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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> | |
d3f46f39 | 11 | #include <linux/bitops.h> |
1da177e4 LT |
12 | #include <linux/blkdev.h> |
13 | #include <linux/completion.h> | |
14 | #include <linux/kernel.h> | |
15 | #include <linux/mempool.h> | |
16 | #include <linux/slab.h> | |
17 | #include <linux/init.h> | |
18 | #include <linux/pci.h> | |
19 | #include <linux/delay.h> | |
faead26d | 20 | #include <linux/hardirq.h> |
c6132da1 | 21 | #include <linux/scatterlist.h> |
1da177e4 LT |
22 | |
23 | #include <scsi/scsi.h> | |
beb40487 | 24 | #include <scsi/scsi_cmnd.h> |
1da177e4 LT |
25 | #include <scsi/scsi_dbg.h> |
26 | #include <scsi/scsi_device.h> | |
27 | #include <scsi/scsi_driver.h> | |
28 | #include <scsi/scsi_eh.h> | |
29 | #include <scsi/scsi_host.h> | |
1da177e4 LT |
30 | |
31 | #include "scsi_priv.h" | |
32 | #include "scsi_logging.h" | |
33 | ||
34 | ||
6391a113 | 35 | #define SG_MEMPOOL_NR ARRAY_SIZE(scsi_sg_pools) |
5972511b | 36 | #define SG_MEMPOOL_SIZE 2 |
1da177e4 LT |
37 | |
38 | struct scsi_host_sg_pool { | |
39 | size_t size; | |
a8474ce2 | 40 | char *name; |
e18b890b | 41 | struct kmem_cache *slab; |
1da177e4 LT |
42 | mempool_t *pool; |
43 | }; | |
44 | ||
d3f46f39 JB |
45 | #define SP(x) { x, "sgpool-" __stringify(x) } |
46 | #if (SCSI_MAX_SG_SEGMENTS < 32) | |
47 | #error SCSI_MAX_SG_SEGMENTS is too small (must be 32 or greater) | |
48 | #endif | |
52c1da39 | 49 | static struct scsi_host_sg_pool scsi_sg_pools[] = { |
1da177e4 LT |
50 | SP(8), |
51 | SP(16), | |
fd820f40 | 52 | #if (SCSI_MAX_SG_SEGMENTS > 32) |
d3f46f39 | 53 | SP(32), |
fd820f40 | 54 | #if (SCSI_MAX_SG_SEGMENTS > 64) |
d3f46f39 JB |
55 | SP(64), |
56 | #if (SCSI_MAX_SG_SEGMENTS > 128) | |
1da177e4 | 57 | SP(128), |
d3f46f39 JB |
58 | #if (SCSI_MAX_SG_SEGMENTS > 256) |
59 | #error SCSI_MAX_SG_SEGMENTS is too large (256 MAX) | |
fd820f40 FT |
60 | #endif |
61 | #endif | |
62 | #endif | |
d3f46f39 JB |
63 | #endif |
64 | SP(SCSI_MAX_SG_SEGMENTS) | |
a8474ce2 | 65 | }; |
1da177e4 LT |
66 | #undef SP |
67 | ||
6f9a35e2 BH |
68 | static struct kmem_cache *scsi_bidi_sdb_cache; |
69 | ||
a1bf9d1d | 70 | static void scsi_run_queue(struct request_queue *q); |
e91442b6 JB |
71 | |
72 | /* | |
73 | * Function: scsi_unprep_request() | |
74 | * | |
75 | * Purpose: Remove all preparation done for a request, including its | |
76 | * associated scsi_cmnd, so that it can be requeued. | |
77 | * | |
78 | * Arguments: req - request to unprepare | |
79 | * | |
80 | * Lock status: Assumed that no locks are held upon entry. | |
81 | * | |
82 | * Returns: Nothing. | |
83 | */ | |
84 | static void scsi_unprep_request(struct request *req) | |
85 | { | |
86 | struct scsi_cmnd *cmd = req->special; | |
87 | ||
4aff5e23 | 88 | req->cmd_flags &= ~REQ_DONTPREP; |
beb40487 | 89 | req->special = NULL; |
e91442b6 | 90 | |
e91442b6 JB |
91 | scsi_put_command(cmd); |
92 | } | |
a1bf9d1d | 93 | |
1da177e4 LT |
94 | /* |
95 | * Function: scsi_queue_insert() | |
96 | * | |
97 | * Purpose: Insert a command in the midlevel queue. | |
98 | * | |
99 | * Arguments: cmd - command that we are adding to queue. | |
100 | * reason - why we are inserting command to queue. | |
101 | * | |
102 | * Lock status: Assumed that lock is not held upon entry. | |
103 | * | |
104 | * Returns: Nothing. | |
105 | * | |
106 | * Notes: We do this for one of two cases. Either the host is busy | |
107 | * and it cannot accept any more commands for the time being, | |
108 | * or the device returned QUEUE_FULL and can accept no more | |
109 | * commands. | |
110 | * Notes: This could be called either from an interrupt context or a | |
111 | * normal process context. | |
112 | */ | |
113 | int scsi_queue_insert(struct scsi_cmnd *cmd, int reason) | |
114 | { | |
115 | struct Scsi_Host *host = cmd->device->host; | |
116 | struct scsi_device *device = cmd->device; | |
a1bf9d1d TH |
117 | struct request_queue *q = device->request_queue; |
118 | unsigned long flags; | |
1da177e4 LT |
119 | |
120 | SCSI_LOG_MLQUEUE(1, | |
121 | printk("Inserting command %p into mlqueue\n", cmd)); | |
122 | ||
123 | /* | |
d8c37e7b | 124 | * Set the appropriate busy bit for the device/host. |
1da177e4 LT |
125 | * |
126 | * If the host/device isn't busy, assume that something actually | |
127 | * completed, and that we should be able to queue a command now. | |
128 | * | |
129 | * Note that the prior mid-layer assumption that any host could | |
130 | * always queue at least one command is now broken. The mid-layer | |
131 | * will implement a user specifiable stall (see | |
132 | * scsi_host.max_host_blocked and scsi_device.max_device_blocked) | |
133 | * if a command is requeued with no other commands outstanding | |
134 | * either for the device or for the host. | |
135 | */ | |
136 | if (reason == SCSI_MLQUEUE_HOST_BUSY) | |
137 | host->host_blocked = host->max_host_blocked; | |
138 | else if (reason == SCSI_MLQUEUE_DEVICE_BUSY) | |
139 | device->device_blocked = device->max_device_blocked; | |
140 | ||
1da177e4 LT |
141 | /* |
142 | * Decrement the counters, since these commands are no longer | |
143 | * active on the host/device. | |
144 | */ | |
145 | scsi_device_unbusy(device); | |
146 | ||
147 | /* | |
a1bf9d1d TH |
148 | * Requeue this command. It will go before all other commands |
149 | * that are already in the queue. | |
1da177e4 LT |
150 | * |
151 | * NOTE: there is magic here about the way the queue is plugged if | |
152 | * we have no outstanding commands. | |
153 | * | |
a1bf9d1d | 154 | * Although we *don't* plug the queue, we call the request |
1da177e4 LT |
155 | * function. The SCSI request function detects the blocked condition |
156 | * and plugs the queue appropriately. | |
a1bf9d1d TH |
157 | */ |
158 | spin_lock_irqsave(q->queue_lock, flags); | |
59897dad | 159 | blk_requeue_request(q, cmd->request); |
a1bf9d1d TH |
160 | spin_unlock_irqrestore(q->queue_lock, flags); |
161 | ||
162 | scsi_run_queue(q); | |
163 | ||
1da177e4 LT |
164 | return 0; |
165 | } | |
166 | ||
39216033 | 167 | /** |
33aa687d | 168 | * scsi_execute - insert request and wait for the result |
39216033 JB |
169 | * @sdev: scsi device |
170 | * @cmd: scsi command | |
171 | * @data_direction: data direction | |
172 | * @buffer: data buffer | |
173 | * @bufflen: len of buffer | |
174 | * @sense: optional sense buffer | |
175 | * @timeout: request timeout in seconds | |
176 | * @retries: number of times to retry request | |
33aa687d | 177 | * @flags: or into request flags; |
39216033 | 178 | * |
59c51591 | 179 | * returns the req->errors value which is the scsi_cmnd result |
ea73a9f2 | 180 | * field. |
eb44820c | 181 | */ |
33aa687d JB |
182 | int scsi_execute(struct scsi_device *sdev, const unsigned char *cmd, |
183 | int data_direction, void *buffer, unsigned bufflen, | |
184 | unsigned char *sense, int timeout, int retries, int flags) | |
39216033 JB |
185 | { |
186 | struct request *req; | |
187 | int write = (data_direction == DMA_TO_DEVICE); | |
188 | int ret = DRIVER_ERROR << 24; | |
189 | ||
190 | req = blk_get_request(sdev->request_queue, write, __GFP_WAIT); | |
191 | ||
192 | if (bufflen && blk_rq_map_kern(sdev->request_queue, req, | |
193 | buffer, bufflen, __GFP_WAIT)) | |
194 | goto out; | |
195 | ||
196 | req->cmd_len = COMMAND_SIZE(cmd[0]); | |
197 | memcpy(req->cmd, cmd, req->cmd_len); | |
198 | req->sense = sense; | |
199 | req->sense_len = 0; | |
17e01f21 | 200 | req->retries = retries; |
39216033 | 201 | req->timeout = timeout; |
4aff5e23 JA |
202 | req->cmd_type = REQ_TYPE_BLOCK_PC; |
203 | req->cmd_flags |= flags | REQ_QUIET | REQ_PREEMPT; | |
39216033 JB |
204 | |
205 | /* | |
206 | * head injection *required* here otherwise quiesce won't work | |
207 | */ | |
208 | blk_execute_rq(req->q, NULL, req, 1); | |
209 | ||
210 | ret = req->errors; | |
211 | out: | |
212 | blk_put_request(req); | |
213 | ||
214 | return ret; | |
215 | } | |
33aa687d | 216 | EXPORT_SYMBOL(scsi_execute); |
39216033 | 217 | |
ea73a9f2 JB |
218 | |
219 | int scsi_execute_req(struct scsi_device *sdev, const unsigned char *cmd, | |
220 | int data_direction, void *buffer, unsigned bufflen, | |
221 | struct scsi_sense_hdr *sshdr, int timeout, int retries) | |
222 | { | |
223 | char *sense = NULL; | |
1ccb48bb | 224 | int result; |
225 | ||
ea73a9f2 | 226 | if (sshdr) { |
24669f75 | 227 | sense = kzalloc(SCSI_SENSE_BUFFERSIZE, GFP_NOIO); |
ea73a9f2 JB |
228 | if (!sense) |
229 | return DRIVER_ERROR << 24; | |
ea73a9f2 | 230 | } |
1ccb48bb | 231 | result = scsi_execute(sdev, cmd, data_direction, buffer, bufflen, |
24669f75 | 232 | sense, timeout, retries, 0); |
ea73a9f2 | 233 | if (sshdr) |
e514385b | 234 | scsi_normalize_sense(sense, SCSI_SENSE_BUFFERSIZE, sshdr); |
ea73a9f2 JB |
235 | |
236 | kfree(sense); | |
237 | return result; | |
238 | } | |
239 | EXPORT_SYMBOL(scsi_execute_req); | |
240 | ||
6e68af66 MC |
241 | struct scsi_io_context { |
242 | void *data; | |
243 | void (*done)(void *data, char *sense, int result, int resid); | |
244 | char sense[SCSI_SENSE_BUFFERSIZE]; | |
245 | }; | |
246 | ||
e18b890b | 247 | static struct kmem_cache *scsi_io_context_cache; |
aa7b5cd7 | 248 | |
e650c305 | 249 | static void scsi_end_async(struct request *req, int uptodate) |
6e68af66 MC |
250 | { |
251 | struct scsi_io_context *sioc = req->end_io_data; | |
252 | ||
253 | if (sioc->done) | |
254 | sioc->done(sioc->data, sioc->sense, req->errors, req->data_len); | |
255 | ||
aa7b5cd7 | 256 | kmem_cache_free(scsi_io_context_cache, sioc); |
6e68af66 MC |
257 | __blk_put_request(req->q, req); |
258 | } | |
259 | ||
260 | static int scsi_merge_bio(struct request *rq, struct bio *bio) | |
261 | { | |
262 | struct request_queue *q = rq->q; | |
263 | ||
264 | bio->bi_flags &= ~(1 << BIO_SEG_VALID); | |
265 | if (rq_data_dir(rq) == WRITE) | |
266 | bio->bi_rw |= (1 << BIO_RW); | |
267 | blk_queue_bounce(q, &bio); | |
268 | ||
3001ca77 | 269 | return blk_rq_append_bio(q, rq, bio); |
6e68af66 MC |
270 | } |
271 | ||
6712ecf8 | 272 | static void scsi_bi_endio(struct bio *bio, int error) |
6e68af66 | 273 | { |
6e68af66 | 274 | bio_put(bio); |
6e68af66 MC |
275 | } |
276 | ||
277 | /** | |
278 | * scsi_req_map_sg - map a scatterlist into a request | |
279 | * @rq: request to fill | |
eb44820c | 280 | * @sgl: scatterlist |
6e68af66 MC |
281 | * @nsegs: number of elements |
282 | * @bufflen: len of buffer | |
283 | * @gfp: memory allocation flags | |
284 | * | |
285 | * scsi_req_map_sg maps a scatterlist into a request so that the | |
286 | * request can be sent to the block layer. We do not trust the scatterlist | |
287 | * sent to use, as some ULDs use that struct to only organize the pages. | |
288 | */ | |
289 | static int scsi_req_map_sg(struct request *rq, struct scatterlist *sgl, | |
290 | int nsegs, unsigned bufflen, gfp_t gfp) | |
291 | { | |
292 | struct request_queue *q = rq->q; | |
f5235962 | 293 | int nr_pages = (bufflen + sgl[0].offset + PAGE_SIZE - 1) >> PAGE_SHIFT; |
bd441dea | 294 | unsigned int data_len = bufflen, len, bytes, off; |
c6132da1 | 295 | struct scatterlist *sg; |
6e68af66 MC |
296 | struct page *page; |
297 | struct bio *bio = NULL; | |
298 | int i, err, nr_vecs = 0; | |
299 | ||
c6132da1 | 300 | for_each_sg(sgl, sg, nsegs, i) { |
