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#include <linux/async.h>
58#include <asm/unaligned.h>
59
60#include <scsi/scsi.h>
61#include <scsi/scsi_cmnd.h>
62#include <scsi/scsi_dbg.h>
63#include <scsi/scsi_device.h>
64#include <scsi/scsi_driver.h>
65#include <scsi/scsi_eh.h>
66#include <scsi/scsi_host.h>
67#include <scsi/scsi_tcq.h>
68
69#include "scsi_priv.h"
70#include "scsi_logging.h"
71
72#define CREATE_TRACE_POINTS
73#include <trace/events/scsi.h>
74
75/*
76 * Definitions and constants.
77 */
78
79/*
80 * Note - the initial logging level can be set here to log events at boot time.
81 * After the system is up, you may enable logging via the /proc interface.
82 */
83unsigned int scsi_logging_level;
84#if defined(CONFIG_SCSI_LOGGING)
85EXPORT_SYMBOL(scsi_logging_level);
86#endif
87
88/* sd, scsi core and power management need to coordinate flushing async actions */
89ASYNC_DOMAIN(scsi_sd_probe_domain);
90EXPORT_SYMBOL(scsi_sd_probe_domain);
91
92/*
93 * Separate domain (from scsi_sd_probe_domain) to maximize the benefit of
94 * asynchronous system resume operations. It is marked 'exclusive' to avoid
95 * being included in the async_synchronize_full() that is invoked by
96 * dpm_resume()
97 */
98ASYNC_DOMAIN_EXCLUSIVE(scsi_sd_pm_domain);
99EXPORT_SYMBOL(scsi_sd_pm_domain);
100
101/**
102 * scsi_put_command - Free a scsi command block
103 * @cmd: command block to free
104 *
105 * Returns: Nothing.
106 *
107 * Notes: The command must not belong to any lists.
108 */
109void scsi_put_command(struct scsi_cmnd *cmd)
110{
111 scsi_del_cmd_from_list(cmd);
112 BUG_ON(delayed_work_pending(&cmd->abort_work));
113}
114
115#ifdef CONFIG_SCSI_LOGGING
116void scsi_log_send(struct scsi_cmnd *cmd)
117{
118 unsigned int level;
119
120 /*
121 * If ML QUEUE log level is greater than or equal to:
122 *
123 * 1: nothing (match completion)
124 *
125 * 2: log opcode + command of all commands + cmd address
126 *
127 * 3: same as 2
128 *
129 * 4: same as 3
130 */
131 if (unlikely(scsi_logging_level)) {
132 level = SCSI_LOG_LEVEL(SCSI_LOG_MLQUEUE_SHIFT,
133 SCSI_LOG_MLQUEUE_BITS);
134 if (level > 1) {
135 scmd_printk(KERN_INFO, cmd,
136 "Send: scmd 0x%p\n", cmd);
137 scsi_print_command(cmd);
138 }
139 }
140}
141
142void scsi_log_completion(struct scsi_cmnd *cmd, int disposition)
143{
144 unsigned int level;
145
146 /*
147 * If ML COMPLETE log level is greater than or equal to:
148 *
149 * 1: log disposition, result, opcode + command, and conditionally
150 * sense data for failures or non SUCCESS dispositions.
151 *
152 * 2: same as 1 but for all command completions.
153 *
154 * 3: same as 2
155 *
156 * 4: same as 3 plus dump extra junk
157 */
158 if (unlikely(scsi_logging_level)) {
159 level = SCSI_LOG_LEVEL(SCSI_LOG_MLCOMPLETE_SHIFT,
160 SCSI_LOG_MLCOMPLETE_BITS);
161 if (((level > 0) && (cmd->result || disposition != SUCCESS)) ||
162 (level > 1)) {
163 scsi_print_result(cmd, "Done", disposition);
164 scsi_print_command(cmd);
165 if (status_byte(cmd->result) == CHECK_CONDITION)
166 scsi_print_sense(cmd);
167 if (level > 3)
168 scmd_printk(KERN_INFO, cmd,
169 "scsi host busy %d failed %d\n",
170 scsi_host_busy(cmd->device->host),
171 cmd->device->host->host_failed);
172 }
173 }
174}
175#endif
176
177/**
178 * scsi_finish_command - cleanup and pass command back to upper layer
179 * @cmd: the command
180 *
181 * Description: Pass command off to upper layer for finishing of I/O
182 * request, waking processes that are waiting on results,
183 * etc.
