blob: b12fb310e3999af497c21778b62f40c46892e8fd [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
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>
James Bottomleyd3f46f32008-01-15 11:11:46 -060011#include <linux/bitops.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070012#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>
James Bottomleyfaead262006-02-14 10:42:07 -060020#include <linux/hardirq.h>
Jens Axboec6132da2007-10-16 11:08:49 +020021#include <linux/scatterlist.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070022
23#include <scsi/scsi.h>
Christoph Hellwigbeb40482006-06-10 18:01:03 +020024#include <scsi/scsi_cmnd.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070025#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>
Linus Torvalds1da177e2005-04-16 15:20:36 -070030
31#include "scsi_priv.h"
32#include "scsi_logging.h"
33
34
Tobias Klauser6391a112006-06-08 22:23:48 -070035#define SG_MEMPOOL_NR ARRAY_SIZE(scsi_sg_pools)
Jens Axboe59725112007-04-02 10:06:42 +020036#define SG_MEMPOOL_SIZE 2
Linus Torvalds1da177e2005-04-16 15:20:36 -070037
38struct scsi_host_sg_pool {
39 size_t size;
Jens Axboea8474ce2007-08-07 09:02:51 +020040 char *name;
Christoph Lametere18b8902006-12-06 20:33:20 -080041 struct kmem_cache *slab;
Linus Torvalds1da177e2005-04-16 15:20:36 -070042 mempool_t *pool;
43};
44
James Bottomleyd3f46f32008-01-15 11:11:46 -060045#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
Adrian Bunk52c1da32005-06-23 22:05:33 -070049static struct scsi_host_sg_pool scsi_sg_pools[] = {
Linus Torvalds1da177e2005-04-16 15:20:36 -070050 SP(8),
51 SP(16),
FUJITA Tomonorifd820f42007-09-18 12:14:37 +020052#if (SCSI_MAX_SG_SEGMENTS > 32)
James Bottomleyd3f46f32008-01-15 11:11:46 -060053 SP(32),
FUJITA Tomonorifd820f42007-09-18 12:14:37 +020054#if (SCSI_MAX_SG_SEGMENTS > 64)
James Bottomleyd3f46f32008-01-15 11:11:46 -060055 SP(64),
56#if (SCSI_MAX_SG_SEGMENTS > 128)
Linus Torvalds1da177e2005-04-16 15:20:36 -070057 SP(128),
James Bottomleyd3f46f32008-01-15 11:11:46 -060058#if (SCSI_MAX_SG_SEGMENTS > 256)
59#error SCSI_MAX_SG_SEGMENTS is too large (256 MAX)
FUJITA Tomonorifd820f42007-09-18 12:14:37 +020060#endif
61#endif
62#endif
James Bottomleyd3f46f32008-01-15 11:11:46 -060063#endif
64 SP(SCSI_MAX_SG_SEGMENTS)
Jens Axboea8474ce2007-08-07 09:02:51 +020065};
Linus Torvalds1da177e2005-04-16 15:20:36 -070066#undef SP
67
Boaz Harrosh6f9a35e2007-12-13 13:50:53 +020068static struct kmem_cache *scsi_bidi_sdb_cache;
69
Tejun Heo a1bf9d12005-04-24 02:08:52 -050070static void scsi_run_queue(struct request_queue *q);
James Bottomleye91442b2005-09-09 10:44:16 -050071
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 */
84static void scsi_unprep_request(struct request *req)
85{
86 struct scsi_cmnd *cmd = req->special;
87
Jens Axboe4aff5e22006-08-10 08:44:47 +020088 req->cmd_flags &= ~REQ_DONTPREP;
Christoph Hellwigbeb40482006-06-10 18:01:03 +020089 req->special = NULL;
James Bottomleye91442b2005-09-09 10:44:16 -050090
James Bottomleye91442b2005-09-09 10:44:16 -050091 scsi_put_command(cmd);
92}
Tejun Heo a1bf9d12005-04-24 02:08:52 -050093
Linus Torvalds1da177e2005-04-16 15:20:36 -070094/*
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 */
113int 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;
Tejun Heo a1bf9d12005-04-24 02:08:52 -0500117 struct request_queue *q = device->request_queue;
118 unsigned long flags;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700119
120 SCSI_LOG_MLQUEUE(1,
121 printk("Inserting command %p into mlqueue\n", cmd));
122
123 /*
Tejun Heo d8c37e72005-05-14 00:46:08 +0900124 * Set the appropriate busy bit for the device/host.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700125 *
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
141 /*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700142 * Decrement the counters, since these commands are no longer
143 * active on the host/device.
144 */
145 scsi_device_unbusy(device);
146
147 /*
Tejun Heo a1bf9d12005-04-24 02:08:52 -0500148 * Requeue this command. It will go before all other commands
149 * that are already in the queue.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700150 *
151 * NOTE: there is magic here about the way the queue is plugged if
152 * we have no outstanding commands.
153 *
Tejun Heo a1bf9d12005-04-24 02:08:52 -0500154 * Although we *don't* plug the queue, we call the request
Linus Torvalds1da177e2005-04-16 15:20:36 -0700155 * function. The SCSI request function detects the blocked condition
156 * and plugs the queue appropriately.
Tejun Heo a1bf9d12005-04-24 02:08:52 -0500157 */
158 spin_lock_irqsave(q->queue_lock, flags);
James Bottomley59897da2005-09-14 12:57:42 -0400159 blk_requeue_request(q, cmd->request);
Tejun Heo a1bf9d12005-04-24 02:08:52 -0500160 spin_unlock_irqrestore(q->queue_lock, flags);
161
162 scsi_run_queue(q);
163
Linus Torvalds1da177e2005-04-16 15:20:36 -0700164 return 0;
165}
166
James Bottomley39216032005-06-15 18:48:29 -0500167/**
James Bottomley33aa6872005-08-28 11:31:14 -0500168 * scsi_execute - insert request and wait for the result
James Bottomley39216032005-06-15 18:48:29 -0500169 * @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
James Bottomley33aa6872005-08-28 11:31:14 -0500177 * @flags: or into request flags;
James Bottomley39216032005-06-15 18:48:29 -0500178 *
Michael Opdenacker59c51592007-05-09 08:57:56 +0200179 * returns the req->errors value which is the scsi_cmnd result
James Bottomleyea73a9f2005-08-28 11:33:52 -0500180 * field.
Rob Landleyeb448202007-11-03 13:30:39 -0500181 */
James Bottomley33aa6872005-08-28 11:31:14 -0500182int 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)
James Bottomley39216032005-06-15 18:48:29 -0500185{
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;
Mike Christie17e01f22005-11-11 05:31:37 -0600200 req->retries = retries;
James Bottomley39216032005-06-15 18:48:29 -0500201 req->timeout = timeout;
Jens Axboe4aff5e22006-08-10 08:44:47 +0200202 req->cmd_type = REQ_TYPE_BLOCK_PC;
203 req->cmd_flags |= flags | REQ_QUIET | REQ_PREEMPT;
James Bottomley39216032005-06-15 18:48:29 -0500204
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}
James Bottomley33aa6872005-08-28 11:31:14 -0500216EXPORT_SYMBOL(scsi_execute);
James Bottomley39216032005-06-15 18:48:29 -0500217
James Bottomleyea73a9f2005-08-28 11:33:52 -0500218
219int 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;
akpm@osdl.org1ccb48b2005-06-26 00:12:51 -0700224 int result;
225
James Bottomleyea73a9f2005-08-28 11:33:52 -0500226 if (sshdr) {
Jes Sorensen24669f752006-01-16 10:31:18 -0500227 sense = kzalloc(SCSI_SENSE_BUFFERSIZE, GFP_NOIO);
James Bottomleyea73a9f2005-08-28 11:33:52 -0500228 if (!sense)
229 return DRIVER_ERROR << 24;
James Bottomleyea73a9f2005-08-28 11:33:52 -0500230 }
akpm@osdl.org1ccb48b2005-06-26 00:12:51 -0700231 result = scsi_execute(sdev, cmd, data_direction, buffer, bufflen,
Jes Sorensen24669f752006-01-16 10:31:18 -0500232 sense, timeout, retries, 0);
James Bottomleyea73a9f2005-08-28 11:33:52 -0500233 if (sshdr)
James Bottomleye5143852005-08-09 11:55:36 -0500234 scsi_normalize_sense(sense, SCSI_SENSE_BUFFERSIZE, sshdr);
James Bottomleyea73a9f2005-08-28 11:33:52 -0500235
236 kfree(sense);
237 return result;
238}
239EXPORT_SYMBOL(scsi_execute_req);
240
Mike Christie6e68af62005-11-11 05:30:27 -0600241struct 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
Christoph Lametere18b8902006-12-06 20:33:20 -0800247static struct kmem_cache *scsi_io_context_cache;
Mike Christieaa7b5cd2005-11-11 05:31:41 -0600248
Jens Axboee650c302006-01-06 12:38:30 +0100249static void scsi_end_async(struct request *req, int uptodate)
Mike Christie6e68af62005-11-11 05:30:27 -0600250{
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
Mike Christieaa7b5cd2005-11-11 05:31:41 -0600256 kmem_cache_free(scsi_io_context_cache, sioc);
Mike Christie6e68af62005-11-11 05:30:27 -0600257 __blk_put_request(req->q, req);
258}
259
260static 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
NeilBrown3001ca72007-08-16 13:31:27 +0200269 return blk_rq_append_bio(q, rq, bio);
Mike Christie6e68af62005-11-11 05:30:27 -0600270}
271
NeilBrown6712ecf2007-09-27 12:47:43 +0200272static void scsi_bi_endio(struct bio *bio, int error)
Mike Christie6e68af62005-11-11 05:30:27 -0600273{
Mike Christie6e68af62005-11-11 05:30:27 -0600274 bio_put(bio);
Mike Christie6e68af62005-11-11 05:30:27 -0600275}
276
277/**
278 * scsi_req_map_sg - map a scatterlist into a request
279 * @rq: request to fill
Rob Landleyeb448202007-11-03 13:30:39 -0500280 * @sgl: scatterlist
Mike Christie6e68af62005-11-11 05:30:27 -0600281 * @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 */
