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 scsi_req_init(rq); 240 241 ret = blk_fill_sgv4_hdr_rq(q, rq, hdr, bd, has_write_perm); 242 if (ret) 243 goto out; 244 245 if (op == REQ_OP_SCSI_OUT && hdr->din_xfer_len) { 246 if (!test_bit(QUEUE_FLAG_BIDI, &q->queue_flags)) { 247 ret = -EOPNOTSUPP; 248 goto out; 249 } 250 251 next_rq = blk_get_request(q, REQ_OP_SCSI_IN, GFP_KERNEL); 252 if (IS_ERR(next_rq)) { 253 ret = PTR_ERR(next_rq); 254 next_rq = NULL; 255 goto out; 256 } 257 rq->next_rq = next_rq; 258 259 dxferp = (void __user *)(unsigned long)hdr->din_xferp; 260 ret = blk_rq_map_user(q, next_rq, NULL, dxferp, 261 hdr->din_xfer_len, GFP_KERNEL); 262 if (ret) 263 goto out; 264 } 265 266 if (hdr->dout_xfer_len) { 267 dxfer_len = hdr->dout_xfer_len; 268 dxferp = (void __user *)(unsigned long)hdr->dout_xferp; 269 } else if (hdr->din_xfer_len) { 270 dxfer_len = hdr->din_xfer_len; 271 dxferp = (void __user *)(unsigned long)hdr->din_xferp; 272 } else 273 dxfer_len = 0; 274 275 if (dxfer_len) { 276 ret = blk_rq_map_user(q, rq, NULL, dxferp, dxfer_len, 277 GFP_KERNEL); 278 if (ret) 279 goto out; 280 } 281 282 return rq; 283 out: 284 scsi_req_free_cmd(scsi_req(rq)); 285 blk_put_request(rq); 286 if (next_rq) { 287 blk_rq_unmap_user(next_rq->bio); 288 blk_put_request(next_rq); 289 } 290 return ERR_PTR(ret); 291 } 292 293 /* 294 * async completion call-back from the block layer, when scsi/ide/whatever 295 * calls end_that_request_last() on a request 296 */ 297 static void bsg_rq_end_io(struct request *rq, int uptodate) 298 { 299 struct bsg_command *bc = rq->end_io_data; 300 struct bsg_device *bd = bc->bd; 301 unsigned long flags; 302 303 dprintk("%s: finished rq %p bc %p, bio %p stat %d\n", 304 bd->name, rq, bc, bc->bio, uptodate); 305 306 bc->hdr.duration = jiffies_to_msecs(jiffies - bc->hdr.duration); 307 308 spin_lock_irqsave(&bd->lock, flags); 309 list_move_tail(&bc->list, &bd->done_list); 310 bd->done_cmds++; 311 spin_unlock_irqrestore(&bd->lock, flags); 312 313 wake_up(&bd->wq_done); 314 } 315 316 /* 317 * do final setup of a 'bc' and submit the matching 'rq' to the block 318 * layer for io 319 */ 320 static void bsg_add_command(struct bsg_device *bd, struct request_queue *q, 321 struct bsg_command *bc, struct request *rq) 322 { 323 int at_head = (0 == (bc->hdr.flags & BSG_FLAG_Q_AT_TAIL)); 324 325 /* 326 * add bc command to busy queue and submit rq for io 327 */ 328 bc->rq = rq; 329 bc->bio = rq->bio; 330 if (rq->next_rq) 331 bc->bidi_bio = rq->next_rq->bio; 332 bc->hdr.duration = jiffies; 333 spin_lock_irq(&bd->lock); 334 list_add_tail(&bc->list, &bd->busy_list); 335 spin_unlock_irq(&bd->lock); 336 337 dprintk("%s: queueing rq %p, bc %p\n", bd->name, rq, bc); 338 339 rq->end_io_data = bc; 340 blk_execute_rq_nowait(q, NULL, rq, at_head, bsg_rq_end_io); 341 } 342 343 static struct bsg_command *bsg_next_done_cmd(struct bsg_device *bd) 344 { 345 struct bsg_command *bc = NULL; 