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 <asm/unaligned.h>
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>
69 #include "scsi_priv.h"
70 #include "scsi_logging.h"
72 #define CREATE_TRACE_POINTS
73 #include <trace/events/scsi.h>
76 * Definitions and constants.
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.
83 unsigned int scsi_logging_level;
84 #if defined(CONFIG_SCSI_LOGGING)
85 EXPORT_SYMBOL(scsi_logging_level);
88 #ifdef CONFIG_SCSI_LOGGING
89 void scsi_log_send(struct scsi_cmnd *cmd)
94 * If ML QUEUE log level is greater than or equal to:
96 * 1: nothing (match completion)
98 * 2: log opcode + command of all commands + cmd address
104 if (unlikely(scsi_logging_level)) {
105 level = SCSI_LOG_LEVEL(SCSI_LOG_MLQUEUE_SHIFT,
106 SCSI_LOG_MLQUEUE_BITS);
108 scmd_printk(KERN_INFO, cmd,
109 "Send: scmd 0x%p\n", cmd);
110 scsi_print_command(cmd);
115 void scsi_log_completion(struct scsi_cmnd *cmd, int disposition)
120 * If ML COMPLETE log level is greater than or equal to:
122 * 1: log disposition, result, opcode + command, and conditionally
123 * sense data for failures or non SUCCESS dispositions.
125 * 2: same as 1 but for all command completions.
129 * 4: same as 3 plus dump extra junk
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)) ||
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);
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);
151 * scsi_finish_command - cleanup and pass command back to upper layer
154 * Description: Pass command off to upper layer for finishing of I/O
155 * request, waking processes that are waiting on results,
158 void scsi_finish_command(struct scsi_cmnd *cmd)
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;
166 scsi_device_unbusy(sdev, cmd);
169 * Clear the flags that say that the device/target/host is no longer
170 * capable of accepting new commands.
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);
179 SCSI_LOG_MLCOMPLETE(4, sdev_printk(KERN_INFO, sdev,
180 "Notifying upper driver of completion "
181 "(result %x)\n", cmd->result));
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);
188 good_bytes = drv->done(cmd);
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.
195 if (good_bytes == old_good_bytes)
196 good_bytes -= scsi_get_resid(cmd);
198 scsi_io_completion(cmd, good_bytes);
203 * 4096 is big enough for saturating fast SCSI LUNs.
205 int scsi_device_max_queue_depth(struct scsi_device *sdev)
207 return min_t(int, sdev->host->can_queue, 4096);
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
215 * Sets the device queue depth and returns the new value.
217 int scsi_change_queue_depth(struct scsi_device *sdev, int depth)
219 depth = min_t(int, depth, scsi_device_max_queue_depth(sdev));
222 sdev->queue_depth = depth;
226 if (sdev->request_queue)
227 blk_set_queue_depth(sdev->request_queue, depth);
229 sbitmap_resize(&sdev->budget_map, sdev->queue_depth);
231 return sdev->queue_depth;
233 EXPORT_SYMBOL(scsi_change_queue_depth);
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.
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.
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
249 * Lock Status: None held on entry
251 * Notes: Low level drivers may call this at any time and we will do
252 * "The Right Thing." We are interrupt context safe.
254 int scsi_track_queue_full(struct scsi_device *sdev, int depth)
258 * Don't let QUEUE_FULLs on the same
259 * jiffies count, they could all be from
262 if ((jiffies >> 4) == (sdev->last_queue_full_time >> 4))
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;
270 sdev->last_queue_full_count++;
273 if (sdev->last_queue_full_count <= 10)
276 return scsi_change_queue_depth(sdev, depth);
278 EXPORT_SYMBOL(scsi_track_queue_full);
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
287 * This is an internal helper function. You probably want to use
288 * scsi_get_vpd_page instead.
290 * Returns size of the vpd page on success or a negative error number.
292 static int scsi_vpd_inquiry(struct scsi_device *sdev, unsigned char *buffer,
293 u8 page, unsigned len)
296 unsigned char cmd[16];
302 cmd[1] = 1; /* EVPD */
306 cmd[5] = 0; /* Control byte */
309 * I'm not convinced we need to try quite this hard to get VPD, but
310 * all the existing users tried this hard.