184 */
185void scsi_finish_command(struct scsi_cmnd *cmd)
186{
187 struct scsi_device *sdev = cmd->device;
188 struct scsi_target *starget = scsi_target(sdev);
189 struct Scsi_Host *shost = sdev->host;
190 struct scsi_driver *drv;
191 unsigned int good_bytes;
192
193 scsi_device_unbusy(sdev);
194
195 /*
196 * Clear the flags that say that the device/target/host is no longer
197 * capable of accepting new commands.
198 */
199 if (atomic_read(&shost->host_blocked))
200 atomic_set(&shost->host_blocked, 0);
201 if (atomic_read(&starget->target_blocked))
202 atomic_set(&starget->target_blocked, 0);
203 if (atomic_read(&sdev->device_blocked))
204 atomic_set(&sdev->device_blocked, 0);
205
206 /*
207 * If we have valid sense information, then some kind of recovery
208 * must have taken place. Make a note of this.
209 */
210 if (SCSI_SENSE_VALID(cmd))
211 cmd->result |= (DRIVER_SENSE << 24);
212
213 SCSI_LOG_MLCOMPLETE(4, sdev_printk(KERN_INFO, sdev,
214 "Notifying upper driver of completion "
215 "(result %x)\n", cmd->result));
216
217 good_bytes = scsi_bufflen(cmd);
218 if (!blk_rq_is_passthrough(cmd->request)) {
219 int old_good_bytes = good_bytes;
220 drv = scsi_cmd_to_driver(cmd);
221 if (drv->done)
222 good_bytes = drv->done(cmd);
223 /*
224 * USB may not give sense identifying bad sector and
225 * simply return a residue instead, so subtract off the
226 * residue if drv->done() error processing indicates no
227 * change to the completion length.
228 */
229 if (good_bytes == old_good_bytes)
230 good_bytes -= scsi_get_resid(cmd);
231 }
232 scsi_io_completion(cmd, good_bytes);
233}
234
235/**
236 * scsi_change_queue_depth - change a device's queue depth
237 * @sdev: SCSI Device in question
238 * @depth: number of commands allowed to be queued to the driver
239 *
240 * Sets the device queue depth and returns the new value.
241 */
242int scsi_change_queue_depth(struct scsi_device *sdev, int depth)
243{
244 if (depth > 0) {
245 sdev->queue_depth = depth;
246 wmb();
247 }
248
249 if (sdev->request_queue)
250 blk_set_queue_depth(sdev->request_queue, depth);
251
252 return sdev->queue_depth;
253}
254EXPORT_SYMBOL(scsi_change_queue_depth);
255
256/**
257 * scsi_track_queue_full - track QUEUE_FULL events to adjust queue depth
258 * @sdev: SCSI Device in question
259 * @depth: Current number of outstanding SCSI commands on this device,
260 * not counting the one returned as QUEUE_FULL.
261 *
262 * Description: This function will track successive QUEUE_FULL events on a
263 * specific SCSI device to determine if and when there is a
264 * need to adjust the queue depth on the device.
265 *
266 * Returns: 0 - No change needed, >0 - Adjust queue depth to this new depth,
267 * -1 - Drop back to untagged operation using host->cmd_per_lun
268 * as the untagged command depth
269 *
270 * Lock Status: None held on entry
271 *
272 * Notes: Low level drivers may call this at any time and we will do
273 * "The Right Thing." We are interrupt context safe.
