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 */ 83 unsigned int scsi_logging_level; 84 #if defined(CONFIG_SCSI_LOGGING) 85 EXPORT_SYMBOL(scsi_logging_level); 86 #endif 87 88 #ifdef CONFIG_SCSI_LOGGING 89 void 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 } 114 115 void 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 */ 158 void 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 */ 205 int 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 */ 217 int 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 } 233 EXPORT_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 */ 254 int 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 } 278 EXPORT_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 */ 292 static 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 } 330 331 enum scsi_vpd_parameters { 332 SCSI_VPD_HEADER_SIZE = 4, 333 SCSI_VPD_LIST_SIZE = 36, 334 }; 335 336 static 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 */ 390 int 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 } 419 EXPORT_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 */ 428 static 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; 436 437 retry_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 } 464 465 static 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 */ 492 void 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 } 521 kfree(vpd_buf); 522 } 523 524 /** 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 531 * 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. 537 */ 538 int scsi_report_opcode(struct scsi_device *sdev, unsigned char *buffer, 539 unsigned int len, unsigned char opcode, 540 unsigned short sa) 541 { 542 unsigned char cmd[16]; 543 struct scsi_sense_hdr sshdr; 544 int result, request_len; 545 const struct scsi_exec_args exec_args = { 546 .sshdr = &sshdr, 547 }; 548 549 if (sdev->no_report_opcodes || sdev->scsi_level < SCSI_SPC_3) 550 return -EINVAL; 551 552 /* 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); 558 return -EINVAL; 559 } 560 561 memset(cmd, 0, 16); 562 cmd[0] = MAINTENANCE_IN; 563 cmd[1] = MI_REPORT_SUPPORTED_OPERATION_CODES; 564 if (!sa) { 565 cmd[2] = 1; /* One command format */ 566 cmd[3] = opcode; 567 } else { 568 cmd[2] = 3; /* One command format with service action */ 569 cmd[3] = opcode; 570 put_unaligned_be16(sa, &cmd[4]); 571 } 572 put_unaligned_be32(request_len, &cmd[6]); 573 memset(buffer, 0, len); 574 575 result = scsi_execute_cmd(sdev, cmd, REQ_OP_DRV_IN, buffer, 576 request_len, 30 * HZ, 3, &exec_args); 577 if (result < 0) 578 return result; 579 if (result && scsi_sense_valid(&sshdr) && 580 sshdr.sense_key == ILLEGAL_REQUEST && 581 (sshdr.asc == 0x20 || sshdr.asc == 0x24) && sshdr.ascq == 0x00) 582 return -EINVAL; 583 584 if ((buffer[1] & 3) == 3) /* Command supported */ 585 return 1; 586 587 return 0; 588 } 589 EXPORT_SYMBOL(scsi_report_opcode); 590 591 #define SCSI_CDL_CHECK_BUF_LEN 64 592 593 static bool scsi_cdl_check_cmd(struct scsi_device *sdev, u8 opcode, u16 sa, 594 unsigned char *buf) 595 { 596 int ret; 597 u8 cdlp; 598 599 /* Check operation code */ 600 ret = scsi_report_opcode(sdev, buf, SCSI_CDL_CHECK_BUF_LEN, opcode, sa); 601 if (ret <= 0) 602 return false; 603 604 if ((buf[1] & 0x03) != 0x03) 605 return false; 606 607 /* 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 613 * equal to 2. 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 616 * it is equal to 2. 617 * Overall, to detect support for command duration limits, we only need 618 * to check that cdlp is 1 or 2. 619 */ 620 cdlp = (buf[1] & 0x18) >> 3; 621 622 return cdlp == 0x01 || cdlp == 0x02; 623 } 624 625 /** 626 * scsi_cdl_check - Check if a SCSI device supports Command Duration Limits 627 * @sdev: The device to check 628 */ 629 void scsi_cdl_check(struct scsi_device *sdev) 630 { 631 bool cdl_supported; 632 unsigned char *buf; 633 634 /* 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(). 639 */ 640 if (sdev->scsi_level < SCSI_SPC_5) { 641 sdev->cdl_supported = 0; 642 return; 643 } 644 645 buf = kmalloc(SCSI_CDL_CHECK_BUF_LEN, GFP_KERNEL); 646 if (!buf) { 647 sdev->cdl_supported = 0; 648 return; 649 } 650 651 /* Check support for READ_16, WRITE_16, READ_32 and WRITE_32 commands */ 652 cdl_supported = 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); 657 if (cdl_supported) { 658 /* 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. 