312 result = scsi_execute_cmd(sdev, cmd, REQ_OP_DRV_IN, buffer, len,
318 * Sanity check that we got the page back that we asked for and that
319 * the page size is not 0.
321 if (buffer[1] != page)
324 result = get_unaligned_be16(&buffer[2]);
331 enum scsi_vpd_parameters {
332 SCSI_VPD_HEADER_SIZE = 4,
333 SCSI_VPD_LIST_SIZE = 36,
336 static int scsi_get_vpd_size(struct scsi_device *sdev, u8 page)
338 unsigned char vpd[SCSI_VPD_LIST_SIZE] __aligned(4);
341 if (sdev->no_vpd_size)
342 return SCSI_DEFAULT_VPD_LEN;
345 * Fetch the supported pages VPD and validate that the requested page
349 result = scsi_vpd_inquiry(sdev, vpd, 0, sizeof(vpd));
350 if (result < SCSI_VPD_HEADER_SIZE)
353 result -= SCSI_VPD_HEADER_SIZE;
354 if (!memchr(&vpd[SCSI_VPD_HEADER_SIZE], page, result))
358 * Fetch the VPD page header to find out how big the page
359 * is. This is done to prevent problems on legacy devices
360 * which can not handle allocation lengths as large as
361 * potentially requested by the caller.
363 result = scsi_vpd_inquiry(sdev, vpd, page, SCSI_VPD_HEADER_SIZE);
367 if (result < SCSI_VPD_HEADER_SIZE) {
368 dev_warn_once(&sdev->sdev_gendev,
369 "%s: short VPD page 0x%02x length: %d bytes\n",
370 __func__, page, result);
378 * scsi_get_vpd_page - Get Vital Product Data from a SCSI device
379 * @sdev: The device to ask
380 * @page: Which Vital Product Data to return
381 * @buf: where to store the VPD
382 * @buf_len: number of bytes in the VPD buffer area
384 * SCSI devices may optionally supply Vital Product Data. Each 'page'
385 * of VPD is defined in the appropriate SCSI document (eg SPC, SBC).
386 * If the device supports this VPD page, this routine fills @buf
387 * with the data from that page and return 0. If the VPD page is not
388 * supported or its content cannot be retrieved, -EINVAL is returned.
390 int scsi_get_vpd_page(struct scsi_device *sdev, u8 page, unsigned char *buf,
395 if (!scsi_device_supports_vpd(sdev))
398 vpd_len = scsi_get_vpd_size(sdev, page);
402 vpd_len = min(vpd_len, buf_len);
405 * Fetch the actual page. Since the appropriate size was reported
406 * by the device it is now safe to ask for something bigger.
408 memset(buf, 0, buf_len);
409 result = scsi_vpd_inquiry(sdev, buf, page, vpd_len);
412 else if (result > vpd_len)
413 dev_warn_once(&sdev->sdev_gendev,
414 "%s: VPD page 0x%02x result %d > %d bytes\n",
415 __func__, page, result, vpd_len);
419 EXPORT_SYMBOL_GPL(scsi_get_vpd_page);
422 * scsi_get_vpd_buf - Get Vital Product Data from a SCSI device
423 * @sdev: The device to ask
424 * @page: Which Vital Product Data to return
426 * Returns %NULL upon failure.
428 static struct scsi_vpd *scsi_get_vpd_buf(struct scsi_device *sdev, u8 page)
430 struct scsi_vpd *vpd_buf;
433 vpd_len = scsi_get_vpd_size(sdev, page);
439 * Fetch the actual page. Since the appropriate size was reported
440 * by the device it is now safe to ask for something bigger.
