1// SPDX-License-Identifier: GPL-2.0-only 2/* 3 * scsi.c Copyright (C) 1992 Drew Eckhardt 4 * Copyright (C) 1993, 1994, 1995, 1999 Eric Youngdale 5 * Copyright (C) 2002, 2003 Christoph Hellwig 6 * 7 * generic mid-level SCSI driver 8 * Initial versions: Drew Eckhardt 9 * Subsequent revisions: Eric Youngdale 10 * 11 * <drew@colorado.edu> 12 * 13 * Bug correction thanks go to : 14 * Rik Faith <faith@cs.unc.edu> 15 * Tommy Thorn <tthorn> 16 * Thomas Wuensche <tw@fgb1.fgb.mw.tu-muenchen.de> 17 * 18 * Modified by Eric Youngdale eric@andante.org or ericy@gnu.ai.mit.edu to 19 * add scatter-gather, multiple outstanding request, and other 20 * enhancements. 21 * 22 * Native multichannel, wide scsi, /proc/scsi and hot plugging 23 * support added by Michael Neuffer <mike@i-connect.net> 24 * 25 * Added request_module("scsi_hostadapter") for kerneld: 26 * (Put an "alias scsi_hostadapter your_hostadapter" in /etc/modprobe.conf) 27 * Bjorn Ekwall <bj0rn@blox.se> 28 * (changed to kmod) 29 * 30 * Major improvements to the timeout, abort, and reset processing, 31 * as well as performance modifications for large queue depths by 32 * Leonard N. Zubkoff <lnz@dandelion.com> 33 * 34 * Converted cli() code to spinlocks, Ingo Molnar 35 * 36 * Jiffies wrap fixes (host->resetting), 3 Dec 1998 Andrea Arcangeli 37 * 38 * out_of_space hacks, D. Gilbert (dpg) 990608 39 */ 40 41#include <linux/module.h> 42#include <linux/moduleparam.h> 43#include <linux/kernel.h> 44#include <linux/timer.h> 45#include <linux/string.h> 46#include <linux/slab.h> 47#include <linux/blkdev.h> 48#include <linux/delay.h> 49#include <linux/init.h> 50#include <linux/completion.h> 51#include <linux/unistd.h> 52#include <linux/spinlock.h> 53#include <linux/kmod.h> 54#include <linux/interrupt.h> 55#include <linux/notifier.h> 56#include <linux/cpu.h> 57#include <linux/mutex.h> 58#include <asm/unaligned.h> 59 60#include <scsi/scsi.h> 61#include <scsi/scsi_cmnd.h> 62#include <scsi/scsi_dbg.h> 63#include <scsi/scsi_device.h> 64#include <scsi/scsi_driver.h> 65#include <scsi/scsi_eh.h> 66#include <scsi/scsi_host.h> 67#include <scsi/scsi_tcq.h> 68 69#include "scsi_priv.h" 70#include "scsi_logging.h" 71 72#define CREATE_TRACE_POINTS 73#include <trace/events/scsi.h> 74 75/* 76 * Definitions and constants. 77 */ 78 79/* 80 * Note - the initial logging level can be set here to log events at boot time. 81 * After the system is up, you may enable logging via the /proc interface. 82 */ 83unsigned int scsi_logging_level; 84#if defined(CONFIG_SCSI_LOGGING) 85EXPORT_SYMBOL(scsi_logging_level); 86#endif 87 88#ifdef CONFIG_SCSI_LOGGING 89void scsi_log_send(struct scsi_cmnd *cmd) 90{ 91 unsigned int level; 92 93 /* 94 * If ML QUEUE log level is greater than or equal to: 95 * 96 * 1: nothing (match completion) 97 * 98 * 2: log opcode + command of all commands + cmd address 99 * 100 * 3: same as 2 101 * 102 * 4: same as 3 103 */ 104 if (unlikely(scsi_logging_level)) { 105 level = SCSI_LOG_LEVEL(SCSI_LOG_MLQUEUE_SHIFT, 106 SCSI_LOG_MLQUEUE_BITS); 107 if (level > 1) { 108 scmd_printk(KERN_INFO, cmd, 109 "Send: scmd 0x%p\n", cmd); 110 scsi_print_command(cmd); 111 } 112 } 113} 114 115void scsi_log_completion(struct scsi_cmnd *cmd, int disposition) 116{ 117 unsigned int level; 118 119 /* 120 * If ML COMPLETE log level is greater than or equal to: 121 * 122 * 1: log disposition, result, opcode + command, and conditionally 123 * sense data for failures or non SUCCESS dispositions. 124 * 125 * 2: same as 1 but for all command completions. 