WRITE_10)) { | |
990 | cmd->device->use_10_for_rw = 0; | |
991 | /* | |
992 | * This will cause a retry with a 6-byte | |
993 | * command. | |
994 | */ | |
995 | scsi_requeue_command(q, cmd); | |
996 | result = 0; | |
997 | } else { | |
e91442b6 | 998 | scsi_end_request(cmd, 0, this_count, 1); |
1da177e4 LT |
999 | return; |
1000 | } | |
1001 | break; | |
1002 | case NOT_READY: | |
1003 | /* | |
f3e93f73 JB |
1004 | * If the device is in the process of becoming |
1005 | * ready, or has a temporary blockage, retry. | |
1da177e4 | 1006 | */ |
f3e93f73 JB |
1007 | if (sshdr.asc == 0x04) { |
1008 | switch (sshdr.ascq) { | |
1009 | case 0x01: /* becoming ready */ | |
1010 | case 0x04: /* format in progress */ | |
1011 | case 0x05: /* rebuild in progress */ | |
1012 | case 0x06: /* recalculation in progress */ | |
1013 | case 0x07: /* operation in progress */ | |
1014 | case 0x08: /* Long write in progress */ | |
1015 | case 0x09: /* self test in progress */ | |
1016 | scsi_requeue_command(q, cmd); | |
1017 | return; | |
1018 | default: | |
1019 | break; | |
1020 | } | |
1da177e4 | 1021 | } |
f3e93f73 | 1022 | if (!(req->flags & REQ_QUIET)) { |
3bf743e7 | 1023 | scmd_printk(KERN_INFO, cmd, |
f3e93f73 JB |
1024 | "Device not ready: "); |
1025 | scsi_print_sense_hdr("", &sshdr); | |
1026 | } | |
e91442b6 | 1027 | scsi_end_request(cmd, 0, this_count, 1); |
1da177e4 LT |
1028 | return; |
1029 | case VOLUME_OVERFLOW: | |
3173d8c3 | 1030 | if (!(req->flags & REQ_QUIET)) { |
3bf743e7 JG |
1031 | scmd_printk(KERN_INFO, cmd, |
1032 | "Volume overflow, CDB: "); | |
3173d8c3 JB |
1033 | __scsi_print_command(cmd->data_cmnd); |
1034 | scsi_print_sense("", cmd); | |
1035 | } | |
e91442b6 | 1036 | scsi_end_request(cmd, 0, block_bytes, 1); |
1da177e4 LT |
1037 | return; |
1038 | default: | |
1039 | break; | |
1040 | } | |
1041 | } /* driver byte != 0 */ | |
1042 | if (host_byte(result) == DID_RESET) { | |
1043 | /* | |
1044 | * Third party bus reset or reset for error | |
1045 | * recovery reasons. Just retry the request | |
1046 | * and see what happens. | |
1047 | */ | |
1048 | scsi_requeue_command(q, cmd); | |
1049 | return; | |
1050 | } | |
1051 | if (result) { | |
3173d8c3 | 1052 | if (!(req->flags & REQ_QUIET)) { |
3bf743e7 JG |
1053 | scmd_printk(KERN_INFO, cmd, |
1054 | "SCSI error: return code = 0x%x\n", result); | |
3173d8c3 JB |
1055 | |
1056 | if (driver_byte(result) & DRIVER_SENSE) | |
1057 | scsi_print_sense("", cmd); | |
1058 | } | |
1da177e4 LT |
1059 | /* |
1060 | * Mark a single buffer as not uptodate. Queue the remainder. | |
1061 | * We sometimes get this cruft in the event that a medium error | |
1062 | * isn't properly reported. | |
1063 | */ | |
1064 | block_bytes = req->hard_cur_sectors << 9; | |
1065 | if (!block_bytes) | |
1066 | block_bytes = req->data_len; | |
e91442b6 | 1067 | scsi_end_request(cmd, 0, block_bytes, 1); |
1da177e4 LT |
1068 | } |
1069 | } | |
1070 | EXPORT_SYMBOL(scsi_io_completion); | |
1071 | ||
1072 | /* | |
1073 | * Function: scsi_init_io() | |
1074 | * | |
1075 | * Purpose: SCSI I/O initialize function. | |
1076 | * | |
1077 | * Arguments: cmd - Command descriptor we wish to initialize | |
1078 | * | |
1079 | * Returns: 0 on success | |
1080 | * BLKPREP_DEFER if the failure is retryable | |
1081 | * BLKPREP_KILL if the failure is fatal | |
1082 | */ | |
1083 | static int scsi_init_io(struct scsi_cmnd *cmd) | |
1084 | { | |
1085 | struct request *req = cmd->request; | |
1086 | struct scatterlist *sgpnt; | |
1087 | int count; | |
1088 | ||
1089 | /* | |
1090 | * if this is a rq->data based REQ_BLOCK_PC, setup for a non-sg xfer | |
1091 | */ | |
1092 | if ((req->flags & REQ_BLOCK_PC) && !req->bio) { | |
1093 | cmd->request_bufflen = req->data_len; | |
1094 | cmd->request_buffer = req->data; | |
1095 | req->buffer = req->data; | |
1096 | cmd->use_sg = 0; | |
1097 | return 0; | |
1098 | } | |
1099 | ||
1100 | /* | |
1101 | * we used to not use scatter-gather for single segment request, | |
1102 | * but now we do (it makes highmem I/O easier to support without | |
1103 | * kmapping pages) | |
1104 | */ | |
1105 | cmd->use_sg = req->nr_phys_segments; | |
1106 | ||
1107 | /* | |
1108 | * if sg table allocation fails, requeue request later. | |
1109 | */ | |
1110 | sgpnt = scsi_alloc_sgtable(cmd, GFP_ATOMIC); | |
7c72ce81 AS |
1111 | if (unlikely(!sgpnt)) { |
1112 | scsi_unprep_request(req); | |
1da177e4 | 1113 | return BLKPREP_DEFER; |
7c72ce81 | 1114 | } |
1da177e4 LT |
1115 | |
1116 | cmd->request_buffer = (char *) sgpnt; | |
1117 | cmd->request_bufflen = req->nr_sectors << 9; | |
1118 | if (blk_pc_request(req)) | |
1119 | cmd->request_bufflen = req->data_len; | |
1120 | req->buffer = NULL; | |
1121 | ||
1122 | /* | |
1123 | * Next, walk the list, and fill in the addresses and sizes of | |
1124 | * each segment. | |
1125 | */ | |
1126 | count = blk_rq_map_sg(req->q, req, cmd->request_buffer); | |
1127 | ||
1128 | /* | |
1129 | * mapped well, send it off | |
1130 | */ | |
1131 | if (likely(count <= cmd->use_sg)) { | |
1132 | cmd->use_sg = count; | |
1133 | return 0; | |
1134 | } | |
1135 | ||
1136 | printk(KERN_ERR "Incorrect number of segments after building list\n"); | |
1137 | printk(KERN_ERR "counted %d, received %d\n", count, cmd->use_sg); | |
1138 | printk(KERN_ERR "req nr_sec %lu, cur_nr_sec %u\n", req->nr_sectors, | |
1139 | req->current_nr_sectors); | |
1140 | ||
1141 | /* release the command and kill it */ | |
1142 | scsi_release_buffers(cmd); | |
1143 | scsi_put_command(cmd); | |
1144 | return BLKPREP_KILL; | |
1145 | } | |
1146 | ||
1da177e4 LT |
1147 | static int scsi_issue_flush_fn(request_queue_t *q, struct gendisk *disk, |
1148 | sector_t *error_sector) | |
1149 | { | |
1150 | struct scsi_device *sdev = q->queuedata; | |
1151 | struct scsi_driver *drv; | |
1152 | ||
1153 | if (sdev->sdev_state != SDEV_RUNNING) | |
1154 | return -ENXIO; | |
1155 | ||
1156 | drv = *(struct scsi_driver **) disk->private_data; | |
1157 | if (drv->issue_flush) | |
1158 | return drv->issue_flush(&sdev->sdev_gendev, error_sector); | |
1159 | ||
