1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * Userspace block device - block device which IO is handled from userspace 4 * 5 * Take full use of io_uring passthrough command for communicating with 6 * ublk userspace daemon(ublksrvd) for handling basic IO request. 7 * 8 * Copyright 2022 Ming Lei <ming.lei@redhat.com> 9 * 10 * (part of code stolen from loop.c) 11 */ 12 #include <linux/module.h> 13 #include <linux/moduleparam.h> 14 #include <linux/sched.h> 15 #include <linux/fs.h> 16 #include <linux/pagemap.h> 17 #include <linux/file.h> 18 #include <linux/stat.h> 19 #include <linux/errno.h> 20 #include <linux/major.h> 21 #include <linux/wait.h> 22 #include <linux/blkdev.h> 23 #include <linux/init.h> 24 #include <linux/swap.h> 25 #include <linux/slab.h> 26 #include <linux/compat.h> 27 #include <linux/mutex.h> 28 #include <linux/writeback.h> 29 #include <linux/completion.h> 30 #include <linux/highmem.h> 31 #include <linux/sysfs.h> 32 #include <linux/miscdevice.h> 33 #include <linux/falloc.h> 34 #include <linux/uio.h> 35 #include <linux/ioprio.h> 36 #include <linux/sched/mm.h> 37 #include <linux/uaccess.h> 38 #include <linux/cdev.h> 39 #include <linux/io_uring.h> 40 #include <linux/blk-mq.h> 41 #include <linux/delay.h> 42 #include <linux/mm.h> 43 #include <asm/page.h> 44 #include <linux/task_work.h> 45 #include <uapi/linux/ublk_cmd.h> 46 47 #define UBLK_MINORS (1U << MINORBITS) 48 49 /* All UBLK_F_* have to be included into UBLK_F_ALL */ 50 #define UBLK_F_ALL (UBLK_F_SUPPORT_ZERO_COPY \ 51 | UBLK_F_URING_CMD_COMP_IN_TASK \ 52 | UBLK_F_NEED_GET_DATA \ 53 | UBLK_F_USER_RECOVERY \ 54 | UBLK_F_USER_RECOVERY_REISSUE) 55 56 /* All UBLK_PARAM_TYPE_* should be included here */ 57 #define UBLK_PARAM_TYPE_ALL (UBLK_PARAM_TYPE_BASIC | UBLK_PARAM_TYPE_DISCARD) 58 59 struct ublk_rq_data { 60 struct callback_head work; 61 }; 62 63 struct ublk_uring_cmd_pdu { 64 struct request *req; 65 }; 66 67 /* 68 * io command is active: sqe cmd is received, and its cqe isn't done 69 * 70 * If the flag is set, the io command is owned by ublk driver, and waited 71 * for incoming blk-mq request from the ublk block device. 72 * 73 * If the flag is cleared, the io command will be completed, and owned by 74 * ublk server. 75 */ 76 #define UBLK_IO_FLAG_ACTIVE 0x01 77 78 /* 79 * IO command is completed via cqe, and it is being handled by ublksrv, and 80 * not committed yet 81 * 82 * Basically exclusively with UBLK_IO_FLAG_ACTIVE, so can be served for 83 * cross verification 84 */ 85 #define UBLK_IO_FLAG_OWNED_BY_SRV 0x02 86 87 /* 88 * IO command is aborted, so this flag is set in case of 89 * !UBLK_IO_FLAG_ACTIVE. 90 * 91 * After this flag is observed, any pending or new incoming request 92 * associated with this io command will be failed immediately 93 */ 94 #define UBLK_IO_FLAG_ABORTED 0x04 95 96 /* 97 * UBLK_IO_FLAG_NEED_GET_DATA is set because IO command requires 98 * get data buffer address from ublksrv. 99 * 100 * Then, bio data could be copied into this data buffer for a WRITE request 101 * after the IO command is issued again and UBLK_IO_FLAG_NEED_GET_DATA is unset. 102 */ 103 #define UBLK_IO_FLAG_NEED_GET_DATA 0x08 104 105 struct ublk_io { 106 /* userspace buffer address from io cmd */ 107 __u64 addr; 108 unsigned int flags; 109 int res; 110 111 struct io_uring_cmd *cmd; 112 }; 113 114 struct ublk_queue { 115 int q_id; 116 int q_depth; 117 118 unsigned long flags; 119 struct task_struct *ubq_daemon; 120 char *io_cmd_buf; 121 122 unsigned long io_addr; /* mapped vm address */ 123 unsigned int max_io_sz; 124 bool force_abort; 125 unsigned short nr_io_ready; /* how many ios setup */ 126 struct ublk_device *dev; 127 struct ublk_io ios[]; 128 }; 129 130 #define UBLK_DAEMON_MONITOR_PERIOD (5 * HZ) 131 132 struct ublk_device { 133 struct gendisk *ub_disk; 134 135 char *__queues; 136 137 unsigned short queue_size; 138 struct ublksrv_ctrl_dev_info dev_info; 139 140 struct blk_mq_tag_set tag_set; 141 142 struct cdev cdev; 143 struct device cdev_dev; 144 145 #define UB_STATE_OPEN 0 146 #define UB_STATE_USED 1 147 unsigned long state; 148 int ub_number; 149 150 struct mutex mutex; 151 152 spinlock_t mm_lock; 153 struct mm_struct *mm; 154 155 struct ublk_params params; 156 157 struct completion completion; 158 unsigned int nr_queues_ready; 159 atomic_t nr_aborted_queues; 160 161 /* 162 * Our ubq->daemon may be killed without any notification, so 163 * monitor each queue's daemon periodically 164 */ 165 struct delayed_work monitor_work; 166 struct work_struct quiesce_work; 167 struct work_struct stop_work; 168 }; 169 170 /* header of ublk_params */ 171 struct ublk_params_header { 172 __u32 len; 173 __u32 types; 174 }; 175 176 static dev_t ublk_chr_devt; 177 static struct class *ublk_chr_class; 178 179 static DEFINE_IDR(ublk_index_idr); 180 static DEFINE_SPINLOCK(ublk_idr_lock); 181 static wait_queue_head_t ublk_idr_wq; /* wait until one idr is freed */ 182 183 static DEFINE_MUTEX(ublk_ctl_mutex); 184 185 static struct miscdevice ublk_misc; 186 187 static void ublk_dev_param_basic_apply(struct ublk_device *ub) 188 { 189 struct request_queue *q = ub->ub_disk->queue; 190 const struct ublk_param_basic *p = &ub->params.basic; 191 192 blk_queue_logical_block_size(q, 1 << p->logical_bs_shift); 193 blk_queue_physical_block_size(q, 1 << p->physical_bs_shift); 194 blk_queue_io_min(q, 1 << p->io_min_shift); 195 blk_queue_io_opt(q, 1 << p->io_opt_shift); 196 197 blk_queue_write_cache(q, p->attrs & UBLK_ATTR_VOLATILE_CACHE, 198 p->attrs & UBLK_ATTR_FUA); 199 if (p->attrs & UBLK_ATTR_ROTATIONAL) 200 blk_queue_flag_clear(QUEUE_FLAG_NONROT, q); 201 else 202 blk_queue_flag_set(QUEUE_FLAG_NONROT, q); 203 204 blk_queue_max_hw_sectors(q, p->max_sectors); 205 blk_queue_chunk_sectors(q, p->chunk_sectors); 206 blk_queue_virt_boundary(q, p->virt_boundary_mask); 207 208 if (p->attrs & UBLK_ATTR_READ_ONLY) 209 set_disk_ro(ub->ub_disk, true); 210 211 set_capacity(ub->ub_disk, p->dev_sectors); 212 } 213 214 static void ublk_dev_param_discard_apply(struct ublk_device *ub) 215 { 216 struct request_queue *q = ub->ub_disk->queue; 217 const struct ublk_param_discard *p = &ub->params.discard; 218 219 q->limits.discard_alignment = p->discard_alignment; 220 q->limits.discard_granularity = p->discard_granularity; 221 blk_queue_max_discard_sectors(q, p->max_discard_sectors); 222 blk_queue_max_write_zeroes_sectors(q, 223 p->max_write_zeroes_sectors); 224 blk_queue_max_discard_segments(q, p->max_discard_segments); 225 } 226 227 static int ublk_validate_params(const struct ublk_device *ub) 228 { 229 /* basic param is the only one which must be set */ 230 if (ub->params.types & UBLK_PARAM_TYPE_BASIC) { 231 const struct ublk_param_basic *p = &ub->params.basic; 232 233 if (p->logical_bs_shift > PAGE_SHIFT) 234 return -EINVAL; 235 236 if (p->logical_bs_shift > p->physical_bs_shift) 237 return -EINVAL; 238 239 if (p->max_sectors > (ub->dev_info.max_io_buf_bytes >> 9)) 240 return -EINVAL; 241 } else 242 return -EINVAL; 243 244 if (ub->params.types & UBLK_PARAM_TYPE_DISCARD) { 245 const struct ublk_param_discard *p = &ub->params.discard; 246 247 /* So far, only support single segment discard */ 248 if (p->max_discard_sectors && p->max_discard_segments != 1) 249 return -EINVAL; 250 251 if (!p->discard_granularity) 252 return -EINVAL; 253 } 254 255 return 0; 256 } 257 258 static int ublk_apply_params(struct ublk_device *ub) 259 { 260 if (!(ub->params.types & UBLK_PARAM_TYPE_BASIC)) 261 return -EINVAL; 262 263 ublk_dev_param_basic_apply(ub); 264 265 if (ub->params.types & UBLK_PARAM_TYPE_DISCARD) 266 ublk_dev_param_discard_apply(ub); 267 268 return 0; 269 } 270 271 static inline bool ublk_can_use_task_work(const struct ublk_queue *ubq) 272 { 273 if (IS_BUILTIN(CONFIG_BLK_DEV_UBLK) && 274 !(ubq->flags & UBLK_F_URING_CMD_COMP_IN_TASK)) 275 return true; 276 return false; 277 } 278 279 static inline bool ublk_need_get_data(const struct ublk_queue *ubq) 280 { 281 if (ubq->flags & UBLK_F_NEED_GET_DATA) 282 return true; 283 return false; 284 } 285 286 static struct ublk_device *ublk_get_device(struct ublk_device *ub) 287 { 288 if (kobject_get_unless_zero(&ub->cdev_dev.kobj)) 289 return ub; 290 return NULL; 291 } 292 293 static void ublk_put_device(struct ublk_device *ub) 294 { 295 put_device(&ub->cdev_dev); 296 } 297 298 static inline struct ublk_queue *ublk_get_queue(struct ublk_device *dev, 299 int qid) 300 { 301 return (struct ublk_queue *)&(dev->__queues[qid * dev->queue_size]); 302 } 303 304 static inline bool ublk_rq_has_data(const struct request *rq) 305 { 306 return rq->bio && bio_has_data(rq->bio); 307 } 308 309 static inline struct ublksrv_io_desc *ublk_get_iod(struct ublk_queue *ubq, 310 int tag) 311 { 312 return (struct ublksrv_io_desc *) 313 &(ubq->io_cmd_buf[tag * sizeof(struct ublksrv_io_desc)]); 314 } 315 316 static inline char *ublk_queue_cmd_buf(struct ublk_device *ub, int q_id) 317 { 318 return ublk_get_queue(ub, q_id)->io_cmd_buf; 319 } 320 321 static inline int ublk_queue_cmd_buf_size(struct ublk_device *ub, int q_id) 322 { 323 struct ublk_queue *ubq = ublk_get_queue(ub, q_id); 324 325 return round_up(ubq->q_depth * sizeof(struct ublksrv_io_desc), 326 PAGE_SIZE); 327 } 328 329 static inline bool ublk_queue_can_use_recovery_reissue( 330 struct ublk_queue *ubq) 331 { 332 if ((ubq->flags & UBLK_F_USER_RECOVERY) && 333 (ubq->flags & UBLK_F_USER_RECOVERY_REISSUE)) 334 return true; 335 return false; 336 } 337 338 static inline bool ublk_queue_can_use_recovery( 339 struct ublk_queue *ubq) 340 { 341 if (ubq->flags & UBLK_F_USER_RECOVERY) 342 return true; 343 return false; 344 } 345 346 static inline bool ublk_can_use_recovery(struct ublk_device *ub) 347 { 348 if (ub->dev_info.flags & UBLK_F_USER_RECOVERY) 349 return true; 350 return false; 351 } 352 353 static void ublk_free_disk(struct gendisk *disk) 354 { 355 struct ublk_device *ub = disk->private_data; 356 357 clear_bit(UB_STATE_USED, &ub->state); 358 put_device(&ub->cdev_dev); 359 } 360 361 static const struct block_device_operations ub_fops = { 362 .owner = THIS_MODULE, 363 .free_disk = ublk_free_disk, 364 }; 365 366 #define UBLK_MAX_PIN_PAGES 32 367 368 struct ublk_map_data { 369 const struct ublk_queue *ubq; 370 const struct request *rq; 371 const struct ublk_io *io; 372 unsigned max_bytes; 373 }; 374 375 struct ublk_io_iter { 376 struct page *pages[UBLK_MAX_PIN_PAGES]; 377 unsigned pg_off; /* offset in the 1st page in pages */ 378 int nr_pages; /* how many page pointers in pages */ 379 struct bio *bio; 380 struct bvec_iter iter; 381 }; 382 383 static inline unsigned ublk_copy_io_pages(struct ublk_io_iter *data, 384 unsigned max_bytes, bool to_vm) 385 { 386 const unsigned total = min_t(unsigned, max_bytes, 