126 * 127 * 3: same as 2 128 * 129 * 4: same as 3 plus dump extra junk 130 */ 131 if (unlikely(scsi_logging_level)) { 132 level = SCSI_LOG_LEVEL(SCSI_LOG_MLCOMPLETE_SHIFT, 133 SCSI_LOG_MLCOMPLETE_BITS); 134 if (((level > 0) && (cmd->result || disposition != SUCCESS)) || 135 (level > 1)) { 136 scsi_print_result(cmd, "Done", disposition); 137 scsi_print_command(cmd); 138 if (scsi_status_is_check_condition(cmd->result)) 139 scsi_print_sense(cmd); 140 if (level > 3) 141 scmd_printk(KERN_INFO, cmd, 142 "scsi host busy %d failed %d\n", 143 scsi_host_busy(cmd->device->host), 144 cmd->device->host->host_failed); 145 } 146 } 147} 148#endif 149 150/** 151 * scsi_finish_command - cleanup and pass command back to upper layer 152 * @cmd: the command 153 * 154 * Description: Pass command off to upper layer for finishing of I/O 155 * request, waking processes that are waiting on results, 156 * etc. 157 */ 158void scsi_finish_command(struct scsi_cmnd *cmd) 159{ 160 struct scsi_device *sdev = cmd->device; 161 struct scsi_target *starget = scsi_target(sdev); 162 struct Scsi_Host *shost = sdev->host; 163 struct scsi_driver *drv; 164 unsigned int good_bytes; 165 166 scsi_device_unbusy(sdev, cmd); 167 168 /* 169 * Clear the flags that say that the device/target/host is no longer 170 * capable of accepting new commands. 171 */ 172 if (atomic_read(&shost->host_blocked)) 173 atomic_set(&shost->host_blocked, 0); 174 if (atomic_read(&starget->target_blocked)) 175 atomic_set(&starget->target_blocked, 0); 176 if (atomic_read(&sdev->device_blocked)) 177 atomic_set(&sdev->device_blocked, 0); 178 179 SCSI_LOG_MLCOMPLETE(4, sdev_printk(KERN_INFO, sdev, 180 "Notifying upper driver of completion " 181 "(result %x)\n", cmd->result)); 182 183 good_bytes = scsi_bufflen(cmd); 184 if (!blk_rq_is_passthrough(scsi_cmd_to_rq(cmd))) { 185 int old_good_bytes = good_bytes; 186 drv = scsi_cmd_to_driver(cmd); 187 if (drv->done) 188 good_bytes = drv->done(cmd); 189 /* 190 * USB may not give sense identifying bad sector and 191 * simply return a residue instead, so subtract off the 192 * residue if drv->done() error processing indicates no 193 * change to the completion length. 194 */ 195 if (good_bytes == old_good_bytes) 196 good_bytes -= scsi_get_resid(cmd); 197 } 198 scsi_io_completion(cmd, good_bytes); 199} 200 201 202/* 203 * 4096 is big enough for saturating fast SCSI LUNs. 204 */ 205int scsi_device_max_queue_depth(struct scsi_device *sdev) 206{ 207 return min_t(int, sdev->host->can_queue, 4096); 208} 209 210/** 211 * scsi_change_queue_depth - change a device's queue depth 212 * @sdev: SCSI Device in question 213 * @depth: number of commands allowed to be queued to the driver 214 * 215 * Sets the device queue depth and returns the new value. 216 */ 217int scsi_change_queue_depth(struct scsi_device *sdev, int depth) 218{ 219 depth = min_t(int, depth, scsi_device_max_queue_depth(sdev)); 220 221 if (depth > 0) { 222 sdev->queue_depth = depth; 223 wmb(); 224 } 225 226 if (sdev->request_queue) 227 blk_set_queue_depth(sdev->request_queue, depth); 228 229 sbitmap_resize(&sdev->budget_map, sdev->queue_depth); 230 231 return sdev->queue_depth; 232} 233EXPORT_SYMBOL(scsi_change_queue_depth); 234 235/** 236 * scsi_track_queue_full - track QUEUE_FULL events to adjust queue depth 237 * @sdev: SCSI Device in question 238 * @depth: Current number of outstanding SCSI commands on this device, 239 * not counting the one returned as QUEUE_FULL. 240 * 241 * Description: This function will track successive QUEUE_FULL events on a 242 * specific SCSI device to determine if and when there is a 243 * need to adjust the queue depth on the device. 