346 347 spin_lock_irq(&bd->lock); 348 if (bd->done_cmds) { 349 bc = list_first_entry(&bd->done_list, struct bsg_command, list); 350 list_del(&bc->list); 351 bd->done_cmds--; 352 } 353 spin_unlock_irq(&bd->lock); 354 355 return bc; 356 } 357 358 /* 359 * Get a finished command from the done list 360 */ 361 static struct bsg_command *bsg_get_done_cmd(struct bsg_device *bd) 362 { 363 struct bsg_command *bc; 364 int ret; 365 366 do { 367 bc = bsg_next_done_cmd(bd); 368 if (bc) 369 break; 370 371 if (!test_bit(BSG_F_BLOCK, &bd->flags)) { 372 bc = ERR_PTR(-EAGAIN); 373 break; 374 } 375 376 ret = wait_event_interruptible(bd->wq_done, bd->done_cmds); 377 if (ret) { 378 bc = ERR_PTR(-ERESTARTSYS); 379 break; 380 } 381 } while (1); 382 383 dprintk("%s: returning done %p\n", bd->name, bc); 384 385 return bc; 386 } 387 388 static int blk_complete_sgv4_hdr_rq(struct request *rq, struct sg_io_v4 *hdr, 389 struct bio *bio, struct bio *bidi_bio) 390 { 391 struct scsi_request *req = scsi_req(rq); 392 int ret = 0; 393 394 dprintk("rq %p bio %p 0x%x\n", rq, bio, rq->errors); 395 /* 396 * fill in all the output members 397 */ 398 hdr->device_status = rq->errors & 0xff; 399 hdr->transport_status = host_byte(rq->errors); 400 hdr->driver_status = driver_byte(rq->errors); 401 hdr->info = 0; 402 if (hdr->device_status || hdr->transport_status || hdr->driver_status) 403 hdr->info |= SG_INFO_CHECK; 404 hdr->response_len = 0; 405 406 if (req->sense_len && hdr->response) { 407 int len = min_t(unsigned int, hdr->max_response_len, 408 req->sense_len); 409 410 ret = copy_to_user((void __user *)(unsigned long)hdr->response, 411 req->sense, len); 412 if (!ret) 413 hdr->response_len = len; 414 else 415 ret = -EFAULT; 416 } 417 418 if (rq->next_rq) { 419 hdr->dout_resid = req->resid_len; 420 hdr->din_resid = scsi_req(rq->next_rq)->resid_len; 421 blk_rq_unmap_user(bidi_bio); 422 blk_put_request(rq->next_rq); 423 } else if (rq_data_dir(rq) == READ) 424 hdr->din_resid = req->resid_len; 425 else 426 hdr->dout_resid = req->resid_len; 427 428 /* 429 * If the request generated a negative error number, return it 430 * (providing we aren't already returning an error); if it's 431 * just a protocol response (i.e. non negative), that gets 432 * processed above. 433 */ 434 if (!ret && rq->errors < 0) 435 ret = rq->errors; 436 437 blk_rq_unmap_user(bio); 438 scsi_req_free_cmd(req); 439 blk_put_request(rq); 440 441 return ret; 442 } 443 444 static bool bsg_complete(struct bsg_device *bd) 445 { 446 bool ret = false; 447 bool spin; 448 449 do { 450 spin_lock_irq(&bd->lock); 451 452 BUG_ON(bd->done_cmds > bd->queued_cmds); 453 454 /* 455 * All commands consumed. 