442 vpd_buf = kmalloc(sizeof(*vpd_buf) + vpd_len, GFP_KERNEL);
446 result = scsi_vpd_inquiry(sdev, vpd_buf->data, page, vpd_len);
451 if (result > vpd_len) {
452 dev_warn_once(&sdev->sdev_gendev,
453 "%s: VPD page 0x%02x result %d > %d bytes\n",
454 __func__, page, result, vpd_len);
460 vpd_buf->len = result;
465 static void scsi_update_vpd_page(struct scsi_device *sdev, u8 page,
466 struct scsi_vpd __rcu **sdev_vpd_buf)
468 struct scsi_vpd *vpd_buf;
470 vpd_buf = scsi_get_vpd_buf(sdev, page);
474 mutex_lock(&sdev->inquiry_mutex);
475 vpd_buf = rcu_replace_pointer(*sdev_vpd_buf, vpd_buf,
476 lockdep_is_held(&sdev->inquiry_mutex));
477 mutex_unlock(&sdev->inquiry_mutex);
480 kfree_rcu(vpd_buf, rcu);
484 * scsi_attach_vpd - Attach Vital Product Data to a SCSI device structure
485 * @sdev: The device to ask
487 * Attach the 'Device Identification' VPD page (0x83) and the
488 * 'Unit Serial Number' VPD page (0x80) to a SCSI device
489 * structure. This information can be used to identify the device
492 void scsi_attach_vpd(struct scsi_device *sdev)
495 struct scsi_vpd *vpd_buf;
497 if (!scsi_device_supports_vpd(sdev))
500 /* Ask for all the pages supported by this device */
501 vpd_buf = scsi_get_vpd_buf(sdev, 0);
505 for (i = 4; i < vpd_buf->len; i++) {
506 if (vpd_buf->data[i] == 0x0)
507 scsi_update_vpd_page(sdev, 0x0, &sdev->vpd_pg0);
508 if (vpd_buf->data[i] == 0x80)
509 scsi_update_vpd_page(sdev, 0x80, &sdev->vpd_pg80);
510 if (vpd_buf->data[i] == 0x83)
511 scsi_update_vpd_page(sdev, 0x83, &sdev->vpd_pg83);
512 if (vpd_buf->data[i] == 0x89)
513 scsi_update_vpd_page(sdev, 0x89, &sdev->vpd_pg89);
514 if (vpd_buf->data[i] == 0xb0)
515 scsi_update_vpd_page(sdev, 0xb0, &sdev->vpd_pgb0);
516 if (vpd_buf->data[i] == 0xb1)
517 scsi_update_vpd_page(sdev, 0xb1, &sdev->vpd_pgb1);
518 if (vpd_buf->data[i] == 0xb2)
519 scsi_update_vpd_page(sdev, 0xb2, &sdev->vpd_pgb2);
525 * scsi_report_opcode - Find out if a given command is supported
526 * @sdev: scsi device to query
527 * @buffer: scratch buffer (must be at least 20 bytes long)
528 * @len: length of buffer
529 * @opcode: opcode for the command to look up
530 * @sa: service action for the command to look up
532 * Uses the REPORT SUPPORTED OPERATION CODES to check support for the
533 * command identified with @opcode and @sa. If the command does not
534 * have a service action, @sa must be 0. Returns -EINVAL if RSOC fails,
535 * 0 if the command is not supported and 1 if the device claims to
536 * support the command.
538 int scsi_report_opcode(struct scsi_device *sdev, unsigned char *buffer,
539 unsigned int len, unsigned char opcode,
542 unsigned char cmd[16];
543 struct scsi_sense_hdr sshdr;
544 int result, request_len;
545 const struct scsi_exec_args exec_args = {
549 if (sdev->no_report_opcodes || sdev->scsi_level < SCSI_SPC_3)
552 /* RSOC header + size of command we are asking about */
553 request_len = 4 + COMMAND_SIZE(opcode);
554 if (request_len > len) {
555 dev_warn_once(&sdev->sdev_gendev,
556 "%s: len %u bytes, opcode 0x%02x needs %u\n",
557 __func__, len, opcode, request_len);
562 cmd[0] = MAINTENANCE_IN;
563 cmd[1] = MI_REPORT_SUPPORTED_OPERATION_CODES;
565 cmd[2] = 1; /* One command format */
568 cmd[2] = 3; /* One command format with service action */
570 put_unaligned_be16(sa, &cmd[4]);
572 put_unaligned_be32(request_len, &cmd[6]);
573 memset(buffer, 0, len);
575 result = scsi_execute_cmd(sdev, cmd, REQ_OP_DRV_IN, buffer,
576 request_len, 30 * HZ, 3, &exec_args);
579 if (result && scsi_sense_valid(&sshdr) &&
580 sshdr.sense_key == ILLEGAL_REQUEST &&
581 (sshdr.asc == 0x20 || sshdr.asc == 0x24) && sshdr.ascq == 0x00)
584 if ((buffer[1] & 3) == 3) /* Command supported */
589 EXPORT_SYMBOL(scsi_report_opcode);
591 #define SCSI_CDL_CHECK_BUF_LEN 64
593 static bool scsi_cdl_check_cmd(struct scsi_device *sdev, u8 opcode, u16 sa,
599 /* Check operation code */
600 ret = scsi_report_opcode(sdev, buf, SCSI_CDL_CHECK_BUF_LEN, opcode, sa);
604 if ((buf[1] & 0x03) != 0x03)
608 * See SPC-6, One_command parameter data format for
609 * REPORT SUPPORTED OPERATION CODES. We have the following cases
610 * depending on rwcdlp (buf[0] & 0x01) value:
611 * - rwcdlp == 0: then cdlp indicates support for the A mode page when
612 * it is equal to 1 and for the B mode page when it is
614 * - rwcdlp == 1: then cdlp indicates support for the T2A mode page
615 * when it is equal to 1 and for the T2B mode page when
617 * Overall, to detect support for command duration limits, we only need
618 * to check that cdlp is 1 or 2.
