Loading...
1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * scsi.c Copyright (C) 1992 Drew Eckhardt
4 * Copyright (C) 1993, 1994, 1995, 1999 Eric Youngdale
5 * Copyright (C) 2002, 2003 Christoph Hellwig
6 *
7 * generic mid-level SCSI driver
8 * Initial versions: Drew Eckhardt
9 * Subsequent revisions: Eric Youngdale
10 *
11 * <drew@colorado.edu>
12 *
13 * Bug correction thanks go to :
14 * Rik Faith <faith@cs.unc.edu>
15 * Tommy Thorn <tthorn>
16 * Thomas Wuensche <tw@fgb1.fgb.mw.tu-muenchen.de>
17 *
18 * Modified by Eric Youngdale eric@andante.org or ericy@gnu.ai.mit.edu to
19 * add scatter-gather, multiple outstanding request, and other
20 * enhancements.
21 *
22 * Native multichannel, wide scsi, /proc/scsi and hot plugging
23 * support added by Michael Neuffer <mike@i-connect.net>
24 *
25 * Added request_module("scsi_hostadapter") for kerneld:
26 * (Put an "alias scsi_hostadapter your_hostadapter" in /etc/modprobe.conf)
27 * Bjorn Ekwall <bj0rn@blox.se>
28 * (changed to kmod)
29 *
30 * Major improvements to the timeout, abort, and reset processing,
31 * as well as performance modifications for large queue depths by
32 * Leonard N. Zubkoff <lnz@dandelion.com>
33 *
34 * Converted cli() code to spinlocks, Ingo Molnar
35 *
36 * Jiffies wrap fixes (host->resetting), 3 Dec 1998 Andrea Arcangeli
37 *
38 * out_of_space hacks, D. Gilbert (dpg) 990608
39 */
40
41#include <linux/module.h>
42#include <linux/moduleparam.h>
43#include <linux/kernel.h>
44#include <linux/timer.h>
45#include <linux/string.h>
46#include <linux/slab.h>
47#include <linux/blkdev.h>
48#include <linux/delay.h>
49#include <linux/init.h>
50#include <linux/completion.h>
51#include <linux/unistd.h>
52#include <linux/spinlock.h>
53#include <linux/kmod.h>
54#include <linux/interrupt.h>
55#include <linux/notifier.h>
56#include <linux/cpu.h>
57#include <linux/mutex.h>
58#include <linux/async.h>
59#include <asm/unaligned.h>
60
61#include <scsi/scsi.h>
62#include <scsi/scsi_cmnd.h>
63#include <scsi/scsi_dbg.h>
64#include <scsi/scsi_device.h>
65#include <scsi/scsi_driver.h>
66#include <scsi/scsi_eh.h>
67#include <scsi/scsi_host.h>
68#include <scsi/scsi_tcq.h>
69
70#include "scsi_priv.h"
71#include "scsi_logging.h"
72
73#define CREATE_TRACE_POINTS
74#include <trace/events/scsi.h>
75
76/*
77 * Definitions and constants.
78 */
79
80/*
81 * Note - the initial logging level can be set here to log events at boot time.
82 * After the system is up, you may enable logging via the /proc interface.
83 */
84unsigned int scsi_logging_level;
85#if defined(CONFIG_SCSI_LOGGING)
86EXPORT_SYMBOL(scsi_logging_level);
87#endif
88
89/*
90 * Domain for asynchronous system resume operations. It is marked 'exclusive'
91 * to avoid being included in the async_synchronize_full() that is invoked by
92 * dpm_resume().
93 */
94ASYNC_DOMAIN_EXCLUSIVE(scsi_sd_pm_domain);
95EXPORT_SYMBOL(scsi_sd_pm_domain);
96
97#ifdef CONFIG_SCSI_LOGGING
98void scsi_log_send(struct scsi_cmnd *cmd)
99{
100 unsigned int level;
101
102 /*
103 * If ML QUEUE log level is greater than or equal to:
104 *
105 * 1: nothing (match completion)
106 *
107 * 2: log opcode + command of all commands + cmd address
108 *
109 * 3: same as 2
110 *
111 * 4: same as 3
112 */
113 if (unlikely(scsi_logging_level)) {
114 level = SCSI_LOG_LEVEL(SCSI_LOG_MLQUEUE_SHIFT,
115 SCSI_LOG_MLQUEUE_BITS);
116 if (level > 1) {
117 scmd_printk(KERN_INFO, cmd,
118 "Send: scmd 0x%p\n", cmd);
119 scsi_print_command(cmd);
120 }
121 }
122}
123
124void scsi_log_completion(struct scsi_cmnd *cmd, int disposition)
125{
126 unsigned int level;
127
128 /*
129 * If ML COMPLETE log level is greater than or equal to:
130 *
131 * 1: log disposition, result, opcode + command, and conditionally
132 * sense data for failures or non SUCCESS dispositions.
133 *
134 * 2: same as 1 but for all command completions.
135 *
136 * 3: same as 2
137 *
138 * 4: same as 3 plus dump extra junk
139 */
140 if (unlikely(scsi_logging_level)) {
141 level = SCSI_LOG_LEVEL(SCSI_LOG_MLCOMPLETE_SHIFT,
142 SCSI_LOG_MLCOMPLETE_BITS);
143 if (((level > 0) && (cmd->result || disposition != SUCCESS)) ||
144 (level > 1)) {
145 scsi_print_result(cmd, "Done", disposition);
146 scsi_print_command(cmd);
147 if (scsi_status_is_check_condition(cmd->result))
148 scsi_print_sense(cmd);
149 if (level > 3)
150 scmd_printk(KERN_INFO, cmd,
151 "scsi host busy %d failed %d\n",
152 scsi_host_busy(cmd->device->host),
153 cmd->device->host->host_failed);
154 }
155 }
156}
157#endif
158
159/**
160 * scsi_finish_command - cleanup and pass command back to upper layer
161 * @cmd: the command
162 *
163 * Description: Pass command off to upper layer for finishing of I/O
164 * request, waking processes that are waiting on results,
165 * etc.
166 */
167void scsi_finish_command(struct scsi_cmnd *cmd)
168{
169 struct scsi_device *sdev = cmd->device;
170 struct scsi_target *starget = scsi_target(sdev);
171 struct Scsi_Host *shost = sdev->host;
172 struct scsi_driver *drv;
173 unsigned int good_bytes;
174
175 scsi_device_unbusy(sdev, cmd);
176
177 /*
178 * Clear the flags that say that the device/target/host is no longer
179 * capable of accepting new commands.
180 */
181 if (atomic_read(&shost->host_blocked))
182 atomic_set(&shost->host_blocked, 0);
183 if (atomic_read(&starget->target_blocked))
184 atomic_set(&starget->target_blocked, 0);
185 if (atomic_read(&sdev->device_blocked))
186 atomic_set(&sdev->device_blocked, 0);
187
188 SCSI_LOG_MLCOMPLETE(4, sdev_printk(KERN_INFO, sdev,
189 "Notifying upper driver of completion "
190 "(result %x)\n", cmd->result));
191
192 good_bytes = scsi_bufflen(cmd);
193 if (!blk_rq_is_passthrough(cmd->request)) {
194 int old_good_bytes = good_bytes;
195 drv = scsi_cmd_to_driver(cmd);
196 if (drv->done)
197 good_bytes = drv->done(cmd);
198 /*
199 * USB may not give sense identifying bad sector and
200 * simply return a residue instead, so subtract off the
201 * residue if drv->done() error processing indicates no
202 * change to the completion length.
