1 /* 2 * bsg.c - block layer implementation of the sg v4 interface 3 * 4 * Copyright (C) 2004 Jens Axboe <axboe@suse.de> SUSE Labs 5 * Copyright (C) 2004 Peter M. Jones <pjones@redhat.com> 6 * 7 * This file is subject to the terms and conditions of the GNU General Public 8 * License version 2. See the file "COPYING" in the main directory of this 9 * archive for more details. 10 * 11 */ 12 #include <linux/module.h> 13 #include <linux/init.h> 14 #include <linux/file.h> 15 #include <linux/blkdev.h> 16 #include <linux/poll.h> 17 #include <linux/cdev.h> 18 #include <linux/jiffies.h> 19 #include <linux/percpu.h> 20 #include <linux/uio.h> 21 #include <linux/idr.h> 22 #include <linux/bsg.h> 23 #include <linux/slab.h> 24 25 #include <scsi/scsi.h> 26 #include <scsi/scsi_ioctl.h> 27 #include <scsi/scsi_cmnd.h> 28 #include <scsi/scsi_device.h> 29 #include <scsi/scsi_driver.h> 30 #include <scsi/sg.h> 31 32 #define BSG_DESCRIPTION "Block layer SCSI generic (bsg) driver" 33 #define BSG_VERSION "0.4" 34 35 struct bsg_device { 36 struct request_queue *queue; 37 spinlock_t lock; 38 struct list_head busy_list; 39 struct list_head done_list; 40 struct hlist_node dev_list; 41 atomic_t ref_count; 42 int queued_cmds; 43 int done_cmds; 44 wait_queue_head_t wq_done; 45 wait_queue_head_t wq_free; 46 char name[20]; 47 int max_queue; 48 unsigned long flags; 49 }; 50 51 enum { 52 BSG_F_BLOCK = 1, 53 }; 54 55 #define BSG_DEFAULT_CMDS 64 56 #define BSG_MAX_DEVS 32768 57 58 #undef BSG_DEBUG 59 60 #ifdef BSG_DEBUG 61 #define dprintk(fmt, args...) printk(KERN_ERR "%s: " fmt, __func__, ##args) 62 #else 63 #define dprintk(fmt, args...) 64 #endif 65 66 static DEFINE_MUTEX(bsg_mutex); 67 static DEFINE_IDR(bsg_minor_idr); 68 69 #define BSG_LIST_ARRAY_SIZE 8 70 static struct hlist_head bsg_device_list[BSG_LIST_ARRAY_SIZE]; 71 72 static struct class *bsg_class; 73 static int bsg_major; 74 75 static struct kmem_cache *bsg_cmd_cachep; 76 77 /* 78 * our internal command type 79 */ 80 struct bsg_command { 81 struct bsg_device *bd; 82 struct list_head list; 83 struct request *rq; 84 struct bio *bio; 85 struct bio *bidi_bio; 86 int err; 87 struct sg_io_v4 hdr; 88 }; 89 90 static void bsg_free_command(struct bsg_command *bc) 91 { 92 struct bsg_device *bd = bc->bd; 93 unsigned long flags; 94 95 kmem_cache_free(bsg_cmd_cachep, bc); 96 97 spin_lock_irqsave(&bd->lock, flags); 98 bd->queued_cmds--; 99 spin_unlock_irqrestore(&bd->lock, flags); 100 101 wake_up(&bd->wq_free); 102 } 103 104 static struct bsg_command *bsg_alloc_command(struct bsg_device *bd) 105 { 106 struct bsg_command *bc = ERR_PTR(-EINVAL); 107 108 spin_lock_irq(&bd->lock); 109 110 if (bd->queued_cmds >= bd->max_queue) 111 goto out; 112 113 bd->queued_cmds++; 114 spin_unlock_irq(&bd->lock); 115 116 bc = kmem_cache_zalloc(bsg_cmd_cachep, GFP_KERNEL); 117 if (unlikely(!bc)) { 118 spin_lock_irq(&bd->lock); 119 bd->queued_cmds--; 120 bc = ERR_PTR(-ENOMEM); 121 goto out; 122 } 123 124 bc->bd = bd; 125 INIT_LIST_HEAD(&bc->list); 126 dprintk("%s: returning free cmd %p\n", bd->name, bc); 127 return bc; 128 out: 129 spin_unlock_irq(&bd->lock); 130 return bc; 131 } 132 133 static inline struct hlist_head *bsg_dev_idx_hash(int index) 134 { 135 return &bsg_device_list[index & (BSG_LIST_ARRAY_SIZE - 1)]; 136 } 137 138 static int