387 PAGE_SIZE - data->pg_off + 388 ((data->nr_pages - 1) << PAGE_SHIFT)); 389 unsigned done = 0; 390 unsigned pg_idx = 0; 391 392 while (done < total) { 393 struct bio_vec bv = bio_iter_iovec(data->bio, data->iter); 394 const unsigned int bytes = min3(bv.bv_len, total - done, 395 (unsigned)(PAGE_SIZE - data->pg_off)); 396 void *bv_buf = bvec_kmap_local(&bv); 397 void *pg_buf = kmap_local_page(data->pages[pg_idx]); 398 399 if (to_vm) 400 memcpy(pg_buf + data->pg_off, bv_buf, bytes); 401 else 402 memcpy(bv_buf, pg_buf + data->pg_off, bytes); 403 404 kunmap_local(pg_buf); 405 kunmap_local(bv_buf); 406 407 /* advance page array */ 408 data->pg_off += bytes; 409 if (data->pg_off == PAGE_SIZE) { 410 pg_idx += 1; 411 data->pg_off = 0; 412 } 413 414 done += bytes; 415 416 /* advance bio */ 417 bio_advance_iter_single(data->bio, &data->iter, bytes); 418 if (!data->iter.bi_size) { 419 data->bio = data->bio->bi_next; 420 if (data->bio == NULL) 421 break; 422 data->iter = data->bio->bi_iter; 423 } 424 } 425 426 return done; 427 } 428 429 static inline int ublk_copy_user_pages(struct ublk_map_data *data, 430 bool to_vm) 431 { 432 const unsigned int gup_flags = to_vm ? FOLL_WRITE : 0; 433 const unsigned long start_vm = data->io->addr; 434 unsigned int done = 0; 435 struct ublk_io_iter iter = { 436 .pg_off = start_vm & (PAGE_SIZE - 1), 437 .bio = data->rq->bio, 438 .iter = data->rq->bio->bi_iter, 439 }; 440 const unsigned int nr_pages = round_up(data->max_bytes + 441 (start_vm & (PAGE_SIZE - 1)), PAGE_SIZE) >> PAGE_SHIFT; 442 443 while (done < nr_pages) { 444 const unsigned to_pin = min_t(unsigned, UBLK_MAX_PIN_PAGES, 445 nr_pages - done); 446 unsigned i, len; 447 448 iter.nr_pages = get_user_pages_fast(start_vm + 449 (done << PAGE_SHIFT), to_pin, gup_flags, 450 iter.pages); 451 if (iter.nr_pages <= 0) 452 return done == 0 ? iter.nr_pages : done; 453 len = ublk_copy_io_pages(&iter, data->max_bytes, to_vm); 454 for (i = 0; i < iter.nr_pages; i++) { 455 if (to_vm) 456 set_page_dirty(iter.pages[i]); 457 put_page(iter.pages[i]); 458 } 459 data->max_bytes -= len; 460 done += iter.nr_pages; 461 } 462 463 return done; 464 } 465 466 static int ublk_map_io(const struct ublk_queue *ubq, const struct request *req, 467 struct ublk_io *io) 468 { 469 const unsigned int rq_bytes = blk_rq_bytes(req); 470 /* 471 * no zero copy, we delay copy WRITE request data into ublksrv 472 * context and the big benefit is that pinning pages in current 473 * context is pretty fast, see ublk_pin_user_pages 474 */ 475 if (req_op(req) != REQ_OP_WRITE && req_op(req) != REQ_OP_FLUSH) 476 return rq_bytes; 477 478 if (ublk_rq_has_data(req)) { 479 struct ublk_map_data data = { 480 .ubq = ubq, 481 .rq = req, 482 .io = io, 483 .max_bytes = rq_bytes, 484 }; 485 486 ublk_copy_user_pages(&data, true); 487 488 return rq_bytes - data.max_bytes; 489 } 490 return rq_bytes; 491 } 492 493 static int ublk_unmap_io(const struct ublk_queue *ubq, 494 const struct request *req, 495 struct ublk_io *io) 496 { 497 const unsigned int rq_bytes = blk_rq_bytes(req); 498 499 if (req_op(req) == REQ_OP_READ && ublk_rq_has_data(req)) { 500 struct ublk_map_data data = { 501 .ubq = ubq, 502 .rq = req, 503 .io = io, 504 .max_bytes = io->res, 505 }; 506 507 WARN_ON_ONCE(io->res > rq_bytes); 508 509 ublk_copy_user_pages(&data, false); 510 511 return io->res - data.max_bytes; 512 } 513 return rq_bytes; 514 } 515 516 static inline unsigned int ublk_req_build_flags(struct request *req) 517 { 518 unsigned flags = 0; 519 520 if (req->cmd_flags & REQ_FAILFAST_DEV) 521 flags |= UBLK_IO_F_FAILFAST_DEV; 522 523 if (req->cmd_flags & REQ_FAILFAST_TRANSPORT) 524 flags |= UBLK_IO_F_FAILFAST_TRANSPORT; 525 526 if (req->cmd_flags & REQ_FAILFAST_DRIVER) 527 flags |= UBLK_IO_F_FAILFAST_DRIVER; 528 529 if (req->cmd_flags & REQ_META) 530 flags |= UBLK_IO_F_META; 531 532 if (req->cmd_flags & REQ_FUA) 533 flags |= UBLK_IO_F_FUA; 534 535 if (req->cmd_flags & REQ_NOUNMAP) 536 flags |= UBLK_IO_F_NOUNMAP; 537 538 if (req->cmd_flags & REQ_SWAP) 539 flags |= UBLK_IO_F_SWAP; 540 541 return flags; 542 } 543 544 static blk_status_t ublk_setup_iod(struct ublk_queue *ubq, struct request *req) 545 { 546 struct ublksrv_io_desc *iod = ublk_get_iod(ubq, req->tag); 547 struct ublk_io *io = &ubq->ios[req->tag]; 548 u32 ublk_op; 549 550 switch (req_op(req)) { 551 case REQ_OP_READ: 552 ublk_op = UBLK_IO_OP_READ; 553 break; 554 case REQ_OP_WRITE: 555 ublk_op = UBLK_IO_OP_WRITE; 556 break; 557 case REQ_OP_FLUSH: 558 ublk_op = UBLK_IO_OP_FLUSH; 559 break; 560 case REQ_OP_DISCARD: 561 ublk_op = UBLK_IO_OP_DISCARD; 562 break; 563 case REQ_OP_WRITE_ZEROES: 564 ublk_op = UBLK_IO_OP_WRITE_ZEROES; 565 break; 566 default: 567 return BLK_STS_IOERR; 568 } 569 570 /* need to translate since kernel may change */ 571 iod->op_flags = ublk_op | ublk_req_build_flags(req); 572 iod->nr_sectors = blk_rq_sectors(req); 573 iod->start_sector = blk_rq_pos(req); 574 iod->addr = io->addr; 575 576 return BLK_STS_OK; 577 } 578 579 static inline struct ublk_uring_cmd_pdu *ublk_get_uring_cmd_pdu( 580 struct io_uring_cmd *ioucmd) 581 { 582 return (struct ublk_uring_cmd_pdu *)&ioucmd->pdu; 583 } 584 585 static inline bool ubq_daemon_is_dying(struct ublk_queue *ubq) 586 { 587 return ubq->ubq_daemon->flags & PF_EXITING; 588 } 589 590 /* todo: handle partial completion */ 591 static void ublk_complete_rq(struct request *req) 592 { 593 struct ublk_queue *ubq = req->mq_hctx->driver_data; 594 struct ublk_io *io = &ubq->ios[req->tag]; 595 unsigned int unmapped_bytes; 596 597 /* failed read IO if nothing is read */ 598 if (!io->res && req_op(req) == REQ_OP_READ) 599 io->res = -EIO; 600 601 if (io->res < 0) { 602 blk_mq_end_request(req, errno_to_blk_status(io->res)); 603 return; 604 } 605 606 /* 607 * FLUSH or DISCARD usually won't return bytes returned, so end them 608 * directly. 