274 */
275int scsi_track_queue_full(struct scsi_device *sdev, int depth)
276{
277
278 /*
279 * Don't let QUEUE_FULLs on the same
280 * jiffies count, they could all be from
281 * same event.
282 */
283 if ((jiffies >> 4) == (sdev->last_queue_full_time >> 4))
284 return 0;
285
286 sdev->last_queue_full_time = jiffies;
287 if (sdev->last_queue_full_depth != depth) {
288 sdev->last_queue_full_count = 1;
289 sdev->last_queue_full_depth = depth;
290 } else {
291 sdev->last_queue_full_count++;
292 }
293
294 if (sdev->last_queue_full_count <= 10)
295 return 0;
296
297 return scsi_change_queue_depth(sdev, depth);
298}
299EXPORT_SYMBOL(scsi_track_queue_full);
300
301/**
302 * scsi_vpd_inquiry - Request a device provide us with a VPD page
303 * @sdev: The device to ask
304 * @buffer: Where to put the result
305 * @page: Which Vital Product Data to return
306 * @len: The length of the buffer
307 *
308 * This is an internal helper function. You probably want to use
309 * scsi_get_vpd_page instead.
310 *
311 * Returns size of the vpd page on success or a negative error number.
312 */
313static int scsi_vpd_inquiry(struct scsi_device *sdev, unsigned char *buffer,
314 u8 page, unsigned len)
315{
316 int result;
317 unsigned char cmd[16];
318
319 if (len < 4)
320 return -EINVAL;
321
322 cmd[0] = INQUIRY;
323 cmd[1] = 1; /* EVPD */
324 cmd[2] = page;
325 cmd[3] = len >> 8;
326 cmd[4] = len & 0xff;
327 cmd[5] = 0; /* Control byte */
328
329 /*
330 * I'm not convinced we need to try quite this hard to get VPD, but
331 * all the existing users tried this hard.
332 */
333 result = scsi_execute_req(sdev, cmd, DMA_FROM_DEVICE, buffer,
334 len, NULL, 30 * HZ, 3, NULL);
335 if (result)
336 return -EIO;
337
338 /* Sanity check that we got the page back that we asked for */
339 if (buffer[1] != page)
340 return -EIO;
341
342 return get_unaligned_be16(&buffer[2]) + 4;
343}
344
345/**
346 * scsi_get_vpd_page - Get Vital Product Data from a SCSI device
347 * @sdev: The device to ask
348 * @page: Which Vital Product Data to return
349 * @buf: where to store the VPD
350 * @buf_len: number of bytes in the VPD buffer area
351 *
352 * SCSI devices may optionally supply Vital Product Data. Each 'page'
353 * of VPD is defined in the appropriate SCSI document (eg SPC, SBC).
354 * If the device supports this VPD page, this routine returns a pointer
355 * to a buffer containing the data from that page. The caller is
356 * responsible for calling kfree() on this pointer when it is no longer
357 * needed. If we cannot retrieve the VPD page this routine returns %NULL.
358 */
359int scsi_get_vpd_page(struct scsi_device *sdev, u8 page, unsigned char *buf,
360 int buf_len)
361{
362 int i, result;
363
364 if (sdev->skip_vpd_pages)
365 goto fail;
366
367 /* Ask for all the pages supported by this device */
368 result = scsi_vpd_inquiry(sdev, buf, 0, buf_len);
369 if (result < 4)
370 goto fail;
371
372 /* If the user actually wanted this page, we can skip the rest */
373 if (page == 0)
374 return 0;
375
376 for (i = 4; i < min(result, buf_len); i++)
377 if (buf[i] == page)
378 goto found;
379
380 if (i < result && i >= buf_len)
381 /* ran off the end of the buffer, give us benefit of doubt */
382 goto found;
383 /* The device claims it doesn't support the requested page */
384 goto fail;
385
386 found:
387 result = scsi_vpd_inquiry(sdev, buf, page, buf_len);
388 if (result < 0)
389 goto fail;
390
391 return 0;
392
393 fail:
394 return -EINVAL;
395}
396EXPORT_SYMBOL_GPL(scsi_get_vpd_page);
397
398/**
399 * scsi_get_vpd_buf - Get Vital Product Data from a SCSI device
400 * @sdev: The device to ask
401 * @page: Which Vital Product Data to return
402 *
403 * Returns %NULL upon failure.