blk_fill_sgv4_hdr_rq(struct request_queue *q, struct request *rq, 139 struct sg_io_v4 *hdr, struct bsg_device *bd, 140 fmode_t has_write_perm) 141 { 142 struct scsi_request *req = scsi_req(rq); 143 144 if (hdr->request_len > BLK_MAX_CDB) { 145 req->cmd = kzalloc(hdr->request_len, GFP_KERNEL); 146 if (!req->cmd) 147 return -ENOMEM; 148 } 149 150 if (copy_from_user(req->cmd, (void __user *)(unsigned long)hdr->request, 151 hdr->request_len)) 152 return -EFAULT; 153 154 if (hdr->subprotocol == BSG_SUB_PROTOCOL_SCSI_CMD) { 155 if (blk_verify_command(req->cmd, has_write_perm)) 156 return -EPERM; 157 } else if (!capable(CAP_SYS_RAWIO)) 158 return -EPERM; 159 160 /* 161 * fill in request structure 162 */ 163 req->cmd_len = hdr->request_len; 164 165 rq->timeout = msecs_to_jiffies(hdr->timeout); 166 if (!rq->timeout) 167 rq->timeout = q->sg_timeout; 168 if (!rq->timeout) 169 rq->timeout = BLK_DEFAULT_SG_TIMEOUT; 170 if (rq->timeout < BLK_MIN_SG_TIMEOUT) 171 rq->timeout = BLK_MIN_SG_TIMEOUT; 172 173 return 0; 174 } 175 176 /* 177 * Check if sg_io_v4 from user is allowed and valid 178 */ 179 static int 180 bsg_validate_sgv4_hdr(struct sg_io_v4 *hdr, int *op) 181 { 182 int ret = 0; 183 184 if (hdr->guard != 'Q') 185 return -EINVAL; 186 187 switch (hdr->protocol) { 188 case BSG_PROTOCOL_SCSI: 189 switch (hdr->subprotocol) { 190 case BSG_SUB_PROTOCOL_SCSI_CMD: 191 case BSG_SUB_PROTOCOL_SCSI_TRANSPORT: 192 break; 193 default: 194 ret = -EINVAL; 195 } 196 break; 197 default: 198 ret = -EINVAL; 199 } 200 201 *op = hdr->dout_xfer_len ? REQ_OP_SCSI_OUT : REQ_OP_SCSI_IN; 202 return ret; 203 } 204 205 /* 206 * map sg_io_v4 to a request. 207 */ 208 static struct request * 209 bsg_map_hdr(struct bsg_device *bd, struct sg_io_v4 *hdr, fmode_t has_write_perm) 210 { 211 struct request_queue *q = bd->queue; 212 struct request *rq, *next_rq = NULL; 213 int ret; 214 unsigned int op, dxfer_len; 215 void __user *dxferp = NULL; 216 struct bsg_class_device *bcd = &q->bsg_dev; 217 218 /* if the LLD has been removed then the bsg_unregister_queue will 219 * eventually be called and the class_dev was freed, so we can no 220 * longer use this request_queue. Return no such address. 221 */ 222 if (!bcd->class_dev) 223 return ERR_PTR(-ENXIO); 224 225 dprintk("map hdr %llx/%u %llx/%u\n", (unsigned long long) hdr->dout_xferp, 226 hdr->dout_xfer_len, (unsigned long long) hdr->din_xferp, 227 hdr->din_xfer_len); 228 229 ret = bsg_validate_sgv4_hdr(hdr, &op); 230 if (ret) 231 return ERR_PTR(ret); 232 233 /* 234 * map scatter-gather elements separately and string them to request 235 */ 236 rq = blk_get_request(q, op, GFP_KERNEL); 237 if (IS_ERR(rq)) 238 return rq; 239 240 ret = blk_fill_sgv4_hdr_rq(q, rq, hdr, bd, has_write_perm); 241 if (ret) 242 goto out; 243 244 if (op == REQ_OP_SCSI_OUT && hdr->din_xfer_len) { 245 if (!test_bit(QUEUE_FLAG_BIDI, &q->queue_flags)) { 246 ret = -EOPNOTSUPP; 247 goto out; 248 } 249 250 next_rq = blk_get_request(q, REQ_OP_SCSI_IN, GFP_KERNEL); 251 if (IS_ERR(next_rq)) { 252 ret = PTR_ERR(next_rq); 253 next_rq = NULL; 254 goto out; 255 } 256 rq->next_rq = next_rq; 257 258 dxferp = (void __user *)(unsigned long)hdr->din_xferp; 259 ret = blk_rq_map_user(q, next_rq, NULL, dxferp, 260 hdr->din_xfer_len, GFP_KERNEL); 261 if (ret) 262 goto out; 263 } 264 265 if (hdr->dout_xfer_len) { 266 dxfer_len = hdr->dout_xfer_len; 267 dxferp = (void __user *)(unsigned long)hdr->dout_xferp; 268 } else if (hdr->din_xfer_len) { 269 dxfer_len = hdr->din_xfer_len; 270 dxferp = (void __user *)(unsigned long)hdr->din_xferp; 271 } else 272 dxfer_len = 0; 273 274 if (dxfer_len) { 275 ret = blk_rq_map_user(q, rq, NULL, dxferp, dxfer_len, 276 GFP_KERNEL); 277 if (ret) 278 goto out; 279 } 280 281 return rq; 282 out: 283 scsi_req_free_cmd(scsi_req(rq)); 284 blk_put_request(rq); 285 if (next_rq) { 286 blk_rq_unmap_user(next_rq->bio); 287 blk_put_request(next_rq); 288 } 289 return ERR_PTR(ret); 290 } 291 292 /* 293 * async completion call-back from the block layer, when scsi/ide/whatever 294 * calls end_that_request_last() on a request 295 */ 296 static void bsg_rq_end_io(struct request *rq, blk_status_t status) 297 { 298 struct bsg_command *bc = rq->end_io_data; 299 struct bsg_device *bd = bc->bd; 300 unsigned long flags; 301 302 dprintk("%s: finished rq %p bc %p, bio %p\n", 303 bd->name, rq, bc, bc->bio); 304 305 bc->hdr.duration = jiffies_to_msecs(jiffies - bc->hdr.duration); 306 307 spin_lock_irqsave(&bd->lock, flags); 308 list_move_tail(&bc->list, &bd->done_list); 309 bd->done_cmds++; 310 spin_unlock_irqrestore(&bd->lock, flags); 311 312 wake_up(&bd->wq_done); 313 } 314 315 /* 316 * do final setup of a 'bc' and submit the matching 'rq' to the block 317 * layer for io 318 */ 319 static void bsg_add_command(struct bsg_device *bd, struct request_queue *q, 320 struct bsg_command *bc, struct request *rq) 321 { 322 int at_head = (0 == (bc->hdr.flags & BSG_FLAG_Q_AT_TAIL)); 323 324 /* 325 * add bc command to busy queue and submit rq for io 326 */ 327 bc->rq = rq; 328 bc->bio = rq->bio; 329 if (rq->next_rq) 330 bc->bidi_bio = rq->next_rq->bio; 331 bc->hdr.duration = jiffies; 332 spin_lock_irq(&bd->lock); 333 list_add_tail(&bc->list, &bd->busy_list); 334 spin_unlock_irq(&bd->lock); 335 336 dprintk("%s: queueing rq %p, bc %p\n", bd->name, rq, bc); 337 338 rq->end_io_data = bc; 339 blk_execute_rq_nowait(q, NULL, rq, at_head, bsg_rq_end_io); 340 } 341 342 static struct bsg_command *bsg_next_done_cmd(struct bsg_device *bd) 343 { 344 struct bsg_command *bc = NULL; 345 346 spin_lock_irq(&bd->lock); 347 if (bd->done_cmds) { 348 bc = list_first_entry(&bd->done_list, struct bsg_command, list); 349 list_del(&bc->list); 350 bd->done_cmds--; 351 } 352 spin_unlock_irq(&bd->lock); 353 354 return bc; 355 } 356 357 /* 358 * Get a finished command from the done list 359 */ 360 static struct bsg_command *bsg_get_done_cmd(struct bsg_device *bd) 361 { 362 struct bsg_command *bc; 363 int ret; 364 365 do { 366 bc = bsg_next_done_cmd(bd); 367 if (bc) 368 break; 369 370 if (!test_bit(BSG_F_BLOCK, &bd->flags)) { 371 bc = ERR_PTR(-EAGAIN); 372 break; 373 } 374 375 ret = wait_event_interruptible(bd->wq_done, bd->done_cmds); 376 if (ret) { 377 bc = ERR_PTR(-ERESTARTSYS); 378 break; 379 } 380 } while (1); 381 382 dprintk("%s: returning done %p\n", bd->name, bc); 383 384 return bc; 385 } 386 387 static int blk_complete_sgv4_hdr_rq(struct request *rq, struct sg_io_v4 *hdr, 388 struct bio *bio, struct bio *bidi_bio) 389 { 390 struct scsi_request *req = scsi_req(rq); 391 int ret = 0; 392 393 dprintk("rq %p bio %p 0x%x\n", rq, bio, req->result); 394 /* 395 * fill in