244 * 245 * Returns: 0 - No change needed, >0 - Adjust queue depth to this new depth, 246 * -1 - Drop back to untagged operation using host->cmd_per_lun 247 * as the untagged command depth 248 * 249 * Lock Status: None held on entry 250 * 251 * Notes: Low level drivers may call this at any time and we will do 252 * "The Right Thing." We are interrupt context safe. 253 */ 254int scsi_track_queue_full(struct scsi_device *sdev, int depth) 255{ 256 257 /* 258 * Don't let QUEUE_FULLs on the same 259 * jiffies count, they could all be from 260 * same event. 261 */ 262 if ((jiffies >> 4) == (sdev->last_queue_full_time >> 4)) 263 return 0; 264 265 sdev->last_queue_full_time = jiffies; 266 if (sdev->last_queue_full_depth != depth) { 267 sdev->last_queue_full_count = 1; 268 sdev->last_queue_full_depth = depth; 269 } else { 270 sdev->last_queue_full_count++; 271 } 272 273 if (sdev->last_queue_full_count <= 10) 274 return 0; 275 276 return scsi_change_queue_depth(sdev, depth); 277} 278EXPORT_SYMBOL(scsi_track_queue_full); 279 280/** 281 * scsi_vpd_inquiry - Request a device provide us with a VPD page 282 * @sdev: The device to ask 283 * @buffer: Where to put the result 284 * @page: Which Vital Product Data to return 285 * @len: The length of the buffer 286 * 287 * This is an internal helper function. You probably want to use 288 * scsi_get_vpd_page instead. 289 * 290 * Returns size of the vpd page on success or a negative error number. 291 */ 292static int scsi_vpd_inquiry(struct scsi_device *sdev, unsigned char *buffer, 293 u8 page, unsigned len) 294{ 295 int result; 296 unsigned char cmd[16]; 297 298 if (len < 4) 299 return -EINVAL; 300 301 cmd[0] = INQUIRY; 302 cmd[1] = 1; /* EVPD */ 303 cmd[2] = page; 304 cmd[3] = len >> 8; 305 cmd[4] = len & 0xff; 306 cmd[5] = 0; /* Control byte */ 307 308 /* 309 * I'm not convinced we need to try quite this hard to get VPD, but 310 * all the existing users tried this hard. 311 */ 312 result = scsi_execute_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 result -= SCSI_VPD_HEADER_SIZE; 354 if (!memchr(&vpd[SCSI_VPD_HEADER_SIZE], page, result)) 355 return 0; 356 } 357 /* 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. 362 */ 363 result = scsi_vpd_inquiry(sdev, vpd, page, SCSI_VPD_HEADER_SIZE); 364 if (result < 0) 365 return 0; 366 367 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); 371 return 0; 372 } 373 374 return result; 375} 376 377/** 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 383 * 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. 389 */ 390int scsi_get_vpd_page(struct scsi_device *sdev, u8 page, unsigned char *buf, 391 int buf_len) 392{ 393 int result, vpd_len; 394 395 if (!scsi_device_supports_vpd(sdev)) 396 return -EINVAL; 397 398 vpd_len = scsi_get_vpd_size(sdev, page); 399 if (vpd_len <= 0) 400 return -EINVAL; 401 402 vpd_len = min(vpd_len, buf_len); 403 404 /* 405 * Fetch the actual page. Since the appropriate size was reported 406 * by the device it is now safe to ask for something bigger. 407 */ 408 memset(buf, 0, buf_len); 409 result = scsi_vpd_inquiry(sdev, buf, page, vpd_len); 410 if (result < 0) 411 return -EINVAL; 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); 416 417 return 0; 418} 419EXPORT_SYMBOL_GPL(scsi_get_vpd_page); 420 421/** 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 425 * 426 * Returns %NULL upon failure. 