1 // SPDX-License-Identifier: GPL-2.0-only
3 * scsi.c Copyright (C) 1992 Drew Eckhardt
4 * Copyright (C) 1993, 1994, 1995, 1999 Eric Youngdale
5 * Copyright (C) 2002, 2003 Christoph Hellwig
7 * generic mid-level SCSI driver
8 * Initial versions: Drew Eckhardt
9 * Subsequent revisions: Eric Youngdale
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>
18 * Modified by Eric Youngdale eric@andante.org or ericy@gnu.ai.mit.edu to
19 * add scatter-gather, multiple outstanding request, and other
22 * Native multichannel, wide scsi, /proc/scsi and hot plugging
23 * support added by Michael Neuffer <mike@i-connect.net>
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>
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>
34 * Converted cli() code to spinlocks, Ingo Molnar
36 * Jiffies wrap fixes (host->resetting), 3 Dec 1998 Andrea Arcangeli
38 * out_of_space hacks, D. Gilbert (dpg) 990608
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>
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>
70 #include "scsi_priv.h"
71 #include "scsi_logging.h"
73 #define CREATE_TRACE_POINTS
74 #include <trace/events/scsi.h>
77 * Definitions and constants.
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.
84 unsigned int scsi_logging_level;
85 #if defined(CONFIG_SCSI_LOGGING)
86 EXPORT_SYMBOL(scsi_logging_level);
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
94 ASYNC_DOMAIN_EXCLUSIVE(scsi_sd_pm_domain);
95 EXPORT_SYMBOL(scsi_sd_pm_domain);
97 #ifdef CONFIG_SCSI_LOGGING
98 void scsi_log_send(struct scsi_cmnd *cmd)
103 * If ML QUEUE log level is greater than or equal to:
105 * 1: nothing (match completion)
107 * 2: log opcode + command of all commands + cmd address
113 if (unlikely(scsi_logging_level)) {
114 level = SCSI_LOG_LEVEL(SCSI_LOG_MLQUEUE_SHIFT,
115 SCSI_LOG_MLQUEUE_BITS);
117 scmd_printk(KERN_INFO, cmd,
118 "Send: scmd 0x%p\n", cmd);
119 scsi_print_command(cmd);
124 void scsi_log_completion(struct scsi_cmnd *cmd, int disposition)
129 * If ML COMPLETE log level is greater than or equal to:
131 * 1: log disposition, result, opcode + command, and conditionally
132 * sense data for failures or non SUCCESS dispositions.
134 * 2: same as 1 but for all command completions.
138 * 4: same as 3 plus dump extra junk
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)) ||
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);
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);
160 * scsi_finish_command - cleanup and pass command back to upper layer
163 * Description: Pass command off to upper layer for finishing of I/O
164 * request, waking processes that are waiting on results,
167 void scsi_finish_command(struct scsi_cmnd *cmd)
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;
175 scsi_device_unbusy(sdev, cmd);
178 * Clear the flags that say that the device/target/host is no longer
179 * capable of accepting new commands.
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);
188 SCSI_LOG_MLCOMPLETE(4, sdev_printk(KERN_INFO, sdev,
189 "Notifying upper driver of completion "
190 "(result %x)\n", cmd->result));
192 good_bytes = scsi_bufflen(cmd);
193 if (!blk_rq_is_passthrough(scsi_cmd_to_rq(cmd))) {
194 int old_good_bytes = good_bytes;
195 drv = scsi_cmd_to_driver(cmd);
197 good_bytes = drv->done(cmd);
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.
204 if (good_bytes == old_good_bytes)
205 good_bytes -= scsi_get_resid(cmd);
207 scsi_io_completion(cmd, good_bytes);
212 * 1024 is big enough for saturating the fast scsi LUN now
214 int scsi_device_max_queue_depth(struct scsi_device *sdev)
216 return max_t(int, sdev->host->can_queue, 1024);
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
224 * Sets the device queue depth and returns the new value.
226 int scsi_change_queue_depth(struct scsi_device *sdev, int depth)
228 depth = min_t(int, depth, scsi_device_max_queue_depth(sdev));
231 sdev->queue_depth = depth;
235 if (sdev->request_queue)
236 blk_set_queue_depth(sdev->request_queue, depth);
238 sbitmap_resize(&sdev->budget_map, sdev->queue_depth);
240 return sdev->queue_depth;
242 EXPORT_SYMBOL(scsi_change_queue_depth);
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.
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.
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
258 * Lock Status: None held on entry
260 * Notes: Low level drivers may call this at any time and we will do
261 * "The Right Thing." We are interrupt context safe.
