Line data Source code
1 : /*
2 : * scsi.c Copyright (C) 1992 Drew Eckhardt
3 : * Copyright (C) 1993, 1994, 1995, 1999 Eric Youngdale
4 : * Copyright (C) 2002, 2003 Christoph Hellwig
5 : *
6 : * generic mid-level SCSI driver
7 : * Initial versions: Drew Eckhardt
8 : * Subsequent revisions: Eric Youngdale
9 : *
10 : * <drew@colorado.edu>
11 : *
12 : * Bug correction thanks go to :
13 : * Rik Faith <faith@cs.unc.edu>
14 : * Tommy Thorn <tthorn>
15 : * Thomas Wuensche <tw@fgb1.fgb.mw.tu-muenchen.de>
16 : *
17 : * Modified by Eric Youngdale eric@andante.org or ericy@gnu.ai.mit.edu to
18 : * add scatter-gather, multiple outstanding request, and other
19 : * enhancements.
20 : *
21 : * Native multichannel, wide scsi, /proc/scsi and hot plugging
22 : * support added by Michael Neuffer <mike@i-connect.net>
23 : *
24 : * Added request_module("scsi_hostadapter") for kerneld:
25 : * (Put an "alias scsi_hostadapter your_hostadapter" in /etc/modprobe.conf)
26 : * Bjorn Ekwall <bj0rn@blox.se>
27 : * (changed to kmod)
28 : *
29 : * Major improvements to the timeout, abort, and reset processing,
30 : * as well as performance modifications for large queue depths by
31 : * Leonard N. Zubkoff <lnz@dandelion.com>
32 : *
33 : * Converted cli() code to spinlocks, Ingo Molnar
34 : *
35 : * Jiffies wrap fixes (host->resetting), 3 Dec 1998 Andrea Arcangeli
36 : *
37 : * out_of_space hacks, D. Gilbert (dpg) 990608
38 : */
39 :
40 : #include <linux/module.h>
41 : #include <linux/moduleparam.h>
42 : #include <linux/kernel.h>
43 : #include <linux/timer.h>
44 : #include <linux/string.h>
45 : #include <linux/slab.h>
46 : #include <linux/blkdev.h>
47 : #include <linux/delay.h>
48 : #include <linux/init.h>
49 : #include <linux/completion.h>
50 : #include <linux/unistd.h>
51 : #include <linux/spinlock.h>
52 : #include <linux/kmod.h>
53 : #include <linux/interrupt.h>
54 : #include <linux/notifier.h>
55 : #include <linux/cpu.h>
56 : #include <linux/mutex.h>
57 :
58 : #include <scsi/scsi.h>
59 : #include <scsi/scsi_cmnd.h>
60 : #include <scsi/scsi_dbg.h>
61 : #include <scsi/scsi_device.h>
62 : #include <scsi/scsi_driver.h>
63 : #include <scsi/scsi_eh.h>
64 : #include <scsi/scsi_host.h>
65 : #include <scsi/scsi_tcq.h>
66 :
67 : #include "scsi_priv.h"
68 : #include "scsi_logging.h"
69 :
70 : static void scsi_done(struct scsi_cmnd *cmd);
71 :
72 : /*
73 : * Definitions and constants.
74 : */
75 :
76 : #define MIN_RESET_DELAY (2*HZ)
77 :
78 : /* Do not call reset on error if we just did a reset within 15 sec. */
79 : #define MIN_RESET_PERIOD (15*HZ)
80 :
81 : /*
82 : * Note - the initial logging level can be set here to log events at boot time.
83 : * After the system is up, you may enable logging via the /proc interface.
84 : */
85 : unsigned int scsi_logging_level;
86 : #if defined(CONFIG_SCSI_LOGGING)
87 : EXPORT_SYMBOL(scsi_logging_level);
88 : #endif
89 :
90 : /* NB: These are exposed through /proc/scsi/scsi and form part of the ABI.
91 : * You may not alter any existing entry (although adding new ones is
92 : * encouraged once assigned by ANSI/INCITS T10
93 : */
94 1 : static const char *const scsi_device_types[] = {
95 : "Direct-Access ",
96 : "Sequential-Access",
97 : "Printer ",
98 : "Processor ",
99 : "WORM ",
100 : "CD-ROM ",
101 : "Scanner ",
102 : "Optical Device ",
103 : "Medium Changer ",
104 : "Communications ",
105 : "ASC IT8 ",
106 : "ASC IT8 ",
107 : "RAID ",
108 : "Enclosure ",
109 : "Direct-Access-RBC",
110 : "Optical card ",
111 : "Bridge controller",
112 : "Object storage ",
113 : "Automation/Drive ",
114 : };
115 :
116 : /**
117 : * scsi_device_type - Return 17 char string indicating device type.
118 : * @type: type number to look up
119 : */
120 :
121 : const char * scsi_device_type(unsigned type)
122 : {
123 128 : if (type == 0x1e)
124 64 : return "Well-known LUN ";
125 128 : if (type == 0x1f)
126 64 : return "No Device ";
127 128 : if (type >= ARRAY_SIZE(scsi_device_types))
128 64 : return "Unknown ";
129 64 : return scsi_device_types[type];
130 : }
131 1 :
132 : EXPORT_SYMBOL(scsi_device_type);
133 :
134 : struct scsi_host_cmd_pool {
135 : struct kmem_cache *cmd_slab;
136 : struct kmem_cache *sense_slab;
137 : unsigned int users;
138 : char *cmd_name;
139 : char *sense_name;
140 : unsigned int slab_flags;
141 : gfp_t gfp_mask;
142 : };
143 :
144 1 : static struct scsi_host_cmd_pool scsi_cmd_pool = {
145 : .cmd_name = "scsi_cmd_cache",
146 : .sense_name = "scsi_sense_cache",
147 : .slab_flags = SLAB_HWCACHE_ALIGN,
148 : };
149 :
150 1 : static struct scsi_host_cmd_pool scsi_cmd_dma_pool = {
151 : .cmd_name = "scsi_cmd_cache(DMA)",
152 : .sense_name = "scsi_sense_cache(DMA)",
153 : .slab_flags = SLAB_HWCACHE_ALIGN|SLAB_CACHE_DMA,
154 : .gfp_mask = __GFP_DMA,
155 : };
156 :
157 1 : static DEFINE_MUTEX(host_cmd_pool_mutex);
158 :
159 : /**
160 : * scsi_pool_alloc_command - internal function to get a fully allocated command
161 : * @pool: slab pool to allocate the command from
162 : * @gfp_mask: mask for the allocation
163 : *
164 : * Returns a fully allocated command (with the allied sense buffer) or
165 : * NULL on failure
166 : */
167 : static struct scsi_cmnd *
168 : scsi_pool_alloc_command(struct scsi_host_cmd_pool *pool, gfp_t gfp_mask)
169 : {
170 : struct scsi_cmnd *cmd;
171 0 :
172 0 : cmd = kmem_cache_zalloc(pool->cmd_slab, gfp_mask | pool->gfp_mask);
173 0 : if (!cmd)
174 0 : return NULL;
175 :
176 0 : cmd->sense_buffer = kmem_cache_alloc(pool->sense_slab,
177 : gfp_mask | pool->gfp_mask);
178 0 : if (!cmd->sense_buffer) {
179 0 : kmem_cache_free(pool->cmd_slab, cmd);
180 0 : return NULL;
181 : }
182 :
183 0 : return cmd;
184 : }
185 :
186 : /**
187 : * scsi_pool_free_command - internal function to release a command
188 : * @pool: slab pool to allocate the command from
189 : * @cmd: command to release
190 : *
191 : * the command must previously have been allocated by
192 : * scsi_pool_alloc_command.