427 */ 428static struct scsi_vpd *scsi_get_vpd_buf(struct scsi_device *sdev, u8 page) 429{ 430 struct scsi_vpd *vpd_buf; 431 int vpd_len, result; 432 433 vpd_len = scsi_get_vpd_size(sdev, page); 434 if (vpd_len <= 0) 435 return NULL; 436 437retry_pg: 438 /* 439 * Fetch the actual page. Since the appropriate size was reported 440 * by the device it is now safe to ask for something bigger. 441 */ 442 vpd_buf = kmalloc(sizeof(*vpd_buf) + vpd_len, GFP_KERNEL); 443 if (!vpd_buf) 444 return NULL; 445 446 result = scsi_vpd_inquiry(sdev, vpd_buf->data, page, vpd_len); 447 if (result < 0) { 448 kfree(vpd_buf); 449 return NULL; 450 } 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); 455 vpd_len = result; 456 kfree(vpd_buf); 457 goto retry_pg; 458 } 459 460 vpd_buf->len = result; 461 462 return vpd_buf; 463} 464 465static void scsi_update_vpd_page(struct scsi_device *sdev, u8 page, 466 struct scsi_vpd __rcu **sdev_vpd_buf) 467{ 468 struct scsi_vpd *vpd_buf; 469 470 vpd_buf = scsi_get_vpd_buf(sdev, page); 471 if (!vpd_buf) 472 return; 473 474 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); 478 479 if (vpd_buf) 480 kfree_rcu(vpd_buf, rcu); 481} 482 483/** 484 * scsi_attach_vpd - Attach Vital Product Data to a SCSI device structure 485 * @sdev: The device to ask 486 * 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 490 * uniquely. 491 */ 492void scsi_attach_vpd(struct scsi_device *sdev) 493{ 494 int i; 495 struct scsi_vpd *vpd_buf; 496 497 if (!scsi_device_supports_vpd(sdev)) 498 return; 499 500 /* Ask for all the pages supported by this device */ 501 vpd_buf = scsi_get_vpd_buf(sdev, 0); 502 if (!vpd_buf) 503 return; 504 505 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); 520 if (vpd_buf->data[i] == 0xb7) 521 scsi_update_vpd_page(sdev, 0xb7, &sdev->vpd_pgb7); 522 } 523 kfree(vpd_buf); 524} 525 526/** 527 * scsi_report_opcode - Find out if a given command is supported 528 * @sdev: scsi device to query 529 * @buffer: scratch buffer (must be at least 20 bytes long) 530 * @len: length of buffer 531 * @opcode: opcode for the command to look up 532 * @sa: service action for the command to look up 533 * 534 * Uses the REPORT SUPPORTED OPERATION CODES to check support for the 535 * command identified with @opcode and @sa. If the command does not 536 * have a service action, @sa must be 0. Returns -EINVAL if RSOC fails, 537 * 0 if the command is not supported and 1 if the device claims to 538 * support the command. 539 */ 540int scsi_report_opcode(struct scsi_device *sdev, unsigned char *buffer, 541 unsigned int len, unsigned char opcode, 542 unsigned short sa) 543{ 544 unsigned char cmd[16]; 545 struct scsi_sense_hdr sshdr; 546 int result, request_len; 547 const struct scsi_exec_args exec_args = { 548 .sshdr = &sshdr, 549 }; 550 551 if (sdev->no_report_opcodes || sdev->scsi_level < SCSI_SPC_3) 552 return -EINVAL; 553 554 /* RSOC header + size of command we are asking about */ 555 request_len = 4 + COMMAND_SIZE(opcode); 556 if (request_len > len) { 557 dev_warn_once(&sdev->sdev_gendev, 558 "%s: len %u bytes, opcode 0x%02x needs %u\n", 559 __func__, len, opcode, request_len); 560 return -EINVAL; 561 } 562 563 memset(cmd, 0, 16); 564 cmd[0] = MAINTENANCE_IN; 565 cmd[1] = MI_REPORT_SUPPORTED_OPERATION_CODES; 566 if (!sa) { 567 cmd[2] = 1; /* One command format */ 568 cmd[3] = opcode; 569 } else { 570 cmd[2] = 3; /* One command format with service action */ 571 cmd[3] = opcode; 572 put_unaligned_be16(sa, &cmd[4]); 573 } 574 put_unaligned_be32(request_len, &cmd[6]); 575 memset(buffer, 