1 /* 2 * scsi.c Copyright (C) 1992 Drew Eckhardt 3 * Copyright (C) 1993, 1994, 1995, 1999 Eric Youngdale 4 * Copyright (C) 2002, 2003 Christoph Hellwig 5 * 6 * generic mid-level SCSI driver 7 * Initial versions: Drew Eckhardt 8 * Subsequent revisions: Eric Youngdale 9 * 10 * <drew@colorado.edu> 11 * 12 * Bug correction thanks go to : 13 * Rik Faith <faith@cs.unc.edu> 14 * Tommy Thorn <tthorn> 15 * Thomas Wuensche <tw@fgb1.fgb.mw.tu-muenchen.de> 16 * 17 * Modified by Eric Youngdale eric@andante.org or ericy@gnu.ai.mit.edu to 18 * add scatter-gather, multiple outstanding request, and other 19 * enhancements. 20 * 21 * Native multichannel, wide scsi, /proc/scsi and hot plugging 22 * support added by Michael Neuffer <mike@i-connect.net> 23 * 24 * Added request_module("scsi_hostadapter") for kerneld: 25 * (Put an "alias scsi_hostadapter your_hostadapter" in /etc/modprobe.conf) 26 * Bjorn Ekwall <bj0rn@blox.se> 27 * (changed to kmod) 28 * 29 * Major improvements to the timeout, abort, and reset processing, 30 * as well as performance modifications for large queue depths by 31 * Leonard N. Zubkoff <lnz@dandelion.com> 32 * 33 * Converted cli() code to spinlocks, Ingo Molnar 34 * 35 * Jiffies wrap fixes (host->resetting), 3 Dec 1998 Andrea Arcangeli 36 * 37 * out_of_space hacks, D. Gilbert (dpg) 990608 38 */ 39 40 #include <linux/module.h> 41 #include <linux/moduleparam.h> 42 #include <linux/kernel.h> 43 #include <linux/timer.h> 44 #include <linux/string.h> 45 #include <linux/slab.h> 46 #include <linux/blkdev.h> 47 #include <linux/delay.h> 48 #include <linux/init.h> 49 #include <linux/completion.h> 50 #include <linux/unistd.h> 51 #include <linux/spinlock.h> 52 #include <linux/kmod.h> 53 #include <linux/interrupt.h> 54 #include <linux/notifier.h> 55 #include <linux/cpu.h> 56 #include <linux/mutex.h> 57 #include <linux/async.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 /* sd, scsi core and power management need to coordinate flushing async actions */ 89 ASYNC_DOMAIN(scsi_sd_probe_domain); 90 EXPORT_SYMBOL(scsi_sd_probe_domain); 91 92 /* 93 * Separate domain (from scsi_sd_probe_domain) to maximize the benefit of 94 * asynchronous system resume operations. It is marked 'exclusive' to avoid 95 * being included in the async_synchronize_full() that is invoked by 96 * dpm_resume() 97 */ 98 ASYNC_DOMAIN_EXCLUSIVE(scsi_sd_pm_domain); 99 EXPORT_SYMBOL(scsi_sd_pm_domain); 100 101 /** 102 * scsi_put_command - Free a scsi command block 103 * @cmd: command block to free 104 * 105 * Returns: Nothing. 106 * 107 * Notes: The command must not belong to any lists. 108 */ 109 void scsi_put_command(struct scsi_cmnd *cmd) 110 { 111 scsi_del_cmd_from_list(cmd); 112 BUG_ON(delayed_work_pending(&cmd->abort_work)); 113 } 114 115 #ifdef CONFIG_SCSI_LOGGING 116 void scsi_log_send(struct scsi_cmnd *cmd) 117 { 118 unsigned int level; 119 120 /* 121 * If ML QUEUE log level is greater than or equal to: 122 * 123 * 1: nothing (match completion) 124 * 125 * 2: log opcode + command of all commands + cmd address 126 * 127 * 3: same as 2 128 * 129 * 4: same as 3 130 */ 131 if (unlikely(scsi_logging_level)) { 132 level = SCSI_LOG_LEVEL(SCSI_LOG_MLQUEUE_SHIFT, 133 SCSI_LOG_MLQUEUE_BITS); 134 if (level > 1) { 135 scmd_printk(KERN_INFO, cmd, 136 "Send: scmd 0x%p\n", cmd); 137 scsi_print_command(cmd); 138 } 139 } 140 } 141 142 void scsi_log_completion(struct scsi_cmnd *cmd, int disposition) 143 { 144 unsigned int level; 145 146 /* 147 * If ML COMPLETE log level is greater than or equal to: 148 * 149 * 1: log disposition, result, opcode + command, and conditionally 150 * sense data for failures or non SUCCESS dispositions. 