45711f1a | 301 | page = sg_page(sg); |
c6132da1 JA |
302 | off = sg->offset; |
303 | len = sg->length; | |
304 | data_len += len; | |
6e68af66 | 305 | |
bd441dea MC |
306 | while (len > 0 && data_len > 0) { |
307 | /* | |
308 | * sg sends a scatterlist that is larger than | |
309 | * the data_len it wants transferred for certain | |
310 | * IO sizes | |
311 | */ | |
6e68af66 | 312 | bytes = min_t(unsigned int, len, PAGE_SIZE - off); |
bd441dea | 313 | bytes = min(bytes, data_len); |
6e68af66 MC |
314 | |
315 | if (!bio) { | |
316 | nr_vecs = min_t(int, BIO_MAX_PAGES, nr_pages); | |
317 | nr_pages -= nr_vecs; | |
318 | ||
319 | bio = bio_alloc(gfp, nr_vecs); | |
320 | if (!bio) { | |
321 | err = -ENOMEM; | |
322 | goto free_bios; | |
323 | } | |
324 | bio->bi_end_io = scsi_bi_endio; | |
325 | } | |
326 | ||
327 | if (bio_add_pc_page(q, bio, page, bytes, off) != | |
328 | bytes) { | |
329 | bio_put(bio); | |
330 | err = -EINVAL; | |
331 | goto free_bios; | |
332 | } | |
333 | ||
334 | if (bio->bi_vcnt >= nr_vecs) { | |
335 | err = scsi_merge_bio(rq, bio); | |
336 | if (err) { | |
6712ecf8 | 337 | bio_endio(bio, 0); |
6e68af66 MC |
338 | goto free_bios; |
339 | } | |
340 | bio = NULL; | |
341 | } | |
342 | ||
343 | page++; | |
344 | len -= bytes; | |
bd441dea | 345 | data_len -=bytes; |
6e68af66 MC |
346 | off = 0; |
347 | } | |
348 | } | |
349 | ||
350 | rq->buffer = rq->data = NULL; | |
bd441dea | 351 | rq->data_len = bufflen; |
6e68af66 MC |
352 | return 0; |
353 | ||
354 | free_bios: | |
355 | while ((bio = rq->bio) != NULL) { | |
356 | rq->bio = bio->bi_next; | |
357 | /* | |
358 | * call endio instead of bio_put incase it was bounced | |
359 | */ | |
6712ecf8 | 360 | bio_endio(bio, 0); |
6e68af66 MC |
361 | } |
362 | ||
363 | return err; | |
364 | } | |
365 | ||
366 | /** | |
367 | * scsi_execute_async - insert request | |
368 | * @sdev: scsi device | |
369 | * @cmd: scsi command | |
bb1d1073 | 370 | * @cmd_len: length of scsi cdb |
eb44820c | 371 | * @data_direction: DMA_TO_DEVICE, DMA_FROM_DEVICE, or DMA_NONE |
6e68af66 MC |
372 | * @buffer: data buffer (this can be a kernel buffer or scatterlist) |
373 | * @bufflen: len of buffer | |
374 | * @use_sg: if buffer is a scatterlist this is the number of elements | |
375 | * @timeout: request timeout in seconds | |
376 | * @retries: number of times to retry request | |
eb44820c RL |
377 | * @privdata: data passed to done() |
378 | * @done: callback function when done | |
379 | * @gfp: memory allocation flags | |
380 | */ | |
6e68af66 | 381 | int scsi_execute_async(struct scsi_device *sdev, const unsigned char *cmd, |
bb1d1073 | 382 | int cmd_len, int data_direction, void *buffer, unsigned bufflen, |
6e68af66 MC |
383 | int use_sg, int timeout, int retries, void *privdata, |
384 | void (*done)(void *, char *, int, int), gfp_t gfp) | |
385 | { | |
386 | struct request *req; | |
387 | struct scsi_io_context *sioc; | |
388 | int err = 0; | |
389 | int write = (data_direction == DMA_TO_DEVICE); | |
390 | ||
c3762229 | 391 | sioc = kmem_cache_zalloc(scsi_io_context_cache, gfp); |
6e68af66 MC |
392 | if (!sioc) |
393 | return DRIVER_ERROR << 24; | |
394 | ||
395 | req = blk_get_request(sdev->request_queue, write, gfp); | |
396 | if (!req) | |
397 | goto free_sense; | |
4aff5e23 JA |
398 | req->cmd_type = REQ_TYPE_BLOCK_PC; |
399 | req->cmd_flags |= REQ_QUIET; | |
6e68af66 MC |
400 | |
401 | if (use_sg) | |
402 | err = scsi_req_map_sg(req, buffer, use_sg, bufflen, gfp); | |
403 | else if (bufflen) | |
404 | err = blk_rq_map_kern(req->q, req, buffer, bufflen, gfp); | |
405 | ||
406 | if (err) | |
407 | goto free_req; | |
408 | ||
bb1d1073 | 409 | req->cmd_len = cmd_len; |
097b8457 | 410 | memset(req->cmd, 0, BLK_MAX_CDB); /* ATAPI hates garbage after CDB */ |
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: | |
6470f2ba | 427 | kmem_cache_free(scsi_io_context_cache, sioc); |
6e68af66 MC |
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 | * | |
1da177e4 LT |
439 | * Notes: This function has the job of initializing a number of |
440 | * fields related to error handling. Typically this will | |
441 | * be called once for each command, as required. | |
442 | */ | |
631c228c | 443 | static void scsi_init_cmd_errh(struct scsi_cmnd *cmd) |
1da177e4 | 444 | { |
1da177e4 | 445 | cmd->serial_number = 0; |
30b0c37b | 446 | scsi_set_resid(cmd, 0); |
b80ca4f7 | 447 | memset(cmd->sense_buffer, 0, SCSI_SENSE_BUFFERSIZE); |
1da177e4 LT |
448 | if (cmd->cmd_len == 0) |
449 | cmd->cmd_len = COMMAND_SIZE(cmd->cmnd[0]); | |
1da177e4 LT |
450 | } |
451 | ||
452 | void scsi_device_unbusy(struct scsi_device *sdev) | |
453 | { | |
454 | struct Scsi_Host *shost = sdev->host; | |
455 | unsigned long flags; | |
456 | ||
457 | spin_lock_irqsave(shost->host_lock, flags); | |
458 | shost->host_busy--; | |
939647ee | 459 | if (unlikely(scsi_host_in_recovery(shost) && |
ee7863bc | 460 | (shost->host_failed || shost->host_eh_scheduled))) |
1da177e4 LT |
461 | scsi_eh_wakeup(shost); |
462 | spin_unlock(shost->host_lock); | |
152587de | 463 | spin_lock(sdev->request_queue->queue_lock); |
1da177e4 | 464 | sdev->device_busy--; |
152587de | 465 | spin_unlock_irqrestore(sdev->request_queue->queue_lock, flags); |
1da177e4 LT |
466 | } |
467 | ||
468 | /* | |
469 | * Called for single_lun devices on IO completion. Clear starget_sdev_user, | |
470 | * and call blk_run_queue for all the scsi_devices on the target - | |
471 | * including current_sdev first. | |
472 | * | |
473 | * Called with *no* scsi locks held. | |
474 | */ | |
475 | static void scsi_single_lun_run(struct scsi_device *current_sdev) | |
476 | { | |
477 | struct Scsi_Host *shost = current_sdev->host; | |
478 | struct scsi_device *sdev, *tmp; | |
479 | struct scsi_target *starget = scsi_target(current_sdev); | |
480 | unsigned long flags; | |
481 | ||
482 | spin_lock_irqsave(shost->host_lock, flags); | |
483 | starget->starget_sdev_user = NULL; | |
484 | spin_unlock_irqrestore(shost->host_lock, flags); | |
485 | ||
486 | /* | |
487 | * Call blk_run_queue for all LUNs on the target, starting with | |
488 | * current_sdev. We race with others (to set starget_sdev_user), | |
489 | * but in most cases, we will be first. Ideally, each LU on the | |
490 | * target would get some limited time or requests on the target. | |
491 | */ | |
492 | blk_run_queue(current_sdev->request_queue); | |
493 | ||
494 | spin_lock_irqsave(shost->host_lock, flags); | |
495 | if (starget->starget_sdev_user) | |
496 | goto out; | |
497 | list_for_each_entry_safe(sdev, tmp, &starget->devices, | |
498 | same_target_siblings) { | |
499 | if (sdev == current_sdev) | |
500 | continue; | |
501 | if (scsi_device_get(sdev)) | |
502 | continue; | |
503 | ||
504 | spin_unlock_irqrestore(shost->host_lock, flags); | |
505 | blk_run_queue(sdev->request_queue); | |
506 | spin_lock_irqsave(shost->host_lock, flags); | |
507 | ||
508 | scsi_device_put(sdev); | |
509 | } | |
510 | out: | |
511 | spin_unlock_irqrestore(shost->host_lock, flags); | |
512 | } | |
513 | ||
514 | /* | |
515 | * Function: scsi_run_queue() | |
516 | * | |
517 | * Purpose: Select a proper request queue to serve next | |
518 | * | |
519 | * Arguments: q - last request's queue | |
520 | * | |
521 | * Returns: Nothing | |
522 | * | |
523 | * Notes: The previous command was completely finished, start | |
524 | * a new one if possible. | |
525 | */ | |
526 | static void scsi_run_queue(struct request_queue *q) | |
527 | { | |
528 | struct scsi_device *sdev = q->queuedata; | |
529 | struct Scsi_Host *shost = sdev->host; | |
530 | unsigned long flags; | |
531 | ||
25d7c363 | 532 | if (scsi_target(sdev)->single_lun) |
1da177e4 LT |
533 | scsi_single_lun_run(sdev); |
534 | ||
535 | spin_lock_irqsave(shost->host_lock, flags); | |
536 | while (!list_empty(&shost->starved_list) && | |
537 | !shost->host_blocked && !shost->host_self_blocked && | |
538 | !((shost->can_queue > 0) && | |
539 | (shost->host_busy >= shost->can_queue))) { | |
540 | /* | |
541 | * As long as shost is accepting commands and we have | |
542 | * starved queues, call blk_run_queue. scsi_request_fn | |
543 | * drops the queue_lock and can add us back to the | |
544 | * starved_list. | |
545 | * | |
546 | * host_lock protects the starved_list and starved_entry. | |
547 | * scsi_request_fn must get the host_lock before checking | |
548 | * or modifying starved_list or starved_entry. | |
549 | */ | |
550 | sdev = list_entry(shost->starved_list.next, | |
551 | struct scsi_device, starved_entry); | |
552 | list_del_init(&sdev->starved_entry); | |
553 | spin_unlock_irqrestore(shost->host_lock, flags); | |
554 | ||
04846f25 AH |
555 | |
556 | if (test_bit(QUEUE_FLAG_REENTER, &q->queue_flags) && | |
557 | !test_and_set_bit(QUEUE_FLAG_REENTER, | |
558 | &sdev->request_queue->queue_flags)) { | |
559 | blk_run_queue(sdev->request_queue); | |
560 | clear_bit(QUEUE_FLAG_REENTER, | |
561 | &sdev->request_queue->queue_flags); | |
562 | } else | |
563 | blk_run_queue(sdev->request_queue); | |
1da177e4 LT |
564 | |
565 | spin_lock_irqsave(shost->host_lock, flags); | |
566 | if (unlikely(!list_empty(&sdev->starved_entry))) | |
567 | /* | |
568 | * sdev lost a race, and was put back on the | |
569 | * starved list. This is unlikely but without this | |
570 | * in theory we could loop forever. | |
571 | */ | |
572 | break; | |
573 | } | |
574 | spin_unlock_irqrestore(shost->host_lock, flags); | |
575 | ||
576 | blk_run_queue(q); | |
577 | } | |
578 | ||
579 | /* | |
580 | * Function: scsi_requeue_command() | |
581 | * | |
582 | * Purpose: Handle post-processing of completed commands. | |
583 | * | |
584 | * Arguments: q - queue to operate on | |
585 | * cmd - command that may need to be requeued. | |
586 | * | |
587 | * Returns: Nothing | |
588 | * | |
589 | * Notes: After command completion, there may be blocks left | |
590 | * over which weren't finished by the previous command | |
591 | * this can be for a number of reasons - the main one is | |
592 | * I/O errors in the middle of the request, in which case | |
593 | * we need to request the blocks that come after the bad | |
594 | * sector. | |
e91442b6 | 595 | * Notes: Upon return, cmd is a stale pointer. |
1da177e4 LT |
596 | */ |
597 | static void scsi_requeue_command(struct request_queue *q, struct scsi_cmnd *cmd) | |
598 | { | |
e91442b6 | 599 | struct request *req = cmd->request; |
283369cc TH |
600 | unsigned long flags; |
601 | ||
e91442b6 | 602 | scsi_unprep_request(req); |
283369cc | 603 | spin_lock_irqsave(q->queue_lock, flags); |
e91442b6 | 604 | blk_requeue_request(q, req); |
283369cc | 605 | spin_unlock_irqrestore(q->queue_lock, flags); |
1da177e4 LT |
606 | |
607 | scsi_run_queue(q); | |
608 | } | |
609 | ||
610 | void scsi_next_command(struct scsi_cmnd *cmd) | |
611 | { | |
49d7bc64 LT |
612 | struct scsi_device *sdev = cmd->device; |
613 | struct request_queue *q = sdev->request_queue; | |
614 | ||
615 | /* need to hold a reference on the device before we let go of the cmd */ | |
616 | get_device(&sdev->sdev_gendev); | |
1da177e4 LT |
617 | |
618 | scsi_put_command(cmd); | |
619 | scsi_run_queue(q); | |
49d7bc64 LT |
620 | |
621 | /* ok to remove device now */ | |
622 | put_device(&sdev->sdev_gendev); | |
1da177e4 LT |
623 | } |
624 | ||
625 | void scsi_run_host_queues(struct Scsi_Host *shost) | |