all the output members 396 */ 397 hdr->device_status = req->result & 0xff; 398 hdr->transport_status = host_byte(req->result); 399 hdr->driver_status = driver_byte(req->result); 400 hdr->info = 0; 401 if (hdr->device_status || hdr->transport_status || hdr->driver_status) 402 hdr->info |= SG_INFO_CHECK; 403 hdr->response_len = 0; 404 405 if (req->sense_len && hdr->response) { 406 int len = min_t(unsigned int, hdr->max_response_len, 407 req->sense_len); 408 409 ret = copy_to_user((void __user *)(unsigned long)hdr->response, 410 req->sense, len); 411 if (!ret) 412 hdr->response_len = len; 413 else 414 ret = -EFAULT; 415 } 416 417 if (rq->next_rq) { 418 hdr->dout_resid = req->resid_len; 419 hdr->din_resid = scsi_req(rq->next_rq)->resid_len; 420 blk_rq_unmap_user(bidi_bio); 421 blk_put_request(rq->next_rq); 422 } else if (rq_data_dir(rq) == READ) 423 hdr->din_resid = req->resid_len; 424 else 425 hdr->dout_resid = req->resid_len; 426 427 /* 428 * If the request generated a negative error number, return it 429 * (providing we aren't already returning an error); if it's 430 * just a protocol response (i.e. non negative), that gets 431 * processed above. 432 */ 433 if (!ret && req->result < 0) 434 ret = req->result; 435 436 blk_rq_unmap_user(bio); 437 scsi_req_free_cmd(req); 438 blk_put_request(rq); 439 440 return ret; 441 } 442 443 static bool bsg_complete(struct bsg_device *bd) 444 { 445 bool ret = false; 446 bool spin; 447 448 do { 449 spin_lock_irq(&bd->lock); 450 451 BUG_ON(bd->done_cmds > bd->queued_cmds); 452 453 /* 454 * All commands consumed. 455 */ 456 if (bd->done_cmds == bd->queued_cmds) 457 ret = true; 458 459 spin = !test_bit(BSG_F_BLOCK, &bd->flags); 460 461 spin_unlock_irq(&bd->lock); 462 } while (!ret && spin); 463 464 return ret; 465 } 466 467 static int bsg_complete_all_commands(struct bsg_device *bd) 468 { 469 struct bsg_command *bc; 470 int ret, tret; 471 472 dprintk("%s: entered\n", bd->name); 473 474 /* 475 * wait for all commands to complete 476 */ 477 io_wait_event(bd->wq_done, bsg_complete(bd)); 478 479 /* 480 * discard done commands 481 */ 482 ret = 0; 483 do { 484 spin_lock_irq(&bd->lock); 485 if (!bd->queued_cmds) { 486 spin_unlock_irq(&bd->lock); 487 break; 488 } 489 spin_unlock_irq(&bd->lock); 490 491 bc = bsg_get_done_cmd(bd); 492 if (IS_ERR(bc)) 493 break; 494 495 tret = blk_complete_sgv4_hdr_rq(bc->rq, &bc->hdr, bc->bio, 496 bc->bidi_bio); 497 if (!ret) 498 ret = tret; 499 500 bsg_free_command(bc); 501 } while (1); 502 503 return ret; 504 } 505 506 static int 507 __bsg_read(char __user *buf, size_t count, struct bsg_device *bd, 508 const struct iovec *iov, ssize_t *bytes_read) 509 { 510 struct bsg_command *bc; 511 int nr_commands, ret; 512 513 if (count % sizeof(struct sg_io_v4)) 514 return -EINVAL; 515 516 ret = 0; 517 nr_commands = count / sizeof(struct sg_io_v4); 518 while (nr_commands) { 519 bc = bsg_get_done_cmd(bd); 520 if (IS_ERR(bc)) { 521 ret = PTR_ERR(bc); 522 break; 523 } 524 525 /* 526 * this is the only case where we need to copy data back 527 * after completing the request. so do that here, 528 * bsg_complete_work() cannot do that for us 529 */ 530 ret = blk_complete_sgv4_hdr_rq(bc->rq, &bc->hdr, bc->bio, 531 bc->bidi_bio); 532 533 if (copy_to_user(buf, &bc->hdr, sizeof(bc->hdr))) 534 ret = -EFAULT; 535 536 bsg_free_command(bc); 537 538 if (ret) 539 break; 540 541 buf += sizeof(struct sg_io_v4); 542 *bytes_read += sizeof(struct sg_io_v4); 543 nr_commands--; 544 } 545 546 return ret; 547 } 548 549 static inline void bsg_set_block(struct bsg_device *bd, struct file *file) 550 { 551 if (file->f_flags & O_NONBLOCK) 552 clear_bit(BSG_F_BLOCK, &bd->flags); 553 else 554 set_bit(BSG_F_BLOCK, &bd->flags); 555 } 556 557 /* 558 * Check if the error is a "real" error that we should return. 