151 * 152 * 2: same as 1 but for all command completions. 153 * 154 * 3: same as 2 155 * 156 * 4: same as 3 plus dump extra junk 157 */ 158 if (unlikely(scsi_logging_level)) { 159 level = SCSI_LOG_LEVEL(SCSI_LOG_MLCOMPLETE_SHIFT, 160 SCSI_LOG_MLCOMPLETE_BITS); 161 if (((level > 0) && (cmd->result || disposition != SUCCESS)) || 162 (level > 1)) { 163 scsi_print_result(cmd, "Done", disposition); 164 scsi_print_command(cmd); 165 if (status_byte(cmd->result) & CHECK_CONDITION) 166 scsi_print_sense(cmd); 167 if (level > 3) 168 scmd_printk(KERN_INFO, cmd, 169 "scsi host busy %d failed %d\n", 170 atomic_read(&cmd->device->host->host_busy), 171 cmd->device->host->host_failed); 172 } 173 } 174 } 175 #endif 176 177 /** 178 * scsi_cmd_get_serial - Assign a serial number to a command 179 * @host: the scsi host 180 * @cmd: command to assign serial number to 181 * 182 * Description: a serial number identifies a request for error recovery 183 * and debugging purposes. Protected by the Host_Lock of host. 184 */ 185 void scsi_cmd_get_serial(struct Scsi_Host *host, struct scsi_cmnd *cmd) 186 { 187 cmd->serial_number = host->cmd_serial_number++; 188 if (cmd->serial_number == 0) 189 cmd->serial_number = host->cmd_serial_number++; 190 } 191 EXPORT_SYMBOL(scsi_cmd_get_serial); 192 193 /** 194 * scsi_finish_command - cleanup and pass command back to upper layer 195 * @cmd: the command 196 * 197 * Description: Pass command off to upper layer for finishing of I/O 198 * request, waking processes that are waiting on results, 199 * etc. 200 */ 201 void scsi_finish_command(struct scsi_cmnd *cmd) 202 { 203 struct scsi_device *sdev = cmd->device; 204 struct scsi_target *starget = scsi_target(sdev); 205 struct Scsi_Host *shost = sdev->host; 206 struct scsi_driver *drv; 207 unsigned int good_bytes; 208 209 scsi_device_unbusy(sdev); 210 211 /* 212 * Clear the flags that say that the device/target/host is no longer 213 * capable of accepting new commands. 214 */ 215 if (atomic_read(&shost->host_blocked)) 216 atomic_set(&shost->host_blocked, 0); 217 if (atomic_read(&starget->target_blocked)) 218 atomic_set(&starget->target_blocked, 0); 219 if (atomic_read(&sdev->device_blocked)) 220 atomic_set(&sdev->device_blocked, 0); 221 222 /* 223 * If we have valid sense information, then some kind of recovery 224 * must have taken place. Make a note of this. 225 */ 226 if (SCSI_SENSE_VALID(cmd)) 227 cmd->result |= (DRIVER_SENSE << 24); 228 229 SCSI_LOG_MLCOMPLETE(4, sdev_printk(KERN_INFO, sdev, 230 "Notifying upper driver of completion " 231 "(result %x)\n", cmd->result)); 232 233 good_bytes = scsi_bufflen(cmd); 234 if (!blk_rq_is_passthrough(cmd->request)) { 235 int old_good_bytes = good_bytes; 236 drv = scsi_cmd_to_driver(cmd); 237 if (drv->done) 238 good_bytes = drv->done(cmd); 239 /* 240 * USB may not give sense identifying bad sector and 241 * simply return a residue instead, so subtract off the 242 * residue if drv->done() error processing indicates no 243 * change to the completion length. 244 */ 245 if (good_bytes == old_good_bytes) 246 good_bytes -= scsi_get_resid(cmd); 247 } 248 scsi_io_completion(cmd, good_bytes); 249 } 250 251 /** 252 * scsi_change_queue_depth - change a device's queue depth 253 * @sdev: SCSI Device in question 254 * @depth: number of commands allowed to be queued to the driver 255 * 256 * Sets the device queue depth and returns the new value. 