193 : */
194 : static void
195 : scsi_pool_free_command(struct scsi_host_cmd_pool *pool,
196 : struct scsi_cmnd *cmd)
197 : {
198 6 : if (cmd->prot_sdb)
199 4 : kmem_cache_free(scsi_sdb_cache, cmd->prot_sdb);
200 :
201 4 : kmem_cache_free(pool->sense_slab, cmd->sense_buffer);
202 2 : kmem_cache_free(pool->cmd_slab, cmd);
203 2 : }
204 :
205 : /**
206 : * scsi_host_alloc_command - internal function to allocate command
207 : * @shost: SCSI host whose pool to allocate from
208 : * @gfp_mask: mask for the allocation
209 : *
210 : * Returns a fully allocated command with sense buffer and protection
211 : * data buffer (where applicable) or NULL on failure
212 : */
213 : static struct scsi_cmnd *
214 : scsi_host_alloc_command(struct Scsi_Host *shost, gfp_t gfp_mask)
215 : {
216 0 : struct scsi_cmnd *cmd;
217 0 :
218 0 : cmd = scsi_pool_alloc_command(shost->cmd_pool, gfp_mask);
219 0 : if (!cmd)
220 0 : return NULL;
221 :
222 0 : if (scsi_host_get_prot(shost) >= SHOST_DIX_TYPE0_PROTECTION) {
223 0 : cmd->prot_sdb = kmem_cache_zalloc(scsi_sdb_cache, gfp_mask);
224 :
225 0 : if (!cmd->prot_sdb) {
226 0 : scsi_pool_free_command(shost->cmd_pool, cmd);
227 0 : return NULL;
228 : }
229 : }
230 :
231 0 : return cmd;
232 : }
233 :
234 : /**
235 : * __scsi_get_command - Allocate a struct scsi_cmnd
236 : * @shost: host to transmit command
237 : * @gfp_mask: allocation mask
238 : *
239 : * Description: allocate a struct scsi_cmd from host's slab, recycling from the
240 : * host's free_list if necessary.
241 : */
242 : struct scsi_cmnd *__scsi_get_command(struct Scsi_Host *shost, gfp_t gfp_mask)
243 : {
244 0 : struct scsi_cmnd *cmd = scsi_host_alloc_command(shost, gfp_mask);
245 0 :
246 0 : if (unlikely(!cmd)) {
247 0 : unsigned long flags;
248 0 :
249 0 : spin_lock_irqsave(&shost->free_list_lock, flags);
250 0 : if (likely(!list_empty(&shost->free_list))) {
251 0 : cmd = list_entry(shost->free_list.next,
252 0 : struct scsi_cmnd, list);
253 0 : list_del_init(&cmd->list);
254 : }
255 0 : spin_unlock_irqrestore(&shost->free_list_lock, flags);
256 :
257 0 : if (cmd) {
258 : void *buf, *prot;
259 :
260 0 : buf = cmd->sense_buffer;
261 0 : prot = cmd->prot_sdb;
262 :
263 0 : memset(cmd, 0, sizeof(*cmd));
264 :
265 0 : cmd->sense_buffer = buf;
266 0 : cmd->prot_sdb = prot;
267 : }
268 : }
269 :
270 0 : return cmd;
271 : }
272 : EXPORT_SYMBOL_GPL(__scsi_get_command);
273 :
274 : /**
275 : * scsi_get_command - Allocate and setup a scsi command block
276 : * @dev: parent scsi device
277 : * @gfp_mask: allocator flags
278 : *
279 : * Returns: The allocated scsi command structure.
280 : */
281 : struct scsi_cmnd *scsi_get_command(struct scsi_device *dev, gfp_t gfp_mask)
282 : {
283 0 : struct scsi_cmnd *cmd;
284 0 :
285 0 : /* Bail if we can't get a reference to the device */
286 0 : if (!get_device(&dev->sdev_gendev))
287 0 : return NULL;
288 :
289 0 : cmd = __scsi_get_command(dev->host, gfp_mask);
290 :
291 0 : if (likely(cmd != NULL)) {
292 : unsigned long flags;
293 :
294 0 : cmd->device = dev;
295 0 : INIT_LIST_HEAD(&cmd->list);
296 0 : spin_lock_irqsave(&dev->list_lock, flags);
297 0 : list_add_tail(&cmd->list, &dev->cmd_list);
298 0 : spin_unlock_irqrestore(&dev->list_lock, flags);
299 0 : cmd->jiffies_at_alloc = jiffies;
300 : } else
301 0 : put_device(&dev->sdev_gendev);
302 :
303 0 : return cmd;
304 : }
305 : EXPORT_SYMBOL(scsi_get_command);
306 :
307 : /**
308 : * __scsi_put_command - Free a struct scsi_cmnd
309 : * @shost: dev->host
310 : * @cmd: Command to free
311 : * @dev: parent scsi device
312 : */
313 : void __scsi_put_command(struct Scsi_Host *shost, struct scsi_cmnd *cmd,
314 : struct device *dev)
315 0 : {
316 0 : unsigned long flags;
317 0 :
318 0 : /* changing locks here, don't need to restore the irq state */
319 0 : spin_lock_irqsave(&shost->free_list_lock, flags);
320 0 : if (unlikely(list_empty(&shost->free_list))) {
321 0 : list_add(&cmd->list, &shost->free_list);
322 0 : cmd = NULL;
323 : }
324 0 : spin_unlock_irqrestore(&shost->free_list_lock, flags);
325 :
326 0 : if (likely(cmd != NULL))
327 0 : scsi_pool_free_command(shost->cmd_pool, cmd);
328 :
329 0 : put_device(dev);
330 0 : }
331 : EXPORT_SYMBOL(__scsi_put_command);
332 :
333 : /**
334 : * scsi_put_command - Free a scsi command block
335 : * @cmd: command block to free
336 : *
337 : * Returns: Nothing.
338 : *
339 : * Notes: The command must not belong to any lists.
340 : */
341 : void scsi_put_command(struct scsi_cmnd *cmd)
342 : {
343 0 : struct scsi_device *sdev = cmd->device;
344 0 : unsigned long flags;
345 0 :
346 0 : /* serious error if the command hasn't come from a device list */
347 0 : spin_lock_irqsave(&cmd->device->list_lock, flags);
348 0 : BUG_ON(list_empty(&cmd->list));
349 0 : list_del_init(&cmd->list);
350 0 : spin_unlock_irqrestore(&cmd->device->list_lock, flags);
351 :
352 0 : __scsi_put_command(cmd->device->host, cmd, &sdev->sdev_gendev);
353 0 : }
354 : EXPORT_SYMBOL(scsi_put_command);
355 :
356 : static struct scsi_host_cmd_pool *scsi_get_host_cmd_pool(gfp_t gfp_mask)
357 : {
358 0 : struct scsi_host_cmd_pool *retval = NULL, *pool;
359 0 : /*
360 : * Select a command slab for this host and create it if not
361 : * yet existent.
