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 * 1024 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, 1024); 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_req(sdev, cmd, DMA_FROM_DEVICE, buffer, 313 len, NULL, 30 * HZ, 3, NULL); 314 if (result) 315 return -EIO; 316 317 /* Sanity check that we got the page back that we asked for */ 318 if (buffer[1] != page) 319 return -EIO; 320 321 return get_unaligned_be16(&buffer[2]) + 4; 322 } 323 324 /** 325 * scsi_get_vpd_page - Get Vital Product Data from a SCSI device 326 * @sdev: The device to ask 327 * @page: Which Vital Product Data to return 328 * @buf: where to store the VPD 329 * @buf_len: number of bytes in the VPD buffer area 330 * 331 * SCSI devices may optionally supply Vital Product Data. Each 'page' 332 * of VPD is defined in the appropriate SCSI document (eg SPC, SBC). 333 * If the device supports this VPD page, this routine returns a pointer 334 * to a buffer containing the data from that page. The caller is 335 * responsible for calling kfree() on this pointer when it is no longer 336 * needed. If we cannot retrieve the VPD page this routine returns %NULL. 337 */ 338 int scsi_get_vpd_page(struct scsi_device *sdev, u8 page, unsigned char *buf, 339 int buf_len) 340 { 341 int i, result; 342 343 if (sdev->skip_vpd_pages) 344 goto fail; 345 346 /* Ask for all the pages supported by this device */ 347 result = scsi_vpd_inquiry(sdev, buf, 0, buf_len); 348 if (result < 4) 349 goto fail; 350 351 /* If the user actually wanted this page, we can skip the rest */ 352 if (page == 0) 353 return 0; 354 355 for (i = 4; i < min(result, buf_len); i++) 356 if (buf[i] == page) 357 goto found; 358 359 if (i < result && i >= buf_len) 360 /* ran off the end of the buffer, give us benefit of doubt */ 361 goto found; 362 /* The device claims it doesn't support the requested page */ 363 goto fail; 364 365 found: 366 result = scsi_vpd_inquiry(sdev, buf, page, buf_len); 367 if (result < 0) 368 goto fail; 369 370 return 0; 371 372 fail: 373 return -EINVAL; 374 } 375 EXPORT_SYMBOL_GPL(scsi_get_vpd_page); 376 377 /** 378 * scsi_get_vpd_buf - Get Vital Product Data from a SCSI device 379 * @sdev: The device to ask 380 * @page: Which Vital Product Data to return 381 * 382 * Returns %NULL upon failure. 383 */ 384 static struct scsi_vpd *scsi_get_vpd_buf(struct scsi_device *sdev, u8 page) 385 { 386 struct scsi_vpd *vpd_buf; 387 int vpd_len = SCSI_VPD_PG_LEN, result; 388 389 retry_pg: 390 vpd_buf = kmalloc(sizeof(*vpd_buf) + vpd_len, GFP_KERNEL); 391 if (!vpd_buf) 392 return NULL; 393 394 result = scsi_vpd_inquiry(sdev, vpd_buf->data, page, vpd_len); 395 if (result < 0) { 396 kfree(vpd_buf); 397 return NULL; 398 } 399 if (result > vpd_len) { 400 vpd_len = result; 401 kfree(vpd_buf); 402 goto retry_pg; 403 } 404 405 vpd_buf->len = result; 406 407 return vpd_buf; 408 } 409 410 static void scsi_update_vpd_page(struct scsi_device *sdev, u8 page, 411 struct scsi_vpd __rcu **sdev_vpd_buf) 412 { 413 struct scsi_vpd *vpd_buf; 414 415 vpd_buf = scsi_get_vpd_buf(sdev, page); 416 if (!vpd_buf) 417 return; 418 419 mutex_lock(&sdev->inquiry_mutex); 420 vpd_buf = rcu_replace_pointer(*sdev_vpd_buf, vpd_buf, 421 lockdep_is_held(&sdev->inquiry_mutex)); 422 mutex_unlock(&sdev->inquiry_mutex); 423 424 if (vpd_buf) 425 kfree_rcu(vpd_buf, rcu); 426 } 427 428 /** 429 * scsi_attach_vpd - Attach Vital Product Data to a SCSI device structure 430 * @sdev: The device to ask 431 * 432 * Attach the 'Device Identification' VPD page (0x83) and the 433 * 'Unit Serial Number' VPD page (0x80) to a SCSI device 434 * structure. This information can be used to identify the device 435 * uniquely. 