257 */ 258 int scsi_change_queue_depth(struct scsi_device *sdev, int depth) 259 { 260 if (depth > 0) { 261 sdev->queue_depth = depth; 262 wmb(); 263 } 264 265 if (sdev->request_queue) 266 blk_set_queue_depth(sdev->request_queue, depth); 267 268 return sdev->queue_depth; 269 } 270 EXPORT_SYMBOL(scsi_change_queue_depth); 271 272 /** 273 * scsi_track_queue_full - track QUEUE_FULL events to adjust queue depth 274 * @sdev: SCSI Device in question 275 * @depth: Current number of outstanding SCSI commands on this device, 276 * not counting the one returned as QUEUE_FULL. 277 * 278 * Description: This function will track successive QUEUE_FULL events on a 279 * specific SCSI device to determine if and when there is a 280 * need to adjust the queue depth on the device. 281 * 282 * Returns: 0 - No change needed, >0 - Adjust queue depth to this new depth, 283 * -1 - Drop back to untagged operation using host->cmd_per_lun 284 * as the untagged command depth 285 * 286 * Lock Status: None held on entry 287 * 288 * Notes: Low level drivers may call this at any time and we will do 289 * "The Right Thing." We are interrupt context safe. 290 */ 291 int scsi_track_queue_full(struct scsi_device *sdev, int depth) 292 { 293 294 /* 295 * Don't let QUEUE_FULLs on the same 296 * jiffies count, they could all be from 297 * same event. 298 */ 299 if ((jiffies >> 4) == (sdev->last_queue_full_time >> 4)) 300 return 0; 301 302 sdev->last_queue_full_time = jiffies; 303 if (sdev->last_queue_full_depth != depth) { 304 sdev->last_queue_full_count = 1; 305 sdev->last_queue_full_depth = depth; 306 } else { 307 sdev->last_queue_full_count++; 308 } 309 310 if (sdev->last_queue_full_count <= 10) 311 return 0; 312 313 return scsi_change_queue_depth(sdev, depth); 314 } 315 EXPORT_SYMBOL(scsi_track_queue_full); 316 317 /** 318 * scsi_vpd_inquiry - Request a device provide us with a VPD page 319 * @sdev: The device to ask 320 * @buffer: Where to put the result 321 * @page: Which Vital Product Data to return 322 * @len: The length of the buffer 323 * 324 * This is an internal helper function. You probably want to use 325 * scsi_get_vpd_page instead. 326 * 327 * Returns size of the vpd page on success or a negative error number. 328 */ 329 static int scsi_vpd_inquiry(struct scsi_device *sdev, unsigned char *buffer, 330 u8 page, unsigned len) 331 { 332 int result; 333 unsigned char cmd[16]; 334 335 if (len < 4) 336 return -EINVAL; 337 338 cmd[0] = INQUIRY; 339 cmd[1] = 1; /* EVPD */ 340 cmd[2] = page; 341 cmd[3] = len >> 8; 342 cmd[4] = len & 0xff; 343 cmd[5] = 0; /* Control byte */ 344 345 /* 346 * I'm not convinced we need to try quite this hard to get VPD, but 347 * all the existing users tried this hard. 348 */ 349 result = scsi_execute_req(sdev, cmd, DMA_FROM_DEVICE, buffer, 350 len, NULL, 30 * HZ, 3, NULL); 351 if (result) 352 return -EIO; 353 354 /* Sanity check that we got the page back that we asked for */ 355 if (buffer[1] != page) 356 return -EIO; 357 358 return get_unaligned_be16(&buffer[2]) + 4; 359 } 360 361 /** 362 * scsi_get_vpd_page - Get Vital Product Data from a SCSI device 363 * @sdev: The device to ask 364 * @page: Which Vital Product Data to return 365 * @buf: where to store the VPD 366 * @buf_len: number of bytes in the VPD buffer area 367 * 368 * SCSI devices may optionally supply Vital Product Data. Each 'page' 369 * of VPD is defined in the appropriate SCSI document (eg SPC, SBC). 