362 : */
363 0 : mutex_lock(&host_cmd_pool_mutex);
364 0 : pool = (gfp_mask & __GFP_DMA) ? &scsi_cmd_dma_pool :
365 : &scsi_cmd_pool;
366 0 : if (!pool->users) {
367 0 : pool->cmd_slab = kmem_cache_create(pool->cmd_name,
368 : sizeof(struct scsi_cmnd), 0,
369 : pool->slab_flags, NULL);
370 0 : if (!pool->cmd_slab)
371 0 : goto fail;
372 :
373 0 : pool->sense_slab = kmem_cache_create(pool->sense_name,
374 : SCSI_SENSE_BUFFERSIZE, 0,
375 : pool->slab_flags, NULL);
376 0 : if (!pool->sense_slab) {
377 0 : kmem_cache_destroy(pool->cmd_slab);
378 0 : goto fail;
379 : }
380 : }
381 :
382 0 : pool->users++;
383 0 : retval = pool;
384 0 : fail:
385 0 : mutex_unlock(&host_cmd_pool_mutex);
386 0 : return retval;
387 : }
388 :
389 : static void scsi_put_host_cmd_pool(gfp_t gfp_mask)
390 : {
391 2 : struct scsi_host_cmd_pool *pool;
392 2 :
393 2 : mutex_lock(&host_cmd_pool_mutex);
394 12 : pool = (gfp_mask & __GFP_DMA) ? &scsi_cmd_dma_pool :
395 : &scsi_cmd_pool;
396 : /*
397 : * This may happen if a driver has a mismatched get and put
398 : * of the command pool; the driver should be implicated in
399 : * the stack trace
400 : */
401 12 : BUG_ON(pool->users == 0);
402 :
403 6 : if (!--pool->users) {
404 2 : kmem_cache_destroy(pool->cmd_slab);
405 2 : kmem_cache_destroy(pool->sense_slab);
406 : }
407 2 : mutex_unlock(&host_cmd_pool_mutex);
408 2 : }
409 :
410 : /**
411 : * scsi_allocate_command - get a fully allocated SCSI command
412 : * @gfp_mask: allocation mask
413 : *
414 : * This function is for use outside of the normal host based pools.
415 : * It allocates the relevant command and takes an additional reference
416 : * on the pool it used. This function *must* be paired with
417 : * scsi_free_command which also has the identical mask, otherwise the
418 : * free pool counts will eventually go wrong and you'll trigger a bug.
419 : *
420 : * This function should *only* be used by drivers that need a static
421 : * command allocation at start of day for internal functions.
422 : */
423 : struct scsi_cmnd *scsi_allocate_command(gfp_t gfp_mask)
424 : {
425 0 : struct scsi_host_cmd_pool *pool = scsi_get_host_cmd_pool(gfp_mask);
426 0 :
427 0 : if (!pool)
428 0 : return NULL;
429 :
430 0 : return scsi_pool_alloc_command(pool, gfp_mask);
431 : }
432 : EXPORT_SYMBOL(scsi_allocate_command);
433 :
434 : /**
435 : * scsi_free_command - free a command allocated by scsi_allocate_command
436 : * @gfp_mask: mask used in the original allocation
437 : * @cmd: command to free
438 : *
439 : * Note: using the original allocation mask is vital because that's
440 : * what determines which command pool we use to free the command. Any
441 : * mismatch will cause the system to BUG eventually.
442 : */
443 : void scsi_free_command(gfp_t gfp_mask, struct scsi_cmnd *cmd)
444 : {
445 0 : struct scsi_host_cmd_pool *pool = scsi_get_host_cmd_pool(gfp_mask);
446 0 :
447 0 : /*
448 : * this could trigger if the mask to scsi_allocate_command
449 : * doesn't match this mask. Otherwise we're guaranteed that this
450 : * succeeds because scsi_allocate_command must have taken a reference
451 : * on the pool
452 : */
453 0 : BUG_ON(!pool);
454 :
455 0 : scsi_pool_free_command(pool, cmd);
456 : /*
457 : * scsi_put_host_cmd_pool is called twice; once to release the
458 : * reference we took above, and once to release the reference
459 : * originally taken by scsi_allocate_command
460 : */
461 0 : scsi_put_host_cmd_pool(gfp_mask);
462 0 : scsi_put_host_cmd_pool(gfp_mask);
463 0 : }
464 : EXPORT_SYMBOL(scsi_free_command);
465 :
466 : /**
467 : * scsi_setup_command_freelist - Setup the command freelist for a scsi host.
468 : * @shost: host to allocate the freelist for.
469 : *
470 : * Description: The command freelist protects against system-wide out of memory
471 : * deadlock by preallocating one SCSI command structure for each host, so the
472 : * system can always write to a swap file on a device associated with that host.
473 : *
474 : * Returns: Nothing.
475 : */
476 : int scsi_setup_command_freelist(struct Scsi_Host *shost)
477 : {
478 0 : struct scsi_cmnd *cmd;
479 0 : const gfp_t gfp_mask = shost->unchecked_isa_dma ? GFP_DMA : GFP_KERNEL;
480 0 :
481 0 : spin_lock_init(&shost->free_list_lock);
482 0 : INIT_LIST_HEAD(&shost->free_list);
483 :
484 0 : shost->cmd_pool = scsi_get_host_cmd_pool(gfp_mask);
485 :
486 0 : if (!shost->cmd_pool)
487 0 : return -ENOMEM;
488 :
489 : /*
490 : * Get one backup command for this host.
491 : */
492 0 : cmd = scsi_host_alloc_command(shost, gfp_mask);
493 0 : if (!cmd) {
494 0 : scsi_put_host_cmd_pool(gfp_mask);
495 0 : shost->cmd_pool = NULL;
496 0 : return -ENOMEM;
497 : }
498 0 : list_add(&cmd->list, &shost->free_list);
499 0 : return 0;
500 : }
501 :
502 : /**
503 : * scsi_destroy_command_freelist - Release the command freelist for a scsi host.
504 : * @shost: host whose freelist is going to be destroyed
505 : */
506 : void scsi_destroy_command_freelist(struct Scsi_Host *shost)
507 : {
508 2 : /*
509 2 : * If cmd_pool is NULL the free list was not initialized, so
510 2 : * do not attempt to release resources.