289static 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;
Bryan Holtyf5235962006-03-22 06:35:39 -0600293 int nr_pages = (bufflen + sgl[0].offset + PAGE_SIZE - 1) >> PAGE_SHIFT;
Mike Christiebd441de2007-03-13 12:52:29 -0500294 unsigned int data_len = bufflen, len, bytes, off;
Jens Axboec6132da2007-10-16 11:08:49 +0200295 struct scatterlist *sg;
Mike Christie6e68af62005-11-11 05:30:27 -0600296 struct page *page;
297 struct bio *bio = NULL;
298 int i, err, nr_vecs = 0;
299
Jens Axboec6132da2007-10-16 11:08:49 +0200300 for_each_sg(sgl, sg, nsegs, i) {
Jens Axboe45711f12007-10-22 21:19:53 +0200301 page = sg_page(sg);
Jens Axboec6132da2007-10-16 11:08:49 +0200302 off = sg->offset;
303 len = sg->length;
304 data_len += len;
Mike Christie6e68af62005-11-11 05:30:27 -0600305
Mike Christiebd441de2007-03-13 12:52:29 -0500306 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 */
Mike Christie6e68af62005-11-11 05:30:27 -0600312 bytes = min_t(unsigned int, len, PAGE_SIZE - off);
Mike Christiebd441de2007-03-13 12:52:29 -0500313 bytes = min(bytes, data_len);
Mike Christie6e68af62005-11-11 05:30:27 -0600314
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) {
NeilBrown6712ecf2007-09-27 12:47:43 +0200337 bio_endio(bio, 0);
Mike Christie6e68af62005-11-11 05:30:27 -0600338 goto free_bios;
339 }
340 bio = NULL;
341 }
342
343 page++;
344 len -= bytes;
Mike Christiebd441de2007-03-13 12:52:29 -0500345 data_len -=bytes;
Mike Christie6e68af62005-11-11 05:30:27 -0600346 off = 0;
347 }
348 }
349
350 rq->buffer = rq->data = NULL;
Mike Christiebd441de2007-03-13 12:52:29 -0500351 rq->data_len = bufflen;
Mike Christie6e68af62005-11-11 05:30:27 -0600352 return 0;
353
354free_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 */
NeilBrown6712ecf2007-09-27 12:47:43 +0200360 bio_endio(bio, 0);
Mike Christie6e68af62005-11-11 05:30:27 -0600361 }
362
363 return err;
364}
365
366/**
367 * scsi_execute_async - insert request
368 * @sdev: scsi device
369 * @cmd: scsi command
brking@us.ibm.combb1d1072006-01-23 15:03:22 -0600370 * @cmd_len: length of scsi cdb
Rob Landleyeb448202007-11-03 13:30:39 -0500371 * @data_direction: DMA_TO_DEVICE, DMA_FROM_DEVICE, or DMA_NONE
Mike Christie6e68af62005-11-11 05:30:27 -0600372 * @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
Rob Landleyeb448202007-11-03 13:30:39 -0500377 * @privdata: data passed to done()
378 * @done: callback function when done
379 * @gfp: memory allocation flags
380 */
Mike Christie6e68af62005-11-11 05:30:27 -0600381int scsi_execute_async(struct scsi_device *sdev, const unsigned char *cmd,
brking@us.ibm.combb1d1072006-01-23 15:03:22 -0600382 int cmd_len, int data_direction, void *buffer, unsigned bufflen,
Mike Christie6e68af62005-11-11 05:30:27 -0600383 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
Robert P. J. Dayc3762222007-02-10 01:45:03 -0800391 sioc = kmem_cache_zalloc(scsi_io_context_cache, gfp);
Mike Christie6e68af62005-11-11 05:30:27 -0600392 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;
Jens Axboe4aff5e22006-08-10 08:44:47 +0200398 req->cmd_type = REQ_TYPE_BLOCK_PC;
399 req->cmd_flags |= REQ_QUIET;
Mike Christie6e68af62005-11-11 05:30:27 -0600400
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
brking@us.ibm.combb1d1072006-01-23 15:03:22 -0600409 req->cmd_len = cmd_len;
Tejun Heo097b8452006-11-16 01:19:31 -0800410 memset(req->cmd, 0, BLK_MAX_CDB); /* ATAPI hates garbage after CDB */
Mike Christie6e68af62005-11-11 05:30:27 -0600411 memcpy(req->cmd, cmd, req->cmd_len);
412 req->sense = sioc->sense;
413 req->sense_len = 0;
414 req->timeout = timeout;
Mike Christie17e01f22005-11-11 05:31:37 -0600415 req->retries = retries;
Mike Christie6e68af62005-11-11 05:30:27 -0600416 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
424free_req:
425 blk_put_request(req);
426free_sense:
Arne Redlich6470f2b2006-09-30 15:49:40 +0200427 kmem_cache_free(scsi_io_context_cache, sioc);
Mike Christie6e68af62005-11-11 05:30:27 -0600428 return DRIVER_ERROR << 24;
429}
430EXPORT_SYMBOL_GPL(scsi_execute_async);
431
Linus Torvalds1da177e2005-04-16 15:20:36 -0700432/*
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 *
Linus Torvalds1da177e2005-04-16 15:20:36 -0700439 * 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 */
Christoph Hellwig631c2282006-07-08 20:42:15 +0200443static void scsi_init_cmd_errh(struct scsi_cmnd *cmd)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700444{
Linus Torvalds1da177e2005-04-16 15:20:36 -0700445 cmd->serial_number = 0;
Boaz Harrosh30b0c372007-12-13 13:47:40 +0200446 scsi_set_resid(cmd, 0);
FUJITA Tomonorib80ca4f2008-01-13 15:46:13 +0900447 memset(cmd->sense_buffer, 0, SCSI_SENSE_BUFFERSIZE);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700448 if (cmd->cmd_len == 0)
449 cmd->cmd_len = COMMAND_SIZE(cmd->cmnd[0]);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700450}
451
452void 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--;
James Bottomley939647e2005-09-18 15:05:20 -0500459 if (unlikely(scsi_host_in_recovery(shost) &&
Tejun Heoee7863b2006-05-15 20:57:20 +0900460 (shost->host_failed || shost->host_eh_scheduled)))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700461 scsi_eh_wakeup(shost);
462 spin_unlock(shost->host_lock);
152587d2005-04-12 16:22:06 -0500463 spin_lock(sdev->request_queue->queue_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700464 sdev->device_busy--;
152587d2005-04-12 16:22:06 -0500465 spin_unlock_irqrestore(sdev->request_queue->queue_lock, flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700466}
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 */
475static 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 */
526static 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
Tony Battersby25d7c362007-11-12 10:00:44 -0500532 if (scsi_target(sdev)->single_lun)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700533 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
Andreas Herrmann04846f22006-08-09 17:31:16 +0200555
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);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700564
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.
James Bottomleye91442b2005-09-09 10:44:16 -0500595 * Notes: Upon return, cmd is a stale pointer.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700596 */
597static void scsi_requeue_command(struct request_queue *q, struct scsi_cmnd *cmd)
598{
James Bottomleye91442b2005-09-09 10:44:16 -0500599 struct request *req = cmd->request;
Tejun Heo 283369c2005-04-24 02:06:36 -0500600 unsigned long flags;
601
James Bottomleye91442b2005-09-09 10:44:16 -0500602 scsi_unprep_request(req);
Tejun Heo 283369c2005-04-24 02:06:36 -0500603 spin_lock_irqsave(q->queue_lock, flags);
James Bottomleye91442b2005-09-09 10:44:16 -0500604 blk_requeue_request(q, req);
Tejun Heo 283369c2005-04-24 02:06:36 -0500605 spin_unlock_irqrestore(q->queue_lock, flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700606
607 scsi_run_queue(q);
608}
609
610void scsi_next_command(struct scsi_cmnd *cmd)
611{
Linus Torvalds49d7bc62005-12-12 11:25:04 -0800612 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);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700617
618 scsi_put_command(cmd);
619 scsi_run_queue(q);
Linus Torvalds49d7bc62005-12-12 11:25:04 -0800620
621 /* ok to remove device now */
622 put_device(&sdev->sdev_gendev);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700623}
624
625void 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.
Kiyoshi Ueda610d8b02007-12-11 17:52:09 -0500640 * error - 0 if I/O indicates success, < 0 for I/O error.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700641 * 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 *
James Bottomleye91442b2005-09-09 10:44:16 -0500646 * Returns: cmd if requeue required, NULL otherwise.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700647 *
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.
James Bottomleye91442b2005-09-09 10:44:16 -0500653 * Notes: If cmd was requeued, upon return it will be a stale pointer.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700654 */
Kiyoshi Ueda610d8b02007-12-11 17:52:09 -0500655static struct scsi_cmnd *scsi_end_request(struct scsi_cmnd *cmd, int error,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700656 int bytes, int requeue)
657{
Jens Axboe165125e2007-07-24 09:28:11 +0200658 struct request_queue *q = cmd->device->request_queue;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700659 struct request *req = cmd->request;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700660
661 /*
662 * If there are blocks left over at the end, set up the command
663 * to queue the remainder of them.