456 */ 457 if (bd->done_cmds == bd->queued_cmds) 458 ret = true; 459 460 spin = !test_bit(BSG_F_BLOCK, &bd->flags); 461 462 spin_unlock_irq(&bd->lock); 463 } while (!ret && spin); 464 465 return ret; 466 } 467 468 static int bsg_complete_all_commands(struct bsg_device *bd) 469 { 470 struct bsg_command *bc; 471 int ret, tret; 472 473 dprintk("%s: entered\n", bd->name); 474 475 /* 476 * wait for all commands to complete 477 */ 478 io_wait_event(bd->wq_done, bsg_complete(bd)); 479 480 /* 481 * discard done commands 482 */ 483 ret = 0; 484 do { 485 spin_lock_irq(&bd->lock); 486 if (!bd->queued_cmds) { 487 spin_unlock_irq(&bd->lock); 488 break; 489 } 490 spin_unlock_irq(&bd->lock); 491 492 bc = bsg_get_done_cmd(bd); 493 if (IS_ERR(bc)) 494 break; 495 496 tret = blk_complete_sgv4_hdr_rq(bc->rq, &bc->hdr, bc->bio, 497 bc->bidi_bio); 498 if (!ret) 499 ret = tret; 500 501 bsg_free_command(bc); 502 } while (1); 503 504 return ret; 505 } 506 507 static int 508 __bsg_read(char __user *buf, size_t count, struct bsg_device *bd, 509 const struct iovec *iov, ssize_t *bytes_read) 510 { 511 struct bsg_command *bc; 512 int nr_commands, ret; 513 514 if (count % sizeof(struct sg_io_v4)) 515 return -EINVAL; 516 517 ret = 0; 518 nr_commands = count / sizeof(struct sg_io_v4); 519 while (nr_commands) { 520 bc = bsg_get_done_cmd(bd); 521 if (IS_ERR(bc)) { 522 ret = PTR_ERR(bc); 523 break; 524 } 525 526 /* 527 * this is the only case where we need to copy data back 528 * after completing the request. so do that here, 529 * bsg_complete_work() cannot do that for us 530 */ 531 ret = blk_complete_sgv4_hdr_rq(bc->rq, &bc->hdr, bc->bio, 532 bc->bidi_bio); 533 534 if (copy_to_user(buf, &bc->hdr, sizeof(bc->hdr))) 535 ret = -EFAULT; 536 537 bsg_free_command(bc); 538 539 if (ret) 540 break; 541 542 buf += sizeof(struct sg_io_v4); 543 *bytes_read += sizeof(struct sg_io_v4); 544 nr_commands--; 545 } 546 547 return ret; 548 } 549 550 static inline void bsg_set_block(struct bsg_device *bd, struct file *file) 551 { 552 if (file->f_flags & O_NONBLOCK) 553 clear_bit(BSG_F_BLOCK, &bd->flags); 554 else 555 set_bit(BSG_F_BLOCK, &bd->flags); 556 } 557 558 /* 559 * Check if the error is a "real" error that we should return. 560 */ 561 static inline int err_block_err(int ret) 562 { 563 if (ret && ret != -ENOSPC && ret != -ENODATA && ret != -EAGAIN) 564 return 1; 565 566 return 0; 567 } 568 569 static ssize_t 570 bsg_read(struct file *file, char __user *buf, size_t count, loff_t *ppos) 571 { 572 struct bsg_device *bd = file->private_data; 573 int ret; 574 ssize_t bytes_read; 575 576 dprintk("%s: read %zd bytes\n", bd->name, count); 577 578 bsg_set_block(bd, file); 579 580 bytes_read = 0; 581 ret = __bsg_read(buf, count, bd, NULL, &bytes_read); 582 *ppos = bytes_read; 583 584 if (!bytes_read || err_block_err(ret)) 585 bytes_read = ret; 586 587 return bytes_read; 588 } 589 590 static int __bsg_write(struct bsg_device *bd, const char __user *buf, 591 size_t count, ssize_t *bytes_written, 592 fmode_t has_write_perm) 593 { 594 struct bsg_command *bc; 595 struct request *rq; 596 int ret, nr_commands; 597 598 if (count % sizeof(struct sg_io_v4)) 599 return -EINVAL; 600 601 nr_commands = count / sizeof(struct sg_io_v4); 602 rq = NULL; 603 bc = NULL; 604 ret = 0; 605 while (nr_commands) { 606 struct request_queue *q = bd->queue; 607 608 bc = bsg_alloc_command(bd); 609 if (IS_ERR(bc)) { 610 ret = PTR_ERR(bc); 611 bc = NULL; 612 break; 613 } 614 615 if (copy_from_user(&bc->hdr, buf, sizeof(bc->hdr))) { 616 ret = -EFAULT; 617 break; 618 } 619 620 /* 621 * get a request, fill in the blanks, and add to request queue 622 */ 623 rq = bsg_map_hdr(bd, &bc->hdr, has_write_perm); 624 if (IS_ERR(rq)) { 625 ret = PTR_ERR(rq); 626 rq = NULL; 627 break; 628 } 629 630 bsg_add_command(bd, q, bc, rq); 631 bc = NULL; 632 rq = NULL; 633 nr_commands--; 634 buf += sizeof(struct sg_io_v4); 635 *bytes_written += sizeof(struct sg_io_v4); 636 } 637 638 if (bc) 639 bsg_free_command(bc); 640 641 return ret; 642 } 643 644 static ssize_t 645 bsg_write(struct file *file, const char __user *buf, size_t count, loff_t *ppos) 646 { 647 struct bsg_device *bd = file->private_data; 648 ssize_t bytes_written; 649 int ret; 650 651 dprintk("%s: write %zd bytes\n", bd->name, count); 652 653 if (unlikely(segment_eq(get_fs(), KERNEL_DS))) 654 return -EINVAL; 655 656 bsg_set_block(bd, file); 657 658 bytes_written = 0; 659 ret = __bsg_write(bd, buf, count, &bytes_written, 660 file->f_mode & FMODE_WRITE); 661 662 *ppos = bytes_written; 663 664 /* 665 * return bytes written on non-fatal errors 666 */ 667 if (!bytes_written || err_block_err(ret)) 668 bytes_written = ret; 669 670 dprintk("%s: returning %zd\n", bd->name, bytes_written); 671 return bytes_written; 672 } 673 674 static struct bsg_device *bsg_alloc_device(void) 675 { 676 struct bsg_device *bd; 677 678 bd = kzalloc(sizeof(struct bsg_device), GFP_KERNEL); 679 if (unlikely(!bd)) 680 return NULL; 681 682 spin_lock_init(&bd->lock); 683 684 bd->max_queue = BSG_DEFAULT_CMDS; 685 686 INIT_LIST_HEAD(&bd->busy_list); 687 INIT_LIST_HEAD(&bd->done_list); 688 INIT_HLIST_NODE(&bd->dev_list); 689 690 init_waitqueue_head(&bd->wq_free); 691 init_waitqueue_head(&bd->wq_done); 692 return bd; 693 } 694 695 static void bsg_kref_release_function(struct kref *kref) 696 { 697 struct bsg_class_device *bcd = 698 container_of(kref, struct bsg_class_device, ref); 699 struct device *parent = bcd->parent; 700 701 if (bcd->release) 702 bcd->release(bcd->parent); 703 704 put_device(parent); 705 } 706 707 static int bsg_put_device(struct bsg_device *bd) 708 { 709 int ret = 0, do_free; 710 struct request_queue *q = bd->queue; 711 712 mutex_lock(&bsg_mutex); 713 714 do_free = atomic_dec_and_test(&bd->ref_count); 715 if (!do_free) { 716 mutex_unlock(&bsg_mutex); 717 goto out; 718 } 719 720 hlist_del(&bd->dev_list); 721 mutex_unlock(&bsg_mutex); 722 723 dprintk("%s: tearing down\n", bd->name); 724 725 /* 726 * close can always block 727 */ 728 set_bit(BSG_F_BLOCK, &bd->flags); 729 730 /* 731 * correct error detection baddies here again. it's the responsibility 732 * of the app to properly reap