620 cdlp = (buf[1] & 0x18) >> 3;
622 return cdlp == 0x01 || cdlp == 0x02;
626 * scsi_cdl_check - Check if a SCSI device supports Command Duration Limits
627 * @sdev: The device to check
629 void scsi_cdl_check(struct scsi_device *sdev)
635 * Support for CDL was defined in SPC-5. Ignore devices reporting an
636 * lower SPC version. This also avoids problems with old drives choking
637 * on MAINTENANCE_IN / MI_REPORT_SUPPORTED_OPERATION_CODES with a
638 * service action specified, as done in scsi_cdl_check_cmd().
640 if (sdev->scsi_level < SCSI_SPC_5) {
641 sdev->cdl_supported = 0;
645 buf = kmalloc(SCSI_CDL_CHECK_BUF_LEN, GFP_KERNEL);
647 sdev->cdl_supported = 0;
651 /* Check support for READ_16, WRITE_16, READ_32 and WRITE_32 commands */
653 scsi_cdl_check_cmd(sdev, READ_16, 0, buf) ||
654 scsi_cdl_check_cmd(sdev, WRITE_16, 0, buf) ||
655 scsi_cdl_check_cmd(sdev, VARIABLE_LENGTH_CMD, READ_32, buf) ||
656 scsi_cdl_check_cmd(sdev, VARIABLE_LENGTH_CMD, WRITE_32, buf);
659 * We have CDL support: force the use of READ16/WRITE16.
660 * READ32 and WRITE32 will be used for devices that support
661 * the T10_PI_TYPE2_PROTECTION protection type.
663 sdev->use_16_for_rw = 1;
664 sdev->use_10_for_rw = 0;
666 sdev->cdl_supported = 1;
668 sdev->cdl_supported = 0;
675 * scsi_cdl_enable - Enable or disable a SCSI device supports for Command
677 * @sdev: The target device
678 * @enable: the target state
680 int scsi_cdl_enable(struct scsi_device *sdev, bool enable)
682 struct scsi_mode_data data;
683 struct scsi_sense_hdr sshdr;
684 struct scsi_vpd *vpd;
689 if (!sdev->cdl_supported)
693 vpd = rcu_dereference(sdev->vpd_pg89);
699 * For ATA devices, CDL needs to be enabled with a SET FEATURES command.
705 ret = scsi_mode_sense(sdev, 0x08, 0x0a, 0xf2, buf, sizeof(buf),
706 5 * HZ, 3, &data, NULL);
710 /* Enable CDL using the ATA feature page */
711 len = min_t(size_t, sizeof(buf),
712 data.length - data.header_length -
713 data.block_descriptor_length);
714 buf_data = buf + data.header_length +
715 data.block_descriptor_length;
721 ret = scsi_mode_select(sdev, 1, 0, buf_data, len, 5 * HZ, 3,
724 if (ret > 0 && scsi_sense_valid(&sshdr))
725 scsi_print_sense_hdr(sdev,
726 dev_name(&sdev->sdev_gendev), &sshdr);
731 sdev->cdl_enable = enable;
737 * scsi_device_get - get an additional reference to a scsi_device
738 * @sdev: device to get a reference to
740 * Description: Gets a reference to the scsi_device and increments the use count
741 * of the underlying LLDD module. You must hold host_lock of the
742 * parent Scsi_Host or already have a reference when calling this.