559 */ 560 static inline int err_block_err(int ret) 561 { 562 if (ret && ret != -ENOSPC && ret != -ENODATA && ret != -EAGAIN) 563 return 1; 564 565 return 0; 566 } 567 568 static ssize_t 569 bsg_read(struct file *file, char __user *buf, size_t count, loff_t *ppos) 570 { 571 struct bsg_device *bd = file->private_data; 572 int ret; 573 ssize_t bytes_read; 574 575 dprintk("%s: read %zd bytes\n", bd->name, count); 576 577 bsg_set_block(bd, file); 578 579 bytes_read = 0; 580 ret = __bsg_read(buf, count, bd, NULL, &bytes_read); 581 *ppos = bytes_read; 582 583 if (!bytes_read || err_block_err(ret)) 584 bytes_read = ret; 585 586 return bytes_read; 587 } 588 589 static int __bsg_write(struct bsg_device *bd, const char __user *buf, 590 size_t count, ssize_t *bytes_written, 591 fmode_t has_write_perm) 592 { 593 struct bsg_command *bc; 594 struct request *rq; 595 int ret, nr_commands; 596 597 if (count % sizeof(struct sg_io_v4)) 598 return -EINVAL; 599 600 nr_commands = count / sizeof(struct sg_io_v4); 601 rq = NULL; 602 bc = NULL; 603 ret = 0; 604 while (nr_commands) { 605 struct request_queue *q = bd->queue; 606 607 bc = bsg_alloc_command(bd); 608 if (IS_ERR(bc)) { 609 ret = PTR_ERR(bc); 610 bc = NULL; 611 break; 612 } 613 614 if (copy_from_user(&bc->hdr, buf, sizeof(bc->hdr))) { 615 ret = -EFAULT; 616 break; 617 } 618 619 /* 620 * get a request, fill in the blanks, and add to request queue 621 */ 622 rq = bsg_map_hdr(bd, &bc->hdr, has_write_perm); 623 if (IS_ERR(rq)) { 624 ret = PTR_ERR(rq); 625 rq = NULL; 626 break; 627 } 628 629 bsg_add_command(bd, q, bc, rq); 630 bc = NULL; 631 rq = NULL; 632 nr_commands--; 633 buf += sizeof(struct sg_io_v4); 634 *bytes_written += sizeof(struct sg_io_v4); 635 } 636 637 if (bc) 638 bsg_free_command(bc); 639 640 return ret; 641 } 642 643 static ssize_t 644 bsg_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos) 645 { 646 struct bsg_device *bd = file->private_data; 647 ssize_t bytes_written; 648 int ret; 649 650 dprintk("%s: write %zd bytes\n", bd->name, count); 651 652 if (unlikely(uaccess_kernel())) 653 return -EINVAL; 654 655 bsg_set_block(bd, file); 656 657 bytes_written = 0; 658 ret = __bsg_write(bd, buf, count, &bytes_written, 659 file->f_mode & FMODE_WRITE); 660 661 *ppos = bytes_written; 662 663 /* 664 * return bytes written on non-fatal errors 665 */ 666 if (!bytes_written || err_block_err(ret)) 667 bytes_written = ret; 668 669 dprintk("%s: returning %zd\n", bd->name, bytes_written); 670 return bytes_written; 671 } 672 673 static struct bsg_device *bsg_alloc_device(void) 674 { 675 struct bsg_device *bd; 676 677 bd = kzalloc(sizeof(struct bsg_device), GFP_KERNEL); 678 if (unlikely(!bd)) 679 return NULL; 680 681 spin_lock_init(&bd->lock); 682 683 bd->max_queue = BSG_DEFAULT_CMDS; 684 685 INIT_LIST_HEAD(&bd->busy_list); 