662 */ 663 sdev->use_16_for_rw = 1; 664 sdev->use_10_for_rw = 0; 665 666 sdev->cdl_supported = 1; 667 } else { 668 sdev->cdl_supported = 0; 669 } 670 671 kfree(buf); 672 } 673 674 /** 675 * scsi_cdl_enable - Enable or disable a SCSI device supports for Command 676 * Duration Limits 677 * @sdev: The target device 678 * @enable: the target state 679 */ 680 int scsi_cdl_enable(struct scsi_device *sdev, bool enable) 681 { 682 struct scsi_mode_data data; 683 struct scsi_sense_hdr sshdr; 684 struct scsi_vpd *vpd; 685 bool is_ata = false; 686 char buf[64]; 687 int ret; 688 689 if (!sdev->cdl_supported) 690 return -EOPNOTSUPP; 691 692 rcu_read_lock(); 693 vpd = rcu_dereference(sdev->vpd_pg89); 694 if (vpd) 695 is_ata = true; 696 rcu_read_unlock(); 697 698 /* 699 * For ATA devices, CDL needs to be enabled with a SET FEATURES command. 700 */ 701 if (is_ata) { 702 char *buf_data; 703 int len; 704 705 ret = scsi_mode_sense(sdev, 0x08, 0x0a, 0xf2, buf, sizeof(buf), 706 5 * HZ, 3, &data, NULL); 707 if (ret) 708 return -EINVAL; 709 710 /* 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; 716 if (enable) 717 buf_data[4] = 0x02; 718 else 719 buf_data[4] = 0; 720 721 ret = scsi_mode_select(sdev, 1, 0, buf_data, len, 5 * HZ, 3, 722 &data, &sshdr); 723 if (ret) { 724 if (scsi_sense_valid(&sshdr)) 725 scsi_print_sense_hdr(sdev, 726 dev_name(&sdev->sdev_gendev), &sshdr); 727 return ret; 728 } 729 } 730 731 sdev->cdl_enable = enable; 732 733 return 0; 734 } 735 736 /** 737 * scsi_device_get - get an additional reference to a scsi_device 738 * @sdev: device to get a reference to 739 * 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. 743 * 744 * This will fail if a device is deleted or cancelled, or when the LLD module 745 * is in the process of being unloaded. 746 */ 747 int scsi_device_get(struct scsi_device *sdev) 748 { 749 if (sdev->sdev_state == SDEV_DEL || sdev->sdev_state == SDEV_CANCEL) 750 goto fail; 751 if (!try_module_get(sdev->host->hostt->module)) 752 goto fail; 753 if (!get_device(&sdev->sdev_gendev)) 754 goto fail_put_module; 755 return 0; 756 757 fail_put_module: 758 module_put(sdev->host->hostt->module); 759 fail: 760 return -ENXIO; 761 } 762 EXPORT_SYMBOL(scsi_device_get); 763 764 /** 765 * scsi_device_put - release a reference to a scsi_device 766 * @sdev: device to release a reference on. 767 * 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 770 * user vanishes. 771 */ 772 void scsi_device_put(struct scsi_device *sdev) 773 { 774 struct module *mod = sdev->host->hostt->module; 775 776 put_device(&sdev->sdev_gendev); 777 module_put(mod); 778 } 779 EXPORT_SYMBOL(scsi_device_put); 780 781 /* 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) 784 { 785 struct list_head *list = (prev ? &prev->siblings : &shost->__devices); 786 struct scsi_device *next = NULL; 787 unsigned long flags; 788 789 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)) 794 break; 795 next = NULL; 796 list = list->next; 797 } 798 spin_unlock_irqrestore(shost->host_lock, flags); 799 800 if (prev) 801 scsi_device_put(prev); 802 return next; 803 } 804 EXPORT_SYMBOL(__scsi_iterate_devices); 805 806 /** 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 811 * 812 * This traverses over each device of @starget. The devices have 813 * a reference that must be released by scsi_host_put when breaking 814 * out of the loop. 815 */ 816 void starget_for_each_device(struct scsi_target *starget, void *data, 817 void (*fn)(struct scsi_device *, void *)) 818 { 819 struct Scsi_Host *shost = dev_to_shost(starget->dev.parent); 820 struct scsi_device *sdev; 821 822 shost_for_each_device(sdev, shost) { 823 if ((sdev->channel == starget->channel) && 824 (sdev->id == starget->id)) 825 fn(sdev, data); 826 } 827 } 828 EXPORT_SYMBOL(starget_for_each_device); 829 830 /** 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 835 * 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. 839 * 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. 