626 | { | |
627 | struct scsi_device *sdev; | |
628 | ||
629 | shost_for_each_device(sdev, shost) | |
630 | scsi_run_queue(sdev->request_queue); | |
631 | } | |
632 | ||
633 | /* | |
634 | * Function: scsi_end_request() | |
635 | * | |
636 | * Purpose: Post-processing of completed commands (usually invoked at end | |
637 | * of upper level post-processing and scsi_io_completion). | |
638 | * | |
639 | * Arguments: cmd - command that is complete. | |
610d8b0c | 640 | * error - 0 if I/O indicates success, < 0 for I/O error. |
1da177e4 LT |
641 | * bytes - number of bytes of completed I/O |
642 | * requeue - indicates whether we should requeue leftovers. | |
643 | * | |
644 | * Lock status: Assumed that lock is not held upon entry. | |
645 | * | |
e91442b6 | 646 | * Returns: cmd if requeue required, NULL otherwise. |
1da177e4 LT |
647 | * |
648 | * Notes: This is called for block device requests in order to | |
649 | * mark some number of sectors as complete. | |
650 | * | |
651 | * We are guaranteeing that the request queue will be goosed | |
652 | * at some point during this call. | |
e91442b6 | 653 | * Notes: If cmd was requeued, upon return it will be a stale pointer. |
1da177e4 | 654 | */ |
610d8b0c | 655 | static struct scsi_cmnd *scsi_end_request(struct scsi_cmnd *cmd, int error, |
1da177e4 LT |
656 | int bytes, int requeue) |
657 | { | |
165125e1 | 658 | struct request_queue *q = cmd->device->request_queue; |
1da177e4 | 659 | struct request *req = cmd->request; |
1da177e4 LT |
660 | |
661 | /* | |
662 | * If there are blocks left over at the end, set up the command | |
663 | * to queue the remainder of them. | |
664 | */ | |
610d8b0c | 665 | if (blk_end_request(req, error, bytes)) { |
1da177e4 LT |
666 | int leftover = (req->hard_nr_sectors << 9); |
667 | ||
668 | if (blk_pc_request(req)) | |
669 | leftover = req->data_len; | |
670 | ||
671 | /* kill remainder if no retrys */ | |
610d8b0c KU |
672 | if (error && blk_noretry_request(req)) |
673 | blk_end_request(req, error, leftover); | |
1da177e4 | 674 | else { |
e91442b6 | 675 | if (requeue) { |
1da177e4 LT |
676 | /* |
677 | * Bleah. Leftovers again. Stick the | |
678 | * leftovers in the front of the | |
679 | * queue, and goose the queue again. | |
680 | */ | |
681 | scsi_requeue_command(q, cmd); | |
e91442b6 JB |
682 | cmd = NULL; |
683 | } | |
1da177e4 LT |
684 | return cmd; |
685 | } | |
686 | } | |
687 | ||
1da177e4 LT |
688 | /* |
689 | * This will goose the queue request function at the end, so we don't | |
690 | * need to worry about launching another command. | |
691 | */ | |
692 | scsi_next_command(cmd); | |
693 | return NULL; | |
694 | } | |
695 | ||
a8474ce2 JA |
696 | static inline unsigned int scsi_sgtable_index(unsigned short nents) |
697 | { | |
698 | unsigned int index; | |
699 | ||
d3f46f39 JB |
700 | BUG_ON(nents > SCSI_MAX_SG_SEGMENTS); |
701 | ||
702 | if (nents <= 8) | |
a8474ce2 | 703 | index = 0; |
d3f46f39 JB |
704 | else |
705 | index = get_count_order(nents) - 3; | |
1da177e4 | 706 | |
a8474ce2 JA |
707 | return index; |
708 | } | |
709 | ||
5ed7959e | 710 | static void scsi_sg_free(struct scatterlist *sgl, unsigned int nents) |
a8474ce2 JA |
711 | { |
712 | struct scsi_host_sg_pool *sgp; | |
a8474ce2 | 713 | |
5ed7959e JA |
714 | sgp = scsi_sg_pools + scsi_sgtable_index(nents); |
715 | mempool_free(sgl, sgp->pool); | |
716 | } | |
a8474ce2 | 717 | |
5ed7959e JA |
718 | static struct scatterlist *scsi_sg_alloc(unsigned int nents, gfp_t gfp_mask) |
719 | { | |
720 | struct scsi_host_sg_pool *sgp; | |
a8474ce2 | 721 | |
5ed7959e JA |
722 | sgp = scsi_sg_pools + scsi_sgtable_index(nents); |
723 | return mempool_alloc(sgp->pool, gfp_mask); | |
724 | } | |
a3bec5c5 | 725 | |
30b0c37b BH |
726 | static int scsi_alloc_sgtable(struct scsi_data_buffer *sdb, int nents, |
727 | gfp_t gfp_mask) | |
5ed7959e JA |
728 | { |
729 | int ret; | |
a8474ce2 | 730 | |
30b0c37b | 731 | BUG_ON(!nents); |
a8474ce2 | 732 | |
30b0c37b BH |
733 | ret = __sg_alloc_table(&sdb->table, nents, SCSI_MAX_SG_SEGMENTS, |
734 | gfp_mask, scsi_sg_alloc); | |
5ed7959e | 735 | if (unlikely(ret)) |
30b0c37b | 736 | __sg_free_table(&sdb->table, SCSI_MAX_SG_SEGMENTS, |
7cedb1f1 | 737 | scsi_sg_free); |
45711f1a | 738 | |
a8474ce2 | 739 | return ret; |
1da177e4 LT |
740 | } |
741 | ||
30b0c37b | 742 | static void scsi_free_sgtable(struct scsi_data_buffer *sdb) |
1da177e4 | 743 | { |
30b0c37b | 744 | __sg_free_table(&sdb->table, SCSI_MAX_SG_SEGMENTS, scsi_sg_free); |
1da177e4 LT |
745 | } |
746 | ||
747 | /* | |
748 | * Function: scsi_release_buffers() | |
749 | * | |
750 | * Purpose: Completion processing for block device I/O requests. | |
751 | * | |
752 | * Arguments: cmd - command that we are bailing. | |
753 | * | |
754 | * Lock status: Assumed that no lock is held upon entry. | |
755 | * | |
756 | * Returns: Nothing | |
757 | * | |
758 | * Notes: In the event that an upper level driver rejects a | |
759 | * command, we must release resources allocated during | |
760 | * the __init_io() function. Primarily this would involve | |
761 | * the scatter-gather table, and potentially any bounce | |
762 | * buffers. | |
763 | */ | |
bb52d82f | 764 | void scsi_release_buffers(struct scsi_cmnd *cmd) |
1da177e4 | 765 | { |
30b0c37b BH |
766 | if (cmd->sdb.table.nents) |
767 | scsi_free_sgtable(&cmd->sdb); | |
1da177e4 | 768 | |
30b0c37b | 769 | memset(&cmd->sdb, 0, sizeof(cmd->sdb)); |
6f9a35e2 BH |
770 | |
771 | if (scsi_bidi_cmnd(cmd)) { | |
772 | struct scsi_data_buffer *bidi_sdb = | |
773 | cmd->request->next_rq->special; | |
774 | scsi_free_sgtable(bidi_sdb); | |
775 | kmem_cache_free(scsi_bidi_sdb_cache, bidi_sdb); | |
776 | cmd->request->next_rq->special = NULL; | |
777 | } | |
1da177e4 | 778 | } |
bb52d82f | 779 | EXPORT_SYMBOL(scsi_release_buffers); |
1da177e4 | 780 | |
6f9a35e2 BH |
781 | /* |
782 | * Bidi commands Must be complete as a whole, both sides at once. | |
783 | * If part of the bytes were written and lld returned | |
784 | * scsi_in()->resid and/or scsi_out()->resid this information will be left | |
785 | * in req->data_len and req->next_rq->data_len. The upper-layer driver can | |
786 | * decide what to do with this information. | |
787 | */ | |
788 | void scsi_end_bidi_request(struct scsi_cmnd *cmd) | |
789 | { | |
b8de1631 KU |
790 | struct request *req = cmd->request; |
791 | unsigned int dlen = req->data_len; | |
792 | unsigned int next_dlen = req->next_rq->data_len; | |
793 | ||
794 | req->data_len = scsi_out(cmd)->resid; | |
795 | req->next_rq->data_len = scsi_in(cmd)->resid; | |
796 | ||
797 | /* The req and req->next_rq have not been completed */ | |
798 | BUG_ON(blk_end_bidi_request(req, 0, dlen, next_dlen)); | |
799 | ||
6f9a35e2 BH |
800 | scsi_release_buffers(cmd); |
801 | ||
802 | /* | |
803 | * This will goose the queue request function at the end, so we don't | |
804 | * need to worry about launching another command. | |
805 | */ | |
806 | scsi_next_command(cmd); | |
807 | } | |
808 | ||
1da177e4 LT |
809 | /* |
810 | * Function: scsi_io_completion() | |
811 | * | |
812 | * Purpose: Completion processing for block device I/O requests. | |
813 | * | |
814 | * Arguments: cmd - command that is finished. | |
815 | * | |
816 | * Lock status: Assumed that no lock is held upon entry. | |
817 | * | |
818 | * Returns: Nothing | |
819 | * | |
820 | * Notes: This function is matched in terms of capabilities to | |
821 | * the function that created the scatter-gather list. | |
822 | * In other words, if there are no bounce buffers | |
823 | * (the normal case for most drivers), we don't need | |
824 | * the logic to deal with cleaning up afterwards. | |
825 | * | |
826 | * We must do one of several things here: | |
827 | * | |
828 | * a) Call scsi_end_request. This will finish off the | |
829 | * specified number of sectors. If we are done, the | |
830 | * command block will be released, and the queue | |
831 | * function will be goosed. If we are not done, then | |
832 | * scsi_end_request will directly goose the queue. | |
833 | * | |
834 | * b) We can just use scsi_requeue_command() here. This would | |
835 | * be used if we just wanted to retry, for example. | |
836 | */ | |
03aba2f7 | 837 | void scsi_io_completion(struct scsi_cmnd *cmd, unsigned int good_bytes) |
1da177e4 LT |
838 | { |
839 | int result = cmd->result; | |
30b0c37b | 840 | int this_count = scsi_bufflen(cmd); |
165125e1 | 841 | struct request_queue *q = cmd->device->request_queue; |
1da177e4 LT |
842 | struct request *req = cmd->request; |
843 | int clear_errors = 1; | |
844 | struct scsi_sense_hdr sshdr; | |
845 | int sense_valid = 0; | |
846 | int sense_deferred = 0; | |
847 | ||
1da177e4 LT |
848 | if (result) { |
849 | sense_valid = scsi_command_normalize_sense(cmd, &sshdr); | |
850 | if (sense_valid) | |
851 | sense_deferred = scsi_sense_is_deferred(&sshdr); | |
852 | } | |
631c228c | 853 | |
1da177e4 LT |
854 | if (blk_pc_request(req)) { /* SG_IO ioctl from block level */ |
855 | req->errors = result; | |
856 | if (result) { | |
857 | clear_errors = 0; | |
858 | if (sense_valid && req->sense) { | |
859 | /* | |
860 | * SG_IO wants current and deferred errors | |
861 | */ | |
862 | int len = 8 + cmd->sense_buffer[7]; | |
863 | ||
864 | if (len > SCSI_SENSE_BUFFERSIZE) | |
865 | len = SCSI_SENSE_BUFFERSIZE; | |
866 | memcpy(req->sense, cmd->sense_buffer, len); | |
867 | req->sense_len = len; | |
868 | } | |
b22f687d | 869 | } |
6f9a35e2 BH |
870 | if (scsi_bidi_cmnd(cmd)) { |
871 | /* will also release_buffers */ | |
872 | scsi_end_bidi_request(cmd); | |
873 | return; | |
874 | } | |
30b0c37b | 875 | req->data_len = scsi_get_resid(cmd); |
1da177e4 LT |
876 | } |
877 | ||
6f9a35e2 | 878 | BUG_ON(blk_bidi_rq(req)); /* bidi not support for !blk_pc_request yet */ |
30b0c37b BH |
879 | scsi_release_buffers(cmd); |
880 | ||
1da177e4 LT |
881 | /* |
882 | * Next deal with any sectors which we were able to correctly | |
883 | * handle. | |
884 | */ | |
d6b0c537 JB |
885 | SCSI_LOG_HLCOMPLETE(1, printk("%ld sectors total, " |
886 | "%d bytes done.\n", | |
887 | req->nr_sectors, good_bytes)); | |
d6b0c537 JB |
888 | |
889 | if (clear_errors) | |
890 | req->errors = 0; | |
891 | ||
892 | /* A number of bytes were successfully read. If there | |
893 | * are leftovers and there is some kind of error | |
894 | * (result != 0), retry the rest. | |
895 | */ | |
610d8b0c | 896 | if (scsi_end_request(cmd, 0, good_bytes, result == 0) == NULL) |
d6b0c537 | 897 | return; |
03aba2f7 LT |
898 | |
899 | /* good_bytes = 0, or (inclusive) there were leftovers and | |
900 | * result = 0, so scsi_end_request couldn't retry. | |
1da177e4 LT |
901 | */ |
902 | if (sense_valid && !sense_deferred) { | |
903 | switch (sshdr.sense_key) { | |
904 | case UNIT_ATTENTION: | |
905 | if (cmd->device->removable) { | |
03aba2f7 | 906 | /* Detected disc change. Set a bit |
1da177e4 LT |
907 | * and quietly refuse further access. |
908 | */ | |
909 | cmd->device->changed = 1; | |
610d8b0c | 910 | scsi_end_request(cmd, -EIO, this_count, 1); |
1da177e4 LT |
911 | return; |
912 | } else { | |
03aba2f7 LT |
913 | /* Must have been a power glitch, or a |
914 | * bus reset. Could not have been a | |
915 | * media change, so we just retry the | |
916 | * request and see what happens. | |