436 */ 437 void scsi_attach_vpd(struct scsi_device *sdev) 438 { 439 int i; 440 struct scsi_vpd *vpd_buf; 441 442 if (!scsi_device_supports_vpd(sdev)) 443 return; 444 445 /* Ask for all the pages supported by this device */ 446 vpd_buf = scsi_get_vpd_buf(sdev, 0); 447 if (!vpd_buf) 448 return; 449 450 for (i = 4; i < vpd_buf->len; i++) { 451 if (vpd_buf->data[i] == 0x0) 452 scsi_update_vpd_page(sdev, 0x0, &sdev->vpd_pg0); 453 if (vpd_buf->data[i] == 0x80) 454 scsi_update_vpd_page(sdev, 0x80, &sdev->vpd_pg80); 455 if (vpd_buf->data[i] == 0x83) 456 scsi_update_vpd_page(sdev, 0x83, &sdev->vpd_pg83); 457 if (vpd_buf->data[i] == 0x89) 458 scsi_update_vpd_page(sdev, 0x89, &sdev->vpd_pg89); 459 } 460 kfree(vpd_buf); 461 } 462 463 /** 464 * scsi_report_opcode - Find out if a given command opcode is supported 465 * @sdev: scsi device to query 466 * @buffer: scratch buffer (must be at least 20 bytes long) 467 * @len: length of buffer 468 * @opcode: opcode for command to look up 469 * 470 * Uses the REPORT SUPPORTED OPERATION CODES to look up the given 471 * opcode. Returns -EINVAL if RSOC fails, 0 if the command opcode is 472 * unsupported and 1 if the device claims to support the command. 473 */ 474 int scsi_report_opcode(struct scsi_device *sdev, unsigned char *buffer, 475 unsigned int len, unsigned char opcode) 476 { 477 unsigned char cmd[16]; 478 struct scsi_sense_hdr sshdr; 479 int result; 480 481 if (sdev->no_report_opcodes || sdev->scsi_level < SCSI_SPC_3) 482 return -EINVAL; 483 484 memset(cmd, 0, 16); 485 cmd[0] = MAINTENANCE_IN; 486 cmd[1] = MI_REPORT_SUPPORTED_OPERATION_CODES; 487 cmd[2] = 1; /* One command format */ 488 cmd[3] = opcode; 489 put_unaligned_be32(len, &cmd[6]); 490 memset(buffer, 0, len); 491 492 result = scsi_execute_req(sdev, cmd, DMA_FROM_DEVICE, buffer, len, 493 &sshdr, 30 * HZ, 3, NULL); 494 495 if (result < 0) 496 return result; 497 if (result && scsi_sense_valid(&sshdr) && 498 sshdr.sense_key == ILLEGAL_REQUEST && 499 (sshdr.asc == 0x20 || sshdr.asc == 0x24) && sshdr.ascq == 0x00) 500 return -EINVAL; 501 502 if ((buffer[1] & 3) == 3) /* Command supported */ 503 return 1; 504 505 return 0; 506 } 507 EXPORT_SYMBOL(scsi_report_opcode); 508 509 /** 510 * scsi_device_get - get an additional reference to a scsi_device 511 * @sdev: device to get a reference to 512 * 513 * Description: Gets a reference to the scsi_device and increments the use count 514 * of the underlying LLDD module. You must hold host_lock of the 515 * parent Scsi_Host or already have a reference when calling this. 516 * 517 * This will fail if a device is deleted or cancelled, or when the LLD module 518 * is in the process of being unloaded. 519 */ 520 int scsi_device_get(struct scsi_device *sdev) 521 { 522 if (sdev->sdev_state == SDEV_DEL || sdev->sdev_state == SDEV_CANCEL) 523 goto fail; 524 if (!get_device(&sdev->sdev_gendev)) 525 goto fail; 526 if (!try_module_get(sdev->host->hostt->module)) 527 goto fail_put_device; 528 return 0; 529 530 fail_put_device: 531 put_device(&sdev->sdev_gendev); 532 fail: 533 return -ENXIO; 534 } 535 EXPORT_SYMBOL(scsi_device_get); 536 537 /** 538 * scsi_device_put - release a reference to a scsi_device 539 * @sdev: device to release a reference on. 540 * 541 * Description: Release a reference to the scsi_device and decrements the use 542 * count of the underlying LLDD module. The device is freed once the last 543 * user vanishes. 544 */ 545 void scsi_device_put(struct scsi_device *sdev) 546 { 547 struct module *mod = sdev->host->hostt->module; 548 549 put_device(&sdev->sdev_gendev); 550 module_put(mod); 551 } 552 EXPORT_SYMBOL(scsi_device_put); 553 554 /* helper for shost_for_each_device, see that for documentation */ 555 struct scsi_device *__scsi_iterate_devices(struct Scsi_Host *shost, 556 struct scsi_device *prev) 557 { 558 struct list_head *list = (prev ? &prev->siblings : &shost->__devices); 559 struct scsi_device *next = NULL; 560 unsigned long flags; 561 562 spin_lock_irqsave(shost->host_lock, flags); 563 while (list->next != &shost->__devices) { 564 next = list_entry(list->next, struct