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1// SPDX-License-Identifier: GPL-2.0-only2/*3 * scsi.c Copyright (C) 1992 Drew Eckhardt4 * Copyright (C) 1993, 1994, 1995, 1999 Eric Youngdale5 * Copyright (C) 2002, 2003 Christoph Hellwig6 *7 * generic mid-level SCSI driver8 * Initial versions: Drew Eckhardt9 * Subsequent revisions: Eric Youngdale10 *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 to19 * add scatter-gather, multiple outstanding request, and other20 * enhancements.21 *22 * Native multichannel, wide scsi, /proc/scsi and hot plugging23 * 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 by32 * Leonard N. Zubkoff <lnz@dandelion.com>33 *34 * Converted cli() code to spinlocks, Ingo Molnar35 *36 * Jiffies wrap fixes (host->resetting), 3 Dec 1998 Andrea Arcangeli37 *38 * out_of_space hacks, D. Gilbert (dpg) 99060839 */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_POINTS73#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#endif87 88#ifdef CONFIG_SCSI_LOGGING89void 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 address99 *100 * 3: same as 2101 *102 * 4: same as 3103 */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 conditionally123 * sense data for failures or non SUCCESS dispositions.124 *125 * 2: same as 1 but for all command completions.126 *127 * 3: same as 2128 *129 * 4: same as 3 plus dump extra junk130 */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#endif149 150/**151 * scsi_finish_command - cleanup and pass command back to upper layer152 * @cmd: the command153 *154 * Description: Pass command off to upper layer for finishing of I/O155 * 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 longer170 * 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 and191 * simply return a residue instead, so subtract off the192 * residue if drv->done() error processing indicates no193 * 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 depth212 * @sdev: SCSI Device in question213 * @depth: number of commands allowed to be queued to the driver214 *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 depth237 * @sdev: SCSI Device in question238 * @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 a242 * specific SCSI device to determine if and when there is a243 * 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_lun247 * as the untagged command depth248 *249 * Lock Status: None held on entry250 *251 * Notes: Low level drivers may call this at any time and we will do252 * "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 same259 * jiffies count, they could all be from260 * 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 page282 * @sdev: The device to ask283 * @buffer: Where to put the result284 * @page: Which Vital Product Data to return285 * @len: The length of the buffer286 *287 * This is an internal helper function. You probably want to use288 * 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, but310 * 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 that319 * 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 page346 * 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 page366 * is. This is done to prevent problems on legacy devices367 * which can not handle allocation lengths as large as368 * 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 device386 * @sdev: The device to ask387 * @page: Which Vital Product Data to return388 * @buf: where to store the VPD389 * @buf_len: number of bytes in the VPD buffer area390 *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 @buf394 * with the data from that page and return 0. If the VPD page is not395 * 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 reported413 * 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 device430 * @sdev: The device to ask431 * @page: Which Vital Product Data to return432 *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 reported447 * 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 structure492 * @sdev: The device to ask493 *494 * Attach the 'Device Identification' VPD page (0x83) and the495 * 'Unit Serial Number' VPD page (0x80) to a SCSI device496 * structure. This information can be used to identify the device497 * 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 supported535 * @sdev: scsi device to query536 * @buffer: scratch buffer (must be at least 20 bytes long)537 * @len: length of buffer538 * @opcode: opcode for the command to look up539 * @sa: service action for the command to look up540 *541 * Uses the REPORT SUPPORTED OPERATION CODES to check support for the542 * command identified with @opcode and @sa. If the command does not543 * 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 to545 * 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 64601 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 for618 * REPORT SUPPORTED OPERATION CODES. We have the following cases619 * depending on rwcdlp (buf[0] & 0x01) value:620 * - rwcdlp == 0: then cdlp indicates support for the A mode page when621 * it is equal to 1 and for the B mode page when it is622 * equal to 2.623 * - rwcdlp == 1: then cdlp indicates support for the T2A mode page624 * when it is equal to 1 and for the T2B mode page when625 * it is equal to 2.626 * Overall, to detect support for command duration limits, we only need627 * 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 Limits636 * @sdev: The device to check637 */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 an645 * lower SPC version. This also avoids problems with old drives choking646 * on MAINTENANCE_IN / MI_REPORT_SUPPORTED_OPERATION_CODES with a647 * 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 support670 * 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 drive679 * feature status is consistent with the user controlled680 * 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 Command692 * Duration Limits693 * @sdev: The target device694 * @enable: the target state695 */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 else735 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_device754 * @sdev: device to get a reference to755 *756 * Description: Gets a reference to the scsi_device and increments the use count757 * of the underlying LLDD module. You must hold host_lock of the758 * 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 module761 * 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_device782 * @sdev: device to release a reference on.783 *784 * Description: Release a reference to the scsi_device and decrements the use785 * count of the underlying LLDD module. The device is freed once the last786 * 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 target824 * @starget: target whose devices we want to iterate over.825 * @data: Opaque passed to each function call.826 * @fn: Function to call on each device827 *828 * This traverses over each device of @starget. The devices have829 * a reference that must be released by scsi_host_put when breaking830 * 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 device851 *852 * This traverses over each device of @starget. It does _not_853 * take a reference on the scsi_device, so the whole loop must be854 * protected by shost->host_lock.855 *856 * Note: The only reason why drivers would want to use this is because857 * they need to access the device list in irq context. Otherwise you858 * 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 pointer877 * @lun: SCSI Logical Unit Number878 *879 * Description: Looks up the scsi_device with the specified @lun for a given880 * @starget. The returned scsi_device does not have an additional881 * reference. You must hold the host's host_lock over this call and882 * any access to the returned scsi_device. A scsi_device in state883 * SDEV_DEL is skipped.884 *885 * Note: The only reason why drivers should use this is because886 * they need to access the device list in irq context. Otherwise you887 * 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 target907 * @starget: SCSI target pointer908 * @lun: SCSI Logical Unit Number909 *910 * Description: Looks up the scsi_device with the specified @lun for a given911 * @starget. The returned scsi_device has an additional reference that912 * 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 pointer934 * @channel: SCSI channel (zero if only one channel)935 * @id: SCSI target number (physical unit number)936 * @lun: SCSI Logical Unit Number937 *938 * Description: Looks up the scsi_device with the specified @channel, @id, @lun939 * for a given host. The returned scsi_device does not have an additional940 * reference. You must hold the host's host_lock over this call and any access941 * to the returned scsi_device.942 *943 * Note: The only reason why drivers would want to use this is because944 * they need to access the device list in irq context. Otherwise you945 * 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 host966 * @shost: SCSI host pointer967 * @channel: SCSI channel (zero if only one channel)968 * @id: SCSI target number (physical unit number)969 * @lun: SCSI Logical Unit Number970 *971 * Description: Looks up the scsi_device with the specified @channel, @id, @lun972 * for a given host. The returned scsi_device has an additional reference that973 * 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);1050