664 */
Kiyoshi Ueda610d8b02007-12-11 17:52:09 -0500665 if (blk_end_request(req, error, bytes)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700666 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 */
Kiyoshi Ueda610d8b02007-12-11 17:52:09 -0500672 if (error && blk_noretry_request(req))
673 blk_end_request(req, error, leftover);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700674 else {
James Bottomleye91442b2005-09-09 10:44:16 -0500675 if (requeue) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700676 /*
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);
James Bottomleye91442b2005-09-09 10:44:16 -0500682 cmd = NULL;
683 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700684 return cmd;
685 }
686 }
687
Linus Torvalds1da177e2005-04-16 15:20:36 -0700688 /*
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
Jens Axboea8474ce2007-08-07 09:02:51 +0200696static inline unsigned int scsi_sgtable_index(unsigned short nents)
697{
698 unsigned int index;
699
James Bottomleyd3f46f32008-01-15 11:11:46 -0600700 BUG_ON(nents > SCSI_MAX_SG_SEGMENTS);
701
702 if (nents <= 8)
Jens Axboea8474ce2007-08-07 09:02:51 +0200703 index = 0;
James Bottomleyd3f46f32008-01-15 11:11:46 -0600704 else
705 index = get_count_order(nents) - 3;
Jens Axboea8474ce2007-08-07 09:02:51 +0200706
707 return index;
708}
709
Jens Axboe5ed79592007-11-15 09:13:11 +0100710static void scsi_sg_free(struct scatterlist *sgl, unsigned int nents)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700711{
712 struct scsi_host_sg_pool *sgp;
Jens Axboe5ed79592007-11-15 09:13:11 +0100713
714 sgp = scsi_sg_pools + scsi_sgtable_index(nents);
715 mempool_free(sgl, sgp->pool);
716}
717
718static struct scatterlist *scsi_sg_alloc(unsigned int nents, gfp_t gfp_mask)
719{
720 struct scsi_host_sg_pool *sgp;
721
722 sgp = scsi_sg_pools + scsi_sgtable_index(nents);
723 return mempool_alloc(sgp->pool, gfp_mask);
724}
725
Boaz Harrosh30b0c372007-12-13 13:47:40 +0200726static int scsi_alloc_sgtable(struct scsi_data_buffer *sdb, int nents,
727 gfp_t gfp_mask)
Jens Axboe5ed79592007-11-15 09:13:11 +0100728{
729 int ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700730
Boaz Harrosh30b0c372007-12-13 13:47:40 +0200731 BUG_ON(!nents);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700732
Boaz Harrosh30b0c372007-12-13 13:47:40 +0200733 ret = __sg_alloc_table(&sdb->table, nents, SCSI_MAX_SG_SEGMENTS,
734 gfp_mask, scsi_sg_alloc);
Jens Axboe5ed79592007-11-15 09:13:11 +0100735 if (unlikely(ret))
Boaz Harrosh30b0c372007-12-13 13:47:40 +0200736 __sg_free_table(&sdb->table, SCSI_MAX_SG_SEGMENTS,
James Bottomley7cedb1f2008-01-13 14:15:28 -0600737 scsi_sg_free);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700738
Jens Axboea8474ce2007-08-07 09:02:51 +0200739 return ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700740}
741
Boaz Harrosh30b0c372007-12-13 13:47:40 +0200742static void scsi_free_sgtable(struct scsi_data_buffer *sdb)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700743{
Boaz Harrosh30b0c372007-12-13 13:47:40 +0200744 __sg_free_table(&sdb->table, SCSI_MAX_SG_SEGMENTS, scsi_sg_free);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700745}
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 */
Boaz Harroshbb52d822007-12-13 16:14:27 -0800764void scsi_release_buffers(struct scsi_cmnd *cmd)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700765{
Boaz Harrosh30b0c372007-12-13 13:47:40 +0200766 if (cmd->sdb.table.nents)
767 scsi_free_sgtable(&cmd->sdb);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700768
Boaz Harrosh30b0c372007-12-13 13:47:40 +0200769 memset(&cmd->sdb, 0, sizeof(cmd->sdb));
Boaz Harrosh6f9a35e2007-12-13 13:50:53 +0200770
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 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700778}
Boaz Harroshbb52d822007-12-13 16:14:27 -0800779EXPORT_SYMBOL(scsi_release_buffers);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700780
781/*
Boaz Harrosh6f9a35e2007-12-13 13:50:53 +0200782 * 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 */
788void scsi_end_bidi_request(struct scsi_cmnd *cmd)
789{
Kiyoshi Uedab8de1632008-01-18 12:02:15 -0500790 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
Boaz Harrosh6f9a35e2007-12-13 13:50:53 +0200800 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
809/*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700810 * 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 */
Luben Tuikov03aba2f2006-06-23 09:39:09 -0700837void scsi_io_completion(struct scsi_cmnd *cmd, unsigned int good_bytes)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700838{
839 int result = cmd->result;
Boaz Harrosh30b0c372007-12-13 13:47:40 +0200840 int this_count = scsi_bufflen(cmd);
Jens Axboe165125e2007-07-24 09:28:11 +0200841 struct request_queue *q = cmd->device->request_queue;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700842 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
Linus Torvalds1da177e2005-04-16 15:20:36 -0700848 if (result) {
849 sense_valid = scsi_command_normalize_sense(cmd, &sshdr);
850 if (sense_valid)
851 sense_deferred = scsi_sense_is_deferred(&sshdr);
852 }
Christoph Hellwig631c2282006-07-08 20:42:15 +0200853
Linus Torvalds1da177e2005-04-16 15:20:36 -0700854 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 }
Pete Wyckoffb22f6872007-03-13 16:53:28 -0400869 }
Boaz Harrosh6f9a35e2007-12-13 13:50:53 +0200870 if (scsi_bidi_cmnd(cmd)) {
871 /* will also release_buffers */
872 scsi_end_bidi_request(cmd);
873 return;
874 }
Boaz Harrosh30b0c372007-12-13 13:47:40 +0200875 req->data_len = scsi_get_resid(cmd);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700876 }
877
Boaz Harrosh6f9a35e2007-12-13 13:50:53 +0200878 BUG_ON(blk_bidi_rq(req)); /* bidi not support for !blk_pc_request yet */
Boaz Harrosh30b0c372007-12-13 13:47:40 +0200879 scsi_release_buffers(cmd);
880
Linus Torvalds1da177e2005-04-16 15:20:36 -0700881 /*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700882 * Next deal with any sectors which we were able to correctly
883 * handle.
884 */
James Bottomleyd6b0c532006-07-02 10:06:28 -0500885 SCSI_LOG_HLCOMPLETE(1, printk("%ld sectors total, "
886 "%d bytes done.\n",
887 req->nr_sectors, good_bytes));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700888
James Bottomleyd6b0c532006-07-02 10:06:28 -0500889 if (clear_errors)
890 req->errors = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700891
James Bottomleyd6b0c532006-07-02 10:06:28 -0500892 /* 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 */
Kiyoshi Ueda610d8b02007-12-11 17:52:09 -0500896 if (scsi_end_request(cmd, 0, good_bytes, result == 0) == NULL)
James Bottomleyd6b0c532006-07-02 10:06:28 -0500897 return;
Luben Tuikov03aba2f2006-06-23 09:39:09 -0700898
899 /* good_bytes = 0, or (inclusive) there were leftovers and
900 * result = 0, so scsi_end_request couldn't retry.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700901 */
902 if (sense_valid && !sense_deferred) {
903 switch (sshdr.sense_key) {
904 case UNIT_ATTENTION:
905 if (cmd->device->removable) {
Luben Tuikov03aba2f2006-06-23 09:39:09 -0700906 /* Detected disc change. Set a bit
Linus Torvalds1da177e2005-04-16 15:20:36 -0700907 * and quietly refuse further access.
908 */
909 cmd->device->changed = 1;
Kiyoshi Ueda610d8b02007-12-11 17:52:09 -0500910 scsi_end_request(cmd, -EIO, this_count, 1);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700911 return;
912 } else {
Luben Tuikov03aba2f2006-06-23 09:39:09 -0700913 /* 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 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700918 scsi_requeue_command(q, cmd);
919 return;
920 }
921 break;
922 case ILLEGAL_REQUEST:
Luben Tuikov03aba2f2006-06-23 09:39:09 -0700923 /* 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 */
Jens Axboe26a68012005-11-29 21:03:34 +0100931 if ((cmd->device->use_10_for_rw &&
932 sshdr.asc == 0x20 && sshdr.ascq == 0x00) &&
Linus Torvalds1da177e2005-04-16 15:20:36 -0700933 (cmd->cmnd[0] == READ_10 ||
934 cmd->cmnd[0] == WRITE_10)) {
935 cmd->device->use_10_for_rw = 0;
Luben Tuikov03aba2f2006-06-23 09:39:09 -0700936 /* This will cause a retry with a
937 * 6-byte command.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700938 */
939 scsi_requeue_command(q, cmd);
Luben Tuikov03aba2f2006-06-23 09:39:09 -0700940 return;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700941 } else {
Kiyoshi Ueda610d8b02007-12-11 17:52:09 -0500942 scsi_end_request(cmd, -EIO, this_count, 1);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700943 return;
944 }
945 break;
946 case NOT_READY:
Luben Tuikov03aba2f2006-06-23 09:39:09 -0700947 /* If the device is in the process of becoming
James Bottomleyf3e93f72006-04-25 16:48:30 -0500948 * ready, or has a temporary blockage, retry.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700949 */
James Bottomleyf3e93f72006-04-25 16:48:30 -0500950 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 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700964 }
James Bottomley311b5812007-09-23 09:08:46 -0500965 if (!(req->cmd_flags & REQ_QUIET))
966 scsi_cmd_print_sense_hdr(cmd,
967 "Device not ready",
968 &sshdr);
969
Kiyoshi Ueda610d8b02007-12-11 17:52:09 -0500970 scsi_end_request(cmd, -EIO, this_count, 1);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700971 return;
972 case VOLUME_OVERFLOW:
Jens Axboe4aff5e22006-08-10 08:44:47 +0200973 if (!(req->cmd_flags & REQ_QUIET)) {
Jeff Garzik3bf743e2005-10-24 18:04:06 -0400974 scmd_printk(KERN_INFO, cmd,
Luben Tuikov03aba2f2006-06-23 09:39:09 -0700975 "Volume overflow, CDB: ");
Christoph Hellwig631c2282006-07-08 20:42:15 +0200976 __scsi_print_command(cmd->cmnd);
James Bottomley3173d8c2005-09-04 11:32:05 -0500977 scsi_print_sense("", cmd);
978 }
Luben Tuikov03aba2f2006-06-23 09:39:09 -0700979 /* See SSC3rXX or current. */
Kiyoshi Ueda610d8b02007-12-11 17:52:09 -0500980 scsi_end_request(cmd, -EIO, this_count, 1);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700981 return;
982 default:
983 break;
984 }
Luben Tuikov03aba2f2006-06-23 09:39:09 -0700985 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700986 if (host_byte(result) == DID_RESET) {
Luben Tuikov03aba2f2006-06-23 09:39:09 -0700987 /* Third party bus reset or reset for error recovery
988 * reasons. Just retry the request and see what
989 * happens.