203 */
204 if (good_bytes == old_good_bytes)
205 good_bytes -= scsi_get_resid(cmd);
206 }
207 scsi_io_completion(cmd, good_bytes);
208}
209
210
211/*
212 * 1024 is big enough for saturating the fast scsi LUN now
213 */
214int scsi_device_max_queue_depth(struct scsi_device *sdev)
215{
216 return max_t(int, sdev->host->can_queue, 1024);
217}
218
219/**
220 * scsi_change_queue_depth - change a device's queue depth
221 * @sdev: SCSI Device in question
222 * @depth: number of commands allowed to be queued to the driver
223 *
224 * Sets the device queue depth and returns the new value.
225 */
226int scsi_change_queue_depth(struct scsi_device *sdev, int depth)
227{
228 depth = min_t(int, depth, scsi_device_max_queue_depth(sdev));
229
230 if (depth > 0) {
231 sdev->queue_depth = depth;
232 wmb();
233 }
234
235 if (sdev->request_queue)
236 blk_set_queue_depth(sdev->request_queue, depth);
237
238 sbitmap_resize(&sdev->budget_map, sdev->queue_depth);
239
240 return sdev->queue_depth;
241}
242EXPORT_SYMBOL(scsi_change_queue_depth);
243
244/**
245 * scsi_track_queue_full - track QUEUE_FULL events to adjust queue depth
246 * @sdev: SCSI Device in question
247 * @depth: Current number of outstanding SCSI commands on this device,
248 * not counting the one returned as QUEUE_FULL.
249 *
250 * Description: This function will track successive QUEUE_FULL events on a
251 * specific SCSI device to determine if and when there is a
252 * need to adjust the queue depth on the device.
253 *
254 * Returns: 0 - No change needed, >0 - Adjust queue depth to this new depth,
255 * -1 - Drop back to untagged operation using host->cmd_per_lun
256 * as the untagged command depth
257 *
258 * Lock Status: None held on entry
259 *
260 * Notes: Low level drivers may call this at any time and we will do
261 * "The Right Thing." We are interrupt context safe.
262 */
263int scsi_track_queue_full(struct scsi_device *sdev, int depth)
264{
265
266 /*
267 * Don't let QUEUE_FULLs on the same
268 * jiffies count, they could all be from
269 * same event.
270 */
271 if ((jiffies >> 4) == (sdev->last_queue_full_time >> 4))
272 return 0;
273
274 sdev->last_queue_full_time = jiffies;
275 if (sdev->last_queue_full_depth != depth) {
276 sdev->last_queue_full_count = 1;
277 sdev->last_queue_full_depth = depth;
278 } else {
279 sdev->last_queue_full_count++;
280 }
281
282 if (sdev->last_queue_full_count <= 10)
283 return 0;
284
285 return scsi_change_queue_depth(sdev, depth);
286}
287EXPORT_SYMBOL(scsi_track_queue_full);
288
289/**
290 * scsi_vpd_inquiry - Request a device provide us with a VPD page
291 * @sdev: The device to ask
292 * @buffer: Where to put the result
293 * @page: Which Vital Product Data to return
294 * @len: The length of the buffer
295 *
296 * This is an internal helper function. You probably want to use
297 * scsi_get_vpd_page instead.
298 *
299 * Returns size of the vpd page on success or a negative error number.
300 */
301static int scsi_vpd_inquiry(struct scsi_device *sdev, unsigned char *buffer,
302 u8 page, unsigned len)
303{
304 int result;
305 unsigned char cmd[16];
306
307 if (len < 4)
308 return -EINVAL;
309
310 cmd[0] = INQUIRY;
311 cmd[1] = 1; /* EVPD */
312 cmd[2] = page;
313 cmd[3] = len >> 8;
314 cmd[4] = len & 0xff;
315 cmd[5] = 0; /* Control byte */
316
317 /*
318 * I'm not convinced we need to try quite this hard to get VPD, but
319 * all the existing users tried this hard.
320 */
321 result = scsi_execute_req(sdev, cmd, DMA_FROM_DEVICE, buffer,
322 len, NULL, 30 * HZ, 3, NULL);
323 if (result)
324 return -EIO;
325
326 /* Sanity check that we got the page back that we asked for */
327 if (buffer[1] != page)
328 return -EIO;
329
330 return get_unaligned_be16(&buffer[2]) + 4;
331}
332
333/**
334 * scsi_get_vpd_page - Get Vital Product Data from a SCSI device
335 * @sdev: The device to ask
336 * @page: Which Vital Product Data to return
337 * @buf: where to store the VPD
338 * @buf_len: number of bytes in the VPD buffer area
339 *
340 * SCSI devices may optionally supply Vital Product Data. Each 'page'
341 * of VPD is defined in the appropriate SCSI document (eg SPC, SBC).
342 * If the device supports this VPD page, this routine returns a pointer
343 * to a buffer containing the data from that page. The caller is
344 * responsible for calling kfree() on this pointer when it is no longer
345 * needed. If we cannot retrieve the VPD page this routine returns %NULL.
346 */
347int scsi_get_vpd_page(struct scsi_device *sdev, u8 page, unsigned char *buf,
348 int buf_len)
349{
350 int i, result;
351
352 if (sdev->skip_vpd_pages)
353 goto fail;
354
355 /* Ask for all the pages supported by this device */
356 result = scsi_vpd_inquiry(sdev, buf, 0, buf_len);
357 if (result < 4)
358 goto fail;
359
360 /* If the user actually wanted this page, we can skip the rest */
361 if (page == 0)
362 return 0;
363
364 for (i = 4; i < min(result, buf_len); i++)
365 if (buf[i] == page)
366 goto found;
367
368 if (i < result && i >= buf_len)
369 /* ran off the end of the buffer, give us benefit of doubt */
370 goto found;
371 /* The device claims it doesn't support the requested page */
372 goto fail;
373
374 found:
375 result = scsi_vpd_inquiry(sdev, buf, page, buf_len);
376 if (result < 0)
377 goto fail;
378
379 return 0;
380
381 fail:
382 return -EINVAL;
383}
384EXPORT_SYMBOL_GPL(scsi_get_vpd_page);
385
386/**
387 * scsi_get_vpd_buf - Get Vital Product Data from a SCSI device
388 * @sdev: The device to ask
389 * @page: Which Vital Product Data to return
390 *
391 * Returns %NULL upon failure.