1160 | return -EOPNOTSUPP; | |
1161 | } | |
1162 | ||
776b23a0 | 1163 | static void scsi_blk_pc_done(struct scsi_cmnd *cmd) |
e537a36d JB |
1164 | { |
1165 | BUG_ON(!blk_pc_request(cmd->request)); | |
0d95716d MC |
1166 | /* |
1167 | * This will complete the whole command with uptodate=1 so | |
1168 | * as far as the block layer is concerned the command completed | |
1169 | * successfully. Since this is a REQ_BLOCK_PC command the | |
1170 | * caller should check the request's errors value | |
1171 | */ | |
1172 | scsi_io_completion(cmd, cmd->bufflen, 0); | |
e537a36d JB |
1173 | } |
1174 | ||
776b23a0 | 1175 | static void scsi_setup_blk_pc_cmnd(struct scsi_cmnd *cmd) |
7b16318d JB |
1176 | { |
1177 | struct request *req = cmd->request; | |
1178 | ||
1179 | BUG_ON(sizeof(req->cmd) > sizeof(cmd->cmnd)); | |
1180 | memcpy(cmd->cmnd, req->cmd, sizeof(cmd->cmnd)); | |
1181 | cmd->cmd_len = req->cmd_len; | |
1182 | if (!req->data_len) | |
1183 | cmd->sc_data_direction = DMA_NONE; | |
1184 | else if (rq_data_dir(req) == WRITE) | |
1185 | cmd->sc_data_direction = DMA_TO_DEVICE; | |
1186 | else | |
1187 | cmd->sc_data_direction = DMA_FROM_DEVICE; | |
1188 | ||
1189 | cmd->transfersize = req->data_len; | |
1190 | cmd->allowed = req->retries; | |
1191 | cmd->timeout_per_command = req->timeout; | |
776b23a0 | 1192 | cmd->done = scsi_blk_pc_done; |
7b16318d | 1193 | } |
7b16318d | 1194 | |
1da177e4 LT |
1195 | static int scsi_prep_fn(struct request_queue *q, struct request *req) |
1196 | { | |
1197 | struct scsi_device *sdev = q->queuedata; | |
1198 | struct scsi_cmnd *cmd; | |
1199 | int specials_only = 0; | |
1200 | ||
1201 | /* | |
1202 | * Just check to see if the device is online. If it isn't, we | |
1203 | * refuse to process any commands. The device must be brought | |
1204 | * online before trying any recovery commands | |
1205 | */ | |
1206 | if (unlikely(!scsi_device_online(sdev))) { | |
9ccfc756 JB |
1207 | sdev_printk(KERN_ERR, sdev, |
1208 | "rejecting I/O to offline device\n"); | |
6f16b535 | 1209 | goto kill; |
1da177e4 LT |
1210 | } |
1211 | if (unlikely(sdev->sdev_state != SDEV_RUNNING)) { | |
1212 | /* OK, we're not in a running state don't prep | |
1213 | * user commands */ | |
1214 | if (sdev->sdev_state == SDEV_DEL) { | |
1215 | /* Device is fully deleted, no commands | |
1216 | * at all allowed down */ | |
9ccfc756 JB |
1217 | sdev_printk(KERN_ERR, sdev, |
1218 | "rejecting I/O to dead device\n"); | |
6f16b535 | 1219 | goto kill; |
1da177e4 LT |
1220 | } |
1221 | /* OK, we only allow special commands (i.e. not | |
1222 | * user initiated ones */ | |
1223 | specials_only = sdev->sdev_state; | |
1224 | } | |
1225 | ||
1226 | /* | |
1227 | * Find the actual device driver associated with this command. | |
1228 | * The SPECIAL requests are things like character device or | |
1229 | * ioctls, which did not originate from ll_rw_blk. Note that | |
1230 | * the special field is also used to indicate the cmd for | |
1231 | * the remainder of a partially fulfilled request that can | |
1232 | * come up when there is a medium error. We have to treat | |
1233 | * these two cases differently. We differentiate by looking | |
1234 | * at request->cmd, as this tells us the real story. | |
1235 | */ | |
e537a36d | 1236 | if (req->flags & REQ_SPECIAL && req->special) { |
beb40487 | 1237 | cmd = req->special; |
1da177e4 LT |
1238 | } else if (req->flags & (REQ_CMD | REQ_BLOCK_PC)) { |
1239 | ||
e537a36d | 1240 | if(unlikely(specials_only) && !(req->flags & REQ_SPECIAL)) { |
1da177e4 LT |
1241 | if(specials_only == SDEV_QUIESCE || |
1242 | specials_only == SDEV_BLOCK) | |
6f16b535 | 1243 | goto defer; |
1da177e4 | 1244 | |
9ccfc756 JB |
1245 | sdev_printk(KERN_ERR, sdev, |
1246 | "rejecting I/O to device being removed\n"); | |
6f16b535 | 1247 | goto kill; |
1da177e4 LT |
1248 | } |
1249 | ||
1250 | ||
1251 | /* | |
1252 | * Now try and find a command block that we can use. | |
1253 | */ | |
1254 | if (!req->special) { | |
1255 | cmd = scsi_get_command(sdev, GFP_ATOMIC); | |
1256 | if (unlikely(!cmd)) | |
1257 | goto defer; | |
1258 | } else | |
1259 | cmd = req->special; | |
1260 | ||
1261 | /* pull a tag out of the request if we have one */ | |
1262 | cmd->tag = req->tag; | |
1263 | } else { | |
1264 | blk_dump_rq_flags(req, "SCSI bad req"); | |
6f16b535 | 1265 | goto kill; |
1da177e4 LT |
1266 | } |
1267 | ||
1268 | /* note the overloading of req->special. When the tag | |
1269 | * is active it always means cmd. If the tag goes | |
1270 | * back for re-queueing, it may be reset */ | |
1271 | req->special = cmd; | |
1272 | cmd->request = req; | |
1273 | ||
1274 | /* | |
1275 | * FIXME: drop the lock here because the functions below | |
1276 | * expect to be called without the queue lock held. Also, | |
1277 | * previously, we dequeued the request before dropping the | |
1278 | * lock. We hope REQ_STARTED prevents anything untoward from | |
1279 | * happening now. | |
1280 | */ | |
1281 | if (req->flags & (REQ_CMD | REQ_BLOCK_PC)) { | |
1da177e4 LT |
1282 | int ret; |
1283 | ||
1284 | /* | |
1285 | * This will do a couple of things: | |
1286 | * 1) Fill in the actual SCSI command. | |
1287 | * 2) Fill in any other upper-level specific fields | |
1288 | * (timeout). | |
1289 | * | |
1290 | * If this returns 0, it means that the request failed | |
1291 | * (reading past end of disk, reading offline device, | |
1292 | * etc). This won't actually talk to the device, but | |
1293 | * some kinds of consistency checking may cause the | |
1294 | * request to be rejected immediately. | |
1295 | */ | |
1296 | ||
1297 | /* | |
1298 | * This sets up the scatter-gather table (allocating if | |
1299 | * required). | |
1300 | */ | |
1301 | ret = scsi_init_io(cmd); | |
6f16b535 | 1302 | switch(ret) { |
7c72ce81 | 1303 | /* For BLKPREP_KILL/DEFER the cmd was released */ |
6f16b535 | 1304 | case BLKPREP_KILL: |
6f16b535 MC |
1305 | goto kill; |
1306 | case BLKPREP_DEFER: | |
1307 | goto defer; | |
1308 | } | |
1da177e4 LT |
1309 | |
1310 | /* | |
1311 | * Initialize the actual SCSI command for this request. | |
