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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 atomic_read(&cmd->device->host->host_busy),
171 cmd->device->host->host_failed);
172 }
173 }
174}
175#endif
176
177/**
178 * scsi_cmd_get_serial - Assign a serial number to a command
179 * @host: the scsi host
180 * @cmd: command to assign serial number to
181 *
182 * Description: a serial number identifies a request for error recovery
183 * and debugging purposes. Protected by the Host_Lock of host.
184 */
185void scsi_cmd_get_serial(struct Scsi_Host *host, struct scsi_cmnd *cmd)
186{
187 cmd->serial_number = host->cmd_serial_number++;
188 if (cmd->serial_number == 0)
189 cmd->serial_number = host->cmd_serial_number++;
190}
191EXPORT_SYMBOL(scsi_cmd_get_serial);
192
193/**
194 * scsi_finish_command - cleanup and pass command back to upper layer
195 * @cmd: the command
196 *
197 * Description: Pass command off to upper layer for finishing of I/O
198 * request, waking processes that are waiting on results,
199 * etc.
200 */
201void scsi_finish_command(struct scsi_cmnd *cmd)
202{
203 struct scsi_device *sdev = cmd->device;
204 struct scsi_target *starget = scsi_target(sdev);
205 struct Scsi_Host *shost = sdev->host;
206 struct scsi_driver *drv;
207 unsigned int good_bytes;
208
209 scsi_device_unbusy(sdev);
210
211 /*
212 * Clear the flags that say that the device/target/host is no longer
213 * capable of accepting new commands.
214 */
215 if (atomic_read(&shost->host_blocked))
216 atomic_set(&shost->host_blocked, 0);
217 if (atomic_read(&starget->target_blocked))
218 atomic_set(&starget->target_blocked, 0);
219 if (atomic_read(&sdev->device_blocked))
220 atomic_set(&sdev->device_blocked, 0);
221
222 /*
223 * If we have valid sense information, then some kind of recovery
224 * must have taken place. Make a note of this.
225 */
226 if (SCSI_SENSE_VALID(cmd))
227 cmd->result |= (DRIVER_SENSE << 24);
228
229 SCSI_LOG_MLCOMPLETE(4, sdev_printk(KERN_INFO, sdev,
230 "Notifying upper driver of completion "
231 "(result %x)\n", cmd->result));
232
233 good_bytes = scsi_bufflen(cmd);
234 if (!blk_rq_is_passthrough(cmd->request)) {
235 int old_good_bytes = good_bytes;
236 drv = scsi_cmd_to_driver(cmd);
237 if (drv->done)
238 good_bytes = drv->done(cmd);
239 /*
240 * USB may not give sense identifying bad sector and
241 * simply return a residue instead, so subtract off the
242 * residue if drv->done() error processing indicates no
243 * change to the completion length.
244 */
245 if (good_bytes == old_good_bytes)
246 good_bytes -= scsi_get_resid(cmd);
247 }
248 scsi_io_completion(cmd, good_bytes);
249}
250
251/**
252 * scsi_change_queue_depth - change a device's queue depth
253 * @sdev: SCSI Device in question
254 * @depth: number of commands allowed to be queued to the driver
255 *
256 * Sets the device queue depth and returns the new value.
257 */
258int scsi_change_queue_depth(struct scsi_device *sdev, int depth)
259{
260 if (depth > 0) {
261 sdev->queue_depth = depth;
262 wmb();
263 }
264
265 if (sdev->request_queue)
266 blk_set_queue_depth(sdev->request_queue, depth);
267
268 return sdev->queue_depth;
269}
270EXPORT_SYMBOL(scsi_change_queue_depth);
271
272/**
273 * scsi_track_queue_full - track QUEUE_FULL events to adjust queue depth
274 * @sdev: SCSI Device in question
275 * @depth: Current number of outstanding SCSI commands on this device,
276 * not counting the one returned as QUEUE_FULL.
277 *
278 * Description: This function will track successive QUEUE_FULL events on a
279 * specific SCSI device to determine if and when there is a
280 * need to adjust the queue depth on the device.
281 *
282 * Returns: 0 - No change needed, >0 - Adjust queue depth to this new depth,
283 * -1 - Drop back to untagged operation using host->cmd_per_lun
284 * as the untagged command depth
285 *
286 * Lock Status: None held on entry
287 *
288 * Notes: Low level drivers may call this at any time and we will do
289 * "The Right Thing." We are interrupt context safe.
290 */
291int scsi_track_queue_full(struct scsi_device *sdev, int depth)
292{
293
294 /*
295 * Don't let QUEUE_FULLs on the same
296 * jiffies count, they could all be from
297 * same event.
298 */
299 if ((jiffies >> 4) == (sdev->last_queue_full_time >> 4))
300 return 0;
301
302 sdev->last_queue_full_time = jiffies;
303 if (sdev->last_queue_full_depth != depth) {
304 sdev->last_queue_full_count = 1;
305 sdev->last_queue_full_depth = depth;
306 } else {
307 sdev->last_queue_full_count++;
308 }
309
310 if (sdev->last_queue_full_count <= 10)
311 return 0;
312
313 return scsi_change_queue_depth(sdev, depth);
314}
315EXPORT_SYMBOL(scsi_track_queue_full);
316
317/**
318 * scsi_vpd_inquiry - Request a device provide us with a VPD page
319 * @sdev: The device to ask
320 * @buffer: Where to put the result
321 * @page: Which Vital Product Data to return
322 * @len: The length of the buffer
323 *
324 * This is an internal helper function. You probably want to use
325 * scsi_get_vpd_page instead.
326 *
327 * Returns size of the vpd page on success or a negative error number.
328 */
329static int scsi_vpd_inquiry(struct scsi_device *sdev, unsigned char *buffer,
330 u8 page, unsigned len)
331{
332 int result;
333 unsigned char cmd[16];
334
335 if (len < 4)
336 return -EINVAL;
337
338 cmd[0] = INQUIRY;
339 cmd[1] = 1; /* EVPD */
340 cmd[2] = page;
341 cmd[3] = len >> 8;
342 cmd[4] = len & 0xff;
343 cmd[5] = 0; /* Control byte */
344
345 /*
346 * I'm not convinced we need to try quite this hard to get VPD, but
347 * all the existing users tried this hard.