Linus Torvalds1da177e2005-04-16 15:20:36 -0700990 */
991 scsi_requeue_command(q, cmd);
992 return;
993 }
994 if (result) {
Jens Axboe4aff5e22006-08-10 08:44:47 +0200995 if (!(req->cmd_flags & REQ_QUIET)) {
Martin K. Petersena4d04a42007-02-27 22:40:27 -0500996 scsi_print_result(cmd);
James Bottomley3173d8c2005-09-04 11:32:05 -0500997 if (driver_byte(result) & DRIVER_SENSE)
998 scsi_print_sense("", cmd);
999 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001000 }
Kiyoshi Ueda610d8b02007-12-11 17:52:09 -05001001 scsi_end_request(cmd, -EIO, this_count, !result);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001002}
Linus Torvalds1da177e2005-04-16 15:20:36 -07001003
Boaz Harrosh6f9a35e2007-12-13 13:50:53 +02001004static int scsi_init_sgtable(struct request *req, struct scsi_data_buffer *sdb,
1005 gfp_t gfp_mask)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001006{
Boaz Harrosh6f9a35e2007-12-13 13:50:53 +02001007 int count;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001008
1009 /*
Christoph Hellwig3b003152006-11-04 20:10:55 +01001010 * If sg table allocation fails, requeue request later.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001011 */
Boaz Harrosh30b0c372007-12-13 13:47:40 +02001012 if (unlikely(scsi_alloc_sgtable(sdb, req->nr_phys_segments,
1013 gfp_mask))) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001014 return BLKPREP_DEFER;
Alan Stern7c72ce82005-10-14 11:23:27 -04001015 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001016
Christoph Hellwig3b003152006-11-04 20:10:55 +01001017 req->buffer = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001018 if (blk_pc_request(req))
Boaz Harrosh30b0c372007-12-13 13:47:40 +02001019 sdb->length = req->data_len;
Christoph Hellwig3b003152006-11-04 20:10:55 +01001020 else
Boaz Harrosh30b0c372007-12-13 13:47:40 +02001021 sdb->length = req->nr_sectors << 9;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001022
1023 /*
1024 * Next, walk the list, and fill in the addresses and sizes of
1025 * each segment.
1026 */
Boaz Harrosh30b0c372007-12-13 13:47:40 +02001027 count = blk_rq_map_sg(req->q, req, sdb->table.sgl);
1028 BUG_ON(count > sdb->table.nents);
1029 sdb->table.nents = count;
Rusty Russell4a03d902007-11-19 11:28:48 +11001030 return BLKPREP_OK;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001031}
Boaz Harrosh6f9a35e2007-12-13 13:50:53 +02001032
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 */
1044int 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
1067err_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}
Boaz Harroshbb52d822007-12-13 16:14:27 -08001076EXPORT_SYMBOL(scsi_init_io);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001077
Christoph Hellwig3b003152006-11-04 20:10:55 +01001078static 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
James Bottomley7f9a6bc2007-08-04 10:06:25 -05001099int scsi_setup_blk_pc_cmnd(struct scsi_device *sdev, struct request *req)
James Bottomley7b163182005-12-15 20:17:02 -06001100{
Christoph Hellwig3b003152006-11-04 20:10:55 +01001101 struct scsi_cmnd *cmd;
James Bottomley7f9a6bc2007-08-04 10:06:25 -05001102 int ret = scsi_prep_state_check(sdev, req);
1103
1104 if (ret != BLKPREP_OK)
1105 return ret;
Christoph Hellwig3b003152006-11-04 20:10:55 +01001106
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
Boaz Harroshbb52d822007-12-13 16:14:27 -08001122 ret = scsi_init_io(cmd, GFP_ATOMIC);
Christoph Hellwig3b003152006-11-04 20:10:55 +01001123 if (unlikely(ret))
1124 return ret;
1125 } else {
1126 BUG_ON(req->data_len);
1127 BUG_ON(req->data);
1128
Boaz Harrosh30b0c372007-12-13 13:47:40 +02001129 memset(&cmd->sdb, 0, sizeof(cmd->sdb));
Christoph Hellwig3b003152006-11-04 20:10:55 +01001130 req->buffer = NULL;
1131 }
James Bottomley7b163182005-12-15 20:17:02 -06001132
Alexey Dobriyan46c43db2006-10-08 15:55:55 +04001133 BUILD_BUG_ON(sizeof(req->cmd) > sizeof(cmd->cmnd));
James Bottomley7b163182005-12-15 20:17:02 -06001134 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;
Christoph Hellwig3b003152006-11-04 20:10:55 +01001146 return BLKPREP_OK;
1147}
James Bottomley7f9a6bc2007-08-04 10:06:25 -05001148EXPORT_SYMBOL(scsi_setup_blk_pc_cmnd);
Christoph Hellwig3b003152006-11-04 20:10:55 +01001149
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 */
James Bottomley7f9a6bc2007-08-04 10:06:25 -05001155int scsi_setup_fs_cmnd(struct scsi_device *sdev, struct request *req)
Christoph Hellwig3b003152006-11-04 20:10:55 +01001156{
1157 struct scsi_cmnd *cmd;
James Bottomley7f9a6bc2007-08-04 10:06:25 -05001158 int ret = scsi_prep_state_check(sdev, req);
Christoph Hellwig3b003152006-11-04 20:10:55 +01001159
James Bottomley7f9a6bc2007-08-04 10:06:25 -05001160 if (ret != BLKPREP_OK)
1161 return ret;
Christoph Hellwig3b003152006-11-04 20:10:55 +01001162 /*
1163 * Filesystem requests must transfer data.
1164 */
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
Boaz Harroshbb52d822007-12-13 16:14:27 -08001171 return scsi_init_io(cmd, GFP_ATOMIC);
James Bottomley7b163182005-12-15 20:17:02 -06001172}
James Bottomley7f9a6bc2007-08-04 10:06:25 -05001173EXPORT_SYMBOL(scsi_setup_fs_cmnd);
James Bottomley7b163182005-12-15 20:17:02 -06001174
James Bottomley7f9a6bc2007-08-04 10:06:25 -05001175int scsi_prep_state_check(struct scsi_device *sdev, struct request *req)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001176{
Christoph Hellwig3b003152006-11-04 20:10:55 +01001177 int ret = BLKPREP_OK;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001178
1179 /*
Christoph Hellwig3b003152006-11-04 20:10:55 +01001180 * If the device is not in running state we will reject some
1181 * or all commands.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001182 */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001183 if (unlikely(sdev->sdev_state != SDEV_RUNNING)) {
Christoph Hellwig3b003152006-11-04 20:10:55 +01001184 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 */
James Bottomley9ccfc752005-10-02 11:45:08 -05001200 sdev_printk(KERN_ERR, sdev,
1201 "rejecting I/O to dead device\n");
Christoph Hellwig3b003152006-11-04 20:10:55 +01001202 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;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001221 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001222 }
James Bottomley7f9a6bc2007-08-04 10:06:25 -05001223 return ret;
1224}
1225EXPORT_SYMBOL(scsi_prep_state_check);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001226
James Bottomley7f9a6bc2007-08-04 10:06:25 -05001227int scsi_prep_return(struct request_queue *q, struct request *req, int ret)
1228{
1229 struct scsi_device *sdev = q->queuedata;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001230
Christoph Hellwig3b003152006-11-04 20:10:55 +01001231 switch (ret) {
1232 case BLKPREP_KILL:
1233 req->errors = DID_NO_CONNECT << 16;
James Bottomley7f9a6bc2007-08-04 10:06:25 -05001234 /* 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 }
Christoph Hellwig3b003152006-11-04 20:10:55 +01001241 break;
1242 case BLKPREP_DEFER:
1243 /*
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.