commands before close() if it wants 733 * fool-proof error detection 734 */ 735 ret = bsg_complete_all_commands(bd); 736 737 kfree(bd); 738 out: 739 kref_put(&q->bsg_dev.ref, bsg_kref_release_function); 740 if (do_free) 741 blk_put_queue(q); 742 return ret; 743 } 744 745 static struct bsg_device *bsg_add_device(struct inode *inode, 746 struct request_queue *rq, 747 struct file *file) 748 { 749 struct bsg_device *bd; 750 #ifdef BSG_DEBUG 751 unsigned char buf[32]; 752 #endif 753 if (!blk_get_queue(rq)) 754 return ERR_PTR(-ENXIO); 755 756 bd = bsg_alloc_device(); 757 if (!bd) { 758 blk_put_queue(rq); 759 return ERR_PTR(-ENOMEM); 760 } 761 762 bd->queue = rq; 763 764 bsg_set_block(bd, file); 765 766 atomic_set(&bd->ref_count, 1); 767 mutex_lock(&bsg_mutex); 768 hlist_add_head(&bd->dev_list, bsg_dev_idx_hash(iminor(inode))); 769 770 strncpy(bd->name, dev_name(rq->bsg_dev.class_dev), sizeof(bd->name) - 1); 771 dprintk("bound to <%s>, max queue %d\n", 772 format_dev_t(buf, inode->i_rdev), bd->max_queue); 773 774 mutex_unlock(&bsg_mutex); 775 return bd; 776 } 777 778 static struct bsg_device *__bsg_get_device(int minor, struct request_queue *q) 779 { 780 struct bsg_device *bd; 781 782 mutex_lock(&bsg_mutex); 783 784 hlist_for_each_entry(bd, bsg_dev_idx_hash(minor), dev_list) { 785 if (bd->queue == q) { 786 atomic_inc(&bd->ref_count); 787 goto found; 788 } 789 } 790 bd = NULL; 791 found: 792 mutex_unlock(&bsg_mutex); 793 return bd; 794 } 795 796 static struct bsg_device *bsg_get_device(struct inode *inode, struct file *file) 797 { 798 struct bsg_device *bd; 799 struct bsg_class_device *bcd; 800 801 /* 802 * find the class device 803 */ 804 mutex_lock(&bsg_mutex); 805 bcd = idr_find(&bsg_minor_idr, iminor(inode)); 806 if (bcd) 807 kref_get(&bcd->ref); 808 mutex_unlock(&bsg_mutex); 809 810 if (!bcd) 811 return ERR_PTR(-ENODEV); 812 813 bd = __bsg_get_device(iminor(inode), bcd->queue); 814 if (bd) 815 return bd; 816 817 bd = bsg_add_device(inode, bcd->queue, file); 818 if (IS_ERR(bd)) 819 kref_put(&bcd->ref, bsg_kref_release_function); 820 821 return bd; 822 } 823 824 static int bsg_open(struct inode *inode, struct file *file) 825 { 826 struct bsg_device *bd; 827 828 bd = bsg_get_device(inode, file); 829 830 if (IS_ERR(bd)) 831 return PTR_ERR(bd); 832 833 file->private_data = bd; 834 return 0; 835 } 836 837 static int bsg_release(struct inode *inode, struct file *file) 838 { 839 struct bsg_device *bd = file->private_data; 840 841 file->private_data = NULL; 842 return bsg_put_device(bd); 843 } 844 845 static unsigned int bsg_poll(struct file *file, poll_table *wait) 846 { 847 struct bsg_device *bd = file->private_data; 848 unsigned int mask = 0; 849 850 poll_wait(file, &bd->wq_done, wait); 851 poll_wait(file, &bd->wq_free, wait); 852 853 spin_lock_irq(&bd->lock); 854 if (!list_empty(&bd->done_list)) 855 mask |= POLLIN | POLLRDNORM; 856 if (bd->queued_cmds < bd->max_queue) 857 mask |= POLLOUT; 