348 */
349 result = scsi_execute_req(sdev, cmd, DMA_FROM_DEVICE, buffer,
350 len, NULL, 30 * HZ, 3, NULL);
351 if (result)
352 return -EIO;
353
354 /* Sanity check that we got the page back that we asked for */
355 if (buffer[1] != page)
356 return -EIO;
357
358 return get_unaligned_be16(&buffer[2]) + 4;
359}
360
361/**
362 * scsi_get_vpd_page - Get Vital Product Data from a SCSI device
363 * @sdev: The device to ask
364 * @page: Which Vital Product Data to return
365 * @buf: where to store the VPD
366 * @buf_len: number of bytes in the VPD buffer area
367 *
368 * SCSI devices may optionally supply Vital Product Data. Each 'page'
369 * of VPD is defined in the appropriate SCSI document (eg SPC, SBC).
370 * If the device supports this VPD page, this routine returns a pointer
371 * to a buffer containing the data from that page. The caller is
372 * responsible for calling kfree() on this pointer when it is no longer
373 * needed. If we cannot retrieve the VPD page this routine returns %NULL.
374 */
375int scsi_get_vpd_page(struct scsi_device *sdev, u8 page, unsigned char *buf,
376 int buf_len)
377{
378 int i, result;
379
380 if (sdev->skip_vpd_pages)
381 goto fail;
382
383 /* Ask for all the pages supported by this device */
384 result = scsi_vpd_inquiry(sdev, buf, 0, buf_len);
385 if (result < 4)
386 goto fail;
387
388 /* If the user actually wanted this page, we can skip the rest */
389 if (page == 0)
390 return 0;
391
392 for (i = 4; i < min(result, buf_len); i++)
393 if (buf[i] == page)
394 goto found;
395
396 if (i < result && i >= buf_len)
397 /* ran off the end of the buffer, give us benefit of doubt */
398 goto found;
399 /* The device claims it doesn't support the requested page */
400 goto fail;
401
402 found:
403 result = scsi_vpd_inquiry(sdev, buf, page, buf_len);
404 if (result < 0)
405 goto fail;
406
407 return 0;
408
409 fail:
410 return -EINVAL;
411}
412EXPORT_SYMBOL_GPL(scsi_get_vpd_page);
413
414/**
415 * scsi_get_vpd_buf - Get Vital Product Data from a SCSI device
416 * @sdev: The device to ask
417 * @page: Which Vital Product Data to return
418 *
419 * Returns %NULL upon failure.
420 */
421static struct scsi_vpd *scsi_get_vpd_buf(struct scsi_device *sdev, u8 page)
422{
423 struct scsi_vpd *vpd_buf;
424 int vpd_len = SCSI_VPD_PG_LEN, result;
425
426retry_pg:
427 vpd_buf = kmalloc(sizeof(*vpd_buf) + vpd_len, GFP_KERNEL);
428 if (!vpd_buf)
429 return NULL;
430
431 result = scsi_vpd_inquiry(sdev, vpd_buf->data, page, vpd_len);
432 if (result < 0) {
433 kfree(vpd_buf);
434 return NULL;
435 }
436 if (result > vpd_len) {
437 vpd_len = result;
438 kfree(vpd_buf);
439 goto retry_pg;
440 }
441
442 vpd_buf->len = result;
443
444 return vpd_buf;
445}
446
447static void scsi_update_vpd_page(struct scsi_device *sdev, u8 page,
448 struct scsi_vpd __rcu **sdev_vpd_buf)
449{
450 struct scsi_vpd *vpd_buf;
451
452 vpd_buf = scsi_get_vpd_buf(sdev, page);
453 if (!vpd_buf)
454 return;
455
456 mutex_lock(&sdev->inquiry_mutex);
457 rcu_swap_protected(*sdev_vpd_buf, vpd_buf,
458 lockdep_is_held(&sdev->inquiry_mutex));
459 mutex_unlock(&sdev->inquiry_mutex);
460
461 if (vpd_buf)
462 kfree_rcu(vpd_buf, rcu);
463}
464
465/**
466 * scsi_attach_vpd - Attach Vital Product Data to a SCSI device structure
467 * @sdev: The device to ask
468 *
469 * Attach the 'Device Identification' VPD page (0x83) and the
470 * 'Unit Serial Number' VPD page (0x80) to a SCSI device
471 * structure. This information can be used to identify the device
472 * uniquely.
473 */
474void scsi_attach_vpd(struct scsi_device *sdev)
475{
476 int i;
477 struct scsi_vpd *vpd_buf;
478
479 if (!scsi_device_supports_vpd(sdev))
480 return;
481
482 /* Ask for all the pages supported by this device */
483 vpd_buf = scsi_get_vpd_buf(sdev, 0);
484 if (!vpd_buf)
485 return;
486
487 for (i = 4; i < vpd_buf->len; i++) {
488 if (vpd_buf->data[i] == 0x80)
489 scsi_update_vpd_page(sdev, 0x80, &sdev->vpd_pg80);
490 if (vpd_buf->data[i] == 0x83)
491 scsi_update_vpd_page(sdev, 0x83, &sdev->vpd_pg83);
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;
513
514 if (sdev->no_report_opcodes || sdev->scsi_level < SCSI_SPC_3)
515 return -EINVAL;
516
517 memset(cmd, 0, 16);
518 cmd[0] = MAINTENANCE_IN;
519 cmd[1] = MI_REPORT_SUPPORTED_OPERATION_CODES;
520 cmd[2] = 1; /* One command format */
521 cmd[3] = opcode;
522 put_unaligned_be32(len, &cmd[6]);
523 memset(buffer, 0, len);
524
525 result = scsi_execute_req(sdev, cmd, DMA_FROM_DEVICE, buffer, len,
526 &sshdr, 30 * HZ, 3, NULL);
527
528 if (result && scsi_sense_valid(&sshdr) &&
529 sshdr.sense_key == ILLEGAL_REQUEST &&
530 (sshdr.asc == 0x20 || sshdr.asc == 0x24) && sshdr.ascq == 0x00)
531 return -EINVAL;
532
533 if ((buffer[1] & 3) == 3) /* Command supported */
534 return 1;
535
536 return 0;
537}
538EXPORT_SYMBOL(scsi_report_opcode);
539
540/**
541 * scsi_device_get - get an additional reference to a scsi_device
542 * @sdev: device to get a reference to
543 *
544 * Description: Gets a reference to the scsi_device and increments the use count
545 * of the underlying LLDD module. You must hold host_lock of the
546 * parent Scsi_Host or already have a reference when calling this.