686 INIT_LIST_HEAD(&bd->done_list); 687 INIT_HLIST_NODE(&bd->dev_list); 688 689 init_waitqueue_head(&bd->wq_free); 690 init_waitqueue_head(&bd->wq_done); 691 return bd; 692 } 693 694 static void bsg_kref_release_function(struct kref *kref) 695 { 696 struct bsg_class_device *bcd = 697 container_of(kref, struct bsg_class_device, ref); 698 struct device *parent = bcd->parent; 699 700 if (bcd->release) 701 bcd->release(bcd->parent); 702 703 put_device(parent); 704 } 705 706 static int bsg_put_device(struct bsg_device *bd) 707 { 708 int ret = 0, do_free; 709 struct request_queue *q = bd->queue; 710 711 mutex_lock(&bsg_mutex); 712 713 do_free = atomic_dec_and_test(&bd->ref_count); 714 if (!do_free) { 715 mutex_unlock(&bsg_mutex); 716 goto out; 717 } 718 719 hlist_del(&bd->dev_list); 720 mutex_unlock(&bsg_mutex); 721 722 dprintk("%s: tearing down\n", bd->name); 723 724 /* 725 * close can always block 726 */ 727 set_bit(BSG_F_BLOCK, &bd->flags); 728 729 /* 730 * correct error detection baddies here again. it's the responsibility 731 * of the app to properly reap commands before close() if it wants 732 * fool-proof error detection 733 */ 734 ret = bsg_complete_all_commands(bd); 735 736 kfree(bd); 737 out: 738 kref_put(&q->bsg_dev.ref, bsg_kref_release_function); 739 if (do_free) 740 blk_put_queue(q); 741 return ret; 742 } 743 744 static struct bsg_device *bsg_add_device(struct inode *inode, 745 struct request_queue *rq, 746 struct file *file) 747 { 748 struct bsg_device *bd; 749 #ifdef BSG_DEBUG 750 unsigned char buf[32]; 751 #endif 752 753 if (!blk_queue_scsi_passthrough(rq)) { 754 WARN_ONCE(true, "Attempt to register a non-SCSI queue\n"); 755 return ERR_PTR(-EINVAL); 756 } 757 758 if (!blk_get_queue(rq)) 759 return ERR_PTR(-ENXIO); 760 761 bd = bsg_alloc_device(); 762 if (!bd) { 763 blk_put_queue(rq); 764 return ERR_PTR(-ENOMEM); 765 } 766 767 bd->queue = rq; 768 769 bsg_set_block(bd, file); 770 771 atomic_set(&bd->ref_count, 1); 772 mutex_lock(&bsg_mutex); 773 hlist_add_head(&bd->dev_list, bsg_dev_idx_hash(iminor(inode))); 774 775 strncpy(bd->name, dev_name(rq->bsg_dev.class_dev), sizeof(bd->name) - 1); 776 dprintk("bound to <%s>, max queue %d\n", 777 format_dev_t(buf, inode->i_rdev), bd->max_queue); 778 779 mutex_unlock(&bsg_mutex); 780 return bd; 781 } 782 783 static struct bsg_device *__bsg_get_device(int minor, struct request_queue *q) 784 { 785 struct bsg_device *bd; 786 787 mutex_lock(&bsg_mutex); 788 789 hlist_for_each_entry(bd, bsg_dev_idx_hash(minor), dev_list) { 790 if (bd->queue == q) { 791 atomic_inc(&bd->ref_count); 792 goto found; 793 } 794 } 795 bd = NULL; 796 found: 797 mutex_unlock(&bsg_mutex); 798 return bd; 799 } 800 801 static struct bsg_device *bsg_get_device(struct inode *inode, struct file *file) 802 { 803 struct bsg_device *bd; 804 struct bsg_class_device *bcd; 805 806 /* 807 * find the class device 808 */ 809 mutex_lock(&bsg_mutex); 810 bcd = idr_find(&bsg_minor_idr, iminor(inode)); 811 if (bcd) 812 kref_get(&bcd->ref); 813 mutex_unlock(&bsg_mutex); 814 815 if (!bcd) 816 return ERR_PTR(-ENODEV); 817 818 bd = __bsg_get_device(iminor(inode), bcd->queue); 819 if (bd) 820 return bd; 821 822 bd = bsg_add_device(inode, bcd->queue, file); 823 if (IS_ERR(bd)) 824 kref_put(&bcd->ref, bsg_kref_release_function); 825 826 return