0, len); 576 577 result = scsi_execute_cmd(sdev, cmd, REQ_OP_DRV_IN, buffer, 578 request_len, 30 * HZ, 3, &exec_args); 579 if (result < 0) 580 return result; 581 if (result && scsi_sense_valid(&sshdr) && 582 sshdr.sense_key == ILLEGAL_REQUEST && 583 (sshdr.asc == 0x20 || sshdr.asc == 0x24) && sshdr.ascq == 0x00) 584 return -EINVAL; 585 586 if ((buffer[1] & 3) == 3) /* Command supported */ 587 return 1; 588 589 return 0; 590} 591EXPORT_SYMBOL(scsi_report_opcode); 592 593#define SCSI_CDL_CHECK_BUF_LEN 64 594 595static bool scsi_cdl_check_cmd(struct scsi_device *sdev, u8 opcode, u16 sa, 596 unsigned char *buf) 597{ 598 int ret; 599 u8 cdlp; 600 601 /* Check operation code */ 602 ret = scsi_report_opcode(sdev, buf, SCSI_CDL_CHECK_BUF_LEN, opcode, sa); 603 if (ret <= 0) 604 return false; 605 606 if ((buf[1] & 0x03) != 0x03) 607 return false; 608 609 /* 610 * See SPC-6, One_command parameter data format for 611 * REPORT SUPPORTED OPERATION CODES. We have the following cases 612 * depending on rwcdlp (buf[0] & 0x01) value: 613 * - rwcdlp == 0: then cdlp indicates support for the A mode page when 614 * it is equal to 1 and for the B mode page when it is 615 * equal to 2. 616 * - rwcdlp == 1: then cdlp indicates support for the T2A mode page 617 * when it is equal to 1 and for the T2B mode page when 618 * it is equal to 2. 619 * Overall, to detect support for command duration limits, we only need 620 * to check that cdlp is 1 or 2. 621 */ 622 cdlp = (buf[1] & 0x18) >> 3; 623 624 return cdlp == 0x01 || cdlp == 0x02; 625} 626 627/** 628 * scsi_cdl_check - Check if a SCSI device supports Command Duration Limits 629 * @sdev: The device to check 630 */ 631void scsi_cdl_check(struct scsi_device *sdev) 632{ 633 bool cdl_supported; 634 unsigned char *buf; 635 636 /* 637 * Support for CDL was defined in SPC-5. Ignore devices reporting an 638 * lower SPC version. This also avoids problems with old drives choking 639 * on MAINTENANCE_IN / MI_REPORT_SUPPORTED_OPERATION_CODES with a 640 * service action specified, as done in scsi_cdl_check_cmd(). 641 */ 642 if (sdev->scsi_level < SCSI_SPC_5) { 643 sdev->cdl_supported = 0; 644 return; 645 } 646 647 buf = kmalloc(SCSI_CDL_CHECK_BUF_LEN, GFP_KERNEL); 648 if (!buf) { 649 sdev->cdl_supported = 0; 650 return; 651 } 652 653 /* Check support for READ_16, WRITE_16, READ_32 and WRITE_32 commands */ 654 cdl_supported = 655 scsi_cdl_check_cmd(sdev, READ_16, 0, buf) || 656 scsi_cdl_check_cmd(sdev, WRITE_16, 0, buf) || 657 scsi_cdl_check_cmd(sdev, VARIABLE_LENGTH_CMD, READ_32, buf) || 658 scsi_cdl_check_cmd(sdev, VARIABLE_LENGTH_CMD, WRITE_32, buf); 659 if (cdl_supported) { 660 /* 661 * We have CDL support: force the use of READ16/WRITE16. 662 * READ32 and WRITE32 will be used for devices that support 663 * the T10_PI_TYPE2_PROTECTION protection type. 664 */ 665 sdev->use_16_for_rw = 1; 666 sdev->use_10_for_rw = 0; 667 668 sdev->cdl_supported = 1; 669 } else { 670 sdev->cdl_supported = 0; 671 } 672 673 kfree(buf); 674} 675 676/** 677 * scsi_cdl_enable - Enable or disable a SCSI device supports for Command 678 * Duration Limits 679 * @sdev: The target device 680 * @enable: the target state 681 */ 682int scsi_cdl_enable(struct scsi_device *sdev, bool enable) 683{ 684 struct scsi_mode_data data; 685 struct scsi_sense_hdr sshdr; 686 struct scsi_vpd *vpd; 687 bool is_ata = false; 688 char buf[64]; 689 int ret; 690 691 if (!sdev->cdl_supported) 692 return -EOPNOTSUPP; 693 694 rcu_read_lock(); 695 vpd = rcu_dereference(sdev->vpd_pg89); 696 if (vpd) 697 is_ata = true; 698 rcu_read_unlock(); 699 700 /* 701 * For ATA devices, CDL needs to be enabled with a SET FEATURES command. 