547 *
548 * This will fail if a device is deleted or cancelled, or when the LLD module
549 * is in the process of being unloaded.
550 */
551int scsi_device_get(struct scsi_device *sdev)
552{
553 if (sdev->sdev_state == SDEV_DEL || sdev->sdev_state == SDEV_CANCEL)
554 goto fail;
555 if (!get_device(&sdev->sdev_gendev))
556 goto fail;
557 if (!try_module_get(sdev->host->hostt->module))
558 goto fail_put_device;
559 return 0;
560
561fail_put_device:
562 put_device(&sdev->sdev_gendev);
563fail:
564 return -ENXIO;
565}
566EXPORT_SYMBOL(scsi_device_get);
567
568/**
569 * scsi_device_put - release a reference to a scsi_device
570 * @sdev: device to release a reference on.
571 *
572 * Description: Release a reference to the scsi_device and decrements the use
573 * count of the underlying LLDD module. The device is freed once the last
574 * user vanishes.
575 */
576void scsi_device_put(struct scsi_device *sdev)
577{
578 module_put(sdev->host->hostt->module);
579 put_device(&sdev->sdev_gendev);
580}
581EXPORT_SYMBOL(scsi_device_put);
582
583/* helper for shost_for_each_device, see that for documentation */
584struct scsi_device *__scsi_iterate_devices(struct Scsi_Host *shost,
585 struct scsi_device *prev)
586{
587 struct list_head *list = (prev ? &prev->siblings : &shost->__devices);
588 struct scsi_device *next = NULL;
589 unsigned long flags;
590
591 spin_lock_irqsave(shost->host_lock, flags);
592 while (list->next != &shost->__devices) {
593 next = list_entry(list->next, struct scsi_device, siblings);
594 /* skip devices that we can't get a reference to */
595 if (!scsi_device_get(next))
596 break;
597 next = NULL;
598 list = list->next;
599 }
600 spin_unlock_irqrestore(shost->host_lock, flags);
601
602 if (prev)
603 scsi_device_put(prev);
604 return next;
605}
606EXPORT_SYMBOL(__scsi_iterate_devices);
607
608/**
609 * starget_for_each_device - helper to walk all devices of a target
610 * @starget: target whose devices we want to iterate over.
611 * @data: Opaque passed to each function call.
612 * @fn: Function to call on each device
613 *
614 * This traverses over each device of @starget. The devices have
615 * a reference that must be released by scsi_host_put when breaking
616 * out of the loop.
617 */
618void starget_for_each_device(struct scsi_target *starget, void *data,
619 void (*fn)(struct scsi_device *, void *))
620{
621 struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
622 struct scsi_device *sdev;
623
624 shost_for_each_device(sdev, shost) {
625 if ((sdev->channel == starget->channel) &&
626 (sdev->id == starget->id))
627 fn(sdev, data);
628 }
629}
630EXPORT_SYMBOL(starget_for_each_device);
631
632/**
633 * __starget_for_each_device - helper to walk all devices of a target (UNLOCKED)
634 * @starget: target whose devices we want to iterate over.
635 * @data: parameter for callback @fn()
636 * @fn: callback function that is invoked for each device
637 *
638 * This traverses over each device of @starget. It does _not_
639 * take a reference on the scsi_device, so the whole loop must be
640 * protected by shost->host_lock.
641 *
642 * Note: The only reason why drivers would want to use this is because
643 * they need to access the device list in irq context. Otherwise you
644 * really want to use starget_for_each_device instead.
645 **/
646void __starget_for_each_device(struct scsi_target *starget, void *data,
647 void (*fn)(struct scsi_device *, void *))
648{
649 struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
650 struct scsi_device *sdev;
651
652 __shost_for_each_device(sdev, shost) {
653 if ((sdev->channel == starget->channel) &&
654 (sdev->id == starget->id))
655 fn(sdev, data);
656 }
657}
658EXPORT_SYMBOL(__starget_for_each_device);
659
660/**
661 * __scsi_device_lookup_by_target - find a device given the target (UNLOCKED)
662 * @starget: SCSI target pointer
663 * @lun: SCSI Logical Unit Number
664 *
665 * Description: Looks up the scsi_device with the specified @lun for a given
666 * @starget. The returned scsi_device does not have an additional
667 * reference. You must hold the host's host_lock over this call and
668 * any access to the returned scsi_device. A scsi_device in state
669 * SDEV_DEL is skipped.
670 *
671 * Note: The only reason why drivers should use this is because
672 * they need to access the device list in irq context. Otherwise you
673 * really want to use scsi_device_lookup_by_target instead.
674 **/
675struct scsi_device *__scsi_device_lookup_by_target(struct scsi_target *starget,
676 u64 lun)
677{
678 struct scsi_device *sdev;
679
680 list_for_each_entry(sdev, &starget->devices, same_target_siblings) {
681 if (sdev->sdev_state == SDEV_DEL)
682 continue;
683 if (sdev->lun ==lun)
684 return sdev;
685 }
686
687 return NULL;
688}
689EXPORT_SYMBOL(__scsi_device_lookup_by_target);
690
691/**
692 * scsi_device_lookup_by_target - find a device given the target
693 * @starget: SCSI target pointer
694 * @lun: SCSI Logical Unit Number
695 *
696 * Description: Looks up the scsi_device with the specified @lun for a given
697 * @starget. The returned scsi_device has an additional reference that
698 * needs to be released with scsi_device_put once you're done with it.
699 **/
700struct scsi_device *scsi_device_lookup_by_target(struct scsi_target *starget,
701 u64 lun)
702{
703 struct scsi_device *sdev;
704 struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
705 unsigned long flags;
706
707 spin_lock_irqsave(shost->host_lock, flags);
708 sdev = __scsi_device_lookup_by_target(starget, lun);
709 if (sdev && scsi_device_get(sdev))
710 sdev = NULL;
711 spin_unlock_irqrestore(shost->host_lock, flags);
712
713 return sdev;
714}
715EXPORT_SYMBOL(scsi_device_lookup_by_target);
716
717/**
718 * __scsi_device_lookup - find a device given the host (UNLOCKED)
719 * @shost: SCSI host pointer
720 * @channel: SCSI channel (zero if only one channel)
721 * @id: SCSI target number (physical unit number)
722 * @lun: SCSI Logical Unit Number
723 *
724 * Description: Looks up the scsi_device with the specified @channel, @id, @lun
725 * for a given host. The returned scsi_device does not have an additional
726 * reference. You must hold the host's host_lock over this call and any access
727 * to the returned scsi_device.