609 * 610 * Both the two needn't unmap. 611 */ 612 if (req_op(req) != REQ_OP_READ && req_op(req) != REQ_OP_WRITE) { 613 blk_mq_end_request(req, BLK_STS_OK); 614 return; 615 } 616 617 /* for READ request, writing data in iod->addr to rq buffers */ 618 unmapped_bytes = ublk_unmap_io(ubq, req, io); 619 620 /* 621 * Extremely impossible since we got data filled in just before 622 * 623 * Re-read simply for this unlikely case. 624 */ 625 if (unlikely(unmapped_bytes < io->res)) 626 io->res = unmapped_bytes; 627 628 if (blk_update_request(req, BLK_STS_OK, io->res)) 629 blk_mq_requeue_request(req, true); 630 else 631 __blk_mq_end_request(req, BLK_STS_OK); 632 } 633 634 /* 635 * Since __ublk_rq_task_work always fails requests immediately during 636 * exiting, __ublk_fail_req() is only called from abort context during 637 * exiting. So lock is unnecessary. 638 * 639 * Also aborting may not be started yet, keep in mind that one failed 640 * request may be issued by block layer again. 641 */ 642 static void __ublk_fail_req(struct ublk_queue *ubq, struct ublk_io *io, 643 struct request *req) 644 { 645 WARN_ON_ONCE(io->flags & UBLK_IO_FLAG_ACTIVE); 646 647 if (!(io->flags & UBLK_IO_FLAG_ABORTED)) { 648 io->flags |= UBLK_IO_FLAG_ABORTED; 649 if (ublk_queue_can_use_recovery_reissue(ubq)) 650 blk_mq_requeue_request(req, false); 651 else 652 blk_mq_end_request(req, BLK_STS_IOERR); 653 } 654 } 655 656 static void ubq_complete_io_cmd(struct ublk_io *io, int res) 657 { 658 /* mark this cmd owned by ublksrv */ 659 io->flags |= UBLK_IO_FLAG_OWNED_BY_SRV; 660 661 /* 662 * clear ACTIVE since we are done with this sqe/cmd slot 663 * We can only accept io cmd in case of being not active. 664 */ 665 io->flags &= ~UBLK_IO_FLAG_ACTIVE; 666 667 /* tell ublksrv one io request is coming */ 668 io_uring_cmd_done(io->cmd, res, 0); 669 } 670 671 #define UBLK_REQUEUE_DELAY_MS 3 672 673 static inline void __ublk_abort_rq(struct ublk_queue *ubq, 674 struct request *rq) 675 { 676 /* We cannot process this rq so just requeue it. */ 677 if (ublk_queue_can_use_recovery(ubq)) 678 blk_mq_requeue_request(rq, false); 679 else 680 blk_mq_end_request(rq, BLK_STS_IOERR); 681 682 mod_delayed_work(system_wq, &ubq->dev->monitor_work, 0); 683 } 684 685 static inline void __ublk_rq_task_work(struct request *req) 686 { 687 struct ublk_queue *ubq = req->mq_hctx->driver_data; 688 int tag = req->tag; 689 struct ublk_io *io = &ubq->ios[tag]; 690 unsigned int mapped_bytes; 691 692 pr_devel("%s: complete: op %d, qid %d tag %d io_flags %x addr %llx\n", 693 __func__, io->cmd->cmd_op, ubq->q_id, req->tag, io->flags, 694 ublk_get_iod(ubq, req->tag)->addr); 695 696 /* 697 * Task is exiting if either: 698 * 699 * (1) current != ubq_daemon. 700 * io_uring_cmd_complete_in_task() tries to run task_work 701 * in a workqueue if ubq_daemon(cmd's task) is PF_EXITING. 702 * 703 * (2) current->flags & PF_EXITING. 704 */ 705 if (unlikely(current != ubq->ubq_daemon || current->flags & PF_EXITING)) { 706 __ublk_abort_rq(ubq, req); 707 return; 708 } 709 710 if (ublk_need_get_data(ubq) && 711 (req_op(req) == REQ_OP_WRITE || 712 req_op(req) == REQ_OP_FLUSH)) { 713 /* 714 * We have not handled UBLK_IO_NEED_GET_DATA command yet, 715 * so immepdately pass UBLK_IO_RES_NEED_GET_DATA to ublksrv 716 * and notify it. 717 */ 718 if (!(io->flags & UBLK_IO_FLAG_NEED_GET_DATA)) { 719 io->flags |= UBLK_IO_FLAG_NEED_GET_DATA; 720 pr_devel("%s: need get data. op %d, qid %d tag %d io_flags %x\n", 721 __func__, io->cmd->cmd_op, ubq->q_id, 722 req->tag, io->flags); 723 ubq_complete_io_cmd(io, UBLK_IO_RES_NEED_GET_DATA); 724 return; 725 } 726 /* 727 * We have handled UBLK_IO_NEED_GET_DATA command, 728 * so clear UBLK_IO_FLAG_NEED_GET_DATA now and just 729 * do the copy work. 730 */ 731 io->flags &= ~UBLK_IO_FLAG_NEED_GET_DATA; 732 /* update iod->addr because ublksrv may have passed a new io buffer */ 733 ublk_get_iod(ubq, req->tag)->addr = io->addr; 734 pr_devel("%s: update iod->addr: op %d, qid %d tag %d io_flags %x addr %llx\n", 735 __func__, io->cmd->cmd_op, ubq->q_id, req->tag, io->flags, 736 ublk_get_iod(ubq, req->tag)->addr); 737 } 738 739 mapped_bytes = ublk_map_io(ubq, req, io); 740 741 /* partially mapped, update io descriptor */ 742 if (unlikely(mapped_bytes != blk_rq_bytes(req))) { 743 /* 744 * Nothing mapped, retry until we succeed. 745 * 746 * We may never succeed in mapping any bytes here because 747 * of OOM. TODO: reserve one buffer with single page pinned 748 * for providing forward progress guarantee. 