702 */ 703 if (is_ata) { 704 char *buf_data; 705 int len; 706 707 ret = scsi_mode_sense(sdev, 0x08, 0x0a, 0xf2, buf, sizeof(buf), 708 5 * HZ, 3, &data, NULL); 709 if (ret) 710 return -EINVAL; 711 712 /* Enable CDL using the ATA feature page */ 713 len = min_t(size_t, sizeof(buf), 714 data.length - data.header_length - 715 data.block_descriptor_length); 716 buf_data = buf + data.header_length + 717 data.block_descriptor_length; 718 if (enable) 719 buf_data[4] = 0x02; 720 else 721 buf_data[4] = 0; 722 723 ret = scsi_mode_select(sdev, 1, 0, buf_data, len, 5 * HZ, 3, 724 &data, &sshdr); 725 if (ret) { 726 if (ret > 0 && scsi_sense_valid(&sshdr)) 727 scsi_print_sense_hdr(sdev, 728 dev_name(&sdev->sdev_gendev), &sshdr); 729 return ret; 730 } 731 } 732 733 sdev->cdl_enable = enable; 734 735 return 0; 736} 737 738/** 739 * scsi_device_get - get an additional reference to a scsi_device 740 * @sdev: device to get a reference to 741 * 742 * Description: Gets a reference to the scsi_device and increments the use count 743 * of the underlying LLDD module. You must hold host_lock of the 744 * parent Scsi_Host or already have a reference when calling this. 745 * 746 * This will fail if a device is deleted or cancelled, or when the LLD module 747 * is in the process of being unloaded. 748 */ 749int scsi_device_get(struct scsi_device *sdev) 750{ 751 if (sdev->sdev_state == SDEV_DEL || sdev->sdev_state == SDEV_CANCEL) 752 goto fail; 753 if (!try_module_get(sdev->host->hostt->module)) 754 goto fail; 755 if (!get_device(&sdev->sdev_gendev)) 756 goto fail_put_module; 757 return 0; 758 759fail_put_module: 760 module_put(sdev->host->hostt->module); 761fail: 762 return -ENXIO; 763} 764EXPORT_SYMBOL(scsi_device_get); 765 766/** 767 * scsi_device_put - release a reference to a scsi_device 768 * @sdev: device to release a reference on. 769 * 770 * Description: Release a reference to the scsi_device and decrements the use 771 * count of the underlying LLDD module. The device is freed once the last 772 * user vanishes. 773 */ 774void scsi_device_put(struct scsi_device *sdev) 775{ 776 struct module *mod = sdev->host->hostt->module; 777 778 put_device(&sdev->sdev_gendev); 779 module_put(mod); 780} 781EXPORT_SYMBOL(scsi_device_put); 782 783/* helper for shost_for_each_device, see that for documentation */ 784struct scsi_device *__scsi_iterate_devices(struct Scsi_Host *shost, 785 struct scsi_device *prev) 786{ 787 struct list_head *list = (prev ? &prev->siblings : &shost->__devices); 788 struct scsi_device *next = NULL; 789 unsigned long flags; 790 791 spin_lock_irqsave(shost->host_lock, flags); 792 while (list->next != &shost->__devices) { 793 next = list_entry(list->next, struct scsi_device, siblings); 794 /* skip devices that we can't get a reference to */ 795 if (!scsi_device_get(next)) 796 break; 797 next = NULL; 798 list = list->next; 799 } 800 spin_unlock_irqrestore(shost->host_lock, flags); 801 802 if (prev) 803 scsi_device_put(prev); 804 return next; 805} 806EXPORT_SYMBOL(__scsi_iterate_devices); 807 808/** 809 * starget_for_each_device - helper to walk all devices of a target 810 * @starget: target whose devices we want to iterate over. 811 * @data: Opaque passed to each function call. 812 * @fn: Function to call on each device 813 * 814 * This traverses over each device of @starget. The devices have 815 * a reference that must be released by