392 */
393static struct scsi_vpd *scsi_get_vpd_buf(struct scsi_device *sdev, u8 page)
394{
395 struct scsi_vpd *vpd_buf;
396 int vpd_len = SCSI_VPD_PG_LEN, result;
397
398retry_pg:
399 vpd_buf = kmalloc(sizeof(*vpd_buf) + vpd_len, GFP_KERNEL);
400 if (!vpd_buf)
401 return NULL;
402
403 result = scsi_vpd_inquiry(sdev, vpd_buf->data, page, vpd_len);
404 if (result < 0) {
405 kfree(vpd_buf);
406 return NULL;
407 }
408 if (result > vpd_len) {
409 vpd_len = result;
410 kfree(vpd_buf);
411 goto retry_pg;
412 }
413
414 vpd_buf->len = result;
415
416 return vpd_buf;
417}
418
419static void scsi_update_vpd_page(struct scsi_device *sdev, u8 page,
420 struct scsi_vpd __rcu **sdev_vpd_buf)
421{
422 struct scsi_vpd *vpd_buf;
423
424 vpd_buf = scsi_get_vpd_buf(sdev, page);
425 if (!vpd_buf)
426 return;
427
428 mutex_lock(&sdev->inquiry_mutex);
429 vpd_buf = rcu_replace_pointer(*sdev_vpd_buf, vpd_buf,
430 lockdep_is_held(&sdev->inquiry_mutex));
431 mutex_unlock(&sdev->inquiry_mutex);
432
433 if (vpd_buf)
434 kfree_rcu(vpd_buf, rcu);
435}
436
437/**
438 * scsi_attach_vpd - Attach Vital Product Data to a SCSI device structure
439 * @sdev: The device to ask
440 *
441 * Attach the 'Device Identification' VPD page (0x83) and the
442 * 'Unit Serial Number' VPD page (0x80) to a SCSI device
443 * structure. This information can be used to identify the device
444 * uniquely.
445 */
446void scsi_attach_vpd(struct scsi_device *sdev)
447{
448 int i;
449 struct scsi_vpd *vpd_buf;
450
451 if (!scsi_device_supports_vpd(sdev))
452 return;
453
454 /* Ask for all the pages supported by this device */
455 vpd_buf = scsi_get_vpd_buf(sdev, 0);
456 if (!vpd_buf)
457 return;
458
459 for (i = 4; i < vpd_buf->len; i++) {
460 if (vpd_buf->data[i] == 0x0)
461 scsi_update_vpd_page(sdev, 0x0, &sdev->vpd_pg0);
462 if (vpd_buf->data[i] == 0x80)
463 scsi_update_vpd_page(sdev, 0x80, &sdev->vpd_pg80);
464 if (vpd_buf->data[i] == 0x83)
465 scsi_update_vpd_page(sdev, 0x83, &sdev->vpd_pg83);
466 if (vpd_buf->data[i] == 0x89)
467 scsi_update_vpd_page(sdev, 0x89, &sdev->vpd_pg89);
468 }
469 kfree(vpd_buf);
470}
471
472/**
473 * scsi_report_opcode - Find out if a given command opcode is supported
474 * @sdev: scsi device to query
475 * @buffer: scratch buffer (must be at least 20 bytes long)
476 * @len: length of buffer
477 * @opcode: opcode for command to look up
478 *
479 * Uses the REPORT SUPPORTED OPERATION CODES to look up the given
480 * opcode. Returns -EINVAL if RSOC fails, 0 if the command opcode is
481 * unsupported and 1 if the device claims to support the command.
482 */
483int scsi_report_opcode(struct scsi_device *sdev, unsigned char *buffer,
484 unsigned int len, unsigned char opcode)
485{
486 unsigned char cmd[16];
487 struct scsi_sense_hdr sshdr;
488 int result;
489
490 if (sdev->no_report_opcodes || sdev->scsi_level < SCSI_SPC_3)
491 return -EINVAL;
492
493 memset(cmd, 0, 16);
494 cmd[0] = MAINTENANCE_IN;
495 cmd[1] = MI_REPORT_SUPPORTED_OPERATION_CODES;
496 cmd[2] = 1; /* One command format */
497 cmd[3] = opcode;
498 put_unaligned_be32(len, &cmd[6]);
499 memset(buffer, 0, len);
500
501 result = scsi_execute_req(sdev, cmd, DMA_FROM_DEVICE, buffer, len,
502 &sshdr, 30 * HZ, 3, NULL);
503
504 if (result < 0)
505 return result;
506 if (result && scsi_sense_valid(&sshdr) &&
507 sshdr.sense_key == ILLEGAL_REQUEST &&
508 (sshdr.asc == 0x20 || sshdr.asc == 0x24) && sshdr.ascq == 0x00)
509 return -EINVAL;
510
511 if ((buffer[1] & 3) == 3) /* Command supported */
512 return 1;
513
514 return 0;
515}
516EXPORT_SYMBOL(scsi_report_opcode);
517
518/**
519 * scsi_device_get - get an additional reference to a scsi_device
520 * @sdev: device to get a reference to
521 *
522 * Description: Gets a reference to the scsi_device and increments the use count
523 * of the underlying LLDD module. You must hold host_lock of the
524 * parent Scsi_Host or already have a reference when calling this.
525 *
526 * This will fail if a device is deleted or cancelled, or when the LLD module
527 * is in the process of being unloaded.
528 */
529int scsi_device_get(struct scsi_device *sdev)
530{
531 if (sdev->sdev_state == SDEV_DEL || sdev->sdev_state == SDEV_CANCEL)
532 goto fail;
533 if (!get_device(&sdev->sdev_gendev))
534 goto fail;
535 if (!try_module_get(sdev->host->hostt->module))
536 goto fail_put_device;
537 return 0;
538
539fail_put_device:
540 put_device(&sdev->sdev_gendev);
541fail:
542 return -ENXIO;
543}
544EXPORT_SYMBOL(scsi_device_get);
545
546/**
547 * scsi_device_put - release a reference to a scsi_device
548 * @sdev: device to release a reference on.
549 *
550 * Description: Release a reference to the scsi_device and decrements the use
551 * count of the underlying LLDD module. The device is freed once the last
552 * user vanishes.
553 */
554void scsi_device_put(struct scsi_device *sdev)
555{
556 module_put(sdev->host->hostt->module);
557 put_device(&sdev->sdev_gendev);
558}
559EXPORT_SYMBOL(scsi_device_put);
560
561/* helper for shost_for_each_device, see that for documentation */
562struct scsi_device *__scsi_iterate_devices(struct Scsi_Host *shost,
563 struct scsi_device *prev)
564{
565 struct list_head *list = (prev ? &prev->siblings : &shost->__devices);
566 struct scsi_device *next = NULL;
567 unsigned long flags;
568
569 spin_lock_irqsave(shost->host_lock, flags);
570 while (list->next != &shost->__devices) {
571 next = list_entry(list->next, struct scsi_device, siblings);
572 /* skip devices that we can't get a reference to */
573 if (!scsi_device_get(next))
574 break;
575 next = NULL;
576 list = list->next;
577 }
578 spin_unlock_irqrestore(shost->host_lock, flags);
579
580 if (prev)
581 scsi_device_put(prev);
582 return next;
583}
584EXPORT_SYMBOL(__scsi_iterate_devices);
585
586/**
587 * starget_for_each_device - helper to walk all devices of a target
588 * @starget: target whose devices we want to iterate over.
589 * @data: Opaque passed to each function call.
590 * @fn: Function to call on each device
591 *
592 * This traverses over each device of @starget. The devices have
593 * a reference that must be released by scsi_host_put when breaking
594 * out of the loop.
595 */
596void starget_for_each_device(struct scsi_target *starget, void *data,
597 void (*fn)(struct scsi_device *, void *))
598{
599 struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
600 struct scsi_device *sdev;
601
602 shost_for_each_device(sdev, shost) {
603 if ((sdev->channel == starget->channel) &&
604 (sdev->id == starget->id))
605 fn(sdev, data);
606 }
607}
608EXPORT_SYMBOL(starget_for_each_device);
609
610/**
611 * __starget_for_each_device - helper to walk all devices of a target (UNLOCKED)
612 * @starget: target whose devices we want to iterate over.