858 spin_unlock_irq(&bd->lock); 859 860 return mask; 861 } 862 863 static long bsg_ioctl(struct file *file, unsigned int cmd, unsigned long arg) 864 { 865 struct bsg_device *bd = file->private_data; 866 int __user *uarg = (int __user *) arg; 867 int ret; 868 869 switch (cmd) { 870 /* 871 * our own ioctls 872 */ 873 case SG_GET_COMMAND_Q: 874 return put_user(bd->max_queue, uarg); 875 case SG_SET_COMMAND_Q: { 876 int queue; 877 878 if (get_user(queue, uarg)) 879 return -EFAULT; 880 if (queue < 1) 881 return -EINVAL; 882 883 spin_lock_irq(&bd->lock); 884 bd->max_queue = queue; 885 spin_unlock_irq(&bd->lock); 886 return 0; 887 } 888 889 /* 890 * SCSI/sg ioctls 891 */ 892 case SG_GET_VERSION_NUM: 893 case SCSI_IOCTL_GET_IDLUN: 894 case SCSI_IOCTL_GET_BUS_NUMBER: 895 case SG_SET_TIMEOUT: 896 case SG_GET_TIMEOUT: 897 case SG_GET_RESERVED_SIZE: 898 case SG_SET_RESERVED_SIZE: 899 case SG_EMULATED_HOST: 900 case SCSI_IOCTL_SEND_COMMAND: { 901 void __user *uarg = (void __user *) arg; 902 return scsi_cmd_ioctl(bd->queue, NULL, file->f_mode, cmd, uarg); 903 } 904 case SG_IO: { 905 struct request *rq; 906 struct bio *bio, *bidi_bio = NULL; 907 struct sg_io_v4 hdr; 908 int at_head; 909 910 if (copy_from_user(&hdr, uarg, sizeof(hdr))) 911 return -EFAULT; 912 913 rq = bsg_map_hdr(bd, &hdr, file->f_mode & FMODE_WRITE); 914 if (IS_ERR(rq)) 915 return PTR_ERR(rq); 916 917 bio = rq->bio; 918 if (rq->next_rq) 919 bidi_bio = rq->next_rq->bio; 920 921 at_head = (0 == (hdr.flags & BSG_FLAG_Q_AT_TAIL)); 922 blk_execute_rq(bd->queue, NULL, rq, at_head); 923 ret = blk_complete_sgv4_hdr_rq(rq, &hdr, bio, bidi_bio); 924 925 if (copy_to_user(uarg, &hdr, sizeof(hdr))) 926 return -EFAULT; 927 928 return ret; 929 } 930 /* 931 * block device ioctls 932 */ 933 default: 934 #if 0 935 return ioctl_by_bdev(bd->bdev, cmd, arg); 936 #else 937 return -ENOTTY; 938 #endif 939 } 940 } 941 942 static const struct file_operations bsg_fops = { 943 .read = bsg_read, 944 .write = bsg_write, 945 .poll = bsg_poll, 946 .open = bsg_open, 947 .release = bsg_release, 948 .unlocked_ioctl = bsg_ioctl, 949 .owner = THIS_MODULE, 950 .llseek = default_llseek, 951 }; 952 953 void bsg_unregister_queue(struct request_queue *q) 954 { 955 struct bsg_class_device *bcd = &q->bsg_dev; 956 957 if (!bcd->class_dev) 958 return; 959 960 mutex_lock(&bsg_mutex); 961 idr_remove(&bsg_minor_idr, bcd->minor); 962 if (q->kobj.sd) 963 sysfs_remove_link(&q->kobj, "bsg"); 964 device_unregister(bcd->class_dev); 965 bcd->class_dev = NULL; 966 kref_put(&bcd->ref, bsg_kref_release_function); 967 mutex_unlock(&bsg_mutex); 968 } 969 EXPORT_SYMBOL_GPL(bsg_unregister_queue); 970 971 int bsg_register_queue(struct request_queue *q, struct device *parent, 972 const char *name, void (*release)(struct device *)) 973 { 974 struct bsg_class_device *bcd; 975 dev_t dev; 976 int ret; 977 struct device *class_dev = NULL; 978 const char *devname; 979 980 if (name) 981 devname = name; 982 else 983 devname = dev_name(parent); 984 985 /* 986 * we need a proper transport to send commands, not a stacked device 987 */ 988 if (!queue_is_rq_based(q)) 989 return 0; 990 991 bcd = &q->bsg_dev; 992 memset(bcd, 0, sizeof(*bcd)); 993 994 mutex_lock(&bsg_mutex); 995 996 ret = idr_alloc(&bsg_minor_idr, bcd, 0, BSG_MAX_DEVS, GFP_KERNEL); 997 if (ret < 0) { 998 if (ret == -ENOSPC) { 999 printk(KERN_ERR "bsg: too many bsg devices\n"); 1000 ret = -EINVAL; 1001 } 1002 goto unlock; 1003 } 1004 1005 bcd->minor = ret; 1006 bcd->queue = q; 1007 bcd->parent = get_device(parent); 1008 bcd->release = release; 1009 kref_init(&bcd->ref); 1010 dev = MKDEV(bsg_major, bcd->minor); 1011 class_dev = device_create(bsg_class, parent, dev, NULL, "%s", devname); 1012 if (IS_ERR(class_dev)) { 1013 ret = PTR_ERR(class_dev); 1014 goto put_dev; 1015 } 1016 bcd->class_dev = class_dev; 1017 1018 if (q->kobj.sd) { 1019 ret = sysfs_create_link(&q->kobj, &bcd->class_dev->kobj, "bsg"); 1020 if (ret) 1021 goto unregister_class_dev; 1022 } 1023 1024 mutex_unlock(&bsg_mutex); 1025 return 0; 1026 1027 unregister_class_dev: 1028 device_unregister(class_dev); 1029 put_dev: 1030 put_device(parent); 1031 idr_remove(&bsg_minor_idr, bcd->minor); 1032 unlock: 1033 mutex_unlock(&bsg_mutex); 1034 return ret; 1035 } 1036 EXPORT_SYMBOL_GPL(bsg_register_queue); 1037 1038 static struct cdev bsg_cdev; 1039 1040 static char *bsg_devnode(struct device *dev, umode_t *mode) 1041 { 1042 return kasprintf(GFP_KERNEL, "bsg/%s", dev_name(dev)); 1043 } 1044 1045 static int __init bsg_init(void) 1046 { 1047 int ret, i; 1048 dev_t devid; 1049 1050 bsg_cmd_cachep = kmem_cache_create("bsg_cmd", 1051 sizeof(struct bsg_command), 0, 0, NULL); 1052 if (!bsg_cmd_cachep) { 1053 printk(KERN_ERR "bsg: failed creating slab cache\n"); 1054 return -ENOMEM; 1055 } 1056 1057 for (i = 0; i < BSG_LIST_ARRAY_SIZE; i++) 1058 INIT_HLIST_HEAD(&bsg_device_list[i]); 1059 1060 bsg_class = class_create(THIS_MODULE, "bsg"); 1061 if (IS_ERR(bsg_class)) { 1062 ret = PTR_ERR(bsg_class); 1063 goto destroy_kmemcache; 1064 } 1065 bsg_class->devnode = bsg_devnode; 1066 1067 ret = alloc_chrdev_region(&devid, 0, BSG_MAX_DEVS, "bsg"); 1068 if (ret) 1069 goto destroy_bsg_class; 1070 1071 bsg_major = MAJOR(devid); 1072 1073 cdev_init(&bsg_cdev, &bsg_fops); 1074 ret = cdev_add(&bsg_cdev, MKDEV(bsg_major, 0), BSG_MAX_DEVS); 1075 if (ret) 1076 goto unregister_chrdev; 1077 1078 printk(KERN_INFO BSG_DESCRIPTION " version " BSG_VERSION 1079 " loaded (major %d)\n", bsg_major); 1080 return 0; 1081 unregister_chrdev: 1082 unregister_chrdev_region(MKDEV(bsg_major, 0), BSG_MAX_DEVS); 1083 destroy_bsg_class: 1084 class_destroy(bsg_class); 1085 destroy_kmemcache: 1086 kmem_cache_destroy(bsg_cmd_cachep); 1087 return ret; 1088 } 1089 1090 MODULE_AUTHOR("Jens Axboe"); 1091 MODULE_DESCRIPTION(BSG_DESCRIPTION); 1092 MODULE_LICENSE("GPL"); 1093 1094 device_initcall(bsg_init); 1095