scsi_host_put when breaking 816 * out of the loop. 817 */ 818void starget_for_each_device(struct scsi_target *starget, void *data, 819 void (*fn)(struct scsi_device *, void *)) 820{ 821 struct Scsi_Host *shost = dev_to_shost(starget->dev.parent); 822 struct scsi_device *sdev; 823 824 shost_for_each_device(sdev, shost) { 825 if ((sdev->channel == starget->channel) && 826 (sdev->id == starget->id)) 827 fn(sdev, data); 828 } 829} 830EXPORT_SYMBOL(starget_for_each_device); 831 832/** 833 * __starget_for_each_device - helper to walk all devices of a target (UNLOCKED) 834 * @starget: target whose devices we want to iterate over. 835 * @data: parameter for callback @fn() 836 * @fn: callback function that is invoked for each device 837 * 838 * This traverses over each device of @starget. It does _not_ 839 * take a reference on the scsi_device, so the whole loop must be 840 * protected by shost->host_lock. 841 * 842 * Note: The only reason why drivers would want to use this is because 843 * they need to access the device list in irq context. Otherwise you 844 * really want to use starget_for_each_device instead. 845 **/ 846void __starget_for_each_device(struct scsi_target *starget, void *data, 847 void (*fn)(struct scsi_device *, void *)) 848{ 849 struct Scsi_Host *shost = dev_to_shost(starget->dev.parent); 850 struct scsi_device *sdev; 851 852 __shost_for_each_device(sdev, shost) { 853 if ((sdev->channel == starget->channel) && 854 (sdev->id == starget->id)) 855 fn(sdev, data); 856 } 857} 858EXPORT_SYMBOL(__starget_for_each_device); 859 860/** 861 * __scsi_device_lookup_by_target - find a device given the target (UNLOCKED) 862 * @starget: SCSI target pointer 863 * @lun: SCSI Logical Unit Number 864 * 865 * Description: Looks up the scsi_device with the specified @lun for a given 866 * @starget. The returned scsi_device does not have an additional 867 * reference. You must hold the host's host_lock over this call and 868 * any access to the returned scsi_device. A scsi_device in state 869 * SDEV_DEL is skipped. 870 * 871 * Note: The only reason why drivers should use this is because 872 * they need to access the device list in irq context. Otherwise you 873 * really want to use scsi_device_lookup_by_target instead. 874 **/ 875struct scsi_device *__scsi_device_lookup_by_target(struct scsi_target *starget, 876 u64 lun) 877{ 878 struct scsi_device *sdev; 879 880 list_for_each_entry(sdev, &starget->devices, same_target_siblings) { 881 if (sdev->sdev_state == SDEV_DEL) 882 continue; 883 if (sdev->lun ==lun) 884 return sdev; 885 } 886 887 return NULL; 888} 889EXPORT_SYMBOL(__scsi_device_lookup_by_target); 890 891/** 892 * scsi_device_lookup_by_target - find a device given the target 893 * @starget: SCSI target pointer 894 * @lun: SCSI Logical Unit Number 895 * 896 * Description: Looks up the scsi_device with the specified @lun for a given 897 * @starget. The returned scsi_device has an additional reference that 898 * needs to be released with scsi_device_put once you're done with it. 899 **/ 900struct scsi_device *scsi_device_lookup_by_target(struct scsi_target *starget, 901 u64 lun) 902{ 903 struct scsi_device *sdev; 904 struct Scsi_Host *shost = dev_to_shost(starget->dev.parent); 905 unsigned long flags; 906 907 spin_lock_irqsave(shost->host_lock, flags); 908 sdev = __scsi_device_lookup_by_target(starget, lun); 909 if (sdev && scsi_device_get(sdev)) 910 sdev = NULL; 911 spin_unlock_irqrestore(shost->host_lock, flags); 912 913 return sdev; 914} 915EXPORT_SYMBOL(scsi_device_lookup_by_target); 