749 */ 750 if (unlikely(!mapped_bytes)) { 751 blk_mq_requeue_request(req, false); 752 blk_mq_delay_kick_requeue_list(req->q, 753 UBLK_REQUEUE_DELAY_MS); 754 return; 755 } 756 757 ublk_get_iod(ubq, req->tag)->nr_sectors = 758 mapped_bytes >> 9; 759 } 760 761 ubq_complete_io_cmd(io, UBLK_IO_RES_OK); 762 } 763 764 static void ublk_rq_task_work_cb(struct io_uring_cmd *cmd) 765 { 766 struct ublk_uring_cmd_pdu *pdu = ublk_get_uring_cmd_pdu(cmd); 767 768 __ublk_rq_task_work(pdu->req); 769 } 770 771 static void ublk_rq_task_work_fn(struct callback_head *work) 772 { 773 struct ublk_rq_data *data = container_of(work, 774 struct ublk_rq_data, work); 775 struct request *req = blk_mq_rq_from_pdu(data); 776 777 __ublk_rq_task_work(req); 778 } 779 780 static blk_status_t ublk_queue_rq(struct blk_mq_hw_ctx *hctx, 781 const struct blk_mq_queue_data *bd) 782 { 783 struct ublk_queue *ubq = hctx->driver_data; 784 struct request *rq = bd->rq; 785 blk_status_t res; 786 787 /* fill iod to slot in io cmd buffer */ 788 res = ublk_setup_iod(ubq, rq); 789 if (unlikely(res != BLK_STS_OK)) 790 return BLK_STS_IOERR; 791 /* With recovery feature enabled, force_abort is set in 792 * ublk_stop_dev() before calling del_gendisk(). We have to 793 * abort all requeued and new rqs here to let del_gendisk() 794 * move on. Besides, we cannot not call io_uring_cmd_complete_in_task() 795 * to avoid UAF on io_uring ctx. 796 * 797 * Note: force_abort is guaranteed to be seen because it is set 798 * before request queue is unqiuesced. 799 */ 800 if (ublk_queue_can_use_recovery(ubq) && unlikely(ubq->force_abort)) 801 return BLK_STS_IOERR; 802 803 blk_mq_start_request(bd->rq); 804 805 if (unlikely(ubq_daemon_is_dying(ubq))) { 806 fail: 807 __ublk_abort_rq(ubq, rq); 808 return BLK_STS_OK; 809 } 810 811 if (ublk_can_use_task_work(ubq)) { 812 struct ublk_rq_data *data = blk_mq_rq_to_pdu(rq); 813 enum task_work_notify_mode notify_mode = bd->last ? 814 TWA_SIGNAL_NO_IPI : TWA_NONE; 815 816 if (task_work_add(ubq->ubq_daemon, &data->work, notify_mode)) 817 goto fail; 818 } else { 819 struct ublk_io *io = &ubq->ios[rq->tag]; 820 struct io_uring_cmd *cmd = io->cmd; 821 struct ublk_uring_cmd_pdu *pdu = ublk_get_uring_cmd_pdu(cmd); 822 823 /* 824 * If the check pass, we know that this is a re-issued request aborted 825 * previously in monitor_work because the ubq_daemon(cmd's task) is 826 * PF_EXITING. We cannot call io_uring_cmd_complete_in_task() anymore 827 * because this ioucmd's io_uring context may be freed now if no inflight 828 * ioucmd exists. Otherwise we may cause null-deref in ctx->fallback_work. 829 * 830 * Note: monitor_work sets UBLK_IO_FLAG_ABORTED and ends this request(releasing 831 * the tag). Then the request is re-started(allocating the tag) and we are here. 832 * Since releasing/allocating a tag implies smp_mb(), finding UBLK_IO_FLAG_ABORTED 833 * guarantees that here is a re-issued request aborted previously. 834 */ 835 if ((io->flags & UBLK_IO_FLAG_ABORTED)) 836 goto fail; 837 838 pdu->req = rq; 839 io_uring_cmd_complete_in_task(cmd, ublk_rq_task_work_cb); 840 } 841 842 return BLK_STS_OK; 843 } 844 845 static void ublk_commit_rqs(struct blk_mq_hw_ctx *hctx) 846 { 847 struct ublk_queue *ubq = hctx->driver_data; 848 849 if (ublk_can_use_task_work(ubq)) 850 __set_notify_signal(ubq->ubq_daemon); 851 } 852 853 static int ublk_init_hctx(struct blk_mq_hw_ctx *hctx, void *driver_data, 854 unsigned int hctx_idx) 855 { 856 struct ublk_device *ub = driver_data; 857 struct ublk_queue *ubq = ublk_get_queue(ub, hctx->queue_num); 858 859 hctx->driver_data = ubq; 860 return 0; 861 } 862 863 static int ublk_init_rq(struct blk_mq_tag_set *set, struct request *req, 864 unsigned int hctx_idx, unsigned int numa_node) 865 { 866 struct ublk_rq_data *data = blk_mq_rq_to_pdu(req); 867 868 init_task_work(&data->work, ublk_rq_task_work_fn); 869 return 0; 870 } 871 872 static const struct blk_mq_ops ublk_mq_ops = { 873 .queue_rq = ublk_queue_rq, 874 .commit_rqs = ublk_commit_rqs, 875 .init_hctx = ublk_init_hctx, 876 .init_request = ublk_init_rq, 877 }; 878 879 static int ublk_ch_open(struct inode *inode, struct file *filp) 880 { 881 struct ublk_device *ub = container_of(inode->i_cdev, 882 struct ublk_device, cdev); 883 884 if (test_and_set_bit(UB_STATE_OPEN, &ub->state)) 885 return -EBUSY; 886 filp->private_data = ub; 887 return 0; 888 } 889 890 static int ublk_ch_release(struct inode *inode, struct file *filp) 891 { 892 struct ublk_device *ub = filp->private_data; 893 894 clear_bit(UB_STATE_OPEN, &ub->state); 895 return 0; 896 } 897 898 /* map pre-allocated per-queue cmd buffer to ublksrv daemon */ 899 static int ublk_ch_mmap(struct file *filp, struct vm_area_struct *vma) 900 { 901 struct ublk_device *ub = filp->private_data; 902 size_t sz = vma->vm_end - vma->vm_start; 903 unsigned max_sz = UBLK_MAX_QUEUE_DEPTH * sizeof(struct ublksrv_io_desc); 904 unsigned long pfn, end, phys_off = vma->vm_pgoff << PAGE_SHIFT; 905 int q_id, ret = 0; 906 907 spin_lock(&ub->mm_lock); 908 if (!ub->mm) 909 ub->mm = current->mm; 910 if (current->mm != ub->mm) 911 ret = -EINVAL; 912 spin_unlock(&ub->mm_lock); 913 914 if (ret) 915 return ret; 916 917 if (vma->vm_flags & VM_WRITE) 918 return -EPERM; 919 920 end = UBLKSRV_CMD_BUF_OFFSET + ub->dev_info.nr_hw_queues * max_sz; 921 if (phys_off < UBLKSRV_CMD_BUF_OFFSET || phys_off >= end) 922 return -EINVAL; 923 924 q_id = (phys_off - UBLKSRV_CMD_BUF_OFFSET) / max_sz; 925 pr_devel("%s: qid %d, pid %d, addr %lx pg_off %lx sz %lu\n", 926 __func__, q_id, current->pid, vma->vm_start, 927 phys_off, (unsigned long)sz); 928 929 if (sz != ublk_queue_cmd_buf_size(ub, q_id)) 930 return -EINVAL; 931 932 pfn = virt_to_phys(ublk_queue_cmd_buf(ub, q_id)) >> PAGE_SHIFT; 933 return remap_pfn_range(vma, vma->vm_start, pfn, sz, vma->vm_page_prot); 934 } 935 936 static void ublk_commit_completion(struct ublk_device *ub, 937 struct ublksrv_io_cmd *ub_cmd) 938 { 939 u32 qid = ub_cmd->q_id, tag = ub_cmd->tag; 940 struct ublk_queue *ubq = ublk_get_queue(ub, qid); 941 struct ublk_io *io = &ubq->ios[tag]; 942 struct request *req; 943 944 /* now this cmd slot is owned by nbd driver */ 945 io->flags &= ~UBLK_IO_FLAG_OWNED_BY_SRV; 946 io->res = ub_cmd->result; 947 948 /* find the io request and complete */ 949 req = blk_mq_tag_to_rq(ub->tag_set.tags[qid], tag); 950 951 if (req && likely(!blk_should_fake_timeout(req->q))) 952 ublk_complete_rq(req); 953 } 954 955 /* 956 * When ->ubq_daemon is exiting, either new request is ended immediately, 957 * or any queued io command is drained, so it is safe to abort queue 958 * lockless 959 */ 960 static void ublk_abort_queue(struct ublk_device *ub, struct ublk_queue *ubq) 961 { 962 int i; 963 964 if (!ublk_get_device(ub)) 965 return; 966 967 for (i = 0; i < ubq->q_depth; i++) { 968 struct ublk_io *io = &ubq->ios[i]; 969 970 if (!(io->flags & UBLK_IO_FLAG_ACTIVE)) { 971 struct request *rq; 972 973 /* 974 * Either we fail the request or ublk_rq_task_work_fn 975 * will do it 976 */ 977 rq = blk_mq_tag_to_rq(ub->tag_set.tags[ubq->q_id], i); 978 if (rq) 979 __ublk_fail_req(ubq, io, rq); 980 } 981 } 982 ublk_put_device(ub); 983 } 984 985 static void ublk_daemon_monitor_work(struct work_struct *work) 986 { 987 struct ublk_device *ub = 988 container_of(work, struct ublk_device, monitor_work.work); 989 int i; 990 991 for (i = 0; i < ub->dev_info.nr_hw_queues; i++) { 992 struct ublk_queue *ubq = ublk_get_queue(ub, i); 993 994 if (ubq_daemon_is_dying(ubq)) { 995 if (ublk_queue_can_use_recovery(ubq)) 996 schedule_work(&ub->quiesce_work); 997 else 998 schedule_work(&ub->stop_work); 999 1000 /* abort queue is for making forward progress */ 1001 ublk_abort_queue(ub, ubq); 1002 } 1003 } 1004 1005 /* 1006 * We can't schedule monitor work after ub's state is not UBLK_S_DEV_LIVE. 1007 * after ublk_remove() or __ublk_quiesce_dev() is started. 1008 * 1009 * No need ub->mutex, monitor work are canceled after state is marked 1010 * as not LIVE, so new state is observed reliably. 1011 */ 1012 if (ub->dev_info.state == UBLK_S_DEV_LIVE) 1013 schedule_delayed_work(&ub->monitor_work, 1014 UBLK_DAEMON_MONITOR_PERIOD); 1015 } 1016 1017 static inline bool ublk_queue_ready(struct ublk_queue *ubq) 1018 { 1019 return ubq->nr_io_ready == ubq->q_depth; 1020 } 1021 1022 static void ublk_cancel_queue(struct ublk_queue *ubq) 1023 { 1024 int i; 1025 1026 if (!ublk_queue_ready(ubq)) 1027 return; 1028 1029 for (i = 0; i < ubq->q_depth; i++) { 1030 struct ublk_io *io = &ubq->ios[i]; 1031 1032 if (io->flags & UBLK_IO_FLAG_ACTIVE) 1033 io_uring_cmd_done(io->cmd, UBLK_IO_RES_ABORT, 0); 1034 } 1035 1036 /* all io commands are canceled */ 1037 ubq->nr_io_ready = 0; 1038 } 1039 1040 /* Cancel all pending commands, must be called after del_gendisk() returns */ 1041 static void ublk_cancel_dev(struct ublk_device *ub) 1042 { 1043 int i; 1044 1045 for (i = 0; i < ub->dev_info.nr_hw_queues; i++) 1046 ublk_cancel_queue(ublk_get_queue(ub, i)); 1047 } 1048 1049 static bool ublk_check_inflight_rq(struct request *rq, void *data) 1050 { 1051 bool *idle = data; 1052 1053 if (blk_mq_request_started(rq)) { 1054 *idle = false; 1055 return false; 1056 } 1057 return true; 1058 } 1059 1060 static void ublk_wait_tagset_rqs_idle(struct ublk_device *ub) 1061 { 1062 bool idle; 1063 1064 WARN_ON_ONCE(!blk_queue_quiesced(ub->ub_disk->queue)); 1065 while (true) { 1066 idle = true; 1067 blk_mq_tagset_busy_iter(&ub->tag_set, 1068 ublk_check_inflight_rq, &idle); 1069 if (idle) 1070 break; 1071 msleep(UBLK_REQUEUE_DELAY_MS); 1072 } 1073 } 1074 1075 static void __ublk_quiesce_dev(struct ublk_device *ub) 1076 { 1077 pr_devel("%s: quiesce ub: dev_id %d state %s\n", 1078 __func__, ub->dev_info.dev_id, 1079 ub->dev_info.state == UBLK_S_DEV_LIVE ? 1080 "LIVE" : "QUIESCED"); 1081 blk_mq_quiesce_queue(ub->ub_disk->queue); 1082 ublk_wait_tagset_rqs_idle(ub); 1083 ub->dev_info.state = UBLK_S_DEV_QUIESCED; 1084 ublk_cancel_dev(ub); 1085 /* we are going to release task_struct of ubq_daemon and resets 1086 * ->ubq_daemon to NULL. So in monitor_work, check on ubq_daemon causes UAF. 1087 * Besides, monitor_work is not necessary in QUIESCED state since we have 1088 * already scheduled quiesce_work and quiesced all ubqs. 1089 * 1090 * Do not let monitor_work schedule itself if state it QUIESCED. And we cancel 1091 * it here and re-schedule it in END_USER_RECOVERY to avoid UAF. 1092 */ 1093 cancel_delayed_work_sync(&ub->monitor_work); 1094 } 1095 1096 static void ublk_quiesce_work_fn(struct work_struct *work) 1097 { 1098 struct ublk_device *ub = 1099 container_of(work, struct ublk_device, quiesce_work); 1100 1101 mutex_lock(&ub->mutex); 1102 if (ub->dev_info.state != UBLK_S_DEV_LIVE) 1103 goto unlock; 1104 __ublk_quiesce_dev(ub); 1105 unlock: 1106 mutex_unlock(&ub->mutex); 1107 } 1108 1109 static void ublk_unquiesce_dev(struct ublk_device *ub) 1110 { 1111 int i; 1112 1113 pr_devel("%s: unquiesce ub: dev_id %d state %s\n", 1114 __func__, ub->dev_info.dev_id, 1115 ub->dev_info.state == UBLK_S_DEV_LIVE ? 