613 * @data: parameter for callback @fn()
614 * @fn: callback function that is invoked for each device
615 *
616 * This traverses over each device of @starget. It does _not_
617 * take a reference on the scsi_device, so the whole loop must be
618 * protected by shost->host_lock.
619 *
620 * Note: The only reason why drivers would want to use this is because
621 * they need to access the device list in irq context. Otherwise you
622 * really want to use starget_for_each_device instead.
623 **/
624void __starget_for_each_device(struct scsi_target *starget, void *data,
625 void (*fn)(struct scsi_device *, void *))
626{
627 struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
628 struct scsi_device *sdev;
629
630 __shost_for_each_device(sdev, shost) {
631 if ((sdev->channel == starget->channel) &&
632 (sdev->id == starget->id))
633 fn(sdev, data);
634 }
635}
636EXPORT_SYMBOL(__starget_for_each_device);
637
638/**
639 * __scsi_device_lookup_by_target - find a device given the target (UNLOCKED)
640 * @starget: SCSI target pointer
641 * @lun: SCSI Logical Unit Number
642 *
643 * Description: Looks up the scsi_device with the specified @lun for a given
644 * @starget. The returned scsi_device does not have an additional
645 * reference. You must hold the host's host_lock over this call and
646 * any access to the returned scsi_device. A scsi_device in state
647 * SDEV_DEL is skipped.
648 *
649 * Note: The only reason why drivers should use this is because
650 * they need to access the device list in irq context. Otherwise you
651 * really want to use scsi_device_lookup_by_target instead.
652 **/
653struct scsi_device *__scsi_device_lookup_by_target(struct scsi_target *starget,
654 u64 lun)
655{
656 struct scsi_device *sdev;
657
658 list_for_each_entry(sdev, &starget->devices, same_target_siblings) {
659 if (sdev->sdev_state == SDEV_DEL)
660 continue;
661 if (sdev->lun ==lun)
662 return sdev;
663 }
664
665 return NULL;
666}
667EXPORT_SYMBOL(__scsi_device_lookup_by_target);
668
669/**
670 * scsi_device_lookup_by_target - find a device given the target
671 * @starget: SCSI target pointer
672 * @lun: SCSI Logical Unit Number
673 *
674 * Description: Looks up the scsi_device with the specified @lun for a given
675 * @starget. The returned scsi_device has an additional reference that
676 * needs to be released with scsi_device_put once you're done with it.
677 **/
678struct scsi_device *scsi_device_lookup_by_target(struct scsi_target *starget,
679 u64 lun)
680{
681 struct scsi_device *sdev;
682 struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
683 unsigned long flags;
684
685 spin_lock_irqsave(shost->host_lock, flags);
686 sdev = __scsi_device_lookup_by_target(starget, lun);
687 if (sdev && scsi_device_get(sdev))
688 sdev = NULL;
689 spin_unlock_irqrestore(shost->host_lock, flags);
690
691 return sdev;
692}
693EXPORT_SYMBOL(scsi_device_lookup_by_target);
694
695/**
696 * __scsi_device_lookup - find a device given the host (UNLOCKED)
697 * @shost: SCSI host pointer
698 * @channel: SCSI channel (zero if only one channel)
699 * @id: SCSI target number (physical unit number)
700 * @lun: SCSI Logical Unit Number
701 *
702 * Description: Looks up the scsi_device with the specified @channel, @id, @lun
703 * for a given host. The returned scsi_device does not have an additional
704 * reference. You must hold the host's host_lock over this call and any access
705 * to the returned scsi_device.
706 *
707 * Note: The only reason why drivers would want to use this is because
708 * they need to access the device list in irq context. Otherwise you
709 * really want to use scsi_device_lookup instead.
710 **/
711struct scsi_device *__scsi_device_lookup(struct Scsi_Host *shost,
712 uint channel, uint id, u64 lun)
713{
714 struct scsi_device *sdev;
715
716 list_for_each_entry(sdev, &shost->__devices, siblings) {
717 if (sdev->sdev_state == SDEV_DEL)
718 continue;
719 if (sdev->channel == channel && sdev->id == id &&
720 sdev->lun ==lun)
721 return sdev;
722 }
723
724 return NULL;
725}
726EXPORT_SYMBOL(__scsi_device_lookup);
727
728/**
729 * scsi_device_lookup - find a device given the host
730 * @shost: SCSI host pointer
731 * @channel: SCSI channel (zero if only one channel)
732 * @id: SCSI target number (physical unit number)
733 * @lun: SCSI Logical Unit Number
734 *
735 * Description: Looks up the scsi_device with the specified @channel, @id, @lun
736 * for a given host. The returned scsi_device has an additional reference that
737 * needs to be released with scsi_device_put once you're done with it.
738 **/
739struct scsi_device *scsi_device_lookup(struct Scsi_Host *shost,
740 uint channel, uint id, u64 lun)
741{
742 struct scsi_device *sdev;
743 unsigned long flags;
744
745 spin_lock_irqsave(shost->host_lock, flags);
746 sdev = __scsi_device_lookup(shost, channel, id, lun);
747 if (sdev && scsi_device_get(sdev))
748 sdev = NULL;
749 spin_unlock_irqrestore(shost->host_lock, flags);
750
751 return sdev;
752}
753EXPORT_SYMBOL(scsi_device_lookup);
754
755MODULE_DESCRIPTION("SCSI core");
756MODULE_LICENSE("GPL");
757
758module_param(scsi_logging_level, int, S_IRUGO|S_IWUSR);
759MODULE_PARM_DESC(scsi_logging_level, "a bit mask of logging levels");
760
761static int __init init_scsi(void)
762{
763 int error;
764
765 error = scsi_init_procfs();
766 if (error)
767 goto cleanup_queue;
768 error = scsi_init_devinfo();
769 if (error)
770 goto cleanup_procfs;
771 error = scsi_init_hosts();
772 if (error)
773 goto cleanup_devlist;
774 error = scsi_init_sysctl();
775 if (error)
776 goto cleanup_hosts;
777 error = scsi_sysfs_register();
778 if (error)
779 goto cleanup_sysctl;
780
781 scsi_netlink_init();
782
783 printk(KERN_NOTICE "SCSI subsystem initialized\n");
784 return 0;
785
786cleanup_sysctl:
787 scsi_exit_sysctl();
788cleanup_hosts:
789 scsi_exit_hosts();
790cleanup_devlist:
791 scsi_exit_devinfo();
792cleanup_procfs:
793 scsi_exit_procfs();
794cleanup_queue:
795 scsi_exit_queue();
796 printk(KERN_ERR "SCSI subsystem failed to initialize, error = %d\n",
797 -error);
798 return error;
799}
800
801static void __exit exit_scsi(void)
802{
803 scsi_netlink_exit();
804 scsi_sysfs_unregister();
805 scsi_exit_sysctl();
806 scsi_exit_hosts();
807 scsi_exit_devinfo();
808 scsi_exit_procfs();
809 scsi_exit_queue();
810}
811
812subsys_initcall(init_scsi);
813module_exit(exit_scsi);
1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * scsi.c Copyright (C) 1992 Drew Eckhardt
4 * Copyright (C) 1993, 1994, 1995, 1999 Eric Youngdale
5 * Copyright (C) 2002, 2003 Christoph Hellwig
6 *
7 * generic mid-level SCSI driver
8 * Initial versions: Drew Eckhardt
9 * Subsequent revisions: Eric Youngdale
10 *
11 * <drew@colorado.edu>
12 *
13 * Bug correction thanks go to :
14 * Rik Faith <faith@cs.unc.edu>
15 * Tommy Thorn <tthorn>
16 * Thomas Wuensche <tw@fgb1.fgb.mw.tu-muenchen.de>
17 *
18 * Modified by Eric Youngdale eric@andante.org or ericy@gnu.ai.mit.edu to
19 * add scatter-gather, multiple outstanding request, and other
20 * enhancements.