728 *
729 * Note: The only reason why drivers would want to use this is because
730 * they need to access the device list in irq context. Otherwise you
731 * really want to use scsi_device_lookup instead.
732 **/
733struct scsi_device *__scsi_device_lookup(struct Scsi_Host *shost,
734 uint channel, uint id, u64 lun)
735{
736 struct scsi_device *sdev;
737
738 list_for_each_entry(sdev, &shost->__devices, siblings) {
739 if (sdev->sdev_state == SDEV_DEL)
740 continue;
741 if (sdev->channel == channel && sdev->id == id &&
742 sdev->lun ==lun)
743 return sdev;
744 }
745
746 return NULL;
747}
748EXPORT_SYMBOL(__scsi_device_lookup);
749
750/**
751 * scsi_device_lookup - find a device given the host
752 * @shost: SCSI host pointer
753 * @channel: SCSI channel (zero if only one channel)
754 * @id: SCSI target number (physical unit number)
755 * @lun: SCSI Logical Unit Number
756 *
757 * Description: Looks up the scsi_device with the specified @channel, @id, @lun
758 * for a given host. The returned scsi_device has an additional reference that
759 * needs to be released with scsi_device_put once you're done with it.
760 **/
761struct scsi_device *scsi_device_lookup(struct Scsi_Host *shost,
762 uint channel, uint id, u64 lun)
763{
764 struct scsi_device *sdev;
765 unsigned long flags;
766
767 spin_lock_irqsave(shost->host_lock, flags);
768 sdev = __scsi_device_lookup(shost, channel, id, lun);
769 if (sdev && scsi_device_get(sdev))
770 sdev = NULL;
771 spin_unlock_irqrestore(shost->host_lock, flags);
772
773 return sdev;
774}
775EXPORT_SYMBOL(scsi_device_lookup);
776
777MODULE_DESCRIPTION("SCSI core");
778MODULE_LICENSE("GPL");
779
780module_param(scsi_logging_level, int, S_IRUGO|S_IWUSR);
781MODULE_PARM_DESC(scsi_logging_level, "a bit mask of logging levels");
782
783#ifdef CONFIG_SCSI_MQ_DEFAULT
784bool scsi_use_blk_mq = true;
785#else
786bool scsi_use_blk_mq = false;
787#endif
788module_param_named(use_blk_mq, scsi_use_blk_mq, bool, S_IWUSR | S_IRUGO);
789
790static int __init init_scsi(void)
791{
792 int error;
793
794 error = scsi_init_queue();
795 if (error)
796 return error;
797 error = scsi_init_procfs();
798 if (error)
799 goto cleanup_queue;
800 error = scsi_init_devinfo();
801 if (error)
802 goto cleanup_procfs;
803 error = scsi_init_hosts();
804 if (error)
805 goto cleanup_devlist;
806 error = scsi_init_sysctl();
807 if (error)
808 goto cleanup_hosts;
809 error = scsi_sysfs_register();
810 if (error)
811 goto cleanup_sysctl;
812
813 scsi_netlink_init();
814
815 printk(KERN_NOTICE "SCSI subsystem initialized\n");
816 return 0;
817
818cleanup_sysctl:
819 scsi_exit_sysctl();
820cleanup_hosts:
821 scsi_exit_hosts();
822cleanup_devlist:
823 scsi_exit_devinfo();
824cleanup_procfs:
825 scsi_exit_procfs();
826cleanup_queue:
827 scsi_exit_queue();
828 printk(KERN_ERR "SCSI subsystem failed to initialize, error = %d\n",
829 -error);
830 return error;
831}
832
833static void __exit exit_scsi(void)
834{
835 scsi_netlink_exit();
836 scsi_sysfs_unregister();
837 scsi_exit_sysctl();
838 scsi_exit_hosts();
839 scsi_exit_devinfo();
840 scsi_exit_procfs();
841 scsi_exit_queue();
842 async_unregister_domain(&scsi_sd_probe_domain);
843}
844
845subsys_initcall(init_scsi);
846module_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 <linux/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_cmd(sdev, cmd, REQ_OP_DRV_IN, buffer, len,
313 30 * HZ, 3, NULL);
314 if (result)
315 return -EIO;
316
317 /*
318 * Sanity check that we got the page back that we asked for and that
319 * the page size is not 0.
320 */
321 if (buffer[1] != page)
322 return -EIO;
323
324 result = get_unaligned_be16(&buffer[2]);
325 if (!result)
326 return -EIO;
327
328 return result + 4;
329}
330
331enum scsi_vpd_parameters {
332 SCSI_VPD_HEADER_SIZE = 4,
333 SCSI_VPD_LIST_SIZE = 36,
334};
335
336static int scsi_get_vpd_size(struct scsi_device *sdev, u8 page)
337{
338 unsigned char vpd[SCSI_VPD_LIST_SIZE] __aligned(4);
339 int result;
340
341 if (sdev->no_vpd_size)
342 return SCSI_DEFAULT_VPD_LEN;
343
344 /*
345 * Fetch the supported pages VPD and validate that the requested page
346 * number is present.
347 */
348 if (page != 0) {
349 result = scsi_vpd_inquiry(sdev, vpd, 0, sizeof(vpd));
350 if (result < SCSI_VPD_HEADER_SIZE)
351 return 0;
352
353 if (result > sizeof(vpd)) {
354 dev_warn_once(&sdev->sdev_gendev,
355 "%s: long VPD page 0 length: %d bytes\n",
356 __func__, result);
357 result = sizeof(vpd);
358 }
359
360 result -= SCSI_VPD_HEADER_SIZE;
361 if (!memchr(&vpd[SCSI_VPD_HEADER_SIZE], page, result))
362 return 0;
363 }
364 /*
365 * Fetch the VPD page header to find out how big the page
366 * is. This is done to prevent problems on legacy devices
367 * which can not handle allocation lengths as large as
368 * potentially requested by the caller.