scsi_device, siblings); 565 /* skip devices that we can't get a reference to */ 566 if (!scsi_device_get(next)) 567 break; 568 next = NULL; 569 list = list->next; 570 } 571 spin_unlock_irqrestore(shost->host_lock, flags); 572 573 if (prev) 574 scsi_device_put(prev); 575 return next; 576 } 577 EXPORT_SYMBOL(__scsi_iterate_devices); 578 579 /** 580 * starget_for_each_device - helper to walk all devices of a target 581 * @starget: target whose devices we want to iterate over. 582 * @data: Opaque passed to each function call. 583 * @fn: Function to call on each device 584 * 585 * This traverses over each device of @starget. The devices have 586 * a reference that must be released by scsi_host_put when breaking 587 * out of the loop. 588 */ 589 void starget_for_each_device(struct scsi_target *starget, void *data, 590 void (*fn)(struct scsi_device *, void *)) 591 { 592 struct Scsi_Host *shost = dev_to_shost(starget->dev.parent); 593 struct scsi_device *sdev; 594 595 shost_for_each_device(sdev, shost) { 596 if ((sdev->channel == starget->channel) && 597 (sdev->id == starget->id)) 598 fn(sdev, data); 599 } 600 } 601 EXPORT_SYMBOL(starget_for_each_device); 602 603 /** 604 * __starget_for_each_device - helper to walk all devices of a target (UNLOCKED) 605 * @starget: target whose devices we want to iterate over. 606 * @data: parameter for callback @fn() 607 * @fn: callback function that is invoked for each device 608 * 609 * This traverses over each device of @starget. It does _not_ 610 * take a reference on the scsi_device, so the whole loop must be 611 * protected by shost->host_lock. 612 * 613 * Note: The only reason why drivers would want to use this is because 614 * they need to access the device list in irq context. Otherwise you 615 * really want to use starget_for_each_device instead. 616 **/ 617 void __starget_for_each_device(struct scsi_target *starget, void *data, 618 void (*fn)(struct scsi_device *, void *)) 619 { 620 struct Scsi_Host *shost = dev_to_shost(starget->dev.parent); 621 struct scsi_device *sdev; 622 623 __shost_for_each_device(sdev, shost) { 624 if ((sdev->channel == starget->channel) && 625 (sdev->id == starget->id)) 626 fn(sdev, data); 627 } 628 } 629 EXPORT_SYMBOL(__starget_for_each_device); 630 631 /** 632 * __scsi_device_lookup_by_target - find a device given the target (UNLOCKED) 633 * @starget: SCSI target pointer 634 * @lun: SCSI Logical Unit Number 635 * 636 * Description: Looks up the scsi_device with the specified @lun for a given 637 * @starget. The returned scsi_device does not have an additional 638 * reference. You must hold the host's host_lock over this call and 639 * any access to the returned scsi_device. A scsi_device in state 640 * SDEV_DEL is skipped. 641 * 642 * Note: The only reason why drivers should use this is because 643 * they need to access the device list in irq context. Otherwise you 644 * really want to use scsi_device_lookup_by_target instead. 645 **/ 646 struct scsi_device *__scsi_device_lookup_by_target(struct scsi_target *starget, 647 u64 lun) 648 { 649 struct scsi_device *sdev; 650 651 list_for_each_entry(sdev, &starget->devices, same_target_siblings) { 652 if (sdev->sdev_state == SDEV_DEL) 653 continue; 654 if (sdev->lun ==lun) 655 return sdev; 656 } 657 658 return NULL; 659 } 660 EXPORT_SYMBOL(__scsi_device_lookup_by_target); 661 662 /** 663 * scsi_device_lookup_by_target - find a device given the target 664 * @starget: SCSI target pointer 665 * @lun: SCSI Logical Unit Number 666 * 667 * Description: Looks up the scsi_device with the specified @lun for a given 668 * @starget. The returned scsi_device has an additional reference that 669 * needs to be released with scsi_device_put once you're done with it. 670 **/ 671 struct scsi_device *scsi_device_lookup_by_target(struct scsi_target *starget, 672 u64 lun) 673 { 674 struct scsi_device *sdev; 675 