917 | */ | |
1da177e4 LT |
918 | scsi_requeue_command(q, cmd); |
919 | return; | |
920 | } | |
921 | break; | |
922 | case ILLEGAL_REQUEST: | |
03aba2f7 LT |
923 | /* If we had an ILLEGAL REQUEST returned, then |
924 | * we may have performed an unsupported | |
925 | * command. The only thing this should be | |
926 | * would be a ten byte read where only a six | |
927 | * byte read was supported. Also, on a system | |
928 | * where READ CAPACITY failed, we may have | |
929 | * read past the end of the disk. | |
930 | */ | |
26a68019 JA |
931 | if ((cmd->device->use_10_for_rw && |
932 | sshdr.asc == 0x20 && sshdr.ascq == 0x00) && | |
1da177e4 LT |
933 | (cmd->cmnd[0] == READ_10 || |
934 | cmd->cmnd[0] == WRITE_10)) { | |
935 | cmd->device->use_10_for_rw = 0; | |
03aba2f7 LT |
936 | /* This will cause a retry with a |
937 | * 6-byte command. | |
1da177e4 LT |
938 | */ |
939 | scsi_requeue_command(q, cmd); | |
03aba2f7 | 940 | return; |
1da177e4 | 941 | } else { |
610d8b0c | 942 | scsi_end_request(cmd, -EIO, this_count, 1); |
1da177e4 LT |
943 | return; |
944 | } | |
945 | break; | |
946 | case NOT_READY: | |
03aba2f7 | 947 | /* If the device is in the process of becoming |
f3e93f73 | 948 | * ready, or has a temporary blockage, retry. |
1da177e4 | 949 | */ |
f3e93f73 JB |
950 | if (sshdr.asc == 0x04) { |
951 | switch (sshdr.ascq) { | |
952 | case 0x01: /* becoming ready */ | |
953 | case 0x04: /* format in progress */ | |
954 | case 0x05: /* rebuild in progress */ | |
955 | case 0x06: /* recalculation in progress */ | |
956 | case 0x07: /* operation in progress */ | |
957 | case 0x08: /* Long write in progress */ | |
958 | case 0x09: /* self test in progress */ | |
959 | scsi_requeue_command(q, cmd); | |
960 | return; | |
961 | default: | |
962 | break; | |
963 | } | |
1da177e4 | 964 | } |
311b581e JB |
965 | if (!(req->cmd_flags & REQ_QUIET)) |
966 | scsi_cmd_print_sense_hdr(cmd, | |
967 | "Device not ready", | |
968 | &sshdr); | |
969 | ||
610d8b0c | 970 | scsi_end_request(cmd, -EIO, this_count, 1); |
1da177e4 LT |
971 | return; |
972 | case VOLUME_OVERFLOW: | |
4aff5e23 | 973 | if (!(req->cmd_flags & REQ_QUIET)) { |
3bf743e7 | 974 | scmd_printk(KERN_INFO, cmd, |
03aba2f7 | 975 | "Volume overflow, CDB: "); |
631c228c | 976 | __scsi_print_command(cmd->cmnd); |
3173d8c3 JB |
977 | scsi_print_sense("", cmd); |
978 | } | |
03aba2f7 | 979 | /* See SSC3rXX or current. */ |
610d8b0c | 980 | scsi_end_request(cmd, -EIO, this_count, 1); |
1da177e4 LT |
981 | return; |
982 | default: | |
983 | break; | |
984 | } | |
03aba2f7 | 985 | } |
1da177e4 | 986 | if (host_byte(result) == DID_RESET) { |
03aba2f7 LT |
987 | /* Third party bus reset or reset for error recovery |
988 | * reasons. Just retry the request and see what | |
989 | * happens. | |
1da177e4 LT |
990 | */ |
991 | scsi_requeue_command(q, cmd); | |
992 | return; | |
993 | } | |
994 | if (result) { | |
4aff5e23 | 995 | if (!(req->cmd_flags & REQ_QUIET)) { |
a4d04a4c | 996 | scsi_print_result(cmd); |
3173d8c3 JB |
997 | if (driver_byte(result) & DRIVER_SENSE) |
998 | scsi_print_sense("", cmd); | |
999 | } | |
1da177e4 | 1000 | } |
610d8b0c | 1001 | scsi_end_request(cmd, -EIO, this_count, !result); |
1da177e4 | 1002 | } |
1da177e4 | 1003 | |
6f9a35e2 BH |
1004 | static int scsi_init_sgtable(struct request *req, struct scsi_data_buffer *sdb, |
1005 | gfp_t gfp_mask) | |
1da177e4 | 1006 | { |
6f9a35e2 | 1007 | int count; |
1da177e4 LT |
1008 | |
1009 | /* | |
3b003157 | 1010 | * If sg table allocation fails, requeue request later. |
1da177e4 | 1011 | */ |
30b0c37b BH |
1012 | if (unlikely(scsi_alloc_sgtable(sdb, req->nr_phys_segments, |
1013 | gfp_mask))) { | |
1da177e4 | 1014 | return BLKPREP_DEFER; |
7c72ce81 | 1015 | } |
1da177e4 | 1016 | |
3b003157 | 1017 | req->buffer = NULL; |
1da177e4 | 1018 | if (blk_pc_request(req)) |
30b0c37b | 1019 | sdb->length = req->data_len; |
3b003157 | 1020 | else |
30b0c37b | 1021 | sdb->length = req->nr_sectors << 9; |
1da177e4 LT |
1022 | |
1023 | /* | |
1024 | * Next, walk the list, and fill in the addresses and sizes of | |
1025 | * each segment. | |
1026 | */ | |
30b0c37b BH |
1027 | count = blk_rq_map_sg(req->q, req, sdb->table.sgl); |
1028 | BUG_ON(count > sdb->table.nents); | |
1029 | sdb->table.nents = count; | |
4a03d90e | 1030 | return BLKPREP_OK; |
1da177e4 | 1031 | } |
6f9a35e2 BH |
1032 | |
1033 | /* | |
1034 | * Function: scsi_init_io() | |
1035 | * | |
1036 | * Purpose: SCSI I/O initialize function. | |
1037 | * | |
1038 | * Arguments: cmd - Command descriptor we wish to initialize | |
1039 | * | |
1040 | * Returns: 0 on success | |
1041 | * BLKPREP_DEFER if the failure is retryable | |
1042 | * BLKPREP_KILL if the failure is fatal | |
1043 | */ | |
1044 | int scsi_init_io(struct scsi_cmnd *cmd, gfp_t gfp_mask) | |
1045 | { | |
1046 | int error = scsi_init_sgtable(cmd->request, &cmd->sdb, gfp_mask); | |
1047 | if (error) | |
1048 | goto err_exit; | |
1049 | ||
1050 | if (blk_bidi_rq(cmd->request)) { | |
1051 | struct scsi_data_buffer *bidi_sdb = kmem_cache_zalloc( | |
1052 | scsi_bidi_sdb_cache, GFP_ATOMIC); | |
1053 | if (!bidi_sdb) { | |
1054 | error = BLKPREP_DEFER; | |
1055 | goto err_exit; | |
1056 | } | |
1057 | ||
1058 | cmd->request->next_rq->special = bidi_sdb; | |
1059 | error = scsi_init_sgtable(cmd->request->next_rq, bidi_sdb, | |
1060 | GFP_ATOMIC); | |
1061 | if (error) | |
1062 | goto err_exit; | |
1063 | } | |
1064 | ||
1065 | return BLKPREP_OK ; | |
1066 | ||
1067 | err_exit: | |
1068 | scsi_release_buffers(cmd); | |
1069 | if (error == BLKPREP_KILL) | |
1070 | scsi_put_command(cmd); | |
1071 | else /* BLKPREP_DEFER */ | |
1072 | scsi_unprep_request(cmd->request); | |
1073 | ||
1074 | return error; | |
1075 | } | |
bb52d82f | 1076 | EXPORT_SYMBOL(scsi_init_io); |
1da177e4 | 1077 | |
3b003157 CH |
1078 | static struct scsi_cmnd *scsi_get_cmd_from_req(struct scsi_device *sdev, |
1079 | struct request *req) | |
1080 | { | |
1081 | struct scsi_cmnd *cmd; | |
1082 | ||
1083 | if (!req->special) { | |
1084 | cmd = scsi_get_command(sdev, GFP_ATOMIC); | |
1085 | if (unlikely(!cmd)) | |
1086 | return NULL; | |
1087 | req->special = cmd; | |
1088 | } else { | |
1089 | cmd = req->special; | |
1090 | } | |
1091 | ||
1092 | /* pull a tag out of the request if we have one */ | |
1093 | cmd->tag = req->tag; | |
1094 | cmd->request = req; | |
1095 | ||
1096 | return cmd; | |
1097 | } | |
1098 | ||
7f9a6bc4 | 1099 | int scsi_setup_blk_pc_cmnd(struct scsi_device *sdev, struct request *req) |
7b16318d | 1100 | { |
3b003157 | 1101 | struct scsi_cmnd *cmd; |
7f9a6bc4 JB |
1102 | int ret = scsi_prep_state_check(sdev, req); |
1103 | ||
1104 | if (ret != BLKPREP_OK) | |
1105 | return ret; | |
3b003157 CH |
1106 | |
1107 | cmd = scsi_get_cmd_from_req(sdev, req); | |
1108 | if (unlikely(!cmd)) | |
1109 | return BLKPREP_DEFER; | |
1110 | ||
1111 | /* | |
1112 | * BLOCK_PC requests may transfer data, in which case they must | |
1113 | * a bio attached to them. Or they might contain a SCSI command | |
1114 | * that does not transfer data, in which case they may optionally | |
1115 | * submit a request without an attached bio. | |
1116 | */ | |
1117 | if (req->bio) { | |
1118 | int ret; | |
1119 | ||
1120 | BUG_ON(!req->nr_phys_segments); | |
1121 | ||
bb52d82f | 1122 | ret = scsi_init_io(cmd, GFP_ATOMIC); |
3b003157 CH |
1123 | if (unlikely(ret)) |
1124 | return ret; | |
1125 | } else { | |
1126 | BUG_ON(req->data_len); | |
1127 | BUG_ON(req->data); | |
1128 | ||
30b0c37b | 1129 | memset(&cmd->sdb, 0, sizeof(cmd->sdb)); |
3b003157 CH |
1130 | req->buffer = NULL; |
1131 | } | |
7b16318d | 1132 | |
46c43db1 | 1133 | BUILD_BUG_ON(sizeof(req->cmd) > sizeof(cmd->cmnd)); |
7b16318d JB |
1134 | memcpy(cmd->cmnd, req->cmd, sizeof(cmd->cmnd)); |
1135 | cmd->cmd_len = req->cmd_len; | |
1136 | if (!req->data_len) | |
1137 | cmd->sc_data_direction = DMA_NONE; | |
1138 | else if (rq_data_dir(req) == WRITE) | |
1139 | cmd->sc_data_direction = DMA_TO_DEVICE; | |
1140 | else | |
1141 | cmd->sc_data_direction = DMA_FROM_DEVICE; | |
1142 | ||
1143 | cmd->transfersize = req->data_len; | |
1144 | cmd->allowed = req->retries; | |
1145 | cmd->timeout_per_command = req->timeout; | |
3b003157 | 1146 | return BLKPREP_OK; |
7b16318d | 1147 | } |
7f9a6bc4 | 1148 | EXPORT_SYMBOL(scsi_setup_blk_pc_cmnd); |
7b16318d | 1149 | |
3b003157 CH |
1150 | /* |
1151 | * Setup a REQ_TYPE_FS command. These are simple read/write request | |
1152 | * from filesystems that still need to be translated to SCSI CDBs from | |
1153 | * the ULD. | |
1154 | */ | |
7f9a6bc4 | 1155 | int scsi_setup_fs_cmnd(struct scsi_device *sdev, struct request *req) |
1da177e4 | 1156 | { |
1da177e4 | 1157 | struct scsi_cmnd *cmd; |
7f9a6bc4 | 1158 | int ret = scsi_prep_state_check(sdev, req); |
1da177e4 | 1159 | |
7f9a6bc4 JB |
1160 | if (ret != BLKPREP_OK) |
1161 | return ret; | |
1da177e4 | 1162 | /* |
3b003157 | 1163 | * Filesystem requests must transfer data. |
1da177e4 | 1164 | */ |
3b003157 CH |
1165 | BUG_ON(!req->nr_phys_segments); |
1166 | ||
1167 | cmd = scsi_get_cmd_from_req(sdev, req); | |
1168 | if (unlikely(!cmd)) | |
1169 | return BLKPREP_DEFER; | |
1170 | ||
bb52d82f | 1171 | return scsi_init_io(cmd, GFP_ATOMIC); |
3b003157 | 1172 | } |
7f9a6bc4 | 1173 | EXPORT_SYMBOL(scsi_setup_fs_cmnd); |
3b003157 | 1174 | |
7f9a6bc4 | 1175 | int scsi_prep_state_check(struct scsi_device *sdev, struct request *req) |
3b003157 | 1176 | { |
3b003157 CH |
1177 | int ret = BLKPREP_OK; |
1178 | ||
1da177e4 | 1179 | /* |
3b003157 CH |
1180 | * If the device is not in running state we will reject some |
1181 | * or all commands. | |
1da177e4 | 1182 | */ |
3b003157 CH |
1183 | if (unlikely(sdev->sdev_state != SDEV_RUNNING)) { |
1184 | switch (sdev->sdev_state) { | |
1185 | case SDEV_OFFLINE: | |
1186 | /* | |
1187 | * If the device is offline we refuse to process any | |
1188 | * commands. The device must be brought online | |
1189 | * before trying any recovery commands. | |
1190 | */ | |
1191 | sdev_printk(KERN_ERR, sdev, | |
1192 | "rejecting I/O to offline device\n"); | |
1193 | ret = BLKPREP_KILL; | |
1194 | break; | |
1195 | case SDEV_DEL: | |
1196 | /* | |
1197 | * If the device is fully deleted, we refuse to | |
1198 | * process any commands as well. | |
1199 | */ | |
9ccfc756 | 1200 | sdev_printk(KERN_ERR, sdev, |
3b003157 CH |
1201 | "rejecting I/O to dead device\n"); |
1202 | ret = BLKPREP_KILL; | |
1203 | break; | |
1204 | case SDEV_QUIESCE: | |
1205 | case SDEV_BLOCK: | |
1206 | /* | |
1207 | * If the devices is blocked we defer normal commands. | |
1208 | */ | |
1209 | if (!(req->cmd_flags & REQ_PREEMPT)) | |
1210 | ret = BLKPREP_DEFER; | |
1211 | break; | |
1212 | default: | |
1213 | /* | |
1214 | * For any other not fully online state we only allow | |
1215 | * special commands. In particular any user initiated | |
1216 | * command is not allowed. | |
1217 | */ | |
1218 | if (!(req->cmd_flags & REQ_PREEMPT)) | |
1219 | ret = BLKPREP_KILL; | |
1220 | break; | |
1da177e4 | 1221 | } |
1da177e4 | 1222 | } |
7f9a6bc4 JB |
1223 | return ret; |
1224 | } | |
1225 | EXPORT_SYMBOL(scsi_prep_state_check); | |
1da177e4 | 1226 | |
7f9a6bc4 JB |
1227 | int scsi_prep_return(struct request_queue *q, struct request *req, int ret) |
1228 | { | |
1229 | struct scsi_device *sdev = q->queuedata; | |