916 917/** 918 * __scsi_device_lookup - find a device given the host (UNLOCKED) 919 * @shost: SCSI host pointer 920 * @channel: SCSI channel (zero if only one channel) 921 * @id: SCSI target number (physical unit number) 922 * @lun: SCSI Logical Unit Number 923 * 924 * Description: Looks up the scsi_device with the specified @channel, @id, @lun 925 * for a given host. The returned scsi_device does not have an additional 926 * reference. You must hold the host's host_lock over this call and any access 927 * to the returned scsi_device. 928 * 929 * Note: The only reason why drivers would want to use this is because 930 * they need to access the device list in irq context. Otherwise you 931 * really want to use scsi_device_lookup instead. 932 **/ 933struct scsi_device *__scsi_device_lookup(struct Scsi_Host *shost, 934 uint channel, uint id, u64 lun) 935{ 936 struct scsi_device *sdev; 937 938 list_for_each_entry(sdev, &shost->__devices, siblings) { 939 if (sdev->sdev_state == SDEV_DEL) 940 continue; 941 if (sdev->channel == channel && sdev->id == id && 942 sdev->lun ==lun) 943 return sdev; 944 } 945 946 return NULL; 947} 948EXPORT_SYMBOL(__scsi_device_lookup); 949 950/** 951 * scsi_device_lookup - find a device given the host 952 * @shost: SCSI host pointer 953 * @channel: SCSI channel (zero if only one channel) 954 * @id: SCSI target number (physical unit number) 955 * @lun: SCSI Logical Unit Number 956 * 957 * Description: Looks up the scsi_device with the specified @channel, @id, @lun 958 * for a given host. The returned scsi_device has an additional reference that 959 * needs to be released with scsi_device_put once you're done with it. 960 **/ 961struct scsi_device *scsi_device_lookup(struct Scsi_Host *shost, 962 uint channel, uint id, u64 lun) 963{ 964 struct scsi_device *sdev; 965 unsigned long flags; 966 967 spin_lock_irqsave(shost->host_lock, flags); 968 sdev = __scsi_device_lookup(shost, channel, id, lun); 969 if (sdev && scsi_device_get(sdev)) 970 sdev = NULL; 971 spin_unlock_irqrestore(shost->host_lock, flags); 972 973 return sdev; 974} 975EXPORT_SYMBOL(scsi_device_lookup); 976 977MODULE_DESCRIPTION("SCSI core"); 978MODULE_LICENSE("GPL"); 979 980module_param(scsi_logging_level, int, S_IRUGO|S_IWUSR); 981MODULE_PARM_DESC(scsi_logging_level, "a bit mask of logging levels"); 982 983static int __init init_scsi(void) 984{ 985 int error; 986 987 error = scsi_init_procfs(); 988 if (error) 989 goto cleanup_queue; 990 error = scsi_init_devinfo(); 991 if (error) 992 goto cleanup_procfs; 993 error = scsi_init_hosts(); 994 if (error) 995 goto cleanup_devlist; 996 error = scsi_init_sysctl(); 997 if (error) 998 goto cleanup_hosts; 999 error = scsi_sysfs_register(); 1000 if (error) 1001 goto cleanup_sysctl; 1002 1003 scsi_netlink_init(); 1004 1005 printk(KERN_NOTICE "SCSI subsystem initialized\n"); 1006 return 0; 1007 1008cleanup_sysctl: 1009 scsi_exit_sysctl(); 1010cleanup_hosts: 1011 scsi_exit_hosts(); 1012cleanup_devlist: 1013 scsi_exit_devinfo(); 1014cleanup_procfs: 1015 scsi_exit_procfs(); 1016cleanup_queue: 1017 scsi_exit_queue(); 1018 printk(KERN_ERR "SCSI subsystem failed to initialize, error = %d\n", 1019 -error); 1020 return error; 1021} 1022 1023static void __exit exit_scsi(void) 1024{ 1025 scsi_netlink_exit(); 1026 scsi_sysfs_unregister(); 1027 scsi_exit_sysctl(); 1028 scsi_exit_hosts(); 1029 scsi_exit_devinfo(); 1030 scsi_exit_procfs(); 1031 scsi_exit_queue(); 1032} 1033 1034subsys_initcall(init_scsi); 1035module_exit(exit_scsi); 1036