1312 | */ | |
776b23a0 CH |
1313 | if (req->flags & REQ_BLOCK_PC) { |
1314 | scsi_setup_blk_pc_cmnd(cmd); | |
1315 | } else if (req->rq_disk) { | |
1316 | struct scsi_driver *drv; | |
1317 | ||
e537a36d JB |
1318 | drv = *(struct scsi_driver **)req->rq_disk->private_data; |
1319 | if (unlikely(!drv->init_command(cmd))) { | |
1320 | scsi_release_buffers(cmd); | |
1321 | scsi_put_command(cmd); | |
6f16b535 | 1322 | goto kill; |
e537a36d | 1323 | } |
1da177e4 LT |
1324 | } |
1325 | } | |
1326 | ||
1327 | /* | |
1328 | * The request is now prepped, no need to come back here | |
1329 | */ | |
1330 | req->flags |= REQ_DONTPREP; | |
1331 | return BLKPREP_OK; | |
1332 | ||
1333 | defer: | |
1334 | /* If we defer, the elv_next_request() returns NULL, but the | |
1335 | * queue must be restarted, so we plug here if no returning | |
1336 | * command will automatically do that. */ | |
1337 | if (sdev->device_busy == 0) | |
1338 | blk_plug_device(q); | |
1339 | return BLKPREP_DEFER; | |
6f16b535 MC |
1340 | kill: |
1341 | req->errors = DID_NO_CONNECT << 16; | |
1342 | return BLKPREP_KILL; | |
1da177e4 LT |
1343 | } |
1344 | ||
1345 | /* | |
1346 | * scsi_dev_queue_ready: if we can send requests to sdev, return 1 else | |
1347 | * return 0. | |
1348 | * | |
1349 | * Called with the queue_lock held. | |
1350 | */ | |
1351 | static inline int scsi_dev_queue_ready(struct request_queue *q, | |
1352 | struct scsi_device *sdev) | |
1353 | { | |
1354 | if (sdev->device_busy >= sdev->queue_depth) | |
1355 | return 0; | |
1356 | if (sdev->device_busy == 0 && sdev->device_blocked) { | |
1357 | /* | |
1358 | * unblock after device_blocked iterates to zero | |
1359 | */ | |
1360 | if (--sdev->device_blocked == 0) { | |
1361 | SCSI_LOG_MLQUEUE(3, | |
9ccfc756 JB |
1362 | sdev_printk(KERN_INFO, sdev, |
1363 | "unblocking device at zero depth\n")); | |
1da177e4 LT |
1364 | } else { |
1365 | blk_plug_device(q); | |
1366 | return 0; | |
1367 | } | |
1368 | } | |
1369 | if (sdev->device_blocked) | |
1370 | return 0; | |
1371 | ||
1372 | return 1; | |
1373 | } | |
1374 | ||
1375 | /* | |
1376 | * scsi_host_queue_ready: if we can send requests to shost, return 1 else | |
1377 | * return 0. We must end up running the queue again whenever 0 is | |
1378 | * returned, else IO can hang. | |
1379 | * | |
1380 | * Called with host_lock held. | |
1381 | */ | |
1382 | static inline int scsi_host_queue_ready(struct request_queue *q, | |
1383 | struct Scsi_Host *shost, | |
1384 | struct scsi_device *sdev) | |
1385 | { | |
939647ee | 1386 | if (scsi_host_in_recovery(shost)) |
1da177e4 LT |
1387 | return 0; |
1388 | if (shost->host_busy == 0 && shost->host_blocked) { | |
1389 | /* | |
1390 | * unblock after host_blocked iterates to zero | |
1391 | */ | |
1392 | if (--shost->host_blocked == 0) { | |
1393 | SCSI_LOG_MLQUEUE(3, | |
1394 | printk("scsi%d unblocking host at zero depth\n", | |
1395 | shost->host_no)); | |
1396 | } else { | |
1397 | blk_plug_device(q); | |
1398 | return 0; | |
1399 | } | |
1400 | } | |
1401 | if ((shost->can_queue > 0 && shost->host_busy >= shost->can_queue) || | |
1402 | shost->host_blocked || shost->host_self_blocked) { | |
1403 | if (list_empty(&sdev->starved_entry)) | |
1404 | list_add_tail(&sdev->starved_entry, &shost->starved_list); | |
1405 | return 0; | |
1406 | } | |
1407 | ||
1408 | /* We're OK to process the command, so we can't be starved */ | |
1409 | if (!list_empty(&sdev->starved_entry)) | |
1410 | list_del_init(&sdev->starved_entry); | |
1411 | ||
1412 | return 1; | |
1413 | } | |
1414 | ||
1415 | /* | |
e91442b6 | 1416 | * Kill a request for a dead device |
1da177e4 | 1417 | */ |
e91442b6 | 1418 | static void scsi_kill_request(struct request *req, request_queue_t *q) |
1da177e4 | 1419 | { |
e91442b6 | 1420 | struct scsi_cmnd *cmd = req->special; |
e36e0c80 TH |
1421 | struct scsi_device *sdev = cmd->device; |
1422 | struct Scsi_Host *shost = sdev->host; | |
1da177e4 | 1423 | |
788ce43a JB |
1424 | blkdev_dequeue_request(req); |
1425 | ||
e91442b6 JB |
1426 | if (unlikely(cmd == NULL)) { |
1427 | printk(KERN_CRIT "impossible request in %s.\n", | |
1428 | __FUNCTION__); | |
1429 | BUG(); | |
1da177e4 | 1430 | } |
e91442b6 JB |
1431 | |
1432 | scsi_init_cmd_errh(cmd); | |
1433 | cmd->result = DID_NO_CONNECT << 16; | |
1434 | atomic_inc(&cmd->device->iorequest_cnt); | |
e36e0c80 TH |
1435 | |
1436 | /* | |
1437 | * SCSI request completion path will do scsi_device_unbusy(), | |
1438 | * bump busy counts. To bump the counters, we need to dance | |
1439 | * with the locks as normal issue path does. | |
1440 | */ | |
1441 | sdev->device_busy++; | |
1442 | spin_unlock(sdev->request_queue->queue_lock); | |
1443 | spin_lock(shost->host_lock); | |
1444 | shost->host_busy++; | |
1445 | spin_unlock(shost->host_lock); | |
1446 | spin_lock(sdev->request_queue->queue_lock); | |
1447 | ||
e91442b6 | 1448 | __scsi_done(cmd); |
1da177e4 LT |
1449 | } |
1450 | ||
1aea6434 JA |
1451 | static void scsi_softirq_done(struct request *rq) |
1452 | { | |
1453 | struct scsi_cmnd *cmd = rq->completion_data; | |
8884efab | 1454 | unsigned long wait_for = (cmd->allowed + 1) * cmd->timeout_per_command; |
1aea6434 JA |
1455 | int disposition; |
1456 | ||
1457 | INIT_LIST_HEAD(&cmd->eh_entry); | |
1458 | ||
1459 | disposition = scsi_decide_disposition(cmd); | |
1460 | if (disposition != SUCCESS && | |
1461 | time_before(cmd->jiffies_at_alloc + wait_for, jiffies)) { | |
1462 | sdev_printk(KERN_ERR, cmd->device, | |
1463 | "timing out command, waited %lus\n", | |
1464 | wait_for/HZ); | |
1465 | disposition = SUCCESS; | |
1466 | } | |
1467 | ||
1468 | scsi_log_completion(cmd, disposition); | |
1469 | ||
1470 | switch (disposition) { | |
1471 | case SUCCESS: | |
1472 | scsi_finish_command(cmd); | |
1473 | break; | |
1474 | case NEEDS_RETRY: | |
1475 | scsi_retry_command(cmd); | |
1476 | break; | |
1477 | case ADD_TO_MLQUEUE: | |
1478 | scsi_queue_insert(cmd, SCSI_MLQUEUE_DEVICE_BUSY); | |
1479 | break; | |
1480 | default: | |
1481 | if (!scsi_eh_scmd_add(cmd, 0)) | |