511 : */
512 6 : if (!shost->cmd_pool)
513 2 : return;
514 :
515 10 : while (!list_empty(&shost->free_list)) {
516 2 : struct scsi_cmnd *cmd;
517 2 :
518 4 : cmd = list_entry(shost->free_list.next, struct scsi_cmnd, list);
519 4 : list_del_init(&cmd->list);
520 4 : scsi_pool_free_command(shost->cmd_pool, cmd);
521 : }
522 4 : shost->cmd_pool = NULL;
523 14 : scsi_put_host_cmd_pool(shost->unchecked_isa_dma ? GFP_DMA : GFP_KERNEL);
524 2 : }
525 :
526 : #ifdef CONFIG_SCSI_LOGGING
527 : void scsi_log_send(struct scsi_cmnd *cmd)
528 : {
529 : unsigned int level;
530 :
531 : /*
532 : * If ML QUEUE log level is greater than or equal to:
533 : *
534 : * 1: nothing (match completion)
535 : *
536 : * 2: log opcode + command of all commands
537 : *
538 : * 3: same as 2 plus dump cmd address
539 : *
540 : * 4: same as 3 plus dump extra junk
541 : */
542 : if (unlikely(scsi_logging_level)) {
543 : level = SCSI_LOG_LEVEL(SCSI_LOG_MLQUEUE_SHIFT,
544 : SCSI_LOG_MLQUEUE_BITS);
545 : if (level > 1) {
546 : scmd_printk(KERN_INFO, cmd, "Send: ");
547 : if (level > 2)
548 : printk("0x%p ", cmd);
549 : printk("\n");
550 : scsi_print_command(cmd);
551 : if (level > 3) {
552 : printk(KERN_INFO "buffer = 0x%p, bufflen = %d,"
553 : " queuecommand 0x%p\n",
554 : scsi_sglist(cmd), scsi_bufflen(cmd),
555 : cmd->device->host->hostt->queuecommand);
556 :
557 : }
558 : }
559 : }
560 : }
561 :
562 : void scsi_log_completion(struct scsi_cmnd *cmd, int disposition)
563 : {
564 : unsigned int level;
565 :
566 : /*
567 : * If ML COMPLETE log level is greater than or equal to:
568 : *
569 : * 1: log disposition, result, opcode + command, and conditionally
570 : * sense data for failures or non SUCCESS dispositions.
571 : *
572 : * 2: same as 1 but for all command completions.
573 : *
574 : * 3: same as 2 plus dump cmd address
575 : *
576 : * 4: same as 3 plus dump extra junk
577 : */
578 : if (unlikely(scsi_logging_level)) {
579 : level = SCSI_LOG_LEVEL(SCSI_LOG_MLCOMPLETE_SHIFT,
580 : SCSI_LOG_MLCOMPLETE_BITS);
581 : if (((level > 0) && (cmd->result || disposition != SUCCESS)) ||
582 : (level > 1)) {
583 : scmd_printk(KERN_INFO, cmd, "Done: ");
584 : if (level > 2)
585 : printk("0x%p ", cmd);
586 : /*
587 : * Dump truncated values, so we usually fit within
588 : * 80 chars.
589 : */
590 : switch (disposition) {
591 : case SUCCESS:
592 : printk("SUCCESS\n");
593 : break;
594 : case NEEDS_RETRY:
595 : printk("RETRY\n");
596 : break;
597 : case ADD_TO_MLQUEUE:
598 : printk("MLQUEUE\n");
599 : break;
600 : case FAILED:
601 : printk("FAILED\n");
602 : break;
603 : case TIMEOUT_ERROR:
604 : /*
605 : * If called via scsi_times_out.
606 : */
607 : printk("TIMEOUT\n");
608 : break;
609 : default:
610 : printk("UNKNOWN\n");
611 : }
612 : scsi_print_result(cmd);
613 : scsi_print_command(cmd);
614 : if (status_byte(cmd->result) & CHECK_CONDITION)
615 : scsi_print_sense("", cmd);
616 : if (level > 3)
617 : scmd_printk(KERN_INFO, cmd,
618 : "scsi host busy %d failed %d\n",
619 : cmd->device->host->host_busy,
620 : cmd->device->host->host_failed);
621 : }
622 : }
623 : }
624 : #endif
625 :
626 : /**
627 : * scsi_cmd_get_serial - Assign a serial number to a command
628 : * @host: the scsi host
629 : * @cmd: command to assign serial number to
630 : *
631 : * Description: a serial number identifies a request for error recovery
632 : * and debugging purposes. Protected by the Host_Lock of host.
633 : */
634 : static inline void scsi_cmd_get_serial(struct Scsi_Host *host, struct scsi_cmnd *cmd)
635 : {
636 0 : cmd->serial_number = host->cmd_serial_number++;
637 0 : if (cmd->serial_number == 0)
638 0 : cmd->serial_number = host->cmd_serial_number++;
639 0 : }
640 :
641 : /**
642 : * scsi_dispatch_command - Dispatch a command to the low-level driver.
643 : * @cmd: command block we are dispatching.
644 : *
645 : * Return: nonzero return request was rejected and device's queue needs to be
646 : * plugged.
647 : */
648 : int scsi_dispatch_cmd(struct scsi_cmnd *cmd)
649 : {
650 0 : struct Scsi_Host *host = cmd->device->host;
651 0 : unsigned long flags = 0;
652 0 : unsigned long timeout;
653 0 : int rtn = 0;
654 0 :
655 0 : atomic_inc(&cmd->device->iorequest_cnt);
656 0 :
657 0 : /* check if the device is still usable */
658 0 : if (unlikely(cmd->device->sdev_state == SDEV_DEL)) {
659 0 : /* in SDEV_DEL we error all commands. DID_NO_CONNECT
660 0 : * returns an immediate error upwards, and signals
661 0 : * that the device is no longer present */
662 0 : cmd->result = DID_NO_CONNECT << 16;
663 0 : scsi_done(cmd);
664 : /* return 0 (because the command has been processed) */
665 0 : goto out;
666 : }
667 :
668 : /* Check to see if the scsi lld made this device blocked. */
669 0 : if (unlikely(scsi_device_blocked(cmd->device))) {
670 : /*
671 : * in blocked state, the command is just put back on
672 : * the device queue. The suspend state has already
673 : * blocked the queue so future requests should not
674 : * occur until the device transitions out of the
675 : * suspend state.
676 : */
677 :
678 0 : scsi_queue_insert(cmd, SCSI_MLQUEUE_DEVICE_BUSY);
679 :
680 : SCSI_LOG_MLQUEUE(3, printk("queuecommand : device blocked \n"));
681 :
682 : /*
683 : * NOTE: rtn is still zero here because we don't need the
684 : * queue to be plugged on return (it's already stopped)
685 : */
686 0 : goto out;
687 : }
688 :
689 : /*
690 : * If SCSI-2 or lower, store the LUN value in cmnd.
691 : */
692 0 : if (cmd->device->scsi_level <= SCSI_2 &&
693 : cmd->device->scsi_level != SCSI_UNKNOWN) {
694 0 : cmd->cmnd[1] = (cmd->cmnd[1] & 0x1f) |
695 : (cmd->device->lun << 5 & 0xe0);
696 : }
697 :
698 : /*
699 : * We will wait MIN_RESET_DELAY clock ticks after the last reset so
700 : * we can avoid the drive not being ready.