1116 "LIVE" : "QUIESCED"); 1117 /* quiesce_work has run. We let requeued rqs be aborted 1118 * before running fallback_wq. "force_abort" must be seen 1119 * after request queue is unqiuesced. Then del_gendisk() 1120 * can move on. 1121 */ 1122 for (i = 0; i < ub->dev_info.nr_hw_queues; i++) 1123 ublk_get_queue(ub, i)->force_abort = true; 1124 1125 blk_mq_unquiesce_queue(ub->ub_disk->queue); 1126 /* We may have requeued some rqs in ublk_quiesce_queue() */ 1127 blk_mq_kick_requeue_list(ub->ub_disk->queue); 1128 } 1129 1130 static void ublk_stop_dev(struct ublk_device *ub) 1131 { 1132 mutex_lock(&ub->mutex); 1133 if (ub->dev_info.state == UBLK_S_DEV_DEAD) 1134 goto unlock; 1135 if (ublk_can_use_recovery(ub)) { 1136 if (ub->dev_info.state == UBLK_S_DEV_LIVE) 1137 __ublk_quiesce_dev(ub); 1138 ublk_unquiesce_dev(ub); 1139 } 1140 del_gendisk(ub->ub_disk); 1141 ub->dev_info.state = UBLK_S_DEV_DEAD; 1142 ub->dev_info.ublksrv_pid = -1; 1143 put_disk(ub->ub_disk); 1144 ub->ub_disk = NULL; 1145 unlock: 1146 ublk_cancel_dev(ub); 1147 mutex_unlock(&ub->mutex); 1148 cancel_delayed_work_sync(&ub->monitor_work); 1149 } 1150 1151 /* device can only be started after all IOs are ready */ 1152 static void ublk_mark_io_ready(struct ublk_device *ub, struct ublk_queue *ubq) 1153 { 1154 mutex_lock(&ub->mutex); 1155 ubq->nr_io_ready++; 1156 if (ublk_queue_ready(ubq)) { 1157 ubq->ubq_daemon = current; 1158 get_task_struct(ubq->ubq_daemon); 1159 ub->nr_queues_ready++; 1160 } 1161 if (ub->nr_queues_ready == ub->dev_info.nr_hw_queues) 1162 complete_all(&ub->completion); 1163 mutex_unlock(&ub->mutex); 1164 } 1165 1166 static void ublk_handle_need_get_data(struct ublk_device *ub, int q_id, 1167 int tag, struct io_uring_cmd *cmd) 1168 { 1169 struct ublk_queue *ubq = ublk_get_queue(ub, q_id); 1170 struct request *req = blk_mq_tag_to_rq(ub->tag_set.tags[q_id], tag); 1171 1172 if (ublk_can_use_task_work(ubq)) { 1173 struct ublk_rq_data *data = blk_mq_rq_to_pdu(req); 1174 1175 /* should not fail since we call it just in ubq->ubq_daemon */ 1176 task_work_add(ubq->ubq_daemon, &data->work, TWA_SIGNAL_NO_IPI); 1177 } else { 1178 struct ublk_uring_cmd_pdu *pdu = ublk_get_uring_cmd_pdu(cmd); 1179 1180 pdu->req = req; 1181 io_uring_cmd_complete_in_task(cmd, ublk_rq_task_work_cb); 1182 } 1183 } 1184 1185 static int ublk_ch_uring_cmd(struct io_uring_cmd *cmd, unsigned int issue_flags) 1186 { 1187 struct ublksrv_io_cmd *ub_cmd = (struct ublksrv_io_cmd *)cmd->cmd; 1188 struct ublk_device *ub = cmd->file->private_data; 1189 struct ublk_queue *ubq; 1190 struct ublk_io *io; 1191 u32 cmd_op = cmd->cmd_op; 1192 unsigned tag = ub_cmd->tag; 1193 int ret = -EINVAL; 1194 1195 pr_devel("%s: received: cmd op %d queue %d tag %d result %d\n", 1196 __func__, cmd->cmd_op, ub_cmd->q_id, tag, 1197 ub_cmd->result); 1198 1199 if (!(issue_flags & IO_URING_F_SQE128)) 1200 goto out; 1201 1202 if (ub_cmd->q_id >= ub->dev_info.nr_hw_queues) 1203 goto out; 1204 1205 ubq = ublk_get_queue(ub, ub_cmd->q_id); 1206 if (!ubq || ub_cmd->q_id != ubq->q_id) 1207 goto out; 1208 1209 if (ubq->ubq_daemon && ubq->ubq_daemon != current) 1210 goto out; 1211 1212 if (tag >= ubq->q_depth) 1213 goto out; 1214 1215 io = &ubq->ios[tag]; 1216 1217 /* there is pending io cmd, something must be wrong */ 1218 if (io->flags & UBLK_IO_FLAG_ACTIVE) { 1219 ret = -EBUSY; 1220 goto out; 1221 } 1222 1223 /* 1224 * ensure that the user issues UBLK_IO_NEED_GET_DATA 1225 * iff the driver have set the UBLK_IO_FLAG_NEED_GET_DATA. 1226 */ 1227 if ((!!(io->flags & UBLK_IO_FLAG_NEED_GET_DATA)) 1228 ^ (cmd_op == UBLK_IO_NEED_GET_DATA)) 1229 goto out; 1230 1231 switch (cmd_op) { 1232 case UBLK_IO_FETCH_REQ: 1233 /* UBLK_IO_FETCH_REQ is only allowed before queue is setup */ 1234 if (ublk_queue_ready(ubq)) { 1235 ret = -EBUSY; 1236 goto out; 1237 } 1238 /* 1239 * The io is being handled by server, so COMMIT_RQ is expected 1240 * instead of FETCH_REQ 1241 */ 1242 if (io->flags & UBLK_IO_FLAG_OWNED_BY_SRV) 1243 goto out; 1244 /* FETCH_RQ has to provide IO buffer */ 1245 if (!ub_cmd->addr) 1246 goto out; 1247 io->cmd = cmd; 1248 io->flags |= UBLK_IO_FLAG_ACTIVE; 1249 io->addr = ub_cmd->addr; 1250 1251 ublk_mark_io_ready(ub, ubq); 1252 break; 1253 case UBLK_IO_COMMIT_AND_FETCH_REQ: 1254 /* FETCH_RQ has to provide IO buffer */ 1255 if (!ub_cmd->addr) 1256 goto out; 1257 if (!(io->flags & UBLK_IO_FLAG_OWNED_BY_SRV)) 1258 goto out; 1259 io->addr = ub_cmd->addr; 1260 io->flags |= UBLK_IO_FLAG_ACTIVE; 1261 io->cmd = cmd; 1262 ublk_commit_completion(ub, ub_cmd); 1263 break; 1264 case UBLK_IO_NEED_GET_DATA: 1265 if (!(io->flags & UBLK_IO_FLAG_OWNED_BY_SRV)) 1266 goto out; 1267 io->addr = ub_cmd->addr; 1268 io->cmd = cmd; 1269 io->flags |= UBLK_IO_FLAG_ACTIVE; 1270 ublk_handle_need_get_data(ub, ub_cmd->q_id, ub_cmd->tag, cmd); 1271 break; 1272 default: 1273 goto out; 1274 } 1275 return -EIOCBQUEUED; 1276 1277 out: 1278 io_uring_cmd_done(cmd, ret, 0); 1279 pr_devel("%s: complete: cmd op %d, tag %d ret %x io_flags %x\n", 1280 __func__, cmd_op, tag, ret, io->flags); 1281 return -EIOCBQUEUED; 1282 } 1283 1284 static const struct file_operations ublk_ch_fops = { 1285 .owner = THIS_MODULE, 1286 .open = ublk_ch_open, 1287 .release = ublk_ch_release, 1288 .llseek = no_llseek, 1289 .uring_cmd = ublk_ch_uring_cmd, 1290 .mmap = ublk_ch_mmap, 1291 }; 1292 1293 static void ublk_deinit_queue(struct ublk_device *ub, int