1482 | scsi_finish_command(cmd); | |
1483 | } | |
1484 | } | |
1485 | ||
1da177e4 LT |
1486 | /* |
1487 | * Function: scsi_request_fn() | |
1488 | * | |
1489 | * Purpose: Main strategy routine for SCSI. | |
1490 | * | |
1491 | * Arguments: q - Pointer to actual queue. | |
1492 | * | |
1493 | * Returns: Nothing | |
1494 | * | |
1495 | * Lock status: IO request lock assumed to be held when called. | |
1496 | */ | |
1497 | static void scsi_request_fn(struct request_queue *q) | |
1498 | { | |
1499 | struct scsi_device *sdev = q->queuedata; | |
1500 | struct Scsi_Host *shost; | |
1501 | struct scsi_cmnd *cmd; | |
1502 | struct request *req; | |
1503 | ||
1504 | if (!sdev) { | |
1505 | printk("scsi: killing requests for dead queue\n"); | |
e91442b6 JB |
1506 | while ((req = elv_next_request(q)) != NULL) |
1507 | scsi_kill_request(req, q); | |
1da177e4 LT |
1508 | return; |
1509 | } | |
1510 | ||
1511 | if(!get_device(&sdev->sdev_gendev)) | |
1512 | /* We must be tearing the block queue down already */ | |
1513 | return; | |
1514 | ||
1515 | /* | |
1516 | * To start with, we keep looping until the queue is empty, or until | |
1517 | * the host is no longer able to accept any more requests. | |
1518 | */ | |
1519 | shost = sdev->host; | |
1520 | while (!blk_queue_plugged(q)) { | |
1521 | int rtn; | |
1522 | /* | |
1523 | * get next queueable request. We do this early to make sure | |
1524 | * that the request is fully prepared even if we cannot | |
1525 | * accept it. | |
1526 | */ | |
1527 | req = elv_next_request(q); | |
1528 | if (!req || !scsi_dev_queue_ready(q, sdev)) | |
1529 | break; | |
1530 | ||
1531 | if (unlikely(!scsi_device_online(sdev))) { | |
9ccfc756 JB |
1532 | sdev_printk(KERN_ERR, sdev, |
1533 | "rejecting I/O to offline device\n"); | |
e91442b6 | 1534 | scsi_kill_request(req, q); |
1da177e4 LT |
1535 | continue; |
1536 | } | |
1537 | ||
1538 | ||
1539 | /* | |
1540 | * Remove the request from the request list. | |
1541 | */ | |
1542 | if (!(blk_queue_tagged(q) && !blk_queue_start_tag(q, req))) | |
1543 | blkdev_dequeue_request(req); | |
1544 | sdev->device_busy++; | |
1545 | ||
1546 | spin_unlock(q->queue_lock); | |
e91442b6 JB |
1547 | cmd = req->special; |
1548 | if (unlikely(cmd == NULL)) { | |
1549 | printk(KERN_CRIT "impossible request in %s.\n" | |
1550 | "please mail a stack trace to " | |
1551 | "linux-scsi@vger.kernel.org", | |
1552 | __FUNCTION__); | |
1553 | BUG(); | |
1554 | } | |
1da177e4 LT |
1555 | spin_lock(shost->host_lock); |
1556 | ||
1557 | if (!scsi_host_queue_ready(q, shost, sdev)) | |
1558 | goto not_ready; | |
1559 | if (sdev->single_lun) { | |
1560 | if (scsi_target(sdev)->starget_sdev_user && | |
1561 | scsi_target(sdev)->starget_sdev_user != sdev) | |
1562 | goto not_ready; | |
1563 | scsi_target(sdev)->starget_sdev_user = sdev; | |
1564 | } | |
1565 | shost->host_busy++; | |
1566 | ||
1567 | /* | |
1568 | * XXX(hch): This is rather suboptimal, scsi_dispatch_cmd will | |
1569 | * take the lock again. | |
1570 | */ | |
1571 | spin_unlock_irq(shost->host_lock); | |
1572 | ||
1da177e4 LT |
1573 | /* |
1574 | * Finally, initialize any error handling parameters, and set up | |
1575 | * the timers for timeouts. | |
1576 | */ | |
1577 | scsi_init_cmd_errh(cmd); | |
1578 | ||
1579 | /* | |
1580 | * Dispatch the command to the low-level driver. | |
1581 | */ | |
1582 | rtn = scsi_dispatch_cmd(cmd); | |
1583 | spin_lock_irq(q->queue_lock); | |
1584 | if(rtn) { | |
1585 | /* we're refusing the command; because of | |
1586 | * the way locks get dropped, we need to | |
1587 | * check here if plugging is required */ | |
1588 | if(sdev->device_busy == 0) | |
1589 | blk_plug_device(q); | |
1590 | ||
1591 | break; | |
1592 | } | |
1593 | } | |
1594 | ||
1595 | goto out; | |
1596 | ||
1597 | not_ready: | |
1598 | spin_unlock_irq(shost->host_lock); | |
1599 | ||
1600 | /* | |
1601 | * lock q, handle tag, requeue req, and decrement device_busy. We | |
1602 | * must return with queue_lock held. | |
1603 | * | |
1604 | * Decrementing device_busy without checking it is OK, as all such | |
1605 | * cases (host limits or settings) should run the queue at some | |
1606 | * later time. | |
1607 | */ | |
1608 | spin_lock_irq(q->queue_lock); | |
1609 | blk_requeue_request(q, req); | |
1610 | sdev->device_busy--; | |
1611 | if(sdev->device_busy == 0) | |
1612 | blk_plug_device(q); | |
1613 | out: | |
1614 | /* must be careful here...if we trigger the ->remove() function | |
1615 | * we cannot be holding the q lock */ | |
1616 | spin_unlock_irq(q->queue_lock); | |
1617 | put_device(&sdev->sdev_gendev); | |
1618 | spin_lock_irq(q->queue_lock); | |
1619 | } | |
1620 | ||
1621 | u64 scsi_calculate_bounce_limit(struct Scsi_Host *shost) | |
1622 | { | |
1623 | struct device *host_dev; | |
1624 | u64 bounce_limit = 0xffffffff; | |
1625 | ||
1626 | if (shost->unchecked_isa_dma) | |
1627 | return BLK_BOUNCE_ISA; | |
1628 | /* | |
1629 | * Platforms with virtual-DMA translation | |
1630 | * hardware have no practical limit. | |
1631 | */ | |
1632 | if (!PCI_DMA_BUS_IS_PHYS) | |
1633 | return BLK_BOUNCE_ANY; | |
1634 | ||
1635 | host_dev = scsi_get_device(shost); | |
1636 | if (host_dev && host_dev->dma_mask) | |
1637 | bounce_limit = *host_dev->dma_mask; | |
1638 | ||
1639 | return bounce_limit; | |
1640 | } | |
1641 | EXPORT_SYMBOL(scsi_calculate_bounce_limit); | |
1642 | ||
1643 | struct request_queue *scsi_alloc_queue(struct scsi_device *sdev) | |
1644 | { | |
1645 | struct Scsi_Host *shost = sdev->host; | |
1646 | struct request_queue *q; | |
1647 | ||
152587de | 1648 | q = blk_init_queue(scsi_request_fn, NULL); |
1da177e4 LT |
1649 | if (!q) |
1650 | return NULL; | |
1651 | ||
1652 | blk_queue_prep_rq(q, scsi_prep_fn); | |
1653 | ||
1654 | blk_queue_max_hw_segments(q, shost->sg_tablesize); | |
1655 | blk_queue_max_phys_segments(q, SCSI_MAX_PHYS_SEGMENTS); | |
1656 | blk_queue_max_sectors(q, shost->max_sectors); | |
1657 | blk_queue_bounce_limit(q, scsi_calculate_bounce_limit(shost)); | |
1658 | blk_queue_segment_boundary(q, shost->dma_boundary); | |