370 * If the device supports this VPD page, this routine returns a pointer 371 * to a buffer containing the data from that page. The caller is 372 * responsible for calling kfree() on this pointer when it is no longer 373 * needed. If we cannot retrieve the VPD page this routine returns %NULL. 374 */ 375 int scsi_get_vpd_page(struct scsi_device *sdev, u8 page, unsigned char *buf, 376 int buf_len) 377 { 378 int i, result; 379 380 if (sdev->skip_vpd_pages) 381 goto fail; 382 383 /* Ask for all the pages supported by this device */ 384 result = scsi_vpd_inquiry(sdev, buf, 0, buf_len); 385 if (result < 4) 386 goto fail; 387 388 /* If the user actually wanted this page, we can skip the rest */ 389 if (page == 0) 390 return 0; 391 392 for (i = 4; i < min(result, buf_len); i++) 393 if (buf[i] == page) 394 goto found; 395 396 if (i < result && i >= buf_len) 397 /* ran off the end of the buffer, give us benefit of doubt */ 398 goto found; 399 /* The device claims it doesn't support the requested page */ 400 goto fail; 401 402 found: 403 result = scsi_vpd_inquiry(sdev, buf, page, buf_len); 404 if (result < 0) 405 goto fail; 406 407 return 0; 408 409 fail: 410 return -EINVAL; 411 } 412 EXPORT_SYMBOL_GPL(scsi_get_vpd_page); 413 414 /** 415 * scsi_get_vpd_buf - Get Vital Product Data from a SCSI device 416 * @sdev: The device to ask 417 * @page: Which Vital Product Data to return 418 * 419 * Returns %NULL upon failure. 420 */ 421 static struct scsi_vpd *scsi_get_vpd_buf(struct scsi_device *sdev, u8 page) 422 { 423 struct scsi_vpd *vpd_buf; 424 int vpd_len = SCSI_VPD_PG_LEN, result; 425 426 retry_pg: 427 vpd_buf = kmalloc(sizeof(*vpd_buf) + vpd_len, GFP_KERNEL); 428 if (!vpd_buf) 429 return NULL; 430 431 result = scsi_vpd_inquiry(sdev, vpd_buf->data, page, vpd_len); 432 if (result < 0) { 433 kfree(vpd_buf); 434 return NULL; 435 } 436 if (result > vpd_len) { 437 vpd_len = result; 438 kfree(vpd_buf); 439 goto retry_pg; 440 } 441 442 vpd_buf->len = result; 443 444 return vpd_buf; 445 } 446 447 static void scsi_update_vpd_page(struct scsi_device *sdev, u8 page, 448 struct scsi_vpd __rcu **sdev_vpd_buf) 449 { 450 struct scsi_vpd *vpd_buf; 451 452 vpd_buf = scsi_get_vpd_buf(sdev, page); 453 if (!vpd_buf) 454 return; 455 456 mutex_lock(&sdev->inquiry_mutex); 457 rcu_swap_protected(*sdev_vpd_buf, vpd_buf, 458 lockdep_is_held(&sdev->inquiry_mutex)); 459 mutex_unlock(&sdev->inquiry_mutex); 460 461 if (vpd_buf) 462 kfree_rcu(vpd_buf, rcu); 463 } 464 465 /** 466 * scsi_attach_vpd - Attach Vital Product Data to a SCSI device structure 467 * @sdev: The device to ask 468 * 469 * Attach the 'Device Identification' VPD page (0x83) and the 470 * 'Unit Serial Number' VPD page (0x80) to a SCSI device 471 * structure. This information can be used to identify the device 472 * uniquely. 473 */ 474 void scsi_attach_vpd(struct scsi_device *sdev) 475 { 476 int i; 477 struct scsi_vpd *vpd_buf; 478 479 if (!scsi_device_supports_vpd(sdev)) 480 return; 481 482 /* Ask for all the pages supported by this device */ 483 vpd_buf = scsi_get_vpd_buf(sdev, 0); 484 if (!vpd_buf) 485 return; 486 487 for (i = 4; i < vpd_buf->len; i++) { 488 if (vpd_buf->data[i] == 0x80) 489 scsi_update_vpd_page(sdev, 0x80, &sdev->vpd_pg80); 490 if (vpd_buf->data[i] == 0x83) 491 scsi_update_vpd_page(sdev, 0x83, &sdev->vpd_pg83); 492 } 493 kfree(vpd_buf); 494 } 495 496 /** 497 * scsi_report_opcode - Find out if a given command opcode is supported 498 * @sdev: scsi device to query 499 * @buffer: scratch buffer (must be at least 20 bytes long) 500 * @len: length of buffer 501 * @opcode: opcode for command to look up 502 * 503 * Uses the REPORT SUPPORTED OPERATION CODES to look up the given 504 * opcode. Returns -EINVAL if RSOC fails, 0 if the command opcode is 505 * unsupported and 1 if the device claims to support the command. 