404 */
405static struct scsi_vpd *scsi_get_vpd_buf(struct scsi_device *sdev, u8 page)
406{
407 struct scsi_vpd *vpd_buf;
408 int vpd_len = SCSI_VPD_PG_LEN, result;
409
410retry_pg:
411 vpd_buf = kmalloc(sizeof(*vpd_buf) + vpd_len, GFP_KERNEL);
412 if (!vpd_buf)
413 return NULL;
414
415 result = scsi_vpd_inquiry(sdev, vpd_buf->data, page, vpd_len);
416 if (result < 0) {
417 kfree(vpd_buf);
418 return NULL;
419 }
420 if (result > vpd_len) {
421 vpd_len = result;
422 kfree(vpd_buf);
423 goto retry_pg;
424 }
425
426 vpd_buf->len = result;
427
428 return vpd_buf;
429}
430
431static void scsi_update_vpd_page(struct scsi_device *sdev, u8 page,
432 struct scsi_vpd __rcu **sdev_vpd_buf)
433{
434 struct scsi_vpd *vpd_buf;
435
436 vpd_buf = scsi_get_vpd_buf(sdev, page);
437 if (!vpd_buf)
438 return;
439
440 mutex_lock(&sdev->inquiry_mutex);
441 rcu_swap_protected(*sdev_vpd_buf, vpd_buf,
442 lockdep_is_held(&sdev->inquiry_mutex));
443 mutex_unlock(&sdev->inquiry_mutex);
444
445 if (vpd_buf)
446 kfree_rcu(vpd_buf, rcu);
447}
448
449/**
450 * scsi_attach_vpd - Attach Vital Product Data to a SCSI device structure
451 * @sdev: The device to ask
452 *
453 * Attach the 'Device Identification' VPD page (0x83) and the
454 * 'Unit Serial Number' VPD page (0x80) to a SCSI device
455 * structure. This information can be used to identify the device
456 * uniquely.
457 */
458void scsi_attach_vpd(struct scsi_device *sdev)
459{
460 int i;
461 struct scsi_vpd *vpd_buf;
462
463 if (!scsi_device_supports_vpd(sdev))
464 return;
465
466 /* Ask for all the pages supported by this device */
467 vpd_buf = scsi_get_vpd_buf(sdev, 0);
468 if (!vpd_buf)
469 return;
470
471 for (i = 4; i < vpd_buf->len; i++) {
472 if (vpd_buf->data[i] == 0x80)
473 scsi_update_vpd_page(sdev, 0x80, &sdev->vpd_pg80);
474 if (vpd_buf->data[i] == 0x83)
475 scsi_update_vpd_page(sdev, 0x83, &sdev->vpd_pg83);
476 }
477 kfree(vpd_buf);
478}
479
480/**
481 * scsi_report_opcode - Find out if a given command opcode is supported
482 * @sdev: scsi device to query
483 * @buffer: scratch buffer (must be at least 20 bytes long)
484 * @len: length of buffer
485 * @opcode: opcode for command to look up
486 *
487 * Uses the REPORT SUPPORTED OPERATION CODES to look up the given
488 * opcode. Returns -EINVAL if RSOC fails, 0 if the command opcode is
489 * unsupported and 1 if the device claims to support the command.