263 int scsi_track_queue_full(struct scsi_device *sdev, int depth)
267 * Don't let QUEUE_FULLs on the same
268 * jiffies count, they could all be from
271 if ((jiffies >> 4) == (sdev->last_queue_full_time >> 4))
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;
279 sdev->last_queue_full_count++;
282 if (sdev->last_queue_full_count <= 10)
285 return scsi_change_queue_depth(sdev, depth);
287 EXPORT_SYMBOL(scsi_track_queue_full);
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
296 * This is an internal helper function. You probably want to use
297 * scsi_get_vpd_page instead.
299 * Returns size of the vpd page on success or a negative error number.
301 static int scsi_vpd_inquiry(struct scsi_device *sdev, unsigned char *buffer,
302 u8 page, unsigned len)
305 unsigned char cmd[16];
311 cmd[1] = 1; /* EVPD */
315 cmd[5] = 0; /* Control byte */
318 * I'm not convinced we need to try quite this hard to get VPD, but
319 * all the existing users tried this hard.
321 result = scsi_execute_req(sdev, cmd, DMA_FROM_DEVICE, buffer,
322 len, NULL, 30 * HZ, 3, NULL);
326 /* Sanity check that we got the page back that we asked for */
327 if (buffer[1] != page)
330 return get_unaligned_be16(&buffer[2]) + 4;
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
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.
347 int scsi_get_vpd_page(struct scsi_device *sdev, u8 page, unsigned char *buf,
352 if (sdev->skip_vpd_pages)
355 /* Ask for all the pages supported by this device */
356 result = scsi_vpd_inquiry(sdev, buf, 0, buf_len);
360 /* If the user actually wanted this page, we can skip the rest */
364 for (i = 4; i < min(result, buf_len); i++)
368 if (i < result && i >= buf_len)
369 /* ran off the end of the buffer, give us benefit of doubt */
371 /* The device claims it doesn't support the requested page */
375 result = scsi_vpd_inquiry(sdev, buf, page, buf_len);
384 EXPORT_SYMBOL_GPL(scsi_get_vpd_page);
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
391 * Returns %NULL upon failure.
393 static struct scsi_vpd *scsi_get_vpd_buf(struct scsi_device *sdev, u8 page)
395 struct scsi_vpd *vpd_buf;
396 int vpd_len = SCSI_VPD_PG_LEN, result;
399 vpd_buf = kmalloc(sizeof(*vpd_buf) + vpd_len, GFP_KERNEL);
403 result = scsi_vpd_inquiry(sdev, vpd_buf->data, page, vpd_len);
408 if (result > vpd_len) {
414 vpd_buf->len = result;
419 static void scsi_update_vpd_page(struct scsi_device *sdev, u8 page,
420 struct scsi_vpd __rcu **sdev_vpd_buf)
422 struct scsi_vpd *vpd_buf;
424 vpd_buf = scsi_get_vpd_buf(sdev, page);
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);
434 kfree_rcu(vpd_buf, rcu);
438 * scsi_attach_vpd - Attach Vital Product Data to a SCSI device structure
439 * @sdev: The device to ask
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
446 void scsi_attach_vpd(struct scsi_device *sdev)
449 struct scsi_vpd *vpd_buf;
451 if (!scsi_device_supports_vpd(sdev))
454 /* Ask for all the pages supported by this device */
455 vpd_buf = scsi_get_vpd_buf(sdev, 0);
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);
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
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.
483 int scsi_report_opcode(struct scsi_device *sdev, unsigned char *buffer,
484 unsigned int len, unsigned char opcode)
486 unsigned char cmd[16];
487 struct scsi_sense_hdr sshdr;
490 if (sdev->no_report_opcodes || sdev->scsi_level < SCSI_SPC_3)
494 cmd[0] = MAINTENANCE_IN;
495 cmd[1] = MI_REPORT_SUPPORTED_OPERATION_CODES;
496 cmd[2] = 1; /* One command format */
498 put_unaligned_be32(len, &cmd[6]);
499 memset(buffer, 0, len);
501 result = scsi_execute_req(sdev, cmd, DMA_FROM_DEVICE, buffer, len,
502 &sshdr, 30 * HZ, 3, NULL);
506 if (result && scsi_sense_valid(&sshdr) &&
507 sshdr.sense_key == ILLEGAL_REQUEST &&
508 (sshdr.asc == 0x20 || sshdr.asc == 0x24) && sshdr.ascq == 0x00)
511 if ((buffer[1] & 3) == 3) /* Command supported */
516 EXPORT_SYMBOL(scsi_report_opcode);
519 * scsi_device_get - get an additional reference to a scsi_device
520 * @sdev: device to get a reference to
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.
526 * This will fail if a device is deleted or cancelled, or when the LLD module
527 * is in the process of being unloaded.
529 int scsi_device_get(struct scsi_device *sdev)
531 if (sdev->sdev_state == SDEV_DEL || sdev->sdev_state == SDEV_CANCEL)
533 if (!get_device(&sdev->sdev_gendev))
535 if (!try_module_get(sdev->host->hostt->module))
536 goto fail_put_device;
540 put_device(&sdev->sdev_gendev);
544 EXPORT_SYMBOL(scsi_device_get);
547 * scsi_device_put - release a reference to a scsi_device
548 * @sdev: device to release a reference on.