21 *
22 * Native multichannel, wide scsi, /proc/scsi and hot plugging
23 * support added by Michael Neuffer <mike@i-connect.net>
24 *
25 * Added request_module("scsi_hostadapter") for kerneld:
26 * (Put an "alias scsi_hostadapter your_hostadapter" in /etc/modprobe.conf)
27 * Bjorn Ekwall <bj0rn@blox.se>
28 * (changed to kmod)
29 *
30 * Major improvements to the timeout, abort, and reset processing,
31 * as well as performance modifications for large queue depths by
32 * Leonard N. Zubkoff <lnz@dandelion.com>
33 *
34 * Converted cli() code to spinlocks, Ingo Molnar
35 *
36 * Jiffies wrap fixes (host->resetting), 3 Dec 1998 Andrea Arcangeli
37 *
38 * out_of_space hacks, D. Gilbert (dpg) 990608
39 */
40
41#include <linux/module.h>
42#include <linux/moduleparam.h>
43#include <linux/kernel.h>
44#include <linux/timer.h>
45#include <linux/string.h>
46#include <linux/slab.h>
47#include <linux/blkdev.h>
48#include <linux/delay.h>
49#include <linux/init.h>
50#include <linux/completion.h>
51#include <linux/unistd.h>
52#include <linux/spinlock.h>
53#include <linux/kmod.h>
54#include <linux/interrupt.h>
55#include <linux/notifier.h>
56#include <linux/cpu.h>
57#include <linux/mutex.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#ifdef CONFIG_SCSI_LOGGING
89void scsi_log_send(struct scsi_cmnd *cmd)
90{
91 unsigned int level;
92
93 /*
94 * If ML QUEUE log level is greater than or equal to:
95 *
96 * 1: nothing (match completion)
97 *
98 * 2: log opcode + command of all commands + cmd address
99 *
100 * 3: same as 2
101 *
102 * 4: same as 3
103 */
104 if (unlikely(scsi_logging_level)) {
105 level = SCSI_LOG_LEVEL(SCSI_LOG_MLQUEUE_SHIFT,
106 SCSI_LOG_MLQUEUE_BITS);
107 if (level > 1) {
108 scmd_printk(KERN_INFO, cmd,
109 "Send: scmd 0x%p\n", cmd);
110 scsi_print_command(cmd);
111 }
112 }
113}
114
115void scsi_log_completion(struct scsi_cmnd *cmd, int disposition)
116{
117 unsigned int level;
118
119 /*
120 * If ML COMPLETE log level is greater than or equal to:
121 *
122 * 1: log disposition, result, opcode + command, and conditionally
123 * sense data for failures or non SUCCESS dispositions.
124 *
125 * 2: same as 1 but for all command completions.
126 *
127 * 3: same as 2
128 *
129 * 4: same as 3 plus dump extra junk
130 */
131 if (unlikely(scsi_logging_level)) {
132 level = SCSI_LOG_LEVEL(SCSI_LOG_MLCOMPLETE_SHIFT,
133 SCSI_LOG_MLCOMPLETE_BITS);
134 if (((level > 0) && (cmd->result || disposition != SUCCESS)) ||
135 (level > 1)) {
136 scsi_print_result(cmd, "Done", disposition);
137 scsi_print_command(cmd);
138 if (scsi_status_is_check_condition(cmd->result))
139 scsi_print_sense(cmd);
140 if (level > 3)
141 scmd_printk(KERN_INFO, cmd,
142 "scsi host busy %d failed %d\n",
143 scsi_host_busy(cmd->device->host),
144 cmd->device->host->host_failed);
145 }
146 }
147}
148#endif
149
150/**
151 * scsi_finish_command - cleanup and pass command back to upper layer
152 * @cmd: the command
153 *
154 * Description: Pass command off to upper layer for finishing of I/O
155 * request, waking processes that are waiting on results,
156 * etc.
157 */
158void scsi_finish_command(struct scsi_cmnd *cmd)
159{
160 struct scsi_device *sdev = cmd->device;
161 struct scsi_target *starget = scsi_target(sdev);
162 struct Scsi_Host *shost = sdev->host;
163 struct scsi_driver *drv;
164 unsigned int good_bytes;
165
166 scsi_device_unbusy(sdev, cmd);
167
168 /*
169 * Clear the flags that say that the device/target/host is no longer
170 * capable of accepting new commands.
171 */
172 if (atomic_read(&shost->host_blocked))
173 atomic_set(&shost->host_blocked, 0);
174 if (atomic_read(&starget->target_blocked))
175 atomic_set(&starget->target_blocked, 0);
176 if (atomic_read(&sdev->device_blocked))
177 atomic_set(&sdev->device_blocked, 0);
178
179 SCSI_LOG_MLCOMPLETE(4, sdev_printk(KERN_INFO, sdev,
180 "Notifying upper driver of completion "
181 "(result %x)\n", cmd->result));
182
183 good_bytes = scsi_bufflen(cmd);
184 if (!blk_rq_is_passthrough(scsi_cmd_to_rq(cmd))) {
185 int old_good_bytes = good_bytes;
186 drv = scsi_cmd_to_driver(cmd);
187 if (drv->done)
188 good_bytes = drv->done(cmd);
189 /*
190 * USB may not give sense identifying bad sector and
191 * simply return a residue instead, so subtract off the
192 * residue if drv->done() error processing indicates no
193 * change to the completion length.
194 */
195 if (good_bytes == old_good_bytes)
196 good_bytes -= scsi_get_resid(cmd);
197 }
198 scsi_io_completion(cmd, good_bytes);
199}
200
201
202/*
203 * 4096 is big enough for saturating fast SCSI LUNs.
204 */
205int scsi_device_max_queue_depth(struct scsi_device *sdev)
206{
207 return min_t(int, sdev->host->can_queue, 4096);
208}
209
210/**
211 * scsi_change_queue_depth - change a device's queue depth
212 * @sdev: SCSI Device in question
213 * @depth: number of commands allowed to be queued to the driver
214 *
215 * Sets the device queue depth and returns the new value.
216 */
217int scsi_change_queue_depth(struct scsi_device *sdev, int depth)
218{
219 depth = min_t(int, depth, scsi_device_max_queue_depth(sdev));
220
221 if (depth > 0) {
222 sdev->queue_depth = depth;
223 wmb();
224 }
225
226 if (sdev->request_queue)
227 blk_set_queue_depth(sdev->request_queue, depth);
228
229 sbitmap_resize(&sdev->budget_map, sdev->queue_depth);
230
231 return sdev->queue_depth;
232}
233EXPORT_SYMBOL(scsi_change_queue_depth);
234
235/**
236 * scsi_track_queue_full - track QUEUE_FULL events to adjust queue depth
237 * @sdev: SCSI Device in question
238 * @depth: Current number of outstanding SCSI commands on this device,
239 * not counting the one returned as QUEUE_FULL.