369 */
370 result = scsi_vpd_inquiry(sdev, vpd, page, SCSI_VPD_HEADER_SIZE);
371 if (result < 0)
372 return 0;
373
374 if (result < SCSI_VPD_HEADER_SIZE) {
375 dev_warn_once(&sdev->sdev_gendev,
376 "%s: short VPD page 0x%02x length: %d bytes\n",
377 __func__, page, result);
378 return 0;
379 }
380
381 return result;
382}
383
384/**
385 * scsi_get_vpd_page - Get Vital Product Data from a SCSI device
386 * @sdev: The device to ask
387 * @page: Which Vital Product Data to return
388 * @buf: where to store the VPD
389 * @buf_len: number of bytes in the VPD buffer area
390 *
391 * SCSI devices may optionally supply Vital Product Data. Each 'page'
392 * of VPD is defined in the appropriate SCSI document (eg SPC, SBC).
393 * If the device supports this VPD page, this routine fills @buf
394 * with the data from that page and return 0. If the VPD page is not
395 * supported or its content cannot be retrieved, -EINVAL is returned.
396 */
397int scsi_get_vpd_page(struct scsi_device *sdev, u8 page, unsigned char *buf,
398 int buf_len)
399{
400 int result, vpd_len;
401
402 if (!scsi_device_supports_vpd(sdev))
403 return -EINVAL;
404
405 vpd_len = scsi_get_vpd_size(sdev, page);
406 if (vpd_len <= 0)
407 return -EINVAL;
408
409 vpd_len = min(vpd_len, buf_len);
410
411 /*
412 * Fetch the actual page. Since the appropriate size was reported
413 * by the device it is now safe to ask for something bigger.
414 */
415 memset(buf, 0, buf_len);
416 result = scsi_vpd_inquiry(sdev, buf, page, vpd_len);
417 if (result < 0)
418 return -EINVAL;
419 else if (result > vpd_len)
420 dev_warn_once(&sdev->sdev_gendev,
421 "%s: VPD page 0x%02x result %d > %d bytes\n",
422 __func__, page, result, vpd_len);
423
424 return 0;
425}
426EXPORT_SYMBOL_GPL(scsi_get_vpd_page);
427
428/**
429 * scsi_get_vpd_buf - Get Vital Product Data from a SCSI device
430 * @sdev: The device to ask
431 * @page: Which Vital Product Data to return
432 *
433 * Returns %NULL upon failure.
434 */
435static struct scsi_vpd *scsi_get_vpd_buf(struct scsi_device *sdev, u8 page)
436{
437 struct scsi_vpd *vpd_buf;
438 int vpd_len, result;
439
440 vpd_len = scsi_get_vpd_size(sdev, page);
441 if (vpd_len <= 0)
442 return NULL;
443
444retry_pg:
445 /*
446 * Fetch the actual page. Since the appropriate size was reported
447 * by the device it is now safe to ask for something bigger.
448 */
449 vpd_buf = kmalloc(sizeof(*vpd_buf) + vpd_len, GFP_KERNEL);
450 if (!vpd_buf)
451 return NULL;
452
453 result = scsi_vpd_inquiry(sdev, vpd_buf->data, page, vpd_len);
454 if (result < 0) {
455 kfree(vpd_buf);
456 return NULL;
457 }
458 if (result > vpd_len) {
459 dev_warn_once(&sdev->sdev_gendev,
460 "%s: VPD page 0x%02x result %d > %d bytes\n",
461 __func__, page, result, vpd_len);
462 vpd_len = result;
463 kfree(vpd_buf);
464 goto retry_pg;
465 }
466
467 vpd_buf->len = result;
468
469 return vpd_buf;
470}
471
472static void scsi_update_vpd_page(struct scsi_device *sdev, u8 page,
473 struct scsi_vpd __rcu **sdev_vpd_buf)
474{
475 struct scsi_vpd *vpd_buf;
476
477 vpd_buf = scsi_get_vpd_buf(sdev, page);
478 if (!vpd_buf)
479 return;
480
481 mutex_lock(&sdev->inquiry_mutex);
482 vpd_buf = rcu_replace_pointer(*sdev_vpd_buf, vpd_buf,
483 lockdep_is_held(&sdev->inquiry_mutex));
484 mutex_unlock(&sdev->inquiry_mutex);
485
486 if (vpd_buf)
487 kfree_rcu(vpd_buf, rcu);
488}
489
490/**
491 * scsi_attach_vpd - Attach Vital Product Data to a SCSI device structure
492 * @sdev: The device to ask
493 *
494 * Attach the 'Device Identification' VPD page (0x83) and the
495 * 'Unit Serial Number' VPD page (0x80) to a SCSI device
496 * structure. This information can be used to identify the device
497 * uniquely.
498 */
499void scsi_attach_vpd(struct scsi_device *sdev)
500{
501 int i;
502 struct scsi_vpd *vpd_buf;
503
504 if (!scsi_device_supports_vpd(sdev))
505 return;
506
507 /* Ask for all the pages supported by this device */
508 vpd_buf = scsi_get_vpd_buf(sdev, 0);
509 if (!vpd_buf)
510 return;
511
512 for (i = 4; i < vpd_buf->len; i++) {
513 if (vpd_buf->data[i] == 0x0)
514 scsi_update_vpd_page(sdev, 0x0, &sdev->vpd_pg0);
515 if (vpd_buf->data[i] == 0x80)
516 scsi_update_vpd_page(sdev, 0x80, &sdev->vpd_pg80);
517 if (vpd_buf->data[i] == 0x83)
518 scsi_update_vpd_page(sdev, 0x83, &sdev->vpd_pg83);
519 if (vpd_buf->data[i] == 0x89)
520 scsi_update_vpd_page(sdev, 0x89, &sdev->vpd_pg89);
521 if (vpd_buf->data[i] == 0xb0)
522 scsi_update_vpd_page(sdev, 0xb0, &sdev->vpd_pgb0);
523 if (vpd_buf->data[i] == 0xb1)
524 scsi_update_vpd_page(sdev, 0xb1, &sdev->vpd_pgb1);
525 if (vpd_buf->data[i] == 0xb2)
526 scsi_update_vpd_page(sdev, 0xb2, &sdev->vpd_pgb2);
527 if (vpd_buf->data[i] == 0xb7)
528 scsi_update_vpd_page(sdev, 0xb7, &sdev->vpd_pgb7);
529 }
530 kfree(vpd_buf);
531}
532
533/**
534 * scsi_report_opcode - Find out if a given command is supported
535 * @sdev: scsi device to query
536 * @buffer: scratch buffer (must be at least 20 bytes long)
537 * @len: length of buffer
538 * @opcode: opcode for the command to look up
539 * @sa: service action for the command to look up
540 *
541 * Uses the REPORT SUPPORTED OPERATION CODES to check support for the
542 * command identified with @opcode and @sa. If the command does not
543 * have a service action, @sa must be 0. Returns -EINVAL if RSOC fails,
544 * 0 if the command is not supported and 1 if the device claims to
545 * support the command.