1da177e4 | 1230 | |
3b003157 CH |
1231 | switch (ret) { |
1232 | case BLKPREP_KILL: | |
1233 | req->errors = DID_NO_CONNECT << 16; | |
7f9a6bc4 JB |
1234 | /* release the command and kill it */ |
1235 | if (req->special) { | |
1236 | struct scsi_cmnd *cmd = req->special; | |
1237 | scsi_release_buffers(cmd); | |
1238 | scsi_put_command(cmd); | |
1239 | req->special = NULL; | |
1240 | } | |
3b003157 CH |
1241 | break; |
1242 | case BLKPREP_DEFER: | |
1da177e4 | 1243 | /* |
3b003157 CH |
1244 | * If we defer, the elv_next_request() returns NULL, but the |
1245 | * queue must be restarted, so we plug here if no returning | |
1246 | * command will automatically do that. | |
1da177e4 | 1247 | */ |
3b003157 CH |
1248 | if (sdev->device_busy == 0) |
1249 | blk_plug_device(q); | |
1250 | break; | |
1251 | default: | |
1252 | req->cmd_flags |= REQ_DONTPREP; | |
1da177e4 LT |
1253 | } |
1254 | ||
3b003157 | 1255 | return ret; |
1da177e4 | 1256 | } |
7f9a6bc4 JB |
1257 | EXPORT_SYMBOL(scsi_prep_return); |
1258 | ||
751bf4d7 | 1259 | int scsi_prep_fn(struct request_queue *q, struct request *req) |
7f9a6bc4 JB |
1260 | { |
1261 | struct scsi_device *sdev = q->queuedata; | |
1262 | int ret = BLKPREP_KILL; | |
1263 | ||
1264 | if (req->cmd_type == REQ_TYPE_BLOCK_PC) | |
1265 | ret = scsi_setup_blk_pc_cmnd(sdev, req); | |
1266 | return scsi_prep_return(q, req, ret); | |
1267 | } | |
1da177e4 LT |
1268 | |
1269 | /* | |
1270 | * scsi_dev_queue_ready: if we can send requests to sdev, return 1 else | |
1271 | * return 0. | |
1272 | * | |
1273 | * Called with the queue_lock held. | |
1274 | */ | |
1275 | static inline int scsi_dev_queue_ready(struct request_queue *q, | |
1276 | struct scsi_device *sdev) | |
1277 | { | |
1278 | if (sdev->device_busy >= sdev->queue_depth) | |
1279 | return 0; | |
1280 | if (sdev->device_busy == 0 && sdev->device_blocked) { | |
1281 | /* | |
1282 | * unblock after device_blocked iterates to zero | |
1283 | */ | |
1284 | if (--sdev->device_blocked == 0) { | |
1285 | SCSI_LOG_MLQUEUE(3, | |
9ccfc756 JB |
1286 | sdev_printk(KERN_INFO, sdev, |
1287 | "unblocking device at zero depth\n")); | |
1da177e4 LT |
1288 | } else { |
1289 | blk_plug_device(q); | |
1290 | return 0; | |
1291 | } | |
1292 | } | |
1293 | if (sdev->device_blocked) | |
1294 | return 0; | |
1295 | ||
1296 | return 1; | |
1297 | } | |
1298 | ||
1299 | /* | |
1300 | * scsi_host_queue_ready: if we can send requests to shost, return 1 else | |
1301 | * return 0. We must end up running the queue again whenever 0 is | |
1302 | * returned, else IO can hang. | |
1303 | * | |
1304 | * Called with host_lock held. | |
1305 | */ | |
1306 | static inline int scsi_host_queue_ready(struct request_queue *q, | |
1307 | struct Scsi_Host *shost, | |
1308 | struct scsi_device *sdev) | |
1309 | { | |
939647ee | 1310 | if (scsi_host_in_recovery(shost)) |
1da177e4 LT |
1311 | return 0; |
1312 | if (shost->host_busy == 0 && shost->host_blocked) { | |
1313 | /* | |
1314 | * unblock after host_blocked iterates to zero | |
1315 | */ | |
1316 | if (--shost->host_blocked == 0) { | |
1317 | SCSI_LOG_MLQUEUE(3, | |
1318 | printk("scsi%d unblocking host at zero depth\n", | |
1319 | shost->host_no)); | |
1320 | } else { | |
1321 | blk_plug_device(q); | |
1322 | return 0; | |
1323 | } | |
1324 | } | |
1325 | if ((shost->can_queue > 0 && shost->host_busy >= shost->can_queue) || | |
1326 | shost->host_blocked || shost->host_self_blocked) { | |
1327 | if (list_empty(&sdev->starved_entry)) | |
1328 | list_add_tail(&sdev->starved_entry, &shost->starved_list); | |
1329 | return 0; | |
1330 | } | |
1331 | ||
1332 | /* We're OK to process the command, so we can't be starved */ | |
1333 | if (!list_empty(&sdev->starved_entry)) | |
1334 | list_del_init(&sdev->starved_entry); | |
1335 | ||
1336 | return 1; | |
1337 | } | |
1338 | ||
1339 | /* | |
e91442b6 | 1340 | * Kill a request for a dead device |
1da177e4 | 1341 | */ |
165125e1 | 1342 | static void scsi_kill_request(struct request *req, struct request_queue *q) |
1da177e4 | 1343 | { |
e91442b6 | 1344 | struct scsi_cmnd *cmd = req->special; |
e36e0c80 TH |
1345 | struct scsi_device *sdev = cmd->device; |
1346 | struct Scsi_Host *shost = sdev->host; | |
1da177e4 | 1347 | |
788ce43a JB |
1348 | blkdev_dequeue_request(req); |
1349 | ||
e91442b6 JB |
1350 | if (unlikely(cmd == NULL)) { |
1351 | printk(KERN_CRIT "impossible request in %s.\n", | |
1352 | __FUNCTION__); | |
1353 | BUG(); | |
1da177e4 | 1354 | } |
e91442b6 JB |
1355 | |
1356 | scsi_init_cmd_errh(cmd); | |
1357 | cmd->result = DID_NO_CONNECT << 16; | |
1358 | atomic_inc(&cmd->device->iorequest_cnt); | |
e36e0c80 TH |
1359 | |
1360 | /* | |
1361 | * SCSI request completion path will do scsi_device_unbusy(), | |
1362 | * bump busy counts. To bump the counters, we need to dance | |
1363 | * with the locks as normal issue path does. | |
1364 | */ | |
1365 | sdev->device_busy++; | |
1366 | spin_unlock(sdev->request_queue->queue_lock); | |
1367 | spin_lock(shost->host_lock); | |
1368 | shost->host_busy++; | |
1369 | spin_unlock(shost->host_lock); | |
1370 | spin_lock(sdev->request_queue->queue_lock); | |
1371 | ||
e91442b6 | 1372 | __scsi_done(cmd); |
1da177e4 LT |
1373 | } |
1374 | ||
1aea6434 JA |
1375 | static void scsi_softirq_done(struct request *rq) |
1376 | { | |
1377 | struct scsi_cmnd *cmd = rq->completion_data; | |
8884efab | 1378 | unsigned long wait_for = (cmd->allowed + 1) * cmd->timeout_per_command; |
1aea6434 JA |
1379 | int disposition; |
1380 | ||
1381 | INIT_LIST_HEAD(&cmd->eh_entry); | |
1382 | ||
1383 | disposition = scsi_decide_disposition(cmd); | |
1384 | if (disposition != SUCCESS && | |
1385 | time_before(cmd->jiffies_at_alloc + wait_for, jiffies)) { | |
1386 | sdev_printk(KERN_ERR, cmd->device, | |
1387 | "timing out command, waited %lus\n", | |
1388 | wait_for/HZ); | |
1389 | disposition = SUCCESS; | |
1390 | } | |
1391 | ||
1392 | scsi_log_completion(cmd, disposition); | |
1393 | ||
1394 | switch (disposition) { | |
1395 | case SUCCESS: | |
1396 | scsi_finish_command(cmd); | |
1397 | break; | |
1398 | case NEEDS_RETRY: | |
596f482a | 1399 | scsi_queue_insert(cmd, SCSI_MLQUEUE_EH_RETRY); |
1aea6434 JA |
1400 | break; |
1401 | case ADD_TO_MLQUEUE: | |
1402 | scsi_queue_insert(cmd, SCSI_MLQUEUE_DEVICE_BUSY); | |
1403 | break; | |
1404 | default: | |
1405 | if (!scsi_eh_scmd_add(cmd, 0)) | |
1406 | scsi_finish_command(cmd); | |
1407 | } | |
1408 | } | |
1409 | ||
1da177e4 LT |
1410 | /* |
1411 | * Function: scsi_request_fn() | |
1412 | * | |
1413 | * Purpose: Main strategy routine for SCSI. | |
1414 | * | |
1415 | * Arguments: q - Pointer to actual queue. | |
1416 | * | |
1417 | * Returns: Nothing | |
1418 | * | |
1419 | * Lock status: IO request lock assumed to be held when called. | |
1420 | */ | |
1421 | static void scsi_request_fn(struct request_queue *q) | |
1422 | { | |
1423 | struct scsi_device *sdev = q->queuedata; | |
1424 | struct Scsi_Host *shost; | |
1425 | struct scsi_cmnd *cmd; | |
1426 | struct request *req; | |
1427 | ||
1428 | if (!sdev) { | |
1429 | printk("scsi: killing requests for dead queue\n"); | |
e91442b6 JB |
1430 | while ((req = elv_next_request(q)) != NULL) |
1431 | scsi_kill_request(req, q); | |
1da177e4 LT |
1432 | return; |
1433 | } | |
1434 | ||
1435 | if(!get_device(&sdev->sdev_gendev)) | |
1436 | /* We must be tearing the block queue down already */ | |
1437 | return; | |
1438 | ||
1439 | /* | |
1440 | * To start with, we keep looping until the queue is empty, or until | |
1441 | * the host is no longer able to accept any more requests. | |
1442 | */ | |
1443 | shost = sdev->host; | |
1444 | while (!blk_queue_plugged(q)) { | |
1445 | int rtn; | |
1446 | /* | |
1447 | * get next queueable request. We do this early to make sure | |
1448 | * that the request is fully prepared even if we cannot | |
1449 | * accept it. | |
1450 | */ | |
1451 | req = elv_next_request(q); | |
1452 | if (!req || !scsi_dev_queue_ready(q, sdev)) | |
1453 | break; | |
1454 | ||
1455 | if (unlikely(!scsi_device_online(sdev))) { | |
9ccfc756 JB |
1456 | sdev_printk(KERN_ERR, sdev, |
1457 | "rejecting I/O to offline device\n"); | |
e91442b6 | 1458 | scsi_kill_request(req, q); |
1da177e4 LT |
1459 | continue; |
1460 | } | |
1461 | ||
1462 | ||
1463 | /* | |
1464 | * Remove the request from the request list. | |
1465 | */ | |
1466 | if (!(blk_queue_tagged(q) && !blk_queue_start_tag(q, req))) | |
1467 | blkdev_dequeue_request(req); | |
1468 | sdev->device_busy++; | |
1469 | ||
1470 | spin_unlock(q->queue_lock); | |
e91442b6 JB |
1471 | cmd = req->special; |
1472 | if (unlikely(cmd == NULL)) { | |
1473 | printk(KERN_CRIT "impossible request in %s.\n" | |
1474 | "please mail a stack trace to " | |
4aff5e23 | 1475 | "linux-scsi@vger.kernel.org\n", |
e91442b6 | 1476 | __FUNCTION__); |
4aff5e23 | 1477 | blk_dump_rq_flags(req, "foo"); |
e91442b6 JB |
1478 | BUG(); |
1479 | } | |
1da177e4 LT |
1480 | spin_lock(shost->host_lock); |
1481 | ||
1482 | if (!scsi_host_queue_ready(q, shost, sdev)) | |
1483 | goto not_ready; | |
25d7c363 | 1484 | if (scsi_target(sdev)->single_lun) { |
1da177e4 LT |
1485 | if (scsi_target(sdev)->starget_sdev_user && |
1486 | scsi_target(sdev)->starget_sdev_user != sdev) | |
1487 | goto not_ready; | |
1488 | scsi_target(sdev)->starget_sdev_user = sdev; | |
1489 | } | |
1490 | shost->host_busy++; | |
1491 | ||
1492 | /* | |
1493 | * XXX(hch): This is rather suboptimal, scsi_dispatch_cmd will | |
1494 | * take the lock again. | |
1495 | */ | |
1496 | spin_unlock_irq(shost->host_lock); | |
1497 | ||
1da177e4 LT |
1498 | /* |
1499 | * Finally, initialize any error handling parameters, and set up | |
1500 | * the timers for timeouts. | |
1501 | */ | |
1502 | scsi_init_cmd_errh(cmd); | |
1503 | ||
1504 | /* | |
1505 | * Dispatch the command to the low-level driver. | |
1506 | */ | |
1507 | rtn = scsi_dispatch_cmd(cmd); | |
1508 | spin_lock_irq(q->queue_lock); | |
1509 | if(rtn) { | |
1510 | /* we're refusing the command; because of | |
1511 | * the way locks get dropped, we need to | |
1512 | * check here if plugging is required */ | |
1513 | if(sdev->device_busy == 0) | |
1514 | blk_plug_device(q); | |
1515 | ||
1516 | break; | |
1517 | } | |
1518 | } | |
1519 | ||
1520 | goto out; | |
1521 | ||
1522 | not_ready: | |
1523 | spin_unlock_irq(shost->host_lock); | |
1524 | ||
1525 | /* | |
1526 | * lock q, handle tag, requeue req, and decrement device_busy. We | |
1527 | * must return with queue_lock held. | |
1528 | * | |
1529 | * Decrementing device_busy without checking it is OK, as all such | |
1530 | * cases (host limits or settings) should run the queue at some | |
1531 | * later time. | |
1532 | */ | |
1533 | spin_lock_irq(q->queue_lock); | |
1534 | blk_requeue_request(q, req); | |
1535 | sdev->device_busy--; | |
1536 | if(sdev->device_busy == 0) | |
1537 | blk_plug_device(q); | |
1538 | out: | |
1539 | /* must be careful here...if we trigger the ->remove() function | |
1540 | * we cannot be holding the q lock */ | |
1541 | spin_unlock_irq(q->queue_lock); | |
1542 | put_device(&sdev->sdev_gendev); | |
1543 | spin_lock_irq(q->queue_lock); | |
1544 | } | |
1545 | ||
1546 | u64 scsi_calculate_bounce_limit(struct Scsi_Host *shost) | |
1547 | { | |
1548 | struct device *host_dev; | |