bd; 827 } 828 829 static int bsg_open(struct inode *inode, struct file *file) 830 { 831 struct bsg_device *bd; 832 833 bd = bsg_get_device(inode, file); 834 835 if (IS_ERR(bd)) 836 return PTR_ERR(bd); 837 838 file->private_data = bd; 839 return 0; 840 } 841 842 static int bsg_release(struct inode *inode, struct file *file) 843 { 844 struct bsg_device *bd = file->private_data; 845 846 file->private_data = NULL; 847 return bsg_put_device(bd); 848 } 849 850 static unsigned int bsg_poll(struct file *file, poll_table *wait) 851 { 852 struct bsg_device *bd = file->private_data; 853 unsigned int mask = 0; 854 855 poll_wait(file, &bd->wq_done, wait); 856 poll_wait(file, &bd->wq_free, wait); 857 858 spin_lock_irq(&bd->lock); 859 if (!list_empty(&bd->done_list)) 860 mask |= POLLIN | POLLRDNORM; 861 if (bd->queued_cmds < bd->max_queue) 862 mask |= POLLOUT; 863 spin_unlock_irq(&bd->lock); 864 865 return mask; 866 } 867 868 static long bsg_ioctl(struct file *file, unsigned int cmd, unsigned long arg) 869 { 870 struct bsg_device *bd = file->private_data; 871 int __user *uarg = (int __user *) arg; 872 int ret; 873 874 switch (cmd) { 875 /* 876 * our own ioctls 877 */ 878 case SG_GET_COMMAND_Q: 879 return put_user(bd->max_queue, uarg); 880 case SG_SET_COMMAND_Q: { 881 int queue; 882 883 if (get_user(queue, uarg)) 884 return -EFAULT; 885 if (queue < 1) 886 return -EINVAL; 887 888 spin_lock_irq(&bd->lock); 889 bd->max_queue = queue; 890 spin_unlock_irq(&bd->lock); 891 return 0; 892 } 893 894 /* 895 * SCSI/sg ioctls 896 */ 897 case SG_GET_VERSION_NUM: 898 case SCSI_IOCTL_GET_IDLUN: 899 case SCSI_IOCTL_GET_BUS_NUMBER: 900 case SG_SET_TIMEOUT: 901 case SG_GET_TIMEOUT: 902 case SG_GET_RESERVED_SIZE: 903 case SG_SET_RESERVED_SIZE: 904 case SG_EMULATED_HOST: 905 case SCSI_IOCTL_SEND_COMMAND: { 906 void __user *uarg = (void __user *) arg; 907 return scsi_cmd_ioctl(bd->queue, NULL, file->f_mode, cmd, uarg); 908 } 909 case SG_IO: { 910 struct request *rq; 911 struct bio *bio, *bidi_bio = NULL; 912 struct sg_io_v4 hdr; 913 int at_head; 914 915 if (copy_from_user(&hdr, uarg, sizeof(hdr))) 916 return -EFAULT; 917 918 rq = bsg_map_hdr(bd, &hdr, file->f_mode & FMODE_WRITE); 919 if (IS_ERR(rq)) 920 return PTR_ERR(rq); 921 922 bio = rq->bio; 923 if (rq->next_rq) 924 bidi_bio = rq->next_rq->bio; 925 926 at_head = (0 == (hdr.flags & BSG_FLAG_Q_AT_TAIL)); 927 blk_execute_rq(bd->queue, NULL, rq, at_head); 928 ret = blk_complete_sgv4_hdr_rq(rq, &hdr, bio, bidi_bio); 929 930 if (copy_to_user(uarg, &hdr, sizeof(hdr))) 931 return -EFAULT; 932 933 return ret; 934 } 935 default: 936 return -ENOTTY; 937 } 938 } 939 940 static const struct file_operations bsg_fops = { 941 .read = bsg_read, 942 .write = bsg_write, 943 .poll = bsg_poll, 944 .open = bsg_open, 945 .release = bsg_release, 946 .unlocked_ioctl = bsg_ioctl, 947 .owner = THIS_MODULE, 948 .llseek = default_llseek, 949 }; 950 951 void bsg_unregister_queue(struct request_queue *q) 952 { 953 struct bsg_class_device *bcd = &q->bsg_dev; 954 955 if (!bcd->class_dev) 956 return; 957 958 mutex_lock(&bsg_mutex); 959 idr_remove(&bsg_minor_idr, bcd->minor); 960 if (q->kobj.sd) 961 sysfs_remove_link(&q->kobj, "bsg"); 962 device_unregister(bcd->class_dev); 963 bcd->class_dev = NULL; 964 kref_put(&bcd->ref, bsg_kref_release_function); 965 