546 */
547int scsi_report_opcode(struct scsi_device *sdev, unsigned char *buffer,
548 unsigned int len, unsigned char opcode,
549 unsigned short sa)
550{
551 unsigned char cmd[16];
552 struct scsi_sense_hdr sshdr;
553 int result, request_len;
554 const struct scsi_exec_args exec_args = {
555 .sshdr = &sshdr,
556 };
557
558 if (sdev->no_report_opcodes || sdev->scsi_level < SCSI_SPC_3)
559 return -EINVAL;
560
561 /* RSOC header + size of command we are asking about */
562 request_len = 4 + COMMAND_SIZE(opcode);
563 if (request_len > len) {
564 dev_warn_once(&sdev->sdev_gendev,
565 "%s: len %u bytes, opcode 0x%02x needs %u\n",
566 __func__, len, opcode, request_len);
567 return -EINVAL;
568 }
569
570 memset(cmd, 0, 16);
571 cmd[0] = MAINTENANCE_IN;
572 cmd[1] = MI_REPORT_SUPPORTED_OPERATION_CODES;
573 if (!sa) {
574 cmd[2] = 1; /* One command format */
575 cmd[3] = opcode;
576 } else {
577 cmd[2] = 3; /* One command format with service action */
578 cmd[3] = opcode;
579 put_unaligned_be16(sa, &cmd[4]);
580 }
581 put_unaligned_be32(request_len, &cmd[6]);
582 memset(buffer, 0, len);
583
584 result = scsi_execute_cmd(sdev, cmd, REQ_OP_DRV_IN, buffer,
585 request_len, 30 * HZ, 3, &exec_args);
586 if (result < 0)
587 return result;
588 if (result && scsi_sense_valid(&sshdr) &&
589 sshdr.sense_key == ILLEGAL_REQUEST &&
590 (sshdr.asc == 0x20 || sshdr.asc == 0x24) && sshdr.ascq == 0x00)
591 return -EINVAL;
592
593 if ((buffer[1] & 3) == 3) /* Command supported */
594 return 1;
595
596 return 0;
597}
598EXPORT_SYMBOL(scsi_report_opcode);
599
600#define SCSI_CDL_CHECK_BUF_LEN 64
601
602static bool scsi_cdl_check_cmd(struct scsi_device *sdev, u8 opcode, u16 sa,
603 unsigned char *buf)
604{
605 int ret;
606 u8 cdlp;
607
608 /* Check operation code */
609 ret = scsi_report_opcode(sdev, buf, SCSI_CDL_CHECK_BUF_LEN, opcode, sa);
610 if (ret <= 0)
611 return false;
612
613 if ((buf[1] & 0x03) != 0x03)
614 return false;
615
616 /*
617 * See SPC-6, One_command parameter data format for
618 * REPORT SUPPORTED OPERATION CODES. We have the following cases
619 * depending on rwcdlp (buf[0] & 0x01) value:
620 * - rwcdlp == 0: then cdlp indicates support for the A mode page when
621 * it is equal to 1 and for the B mode page when it is
622 * equal to 2.
623 * - rwcdlp == 1: then cdlp indicates support for the T2A mode page
624 * when it is equal to 1 and for the T2B mode page when
625 * it is equal to 2.
626 * Overall, to detect support for command duration limits, we only need
627 * to check that cdlp is 1 or 2.
628 */
629 cdlp = (buf[1] & 0x18) >> 3;
630
631 return cdlp == 0x01 || cdlp == 0x02;
632}
633
634/**
635 * scsi_cdl_check - Check if a SCSI device supports Command Duration Limits
636 * @sdev: The device to check
637 */
638void scsi_cdl_check(struct scsi_device *sdev)
639{
640 bool cdl_supported;
641 unsigned char *buf;
642
643 /*
644 * Support for CDL was defined in SPC-5. Ignore devices reporting an
645 * lower SPC version. This also avoids problems with old drives choking
646 * on MAINTENANCE_IN / MI_REPORT_SUPPORTED_OPERATION_CODES with a
647 * service action specified, as done in scsi_cdl_check_cmd().
648 */
649 if (sdev->scsi_level < SCSI_SPC_5) {
650 sdev->cdl_supported = 0;
651 return;
652 }
653
654 buf = kmalloc(SCSI_CDL_CHECK_BUF_LEN, GFP_KERNEL);
655 if (!buf) {
656 sdev->cdl_supported = 0;
657 return;
658 }
659
660 /* Check support for READ_16, WRITE_16, READ_32 and WRITE_32 commands */
661 cdl_supported =
662 scsi_cdl_check_cmd(sdev, READ_16, 0, buf) ||
663 scsi_cdl_check_cmd(sdev, WRITE_16, 0, buf) ||
664 scsi_cdl_check_cmd(sdev, VARIABLE_LENGTH_CMD, READ_32, buf) ||
665 scsi_cdl_check_cmd(sdev, VARIABLE_LENGTH_CMD, WRITE_32, buf);
666 if (cdl_supported) {
667 /*
668 * We have CDL support: force the use of READ16/WRITE16.
669 * READ32 and WRITE32 will be used for devices that support
670 * the T10_PI_TYPE2_PROTECTION protection type.
671 */
672 sdev->use_16_for_rw = 1;
673 sdev->use_10_for_rw = 0;
674
675 sdev->cdl_supported = 1;
676
677 /*
678 * If the device supports CDL, make sure that the current drive
679 * feature status is consistent with the user controlled
680 * cdl_enable state.