744 * This will fail if a device is deleted or cancelled, or when the LLD module
745 * is in the process of being unloaded.
747 int scsi_device_get(struct scsi_device *sdev)
749 if (sdev->sdev_state == SDEV_DEL || sdev->sdev_state == SDEV_CANCEL)
751 if (!try_module_get(sdev->host->hostt->module))
753 if (!get_device(&sdev->sdev_gendev))
754 goto fail_put_module;
758 module_put(sdev->host->hostt->module);
762 EXPORT_SYMBOL(scsi_device_get);
765 * scsi_device_put - release a reference to a scsi_device
766 * @sdev: device to release a reference on.
768 * Description: Release a reference to the scsi_device and decrements the use
769 * count of the underlying LLDD module. The device is freed once the last
772 void scsi_device_put(struct scsi_device *sdev)
774 struct module *mod = sdev->host->hostt->module;
776 put_device(&sdev->sdev_gendev);
779 EXPORT_SYMBOL(scsi_device_put);
781 /* helper for shost_for_each_device, see that for documentation */
782 struct scsi_device *__scsi_iterate_devices(struct Scsi_Host *shost,
783 struct scsi_device *prev)
785 struct list_head *list = (prev ? &prev->siblings : &shost->__devices);
786 struct scsi_device *next = NULL;
789 spin_lock_irqsave(shost->host_lock, flags);
790 while (list->next != &shost->__devices) {
791 next = list_entry(list->next, struct scsi_device, siblings);
792 /* skip devices that we can't get a reference to */
793 if (!scsi_device_get(next))
798 spin_unlock_irqrestore(shost->host_lock, flags);
801 scsi_device_put(prev);
804 EXPORT_SYMBOL(__scsi_iterate_devices);
807 * starget_for_each_device - helper to walk all devices of a target
808 * @starget: target whose devices we want to iterate over.
809 * @data: Opaque passed to each function call.
810 * @fn: Function to call on each device
812 * This traverses over each device of @starget. The devices have
813 * a reference that must be released by scsi_host_put when breaking
816 void starget_for_each_device(struct scsi_target *starget, void *data,
817 void (*fn)(struct scsi_device *, void *))
819 struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
820 struct scsi_device *sdev;
822 shost_for_each_device(sdev, shost) {
823 if ((sdev->channel == starget->channel) &&
824 (sdev->id == starget->id))
828 EXPORT_SYMBOL(starget_for_each_device);
831 * __starget_for_each_device - helper to walk all devices of a target (UNLOCKED)
832 * @starget: target whose devices we want to iterate over.
833 * @data: parameter for callback @fn()
834 * @fn: callback function that is invoked for each device
836 * This traverses over each device of @starget. It does _not_
837 * take a reference on the scsi_device, so the whole loop must be
838 * protected by shost->host_lock.
840 * Note: The only reason why drivers would want to use this is because
841 * they need to access the device list in irq context. Otherwise you
842 * really want to use starget_for_each_device instead.
844 void __starget_for_each_device(struct scsi_target *starget, void *data,
845 void (*fn)(struct scsi_device *, void *))
847 struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
848 struct scsi_device *sdev;
850 __shost_for_each_device(sdev, shost) {
851 if ((sdev->channel == starget->channel) &&
852 (sdev->id == starget->id))
856 EXPORT_SYMBOL(__starget_for_each_device);
859 * __scsi_device_lookup_by_target - find a device given the target (UNLOCKED)
860 * @starget: SCSI target pointer
861 * @lun: SCSI Logical Unit Number
863 * Description: Looks up the scsi_device with the specified @lun for a given
864 * @starget. The returned scsi_device does not have an additional
865 * reference. You must hold the host's host_lock over this call and
866 * any access to the returned scsi_device. A scsi_device in state
867 * SDEV_DEL is skipped.
869 * Note: The only reason why drivers should use this is because
870 * they need to access the device list in irq context. Otherwise you
871 * really want to use scsi_device_lookup_by_target instead.