mutex_unlock(&bsg_mutex); 966 } 967 EXPORT_SYMBOL_GPL(bsg_unregister_queue); 968 969 int bsg_register_queue(struct request_queue *q, struct device *parent, 970 const char *name, void (*release)(struct device *)) 971 { 972 struct bsg_class_device *bcd; 973 dev_t dev; 974 int ret; 975 struct device *class_dev = NULL; 976 const char *devname; 977 978 if (name) 979 devname = name; 980 else 981 devname = dev_name(parent); 982 983 /* 984 * we need a proper transport to send commands, not a stacked device 985 */ 986 if (!queue_is_rq_based(q)) 987 return 0; 988 989 bcd = &q->bsg_dev; 990 memset(bcd, 0, sizeof(*bcd)); 991 992 mutex_lock(&bsg_mutex); 993 994 ret = idr_alloc(&bsg_minor_idr, bcd, 0, BSG_MAX_DEVS, GFP_KERNEL); 995 if (ret < 0) { 996 if (ret == -ENOSPC) { 997 printk(KERN_ERR "bsg: too many bsg devices\n"); 998 ret = -EINVAL; 999 } 1000 goto unlock; 1001 } 1002 1003 bcd->minor = ret; 1004 bcd->queue = q; 1005 bcd->parent = get_device(parent); 1006 bcd->release = release; 1007 kref_init(&bcd->ref); 1008 dev = MKDEV(bsg_major, bcd->minor); 1009 class_dev = device_create(bsg_class, parent, dev, NULL, "%s", devname); 1010 if (IS_ERR(class_dev)) { 1011 ret = PTR_ERR(class_dev); 1012 goto put_dev; 1013 } 1014 bcd->class_dev = class_dev; 1015 1016 if (q->kobj.sd) { 1017 ret = sysfs_create_link(&q->kobj, &bcd->class_dev->kobj, "bsg"); 1018 if (ret) 1019 goto unregister_class_dev; 1020 } 1021 1022 mutex_unlock(&bsg_mutex); 1023 return 0; 1024 1025 unregister_class_dev: 1026 device_unregister(class_dev); 1027 put_dev: 1028 put_device(parent); 1029 idr_remove(&bsg_minor_idr, bcd->minor); 1030 unlock: 1031 mutex_unlock(&bsg_mutex); 1032 return ret; 1033 } 1034 EXPORT_SYMBOL_GPL(bsg_register_queue); 1035 1036 static struct cdev bsg_cdev; 1037 1038 static char *bsg_devnode(struct device *dev, umode_t *mode) 1039 { 1040 return kasprintf(GFP_KERNEL, "bsg/%s", dev_name(dev)); 1041 } 1042 1043 static int __init bsg_init(void) 1044 { 1045 int ret, i; 1046 dev_t devid; 1047 1048 bsg_cmd_cachep = kmem_cache_create("bsg_cmd", 1049 sizeof(struct bsg_command), 0, 0, NULL); 1050 if (!bsg_cmd_cachep) { 1051 printk(KERN_ERR "bsg: failed creating slab cache\n"); 1052 return -ENOMEM; 1053 } 1054 1055 for (i = 0; i < BSG_LIST_ARRAY_SIZE; i++) 1056 INIT_HLIST_HEAD(&bsg_device_list[i]); 1057 1058 bsg_class = class_create(THIS_MODULE, "bsg"); 1059 if (IS_ERR(bsg_class)) { 1060 ret = PTR_ERR(bsg_class); 1061 goto destroy_kmemcache; 1062 } 1063 bsg_class->devnode = bsg_devnode; 1064 1065 ret = alloc_chrdev_region(&devid, 0, BSG_MAX_DEVS, "bsg"); 1066 if (ret) 1067 goto destroy_bsg_class; 1068 1069 bsg_major = MAJOR(devid); 1070 1071 cdev_init(&bsg_cdev, &bsg_fops); 1072 ret = cdev_add(&bsg_cdev, MKDEV(bsg_major, 0), BSG_MAX_DEVS); 1073 if (ret) 1074 goto unregister_chrdev; 1075 1076 printk(KERN_INFO BSG_DESCRIPTION " version " BSG_VERSION 1077 " loaded (major %d)\n", bsg_major); 1078 return 0; 1079 unregister_chrdev: 1080 unregister_chrdev_region(MKDEV(bsg_major, 0), BSG_MAX_DEVS); 1081 destroy_bsg_class: 1082 class_destroy(bsg_class); 1083 destroy_kmemcache: 1084 kmem_cache_destroy(bsg_cmd_cachep); 1085 return ret; 1086 } 1087 1088 MODULE_AUTHOR("Jens Axboe"); 1089 MODULE_DESCRIPTION(BSG_DESCRIPTION); 1090 MODULE_LICENSE("GPL"); 1091 1092 device_initcall(bsg_init); 1093