701 : */
702 0 : timeout = host->last_reset + MIN_RESET_DELAY;
703 :
704 0 : if (host->resetting && time_before(jiffies, timeout)) {
705 0 : int ticks_remaining = timeout - jiffies;
706 : /*
707 : * NOTE: This may be executed from within an interrupt
708 : * handler! This is bad, but for now, it'll do. The irq
709 : * level of the interrupt handler has been masked out by the
710 : * platform dependent interrupt handling code already, so the
711 : * sti() here will not cause another call to the SCSI host's
712 : * interrupt handler (assuming there is one irq-level per
713 : * host).
714 : */
715 0 : while (--ticks_remaining >= 0)
716 0 : mdelay(1 + 999 / HZ);
717 0 : host->resetting = 0;
718 : }
719 :
720 0 : scsi_log_send(cmd);
721 :
722 : /*
723 : * Before we queue this command, check if the command
724 0 : * length exceeds what the host adapter can handle.
725 : */
726 0 : if (cmd->cmd_len > cmd->device->host->max_cmd_len) {
727 : SCSI_LOG_MLQUEUE(3,
728 : printk("queuecommand : command too long. "
729 : "cdb_size=%d host->max_cmd_len=%d\n",
730 : cmd->cmd_len, cmd->device->host->max_cmd_len));
731 0 : cmd->result = (DID_ABORT << 16);
732 :
733 0 : scsi_done(cmd);
734 0 : goto out;
735 : }
736 :
737 0 : spin_lock_irqsave(host->host_lock, flags);
738 : /*
739 : * AK: unlikely race here: for some reason the timer could
740 : * expire before the serial number is set up below.
741 : *
742 : * TODO: kill serial or move to blk layer
743 : */
744 0 : scsi_cmd_get_serial(host, cmd);
745 :
746 0 : if (unlikely(host->shost_state == SHOST_DEL)) {
747 0 : cmd->result = (DID_NO_CONNECT << 16);
748 0 : scsi_done(cmd);
749 : } else {
750 0 : rtn = host->hostt->queuecommand(cmd, scsi_done);
751 : }
752 0 : spin_unlock_irqrestore(host->host_lock, flags);
753 0 : if (rtn) {
754 0 : if (rtn != SCSI_MLQUEUE_DEVICE_BUSY &&
755 : rtn != SCSI_MLQUEUE_TARGET_BUSY)
756 0 : rtn = SCSI_MLQUEUE_HOST_BUSY;
757 :
758 0 : scsi_queue_insert(cmd, rtn);
759 :
760 : SCSI_LOG_MLQUEUE(3,
761 : printk("queuecommand : request rejected\n"));
762 : }
763 0 :
764 : out:
765 : SCSI_LOG_MLQUEUE(3, printk("leaving scsi_dispatch_cmnd()\n"));
766 0 : return rtn;
767 : }
768 :
769 : /**
770 : * scsi_done - Enqueue the finished SCSI command into the done queue.
771 : * @cmd: The SCSI Command for which a low-level device driver (LLDD) gives
772 : * ownership back to SCSI Core -- i.e. the LLDD has finished with it.
773 : *
774 : * Description: This function is the mid-level's (SCSI Core) interrupt routine,
775 : * which regains ownership of the SCSI command (de facto) from a LLDD, and
776 : * enqueues the command to the done queue for further processing.
777 : *
778 : * This is the producer of the done queue who enqueues at the tail.
779 : *
780 : * This function is interrupt context safe.
781 : */
782 : static void scsi_done(struct scsi_cmnd *cmd)
783 : {
784 0 : blk_complete_request(cmd->request);
785 0 : }
786 :
787 : /* Move this to a header if it becomes more generally useful */
788 : static struct scsi_driver *scsi_cmd_to_driver(struct scsi_cmnd *cmd)
789 : {
790 0 : return *(struct scsi_driver **)cmd->request->rq_disk->private_data;
791 : }
792 :
793 : /**
794 : * scsi_finish_command - cleanup and pass command back to upper layer
795 : * @cmd: the command
796 : *
797 : * Description: Pass command off to upper layer for finishing of I/O
798 : * request, waking processes that are waiting on results,
799 : * etc.
800 : */
801 : void scsi_finish_command(struct scsi_cmnd *cmd)
802 : {
803 0 : struct scsi_device *sdev = cmd->device;
804 0 : struct scsi_target *starget = scsi_target(sdev);
805 0 : struct Scsi_Host *shost = sdev->host;
806 0 : struct scsi_driver *drv;
807 0 : unsigned int good_bytes;
808 0 :
809 0 : scsi_device_unbusy(sdev);
810 0 :
811 0 : /*
812 : * Clear the flags which say that the device/host is no longer
813 : * capable of accepting new commands. These are set in scsi_queue.c
814 : * for both the queue full condition on a device, and for a
815 : * host full condition on the host.
816 : *
817 : * XXX(hch): What about locking?
818 : */
819 0 : shost->host_blocked = 0;
820 0 : starget->target_blocked = 0;
821 0 : sdev->device_blocked = 0;
822 :
823 : /*
824 : * If we have valid sense information, then some kind of recovery
825 : * must have taken place. Make a note of this.
826 : */
827 0 : if (SCSI_SENSE_VALID(cmd))
828 0 : cmd->result |= (DRIVER_SENSE << 24);
829 :
830 : SCSI_LOG_MLCOMPLETE(4, sdev_printk(KERN_INFO, sdev,
831 : "Notifying upper driver of completion "
832 : "(result %x)\n", cmd->result));
833 :
834 0 : good_bytes = scsi_bufflen(cmd);
835 0 : if (cmd->request->cmd_type != REQ_TYPE_BLOCK_PC) {
836 0 : int old_good_bytes = good_bytes;
837 0 : drv = scsi_cmd_to_driver(cmd);
838 0 : if (drv->done)
839 0 : good_bytes = drv->done(cmd);
840 : /*
841 : * USB may not give sense identifying bad sector and
842 : * simply return a residue instead, so subtract off the
843 : * residue if drv->done() error processing indicates no
844 : * change to the completion length.
845 : */
846 0 : if (good_bytes == old_good_bytes)
847 0 : good_bytes -= scsi_get_resid(cmd);
848 : }
849 0 : scsi_io_completion(cmd, good_bytes);
850 0 : }
851 : EXPORT_SYMBOL(scsi_finish_command);
852 :
853 : /**
854 : * scsi_adjust_queue_depth - Let low level drivers change a device's queue depth
855 : * @sdev: SCSI Device in question
856 : * @tagged: Do we use tagged queueing (non-0) or do we treat
857 : * this device as an untagged device (0)
858 : * @tags: Number of tags allowed if tagged queueing enabled,
859 : * or number of commands the low level driver can
860 : * queue up in non-tagged mode (as per cmd_per_lun).
861 : *
862 : * Returns: Nothing
863 : *
864 : * Lock Status: None held on entry
865 : *
866 : * Notes: Low level drivers may call this at any time and we will do
867 : * the right thing depending on whether or not the device is
868 : * currently active and whether or not it even has the
869 : * command blocks built yet.