1659 | blk_queue_issue_flush_fn(q, scsi_issue_flush_fn); | |
1aea6434 | 1660 | blk_queue_softirq_done(q, scsi_softirq_done); |
1da177e4 | 1661 | |
1da177e4 LT |
1662 | if (!shost->use_clustering) |
1663 | clear_bit(QUEUE_FLAG_CLUSTER, &q->queue_flags); | |
1664 | return q; | |
1665 | } | |
1666 | ||
1667 | void scsi_free_queue(struct request_queue *q) | |
1668 | { | |
1669 | blk_cleanup_queue(q); | |
1670 | } | |
1671 | ||
1672 | /* | |
1673 | * Function: scsi_block_requests() | |
1674 | * | |
1675 | * Purpose: Utility function used by low-level drivers to prevent further | |
1676 | * commands from being queued to the device. | |
1677 | * | |
1678 | * Arguments: shost - Host in question | |
1679 | * | |
1680 | * Returns: Nothing | |
1681 | * | |
1682 | * Lock status: No locks are assumed held. | |
1683 | * | |
1684 | * Notes: There is no timer nor any other means by which the requests | |
1685 | * get unblocked other than the low-level driver calling | |
1686 | * scsi_unblock_requests(). | |
1687 | */ | |
1688 | void scsi_block_requests(struct Scsi_Host *shost) | |
1689 | { | |
1690 | shost->host_self_blocked = 1; | |
1691 | } | |
1692 | EXPORT_SYMBOL(scsi_block_requests); | |
1693 | ||
1694 | /* | |
1695 | * Function: scsi_unblock_requests() | |
1696 | * | |
1697 | * Purpose: Utility function used by low-level drivers to allow further | |
1698 | * commands from being queued to the device. | |
1699 | * | |
1700 | * Arguments: shost - Host in question | |
1701 | * | |
1702 | * Returns: Nothing | |
1703 | * | |
1704 | * Lock status: No locks are assumed held. | |
1705 | * | |
1706 | * Notes: There is no timer nor any other means by which the requests | |
1707 | * get unblocked other than the low-level driver calling | |
1708 | * scsi_unblock_requests(). | |
1709 | * | |
1710 | * This is done as an API function so that changes to the | |
1711 | * internals of the scsi mid-layer won't require wholesale | |
1712 | * changes to drivers that use this feature. | |
1713 | */ | |
1714 | void scsi_unblock_requests(struct Scsi_Host *shost) | |
1715 | { | |
1716 | shost->host_self_blocked = 0; | |
1717 | scsi_run_host_queues(shost); | |
1718 | } | |
1719 | EXPORT_SYMBOL(scsi_unblock_requests); | |
1720 | ||
1721 | int __init scsi_init_queue(void) | |
1722 | { | |
1723 | int i; | |
1724 | ||
aa7b5cd7 MC |
1725 | scsi_io_context_cache = kmem_cache_create("scsi_io_context", |
1726 | sizeof(struct scsi_io_context), | |
1727 | 0, 0, NULL, NULL); | |
1728 | if (!scsi_io_context_cache) { | |
1729 | printk(KERN_ERR "SCSI: can't init scsi io context cache\n"); | |
1730 | return -ENOMEM; | |
1731 | } | |
1732 | ||
1da177e4 LT |
1733 | for (i = 0; i < SG_MEMPOOL_NR; i++) { |
1734 | struct scsi_host_sg_pool *sgp = scsi_sg_pools + i; | |
1735 | int size = sgp->size * sizeof(struct scatterlist); | |
1736 | ||
1737 | sgp->slab = kmem_cache_create(sgp->name, size, 0, | |
1738 | SLAB_HWCACHE_ALIGN, NULL, NULL); | |
1739 | if (!sgp->slab) { | |
1740 | printk(KERN_ERR "SCSI: can't init sg slab %s\n", | |
1741 | sgp->name); | |
1742 | } | |
1743 | ||
93d2341c MD |
1744 | sgp->pool = mempool_create_slab_pool(SG_MEMPOOL_SIZE, |
1745 | sgp->slab); | |
1da177e4 LT |
1746 | if (!sgp->pool) { |
1747 | printk(KERN_ERR "SCSI: can't init sg mempool %s\n", | |
1748 | sgp->name); | |
1749 | } | |
1750 | } | |
1751 | ||
1752 | return 0; | |
1753 | } | |
1754 | ||
1755 | void scsi_exit_queue(void) | |
1756 | { | |
1757 | int i; | |
1758 | ||
aa7b5cd7 MC |
1759 | kmem_cache_destroy(scsi_io_context_cache); |
1760 | ||
1da177e4 LT |
1761 | for (i = 0; i < SG_MEMPOOL_NR; i++) { |
1762 | struct scsi_host_sg_pool *sgp = scsi_sg_pools + i; | |
1763 | mempool_destroy(sgp->pool); | |
1764 | kmem_cache_destroy(sgp->slab); | |
1765 | } | |
1766 | } | |
5baba830 JB |
1767 | |
1768 | /** | |
1769 | * scsi_mode_select - issue a mode select | |
1770 | * @sdev: SCSI device to be queried | |
1771 | * @pf: Page format bit (1 == standard, 0 == vendor specific) | |
1772 | * @sp: Save page bit (0 == don't save, 1 == save) | |
1773 | * @modepage: mode page being requested | |
1774 | * @buffer: request buffer (may not be smaller than eight bytes) | |
1775 | * @len: length of request buffer. | |
1776 | * @timeout: command timeout | |
1777 | * @retries: number of retries before failing | |
1778 | * @data: returns a structure abstracting the mode header data | |
1779 | * @sense: place to put sense data (or NULL if no sense to be collected). | |
1780 | * must be SCSI_SENSE_BUFFERSIZE big. | |
1781 | * | |
1782 | * Returns zero if successful; negative error number or scsi | |
1783 | * status on error | |
1784 | * | |
1785 | */ | |
1786 | int | |
1787 | scsi_mode_select(struct scsi_device *sdev, int pf, int sp, int modepage, | |
1788 | unsigned char *buffer, int len, int timeout, int retries, | |
1789 | struct scsi_mode_data *data, struct scsi_sense_hdr *sshdr) | |
1790 | { | |
1791 | unsigned char cmd[10]; | |
1792 | unsigned char *real_buffer; | |
1793 | int ret; | |
1794 | ||
1795 | memset(cmd, 0, sizeof(cmd)); | |
1796 | cmd[1] = (pf ? 0x10 : 0) | (sp ? 0x01 : 0); | |
1797 | ||
1798 | if (sdev->use_10_for_ms) { | |
1799 | if (len > 65535) | |
1800 | return -EINVAL; | |
1801 | real_buffer = kmalloc(8 + len, GFP_KERNEL); | |
1802 | if (!real_buffer) | |
1803 | return -ENOMEM; | |
1804 | memcpy(real_buffer + 8, buffer, len); | |
1805 | len += 8; | |
1806 | real_buffer[0] = 0; | |
1807 | real_buffer[1] = 0; | |
1808 | real_buffer[2] = data->medium_type; | |
1809 | real_buffer[3] = data->device_specific; | |
1810 | real_buffer[4] = data->longlba ? 0x01 : 0; | |
1811 | real_buffer[5] = 0; | |
1812 | real_buffer[6] = data->block_descriptor_length >> 8; | |
1813 | real_buffer[7] = data->block_descriptor_length; | |
1814 | ||
1815 | cmd[0] = MODE_SELECT_10; | |
1816 | cmd[7] = len >> 8; | |
1817 | cmd[8] = len; | |
1818 | } else { | |
1819 | if (len > 255 || data->block_descriptor_length > 255 || | |
1820 | data->longlba) | |
1821 | return -EINVAL; | |
1822 | ||
1823 | real_buffer = kmalloc(4 + len, GFP_KERNEL); | |
1824 | if (!real_buffer) | |