873 struct scsi_device *__scsi_device_lookup_by_target(struct scsi_target *starget,
876 struct scsi_device *sdev;
878 list_for_each_entry(sdev, &starget->devices, same_target_siblings) {
879 if (sdev->sdev_state == SDEV_DEL)
887 EXPORT_SYMBOL(__scsi_device_lookup_by_target);
890 * scsi_device_lookup_by_target - find a device given the target
891 * @starget: SCSI target pointer
892 * @lun: SCSI Logical Unit Number
894 * Description: Looks up the scsi_device with the specified @lun for a given
895 * @starget. The returned scsi_device has an additional reference that
896 * needs to be released with scsi_device_put once you're done with it.
898 struct scsi_device *scsi_device_lookup_by_target(struct scsi_target *starget,
901 struct scsi_device *sdev;
902 struct Scsi_Host *shost = dev_to_shost(starget->dev.parent);
905 spin_lock_irqsave(shost->host_lock, flags);
906 sdev = __scsi_device_lookup_by_target(starget, lun);
907 if (sdev && scsi_device_get(sdev))
909 spin_unlock_irqrestore(shost->host_lock, flags);
913 EXPORT_SYMBOL(scsi_device_lookup_by_target);
916 * __scsi_device_lookup - find a device given the host (UNLOCKED)
917 * @shost: SCSI host pointer
918 * @channel: SCSI channel (zero if only one channel)
919 * @id: SCSI target number (physical unit number)
920 * @lun: SCSI Logical Unit Number
922 * Description: Looks up the scsi_device with the specified @channel, @id, @lun
923 * for a given host. The returned scsi_device does not have an additional
924 * reference. You must hold the host's host_lock over this call and any access
925 * to the returned scsi_device.
927 * Note: The only reason why drivers would want to use this is because
928 * they need to access the device list in irq context. Otherwise you
929 * really want to use scsi_device_lookup instead.
931 struct scsi_device *__scsi_device_lookup(struct Scsi_Host *shost,
932 uint channel, uint id, u64 lun)
934 struct scsi_device *sdev;
936 list_for_each_entry(sdev, &shost->__devices, siblings) {
937 if (sdev->sdev_state == SDEV_DEL)
939 if (sdev->channel == channel && sdev->id == id &&
946 EXPORT_SYMBOL(__scsi_device_lookup);
949 * scsi_device_lookup - find a device given the host
950 * @shost: SCSI host pointer
951 * @channel: SCSI channel (zero if only one channel)
952 * @id: SCSI target number (physical unit number)
953 * @lun: SCSI Logical Unit Number
955 * Description: Looks up the scsi_device with the specified @channel, @id, @lun
956 * for a given host. The returned scsi_device has an additional reference that
957 * needs to be released with scsi_device_put once you're done with it.
959 struct scsi_device *scsi_device_lookup(struct Scsi_Host *shost,
960 uint channel, uint id, u64 lun)
962 struct scsi_device *sdev;
965 spin_lock_irqsave(shost->host_lock, flags);
966 sdev = __scsi_device_lookup(shost, channel, id, lun);
967 if (sdev && scsi_device_get(sdev))
969 spin_unlock_irqrestore(shost->host_lock, flags);
973 EXPORT_SYMBOL(scsi_device_lookup);
975 MODULE_DESCRIPTION("SCSI core");
976 MODULE_LICENSE("GPL");
978 module_param(scsi_logging_level, int, S_IRUGO|S_IWUSR);
979 MODULE_PARM_DESC(scsi_logging_level, "a bit mask of logging levels");
981 static int __init init_scsi(void)
985 error = scsi_init_procfs();
988 error = scsi_init_devinfo();
991 error = scsi_init_hosts();
993 goto cleanup_devlist;
994 error = scsi_init_sysctl();
997 error = scsi_sysfs_register();
1001 scsi_netlink_init();
1003 printk(KERN_NOTICE "SCSI subsystem initialized\n");
1011 scsi_exit_devinfo();
1016 printk(KERN_ERR "SCSI subsystem failed to initialize, error = %d\n",
1021 static void __exit exit_scsi(void)
1023 scsi_netlink_exit();
1024 scsi_sysfs_unregister();
1027 scsi_exit_devinfo();
1032 subsys_initcall(init_scsi);
1033 module_exit(exit_scsi);