240 *
241 * Description: This function will track successive QUEUE_FULL events on a
242 * specific SCSI device to determine if and when there is a
243 * need to adjust the queue depth on the device.
244 *
245 * Returns: 0 - No change needed, >0 - Adjust queue depth to this new depth,
246 * -1 - Drop back to untagged operation using host->cmd_per_lun
247 * as the untagged command depth
248 *
249 * Lock Status: None held on entry
250 *
251 * Notes: Low level drivers may call this at any time and we will do
252 * "The Right Thing." We are interrupt context safe.
253 */
254int scsi_track_queue_full(struct scsi_device *sdev, int depth)
255{
256
257 /*
258 * Don't let QUEUE_FULLs on the same
259 * jiffies count, they could all be from
260 * same event.
261 */
262 if ((jiffies >> 4) == (sdev->last_queue_full_time >> 4))
263 return 0;
264
265 sdev->last_queue_full_time = jiffies;
266 if (sdev->last_queue_full_depth != depth) {
267 sdev->last_queue_full_count = 1;
268 sdev->last_queue_full_depth = depth;
269 } else {
270 sdev->last_queue_full_count++;
271 }
272
273 if (sdev->last_queue_full_count <= 10)
274 return 0;
275
276 return scsi_change_queue_depth(sdev, depth);
277}
278EXPORT_SYMBOL(scsi_track_queue_full);
279
280/**
281 * scsi_vpd_inquiry - Request a device provide us with a VPD page
282 * @sdev: The device to ask
283 * @buffer: Where to put the result
284 * @page: Which Vital Product Data to return
285 * @len: The length of the buffer
286 *
287 * This is an internal helper function. You probably want to use
288 * scsi_get_vpd_page instead.
289 *
290 * Returns size of the vpd page on success or a negative error number.
291 */
292static int scsi_vpd_inquiry(struct scsi_device *sdev, unsigned char *buffer,
293 u8 page, unsigned len)
294{
295 int result;
296 unsigned char cmd[16];
297
298 if (len < 4)
299 return -EINVAL;
300
301 cmd[0] = INQUIRY;
302 cmd[1] = 1; /* EVPD */
303 cmd[2] = page;
304 cmd[3] = len >> 8;
305 cmd[4] = len & 0xff;
306 cmd[5] = 0; /* Control byte */
307
308 /*
309 * I'm not convinced we need to try quite this hard to get VPD, but
310 * all the existing users tried this hard.
311 */
312 result = scsi_execute_req(sdev, cmd, DMA_FROM_DEVICE, buffer,
313 len, NULL, 30 * HZ, 3, NULL);
314 if (result)
315 return -EIO;
316
317 /* Sanity check that we got the page back that we asked for */
318 if (buffer[1] != page)
319 return -EIO;
320
321 return get_unaligned_be16(&buffer[2]) + 4;
322}
323
324static int scsi_get_vpd_size(struct scsi_device *sdev, u8 page)
325{
326 unsigned char vpd_header[SCSI_VPD_HEADER_SIZE] __aligned(4);
327 int result;
328
329 /*
330 * Fetch the VPD page header to find out how big the page
331 * is. This is done to prevent problems on legacy devices
332 * which can not handle allocation lengths as large as
333 * potentially requested by the caller.
334 */
335 result = scsi_vpd_inquiry(sdev, vpd_header, page, sizeof(vpd_header));
336 if (result < 0)
337 return 0;
338
339 if (result < SCSI_VPD_HEADER_SIZE) {
340 dev_warn_once(&sdev->sdev_gendev,
341 "%s: short VPD page 0x%02x length: %d bytes\n",
342 __func__, page, result);
343 return 0;
344 }
345
346 return result;
347}
348
349/**
350 * scsi_get_vpd_page - Get Vital Product Data from a SCSI device
351 * @sdev: The device to ask
352 * @page: Which Vital Product Data to return
353 * @buf: where to store the VPD
354 * @buf_len: number of bytes in the VPD buffer area
355 *
356 * SCSI devices may optionally supply Vital Product Data. Each 'page'
357 * of VPD is defined in the appropriate SCSI document (eg SPC, SBC).
358 * If the device supports this VPD page, this routine fills @buf
359 * with the data from that page and return 0. If the VPD page is not
360 * supported or its content cannot be retrieved, -EINVAL is returned.
361 */
362int scsi_get_vpd_page(struct scsi_device *sdev, u8 page, unsigned char *buf,
363 int buf_len)
364{
365 int result, vpd_len;
366
367 if (!scsi_device_supports_vpd(sdev))
368 return -EINVAL;
369
370 vpd_len = scsi_get_vpd_size(sdev, page);
371 if (vpd_len <= 0)
372 return -EINVAL;
373
374 vpd_len = min(vpd_len, buf_len);
375
376 /*
377 * Fetch the actual page. Since the appropriate size was reported
378 * by the device it is now safe to ask for something bigger.
379 */
380 memset(buf, 0, buf_len);
381 result = scsi_vpd_inquiry(sdev, buf, page, vpd_len);
382 if (result < 0)
383 return -EINVAL;
384 else if (result > vpd_len)
385 dev_warn_once(&sdev->sdev_gendev,
386 "%s: VPD page 0x%02x result %d > %d bytes\n",
387 __func__, page, result, vpd_len);
388
389 return 0;
390}
391EXPORT_SYMBOL_GPL(scsi_get_vpd_page);
392
393/**
394 * scsi_get_vpd_buf - Get Vital Product Data from a SCSI device
395 * @sdev: The device to ask
396 * @page: Which Vital Product Data to return
397 *
398 * Returns %NULL upon failure.
399 */
400static struct scsi_vpd *scsi_get_vpd_buf(struct scsi_device *sdev, u8 page)
401{
402 struct scsi_vpd *vpd_buf;
403 int vpd_len, result;
404
405 vpd_len = scsi_get_vpd_size(sdev, page);
406 if (vpd_len <= 0)
407 return NULL;
408
409retry_pg:
410 /*
411 * Fetch the actual page. Since the appropriate size was reported
412 * by the device it is now safe to ask for something bigger.
413 */
414 vpd_buf = kmalloc(sizeof(*vpd_buf) + vpd_len, GFP_KERNEL);
415 if (!vpd_buf)
416 return NULL;
417
418 result = scsi_vpd_inquiry(sdev, vpd_buf->data, page, vpd_len);
419 if (result < 0) {
420 kfree(vpd_buf);
421 return NULL;
422 }
423 if (result > vpd_len) {
424 dev_warn_once(&sdev->sdev_gendev,
425 "%s: VPD page 0x%02x result %d > %d bytes\n",
426 __func__, page, result, vpd_len);
427 vpd_len = result;
428 kfree(vpd_buf);
429 goto retry_pg;
430 }
431
432 vpd_buf->len = result;
433
434 return vpd_buf;
435}
436
437static void scsi_update_vpd_page(struct scsi_device *sdev, u8 page,
438 struct scsi_vpd __rcu **sdev_vpd_buf)
439{
440 struct scsi_vpd *vpd_buf;
441
442 vpd_buf = scsi_get_vpd_buf(sdev, page);
443 if (!vpd_buf)
444 return;
445
446 mutex_lock(&sdev->inquiry_mutex);
447 vpd_buf = rcu_replace_pointer(*sdev_vpd_buf, vpd_buf,
448 lockdep_is_held(&sdev->inquiry_mutex));
449 mutex_unlock(&sdev->inquiry_mutex);
450
451 if (vpd_buf)
452 kfree_rcu(vpd_buf, rcu);
453}
454
455/**
456 * scsi_attach_vpd - Attach Vital Product Data to a SCSI device structure
457 * @sdev: The device to ask
458 *
459 * Attach the 'Device Identification' VPD page (0x83) and the
460 * 'Unit Serial Number' VPD page (0x80) to a SCSI device
461 * structure. This information can be used to identify the device
462 * uniquely.