681 */
682 scsi_cdl_enable(sdev, sdev->cdl_enable);
683 } else {
684 sdev->cdl_supported = 0;
685 }
686
687 kfree(buf);
688}
689
690/**
691 * scsi_cdl_enable - Enable or disable a SCSI device supports for Command
692 * Duration Limits
693 * @sdev: The target device
694 * @enable: the target state
695 */
696int scsi_cdl_enable(struct scsi_device *sdev, bool enable)
697{
698 struct scsi_mode_data data;
699 struct scsi_sense_hdr sshdr;
700 struct scsi_vpd *vpd;
701 bool is_ata = false;
702 char buf[64];
703 int ret;
704
705 if (!sdev->cdl_supported)
706 return -EOPNOTSUPP;
707
708 rcu_read_lock();
709 vpd = rcu_dereference(sdev->vpd_pg89);
710 if (vpd)
711 is_ata = true;
712 rcu_read_unlock();
713
714 /*
715 * For ATA devices, CDL needs to be enabled with a SET FEATURES command.
716 */
717 if (is_ata) {
718 char *buf_data;
719 int len;
720
721 ret = scsi_mode_sense(sdev, 0x08, 0x0a, 0xf2, buf, sizeof(buf),
722 5 * HZ, 3, &data, NULL);
723 if (ret)
724 return -EINVAL;
725
726 /* Enable CDL using the ATA feature page */
727 len = min_t(size_t, sizeof(buf),
728 data.length - data.header_length -
729 data.block_descriptor_length);
730 buf_data = buf + data.header_length +
731 data.block_descriptor_length;
732 if (enable)
733 buf_data[4] = 0x02;
734 else
735 buf_data[4] = 0;
736
737 ret = scsi_mode_select(sdev, 1, 0, buf_data, len, 5 * HZ, 3,
738 &data, &sshdr);
739 if (ret) {
740 if (ret > 0 && scsi_sense_valid(&sshdr))
741 scsi_print_sense_hdr(sdev,
742 dev_name(&sdev->sdev_gendev), &sshdr);
743 return ret;
744 }
745 }
746
747 sdev->cdl_enable = enable;
748
749 return 0;
750}
751
752/**
753 * scsi_device_get - get an additional reference to a scsi_device
754 * @sdev: device to get a reference to
755 *
756 * Description: Gets a reference to the scsi_device and increments the use count
757 * of the underlying LLDD module. You must hold host_lock of the
758 * parent Scsi_Host or already have a reference when calling this.
759 *
760 * This will fail if a device is deleted or cancelled, or when the LLD module
761 * is in the process of being unloaded.
762 */
763int scsi_device_get(struct scsi_device *sdev)
764{
765 if (sdev->sdev_state == SDEV_DEL || sdev->sdev_state == SDEV_CANCEL)
766 goto fail;
767 if (!try_module_get(sdev->host->hostt->module))
768 goto fail;
769 if (!get_device(&sdev->sdev_gendev))
770 goto fail_put_module;
771 return 0;
772
773fail_put_module:
774 module_put(sdev->host->hostt->module);
775fail:
776 return -ENXIO;
777}
778EXPORT_SYMBOL(scsi_device_get);
779
780/**
781 * scsi_device_put - release a reference to a scsi_device
782 * @sdev: device to release a reference on.
783 *
784 * Description: Release a reference to the scsi_device and decrements the use
785 * count of the underlying LLDD module. The device is freed once the last
786 * user vanishes.
787 */
788void scsi_device_put(struct scsi_device *sdev)
789{
790 struct module *mod = sdev->host->hostt->module;
791
792 put_device(&sdev->sdev_gendev);
793 module_put(mod);
794}
795EXPORT_SYMBOL(scsi_device_put);
796
797/* helper for shost_for_each_device, see that for documentation */
798struct scsi_device *__scsi_iterate_devices(struct Scsi_Host *shost,
799 struct scsi_device *prev)
800{
801 struct list_head *list = (prev ? &prev->siblings : &shost->__devices);
802 struct scsi_device *next = NULL;
803 unsigned long flags;
804
805 spin_lock_irqsave(shost->host_lock, flags);
806 while (list->next != &shost->__devices) {
807 next = list_entry(list->next, struct scsi_device, siblings);
808 /* skip devices that we can't get a reference to */
809 if (!scsi_device_get(next))
810 break;
811 next = NULL;
812 list = list->next;
813 }
814 spin_unlock_irqrestore(shost->host_lock, flags);
815
816 if (prev)
817 scsi_device_put(prev);
818 return next;
819}
820EXPORT_SYMBOL(__scsi_iterate_devices);
821
822/**
823 * starget_for_each_device - helper to walk all devices of a target
824 * @starget: target whose devices we want to iterate over.
825 * @data: Opaque passed to each function call.
826 * @fn: Function to call on each device
827 *
828 * This traverses over each device of @starget. The devices have
829 * a reference that must be released by scsi_host_put when breaking
830 * out of the loop.
831 */
832void starget_for_each_device(struct scsi_target *starget, void *data,
833 void (*fn)(struct scsi_device *, void *))
834{
835 struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
836 struct scsi_device *sdev;
837
838 shost_for_each_device(sdev, shost) {
839 if ((sdev->channel == starget->channel) &&
840 (sdev->id == starget->id))
841 fn(sdev, data);
842 }
843}
844EXPORT_SYMBOL(starget_for_each_device);
845
846/**
847 * __starget_for_each_device - helper to walk all devices of a target (UNLOCKED)
848 * @starget: target whose devices we want to iterate over.
849 * @data: parameter for callback @fn()
850 * @fn: callback function that is invoked for each device
851 *
852 * This traverses over each device of @starget. It does _not_
853 * take a reference on the scsi_device, so the whole loop must be
854 * protected by shost->host_lock.
855 *
856 * Note: The only reason why drivers would want to use this is because
857 * they need to access the device list in irq context. Otherwise you
858 * really want to use starget_for_each_device instead.
859 **/
860void __starget_for_each_device(struct scsi_target *starget, void *data,
861 void (*fn)(struct scsi_device *, void *))
862{
863 struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
864 struct scsi_device *sdev;
865
866 __shost_for_each_device(sdev, shost) {
867 if ((sdev->channel == starget->channel) &&
868 (sdev->id == starget->id))
869 fn(sdev, data);
870 }
871}
872EXPORT_SYMBOL(__starget_for_each_device);
873
874/**
875 * __scsi_device_lookup_by_target - find a device given the target (UNLOCKED)
876 * @starget: SCSI target pointer
877 * @lun: SCSI Logical Unit Number
878 *
879 * Description: Looks up the scsi_device with the specified @lun for a given
880 * @starget. The returned scsi_device does not have an additional
881 * reference. You must hold the host's host_lock over this call and
882 * any access to the returned scsi_device. A scsi_device in state
883 * SDEV_DEL is skipped.