1825 | return -ENOMEM; | |
1826 | memcpy(real_buffer + 4, buffer, len); | |
1827 | len += 4; | |
1828 | real_buffer[0] = 0; | |
1829 | real_buffer[1] = data->medium_type; | |
1830 | real_buffer[2] = data->device_specific; | |
1831 | real_buffer[3] = data->block_descriptor_length; | |
1832 | ||
1833 | ||
1834 | cmd[0] = MODE_SELECT; | |
1835 | cmd[4] = len; | |
1836 | } | |
1837 | ||
1838 | ret = scsi_execute_req(sdev, cmd, DMA_TO_DEVICE, real_buffer, len, | |
1839 | sshdr, timeout, retries); | |
1840 | kfree(real_buffer); | |
1841 | return ret; | |
1842 | } | |
1843 | EXPORT_SYMBOL_GPL(scsi_mode_select); | |
1844 | ||
1da177e4 | 1845 | /** |
ea73a9f2 | 1846 | * scsi_mode_sense - issue a mode sense, falling back from 10 to |
1da177e4 | 1847 | * six bytes if necessary. |
1cf72699 | 1848 | * @sdev: SCSI device to be queried |
1da177e4 LT |
1849 | * @dbd: set if mode sense will allow block descriptors to be returned |
1850 | * @modepage: mode page being requested | |
1851 | * @buffer: request buffer (may not be smaller than eight bytes) | |
1852 | * @len: length of request buffer. | |
1853 | * @timeout: command timeout | |
1854 | * @retries: number of retries before failing | |
1855 | * @data: returns a structure abstracting the mode header data | |
1cf72699 JB |
1856 | * @sense: place to put sense data (or NULL if no sense to be collected). |
1857 | * must be SCSI_SENSE_BUFFERSIZE big. | |
1da177e4 LT |
1858 | * |
1859 | * Returns zero if unsuccessful, or the header offset (either 4 | |
1860 | * or 8 depending on whether a six or ten byte command was | |
1861 | * issued) if successful. | |
1862 | **/ | |
1863 | int | |
1cf72699 | 1864 | scsi_mode_sense(struct scsi_device *sdev, int dbd, int modepage, |
1da177e4 | 1865 | unsigned char *buffer, int len, int timeout, int retries, |
5baba830 JB |
1866 | struct scsi_mode_data *data, struct scsi_sense_hdr *sshdr) |
1867 | { | |
1da177e4 LT |
1868 | unsigned char cmd[12]; |
1869 | int use_10_for_ms; | |
1870 | int header_length; | |
1cf72699 | 1871 | int result; |
ea73a9f2 | 1872 | struct scsi_sense_hdr my_sshdr; |
1da177e4 LT |
1873 | |
1874 | memset(data, 0, sizeof(*data)); | |
1875 | memset(&cmd[0], 0, 12); | |
1876 | cmd[1] = dbd & 0x18; /* allows DBD and LLBA bits */ | |
1877 | cmd[2] = modepage; | |
1878 | ||
ea73a9f2 JB |
1879 | /* caller might not be interested in sense, but we need it */ |
1880 | if (!sshdr) | |
1881 | sshdr = &my_sshdr; | |
1882 | ||
1da177e4 | 1883 | retry: |
1cf72699 | 1884 | use_10_for_ms = sdev->use_10_for_ms; |
1da177e4 LT |
1885 | |
1886 | if (use_10_for_ms) { | |
1887 | if (len < 8) | |
1888 | len = 8; | |
1889 | ||
1890 | cmd[0] = MODE_SENSE_10; | |
1891 | cmd[8] = len; | |
1892 | header_length = 8; | |
1893 | } else { | |
1894 | if (len < 4) | |
1895 | len = 4; | |
1896 | ||
1897 | cmd[0] = MODE_SENSE; | |
1898 | cmd[4] = len; | |
1899 | header_length = 4; | |
1900 | } | |
1901 | ||
1da177e4 LT |
1902 | memset(buffer, 0, len); |
1903 | ||
1cf72699 | 1904 | result = scsi_execute_req(sdev, cmd, DMA_FROM_DEVICE, buffer, len, |
ea73a9f2 | 1905 | sshdr, timeout, retries); |
1da177e4 LT |
1906 | |
1907 | /* This code looks awful: what it's doing is making sure an | |
1908 | * ILLEGAL REQUEST sense return identifies the actual command | |
1909 | * byte as the problem. MODE_SENSE commands can return | |
1910 | * ILLEGAL REQUEST if the code page isn't supported */ | |
1911 | ||
1cf72699 JB |
1912 | if (use_10_for_ms && !scsi_status_is_good(result) && |
1913 | (driver_byte(result) & DRIVER_SENSE)) { | |
ea73a9f2 JB |
1914 | if (scsi_sense_valid(sshdr)) { |
1915 | if ((sshdr->sense_key == ILLEGAL_REQUEST) && | |
1916 | (sshdr->asc == 0x20) && (sshdr->ascq == 0)) { | |
1da177e4 LT |
1917 | /* |
1918 | * Invalid command operation code | |
1919 | */ | |
1cf72699 | 1920 | sdev->use_10_for_ms = 0; |
1da177e4 LT |
1921 | goto retry; |
1922 | } | |
1923 | } | |
1924 | } | |
1925 | ||
1cf72699 | 1926 | if(scsi_status_is_good(result)) { |
6d73c851 AV |
1927 | if (unlikely(buffer[0] == 0x86 && buffer[1] == 0x0b && |
1928 | (modepage == 6 || modepage == 8))) { | |
1929 | /* Initio breakage? */ | |
1930 | header_length = 0; | |
1931 | data->length = 13; | |
1932 | data->medium_type = 0; | |
1933 | data->device_specific = 0; | |
1934 | data->longlba = 0; | |
1935 | data->block_descriptor_length = 0; | |
1936 | } else if(use_10_for_ms) { | |
1da177e4 LT |
1937 | data->length = buffer[0]*256 + buffer[1] + 2; |
1938 | data->medium_type = buffer[2]; | |
1939 | data->device_specific = buffer[3]; | |
1940 | data->longlba = buffer[4] & 0x01; | |
1941 | data->block_descriptor_length = buffer[6]*256 | |
1942 | + buffer[7]; | |
1943 | } else { | |
1944 | data->length = buffer[0] + 1; | |
1945 | data->medium_type = buffer[1]; | |
1946 | data->device_specific = buffer[2]; | |
1947 | data->block_descriptor_length = buffer[3]; | |
1948 | } | |
6d73c851 | 1949 | data->header_length = header_length; |
1da177e4 LT |
1950 | } |
1951 | ||
1cf72699 | 1952 | return result; |
1da177e4 LT |
1953 | } |
1954 | EXPORT_SYMBOL(scsi_mode_sense); | |
1955 | ||
1956 | int | |
1957 | scsi_test_unit_ready(struct scsi_device *sdev, int timeout, int retries) | |
1958 | { | |
1da177e4 LT |
1959 | char cmd[] = { |
1960 | TEST_UNIT_READY, 0, 0, 0, 0, 0, | |
1961 | }; | |
ea73a9f2 | 1962 | struct scsi_sense_hdr sshdr; |
1da177e4 LT |
1963 | int result; |
1964 | ||
ea73a9f2 | 1965 | result = scsi_execute_req(sdev, cmd, DMA_NONE, NULL, 0, &sshdr, |
1cf72699 | 1966 | timeout, retries); |
1da177e4 | 1967 | |
1cf72699 | 1968 | if ((driver_byte(result) & DRIVER_SENSE) && sdev->removable) { |
1da177e4 | 1969 | |
ea73a9f2 | 1970 | if ((scsi_sense_valid(&sshdr)) && |
1da177e4 LT |
1971 | ((sshdr.sense_key == UNIT_ATTENTION) || |
1972 | (sshdr.sense_key == NOT_READY))) { | |
1973 | sdev->changed = 1; | |
1cf72699 | 1974 | result = 0; |
1da177e4 LT |
1975 | } |
1976 | } | |
1da177e4 LT |
1977 | return result; |
1978 | } | |
1979 | EXPORT_SYMBOL(scsi_test_unit_ready); | |
1980 | ||
1981 | /** | |
1982 | * scsi_device_set_state - Take the given device through the device | |