463 */
464void scsi_attach_vpd(struct scsi_device *sdev)
465{
466 int i;
467 struct scsi_vpd *vpd_buf;
468
469 if (!scsi_device_supports_vpd(sdev))
470 return;
471
472 /* Ask for all the pages supported by this device */
473 vpd_buf = scsi_get_vpd_buf(sdev, 0);
474 if (!vpd_buf)
475 return;
476
477 for (i = 4; i < vpd_buf->len; i++) {
478 if (vpd_buf->data[i] == 0x0)
479 scsi_update_vpd_page(sdev, 0x0, &sdev->vpd_pg0);
480 if (vpd_buf->data[i] == 0x80)
481 scsi_update_vpd_page(sdev, 0x80, &sdev->vpd_pg80);
482 if (vpd_buf->data[i] == 0x83)
483 scsi_update_vpd_page(sdev, 0x83, &sdev->vpd_pg83);
484 if (vpd_buf->data[i] == 0x89)
485 scsi_update_vpd_page(sdev, 0x89, &sdev->vpd_pg89);
486 if (vpd_buf->data[i] == 0xb0)
487 scsi_update_vpd_page(sdev, 0xb0, &sdev->vpd_pgb0);
488 if (vpd_buf->data[i] == 0xb1)
489 scsi_update_vpd_page(sdev, 0xb1, &sdev->vpd_pgb1);
490 if (vpd_buf->data[i] == 0xb2)
491 scsi_update_vpd_page(sdev, 0xb2, &sdev->vpd_pgb2);
492 }
493 kfree(vpd_buf);
494}
495
496/**
497 * scsi_report_opcode - Find out if a given command opcode is supported
498 * @sdev: scsi device to query
499 * @buffer: scratch buffer (must be at least 20 bytes long)
500 * @len: length of buffer
501 * @opcode: opcode for command to look up
502 *
503 * Uses the REPORT SUPPORTED OPERATION CODES to look up the given
504 * opcode. Returns -EINVAL if RSOC fails, 0 if the command opcode is
505 * unsupported and 1 if the device claims to support the command.
506 */
507int scsi_report_opcode(struct scsi_device *sdev, unsigned char *buffer,
508 unsigned int len, unsigned char opcode)
509{
510 unsigned char cmd[16];
511 struct scsi_sense_hdr sshdr;
512 int result, request_len;
513
514 if (sdev->no_report_opcodes || sdev->scsi_level < SCSI_SPC_3)
515 return -EINVAL;
516
517 /* RSOC header + size of command we are asking about */
518 request_len = 4 + COMMAND_SIZE(opcode);
519 if (request_len > len) {
520 dev_warn_once(&sdev->sdev_gendev,
521 "%s: len %u bytes, opcode 0x%02x needs %u\n",
522 __func__, len, opcode, request_len);
523 return -EINVAL;
524 }
525
526 memset(cmd, 0, 16);
527 cmd[0] = MAINTENANCE_IN;
528 cmd[1] = MI_REPORT_SUPPORTED_OPERATION_CODES;
529 cmd[2] = 1; /* One command format */
530 cmd[3] = opcode;
531 put_unaligned_be32(request_len, &cmd[6]);
532 memset(buffer, 0, len);
533
534 result = scsi_execute_req(sdev, cmd, DMA_FROM_DEVICE, buffer,
535 request_len, &sshdr, 30 * HZ, 3, NULL);
536
537 if (result < 0)
538 return result;
539 if (result && scsi_sense_valid(&sshdr) &&
540 sshdr.sense_key == ILLEGAL_REQUEST &&
541 (sshdr.asc == 0x20 || sshdr.asc == 0x24) && sshdr.ascq == 0x00)
542 return -EINVAL;
543
544 if ((buffer[1] & 3) == 3) /* Command supported */
545 return 1;
546
547 return 0;
548}
549EXPORT_SYMBOL(scsi_report_opcode);
550
551/**
552 * scsi_device_get - get an additional reference to a scsi_device
553 * @sdev: device to get a reference to
554 *
555 * Description: Gets a reference to the scsi_device and increments the use count
556 * of the underlying LLDD module. You must hold host_lock of the
557 * parent Scsi_Host or already have a reference when calling this.
558 *
559 * This will fail if a device is deleted or cancelled, or when the LLD module
560 * is in the process of being unloaded.
561 */
562int scsi_device_get(struct scsi_device *sdev)
563{
564 if (sdev->sdev_state == SDEV_DEL || sdev->sdev_state == SDEV_CANCEL)
565 goto fail;
566 if (!try_module_get(sdev->host->hostt->module))
567 goto fail;
568 if (!get_device(&sdev->sdev_gendev))
569 goto fail_put_module;
570 return 0;
571
572fail_put_module:
573 module_put(sdev->host->hostt->module);
574fail:
575 return -ENXIO;
576}
577EXPORT_SYMBOL(scsi_device_get);
578
579/**
580 * scsi_device_put - release a reference to a scsi_device
581 * @sdev: device to release a reference on.
582 *
583 * Description: Release a reference to the scsi_device and decrements the use
584 * count of the underlying LLDD module. The device is freed once the last
585 * user vanishes.
586 */
587void scsi_device_put(struct scsi_device *sdev)
588{
589 struct module *mod = sdev->host->hostt->module;
590
591 put_device(&sdev->sdev_gendev);
592 module_put(mod);
593}
594EXPORT_SYMBOL(scsi_device_put);
595
596/* helper for shost_for_each_device, see that for documentation */
597struct scsi_device *__scsi_iterate_devices(struct Scsi_Host *shost,
598 struct scsi_device *prev)
599{
600 struct list_head *list = (prev ? &prev->siblings : &shost->__devices);
601 struct scsi_device *next = NULL;
602 unsigned long flags;
603
604 spin_lock_irqsave(shost->host_lock, flags);
605 while (list->next != &shost->__devices) {
606 next = list_entry(list->next, struct scsi_device, siblings);
607 /* skip devices that we can't get a reference to */
608 if (!scsi_device_get(next))
609 break;
610 next = NULL;
611 list = list->next;
612 }
613 spin_unlock_irqrestore(shost->host_lock, flags);
614
615 if (prev)
616 scsi_device_put(prev);
617 return next;
618}
619EXPORT_SYMBOL(__scsi_iterate_devices);
620
621/**
622 * starget_for_each_device - helper to walk all devices of a target
623 * @starget: target whose devices we want to iterate over.
624 * @data: Opaque passed to each function call.
625 * @fn: Function to call on each device
626 *
627 * This traverses over each device of @starget. The devices have
628 * a reference that must be released by scsi_host_put when breaking
629 * out of the loop.