1247 */
1248 if (sdev->device_busy == 0)
1249 blk_plug_device(q);
1250 break;
1251 default:
1252 req->cmd_flags |= REQ_DONTPREP;
1253 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001254
Christoph Hellwig3b003152006-11-04 20:10:55 +01001255 return ret;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001256}
James Bottomley7f9a6bc2007-08-04 10:06:25 -05001257EXPORT_SYMBOL(scsi_prep_return);
1258
James Bottomley751bf4d2008-01-02 11:14:30 -06001259int scsi_prep_fn(struct request_queue *q, struct request *req)
James Bottomley7f9a6bc2007-08-04 10:06:25 -05001260{
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}
Linus Torvalds1da177e2005-04-16 15:20:36 -07001268
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 */
1275static 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,
James Bottomley9ccfc752005-10-02 11:45:08 -05001286 sdev_printk(KERN_INFO, sdev,
1287 "unblocking device at zero depth\n"));
Linus Torvalds1da177e2005-04-16 15:20:36 -07001288 } 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 */
1306static inline int scsi_host_queue_ready(struct request_queue *q,
1307 struct Scsi_Host *shost,
1308 struct scsi_device *sdev)
1309{
James Bottomley939647e2005-09-18 15:05:20 -05001310 if (scsi_host_in_recovery(shost))
Linus Torvalds1da177e2005-04-16 15:20:36 -07001311 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/*
James Bottomleye91442b2005-09-09 10:44:16 -05001340 * Kill a request for a dead device
Linus Torvalds1da177e2005-04-16 15:20:36 -07001341 */
Jens Axboe165125e2007-07-24 09:28:11 +02001342static void scsi_kill_request(struct request *req, struct request_queue *q)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001343{
James Bottomleye91442b2005-09-09 10:44:16 -05001344 struct scsi_cmnd *cmd = req->special;
Tejun Heoe36e0c82006-04-11 17:27:53 +09001345 struct scsi_device *sdev = cmd->device;
1346 struct Scsi_Host *shost = sdev->host;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001347
James Bottomley788ce432005-09-09 13:40:23 -05001348 blkdev_dequeue_request(req);
1349
James Bottomleye91442b2005-09-09 10:44:16 -05001350 if (unlikely(cmd == NULL)) {
1351 printk(KERN_CRIT "impossible request in %s.\n",
1352 __FUNCTION__);
1353 BUG();
Linus Torvalds1da177e2005-04-16 15:20:36 -07001354 }
James Bottomleye91442b2005-09-09 10:44:16 -05001355
1356 scsi_init_cmd_errh(cmd);
1357 cmd->result = DID_NO_CONNECT << 16;
1358 atomic_inc(&cmd->device->iorequest_cnt);
Tejun Heoe36e0c82006-04-11 17:27:53 +09001359
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
James Bottomleye91442b2005-09-09 10:44:16 -05001372 __scsi_done(cmd);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001373}
1374
Jens Axboe1aea6432006-01-09 16:03:03 +01001375static void scsi_softirq_done(struct request *rq)
1376{
1377 struct scsi_cmnd *cmd = rq->completion_data;
Brian King8884efa2006-02-24 17:10:04 -06001378 unsigned long wait_for = (cmd->allowed + 1) * cmd->timeout_per_command;
Jens Axboe1aea6432006-01-09 16:03:03 +01001379 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:
Christoph Hellwig596f4822007-01-02 12:56:00 +01001399 scsi_queue_insert(cmd, SCSI_MLQUEUE_EH_RETRY);
Jens Axboe1aea6432006-01-09 16:03:03 +01001400 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
Linus Torvalds1da177e2005-04-16 15:20:36 -07001410/*
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 */
1421static 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");
James Bottomleye91442b2005-09-09 10:44:16 -05001430 while ((req = elv_next_request(q)) != NULL)
1431 scsi_kill_request(req, q);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001432 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))) {
James Bottomley9ccfc752005-10-02 11:45:08 -05001456 sdev_printk(KERN_ERR, sdev,
1457 "rejecting I/O to offline device\n");
James Bottomleye91442b2005-09-09 10:44:16 -05001458 scsi_kill_request(req, q);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001459 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);
James Bottomleye91442b2005-09-09 10:44:16 -05001471 cmd = req->special;
1472 if (unlikely(cmd == NULL)) {
1473 printk(KERN_CRIT "impossible request in %s.\n"
1474 "please mail a stack trace to "
Jens Axboe4aff5e22006-08-10 08:44:47 +02001475 "linux-scsi@vger.kernel.org\n",
James Bottomleye91442b2005-09-09 10:44:16 -05001476 __FUNCTION__);
Jens Axboe4aff5e22006-08-10 08:44:47 +02001477 blk_dump_rq_flags(req, "foo");
James Bottomleye91442b2005-09-09 10:44:16 -05001478 BUG();
1479 }
Linus Torvalds1da177e2005-04-16 15:20:36 -07001480 spin_lock(shost->host_lock);
1481
1482 if (!scsi_host_queue_ready(q, shost, sdev))
1483 goto not_ready;
Tony Battersby25d7c362007-11-12 10:00:44 -05001484 if (scsi_target(sdev)->single_lun) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001485 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
Linus Torvalds1da177e2005-04-16 15:20:36 -07001498 /*
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
1546u64 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}
1566EXPORT_SYMBOL(scsi_calculate_bounce_limit);
1567
FUJITA Tomonorib58d9152006-11-16 19:24:10 +09001568struct request_queue *__scsi_alloc_queue(struct Scsi_Host *shost,
1569 request_fn_proc *request_fn)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001570{
Linus Torvalds1da177e2005-04-16 15:20:36 -07001571 struct request_queue *q;
1572
FUJITA Tomonorib58d9152006-11-16 19:24:10 +09001573 q = blk_init_queue(request_fn, NULL);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001574 if (!q)
1575 return NULL;
1576
Jens Axboea8474ce2007-08-07 09:02:51 +02001577 /*
1578 * this limit is imposed by hardware restrictions
1579 */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001580 blk_queue_max_hw_segments(q, shost->sg_tablesize);
James Bottomleyd3f46f32008-01-15 11:11:46 -06001581 blk_queue_max_phys_segments(q, SCSI_MAX_SG_CHAIN_SEGMENTS);
Jens Axboea8474ce2007-08-07 09:02:51 +02001582
Linus Torvalds1da177e2005-04-16 15:20:36 -07001583 blk_queue_max_sectors(q, shost->max_sectors);
1584 blk_queue_bounce_limit(q, scsi_calculate_bounce_limit(shost));
1585 blk_queue_segment_boundary(q, shost->dma_boundary);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001586
Linus Torvalds1da177e2005-04-16 15:20:36 -07001587 if (!shost->use_clustering)
1588 clear_bit(QUEUE_FLAG_CLUSTER, &q->queue_flags);
James Bottomley465ff312008-01-01 10:00:10 -06001589
1590 /*
1591 * set a reasonable default alignment on word boundaries: the
1592 * host and device may alter it using
1593 * blk_queue_update_dma_alignment() later.
1594 */
1595 blk_queue_dma_alignment(q, 0x03);
1596
Linus Torvalds1da177e2005-04-16 15:20:36 -07001597 return q;
1598}
FUJITA Tomonorib58d9152006-11-16 19:24:10 +09001599EXPORT_SYMBOL(__scsi_alloc_queue);
1600
1601struct request_queue *scsi_alloc_queue(struct scsi_device *sdev)
1602{
1603 struct request_queue *q;
1604
1605 q = __scsi_alloc_queue(sdev->host, scsi_request_fn);
1606 if (!q)
1607 return NULL;
1608
1609 blk_queue_prep_rq(q, scsi_prep_fn);
FUJITA Tomonorib58d9152006-11-16 19:24:10 +09001610 blk_queue_softirq_done(q, scsi_softirq_done);
1611 return q;
1612}
Linus Torvalds1da177e2005-04-16 15:20:36 -07001613
1614void scsi_free_queue(struct request_queue *q)
1615{
1616 blk_cleanup_queue(q);
1617}
1618
1619/*
1620 * Function: scsi_block_requests()
1621 *
1622 * Purpose: Utility function used by low-level drivers to prevent further
1623 * commands from being queued to the device.
1624 *
1625 * Arguments: shost - Host in question
1626 *
1627 * Returns: Nothing
1628 *
1629 * Lock status: No locks are assumed held.
1630 *
1631 * Notes: There is no timer nor any other means by which the requests
1632 * get unblocked other than the low-level driver calling
1633 * scsi_unblock_requests().
1634 */
1635void scsi_block_requests(struct Scsi_Host *shost)
1636{
1637 shost->host_self_blocked = 1;
1638}
1639EXPORT_SYMBOL(scsi_block_requests);
1640
1641/*
1642 * Function: scsi_unblock_requests()
1643 *
1644 * Purpose: Utility function used by low-level drivers to allow further
1645 * commands from being queued to the device.
1646 *
1647 * Arguments: shost - Host in question
1648 *
1649 * Returns: Nothing
1650 *
1651 * Lock status: No locks are assumed held.
1652 *
1653 * Notes: There is no timer nor any other means by which the requests
1654 * get unblocked other than the low-level driver calling
1655 * scsi_unblock_requests().
1656 *
1657 * This is done as an API function so that changes to the
1658 * internals of the scsi mid-layer won't require wholesale
1659 * changes to drivers that use this feature.
1660 */
1661void scsi_unblock_requests(struct Scsi_Host *shost)
1662{
1663 shost->host_self_blocked = 0;
1664 scsi_run_host_queues(shost);
1665}
1666EXPORT_SYMBOL(scsi_unblock_requests);
1667
1668int __init scsi_init_queue(void)
1669{
1670 int i;
1671
Mike Christieaa7b5cd2005-11-11 05:31:41 -06001672 scsi_io_context_cache = kmem_cache_create("scsi_io_context",
1673 sizeof(struct scsi_io_context),
Paul Mundt20c2df82007-07-20 10:11:58 +09001674 0, 0, NULL);
Mike Christieaa7b5cd2005-11-11 05:31:41 -06001675 if (!scsi_io_context_cache) {
1676 printk(KERN_ERR "SCSI: can't init scsi io context cache\n");
1677 return -ENOMEM;
1678 }
1679
Boaz Harrosh6f9a35e2007-12-13 13:50:53 +02001680 scsi_bidi_sdb_cache = kmem_cache_create("scsi_bidi_sdb",
1681 sizeof(struct scsi_data_buffer),
1682 0, 0, NULL);
1683 if (!scsi_bidi_sdb_cache) {
1684 printk(KERN_ERR "SCSI: can't init scsi bidi sdb cache\n");
FUJITA Tomonori3d9dd6e2008-01-25 23:25:14 +09001685 goto cleanup_io_context;
Boaz Harrosh6f9a35e2007-12-13 13:50:53 +02001686 }
1687
Linus Torvalds1da177e2005-04-16 15:20:36 -07001688 for (i = 0; i < SG_MEMPOOL_NR; i++) {
1689 struct scsi_host_sg_pool *sgp = scsi_sg_pools + i;
1690 int size = sgp->size * sizeof(struct scatterlist);
1691
1692 sgp->slab = kmem_cache_create(sgp->name, size, 0,
Paul Mundt20c2df82007-07-20 10:11:58 +09001693 SLAB_HWCACHE_ALIGN, NULL);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001694 if (!sgp->slab) {
1695 printk(KERN_ERR "SCSI: can't init sg slab %s\n",
1696 sgp->name);
FUJITA Tomonori3d9dd6e2008-01-25 23:25:14 +09001697 goto cleanup_bidi_sdb;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001698 }
1699
Matthew Dobson93d23412006-03-26 01:37:50 -08001700 sgp->pool = mempool_create_slab_pool(SG_MEMPOOL_SIZE,
1701 sgp->slab);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001702 if (!sgp->pool) {
1703 printk(KERN_ERR "SCSI: can't init sg mempool %s\n",
1704 sgp->name);
FUJITA Tomonori3d9dd6e2008-01-25 23:25:14 +09001705 goto cleanup_bidi_sdb;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001706 }
1707 }
1708
1709 return 0;
FUJITA Tomonori3d9dd6e2008-01-25 23:25:14 +09001710
1711cleanup_bidi_sdb:
1712 for (i = 0; i < SG_MEMPOOL_NR; i++) {
1713 struct scsi_host_sg_pool *sgp = scsi_sg_pools + i;
1714 if (sgp->pool)
1715 mempool_destroy(sgp->pool);
1716 if (sgp->slab)
1717 kmem_cache_destroy(sgp->slab);
1718 }
1719 kmem_cache_destroy(scsi_bidi_sdb_cache);
1720cleanup_io_context:
1721 kmem_cache_destroy(scsi_io_context_cache);
1722
1723 return -ENOMEM;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001724}
1725
1726void scsi_exit_queue(void)
1727{
1728 int i;
1729
Mike Christieaa7b5cd2005-11-11 05:31:41 -06001730 kmem_cache_destroy(scsi_io_context_cache);
FUJITA Tomonorib172b6e2008-01-25 23:25:13 +09001731 kmem_cache_destroy(scsi_bidi_sdb_cache);
Mike Christieaa7b5cd2005-11-11 05:31:41 -06001732
Linus Torvalds1da177e2005-04-16 15:20:36 -07001733 for (i = 0; i < SG_MEMPOOL_NR; i++) {
1734 struct scsi_host_sg_pool *sgp = scsi_sg_pools + i;
1735 mempool_destroy(sgp->pool);
1736 kmem_cache_destroy(sgp->slab);
1737 }
1738}
James Bottomley5baba832006-03-18 14:10:35 -06001739
1740/**
1741 * scsi_mode_select - issue a mode select
1742 * @sdev: SCSI device to be queried
1743 * @pf: Page format bit (1 == standard, 0 == vendor specific)
1744 * @sp: Save page bit (0 == don't save, 1 == save)
1745 * @modepage: mode page being requested
1746 * @buffer: request buffer (may not be smaller than eight bytes)
1747 * @len: length of request buffer.