1549 | u64 bounce_limit = 0xffffffff; | |
1550 | ||
1551 | if (shost->unchecked_isa_dma) | |
1552 | return BLK_BOUNCE_ISA; | |
1553 | /* | |
1554 | * Platforms with virtual-DMA translation | |
1555 | * hardware have no practical limit. | |
1556 | */ | |
1557 | if (!PCI_DMA_BUS_IS_PHYS) | |
1558 | return BLK_BOUNCE_ANY; | |
1559 | ||
1560 | host_dev = scsi_get_device(shost); | |
1561 | if (host_dev && host_dev->dma_mask) | |
1562 | bounce_limit = *host_dev->dma_mask; | |
1563 | ||
1564 | return bounce_limit; | |
1565 | } | |
1566 | EXPORT_SYMBOL(scsi_calculate_bounce_limit); | |
1567 | ||
b58d9154 FT |
1568 | struct request_queue *__scsi_alloc_queue(struct Scsi_Host *shost, |
1569 | request_fn_proc *request_fn) | |
1da177e4 | 1570 | { |
1da177e4 | 1571 | struct request_queue *q; |
860ac568 | 1572 | struct device *dev = shost->shost_gendev.parent; |
1da177e4 | 1573 | |
b58d9154 | 1574 | q = blk_init_queue(request_fn, NULL); |
1da177e4 LT |
1575 | if (!q) |
1576 | return NULL; | |
1577 | ||
a8474ce2 JA |
1578 | /* |
1579 | * this limit is imposed by hardware restrictions | |
1580 | */ | |
1da177e4 | 1581 | blk_queue_max_hw_segments(q, shost->sg_tablesize); |
d3f46f39 | 1582 | blk_queue_max_phys_segments(q, SCSI_MAX_SG_CHAIN_SEGMENTS); |
a8474ce2 | 1583 | |
1da177e4 LT |
1584 | blk_queue_max_sectors(q, shost->max_sectors); |
1585 | blk_queue_bounce_limit(q, scsi_calculate_bounce_limit(shost)); | |
1586 | blk_queue_segment_boundary(q, shost->dma_boundary); | |
1da177e4 | 1587 | |
860ac568 FT |
1588 | blk_queue_max_segment_size(q, dma_get_max_seg_size(dev)); |
1589 | ||
1da177e4 LT |
1590 | if (!shost->use_clustering) |
1591 | clear_bit(QUEUE_FLAG_CLUSTER, &q->queue_flags); | |
465ff318 JB |
1592 | |
1593 | /* | |
1594 | * set a reasonable default alignment on word boundaries: the | |
1595 | * host and device may alter it using | |
1596 | * blk_queue_update_dma_alignment() later. | |
1597 | */ | |
1598 | blk_queue_dma_alignment(q, 0x03); | |
1599 | ||
1da177e4 LT |
1600 | return q; |
1601 | } | |
b58d9154 FT |
1602 | EXPORT_SYMBOL(__scsi_alloc_queue); |
1603 | ||
1604 | struct request_queue *scsi_alloc_queue(struct scsi_device *sdev) | |
1605 | { | |
1606 | struct request_queue *q; | |
1607 | ||
1608 | q = __scsi_alloc_queue(sdev->host, scsi_request_fn); | |
1609 | if (!q) | |
1610 | return NULL; | |
1611 | ||
1612 | blk_queue_prep_rq(q, scsi_prep_fn); | |
b58d9154 FT |
1613 | blk_queue_softirq_done(q, scsi_softirq_done); |
1614 | return q; | |
1615 | } | |
1da177e4 LT |
1616 | |
1617 | void scsi_free_queue(struct request_queue *q) | |
1618 | { | |
1619 | blk_cleanup_queue(q); | |
1620 | } | |
1621 | ||
1622 | /* | |
1623 | * Function: scsi_block_requests() | |
1624 | * | |
1625 | * Purpose: Utility function used by low-level drivers to prevent further | |
1626 | * commands from being queued to the device. | |
1627 | * | |
1628 | * Arguments: shost - Host in question | |
1629 | * | |
1630 | * Returns: Nothing | |
1631 | * | |
1632 | * Lock status: No locks are assumed held. | |
1633 | * | |
1634 | * Notes: There is no timer nor any other means by which the requests | |
1635 | * get unblocked other than the low-level driver calling | |
1636 | * scsi_unblock_requests(). | |
1637 | */ | |
1638 | void scsi_block_requests(struct Scsi_Host *shost) | |
1639 | { | |
1640 | shost->host_self_blocked = 1; | |
1641 | } | |
1642 | EXPORT_SYMBOL(scsi_block_requests); | |
1643 | ||
1644 | /* | |
1645 | * Function: scsi_unblock_requests() | |
1646 | * | |
1647 | * Purpose: Utility function used by low-level drivers to allow further | |
1648 | * commands from being queued to the device. | |
1649 | * | |
1650 | * Arguments: shost - Host in question | |
1651 | * | |
1652 | * Returns: Nothing | |
1653 | * | |
1654 | * Lock status: No locks are assumed held. | |
1655 | * | |
1656 | * Notes: There is no timer nor any other means by which the requests | |
1657 | * get unblocked other than the low-level driver calling | |
1658 | * scsi_unblock_requests(). | |
1659 | * | |
1660 | * This is done as an API function so that changes to the | |
1661 | * internals of the scsi mid-layer won't require wholesale | |
1662 | * changes to drivers that use this feature. | |
1663 | */ | |
1664 | void scsi_unblock_requests(struct Scsi_Host *shost) | |
1665 | { | |
1666 | shost->host_self_blocked = 0; | |
1667 | scsi_run_host_queues(shost); | |
1668 | } | |
1669 | EXPORT_SYMBOL(scsi_unblock_requests); | |
1670 | ||
1671 | int __init scsi_init_queue(void) | |
1672 | { | |
1673 | int i; | |
1674 | ||
aa7b5cd7 MC |
1675 | scsi_io_context_cache = kmem_cache_create("scsi_io_context", |
1676 | sizeof(struct scsi_io_context), | |
20c2df83 | 1677 | 0, 0, NULL); |
aa7b5cd7 MC |
1678 | if (!scsi_io_context_cache) { |
1679 | printk(KERN_ERR "SCSI: can't init scsi io context cache\n"); | |
1680 | return -ENOMEM; | |
1681 | } | |
1682 | ||
6f9a35e2 BH |
1683 | scsi_bidi_sdb_cache = kmem_cache_create("scsi_bidi_sdb", |
1684 | sizeof(struct scsi_data_buffer), | |
1685 | 0, 0, NULL); | |
1686 | if (!scsi_bidi_sdb_cache) { | |
1687 | printk(KERN_ERR "SCSI: can't init scsi bidi sdb cache\n"); | |
3d9dd6ee | 1688 | goto cleanup_io_context; |
6f9a35e2 BH |
1689 | } |
1690 | ||
1da177e4 LT |
1691 | for (i = 0; i < SG_MEMPOOL_NR; i++) { |
1692 | struct scsi_host_sg_pool *sgp = scsi_sg_pools + i; | |
1693 | int size = sgp->size * sizeof(struct scatterlist); | |
1694 | ||
1695 | sgp->slab = kmem_cache_create(sgp->name, size, 0, | |
20c2df83 | 1696 | SLAB_HWCACHE_ALIGN, NULL); |
1da177e4 LT |
1697 | if (!sgp->slab) { |
1698 | printk(KERN_ERR "SCSI: can't init sg slab %s\n", | |
1699 | sgp->name); | |
3d9dd6ee | 1700 | goto cleanup_bidi_sdb; |
1da177e4 LT |
1701 | } |
1702 | ||
93d2341c MD |
1703 | sgp->pool = mempool_create_slab_pool(SG_MEMPOOL_SIZE, |
1704 | sgp->slab); | |
1da177e4 LT |
1705 | if (!sgp->pool) { |
1706 | printk(KERN_ERR "SCSI: can't init sg mempool %s\n", | |
1707 | sgp->name); | |
3d9dd6ee | 1708 | goto cleanup_bidi_sdb; |
1da177e4 LT |
1709 | } |
1710 | } | |
1711 | ||
1712 | return 0; | |
3d9dd6ee FT |
1713 | |
1714 | cleanup_bidi_sdb: | |
1715 | for (i = 0; i < SG_MEMPOOL_NR; i++) { | |
1716 | struct scsi_host_sg_pool *sgp = scsi_sg_pools + i; | |
1717 | if (sgp->pool) | |
1718 | mempool_destroy(sgp->pool); | |
1719 | if (sgp->slab) | |
1720 | kmem_cache_destroy(sgp->slab); | |
1721 | } | |
1722 | kmem_cache_destroy(scsi_bidi_sdb_cache); | |
1723 | cleanup_io_context: | |
1724 | kmem_cache_destroy(scsi_io_context_cache); | |
1725 | ||
1726 | return -ENOMEM; | |
1da177e4 LT |
1727 | } |
1728 | ||
1729 | void scsi_exit_queue(void) | |
1730 | { | |
1731 | int i; | |
1732 | ||
aa7b5cd7 | 1733 | kmem_cache_destroy(scsi_io_context_cache); |
b172b6e9 | 1734 | kmem_cache_destroy(scsi_bidi_sdb_cache); |
aa7b5cd7 | 1735 | |
1da177e4 LT |
1736 | for (i = 0; i < SG_MEMPOOL_NR; i++) { |
1737 | struct scsi_host_sg_pool *sgp = scsi_sg_pools + i; | |
1738 | mempool_destroy(sgp->pool); | |
1739 | kmem_cache_destroy(sgp->slab); | |
1740 | } | |
1741 | } | |
5baba830 JB |
1742 | |
1743 | /** | |
1744 | * scsi_mode_select - issue a mode select | |
1745 | * @sdev: SCSI device to be queried | |
1746 | * @pf: Page format bit (1 == standard, 0 == vendor specific) | |
1747 | * @sp: Save page bit (0 == don't save, 1 == save) | |
1748 | * @modepage: mode page being requested | |
1749 | * @buffer: request buffer (may not be smaller than eight bytes) | |
1750 | * @len: length of request buffer. | |
1751 | * @timeout: command timeout | |
1752 | * @retries: number of retries before failing | |
1753 | * @data: returns a structure abstracting the mode header data | |
eb44820c | 1754 | * @sshdr: place to put sense data (or NULL if no sense to be collected). |
5baba830 JB |
1755 | * must be SCSI_SENSE_BUFFERSIZE big. |
1756 | * | |
1757 | * Returns zero if successful; negative error number or scsi | |
1758 | * status on error | |
1759 | * | |
1760 | */ | |
1761 | int | |
1762 | scsi_mode_select(struct scsi_device *sdev, int pf, int sp, int modepage, | |
1763 | unsigned char *buffer, int len, int timeout, int retries, | |
1764 | struct scsi_mode_data *data, struct scsi_sense_hdr *sshdr) | |
1765 | { | |
1766 | unsigned char cmd[10]; | |
1767 | unsigned char *real_buffer; | |
1768 | int ret; | |
1769 | ||
1770 | memset(cmd, 0, sizeof(cmd)); | |
1771 | cmd[1] = (pf ? 0x10 : 0) | (sp ? 0x01 : 0); | |
1772 | ||
1773 | if (sdev->use_10_for_ms) { | |
1774 | if (len > 65535) | |
1775 | return -EINVAL; | |
1776 | real_buffer = kmalloc(8 + len, GFP_KERNEL); | |
1777 | if (!real_buffer) | |
1778 | return -ENOMEM; | |
1779 | memcpy(real_buffer + 8, buffer, len); | |
1780 | len += 8; | |
1781 | real_buffer[0] = 0; | |
1782 | real_buffer[1] = 0; | |
1783 | real_buffer[2] = data->medium_type; | |
1784 | real_buffer[3] = data->device_specific; | |
1785 | real_buffer[4] = data->longlba ? 0x01 : 0; | |
1786 | real_buffer[5] = 0; | |
1787 | real_buffer[6] = data->block_descriptor_length >> 8; | |
1788 | real_buffer[7] = data->block_descriptor_length; | |
1789 | ||
1790 | cmd[0] = MODE_SELECT_10; | |
1791 | cmd[7] = len >> 8; | |
1792 | cmd[8] = len; | |
1793 | } else { | |
1794 | if (len > 255 || data->block_descriptor_length > 255 || | |
1795 | data->longlba) | |
1796 | return -EINVAL; | |
1797 | ||
1798 | real_buffer = kmalloc(4 + len, GFP_KERNEL); | |
1799 | if (!real_buffer) | |
1800 | return -ENOMEM; | |
1801 | memcpy(real_buffer + 4, buffer, len); | |
1802 | len += 4; | |
1803 | real_buffer[0] = 0; | |
1804 | real_buffer[1] = data->medium_type; | |
1805 | real_buffer[2] = data->device_specific; | |
1806 | real_buffer[3] = data->block_descriptor_length; | |
1807 | ||
1808 | ||
1809 | cmd[0] = MODE_SELECT; | |
1810 | cmd[4] = len; | |
1811 | } | |
1812 | ||
1813 | ret = scsi_execute_req(sdev, cmd, DMA_TO_DEVICE, real_buffer, len, | |
1814 | sshdr, timeout, retries); | |
1815 | kfree(real_buffer); | |
1816 | return ret; | |
1817 | } | |
1818 | EXPORT_SYMBOL_GPL(scsi_mode_select); | |
1819 | ||
1da177e4 | 1820 | /** |
eb44820c | 1821 | * scsi_mode_sense - issue a mode sense, falling back from 10 to six bytes if necessary. |
1cf72699 | 1822 | * @sdev: SCSI device to be queried |
1da177e4 LT |
1823 | * @dbd: set if mode sense will allow block descriptors to be returned |
1824 | * @modepage: mode page being requested | |
1825 | * @buffer: request buffer (may not be smaller than eight bytes) | |
1826 | * @len: length of request buffer. | |
1827 | * @timeout: command timeout | |
1828 | * @retries: number of retries before failing | |
1829 | * @data: returns a structure abstracting the mode header data | |
eb44820c | 1830 | * @sshdr: place to put sense data (or NULL if no sense to be collected). |
1cf72699 | 1831 | * must be SCSI_SENSE_BUFFERSIZE big. |
1da177e4 LT |
1832 | * |
1833 | * Returns zero if unsuccessful, or the header offset (either 4 | |
1834 | * or 8 depending on whether a six or ten byte command was | |
1835 | * issued) if successful. | |
eb44820c | 1836 | */ |
1da177e4 | 1837 | int |
1cf72699 | 1838 | scsi_mode_sense(struct scsi_device *sdev, int dbd, int modepage, |
1da177e4 | 1839 | unsigned char *buffer, int len, int timeout, int retries, |
5baba830 JB |
1840 | struct scsi_mode_data *data, struct scsi_sense_hdr *sshdr) |
1841 | { | |
1da177e4 LT |
1842 | unsigned char cmd[12]; |