506 */ 507 int scsi_report_opcode(struct scsi_device *sdev, unsigned char *buffer, 508 unsigned int len, unsigned char opcode) 509 { 510 unsigned char cmd[16]; 511 struct scsi_sense_hdr sshdr; 512 int result; 513 514 if (sdev->no_report_opcodes || sdev->scsi_level < SCSI_SPC_3) 515 return -EINVAL; 516 517 memset(cmd, 0, 16); 518 cmd[0] = MAINTENANCE_IN; 519 cmd[1] = MI_REPORT_SUPPORTED_OPERATION_CODES; 520 cmd[2] = 1; /* One command format */ 521 cmd[3] = opcode; 522 put_unaligned_be32(len, &cmd[6]); 523 memset(buffer, 0, len); 524 525 result = scsi_execute_req(sdev, cmd, DMA_FROM_DEVICE, buffer, len, 526 &sshdr, 30 * HZ, 3, NULL); 527 528 if (result && scsi_sense_valid(&sshdr) && 529 sshdr.sense_key == ILLEGAL_REQUEST && 530 (sshdr.asc == 0x20 || sshdr.asc == 0x24) && sshdr.ascq == 0x00) 531 return -EINVAL; 532 533 if ((buffer[1] & 3) == 3) /* Command supported */ 534 return 1; 535 536 return 0; 537 } 538 EXPORT_SYMBOL(scsi_report_opcode); 539 540 /** 541 * scsi_device_get - get an additional reference to a scsi_device 542 * @sdev: device to get a reference to 543 * 544 * Description: Gets a reference to the scsi_device and increments the use count 545 * of the underlying LLDD module. You must hold host_lock of the 546 * parent Scsi_Host or already have a reference when calling this. 547 * 548 * This will fail if a device is deleted or cancelled, or when the LLD module 549 * is in the process of being unloaded. 550 */ 551 int scsi_device_get(struct scsi_device *sdev) 552 { 553 if (sdev->sdev_state == SDEV_DEL || sdev->sdev_state == SDEV_CANCEL) 554 goto fail; 555 if (!get_device(&sdev->sdev_gendev)) 556 goto fail; 557 if (!try_module_get(sdev->host->hostt->module)) 558 goto fail_put_device; 559 return 0; 560 561 fail_put_device: 562 put_device(&sdev->sdev_gendev); 563 fail: 564 return -ENXIO; 565 } 566 EXPORT_SYMBOL(scsi_device_get); 567 568 /** 569 * scsi_device_put - release a reference to a scsi_device 570 * @sdev: device to release a reference on. 571 * 572 * Description: Release a reference to the scsi_device and decrements the use 573 * count of the underlying LLDD module. The device is freed once the last 574 * user vanishes. 575 */ 576 void scsi_device_put(struct scsi_device *sdev) 577 { 578 module_put(sdev->host->hostt->module); 579 put_device(&sdev->sdev_gendev); 580 } 581 EXPORT_SYMBOL(scsi_device_put); 582 583 /* helper for shost_for_each_device, see that for documentation */ 584 struct scsi_device *__scsi_iterate_devices(struct Scsi_Host *shost, 585 struct scsi_device *prev) 586 { 587 struct list_head *list = (prev ? &prev->siblings : &shost->__devices); 588 struct scsi_device *next = NULL; 589 unsigned long flags; 590 591 spin_lock_irqsave(shost->host_lock, flags); 592 while (list->next != &shost->__devices) { 593 next = list_entry(list->next, struct scsi_device, siblings); 594 /* skip devices that we can't get a reference to */ 595 if (!scsi_device_get(next)) 596 break; 597 next = NULL; 598 list = list->next; 599 } 600 spin_unlock_irqrestore(shost->host_lock, flags); 601 602 if (prev) 603 scsi_device_put(prev); 604 return next; 605 } 606 EXPORT_SYMBOL(__scsi_iterate_devices); 607 608 /** 609 * starget_for_each_device - helper to walk all devices of a target 610 * @starget: target whose devices we want to iterate over. 611 * @data: Opaque passed to each function call. 612 * @fn: Function to call on each device 613 * 614 * This traverses over each device of @starget. The devices have 615 * a reference that must be released by scsi_host_put when breaking 616 * out of the loop. 617 */ 618 void starget_for_each_device(struct scsi_target *starget, void *data, 619 void (*fn)(struct scsi_device *, void *)) 620 { 621 