884 *
885 * Note: The only reason why drivers should use this is because
886 * they need to access the device list in irq context. Otherwise you
887 * really want to use scsi_device_lookup_by_target instead.
888 **/
889struct scsi_device *__scsi_device_lookup_by_target(struct scsi_target *starget,
890 u64 lun)
891{
892 struct scsi_device *sdev;
893
894 list_for_each_entry(sdev, &starget->devices, same_target_siblings) {
895 if (sdev->sdev_state == SDEV_DEL)
896 continue;
897 if (sdev->lun ==lun)
898 return sdev;
899 }
900
901 return NULL;
902}
903EXPORT_SYMBOL(__scsi_device_lookup_by_target);
904
905/**
906 * scsi_device_lookup_by_target - find a device given the target
907 * @starget: SCSI target pointer
908 * @lun: SCSI Logical Unit Number
909 *
910 * Description: Looks up the scsi_device with the specified @lun for a given
911 * @starget. The returned scsi_device has an additional reference that
912 * needs to be released with scsi_device_put once you're done with it.
913 **/
914struct scsi_device *scsi_device_lookup_by_target(struct scsi_target *starget,
915 u64 lun)
916{
917 struct scsi_device *sdev;
918 struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
919 unsigned long flags;
920
921 spin_lock_irqsave(shost->host_lock, flags);
922 sdev = __scsi_device_lookup_by_target(starget, lun);
923 if (sdev && scsi_device_get(sdev))
924 sdev = NULL;
925 spin_unlock_irqrestore(shost->host_lock, flags);
926
927 return sdev;
928}
929EXPORT_SYMBOL(scsi_device_lookup_by_target);
930
931/**
932 * __scsi_device_lookup - find a device given the host (UNLOCKED)
933 * @shost: SCSI host pointer
934 * @channel: SCSI channel (zero if only one channel)
935 * @id: SCSI target number (physical unit number)
936 * @lun: SCSI Logical Unit Number
937 *
938 * Description: Looks up the scsi_device with the specified @channel, @id, @lun
939 * for a given host. The returned scsi_device does not have an additional
940 * reference. You must hold the host's host_lock over this call and any access
941 * to the returned scsi_device.
942 *
943 * Note: The only reason why drivers would want to use this is because
944 * they need to access the device list in irq context. Otherwise you
945 * really want to use scsi_device_lookup instead.
946 **/
947struct scsi_device *__scsi_device_lookup(struct Scsi_Host *shost,
948 uint channel, uint id, u64 lun)
949{
950 struct scsi_device *sdev;
951
952 list_for_each_entry(sdev, &shost->__devices, siblings) {
953 if (sdev->sdev_state == SDEV_DEL)
954 continue;
955 if (sdev->channel == channel && sdev->id == id &&
956 sdev->lun ==lun)
957 return sdev;
958 }
959
960 return NULL;
961}
962EXPORT_SYMBOL(__scsi_device_lookup);
963
964/**
965 * scsi_device_lookup - find a device given the host
966 * @shost: SCSI host pointer
967 * @channel: SCSI channel (zero if only one channel)
968 * @id: SCSI target number (physical unit number)
969 * @lun: SCSI Logical Unit Number
970 *
971 * Description: Looks up the scsi_device with the specified @channel, @id, @lun
972 * for a given host. The returned scsi_device has an additional reference that
973 * needs to be released with scsi_device_put once you're done with it.
974 **/
975struct scsi_device *scsi_device_lookup(struct Scsi_Host *shost,
976 uint channel, uint id, u64 lun)
977{
978 struct scsi_device *sdev;
979 unsigned long flags;
980
981 spin_lock_irqsave(shost->host_lock, flags);
982 sdev = __scsi_device_lookup(shost, channel, id, lun);
983 if (sdev && scsi_device_get(sdev))
984 sdev = NULL;
985 spin_unlock_irqrestore(shost->host_lock, flags);
986
987 return sdev;
988}
989EXPORT_SYMBOL(scsi_device_lookup);
990
991MODULE_DESCRIPTION("SCSI core");
992MODULE_LICENSE("GPL");
993
994module_param(scsi_logging_level, int, S_IRUGO|S_IWUSR);
995MODULE_PARM_DESC(scsi_logging_level, "a bit mask of logging levels");
996
997static int __init init_scsi(void)
998{
999 int error;
1000
1001 error = scsi_init_procfs();
1002 if (error)
1003 goto cleanup_queue;
1004 error = scsi_init_devinfo();
1005 if (error)
1006 goto cleanup_procfs;
1007 error = scsi_init_hosts();
1008 if (error)
1009 goto cleanup_devlist;
1010 error = scsi_init_sysctl();
1011 if (error)
1012 goto cleanup_hosts;
1013 error = scsi_sysfs_register();
1014 if (error)
1015 goto cleanup_sysctl;
1016
1017 scsi_netlink_init();
1018
1019 printk(KERN_NOTICE "SCSI subsystem initialized\n");
1020 return 0;
1021
1022cleanup_sysctl:
1023 scsi_exit_sysctl();
1024cleanup_hosts:
1025 scsi_exit_hosts();
1026cleanup_devlist:
1027 scsi_exit_devinfo();
1028cleanup_procfs:
1029 scsi_exit_procfs();
1030cleanup_queue:
1031 scsi_exit_queue();
1032 printk(KERN_ERR "SCSI subsystem failed to initialize, error = %d\n",
1033 -error);
1034 return error;
1035}
1036
1037static void __exit exit_scsi(void)
1038{
1039 scsi_netlink_exit();
1040 scsi_sysfs_unregister();
1041 scsi_exit_sysctl();
1042 scsi_exit_hosts();
1043 scsi_exit_devinfo();
1044 scsi_exit_procfs();
1045 scsi_exit_queue();
1046}
1047
1048subsys_initcall(init_scsi);
1049module_exit(exit_scsi);