1843 | int use_10_for_ms; | |
1844 | int header_length; | |
1cf72699 | 1845 | int result; |
ea73a9f2 | 1846 | struct scsi_sense_hdr my_sshdr; |
1da177e4 LT |
1847 | |
1848 | memset(data, 0, sizeof(*data)); | |
1849 | memset(&cmd[0], 0, 12); | |
1850 | cmd[1] = dbd & 0x18; /* allows DBD and LLBA bits */ | |
1851 | cmd[2] = modepage; | |
1852 | ||
ea73a9f2 JB |
1853 | /* caller might not be interested in sense, but we need it */ |
1854 | if (!sshdr) | |
1855 | sshdr = &my_sshdr; | |
1856 | ||
1da177e4 | 1857 | retry: |
1cf72699 | 1858 | use_10_for_ms = sdev->use_10_for_ms; |
1da177e4 LT |
1859 | |
1860 | if (use_10_for_ms) { | |
1861 | if (len < 8) | |
1862 | len = 8; | |
1863 | ||
1864 | cmd[0] = MODE_SENSE_10; | |
1865 | cmd[8] = len; | |
1866 | header_length = 8; | |
1867 | } else { | |
1868 | if (len < 4) | |
1869 | len = 4; | |
1870 | ||
1871 | cmd[0] = MODE_SENSE; | |
1872 | cmd[4] = len; | |
1873 | header_length = 4; | |
1874 | } | |
1875 | ||
1da177e4 LT |
1876 | memset(buffer, 0, len); |
1877 | ||
1cf72699 | 1878 | result = scsi_execute_req(sdev, cmd, DMA_FROM_DEVICE, buffer, len, |
ea73a9f2 | 1879 | sshdr, timeout, retries); |
1da177e4 LT |
1880 | |
1881 | /* This code looks awful: what it's doing is making sure an | |
1882 | * ILLEGAL REQUEST sense return identifies the actual command | |
1883 | * byte as the problem. MODE_SENSE commands can return | |
1884 | * ILLEGAL REQUEST if the code page isn't supported */ | |
1885 | ||
1cf72699 JB |
1886 | if (use_10_for_ms && !scsi_status_is_good(result) && |
1887 | (driver_byte(result) & DRIVER_SENSE)) { | |
ea73a9f2 JB |
1888 | if (scsi_sense_valid(sshdr)) { |
1889 | if ((sshdr->sense_key == ILLEGAL_REQUEST) && | |
1890 | (sshdr->asc == 0x20) && (sshdr->ascq == 0)) { | |
1da177e4 LT |
1891 | /* |
1892 | * Invalid command operation code | |
1893 | */ | |
1cf72699 | 1894 | sdev->use_10_for_ms = 0; |
1da177e4 LT |
1895 | goto retry; |
1896 | } | |
1897 | } | |
1898 | } | |
1899 | ||
1cf72699 | 1900 | if(scsi_status_is_good(result)) { |
6d73c851 AV |
1901 | if (unlikely(buffer[0] == 0x86 && buffer[1] == 0x0b && |
1902 | (modepage == 6 || modepage == 8))) { | |
1903 | /* Initio breakage? */ | |
1904 | header_length = 0; | |
1905 | data->length = 13; | |
1906 | data->medium_type = 0; | |
1907 | data->device_specific = 0; | |
1908 | data->longlba = 0; | |
1909 | data->block_descriptor_length = 0; | |
1910 | } else if(use_10_for_ms) { | |
1da177e4 LT |
1911 | data->length = buffer[0]*256 + buffer[1] + 2; |
1912 | data->medium_type = buffer[2]; | |
1913 | data->device_specific = buffer[3]; | |
1914 | data->longlba = buffer[4] & 0x01; | |
1915 | data->block_descriptor_length = buffer[6]*256 | |
1916 | + buffer[7]; | |
1917 | } else { | |
1918 | data->length = buffer[0] + 1; | |
1919 | data->medium_type = buffer[1]; | |
1920 | data->device_specific = buffer[2]; | |
1921 | data->block_descriptor_length = buffer[3]; | |
1922 | } | |
6d73c851 | 1923 | data->header_length = header_length; |
1da177e4 LT |
1924 | } |
1925 | ||
1cf72699 | 1926 | return result; |
1da177e4 LT |
1927 | } |
1928 | EXPORT_SYMBOL(scsi_mode_sense); | |
1929 | ||
001aac25 JB |
1930 | /** |
1931 | * scsi_test_unit_ready - test if unit is ready | |
1932 | * @sdev: scsi device to change the state of. | |
1933 | * @timeout: command timeout | |
1934 | * @retries: number of retries before failing | |
1935 | * @sshdr_external: Optional pointer to struct scsi_sense_hdr for | |
1936 | * returning sense. Make sure that this is cleared before passing | |
1937 | * in. | |
1938 | * | |
1939 | * Returns zero if unsuccessful or an error if TUR failed. For | |
1940 | * removable media, a return of NOT_READY or UNIT_ATTENTION is | |
1941 | * translated to success, with the ->changed flag updated. | |
1942 | **/ | |
1da177e4 | 1943 | int |
001aac25 JB |
1944 | scsi_test_unit_ready(struct scsi_device *sdev, int timeout, int retries, |
1945 | struct scsi_sense_hdr *sshdr_external) | |
1da177e4 | 1946 | { |
1da177e4 LT |
1947 | char cmd[] = { |
1948 | TEST_UNIT_READY, 0, 0, 0, 0, 0, | |
1949 | }; | |
001aac25 | 1950 | struct scsi_sense_hdr *sshdr; |
1da177e4 | 1951 | int result; |
001aac25 JB |
1952 | |
1953 | if (!sshdr_external) | |
1954 | sshdr = kzalloc(sizeof(*sshdr), GFP_KERNEL); | |
1955 | else | |
1956 | sshdr = sshdr_external; | |
1957 | ||
1958 | /* try to eat the UNIT_ATTENTION if there are enough retries */ | |
1959 | do { | |
1960 | result = scsi_execute_req(sdev, cmd, DMA_NONE, NULL, 0, sshdr, | |
1961 | timeout, retries); | |
1962 | } while ((driver_byte(result) & DRIVER_SENSE) && | |
1963 | sshdr && sshdr->sense_key == UNIT_ATTENTION && | |
1964 | --retries); | |
1965 | ||
1966 | if (!sshdr) | |
1967 | /* could not allocate sense buffer, so can't process it */ | |
1968 | return result; | |
1da177e4 | 1969 | |
1cf72699 | 1970 | if ((driver_byte(result) & DRIVER_SENSE) && sdev->removable) { |
1da177e4 | 1971 | |
001aac25 JB |
1972 | if ((scsi_sense_valid(sshdr)) && |
1973 | ((sshdr->sense_key == UNIT_ATTENTION) || | |
1974 | (sshdr->sense_key == NOT_READY))) { | |
1da177e4 | 1975 | sdev->changed = 1; |
1cf72699 | 1976 | result = 0; |
1da177e4 LT |
1977 | } |
1978 | } | |
001aac25 JB |
1979 | if (!sshdr_external) |
1980 | kfree(sshdr); | |
1da177e4 LT |
1981 | return result; |
1982 | } | |
1983 | EXPORT_SYMBOL(scsi_test_unit_ready); | |
1984 | ||
1985 | /** | |
eb44820c | 1986 | * scsi_device_set_state - Take the given device through the device state model. |
1da177e4 LT |
1987 | * @sdev: scsi device to change the state of. |
1988 | * @state: state to change to. | |
1989 | * | |
1990 | * Returns zero if unsuccessful or an error if the requested | |
1991 | * transition is illegal. | |
eb44820c | 1992 | */ |
1da177e4 LT |
1993 | int |
1994 | scsi_device_set_state(struct scsi_device *sdev, enum scsi_device_state state) | |
1995 | { | |
1996 | enum scsi_device_state oldstate = sdev->sdev_state; | |
1997 | ||
1998 | if (state == oldstate) | |
1999 | return 0; | |
2000 | ||
2001 | switch (state) { | |
2002 | case SDEV_CREATED: | |
2003 | /* There are no legal states that come back to | |
2004 | * created. This is the manually initialised start | |
2005 | * state */ | |
2006 | goto illegal; | |
2007 | ||
2008 | case SDEV_RUNNING: | |
2009 | switch (oldstate) { | |
2010 | case SDEV_CREATED: | |
2011 | case SDEV_OFFLINE: | |
2012 | case SDEV_QUIESCE: | |
2013 | case SDEV_BLOCK: | |
2014 | break; | |
2015 | default: | |
2016 | goto illegal; | |
2017 | } | |
2018 | break; | |
2019 | ||
2020 | case SDEV_QUIESCE: | |
2021 | switch (oldstate) { | |
2022 | case SDEV_RUNNING: | |
2023 | case SDEV_OFFLINE: | |
2024 | break; | |
2025 | default: | |
2026 | goto illegal; | |
2027 | } | |
2028 | break; | |
2029 | ||
2030 | case SDEV_OFFLINE: | |
2031 | switch (oldstate) { | |
2032 | case SDEV_CREATED: | |
2033 | case SDEV_RUNNING: | |
2034 | case SDEV_QUIESCE: | |
2035 | case SDEV_BLOCK: | |
2036 | break; | |
2037 | default: | |
2038 | goto illegal; | |
2039 | } | |
2040 | break; | |
2041 | ||
2042 | case SDEV_BLOCK: | |
2043 | switch (oldstate) { | |
2044 | case SDEV_CREATED: | |
2045 | case SDEV_RUNNING: | |
2046 | break; | |
2047 | default: | |
2048 | goto illegal; | |
2049 | } | |
2050 | break; | |
2051 | ||
2052 | case SDEV_CANCEL: | |
2053 | switch (oldstate) { | |
2054 | case SDEV_CREATED: | |
2055 | case SDEV_RUNNING: | |
9ea72909 | 2056 | case SDEV_QUIESCE: |
1da177e4 LT |
2057 | case SDEV_OFFLINE: |
2058 | case SDEV_BLOCK: | |
2059 | break; | |
2060 | default: | |
2061 | goto illegal; | |
2062 | } | |
2063 | break; | |
2064 | ||
2065 | case SDEV_DEL: | |
2066 | switch (oldstate) { | |
309bd271 BK |
2067 | case SDEV_CREATED: |
2068 | case SDEV_RUNNING: | |
2069 | case SDEV_OFFLINE: | |
1da177e4 LT |
2070 | case SDEV_CANCEL: |
2071 | break; | |
2072 | default: | |
2073 | goto illegal; | |
2074 | } | |
2075 | break; | |
2076 | ||
2077 | } | |
2078 | sdev->sdev_state = state; | |
2079 | return 0; | |
2080 | ||
2081 | illegal: | |
2082 | SCSI_LOG_ERROR_RECOVERY(1, | |
9ccfc756 JB |
2083 | sdev_printk(KERN_ERR, sdev, |
2084 | "Illegal state transition %s->%s\n", | |
2085 | scsi_device_state_name(oldstate), | |
2086 | scsi_device_state_name(state)) | |
1da177e4 LT |
2087 | ); |
2088 | return -EINVAL; | |
2089 | } | |
2090 | EXPORT_SYMBOL(scsi_device_set_state); | |
2091 | ||
a341cd0f JG |
2092 | /** |
2093 | * sdev_evt_emit - emit a single SCSI device uevent | |
2094 | * @sdev: associated SCSI device | |
2095 | * @evt: event to emit | |
2096 | * | |
2097 | * Send a single uevent (scsi_event) to the associated scsi_device. | |
2098 | */ | |
2099 | static void scsi_evt_emit(struct scsi_device *sdev, struct scsi_event *evt) | |
2100 | { | |
2101 | int idx = 0; | |
2102 | char *envp[3]; | |
2103 | ||
2104 | switch (evt->evt_type) { | |
2105 | case SDEV_EVT_MEDIA_CHANGE: | |
2106 | envp[idx++] = "SDEV_MEDIA_CHANGE=1"; | |
2107 | break; | |
2108 | ||
2109 | default: | |
2110 | /* do nothing */ | |
2111 | break; | |
2112 | } | |
2113 | ||
2114 | envp[idx++] = NULL; | |
2115 | ||
2116 | kobject_uevent_env(&sdev->sdev_gendev.kobj, KOBJ_CHANGE, envp); | |
2117 | } | |
2118 | ||
2119 | /** | |
2120 | * sdev_evt_thread - send a uevent for each scsi event | |
2121 | * @work: work struct for scsi_device | |
2122 | * | |
2123 | * Dispatch queued events to their associated scsi_device kobjects | |
2124 | * as uevents. | |
2125 | */ | |
2126 | void scsi_evt_thread(struct work_struct *work) | |
2127 | { | |
2128 | struct scsi_device *sdev; | |
2129 | LIST_HEAD(event_list); | |
2130 | ||
2131 | sdev = container_of(work, struct scsi_device, event_work); | |
2132 | ||
2133 | while (1) { | |
2134 | struct scsi_event *evt; | |
2135 | struct list_head *this, *tmp; | |
2136 | unsigned long flags; | |
2137 | ||
2138 | spin_lock_irqsave(&sdev->list_lock, flags); | |
2139 | list_splice_init(&sdev->event_list, &event_list); | |
2140 | spin_unlock_irqrestore(&sdev->list_lock, flags); | |
2141 | ||
2142 | if (list_empty(&event_list)) | |
2143 | break; | |
2144 | ||
2145 | list_for_each_safe(this, tmp, &event_list) { | |
2146 | evt = list_entry(this, struct scsi_event, node); | |
2147 | list_del(&evt->node); | |
2148 | scsi_evt_emit(sdev, evt); | |
2149 | kfree(evt); | |
2150 | } | |
2151 | } | |
2152 | } | |
2153 | ||
2154 | /** | |
2155 | * sdev_evt_send - send asserted event to uevent thread | |
2156 | * @sdev: scsi_device event occurred on | |
2157 | * @evt: event to send | |
2158 | * | |
2159 | * Assert scsi device event asynchronously. | |
2160 | */ | |
2161 | void sdev_evt_send(struct scsi_device *sdev, struct scsi_event *evt) | |
2162 | { | |
2163 | unsigned long flags; | |
2164 | ||
2165 | if (!test_bit(evt->evt_type, sdev->supported_events)) { | |
2166 | kfree(evt); | |
2167 | return; | |
2168 | } | |
2169 | ||
2170 | spin_lock_irqsave(&sdev->list_lock, flags); | |
2171 | list_add_tail(&evt->node, &sdev->event_list); | |
2172 | schedule_work(&sdev->event_work); | |
2173 | spin_unlock_irqrestore(&sdev->list_lock, flags); | |
2174 | } | |
2175 | EXPORT_SYMBOL_GPL(sdev_evt_send); | |
2176 | ||
2177 | /** | |
2178 | * sdev_evt_alloc - allocate a new scsi event | |
2179 | * @evt_type: type of event to allocate | |
2180 | * @gfpflags: GFP flags for allocation | |
2181 | * | |
2182 | * Allocates and returns a new scsi_event. | |
2183 | */ | |