843 **/ 844 void __starget_for_each_device(struct scsi_target *starget, void *data, 845 void (*fn)(struct scsi_device *, void *)) 846 { 847 struct Scsi_Host *shost = dev_to_shost(starget->dev.parent); 848 struct scsi_device *sdev; 849 850 __shost_for_each_device(sdev, shost) { 851 if ((sdev->channel == starget->channel) && 852 (sdev->id == starget->id)) 853 fn(sdev, data); 854 } 855 } 856 EXPORT_SYMBOL(__starget_for_each_device); 857 858 /** 859 * __scsi_device_lookup_by_target - find a device given the target (UNLOCKED) 860 * @starget: SCSI target pointer 861 * @lun: SCSI Logical Unit Number 862 * 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. 868 * 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. 872 **/ 873 struct scsi_device *__scsi_device_lookup_by_target(struct scsi_target *starget, 874 u64 lun) 875 { 876 struct scsi_device *sdev; 877 878 list_for_each_entry(sdev, &starget->devices, same_target_siblings) { 879 if (sdev->sdev_state == SDEV_DEL) 880 continue; 881 if (sdev->lun ==lun) 882 return sdev; 883 } 884 885 return NULL; 886 } 887 EXPORT_SYMBOL(__scsi_device_lookup_by_target); 888 889 /** 890 * scsi_device_lookup_by_target - find a device given the target 891 * @starget: SCSI target pointer 892 * @lun: SCSI Logical Unit Number 893 * 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. 897 **/ 898 struct scsi_device *scsi_device_lookup_by_target(struct scsi_target *starget, 899 u64 lun) 900 { 901 struct scsi_device *sdev; 902 struct Scsi_Host *shost = dev_to_shost(starget->dev.parent); 903 unsigned long flags; 904 905 spin_lock_irqsave(shost->host_lock, flags); 906 sdev = __scsi_device_lookup_by_target(starget, lun); 907 if (sdev && scsi_device_get(sdev)) 908 sdev = NULL; 909 spin_unlock_irqrestore(shost->host_lock, flags); 910 911 return sdev; 912 } 913 EXPORT_SYMBOL(scsi_device_lookup_by_target); 914 915 /** 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 921 * 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. 926 * 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. 930 **/ 931 struct scsi_device *__scsi_device_lookup(struct Scsi_Host *shost, 932 uint channel, uint id, u64 lun) 933 { 934 struct scsi_device *sdev; 935 936 list_for_each_entry(sdev, &shost->__devices, siblings) { 937 if (sdev->sdev_state == SDEV_DEL) 938 continue; 939 if (sdev->channel == channel && sdev->id == id && 940 sdev->lun ==lun) 941 return sdev; 942 } 943 944 return NULL; 945 } 946 EXPORT_SYMBOL(__scsi_device_lookup); 947 948 /** 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 954 * 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. 958 **/ 959 struct scsi_device *scsi_device_lookup(struct Scsi_Host *shost, 960 uint channel, uint id, u64 lun) 961 { 962 struct scsi_device *sdev; 963 unsigned long flags; 964 965 spin_lock_irqsave(shost->host_lock, flags); 966 sdev = __scsi_device_lookup(shost, channel, id, lun); 967 if (sdev && scsi_device_get(sdev)) 968 sdev = NULL; 969 spin_unlock_irqrestore(shost->host_lock, flags); 970 971 return sdev; 972 } 973 EXPORT_SYMBOL(scsi_device_lookup); 974 975 MODULE_DESCRIPTION("SCSI core"); 976 MODULE_LICENSE("GPL"); 977 978 module_param(scsi_logging_level, int, S_IRUGO|S_IWUSR); 979 MODULE_PARM_DESC(scsi_logging_level, "a bit mask of logging levels"); 980 981 static int __init init_scsi(void) 982 { 983 int error; 984 985 error = scsi_init_procfs(); 986 if (error) 987 goto cleanup_queue; 988 error = scsi_init_devinfo(); 989 if (error) 990 goto cleanup_procfs; 991 error = scsi_init_hosts(); 992 if (error) 993 goto cleanup_devlist; 994 error = scsi_init_sysctl(); 995 if (error) 996 goto cleanup_hosts; 997 error = scsi_sysfs_register(); 998 if (error) 999 goto cleanup_sysctl; 1000 1001 scsi_netlink_init(); 1002 1003 printk(KERN_NOTICE "SCSI subsystem initialized\n"); 1004 return 0; 1005 1006 cleanup_sysctl: 1007 scsi_exit_sysctl(); 1008 cleanup_hosts: 1009 scsi_exit_hosts(); 1010 cleanup_devlist: 1011 scsi_exit_devinfo(); 1012 cleanup_procfs: 1013 scsi_exit_procfs(); 1014 cleanup_queue: 1015 scsi_exit_queue(); 1016 printk(KERN_ERR "SCSI subsystem failed to initialize, error = %d\n", 1017 -error); 1018 return error; 1019 } 1020 1021 static void __exit exit_scsi(void) 1022 { 1023 scsi_netlink_exit(); 1024 scsi_sysfs_unregister(); 1025 scsi_exit_sysctl(); 1026 scsi_exit_hosts(); 1027 scsi_exit_devinfo(); 1028 scsi_exit_procfs(); 1029 scsi_exit_queue(); 1030 } 1031 1032 subsys_initcall(init_scsi); 1033 module_exit(exit_scsi); 1034