1748 * @timeout: command timeout
1749 * @retries: number of retries before failing
1750 * @data: returns a structure abstracting the mode header data
Rob Landleyeb448202007-11-03 13:30:39 -05001751 * @sshdr: place to put sense data (or NULL if no sense to be collected).
James Bottomley5baba832006-03-18 14:10:35 -06001752 * must be SCSI_SENSE_BUFFERSIZE big.
1753 *
1754 * Returns zero if successful; negative error number or scsi
1755 * status on error
1756 *
1757 */
1758int
1759scsi_mode_select(struct scsi_device *sdev, int pf, int sp, int modepage,
1760 unsigned char *buffer, int len, int timeout, int retries,
1761 struct scsi_mode_data *data, struct scsi_sense_hdr *sshdr)
1762{
1763 unsigned char cmd[10];
1764 unsigned char *real_buffer;
1765 int ret;
1766
1767 memset(cmd, 0, sizeof(cmd));
1768 cmd[1] = (pf ? 0x10 : 0) | (sp ? 0x01 : 0);
1769
1770 if (sdev->use_10_for_ms) {
1771 if (len > 65535)
1772 return -EINVAL;
1773 real_buffer = kmalloc(8 + len, GFP_KERNEL);
1774 if (!real_buffer)
1775 return -ENOMEM;
1776 memcpy(real_buffer + 8, buffer, len);
1777 len += 8;
1778 real_buffer[0] = 0;
1779 real_buffer[1] = 0;
1780 real_buffer[2] = data->medium_type;
1781 real_buffer[3] = data->device_specific;
1782 real_buffer[4] = data->longlba ? 0x01 : 0;
1783 real_buffer[5] = 0;
1784 real_buffer[6] = data->block_descriptor_length >> 8;
1785 real_buffer[7] = data->block_descriptor_length;
1786
1787 cmd[0] = MODE_SELECT_10;
1788 cmd[7] = len >> 8;
1789 cmd[8] = len;
1790 } else {
1791 if (len > 255 || data->block_descriptor_length > 255 ||
1792 data->longlba)
1793 return -EINVAL;
1794
1795 real_buffer = kmalloc(4 + len, GFP_KERNEL);
1796 if (!real_buffer)
1797 return -ENOMEM;
1798 memcpy(real_buffer + 4, buffer, len);
1799 len += 4;
1800 real_buffer[0] = 0;
1801 real_buffer[1] = data->medium_type;
1802 real_buffer[2] = data->device_specific;
1803 real_buffer[3] = data->block_descriptor_length;
1804
1805
1806 cmd[0] = MODE_SELECT;
1807 cmd[4] = len;
1808 }
1809
1810 ret = scsi_execute_req(sdev, cmd, DMA_TO_DEVICE, real_buffer, len,
1811 sshdr, timeout, retries);
1812 kfree(real_buffer);
1813 return ret;
1814}
1815EXPORT_SYMBOL_GPL(scsi_mode_select);
1816
Linus Torvalds1da177e2005-04-16 15:20:36 -07001817/**
Rob Landleyeb448202007-11-03 13:30:39 -05001818 * scsi_mode_sense - issue a mode sense, falling back from 10 to six bytes if necessary.
James Bottomley1cf72692005-08-28 11:27:01 -05001819 * @sdev: SCSI device to be queried
Linus Torvalds1da177e2005-04-16 15:20:36 -07001820 * @dbd: set if mode sense will allow block descriptors to be returned
1821 * @modepage: mode page being requested
1822 * @buffer: request buffer (may not be smaller than eight bytes)
1823 * @len: length of request buffer.
1824 * @timeout: command timeout
1825 * @retries: number of retries before failing
1826 * @data: returns a structure abstracting the mode header data
Rob Landleyeb448202007-11-03 13:30:39 -05001827 * @sshdr: place to put sense data (or NULL if no sense to be collected).
James Bottomley1cf72692005-08-28 11:27:01 -05001828 * must be SCSI_SENSE_BUFFERSIZE big.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001829 *
1830 * Returns zero if unsuccessful, or the header offset (either 4
1831 * or 8 depending on whether a six or ten byte command was
1832 * issued) if successful.
Rob Landleyeb448202007-11-03 13:30:39 -05001833 */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001834int
James Bottomley1cf72692005-08-28 11:27:01 -05001835scsi_mode_sense(struct scsi_device *sdev, int dbd, int modepage,
Linus Torvalds1da177e2005-04-16 15:20:36 -07001836 unsigned char *buffer, int len, int timeout, int retries,
James Bottomley5baba832006-03-18 14:10:35 -06001837 struct scsi_mode_data *data, struct scsi_sense_hdr *sshdr)
1838{
Linus Torvalds1da177e2005-04-16 15:20:36 -07001839 unsigned char cmd[12];
1840 int use_10_for_ms;
1841 int header_length;
James Bottomley1cf72692005-08-28 11:27:01 -05001842 int result;
James Bottomleyea73a9f2005-08-28 11:33:52 -05001843 struct scsi_sense_hdr my_sshdr;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001844
1845 memset(data, 0, sizeof(*data));
1846 memset(&cmd[0], 0, 12);
1847 cmd[1] = dbd & 0x18; /* allows DBD and LLBA bits */
1848 cmd[2] = modepage;
1849
James Bottomleyea73a9f2005-08-28 11:33:52 -05001850 /* caller might not be interested in sense, but we need it */
1851 if (!sshdr)
1852 sshdr = &my_sshdr;
1853
Linus Torvalds1da177e2005-04-16 15:20:36 -07001854 retry:
James Bottomley1cf72692005-08-28 11:27:01 -05001855 use_10_for_ms = sdev->use_10_for_ms;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001856
1857 if (use_10_for_ms) {
1858 if (len < 8)
1859 len = 8;
1860
1861 cmd[0] = MODE_SENSE_10;
1862 cmd[8] = len;
1863 header_length = 8;
1864 } else {
1865 if (len < 4)
1866 len = 4;
1867
1868 cmd[0] = MODE_SENSE;
1869 cmd[4] = len;
1870 header_length = 4;
1871 }
1872
Linus Torvalds1da177e2005-04-16 15:20:36 -07001873 memset(buffer, 0, len);
1874
James Bottomley1cf72692005-08-28 11:27:01 -05001875 result = scsi_execute_req(sdev, cmd, DMA_FROM_DEVICE, buffer, len,
James Bottomleyea73a9f2005-08-28 11:33:52 -05001876 sshdr, timeout, retries);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001877
1878 /* This code looks awful: what it's doing is making sure an
1879 * ILLEGAL REQUEST sense return identifies the actual command
1880 * byte as the problem. MODE_SENSE commands can return
1881 * ILLEGAL REQUEST if the code page isn't supported */
1882
James Bottomley1cf72692005-08-28 11:27:01 -05001883 if (use_10_for_ms && !scsi_status_is_good(result) &&
1884 (driver_byte(result) & DRIVER_SENSE)) {
James Bottomleyea73a9f2005-08-28 11:33:52 -05001885 if (scsi_sense_valid(sshdr)) {
1886 if ((sshdr->sense_key == ILLEGAL_REQUEST) &&
1887 (sshdr->asc == 0x20) && (sshdr->ascq == 0)) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001888 /*
1889 * Invalid command operation code
1890 */
James Bottomley1cf72692005-08-28 11:27:01 -05001891 sdev->use_10_for_ms = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001892 goto retry;
1893 }
1894 }
1895 }
1896
James Bottomley1cf72692005-08-28 11:27:01 -05001897 if(scsi_status_is_good(result)) {
Al Viro6d73c852006-02-23 02:03:16 +01001898 if (unlikely(buffer[0] == 0x86 && buffer[1] == 0x0b &&
1899 (modepage == 6 || modepage == 8))) {
1900 /* Initio breakage? */
1901 header_length = 0;
1902 data->length = 13;
1903 data->medium_type = 0;
1904 data->device_specific = 0;
1905 data->longlba = 0;
1906 data->block_descriptor_length = 0;
1907 } else if(use_10_for_ms) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001908 data->length = buffer[0]*256 + buffer[1] + 2;
1909 data->medium_type = buffer[2];
1910 data->device_specific = buffer[3];
1911 data->longlba = buffer[4] & 0x01;
1912 data->block_descriptor_length = buffer[6]*256
1913 + buffer[7];
1914 } else {
1915 data->length = buffer[0] + 1;
1916 data->medium_type = buffer[1];
1917 data->device_specific = buffer[2];
1918 data->block_descriptor_length = buffer[3];
1919 }
Al Viro6d73c852006-02-23 02:03:16 +01001920 data->header_length = header_length;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001921 }
1922
James Bottomley1cf72692005-08-28 11:27:01 -05001923 return result;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001924}
1925EXPORT_SYMBOL(scsi_mode_sense);
1926
James Bottomley001aac22007-12-02 19:10:40 +02001927/**
1928 * scsi_test_unit_ready - test if unit is ready
1929 * @sdev: scsi device to change the state of.
1930 * @timeout: command timeout
1931 * @retries: number of retries before failing
1932 * @sshdr_external: Optional pointer to struct scsi_sense_hdr for
1933 * returning sense. Make sure that this is cleared before passing
1934 * in.
1935 *
1936 * Returns zero if unsuccessful or an error if TUR failed. For
1937 * removable media, a return of NOT_READY or UNIT_ATTENTION is
1938 * translated to success, with the ->changed flag updated.