490 */
491int scsi_report_opcode(struct scsi_device *sdev, unsigned char *buffer,
492 unsigned int len, unsigned char opcode)
493{
494 unsigned char cmd[16];
495 struct scsi_sense_hdr sshdr;
496 int result;
497
498 if (sdev->no_report_opcodes || sdev->scsi_level < SCSI_SPC_3)
499 return -EINVAL;
500
501 memset(cmd, 0, 16);
502 cmd[0] = MAINTENANCE_IN;
503 cmd[1] = MI_REPORT_SUPPORTED_OPERATION_CODES;
504 cmd[2] = 1; /* One command format */
505 cmd[3] = opcode;
506 put_unaligned_be32(len, &cmd[6]);
507 memset(buffer, 0, len);
508
509 result = scsi_execute_req(sdev, cmd, DMA_FROM_DEVICE, buffer, len,
510 &sshdr, 30 * HZ, 3, NULL);
511
512 if (result && scsi_sense_valid(&sshdr) &&
513 sshdr.sense_key == ILLEGAL_REQUEST &&
514 (sshdr.asc == 0x20 || sshdr.asc == 0x24) && sshdr.ascq == 0x00)
515 return -EINVAL;
516
517 if ((buffer[1] & 3) == 3) /* Command supported */
518 return 1;
519
520 return 0;
521}
522EXPORT_SYMBOL(scsi_report_opcode);
523
524/**
525 * scsi_device_get - get an additional reference to a scsi_device
526 * @sdev: device to get a reference to
527 *
528 * Description: Gets a reference to the scsi_device and increments the use count
529 * of the underlying LLDD module. You must hold host_lock of the
530 * parent Scsi_Host or already have a reference when calling this.
531 *
532 * This will fail if a device is deleted or cancelled, or when the LLD module
533 * is in the process of being unloaded.
534 */
535int scsi_device_get(struct scsi_device *sdev)
536{
537 if (sdev->sdev_state == SDEV_DEL || sdev->sdev_state == SDEV_CANCEL)
538 goto fail;
539 if (!get_device(&sdev->sdev_gendev))
540 goto fail;
541 if (!try_module_get(sdev->host->hostt->module))
542 goto fail_put_device;
543 return 0;
544
545fail_put_device:
546 put_device(&sdev->sdev_gendev);
547fail:
548 return -ENXIO;
549}
550EXPORT_SYMBOL(scsi_device_get);
551
552/**
553 * scsi_device_put - release a reference to a scsi_device
554 * @sdev: device to release a reference on.
555 *
556 * Description: Release a reference to the scsi_device and decrements the use
557 * count of the underlying LLDD module. The device is freed once the last
558 * user vanishes.
559 */
560void scsi_device_put(struct scsi_device *sdev)
561{
562 module_put(sdev->host->hostt->module);
563 put_device(&sdev->sdev_gendev);
564}
565EXPORT_SYMBOL(scsi_device_put);
566
567/* helper for shost_for_each_device, see that for documentation */
568struct scsi_device *__scsi_iterate_devices(struct Scsi_Host *shost,
569 struct scsi_device *prev)
570{
571 struct list_head *list = (prev ? &prev->siblings : &shost->__devices);
572 struct scsi_device *next = NULL;
573 unsigned long flags;
574
575 spin_lock_irqsave(shost->host_lock, flags);
576 while (list->next != &shost->__devices) {
577 next = list_entry(list->next, struct scsi_device, siblings);
578 /* skip devices that we can't get a reference to */
579 if (!scsi_device_get(next))
580 break;
581 next = NULL;
582 list = list->next;
583 }
584 spin_unlock_irqrestore(shost->host_lock, flags);
585
586 if (prev)
587 scsi_device_put(prev);
588 return next;
589}
590EXPORT_SYMBOL(__scsi_iterate_devices);
591
592/**
593 * starget_for_each_device - helper to walk all devices of a target
594 * @starget: target whose devices we want to iterate over.
595 * @data: Opaque passed to each function call.
596 * @fn: Function to call on each device
597 *
598 * This traverses over each device of @starget. The devices have
599 * a reference that must be released by scsi_host_put when breaking
600 * out of the loop.