struct Scsi_Host *shost = dev_to_shost(starget->dev.parent); 676 unsigned long flags; 677 678 spin_lock_irqsave(shost->host_lock, flags); 679 sdev = __scsi_device_lookup_by_target(starget, lun); 680 if (sdev && scsi_device_get(sdev)) 681 sdev = NULL; 682 spin_unlock_irqrestore(shost->host_lock, flags); 683 684 return sdev; 685 } 686 EXPORT_SYMBOL(scsi_device_lookup_by_target); 687 688 /** 689 * __scsi_device_lookup - find a device given the host (UNLOCKED) 690 * @shost: SCSI host pointer 691 * @channel: SCSI channel (zero if only one channel) 692 * @id: SCSI target number (physical unit number) 693 * @lun: SCSI Logical Unit Number 694 * 695 * Description: Looks up the scsi_device with the specified @channel, @id, @lun 696 * for a given host. The returned scsi_device does not have an additional 697 * reference. You must hold the host's host_lock over this call and any access 698 * to the returned scsi_device. 699 * 700 * Note: The only reason why drivers would want to use this is because 701 * they need to access the device list in irq context. Otherwise you 702 * really want to use scsi_device_lookup instead. 703 **/ 704 struct scsi_device *__scsi_device_lookup(struct Scsi_Host *shost, 705 uint channel, uint id, u64 lun) 706 { 707 struct scsi_device *sdev; 708 709 list_for_each_entry(sdev, &shost->__devices, siblings) { 710 if (sdev->sdev_state == SDEV_DEL) 711 continue; 712 if (sdev->channel == channel && sdev->id == id && 713 sdev->lun ==lun) 714 return sdev; 715 } 716 717 return NULL; 718 } 719 EXPORT_SYMBOL(__scsi_device_lookup); 720 721 /** 722 * scsi_device_lookup - find a device given the host 723 * @shost: SCSI host pointer 724 * @channel: SCSI channel (zero if only one channel) 725 * @id: SCSI target number (physical unit number) 726 * @lun: SCSI Logical Unit Number 727 * 728 * Description: Looks up the scsi_device with the specified @channel, @id, @lun 729 * for a given host. The returned scsi_device has an additional reference that 730 * needs to be released with scsi_device_put once you're done with it. 731 **/ 732 struct scsi_device *scsi_device_lookup(struct Scsi_Host *shost, 733 uint channel, uint id, u64 lun) 734 { 735 struct scsi_device *sdev; 736 unsigned long flags; 737 738 spin_lock_irqsave(shost->host_lock, flags); 739 sdev = __scsi_device_lookup(shost, channel, id, lun); 740 if (sdev && scsi_device_get(sdev)) 741 sdev = NULL; 742 spin_unlock_irqrestore(shost->host_lock, flags); 743 744 return sdev; 745 } 746 EXPORT_SYMBOL(scsi_device_lookup); 747 748 MODULE_DESCRIPTION("SCSI core"); 749 MODULE_LICENSE("GPL"); 750 751 module_param(scsi_logging_level, int, S_IRUGO|S_IWUSR); 752 MODULE_PARM_DESC(scsi_logging_level, "a bit mask of logging levels"); 753 754 static int __init init_scsi(void) 755 { 756 int error; 757 758 error = scsi_init_procfs(); 759 if (error) 760 goto cleanup_queue; 761 error = scsi_init_devinfo(); 762 if (error) 763 goto cleanup_procfs; 764 error = scsi_init_hosts(); 765 if (error) 766 goto cleanup_devlist; 767 error = scsi_init_sysctl(); 768 if (error) 769 goto cleanup_hosts; 770 error = scsi_sysfs_register(); 771 if (error) 772 goto cleanup_sysctl; 773 774 scsi_netlink_init(); 775 776 printk(KERN_NOTICE "SCSI subsystem initialized\n"); 777 return 0; 778 779 cleanup_sysctl: 780 scsi_exit_sysctl(); 781 cleanup_hosts: 782 scsi_exit_hosts(); 783 cleanup_devlist: 784 scsi_exit_devinfo(); 785 cleanup_procfs: 786 scsi_exit_procfs(); 787 cleanup_queue: 788 scsi_exit_queue(); 789 printk(KERN_ERR "SCSI subsystem failed to initialize, error = %d\n", 790 -error); 791 return error; 792 } 793 794 static void __exit exit_scsi(void) 795 { 796 scsi_netlink_exit(); 797 scsi_sysfs_unregister(); 798 scsi_exit_sysctl(); 799 scsi_exit_hosts(); 800 scsi_exit_devinfo(); 801 scsi_exit_procfs(); 802 scsi_exit_queue(); 803 } 804 805 subsys_initcall(init_scsi); 806 module_exit(exit_scsi); 807