870 : */
871 : void scsi_adjust_queue_depth(struct scsi_device *sdev, int tagged, int tags)
872 : {
873 40 : unsigned long flags;
874 40 :
875 40 : /*
876 40 : * refuse to set tagged depth to an unworkable size
877 40 : */
878 120 : if (tags <= 0)
879 80 : return;
880 :
881 120 : spin_lock_irqsave(sdev->request_queue->queue_lock, flags);
882 :
883 : /*
884 : * Check to see if the queue is managed by the block layer.
885 : * If it is, and we fail to adjust the depth, exit.
886 : *
887 : * Do not resize the tag map if it is a host wide share bqt,
888 : * because the size should be the hosts's can_queue. If there
889 : * is more IO than the LLD's can_queue (so there are not enuogh
890 : * tags) request_fn's host queue ready check will handle it.
891 : */
892 120 : if (!sdev->host->bqt) {
893 280 : if (blk_queue_tagged(sdev->request_queue) &&
894 : blk_queue_resize_tags(sdev->request_queue, tags) != 0)
895 40 : goto out;
896 : }
897 :
898 80 : sdev->queue_depth = tags;
899 : switch (tagged) {
900 240 : case MSG_ORDERED_TAG:
901 80 : sdev->ordered_tags = 1;
902 80 : sdev->simple_tags = 1;
903 80 : break;
904 320 : case MSG_SIMPLE_TAG:
905 80 : sdev->ordered_tags = 0;
906 80 : sdev->simple_tags = 1;
907 80 : break;
908 160 : default:
909 320 : sdev_printk(KERN_WARNING, sdev,
910 : "scsi_adjust_queue_depth, bad queue type, "
911 : "disabled\n");
912 280 : case 0:
913 360 : sdev->ordered_tags = sdev->simple_tags = 0;
914 120 : sdev->queue_depth = tags;
915 120 : break;
916 : }
917 : out:
918 240 : spin_unlock_irqrestore(sdev->request_queue->queue_lock, flags);
919 160 : }
920 : EXPORT_SYMBOL(scsi_adjust_queue_depth);
921 :
922 : /**
923 : * scsi_track_queue_full - track QUEUE_FULL events to adjust queue depth
924 : * @sdev: SCSI Device in question
925 : * @depth: Current number of outstanding SCSI commands on this device,
926 : * not counting the one returned as QUEUE_FULL.
927 : *
928 : * Description: This function will track successive QUEUE_FULL events on a
929 : * specific SCSI device to determine if and when there is a
930 : * need to adjust the queue depth on the device.
931 : *
932 : * Returns: 0 - No change needed, >0 - Adjust queue depth to this new depth,
933 : * -1 - Drop back to untagged operation using host->cmd_per_lun
934 : * as the untagged command depth
935 : *
936 : * Lock Status: None held on entry
937 : *
938 : * Notes: Low level drivers may call this at any time and we will do
939 : * "The Right Thing." We are interrupt context safe.
940 : */
941 : int scsi_track_queue_full(struct scsi_device *sdev, int depth)
942 : {
943 :
944 : /*
945 : * Don't let QUEUE_FULLs on the same
946 : * jiffies count, they could all be from
947 : * same event.
948 : */
949 0 : if ((jiffies >> 4) == (sdev->last_queue_full_time >> 4))
950 0 : return 0;
951 :
952 0 : sdev->last_queue_full_time = jiffies;
953 0 : if (sdev->last_queue_full_depth != depth) {
954 0 : sdev->last_queue_full_count = 1;
955 0 : sdev->last_queue_full_depth = depth;
956 : } else {
957 0 : sdev->last_queue_full_count++;
958 : }
959 :
960 0 : if (sdev->last_queue_full_count <= 10)
961 0 : return 0;
962 0 : if (sdev->last_queue_full_depth < 8) {
963 : /* Drop back to untagged */
964 0 : scsi_adjust_queue_depth(sdev, 0, sdev->host->cmd_per_lun);
965 0 : return -1;
966 : }
967 :
968 0 : if (sdev->ordered_tags)
969 0 : scsi_adjust_queue_depth(sdev, MSG_ORDERED_TAG, depth);
970 : else
971 0 : scsi_adjust_queue_depth(sdev, MSG_SIMPLE_TAG, depth);
972 0 : return depth;
973 : }
974 : EXPORT_SYMBOL(scsi_track_queue_full);
975 :
976 : /**
977 : * scsi_vpd_inquiry - Request a device provide us with a VPD page
978 : * @sdev: The device to ask
979 : * @buffer: Where to put the result
980 : * @page: Which Vital Product Data to return
981 : * @len: The length of the buffer
982 : *
983 : * This is an internal helper function. You probably want to use
984 : * scsi_get_vpd_page instead.
985 : *
986 : * Returns 0 on success or a negative error number.
987 : */
988 : static int scsi_vpd_inquiry(struct scsi_device *sdev, unsigned char *buffer,
989 : u8 page, unsigned len)
990 : {
991 0 : int result;
992 0 : unsigned char cmd[16];
993 :
994 0 : cmd[0] = INQUIRY;
995 0 : cmd[1] = 1; /* EVPD */
996 0 : cmd[2] = page;
997 0 : cmd[3] = len >> 8;
998 0 : cmd[4] = len & 0xff;
999 0 : cmd[5] = 0; /* Control byte */
1000 :
1001 : /*
1002 : * I'm not convinced we need to try quite this hard to get VPD, but
1003 : * all the existing users tried this hard.
1004 : */
1005 0 : result = scsi_execute_req(sdev, cmd, DMA_FROM_DEVICE, buffer,
1006 : len, NULL, 30 * HZ, 3, NULL);
1007 0 : if (result)
1008 0 : return result;
1009 :
1010 : /* Sanity check that we got the page back that we asked for */
1011 0 : if (buffer[1] != page)
1012 0 : return -EIO;
1013 :
1014 0 : return 0;
1015 : }
1016 :
1017 : /**
1018 : * scsi_get_vpd_page - Get Vital Product Data from a SCSI device
1019 : * @sdev: The device to ask
1020 : * @page: Which Vital Product Data to return
1021 : *
1022 : * SCSI devices may optionally supply Vital Product Data. Each 'page'
1023 : * of VPD is defined in the appropriate SCSI document (eg SPC, SBC).
1024 : * If the device supports this VPD page, this routine returns a pointer
1025 : * to a buffer containing the data from that page. The caller is
1026 : * responsible for calling kfree() on this pointer when it is no longer
1027 : * needed. If we cannot retrieve the VPD page this routine returns %NULL.