601 */
602void starget_for_each_device(struct scsi_target *starget, void *data,
603 void (*fn)(struct scsi_device *, void *))
604{
605 struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
606 struct scsi_device *sdev;
607
608 shost_for_each_device(sdev, shost) {
609 if ((sdev->channel == starget->channel) &&
610 (sdev->id == starget->id))
611 fn(sdev, data);
612 }
613}
614EXPORT_SYMBOL(starget_for_each_device);
615
616/**
617 * __starget_for_each_device - helper to walk all devices of a target (UNLOCKED)
618 * @starget: target whose devices we want to iterate over.
619 * @data: parameter for callback @fn()
620 * @fn: callback function that is invoked for each device
621 *
622 * This traverses over each device of @starget. It does _not_
623 * take a reference on the scsi_device, so the whole loop must be
624 * protected by shost->host_lock.
625 *
626 * Note: The only reason why drivers would want to use this is because
627 * they need to access the device list in irq context. Otherwise you
628 * really want to use starget_for_each_device instead.
629 **/
630void __starget_for_each_device(struct scsi_target *starget, void *data,
631 void (*fn)(struct scsi_device *, void *))
632{
633 struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
634 struct scsi_device *sdev;
635
636 __shost_for_each_device(sdev, shost) {
637 if ((sdev->channel == starget->channel) &&
638 (sdev->id == starget->id))
639 fn(sdev, data);
640 }
641}
642EXPORT_SYMBOL(__starget_for_each_device);
643
644/**
645 * __scsi_device_lookup_by_target - find a device given the target (UNLOCKED)
646 * @starget: SCSI target pointer
647 * @lun: SCSI Logical Unit Number
648 *
649 * Description: Looks up the scsi_device with the specified @lun for a given
650 * @starget. The returned scsi_device does not have an additional
651 * reference. You must hold the host's host_lock over this call and
652 * any access to the returned scsi_device. A scsi_device in state
653 * SDEV_DEL is skipped.
654 *
655 * Note: The only reason why drivers should use this is because
656 * they need to access the device list in irq context. Otherwise you
657 * really want to use scsi_device_lookup_by_target instead.
658 **/
659struct scsi_device *__scsi_device_lookup_by_target(struct scsi_target *starget,
660 u64 lun)
661{
662 struct scsi_device *sdev;
663
664 list_for_each_entry(sdev, &starget->devices, same_target_siblings) {
665 if (sdev->sdev_state == SDEV_DEL)
666 continue;
667 if (sdev->lun ==lun)
668 return sdev;
669 }
670
671 return NULL;
672}
673EXPORT_SYMBOL(__scsi_device_lookup_by_target);
674
675/**
676 * scsi_device_lookup_by_target - find a device given the target
677 * @starget: SCSI target pointer
678 * @lun: SCSI Logical Unit Number
679 *
680 * Description: Looks up the scsi_device with the specified @lun for a given
681 * @starget. The returned scsi_device has an additional reference that
682 * needs to be released with scsi_device_put once you're done with it.
683 **/
684struct scsi_device *scsi_device_lookup_by_target(struct scsi_target *starget,
685 u64 lun)
686{
687 struct scsi_device *sdev;
688 struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
689 unsigned long flags;
690
691 spin_lock_irqsave(shost->host_lock, flags);
692 sdev = __scsi_device_lookup_by_target(starget, lun);
693 if (sdev && scsi_device_get(sdev))
694 sdev = NULL;
695 spin_unlock_irqrestore(shost->host_lock, flags);
696
697 return sdev;
698}
699EXPORT_SYMBOL(scsi_device_lookup_by_target);
700
701/**
702 * __scsi_device_lookup - find a device given the host (UNLOCKED)
703 * @shost: SCSI host pointer
704 * @channel: SCSI channel (zero if only one channel)
705 * @id: SCSI target number (physical unit number)
706 * @lun: SCSI Logical Unit Number
707 *
708 * Description: Looks up the scsi_device with the specified @channel, @id, @lun
709 * for a given host. The returned scsi_device does not have an additional
710 * reference. You must hold the host's host_lock over this call and any access
711 * to the returned scsi_device.