struct Scsi_Host *shost = dev_to_shost(starget->dev.parent); 622 struct scsi_device *sdev; 623 624 shost_for_each_device(sdev, shost) { 625 if ((sdev->channel == starget->channel) && 626 (sdev->id == starget->id)) 627 fn(sdev, data); 628 } 629 } 630 EXPORT_SYMBOL(starget_for_each_device); 631 632 /** 633 * __starget_for_each_device - helper to walk all devices of a target (UNLOCKED) 634 * @starget: target whose devices we want to iterate over. 635 * @data: parameter for callback @fn() 636 * @fn: callback function that is invoked for each device 637 * 638 * This traverses over each device of @starget. It does _not_ 639 * take a reference on the scsi_device, so the whole loop must be 640 * protected by shost->host_lock. 641 * 642 * Note: The only reason why drivers would want to use this is because 643 * they need to access the device list in irq context. Otherwise you 644 * really want to use starget_for_each_device instead. 645 **/ 646 void __starget_for_each_device(struct scsi_target *starget, void *data, 647 void (*fn)(struct scsi_device *, void *)) 648 { 649 struct Scsi_Host *shost = dev_to_shost(starget->dev.parent); 650 struct scsi_device *sdev; 651 652 __shost_for_each_device(sdev, shost) { 653 if ((sdev->channel == starget->channel) && 654 (sdev->id == starget->id)) 655 fn(sdev, data); 656 } 657 } 658 EXPORT_SYMBOL(__starget_for_each_device); 659 660 /** 661 * __scsi_device_lookup_by_target - find a device given the target (UNLOCKED) 662 * @starget: SCSI target pointer 663 * @lun: SCSI Logical Unit Number 664 * 665 * Description: Looks up the scsi_device with the specified @lun for a given 666 * @starget. The returned scsi_device does not have an additional 667 * reference. You must hold the host's host_lock over this call and 668 * any access to the returned scsi_device. A scsi_device in state 669 * SDEV_DEL is skipped. 670 * 671 * Note: The only reason why drivers should use this is because 672 * they need to access the device list in irq context. Otherwise you 673 * really want to use scsi_device_lookup_by_target instead. 674 **/ 675 struct scsi_device *__scsi_device_lookup_by_target(struct scsi_target *starget, 676 u64 lun) 677 { 678 struct scsi_device *sdev; 679 680 list_for_each_entry(sdev, &starget->devices, same_target_siblings) { 681 if (sdev->sdev_state == SDEV_DEL) 682 continue; 683 if (sdev->lun ==lun) 684 return sdev; 685 } 686 687 return NULL; 688 } 689 EXPORT_SYMBOL(__scsi_device_lookup_by_target); 690 691 /** 692 * scsi_device_lookup_by_target - find a device given the target 693 * @starget: SCSI target pointer 694 * @lun: SCSI Logical Unit Number 695 * 696 * Description: Looks up the scsi_device with the specified @lun for a given 697 * @starget. The returned scsi_device has an additional reference that 698 * needs to be released with scsi_device_put once you're done with it. 699 **/ 700 struct scsi_device *scsi_device_lookup_by_target(struct scsi_target *starget, 701 u64 lun) 702 { 703 struct scsi_device *sdev; 704 struct Scsi_Host *shost = dev_to_shost(starget->dev.parent); 705 unsigned long flags; 706 707 spin_lock_irqsave(shost->host_lock, flags); 708 sdev = __scsi_device_lookup_by_target(starget, lun); 709 if (sdev && scsi_device_get(sdev)) 710 sdev = NULL; 711 spin_unlock_irqrestore(shost->host_lock, flags); 712 713 return sdev; 714 } 715 EXPORT_SYMBOL(scsi_device_lookup_by_target); 716 717 /** 718 * __scsi_device_lookup - find a device given the host (UNLOCKED) 719 * @shost: SCSI host pointer 720 * @channel: SCSI channel (zero if only one channel) 721 * @id: SCSI target number (physical unit number) 722 * @lun: SCSI Logical Unit Number 723 * 724 * Description: Looks up the scsi_device with the specified @channel, @id, @lun 725 * for a given host. The returned scsi_device does not have an additional 726 * reference. You must hold the host's host_lock over this call and any access 727 * to the returned scsi_device. 