1028 : */
1029 : unsigned char *scsi_get_vpd_page(struct scsi_device *sdev, u8 page)
1030 : {
1031 0 : int i, result;
1032 0 : unsigned int len;
1033 0 : const unsigned int init_vpd_len = 255;
1034 0 : unsigned char *buf = kmalloc(init_vpd_len, GFP_KERNEL);
1035 0 :
1036 0 : if (!buf)
1037 0 : return NULL;
1038 :
1039 : /* Ask for all the pages supported by this device */
1040 0 : result = scsi_vpd_inquiry(sdev, buf, 0, init_vpd_len);
1041 0 : if (result)
1042 0 : goto fail;
1043 :
1044 : /* If the user actually wanted this page, we can skip the rest */
1045 0 : if (page == 0)
1046 0 : return buf;
1047 :
1048 0 : for (i = 0; i < buf[3]; i++)
1049 0 : if (buf[i + 4] == page)
1050 0 : goto found;
1051 : /* The device claims it doesn't support the requested page */
1052 0 : goto fail;
1053 0 :
1054 : found:
1055 0 : result = scsi_vpd_inquiry(sdev, buf, page, 255);
1056 0 : if (result)
1057 0 : goto fail;
1058 :
1059 : /*
1060 : * Some pages are longer than 255 bytes. The actual length of
1061 : * the page is returned in the header.
1062 : */
1063 0 : len = ((buf[2] << 8) | buf[3]) + 4;
1064 0 : if (len <= init_vpd_len)
1065 0 : return buf;
1066 :
1067 0 : kfree(buf);
1068 0 : buf = kmalloc(len, GFP_KERNEL);
1069 0 : result = scsi_vpd_inquiry(sdev, buf, page, len);
1070 0 : if (result)
1071 0 : goto fail;
1072 :
1073 0 : return buf;
1074 0 :
1075 : fail:
1076 0 : kfree(buf);
1077 0 : return NULL;
1078 : }
1079 : EXPORT_SYMBOL_GPL(scsi_get_vpd_page);
1080 :
1081 : /**
1082 : * scsi_device_get - get an additional reference to a scsi_device
1083 : * @sdev: device to get a reference to
1084 : *
1085 : * Description: Gets a reference to the scsi_device and increments the use count
1086 : * of the underlying LLDD module. You must hold host_lock of the
1087 : * parent Scsi_Host or already have a reference when calling this.
1088 : */
1089 : int scsi_device_get(struct scsi_device *sdev)
1090 : {
1091 848 : if (sdev->sdev_state == SDEV_DEL)
1092 212 : return -ENXIO;
1093 636 : if (!get_device(&sdev->sdev_gendev))
1094 212 : return -ENXIO;
1095 : /* We can fail this if we're doing SCSI operations
1096 : * from module exit (like cache flush) */
1097 424 : try_module_get(sdev->host->hostt->module);
1098 :
1099 212 : return 0;
1100 : }
1101 : EXPORT_SYMBOL(scsi_device_get);
1102 :
1103 : /**
1104 : * scsi_device_put - release a reference to a scsi_device
1105 : * @sdev: device to release a reference on.
1106 : *
1107 : * Description: Release a reference to the scsi_device and decrements the use
1108 : * count of the underlying LLDD module. The device is freed once the last
1109 : * user vanishes.
1110 : */
1111 : void scsi_device_put(struct scsi_device *sdev)
1112 : {
1113 : #ifdef CONFIG_MODULE_UNLOAD
1114 : struct module *module = sdev->host->hostt->module;
1115 :
1116 : /* The module refcount will be zero if scsi_device_get()
1117 : * was called from a module removal routine */
1118 : if (module && module_refcount(module) != 0)
1119 : module_put(module);
1120 : #endif
1121 148 : put_device(&sdev->sdev_gendev);
1122 148 : }
1123 : EXPORT_SYMBOL(scsi_device_put);
1124 :
1125 : /* helper for shost_for_each_device, see that for documentation */
1126 : struct scsi_device *__scsi_iterate_devices(struct Scsi_Host *shost,
1127 : struct scsi_device *prev)
1128 0 : {
1129 0 : struct list_head *list = (prev ? &prev->siblings : &shost->__devices);
1130 0 : struct scsi_device *next = NULL;
1131 0 : unsigned long flags;
1132 0 :
1133 0 : spin_lock_irqsave(shost->host_lock, flags);
1134 0 : while (list->next != &shost->__devices) {
1135 0 : next = list_entry(list->next, struct scsi_device, siblings);
1136 0 : /* skip devices that we can't get a reference to */
1137 0 : if (!scsi_device_get(next))
1138 0 : break;
1139 0 : next = NULL;
1140 0 : list = list->next;
1141 0 : }
1142 0 : spin_unlock_irqrestore(shost->host_lock, flags);
1143 :
1144 0 : if (prev)
1145 0 : scsi_device_put(prev);
1146 0 : return next;
1147 : }
1148 : EXPORT_SYMBOL(__scsi_iterate_devices);
1149 :
1150 : /**
1151 : * starget_for_each_device - helper to walk all devices of a target
1152 : * @starget: target whose devices we want to iterate over.
1153 : * @data: Opaque passed to each function call.
1154 : * @fn: Function to call on each device
1155 : *
1156 : * This traverses over each device of @starget. The devices have
1157 : * a reference that must be released by scsi_host_put when breaking
1158 : * out of the loop.
1159 : */
1160 : void starget_for_each_device(struct scsi_target *starget, void *data,
1161 : void (*fn)(struct scsi_device *, void *))
1162 : {
1163 0 : struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
1164 0 : struct scsi_device *sdev;
1165 0 :
1166 0 : shost_for_each_device(sdev, shost) {
1167 0 : if ((sdev->channel == starget->channel) &&
1168 0 : (sdev->id == starget->id))
1169 0 : fn(sdev, data);
1170 : }
1171 : }
1172 : EXPORT_SYMBOL(starget_for_each_device);
1173 0 :
1174 : /**
1175 : * __starget_for_each_device - helper to walk all devices of a target (UNLOCKED)
1176 : * @starget: target whose devices we want to iterate over.
1177 : * @data: parameter for callback @fn()
1178 : * @fn: callback function that is invoked for each device
1179 : *
1180 : * This traverses over each device of @starget. It does _not_
1181 : * take a reference on the scsi_device, so the whole loop must be
1182 : * protected by shost->host_lock.
1183 : *
1184 : * Note: The only reason why drivers would want to use this is because
1185 : * they need to access the device list in irq context. Otherwise you
1186 : * really want to use starget_for_each_device instead.
1187 : **/
1188 : void __starget_for_each_device(struct scsi_target *starget, void *data,
1189 : void (*fn)(struct scsi_device *, void *))
1190 : {
1191 0 : struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
1192 0 : struct scsi_device *sdev;
1193 0 :
1194 0 : __shost_for_each_device(sdev, shost) {
1195 0 : if ((sdev->channel == starget->channel) &&
1196 0 : (sdev->id == starget->id))
1197 0 : fn(sdev, data);
1198 : }
1199 : }
1200 : EXPORT_SYMBOL(__starget_for_each_device);
1201 0 :
1202 : /**
1203 : * __scsi_device_lookup_by_target - find a device given the target (UNLOCKED)
1204 : * @starget: SCSI target pointer
1205 : * @lun: SCSI Logical Unit Number
1206 : *
1207 : * Description: Looks up the scsi_device with the specified @lun for a given
1208 : * @starget. The returned scsi_device does not have an additional
1209 : * reference. You must hold the host's host_lock over this call and
1210 : * any access to the returned scsi_device. A scsi_device in state
1211 : * SDEV_DEL is skipped.