712 *
713 * Note: The only reason why drivers would want to use this is because
714 * they need to access the device list in irq context. Otherwise you
715 * really want to use scsi_device_lookup instead.
716 **/
717struct scsi_device *__scsi_device_lookup(struct Scsi_Host *shost,
718 uint channel, uint id, u64 lun)
719{
720 struct scsi_device *sdev;
721
722 list_for_each_entry(sdev, &shost->__devices, siblings) {
723 if (sdev->sdev_state == SDEV_DEL)
724 continue;
725 if (sdev->channel == channel && sdev->id == id &&
726 sdev->lun ==lun)
727 return sdev;
728 }
729
730 return NULL;
731}
732EXPORT_SYMBOL(__scsi_device_lookup);
733
734/**
735 * scsi_device_lookup - find a device given the host
736 * @shost: SCSI host pointer
737 * @channel: SCSI channel (zero if only one channel)
738 * @id: SCSI target number (physical unit number)
739 * @lun: SCSI Logical Unit Number
740 *
741 * Description: Looks up the scsi_device with the specified @channel, @id, @lun
742 * for a given host. The returned scsi_device has an additional reference that
743 * needs to be released with scsi_device_put once you're done with it.
744 **/
745struct scsi_device *scsi_device_lookup(struct Scsi_Host *shost,
746 uint channel, uint id, u64 lun)
747{
748 struct scsi_device *sdev;
749 unsigned long flags;
750
751 spin_lock_irqsave(shost->host_lock, flags);
752 sdev = __scsi_device_lookup(shost, channel, id, lun);
753 if (sdev && scsi_device_get(sdev))
754 sdev = NULL;
755 spin_unlock_irqrestore(shost->host_lock, flags);
756
757 return sdev;
758}
759EXPORT_SYMBOL(scsi_device_lookup);
760
761MODULE_DESCRIPTION("SCSI core");
762MODULE_LICENSE("GPL");
763
764module_param(scsi_logging_level, int, S_IRUGO|S_IWUSR);
765MODULE_PARM_DESC(scsi_logging_level, "a bit mask of logging levels");
766
767/* This should go away in the future, it doesn't do anything anymore */
768bool scsi_use_blk_mq = true;
769module_param_named(use_blk_mq, scsi_use_blk_mq, bool, S_IWUSR | S_IRUGO);
770
771static int __init init_scsi(void)
772{
773 int error;
774
775 error = scsi_init_queue();
776 if (error)
777 return error;
778 error = scsi_init_procfs();
779 if (error)
780 goto cleanup_queue;
781 error = scsi_init_devinfo();
782 if (error)
783 goto cleanup_procfs;
784 error = scsi_init_hosts();
785 if (error)
786 goto cleanup_devlist;
787 error = scsi_init_sysctl();
788 if (error)
789 goto cleanup_hosts;
790 error = scsi_sysfs_register();
791 if (error)
792 goto cleanup_sysctl;
793
794 scsi_netlink_init();
795
796 printk(KERN_NOTICE "SCSI subsystem initialized\n");
797 return 0;
798
799cleanup_sysctl:
800 scsi_exit_sysctl();
801cleanup_hosts:
802 scsi_exit_hosts();
803cleanup_devlist:
804 scsi_exit_devinfo();
805cleanup_procfs:
806 scsi_exit_procfs();
807cleanup_queue:
808 scsi_exit_queue();
809 printk(KERN_ERR "SCSI subsystem failed to initialize, error = %d\n",
810 -error);
811 return error;
812}
813
814static void __exit exit_scsi(void)
815{
816 scsi_netlink_exit();
817 scsi_sysfs_unregister();
818 scsi_exit_sysctl();
819 scsi_exit_hosts();
820 scsi_exit_devinfo();
821 scsi_exit_procfs();
822 scsi_exit_queue();
823 async_unregister_domain(&scsi_sd_probe_domain);
824}
825
826subsys_initcall(init_scsi);
827module_exit(exit_scsi);
828