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
554 void scsi_device_put(struct scsi_device *sdev)
556 module_put(sdev->host->hostt->module);
557 put_device(&sdev->sdev_gendev);
559 EXPORT_SYMBOL(scsi_device_put);
561 /* helper for shost_for_each_device, see that for documentation */
562 struct scsi_device *__scsi_iterate_devices(struct Scsi_Host *shost,
563 struct scsi_device *prev)
565 struct list_head *list = (prev ? &prev->siblings : &shost->__devices);
566 struct scsi_device *next = NULL;
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))
578 spin_unlock_irqrestore(shost->host_lock, flags);
581 scsi_device_put(prev);
584 EXPORT_SYMBOL(__scsi_iterate_devices);
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
592 * This traverses over each device of @starget. The devices have
593 * a reference that must be released by scsi_host_put when breaking
596 void starget_for_each_device(struct scsi_target *starget, void *data,
597 void (*fn)(struct scsi_device *, void *))
599 struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
600 struct scsi_device *sdev;
602 shost_for_each_device(sdev, shost) {
603 if ((sdev->channel == starget->channel) &&
604 (sdev->id == starget->id))
608 EXPORT_SYMBOL(starget_for_each_device);
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
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.
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.
624 void __starget_for_each_device(struct scsi_target *starget, void *data,
625 void (*fn)(struct scsi_device *, void *))
627 struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
628 struct scsi_device *sdev;
630 __shost_for_each_device(sdev, shost) {
631 if ((sdev->channel == starget->channel) &&
632 (sdev->id == starget->id))
636 EXPORT_SYMBOL(__starget_for_each_device);
639 * __scsi_device_lookup_by_target - find a device given the target (UNLOCKED)
640 * @starget: SCSI target pointer
641 * @lun: SCSI Logical Unit Number
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.
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.
653 struct scsi_device *__scsi_device_lookup_by_target(struct scsi_target *starget,
656 struct scsi_device *sdev;
658 list_for_each_entry(sdev, &starget->devices, same_target_siblings) {
659 if (sdev->sdev_state == SDEV_DEL)
667 EXPORT_SYMBOL(__scsi_device_lookup_by_target);
670 * scsi_device_lookup_by_target - find a device given the target
671 * @starget: SCSI target pointer
672 * @lun: SCSI Logical Unit Number
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.
678 struct scsi_device *scsi_device_lookup_by_target(struct scsi_target *starget,
681 struct scsi_device *sdev;
682 struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
685 spin_lock_irqsave(shost->host_lock, flags);
686 sdev = __scsi_device_lookup_by_target(starget, lun);
687 if (sdev && scsi_device_get(sdev))
689 spin_unlock_irqrestore(shost->host_lock, flags);
693 EXPORT_SYMBOL(scsi_device_lookup_by_target);
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
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.
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.
711 struct scsi_device *__scsi_device_lookup(struct Scsi_Host *shost,
712 uint channel, uint id, u64 lun)
714 struct scsi_device *sdev;
716 list_for_each_entry(sdev, &shost->__devices, siblings) {
717 if (sdev->sdev_state == SDEV_DEL)
719 if (sdev->channel == channel && sdev->id == id &&
726 EXPORT_SYMBOL(__scsi_device_lookup);
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
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.
739 struct scsi_device *scsi_device_lookup(struct Scsi_Host *shost,
740 uint channel, uint id, u64 lun)
742 struct scsi_device *sdev;
745 spin_lock_irqsave(shost->host_lock, flags);
746 sdev = __scsi_device_lookup(shost, channel, id, lun);
747 if (sdev && scsi_device_get(sdev))
749 spin_unlock_irqrestore(shost->host_lock, flags);
753 EXPORT_SYMBOL(scsi_device_lookup);
755 MODULE_DESCRIPTION("SCSI core");
756 MODULE_LICENSE("GPL");
758 module_param(scsi_logging_level, int, S_IRUGO|S_IWUSR);
759 MODULE_PARM_DESC(scsi_logging_level, "a bit mask of logging levels");
761 static int __init init_scsi(void)
765 error = scsi_init_procfs();
768 error = scsi_init_devinfo();
771 error = scsi_init_hosts();
773 goto cleanup_devlist;
774 error = scsi_init_sysctl();
777 error = scsi_sysfs_register();
783 printk(KERN_NOTICE "SCSI subsystem initialized\n");
796 printk(KERN_ERR "SCSI subsystem failed to initialize, error = %d\n",
801 static void __exit exit_scsi(void)
804 scsi_sysfs_unregister();
812 subsys_initcall(init_scsi);
813 module_exit(exit_scsi);