1212 : *
1213 : * Note: The only reason why drivers should use this is because
1214 : * they need to access the device list in irq context. Otherwise you
1215 : * really want to use scsi_device_lookup_by_target instead.
1216 : **/
1217 : struct scsi_device *__scsi_device_lookup_by_target(struct scsi_target *starget,
1218 : uint lun)
1219 40 : {
1220 40 : struct scsi_device *sdev;
1221 40 :
1222 320 : list_for_each_entry(sdev, &starget->devices, same_target_siblings) {
1223 200 : if (sdev->sdev_state == SDEV_DEL)
1224 80 : continue;
1225 80 : if (sdev->lun ==lun)
1226 40 : return sdev;
1227 : }
1228 :
1229 40 : return NULL;
1230 40 : }
1231 : EXPORT_SYMBOL(__scsi_device_lookup_by_target);
1232 :
1233 : /**
1234 : * scsi_device_lookup_by_target - find a device given the target
1235 : * @starget: SCSI target pointer
1236 : * @lun: SCSI Logical Unit Number
1237 : *
1238 : * Description: Looks up the scsi_device with the specified @lun for a given
1239 : * @starget. The returned scsi_device has an additional reference that
1240 : * needs to be released with scsi_device_put once you're done with it.
1241 : **/
1242 : struct scsi_device *scsi_device_lookup_by_target(struct scsi_target *starget,
1243 : uint lun)
1244 40 : {
1245 40 : struct scsi_device *sdev;
1246 160 : struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
1247 40 : unsigned long flags;
1248 40 :
1249 160 : spin_lock_irqsave(shost->host_lock, flags);
1250 80 : sdev = __scsi_device_lookup_by_target(starget, lun);
1251 280 : if (sdev && scsi_device_get(sdev))
1252 40 : sdev = NULL;
1253 160 : spin_unlock_irqrestore(shost->host_lock, flags);
1254 :
1255 40 : return sdev;
1256 : }
1257 : EXPORT_SYMBOL(scsi_device_lookup_by_target);
1258 :
1259 : /**
1260 : * __scsi_device_lookup - find a device given the host (UNLOCKED)
1261 : * @shost: SCSI host pointer
1262 : * @channel: SCSI channel (zero if only one channel)
1263 : * @id: SCSI target number (physical unit number)
1264 : * @lun: SCSI Logical Unit Number
1265 : *
1266 : * Description: Looks up the scsi_device with the specified @channel, @id, @lun
1267 : * for a given host. The returned scsi_device does not have an additional
1268 : * reference. You must hold the host's host_lock over this call and any access
1269 : * to the returned scsi_device.
1270 : *
1271 : * Note: The only reason why drivers would want to use this is because
1272 : * they need to access the device list in irq context. Otherwise you
1273 : * really want to use scsi_device_lookup instead.
1274 : **/
1275 : struct scsi_device *__scsi_device_lookup(struct Scsi_Host *shost,
1276 : uint channel, uint id, uint lun)
1277 : {
1278 1 : struct scsi_device *sdev;
1279 1 :
1280 9 : list_for_each_entry(sdev, &shost->__devices, siblings) {
1281 8 : if (sdev->channel == channel && sdev->id == id &&
1282 1 : sdev->lun ==lun)
1283 1 : return sdev;
1284 : }
1285 :
1286 1 : return NULL;
1287 : }
1288 : EXPORT_SYMBOL(__scsi_device_lookup);
1289 :
1290 : /**
1291 : * scsi_device_lookup - find a device given the host
1292 : * @shost: SCSI host pointer
1293 : * @channel: SCSI channel (zero if only one channel)
1294 : * @id: SCSI target number (physical unit number)
1295 : * @lun: SCSI Logical Unit Number
1296 : *
1297 : * Description: Looks up the scsi_device with the specified @channel, @id, @lun
1298 : * for a given host. The returned scsi_device has an additional reference that
1299 : * needs to be released with scsi_device_put once you're done with it.
1300 : **/
1301 : struct scsi_device *scsi_device_lookup(struct Scsi_Host *shost,
1302 : uint channel, uint id, uint lun)
1303 : {
1304 1 : struct scsi_device *sdev;
1305 1 : unsigned long flags;
1306 1 :
1307 4 : spin_lock_irqsave(shost->host_lock, flags);
1308 2 : sdev = __scsi_device_lookup(shost, channel, id, lun);
1309 7 : if (sdev && scsi_device_get(sdev))
1310 1 : sdev = NULL;
1311 4 : spin_unlock_irqrestore(shost->host_lock, flags);
1312 :
1313 1 : return sdev;
1314 : }
1315 : EXPORT_SYMBOL(scsi_device_lookup);
1316 :
1317 : MODULE_DESCRIPTION("SCSI core");
1318 : MODULE_LICENSE("GPL");
1319 :
1320 : module_param(scsi_logging_level, int, S_IRUGO|S_IWUSR);
1321 : MODULE_PARM_DESC(scsi_logging_level, "a bit mask of logging levels");
1322 :
1323 : static int __init init_scsi(void)
1324 : {
1325 1 : int error;
1326 :
1327 4 : error = scsi_init_queue();
1328 2 : if (error)
1329 1 : return error;
1330 3 : error = scsi_init_procfs();
1331 2 : if (error)
1332 1 : goto cleanup_queue;
1333 6 : error = scsi_init_devinfo();
1334 2 : if (error)
1335 1 : goto cleanup_procfs;
1336 2 : error = scsi_init_hosts();
1337 2 : if (error)
1338 1 : goto cleanup_devlist;
1339 2 : error = scsi_init_sysctl();
1340 2 : if (error)
1341 1 : goto cleanup_hosts;
1342 2 : error = scsi_sysfs_register();
1343 2 : if (error)
1344 1 : goto cleanup_sysctl;
1345 :
1346 2 : scsi_netlink_init();
1347 :
1348 1 : printk(KERN_NOTICE "SCSI subsystem initialized\n");
1349 1 : return 0;
1350 1 :
1351 : cleanup_sysctl:
1352 2 : scsi_exit_sysctl();
1353 : cleanup_hosts:
1354 5 : scsi_exit_hosts();
1355 : cleanup_devlist:
1356 5 : scsi_exit_devinfo();
1357 : cleanup_procfs:
1358 5 : scsi_exit_procfs();
1359 : cleanup_queue:
1360 5 : scsi_exit_queue();
1361 1 : printk(KERN_ERR "SCSI subsystem failed to initialize, error = %d\n",
1362 : -error);
1363 1 : return error;
1364 : }
1365 :
1366 : static void __exit exit_scsi(void)
1367 : {
1368 4 : scsi_netlink_exit();
1369 4 : scsi_sysfs_unregister();
1370 4 : scsi_exit_sysctl();
1371 4 : scsi_exit_hosts();
1372 4 : scsi_exit_devinfo();
1373 4 : scsi_exit_procfs();
1374 4 : scsi_exit_queue();
1375 2 : }
1376 :
1377 : subsys_initcall(init_scsi);
1378 : module_exit(exit_scsi);
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