630 */
631void starget_for_each_device(struct scsi_target *starget, void *data,
632 void (*fn)(struct scsi_device *, void *))
633{
634 struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
635 struct scsi_device *sdev;
636
637 shost_for_each_device(sdev, shost) {
638 if ((sdev->channel == starget->channel) &&
639 (sdev->id == starget->id))
640 fn(sdev, data);
641 }
642}
643EXPORT_SYMBOL(starget_for_each_device);
644
645/**
646 * __starget_for_each_device - helper to walk all devices of a target (UNLOCKED)
647 * @starget: target whose devices we want to iterate over.
648 * @data: parameter for callback @fn()
649 * @fn: callback function that is invoked for each device
650 *
651 * This traverses over each device of @starget. It does _not_
652 * take a reference on the scsi_device, so the whole loop must be
653 * protected by shost->host_lock.
654 *
655 * Note: The only reason why drivers would want to use this is because
656 * they need to access the device list in irq context. Otherwise you
657 * really want to use starget_for_each_device instead.
658 **/
659void __starget_for_each_device(struct scsi_target *starget, void *data,
660 void (*fn)(struct scsi_device *, void *))
661{
662 struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
663 struct scsi_device *sdev;
664
665 __shost_for_each_device(sdev, shost) {
666 if ((sdev->channel == starget->channel) &&
667 (sdev->id == starget->id))
668 fn(sdev, data);
669 }
670}
671EXPORT_SYMBOL(__starget_for_each_device);
672
673/**
674 * __scsi_device_lookup_by_target - find a device given the target (UNLOCKED)
675 * @starget: SCSI target pointer
676 * @lun: SCSI Logical Unit Number
677 *
678 * Description: Looks up the scsi_device with the specified @lun for a given
679 * @starget. The returned scsi_device does not have an additional
680 * reference. You must hold the host's host_lock over this call and
681 * any access to the returned scsi_device. A scsi_device in state
682 * SDEV_DEL is skipped.
683 *
684 * Note: The only reason why drivers should use this is because
685 * they need to access the device list in irq context. Otherwise you
686 * really want to use scsi_device_lookup_by_target instead.
687 **/
688struct scsi_device *__scsi_device_lookup_by_target(struct scsi_target *starget,
689 u64 lun)
690{
691 struct scsi_device *sdev;
692
693 list_for_each_entry(sdev, &starget->devices, same_target_siblings) {
694 if (sdev->sdev_state == SDEV_DEL)
695 continue;
696 if (sdev->lun ==lun)
697 return sdev;
698 }
699
700 return NULL;
701}
702EXPORT_SYMBOL(__scsi_device_lookup_by_target);
703
704/**
705 * scsi_device_lookup_by_target - find a device given the target
706 * @starget: SCSI target pointer
707 * @lun: SCSI Logical Unit Number
708 *
709 * Description: Looks up the scsi_device with the specified @lun for a given
710 * @starget. The returned scsi_device has an additional reference that
711 * needs to be released with scsi_device_put once you're done with it.
712 **/
713struct scsi_device *scsi_device_lookup_by_target(struct scsi_target *starget,
714 u64 lun)
715{
716 struct scsi_device *sdev;
717 struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
718 unsigned long flags;
719
720 spin_lock_irqsave(shost->host_lock, flags);
721 sdev = __scsi_device_lookup_by_target(starget, lun);
722 if (sdev && scsi_device_get(sdev))
723 sdev = NULL;
724 spin_unlock_irqrestore(shost->host_lock, flags);
725
726 return sdev;
727}
728EXPORT_SYMBOL(scsi_device_lookup_by_target);
729
730/**
731 * __scsi_device_lookup - find a device given the host (UNLOCKED)
732 * @shost: SCSI host pointer
733 * @channel: SCSI channel (zero if only one channel)
734 * @id: SCSI target number (physical unit number)
735 * @lun: SCSI Logical Unit Number
736 *
737 * Description: Looks up the scsi_device with the specified @channel, @id, @lun
738 * for a given host. The returned scsi_device does not have an additional
739 * reference. You must hold the host's host_lock over this call and any access
740 * to the returned scsi_device.
741 *
742 * Note: The only reason why drivers would want to use this is because
743 * they need to access the device list in irq context. Otherwise you
744 * really want to use scsi_device_lookup instead.
745 **/
746struct scsi_device *__scsi_device_lookup(struct Scsi_Host *shost,
747 uint channel, uint id, u64 lun)
748{
749 struct scsi_device *sdev;
750
751 list_for_each_entry(sdev, &shost->__devices, siblings) {
752 if (sdev->sdev_state == SDEV_DEL)
753 continue;
754 if (sdev->channel == channel && sdev->id == id &&
755 sdev->lun ==lun)
756 return sdev;
757 }
758
759 return NULL;
760}
761EXPORT_SYMBOL(__scsi_device_lookup);
762
763/**
764 * scsi_device_lookup - find a device given the host
765 * @shost: SCSI host pointer
766 * @channel: SCSI channel (zero if only one channel)
767 * @id: SCSI target number (physical unit number)
768 * @lun: SCSI Logical Unit Number
769 *
770 * Description: Looks up the scsi_device with the specified @channel, @id, @lun
771 * for a given host. The returned scsi_device has an additional reference that
772 * needs to be released with scsi_device_put once you're done with it.
773 **/
774struct scsi_device *scsi_device_lookup(struct Scsi_Host *shost,
775 uint channel, uint id, u64 lun)
776{
777 struct scsi_device *sdev;
778 unsigned long flags;
779
780 spin_lock_irqsave(shost->host_lock, flags);
781 sdev = __scsi_device_lookup(shost, channel, id, lun);
782 if (sdev && scsi_device_get(sdev))
783 sdev = NULL;
784 spin_unlock_irqrestore(shost->host_lock, flags);
785
786 return sdev;
787}
788EXPORT_SYMBOL(scsi_device_lookup);
789
790MODULE_DESCRIPTION("SCSI core");
791MODULE_LICENSE("GPL");
792
793module_param(scsi_logging_level, int, S_IRUGO|S_IWUSR);
794MODULE_PARM_DESC(scsi_logging_level, "a bit mask of logging levels");
795
796static int __init init_scsi(void)
797{
798 int error;
799
800 error = scsi_init_procfs();
801 if (error)
802 goto cleanup_queue;
803 error = scsi_init_devinfo();
804 if (error)
805 goto cleanup_procfs;
806 error = scsi_init_hosts();
807 if (error)
808 goto cleanup_devlist;
809 error = scsi_init_sysctl();
810 if (error)
811 goto cleanup_hosts;
812 error = scsi_sysfs_register();
813 if (error)
814 goto cleanup_sysctl;
815
816 scsi_netlink_init();
817
818 printk(KERN_NOTICE "SCSI subsystem initialized\n");
819 return 0;
820
821cleanup_sysctl:
822 scsi_exit_sysctl();
823cleanup_hosts:
824 scsi_exit_hosts();
825cleanup_devlist:
826 scsi_exit_devinfo();
827cleanup_procfs:
828 scsi_exit_procfs();
829cleanup_queue:
830 scsi_exit_queue();
831 printk(KERN_ERR "SCSI subsystem failed to initialize, error = %d\n",
832 -error);
833 return error;
834}
835
836static void __exit exit_scsi(void)
837{
838 scsi_netlink_exit();
839 scsi_sysfs_unregister();
840 scsi_exit_sysctl();
841 scsi_exit_hosts();
842 scsi_exit_devinfo();
843 scsi_exit_procfs();
844 scsi_exit_queue();
845}
846
847subsys_initcall(init_scsi);
848module_exit(exit_scsi);