1939 **/
Linus Torvalds1da177e2005-04-16 15:20:36 -07001940int
James Bottomley001aac22007-12-02 19:10:40 +02001941scsi_test_unit_ready(struct scsi_device *sdev, int timeout, int retries,
1942 struct scsi_sense_hdr *sshdr_external)
Linus Torvalds1da177e2005-04-16 15:20:36 -07001943{
Linus Torvalds1da177e2005-04-16 15:20:36 -07001944 char cmd[] = {
1945 TEST_UNIT_READY, 0, 0, 0, 0, 0,
1946 };
James Bottomley001aac22007-12-02 19:10:40 +02001947 struct scsi_sense_hdr *sshdr;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001948 int result;
James Bottomley001aac22007-12-02 19:10:40 +02001949
1950 if (!sshdr_external)
1951 sshdr = kzalloc(sizeof(*sshdr), GFP_KERNEL);
1952 else
1953 sshdr = sshdr_external;
1954
1955 /* try to eat the UNIT_ATTENTION if there are enough retries */
1956 do {
1957 result = scsi_execute_req(sdev, cmd, DMA_NONE, NULL, 0, sshdr,
1958 timeout, retries);
1959 } while ((driver_byte(result) & DRIVER_SENSE) &&
1960 sshdr && sshdr->sense_key == UNIT_ATTENTION &&
1961 --retries);
1962
1963 if (!sshdr)
1964 /* could not allocate sense buffer, so can't process it */
1965 return result;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001966
James Bottomley1cf72692005-08-28 11:27:01 -05001967 if ((driver_byte(result) & DRIVER_SENSE) && sdev->removable) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001968
James Bottomley001aac22007-12-02 19:10:40 +02001969 if ((scsi_sense_valid(sshdr)) &&
1970 ((sshdr->sense_key == UNIT_ATTENTION) ||
1971 (sshdr->sense_key == NOT_READY))) {
Linus Torvalds1da177e2005-04-16 15:20:36 -07001972 sdev->changed = 1;
James Bottomley1cf72692005-08-28 11:27:01 -05001973 result = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -07001974 }
1975 }
James Bottomley001aac22007-12-02 19:10:40 +02001976 if (!sshdr_external)
1977 kfree(sshdr);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001978 return result;
1979}
1980EXPORT_SYMBOL(scsi_test_unit_ready);
1981
1982/**
Rob Landleyeb448202007-11-03 13:30:39 -05001983 * scsi_device_set_state - Take the given device through the device state model.
Linus Torvalds1da177e2005-04-16 15:20:36 -07001984 * @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.
Rob Landleyeb448202007-11-03 13:30:39 -05001989 */
Linus Torvalds1da177e2005-04-16 15:20:36 -07001990int
1991scsi_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:
Alan Stern9ea72902006-06-23 14:25:34 -04002053 case SDEV_QUIESCE:
Linus Torvalds1da177e2005-04-16 15:20:36 -07002054 case SDEV_OFFLINE:
2055 case SDEV_BLOCK:
2056 break;
2057 default:
2058 goto illegal;
2059 }
2060 break;
2061
2062 case SDEV_DEL:
2063 switch (oldstate) {
Brian King309bd272006-06-27 11:10:43 -05002064 case SDEV_CREATED:
2065 case SDEV_RUNNING:
2066 case SDEV_OFFLINE:
Linus Torvalds1da177e2005-04-16 15:20:36 -07002067 case SDEV_CANCEL:
2068 break;
2069 default:
2070 goto illegal;
2071 }
2072 break;
2073
2074 }
2075 sdev->sdev_state = state;
2076 return 0;
2077
2078 illegal:
2079 SCSI_LOG_ERROR_RECOVERY(1,
James Bottomley9ccfc752005-10-02 11:45:08 -05002080 sdev_printk(KERN_ERR, sdev,
2081 "Illegal state transition %s->%s\n",
2082 scsi_device_state_name(oldstate),
2083 scsi_device_state_name(state))
Linus Torvalds1da177e2005-04-16 15:20:36 -07002084 );
2085 return -EINVAL;
2086}
2087EXPORT_SYMBOL(scsi_device_set_state);
2088
2089/**
Jeff Garzika341cd02007-10-29 17:15:22 -04002090 * sdev_evt_emit - emit a single SCSI device uevent
2091 * @sdev: associated SCSI device
2092 * @evt: event to emit
2093 *
2094 * Send a single uevent (scsi_event) to the associated scsi_device.
2095 */
2096static void scsi_evt_emit(struct scsi_device *sdev, struct scsi_event *evt)
2097{
2098 int idx = 0;
2099 char *envp[3];
2100
2101 switch (evt->evt_type) {
2102 case SDEV_EVT_MEDIA_CHANGE:
2103 envp[idx++] = "SDEV_MEDIA_CHANGE=1";
2104 break;
2105
2106 default:
2107 /* do nothing */
2108 break;
2109 }
2110
2111 envp[idx++] = NULL;
2112
2113 kobject_uevent_env(&sdev->sdev_gendev.kobj, KOBJ_CHANGE, envp);
2114}
2115
2116/**
2117 * sdev_evt_thread - send a uevent for each scsi event
2118 * @work: work struct for scsi_device
2119 *
2120 * Dispatch queued events to their associated scsi_device kobjects
2121 * as uevents.
2122 */
2123void scsi_evt_thread(struct work_struct *work)
2124{
2125 struct scsi_device *sdev;
2126 LIST_HEAD(event_list);
2127
2128 sdev = container_of(work, struct scsi_device, event_work);
2129
2130 while (1) {
2131 struct scsi_event *evt;
2132 struct list_head *this, *tmp;
2133 unsigned long flags;
2134
2135 spin_lock_irqsave(&sdev->list_lock, flags);
2136 list_splice_init(&sdev->event_list, &event_list);
2137 spin_unlock_irqrestore(&sdev->list_lock, flags);
2138
2139 if (list_empty(&event_list))
2140 break;
2141
2142 list_for_each_safe(this, tmp, &event_list) {
2143 evt = list_entry(this, struct scsi_event, node);
2144 list_del(&evt->node);
2145 scsi_evt_emit(sdev, evt);
2146 kfree(evt);
2147 }
2148 }
2149}
2150
2151/**
2152 * sdev_evt_send - send asserted event to uevent thread
2153 * @sdev: scsi_device event occurred on
2154 * @evt: event to send
2155 *
2156 * Assert scsi device event asynchronously.
2157 */
2158void sdev_evt_send(struct scsi_device *sdev, struct scsi_event *evt)
2159{
2160 unsigned long flags;
2161
2162 if (!test_bit(evt->evt_type, sdev->supported_events)) {
2163 kfree(evt);
2164 return;
2165 }
2166
2167 spin_lock_irqsave(&sdev->list_lock, flags);
2168 list_add_tail(&evt->node, &sdev->event_list);
2169 schedule_work(&sdev->event_work);
2170 spin_unlock_irqrestore(&sdev->list_lock, flags);
2171}
2172EXPORT_SYMBOL_GPL(sdev_evt_send);
2173
2174/**
2175 * sdev_evt_alloc - allocate a new scsi event
2176 * @evt_type: type of event to allocate
2177 * @gfpflags: GFP flags for allocation
2178 *
2179 * Allocates and returns a new scsi_event.
2180 */
2181struct scsi_event *sdev_evt_alloc(enum scsi_device_event evt_type,
2182 gfp_t gfpflags)
2183{
2184 struct scsi_event *evt = kzalloc(sizeof(struct scsi_event), gfpflags);
2185 if (!evt)
2186 return NULL;
2187
2188 evt->evt_type = evt_type;
2189 INIT_LIST_HEAD(&evt->node);
2190
2191 /* evt_type-specific initialization, if any */
2192 switch (evt_type) {
2193 case SDEV_EVT_MEDIA_CHANGE:
2194 default:
2195 /* do nothing */
2196 break;
2197 }
2198
2199 return evt;
2200}
2201EXPORT_SYMBOL_GPL(sdev_evt_alloc);
2202
2203/**
2204 * sdev_evt_send_simple - send asserted event to uevent thread
2205 * @sdev: scsi_device event occurred on
2206 * @evt_type: type of event to send
2207 * @gfpflags: GFP flags for allocation
2208 *
2209 * Assert scsi device event asynchronously, given an event type.
2210 */
2211void sdev_evt_send_simple(struct scsi_device *sdev,
2212 enum scsi_device_event evt_type, gfp_t gfpflags)
2213{
2214 struct scsi_event *evt = sdev_evt_alloc(evt_type, gfpflags);
2215 if (!evt) {
2216 sdev_printk(KERN_ERR, sdev, "event %d eaten due to OOM\n",
2217 evt_type);
2218 return;
2219 }
2220
2221 sdev_evt_send(sdev, evt);
2222}
2223EXPORT_SYMBOL_GPL(sdev_evt_send_simple);
2224
2225/**
Linus Torvalds1da177e2005-04-16 15:20:36 -07002226 * scsi_device_quiesce - Block user issued commands.
2227 * @sdev: scsi device to quiesce.
2228 *
2229 * This works by trying to transition to the SDEV_QUIESCE state
2230 * (which must be a legal transition). When the device is in this
2231 * state, only special requests will be accepted, all others will
2232 * be deferred. Since special requests may also be requeued requests,
2233 * a successful return doesn't guarantee the device will be
2234 * totally quiescent.
2235 *
2236 * Must be called with user context, may sleep.
2237 *
2238 * Returns zero if unsuccessful or an error if not.
Rob Landleyeb448202007-11-03 13:30:39 -05002239 */
Linus Torvalds1da177e2005-04-16 15:20:36 -07002240int
2241scsi_device_quiesce(struct scsi_device *sdev)
2242{
2243 int err = scsi_device_set_state(sdev, SDEV_QUIESCE);
2244 if (err)
2245 return err;
2246
2247 scsi_run_queue(sdev->request_queue);
2248 while (sdev->device_busy) {
2249 msleep_interruptible(200);
2250 scsi_run_queue(sdev->request_queue);
2251 }
2252 return 0;
2253}
2254EXPORT_SYMBOL(scsi_device_quiesce);
2255
2256/**
2257 * scsi_device_resume - Restart user issued commands to a quiesced device.