2184 | struct scsi_event *sdev_evt_alloc(enum scsi_device_event evt_type, | |
2185 | gfp_t gfpflags) | |
2186 | { | |
2187 | struct scsi_event *evt = kzalloc(sizeof(struct scsi_event), gfpflags); | |
2188 | if (!evt) | |
2189 | return NULL; | |
2190 | ||
2191 | evt->evt_type = evt_type; | |
2192 | INIT_LIST_HEAD(&evt->node); | |
2193 | ||
2194 | /* evt_type-specific initialization, if any */ | |
2195 | switch (evt_type) { | |
2196 | case SDEV_EVT_MEDIA_CHANGE: | |
2197 | default: | |
2198 | /* do nothing */ | |
2199 | break; | |
2200 | } | |
2201 | ||
2202 | return evt; | |
2203 | } | |
2204 | EXPORT_SYMBOL_GPL(sdev_evt_alloc); | |
2205 | ||
2206 | /** | |
2207 | * sdev_evt_send_simple - send asserted event to uevent thread | |
2208 | * @sdev: scsi_device event occurred on | |
2209 | * @evt_type: type of event to send | |
2210 | * @gfpflags: GFP flags for allocation | |
2211 | * | |
2212 | * Assert scsi device event asynchronously, given an event type. | |
2213 | */ | |
2214 | void sdev_evt_send_simple(struct scsi_device *sdev, | |
2215 | enum scsi_device_event evt_type, gfp_t gfpflags) | |
2216 | { | |
2217 | struct scsi_event *evt = sdev_evt_alloc(evt_type, gfpflags); | |
2218 | if (!evt) { | |
2219 | sdev_printk(KERN_ERR, sdev, "event %d eaten due to OOM\n", | |
2220 | evt_type); | |
2221 | return; | |
2222 | } | |
2223 | ||
2224 | sdev_evt_send(sdev, evt); | |
2225 | } | |
2226 | EXPORT_SYMBOL_GPL(sdev_evt_send_simple); | |
2227 | ||
1da177e4 LT |
2228 | /** |
2229 | * scsi_device_quiesce - Block user issued commands. | |
2230 | * @sdev: scsi device to quiesce. | |
2231 | * | |
2232 | * This works by trying to transition to the SDEV_QUIESCE state | |
2233 | * (which must be a legal transition). When the device is in this | |
2234 | * state, only special requests will be accepted, all others will | |
2235 | * be deferred. Since special requests may also be requeued requests, | |
2236 | * a successful return doesn't guarantee the device will be | |
2237 | * totally quiescent. | |
2238 | * | |
2239 | * Must be called with user context, may sleep. | |
2240 | * | |
2241 | * Returns zero if unsuccessful or an error if not. | |
eb44820c | 2242 | */ |
1da177e4 LT |
2243 | int |
2244 | scsi_device_quiesce(struct scsi_device *sdev) | |
2245 | { | |
2246 | int err = scsi_device_set_state(sdev, SDEV_QUIESCE); | |
2247 | if (err) | |
2248 | return err; | |
2249 | ||
2250 | scsi_run_queue(sdev->request_queue); | |
2251 | while (sdev->device_busy) { | |
2252 | msleep_interruptible(200); | |
2253 | scsi_run_queue(sdev->request_queue); | |
2254 | } | |
2255 | return 0; | |
2256 | } | |
2257 | EXPORT_SYMBOL(scsi_device_quiesce); | |
2258 | ||
2259 | /** | |
2260 | * scsi_device_resume - Restart user issued commands to a quiesced device. | |
2261 | * @sdev: scsi device to resume. | |
2262 | * | |
2263 | * Moves the device from quiesced back to running and restarts the | |
2264 | * queues. | |
2265 | * | |
2266 | * Must be called with user context, may sleep. | |
eb44820c | 2267 | */ |
1da177e4 LT |
2268 | void |
2269 | scsi_device_resume(struct scsi_device *sdev) | |
2270 | { | |
2271 | if(scsi_device_set_state(sdev, SDEV_RUNNING)) | |
2272 | return; | |
2273 | scsi_run_queue(sdev->request_queue); | |
2274 | } | |
2275 | EXPORT_SYMBOL(scsi_device_resume); | |
2276 | ||
2277 | static void | |
2278 | device_quiesce_fn(struct scsi_device *sdev, void *data) | |
2279 | { | |
2280 | scsi_device_quiesce(sdev); | |
2281 | } | |
2282 | ||
2283 | void | |
2284 | scsi_target_quiesce(struct scsi_target *starget) | |
2285 | { | |
2286 | starget_for_each_device(starget, NULL, device_quiesce_fn); | |
2287 | } | |
2288 | EXPORT_SYMBOL(scsi_target_quiesce); | |
2289 | ||
2290 | static void | |
2291 | device_resume_fn(struct scsi_device *sdev, void *data) | |
2292 | { | |
2293 | scsi_device_resume(sdev); | |
2294 | } | |
2295 | ||
2296 | void | |
2297 | scsi_target_resume(struct scsi_target *starget) | |
2298 | { | |
2299 | starget_for_each_device(starget, NULL, device_resume_fn); | |
2300 | } | |
2301 | EXPORT_SYMBOL(scsi_target_resume); | |
2302 | ||
2303 | /** | |
eb44820c | 2304 | * scsi_internal_device_block - internal function to put a device temporarily into the SDEV_BLOCK state |
1da177e4 LT |
2305 | * @sdev: device to block |
2306 | * | |
2307 | * Block request made by scsi lld's to temporarily stop all | |
2308 | * scsi commands on the specified device. Called from interrupt | |
2309 | * or normal process context. | |
2310 | * | |
2311 | * Returns zero if successful or error if not | |
2312 | * | |
2313 | * Notes: | |
2314 | * This routine transitions the device to the SDEV_BLOCK state | |
2315 | * (which must be a legal transition). When the device is in this | |
2316 | * state, all commands are deferred until the scsi lld reenables | |
2317 | * the device with scsi_device_unblock or device_block_tmo fires. | |
2318 | * This routine assumes the host_lock is held on entry. | |
eb44820c | 2319 | */ |
1da177e4 LT |
2320 | int |
2321 | scsi_internal_device_block(struct scsi_device *sdev) | |
2322 | { | |
165125e1 | 2323 | struct request_queue *q = sdev->request_queue; |
1da177e4 LT |
2324 | unsigned long flags; |
2325 | int err = 0; | |
2326 | ||
2327 | err = scsi_device_set_state(sdev, SDEV_BLOCK); | |
2328 | if (err) | |
2329 | return err; | |
2330 | ||
2331 | /* | |
2332 | * The device has transitioned to SDEV_BLOCK. Stop the | |
2333 | * block layer from calling the midlayer with this device's | |
2334 | * request queue. | |
2335 | */ | |
2336 | spin_lock_irqsave(q->queue_lock, flags); | |
2337 | blk_stop_queue(q); | |
2338 | spin_unlock_irqrestore(q->queue_lock, flags); | |
2339 | ||
2340 | return 0; | |
2341 | } | |
2342 | EXPORT_SYMBOL_GPL(scsi_internal_device_block); | |
2343 | ||
2344 | /** | |
2345 | * scsi_internal_device_unblock - resume a device after a block request | |
2346 | * @sdev: device to resume | |
2347 | * | |
2348 | * Called by scsi lld's or the midlayer to restart the device queue | |
2349 | * for the previously suspended scsi device. Called from interrupt or | |
2350 | * normal process context. | |
2351 | * | |
2352 | * Returns zero if successful or error if not. | |
2353 | * | |
2354 | * Notes: | |
2355 | * This routine transitions the device to the SDEV_RUNNING state | |
2356 | * (which must be a legal transition) allowing the midlayer to | |
2357 | * goose the queue for this device. This routine assumes the | |
2358 | * host_lock is held upon entry. | |
eb44820c | 2359 | */ |
1da177e4 LT |
2360 | int |
2361 | scsi_internal_device_unblock(struct scsi_device *sdev) | |
2362 | { | |
165125e1 | 2363 | struct request_queue *q = sdev->request_queue; |
1da177e4 LT |
2364 | int err; |
2365 | unsigned long flags; | |
2366 | ||
2367 | /* | |
2368 | * Try to transition the scsi device to SDEV_RUNNING | |
2369 | * and goose the device queue if successful. | |
2370 | */ | |
2371 | err = scsi_device_set_state(sdev, SDEV_RUNNING); | |
2372 | if (err) | |
2373 | return err; | |
2374 | ||
2375 | spin_lock_irqsave(q->queue_lock, flags); | |
2376 | blk_start_queue(q); | |
2377 | spin_unlock_irqrestore(q->queue_lock, flags); | |
2378 | ||
2379 | return 0; | |
2380 | } | |
2381 | EXPORT_SYMBOL_GPL(scsi_internal_device_unblock); | |
2382 | ||
2383 | static void | |
2384 | device_block(struct scsi_device *sdev, void *data) | |
2385 | { | |
2386 | scsi_internal_device_block(sdev); | |
2387 | } | |
2388 | ||
2389 | static int | |
2390 | target_block(struct device *dev, void *data) | |
2391 | { | |
2392 | if (scsi_is_target_device(dev)) | |
2393 | starget_for_each_device(to_scsi_target(dev), NULL, | |
2394 | device_block); | |
2395 | return 0; | |
2396 | } | |
2397 | ||
2398 | void | |
2399 | scsi_target_block(struct device *dev) | |
2400 | { | |
2401 | if (scsi_is_target_device(dev)) | |
2402 | starget_for_each_device(to_scsi_target(dev), NULL, | |
2403 | device_block); | |
2404 | else | |
2405 | device_for_each_child(dev, NULL, target_block); | |
2406 | } | |
2407 | EXPORT_SYMBOL_GPL(scsi_target_block); | |
2408 | ||
2409 | static void | |
2410 | device_unblock(struct scsi_device *sdev, void *data) | |
2411 | { | |
2412 | scsi_internal_device_unblock(sdev); | |
2413 | } | |
2414 | ||
2415 | static int | |
2416 | target_unblock(struct device *dev, void *data) | |
2417 | { | |
2418 | if (scsi_is_target_device(dev)) | |
2419 | starget_for_each_device(to_scsi_target(dev), NULL, | |
2420 | device_unblock); | |
2421 | return 0; | |
2422 | } | |
2423 | ||
2424 | void | |
2425 | scsi_target_unblock(struct device *dev) | |
2426 | { | |
2427 | if (scsi_is_target_device(dev)) | |
2428 | starget_for_each_device(to_scsi_target(dev), NULL, | |
2429 | device_unblock); | |
2430 | else | |
2431 | device_for_each_child(dev, NULL, target_unblock); | |
2432 | } | |
2433 | EXPORT_SYMBOL_GPL(scsi_target_unblock); | |
cdb8c2a6 GL |
2434 | |
2435 | /** | |
2436 | * scsi_kmap_atomic_sg - find and atomically map an sg-elemnt | |
eb44820c | 2437 | * @sgl: scatter-gather list |
cdb8c2a6 GL |
2438 | * @sg_count: number of segments in sg |
2439 | * @offset: offset in bytes into sg, on return offset into the mapped area | |
2440 | * @len: bytes to map, on return number of bytes mapped | |
2441 | * | |
2442 | * Returns virtual address of the start of the mapped page | |
2443 | */ | |
c6132da1 | 2444 | void *scsi_kmap_atomic_sg(struct scatterlist *sgl, int sg_count, |
cdb8c2a6 GL |
2445 | size_t *offset, size_t *len) |
2446 | { | |
2447 | int i; | |
2448 | size_t sg_len = 0, len_complete = 0; | |
c6132da1 | 2449 | struct scatterlist *sg; |
cdb8c2a6 GL |
2450 | struct page *page; |
2451 | ||
22cfefb5 AM |
2452 | WARN_ON(!irqs_disabled()); |
2453 | ||
c6132da1 | 2454 | for_each_sg(sgl, sg, sg_count, i) { |
cdb8c2a6 | 2455 | len_complete = sg_len; /* Complete sg-entries */ |
c6132da1 | 2456 | sg_len += sg->length; |
cdb8c2a6 GL |
2457 | if (sg_len > *offset) |
2458 | break; | |
2459 | } | |
2460 | ||
2461 | if (unlikely(i == sg_count)) { | |
169e1a2a AM |
2462 | printk(KERN_ERR "%s: Bytes in sg: %zu, requested offset %zu, " |
2463 | "elements %d\n", | |
cdb8c2a6 GL |
2464 | __FUNCTION__, sg_len, *offset, sg_count); |
2465 | WARN_ON(1); | |
2466 | return NULL; | |
2467 | } | |
2468 | ||
2469 | /* Offset starting from the beginning of first page in this sg-entry */ | |
c6132da1 | 2470 | *offset = *offset - len_complete + sg->offset; |
cdb8c2a6 GL |
2471 | |
2472 | /* Assumption: contiguous pages can be accessed as "page + i" */ | |
45711f1a | 2473 | page = nth_page(sg_page(sg), (*offset >> PAGE_SHIFT)); |
cdb8c2a6 GL |
2474 | *offset &= ~PAGE_MASK; |
2475 | ||
2476 | /* Bytes in this sg-entry from *offset to the end of the page */ | |
2477 | sg_len = PAGE_SIZE - *offset; | |
2478 | if (*len > sg_len) | |
2479 | *len = sg_len; | |
2480 | ||
2481 | return kmap_atomic(page, KM_BIO_SRC_IRQ); | |
2482 | } | |
2483 | EXPORT_SYMBOL(scsi_kmap_atomic_sg); | |
2484 | ||
2485 | /** | |
eb44820c | 2486 | * scsi_kunmap_atomic_sg - atomically unmap a virtual address, previously mapped with scsi_kmap_atomic_sg |
cdb8c2a6 GL |
2487 | * @virt: virtual address to be unmapped |
2488 | */ | |
2489 | void scsi_kunmap_atomic_sg(void *virt) | |
2490 | { | |
2491 | kunmap_atomic(virt, KM_BIO_SRC_IRQ); | |
2492 | } | |
2493 | EXPORT_SYMBOL(scsi_kunmap_atomic_sg); |