1983 | * state model. | |
1984 | * @sdev: scsi device to change the state of. | |
1985 | * @state: state to change to. | |
1986 | * | |
1987 | * Returns zero if unsuccessful or an error if the requested | |
1988 | * transition is illegal. | |
1989 | **/ | |
1990 | int | |
1991 | scsi_device_set_state(struct scsi_device *sdev, enum scsi_device_state state) | |
1992 | { | |
1993 | enum scsi_device_state oldstate = sdev->sdev_state; | |
1994 | ||
1995 | if (state == oldstate) | |
1996 | return 0; | |
1997 | ||
1998 | switch (state) { | |
1999 | case SDEV_CREATED: | |
2000 | /* There are no legal states that come back to | |
2001 | * created. This is the manually initialised start | |
2002 | * state */ | |
2003 | goto illegal; | |
2004 | ||
2005 | case SDEV_RUNNING: | |
2006 | switch (oldstate) { | |
2007 | case SDEV_CREATED: | |
2008 | case SDEV_OFFLINE: | |
2009 | case SDEV_QUIESCE: | |
2010 | case SDEV_BLOCK: | |
2011 | break; | |
2012 | default: | |
2013 | goto illegal; | |
2014 | } | |
2015 | break; | |
2016 | ||
2017 | case SDEV_QUIESCE: | |
2018 | switch (oldstate) { | |
2019 | case SDEV_RUNNING: | |
2020 | case SDEV_OFFLINE: | |
2021 | break; | |
2022 | default: | |
2023 | goto illegal; | |
2024 | } | |
2025 | break; | |
2026 | ||
2027 | case SDEV_OFFLINE: | |
2028 | switch (oldstate) { | |
2029 | case SDEV_CREATED: | |
2030 | case SDEV_RUNNING: | |
2031 | case SDEV_QUIESCE: | |
2032 | case SDEV_BLOCK: | |
2033 | break; | |
2034 | default: | |
2035 | goto illegal; | |
2036 | } | |
2037 | break; | |
2038 | ||
2039 | case SDEV_BLOCK: | |
2040 | switch (oldstate) { | |
2041 | case SDEV_CREATED: | |
2042 | case SDEV_RUNNING: | |
2043 | break; | |
2044 | default: | |
2045 | goto illegal; | |
2046 | } | |
2047 | break; | |
2048 | ||
2049 | case SDEV_CANCEL: | |
2050 | switch (oldstate) { | |
2051 | case SDEV_CREATED: | |
2052 | case SDEV_RUNNING: | |
2053 | case SDEV_OFFLINE: | |
2054 | case SDEV_BLOCK: | |
2055 | break; | |
2056 | default: | |
2057 | goto illegal; | |
2058 | } | |
2059 | break; | |
2060 | ||
2061 | case SDEV_DEL: | |
2062 | switch (oldstate) { | |
2063 | case SDEV_CANCEL: | |
2064 | break; | |
2065 | default: | |
2066 | goto illegal; | |
2067 | } | |
2068 | break; | |
2069 | ||
2070 | } | |
2071 | sdev->sdev_state = state; | |
2072 | return 0; | |
2073 | ||
2074 | illegal: | |
2075 | SCSI_LOG_ERROR_RECOVERY(1, | |
9ccfc756 JB |
2076 | sdev_printk(KERN_ERR, sdev, |
2077 | "Illegal state transition %s->%s\n", | |
2078 | scsi_device_state_name(oldstate), | |
2079 | scsi_device_state_name(state)) | |
1da177e4 LT |
2080 | ); |
2081 | return -EINVAL; | |
2082 | } | |
2083 | EXPORT_SYMBOL(scsi_device_set_state); | |
2084 | ||
2085 | /** | |
2086 | * scsi_device_quiesce - Block user issued commands. | |
2087 | * @sdev: scsi device to quiesce. | |
2088 | * | |
2089 | * This works by trying to transition to the SDEV_QUIESCE state | |
2090 | * (which must be a legal transition). When the device is in this | |
2091 | * state, only special requests will be accepted, all others will | |
2092 | * be deferred. Since special requests may also be requeued requests, | |
2093 | * a successful return doesn't guarantee the device will be | |
2094 | * totally quiescent. | |
2095 | * | |
2096 | * Must be called with user context, may sleep. | |
2097 | * | |
2098 | * Returns zero if unsuccessful or an error if not. | |
2099 | **/ | |
2100 | int | |
2101 | scsi_device_quiesce(struct scsi_device *sdev) | |
2102 | { | |
2103 | int err = scsi_device_set_state(sdev, SDEV_QUIESCE); | |
2104 | if (err) | |
2105 | return err; | |
2106 | ||
2107 | scsi_run_queue(sdev->request_queue); | |
2108 | while (sdev->device_busy) { | |
2109 | msleep_interruptible(200); | |
2110 | scsi_run_queue(sdev->request_queue); | |
2111 | } | |
2112 | return 0; | |
2113 | } | |
2114 | EXPORT_SYMBOL(scsi_device_quiesce); | |
2115 | ||
2116 | /** | |
2117 | * scsi_device_resume - Restart user issued commands to a quiesced device. | |
2118 | * @sdev: scsi device to resume. | |
2119 | * | |
2120 | * Moves the device from quiesced back to running and restarts the | |
2121 | * queues. | |
2122 | * | |
2123 | * Must be called with user context, may sleep. | |
2124 | **/ | |
2125 | void | |
2126 | scsi_device_resume(struct scsi_device *sdev) | |
2127 | { | |
2128 | if(scsi_device_set_state(sdev, SDEV_RUNNING)) | |
2129 | return; | |
2130 | scsi_run_queue(sdev->request_queue); | |
2131 | } | |
2132 | EXPORT_SYMBOL(scsi_device_resume); | |
2133 | ||
2134 | static void | |
2135 | device_quiesce_fn(struct scsi_device *sdev, void *data) | |
2136 | { | |
2137 | scsi_device_quiesce(sdev); | |
2138 | } | |
2139 | ||
2140 | void | |
2141 | scsi_target_quiesce(struct scsi_target *starget) | |
2142 | { | |
2143 | starget_for_each_device(starget, NULL, device_quiesce_fn); | |
2144 | } | |
2145 | EXPORT_SYMBOL(scsi_target_quiesce); | |
2146 | ||
2147 | static void | |
2148 | device_resume_fn(struct scsi_device *sdev, void *data) | |
2149 | { | |
2150 | scsi_device_resume(sdev); | |
2151 | } | |
2152 | ||
2153 | void | |
2154 | scsi_target_resume(struct scsi_target *starget) | |
2155 | { | |
2156 | starget_for_each_device(starget, NULL, device_resume_fn); | |
2157 | } | |
2158 | EXPORT_SYMBOL(scsi_target_resume); | |
2159 | ||
2160 | /** | |
2161 | * scsi_internal_device_block - internal function to put a device | |
2162 | * temporarily into the SDEV_BLOCK state | |
2163 | * @sdev: device to block | |
2164 | * | |
2165 | * Block request made by scsi lld's to temporarily stop all | |
2166 | * scsi commands on the specified device. Called from interrupt | |
2167 | * or normal process context. | |
2168 | * | |
2169 | * Returns zero if successful or error if not | |
2170 | * | |
2171 | * Notes: | |
2172 | * This routine transitions the device to the SDEV_BLOCK state | |
2173 | * (which must be a legal transition). When the device is in this | |
2174 | * state, all commands are deferred until the scsi lld reenables | |
2175 | * the device with scsi_device_unblock or device_block_tmo fires. | |