2258 * @sdev: scsi device to resume.
2259 *
2260 * Moves the device from quiesced back to running and restarts the
2261 * queues.
2262 *
2263 * Must be called with user context, may sleep.
Rob Landleyeb448202007-11-03 13:30:39 -05002264 */
Linus Torvalds1da177e2005-04-16 15:20:36 -07002265void
2266scsi_device_resume(struct scsi_device *sdev)
2267{
2268 if(scsi_device_set_state(sdev, SDEV_RUNNING))
2269 return;
2270 scsi_run_queue(sdev->request_queue);
2271}
2272EXPORT_SYMBOL(scsi_device_resume);
2273
2274static void
2275device_quiesce_fn(struct scsi_device *sdev, void *data)
2276{
2277 scsi_device_quiesce(sdev);
2278}
2279
2280void
2281scsi_target_quiesce(struct scsi_target *starget)
2282{
2283 starget_for_each_device(starget, NULL, device_quiesce_fn);
2284}
2285EXPORT_SYMBOL(scsi_target_quiesce);
2286
2287static void
2288device_resume_fn(struct scsi_device *sdev, void *data)
2289{
2290 scsi_device_resume(sdev);
2291}
2292
2293void
2294scsi_target_resume(struct scsi_target *starget)
2295{
2296 starget_for_each_device(starget, NULL, device_resume_fn);
2297}
2298EXPORT_SYMBOL(scsi_target_resume);
2299
2300/**
Rob Landleyeb448202007-11-03 13:30:39 -05002301 * scsi_internal_device_block - internal function to put a device temporarily into the SDEV_BLOCK state
Linus Torvalds1da177e2005-04-16 15:20:36 -07002302 * @sdev: device to block
2303 *
2304 * Block request made by scsi lld's to temporarily stop all
2305 * scsi commands on the specified device. Called from interrupt
2306 * or normal process context.
2307 *
2308 * Returns zero if successful or error if not
2309 *
2310 * Notes:
2311 * This routine transitions the device to the SDEV_BLOCK state
2312 * (which must be a legal transition). When the device is in this
2313 * state, all commands are deferred until the scsi lld reenables
2314 * the device with scsi_device_unblock or device_block_tmo fires.
2315 * This routine assumes the host_lock is held on entry.
Rob Landleyeb448202007-11-03 13:30:39 -05002316 */
Linus Torvalds1da177e2005-04-16 15:20:36 -07002317int
2318scsi_internal_device_block(struct scsi_device *sdev)
2319{
Jens Axboe165125e2007-07-24 09:28:11 +02002320 struct request_queue *q = sdev->request_queue;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002321 unsigned long flags;
2322 int err = 0;
2323
2324 err = scsi_device_set_state(sdev, SDEV_BLOCK);
2325 if (err)
2326 return err;
2327
2328 /*
2329 * The device has transitioned to SDEV_BLOCK. Stop the
2330 * block layer from calling the midlayer with this device's
2331 * request queue.
2332 */
2333 spin_lock_irqsave(q->queue_lock, flags);
2334 blk_stop_queue(q);
2335 spin_unlock_irqrestore(q->queue_lock, flags);
2336
2337 return 0;
2338}
2339EXPORT_SYMBOL_GPL(scsi_internal_device_block);
2340
2341/**
2342 * scsi_internal_device_unblock - resume a device after a block request
2343 * @sdev: device to resume
2344 *
2345 * Called by scsi lld's or the midlayer to restart the device queue
2346 * for the previously suspended scsi device. Called from interrupt or
2347 * normal process context.
2348 *
2349 * Returns zero if successful or error if not.
2350 *
2351 * Notes:
2352 * This routine transitions the device to the SDEV_RUNNING state
2353 * (which must be a legal transition) allowing the midlayer to
2354 * goose the queue for this device. This routine assumes the
2355 * host_lock is held upon entry.
Rob Landleyeb448202007-11-03 13:30:39 -05002356 */
Linus Torvalds1da177e2005-04-16 15:20:36 -07002357int
2358scsi_internal_device_unblock(struct scsi_device *sdev)
2359{
Jens Axboe165125e2007-07-24 09:28:11 +02002360 struct request_queue *q = sdev->request_queue;
Linus Torvalds1da177e2005-04-16 15:20:36 -07002361 int err;
2362 unsigned long flags;
2363
2364 /*
2365 * Try to transition the scsi device to SDEV_RUNNING
2366 * and goose the device queue if successful.
2367 */
2368 err = scsi_device_set_state(sdev, SDEV_RUNNING);
2369 if (err)
2370 return err;
2371
2372 spin_lock_irqsave(q->queue_lock, flags);
2373 blk_start_queue(q);
2374 spin_unlock_irqrestore(q->queue_lock, flags);
2375
2376 return 0;
2377}
2378EXPORT_SYMBOL_GPL(scsi_internal_device_unblock);
2379
2380static void
2381device_block(struct scsi_device *sdev, void *data)
2382{
2383 scsi_internal_device_block(sdev);
2384}
2385
2386static int
2387target_block(struct device *dev, void *data)
2388{
2389 if (scsi_is_target_device(dev))
2390 starget_for_each_device(to_scsi_target(dev), NULL,
2391 device_block);
2392 return 0;
2393}
2394
2395void
2396scsi_target_block(struct device *dev)
2397{
2398 if (scsi_is_target_device(dev))
2399 starget_for_each_device(to_scsi_target(dev), NULL,
2400 device_block);
2401 else
2402 device_for_each_child(dev, NULL, target_block);
2403}
2404EXPORT_SYMBOL_GPL(scsi_target_block);
2405
2406static void
2407device_unblock(struct scsi_device *sdev, void *data)
2408{
2409 scsi_internal_device_unblock(sdev);
2410}
2411
2412static int
2413target_unblock(struct device *dev, void *data)
2414{
2415 if (scsi_is_target_device(dev))
2416 starget_for_each_device(to_scsi_target(dev), NULL,
2417 device_unblock);
2418 return 0;
2419}
2420
2421void
2422scsi_target_unblock(struct device *dev)
2423{
2424 if (scsi_is_target_device(dev))
2425 starget_for_each_device(to_scsi_target(dev), NULL,
2426 device_unblock);
2427 else
2428 device_for_each_child(dev, NULL, target_unblock);
2429}
2430EXPORT_SYMBOL_GPL(scsi_target_unblock);
Guennadi Liakhovetskicdb8c2a2006-04-02 21:57:43 +02002431
2432/**
2433 * scsi_kmap_atomic_sg - find and atomically map an sg-elemnt
Rob Landleyeb448202007-11-03 13:30:39 -05002434 * @sgl: scatter-gather list
Guennadi Liakhovetskicdb8c2a2006-04-02 21:57:43 +02002435 * @sg_count: number of segments in sg
2436 * @offset: offset in bytes into sg, on return offset into the mapped area
2437 * @len: bytes to map, on return number of bytes mapped
2438 *
2439 * Returns virtual address of the start of the mapped page
2440 */
Jens Axboec6132da2007-10-16 11:08:49 +02002441void *scsi_kmap_atomic_sg(struct scatterlist *sgl, int sg_count,
Guennadi Liakhovetskicdb8c2a2006-04-02 21:57:43 +02002442 size_t *offset, size_t *len)
2443{
2444 int i;
2445 size_t sg_len = 0, len_complete = 0;
Jens Axboec6132da2007-10-16 11:08:49 +02002446 struct scatterlist *sg;
Guennadi Liakhovetskicdb8c2a2006-04-02 21:57:43 +02002447 struct page *page;
2448
Andrew Morton22cfefb2007-02-05 16:39:03 -08002449 WARN_ON(!irqs_disabled());
2450
Jens Axboec6132da2007-10-16 11:08:49 +02002451 for_each_sg(sgl, sg, sg_count, i) {
Guennadi Liakhovetskicdb8c2a2006-04-02 21:57:43 +02002452 len_complete = sg_len; /* Complete sg-entries */
Jens Axboec6132da2007-10-16 11:08:49 +02002453 sg_len += sg->length;
Guennadi Liakhovetskicdb8c2a2006-04-02 21:57:43 +02002454 if (sg_len > *offset)
2455 break;
2456 }
2457
2458 if (unlikely(i == sg_count)) {
Andrew Morton169e1a22006-04-18 21:09:08 -07002459 printk(KERN_ERR "%s: Bytes in sg: %zu, requested offset %zu, "
2460 "elements %d\n",
Guennadi Liakhovetskicdb8c2a2006-04-02 21:57:43 +02002461 __FUNCTION__, sg_len, *offset, sg_count);
2462 WARN_ON(1);
2463 return NULL;
2464 }
2465
2466 /* Offset starting from the beginning of first page in this sg-entry */
Jens Axboec6132da2007-10-16 11:08:49 +02002467 *offset = *offset - len_complete + sg->offset;
Guennadi Liakhovetskicdb8c2a2006-04-02 21:57:43 +02002468
2469 /* Assumption: contiguous pages can be accessed as "page + i" */
Jens Axboe45711f12007-10-22 21:19:53 +02002470 page = nth_page(sg_page(sg), (*offset >> PAGE_SHIFT));
Guennadi Liakhovetskicdb8c2a2006-04-02 21:57:43 +02002471 *offset &= ~PAGE_MASK;
2472
2473 /* Bytes in this sg-entry from *offset to the end of the page */
2474 sg_len = PAGE_SIZE - *offset;
2475 if (*len > sg_len)
2476 *len = sg_len;
2477
2478 return kmap_atomic(page, KM_BIO_SRC_IRQ);
2479}
2480EXPORT_SYMBOL(scsi_kmap_atomic_sg);
2481
2482/**
Rob Landleyeb448202007-11-03 13:30:39 -05002483 * scsi_kunmap_atomic_sg - atomically unmap a virtual address, previously mapped with scsi_kmap_atomic_sg
Guennadi Liakhovetskicdb8c2a2006-04-02 21:57:43 +02002484 * @virt: virtual address to be unmapped
2485 */
2486void scsi_kunmap_atomic_sg(void *virt)
2487{
2488 kunmap_atomic(virt, KM_BIO_SRC_IRQ);
2489}
2490EXPORT_SYMBOL(scsi_kunmap_atomic_sg);