728 * 729 * Note: The only reason why drivers would want to use this is because 730 * they need to access the device list in irq context. Otherwise you 731 * really want to use scsi_device_lookup instead. 732 **/ 733 struct scsi_device *__scsi_device_lookup(struct Scsi_Host *shost, 734 uint channel, uint id, u64 lun) 735 { 736 struct scsi_device *sdev; 737 738 list_for_each_entry(sdev, &shost->__devices, siblings) { 739 if (sdev->sdev_state == SDEV_DEL) 740 continue; 741 if (sdev->channel == channel && sdev->id == id && 742 sdev->lun ==lun) 743 return sdev; 744 } 745 746 return NULL; 747 } 748 EXPORT_SYMBOL(__scsi_device_lookup); 749 750 /** 751 * scsi_device_lookup - find a device given the host 752 * @shost: SCSI host pointer 753 * @channel: SCSI channel (zero if only one channel) 754 * @id: SCSI target number (physical unit number) 755 * @lun: SCSI Logical Unit Number 756 * 757 * Description: Looks up the scsi_device with the specified @channel, @id, @lun 758 * for a given host. The returned scsi_device has an additional reference that 759 * needs to be released with scsi_device_put once you're done with it. 760 **/ 761 struct scsi_device *scsi_device_lookup(struct Scsi_Host *shost, 762 uint channel, uint id, u64 lun) 763 { 764 struct scsi_device *sdev; 765 unsigned long flags; 766 767 spin_lock_irqsave(shost->host_lock, flags); 768 sdev = __scsi_device_lookup(shost, channel, id, lun); 769 if (sdev && scsi_device_get(sdev)) 770 sdev = NULL; 771 spin_unlock_irqrestore(shost->host_lock, flags); 772 773 return sdev; 774 } 775 EXPORT_SYMBOL(scsi_device_lookup); 776 777 MODULE_DESCRIPTION("SCSI core"); 778 MODULE_LICENSE("GPL"); 779 780 module_param(scsi_logging_level, int, S_IRUGO|S_IWUSR); 781 MODULE_PARM_DESC(scsi_logging_level, "a bit mask of logging levels"); 782 783 #ifdef CONFIG_SCSI_MQ_DEFAULT 784 bool scsi_use_blk_mq = true; 785 #else 786 bool scsi_use_blk_mq = false; 787 #endif 788 module_param_named(use_blk_mq, scsi_use_blk_mq, bool, S_IWUSR | S_IRUGO); 789 790 static int __init init_scsi(void) 791 { 792 int error; 793 794 error = scsi_init_queue(); 795 if (error) 796 return error; 797 error = scsi_init_procfs(); 798 if (error) 799 goto cleanup_queue; 800 error = scsi_init_devinfo(); 801 if (error) 802 goto cleanup_procfs; 803 error = scsi_init_hosts(); 804 if (error) 805 goto cleanup_devlist; 806 error = scsi_init_sysctl(); 807 if (error) 808 goto cleanup_hosts; 809 error = scsi_sysfs_register(); 810 if (error) 811 goto cleanup_sysctl; 812 813 scsi_netlink_init(); 814 815 printk(KERN_NOTICE "SCSI subsystem initialized\n"); 816 return 0; 817 818 cleanup_sysctl: 819 scsi_exit_sysctl(); 820 cleanup_hosts: 821 scsi_exit_hosts(); 822 cleanup_devlist: 823 scsi_exit_devinfo(); 824 cleanup_procfs: 825 scsi_exit_procfs(); 826 cleanup_queue: 827 scsi_exit_queue(); 828 printk(KERN_ERR "SCSI subsystem failed to initialize, error = %d\n", 829 -error); 830 return error; 831 } 832 833 static void __exit exit_scsi(void) 834 { 835 scsi_netlink_exit(); 836 scsi_sysfs_unregister(); 837 scsi_exit_sysctl(); 838 scsi_exit_hosts(); 839 scsi_exit_devinfo(); 840 scsi_exit_procfs(); 841 scsi_exit_queue(); 842 async_unregister_domain(&scsi_sd_probe_domain); 843 } 844 845 subsys_initcall(init_scsi); 846 module_exit(exit_scsi); 847