2176 | * This routine assumes the host_lock is held on entry. | |
2177 | **/ | |
2178 | int | |
2179 | scsi_internal_device_block(struct scsi_device *sdev) | |
2180 | { | |
2181 | request_queue_t *q = sdev->request_queue; | |
2182 | unsigned long flags; | |
2183 | int err = 0; | |
2184 | ||
2185 | err = scsi_device_set_state(sdev, SDEV_BLOCK); | |
2186 | if (err) | |
2187 | return err; | |
2188 | ||
2189 | /* | |
2190 | * The device has transitioned to SDEV_BLOCK. Stop the | |
2191 | * block layer from calling the midlayer with this device's | |
2192 | * request queue. | |
2193 | */ | |
2194 | spin_lock_irqsave(q->queue_lock, flags); | |
2195 | blk_stop_queue(q); | |
2196 | spin_unlock_irqrestore(q->queue_lock, flags); | |
2197 | ||
2198 | return 0; | |
2199 | } | |
2200 | EXPORT_SYMBOL_GPL(scsi_internal_device_block); | |
2201 | ||
2202 | /** | |
2203 | * scsi_internal_device_unblock - resume a device after a block request | |
2204 | * @sdev: device to resume | |
2205 | * | |
2206 | * Called by scsi lld's or the midlayer to restart the device queue | |
2207 | * for the previously suspended scsi device. Called from interrupt or | |
2208 | * normal process context. | |
2209 | * | |
2210 | * Returns zero if successful or error if not. | |
2211 | * | |
2212 | * Notes: | |
2213 | * This routine transitions the device to the SDEV_RUNNING state | |
2214 | * (which must be a legal transition) allowing the midlayer to | |
2215 | * goose the queue for this device. This routine assumes the | |
2216 | * host_lock is held upon entry. | |
2217 | **/ | |
2218 | int | |
2219 | scsi_internal_device_unblock(struct scsi_device *sdev) | |
2220 | { | |
2221 | request_queue_t *q = sdev->request_queue; | |
2222 | int err; | |
2223 | unsigned long flags; | |
2224 | ||
2225 | /* | |
2226 | * Try to transition the scsi device to SDEV_RUNNING | |
2227 | * and goose the device queue if successful. | |
2228 | */ | |
2229 | err = scsi_device_set_state(sdev, SDEV_RUNNING); | |
2230 | if (err) | |
2231 | return err; | |
2232 | ||
2233 | spin_lock_irqsave(q->queue_lock, flags); | |
2234 | blk_start_queue(q); | |
2235 | spin_unlock_irqrestore(q->queue_lock, flags); | |
2236 | ||
2237 | return 0; | |
2238 | } | |
2239 | EXPORT_SYMBOL_GPL(scsi_internal_device_unblock); | |
2240 | ||
2241 | static void | |
2242 | device_block(struct scsi_device *sdev, void *data) | |
2243 | { | |
2244 | scsi_internal_device_block(sdev); | |
2245 | } | |
2246 | ||
2247 | static int | |
2248 | target_block(struct device *dev, void *data) | |
2249 | { | |
2250 | if (scsi_is_target_device(dev)) | |
2251 | starget_for_each_device(to_scsi_target(dev), NULL, | |
2252 | device_block); | |
2253 | return 0; | |
2254 | } | |
2255 | ||
2256 | void | |
2257 | scsi_target_block(struct device *dev) | |
2258 | { | |
2259 | if (scsi_is_target_device(dev)) | |
2260 | starget_for_each_device(to_scsi_target(dev), NULL, | |
2261 | device_block); | |
2262 | else | |
2263 | device_for_each_child(dev, NULL, target_block); | |
2264 | } | |
2265 | EXPORT_SYMBOL_GPL(scsi_target_block); | |
2266 | ||
2267 | static void | |
2268 | device_unblock(struct scsi_device *sdev, void *data) | |
2269 | { | |
2270 | scsi_internal_device_unblock(sdev); | |
2271 | } | |
2272 | ||
2273 | static int | |
2274 | target_unblock(struct device *dev, void *data) | |
2275 | { | |
2276 | if (scsi_is_target_device(dev)) | |
2277 | starget_for_each_device(to_scsi_target(dev), NULL, | |
2278 | device_unblock); | |
2279 | return 0; | |
2280 | } | |
2281 | ||
2282 | void | |
2283 | scsi_target_unblock(struct device *dev) | |
2284 | { | |
2285 | if (scsi_is_target_device(dev)) | |
2286 | starget_for_each_device(to_scsi_target(dev), NULL, | |
2287 | device_unblock); | |
2288 | else | |
2289 | device_for_each_child(dev, NULL, target_unblock); | |
2290 | } | |
2291 | EXPORT_SYMBOL_GPL(scsi_target_unblock); | |
cdb8c2a6 GL |
2292 | |
2293 | /** | |
2294 | * scsi_kmap_atomic_sg - find and atomically map an sg-elemnt | |
2295 | * @sg: scatter-gather list | |
2296 | * @sg_count: number of segments in sg | |
2297 | * @offset: offset in bytes into sg, on return offset into the mapped area | |
2298 | * @len: bytes to map, on return number of bytes mapped | |
2299 | * | |
2300 | * Returns virtual address of the start of the mapped page | |
2301 | */ | |
2302 | void *scsi_kmap_atomic_sg(struct scatterlist *sg, int sg_count, | |
2303 | size_t *offset, size_t *len) | |
2304 | { | |
2305 | int i; | |
2306 | size_t sg_len = 0, len_complete = 0; | |
2307 | struct page *page; | |
2308 | ||
2309 | for (i = 0; i < sg_count; i++) { | |
2310 | len_complete = sg_len; /* Complete sg-entries */ | |
2311 | sg_len += sg[i].length; | |
2312 | if (sg_len > *offset) | |
2313 | break; | |
2314 | } | |
2315 | ||
2316 | if (unlikely(i == sg_count)) { | |
169e1a2a AM |
2317 | printk(KERN_ERR "%s: Bytes in sg: %zu, requested offset %zu, " |
2318 | "elements %d\n", | |
cdb8c2a6 GL |
2319 | __FUNCTION__, sg_len, *offset, sg_count); |
2320 | WARN_ON(1); | |
2321 | return NULL; | |
2322 | } | |
2323 | ||
2324 | /* Offset starting from the beginning of first page in this sg-entry */ | |
2325 | *offset = *offset - len_complete + sg[i].offset; | |
2326 | ||
2327 | /* Assumption: contiguous pages can be accessed as "page + i" */ | |
2328 | page = nth_page(sg[i].page, (*offset >> PAGE_SHIFT)); | |
2329 | *offset &= ~PAGE_MASK; | |
2330 | ||
2331 | /* Bytes in this sg-entry from *offset to the end of the page */ | |
2332 | sg_len = PAGE_SIZE - *offset; | |
2333 | if (*len > sg_len) | |
2334 | *len = sg_len; | |
2335 | ||
2336 | return kmap_atomic(page, KM_BIO_SRC_IRQ); | |
2337 | } | |
2338 | EXPORT_SYMBOL(scsi_kmap_atomic_sg); | |
2339 | ||
2340 | /** | |
2341 | * scsi_kunmap_atomic_sg - atomically unmap a virtual address, previously | |
2342 | * mapped with scsi_kmap_atomic_sg | |
2343 | * @virt: virtual address to be unmapped | |
2344 | */ | |
2345 | void scsi_kunmap_atomic_sg(void *virt) | |
2346 | { | |
2347 | kunmap_atomic(virt, KM_BIO_SRC_IRQ); | |
2348 | } | |
2349 | EXPORT_SYMBOL(scsi_kunmap_atomic_sg); |