q_id) 1294 { 1295 int size = ublk_queue_cmd_buf_size(ub, q_id); 1296 struct ublk_queue *ubq = ublk_get_queue(ub, q_id); 1297 1298 if (ubq->ubq_daemon) 1299 put_task_struct(ubq->ubq_daemon); 1300 if (ubq->io_cmd_buf) 1301 free_pages((unsigned long)ubq->io_cmd_buf, get_order(size)); 1302 } 1303 1304 static int ublk_init_queue(struct ublk_device *ub, int q_id) 1305 { 1306 struct ublk_queue *ubq = ublk_get_queue(ub, q_id); 1307 gfp_t gfp_flags = GFP_KERNEL | __GFP_ZERO; 1308 void *ptr; 1309 int size; 1310 1311 ubq->flags = ub->dev_info.flags; 1312 ubq->q_id = q_id; 1313 ubq->q_depth = ub->dev_info.queue_depth; 1314 size = ublk_queue_cmd_buf_size(ub, q_id); 1315 1316 ptr = (void *) __get_free_pages(gfp_flags, get_order(size)); 1317 if (!ptr) 1318 return -ENOMEM; 1319 1320 ubq->io_cmd_buf = ptr; 1321 ubq->dev = ub; 1322 return 0; 1323 } 1324 1325 static void ublk_deinit_queues(struct ublk_device *ub) 1326 { 1327 int nr_queues = ub->dev_info.nr_hw_queues; 1328 int i; 1329 1330 if (!ub->__queues) 1331 return; 1332 1333 for (i = 0; i < nr_queues; i++) 1334 ublk_deinit_queue(ub, i); 1335 kfree(ub->__queues); 1336 } 1337 1338 static int ublk_init_queues(struct ublk_device *ub) 1339 { 1340 int nr_queues = ub->dev_info.nr_hw_queues; 1341 int depth = ub->dev_info.queue_depth; 1342 int ubq_size = sizeof(struct ublk_queue) + depth * sizeof(struct ublk_io); 1343 int i, ret = -ENOMEM; 1344 1345 ub->queue_size = ubq_size; 1346 ub->__queues = kcalloc(nr_queues, ubq_size, GFP_KERNEL); 1347 if (!ub->__queues) 1348 return ret; 1349 1350 for (i = 0; i < nr_queues; i++) { 1351 if (ublk_init_queue(ub, i)) 1352 goto fail; 1353 } 1354 1355 init_completion(&ub->completion); 1356 return 0; 1357 1358 fail: 1359 ublk_deinit_queues(ub); 1360 return ret; 1361 } 1362 1363 static int ublk_alloc_dev_number(struct ublk_device *ub, int idx) 1364 { 1365 int i = idx; 1366 int err; 1367 1368 spin_lock(&ublk_idr_lock); 1369 /* allocate id, if @id >= 0, we're requesting that specific id */ 1370 if (i >= 0) { 1371 err = idr_alloc(&ublk_index_idr, ub, i, i + 1, GFP_NOWAIT); 1372 if (err == -ENOSPC) 1373 err = -EEXIST; 1374 } else { 1375 err = idr_alloc(&ublk_index_idr, ub, 0, 0, GFP_NOWAIT); 1376 } 1377 spin_unlock(&ublk_idr_lock); 1378 1379 if (err >= 0) 1380 ub->ub_number = err; 1381 1382 return err; 1383 } 1384 1385 static void ublk_free_dev_number(struct ublk_device *ub) 1386 { 1387 spin_lock(&ublk_idr_lock); 1388 idr_remove(&ublk_index_idr, ub->ub_number); 1389 wake_up_all(&ublk_idr_wq); 1390 spin_unlock(&ublk_idr_lock); 1391 } 1392 1393 static void ublk_cdev_rel(struct device *dev) 1394 { 1395 struct ublk_device *ub = container_of(dev, struct ublk_device, cdev_dev); 1396 1397 blk_mq_free_tag_set(&ub->tag_set); 1398 ublk_deinit_queues(ub); 1399 ublk_free_dev_number(ub); 1400 mutex_destroy(&ub->mutex); 1401 kfree(ub); 1402 } 1403 1404 static int ublk_add_chdev(struct ublk_device *ub) 1405 { 1406 struct device *dev = &ub->cdev_dev; 1407 int minor = ub->ub_number; 1408 int ret; 1409 1410 dev->parent = ublk_misc.this_device; 1411 dev->devt = MKDEV(MAJOR(ublk_chr_devt), minor); 1412 dev->class = ublk_chr_class; 1413 dev->release = ublk_cdev_rel; 1414 device_initialize(dev); 1415 1416 ret = dev_set_name(dev, "ublkc%d", minor); 1417 if (ret) 1418 goto fail; 1419 1420 cdev_init(&ub->cdev, &ublk_ch_fops); 1421 ret = cdev_device_add(&ub->cdev, dev); 1422 if (ret) 1423 goto fail; 1424 return 0; 1425 fail: 1426 put_device(dev); 1427 return ret; 1428 } 1429 1430 static void ublk_stop_work_fn(struct work_struct *work) 1431 { 1432 struct ublk_device *ub = 1433 container_of(work, struct ublk_device, stop_work); 1434 1435 ublk_stop_dev(ub); 1436 } 1437 1438 /* align max io buffer size with PAGE_SIZE */ 1439 static void ublk_align_max_io_size(struct ublk_device *ub) 1440 { 1441 unsigned int max_io_bytes = ub->dev_info.max_io_buf_bytes; 1442 1443 ub->dev_info.max_io_buf_bytes = 1444 round_down(max_io_bytes, PAGE_SIZE); 1445 } 1446 1447 static int ublk_add_tag_set(struct ublk_device *ub) 1448 { 1449 ub->tag_set.ops = &ublk_mq_ops; 1450 ub->tag_set.nr_hw_queues = ub->dev_info.nr_hw_queues; 1451 ub->tag_set.queue_depth = ub->dev_info.queue_depth; 1452 ub->tag_set.numa_node = NUMA_NO_NODE; 1453 ub->tag_set.cmd_size = sizeof(struct ublk_rq_data); 1454 ub->tag_set.flags = BLK_MQ_F_SHOULD_MERGE; 1455 ub->tag_set.driver_data = ub; 1456 return blk_mq_alloc_tag_set(&ub->tag_set); 1457 } 1458 1459 static void ublk_remove(struct ublk_device *ub) 1460 { 1461 ublk_stop_dev(ub); 1462 cancel_work_sync(&ub->stop_work); 1463 cancel_work_sync(&ub->quiesce_work); 1464 cdev_device_del(&ub->cdev, &ub->cdev_dev); 1465 put_device(&ub->cdev_dev); 1466 } 1467 1468 static struct ublk_device *ublk_get_device_from_id(int idx) 1469 { 1470 struct ublk_device *ub = NULL; 1471 1472 if (idx < 0) 1473 return NULL; 1474 1475 spin_lock(&ublk_idr_lock); 1476 ub = idr_find(&ublk_index_idr, idx); 1477 if (ub) 1478 ub = ublk_get_device(ub); 1479 spin_unlock(&ublk_idr_lock); 1480 1481 return ub; 1482 } 1483 1484 static int ublk_ctrl_start_dev(struct io_uring_cmd *cmd) 1485 { 1486 struct ublksrv_ctrl_cmd *header = (struct ublksrv_ctrl_cmd *)cmd->cmd; 1487 int ublksrv_pid = (int)header->data[0]; 1488 struct ublk_device *ub; 1489 struct gendisk *disk; 1490 int ret = -EINVAL; 1491 1492 if (ublksrv_pid <= 0) 1493 return -EINVAL; 1494 1495 ub = ublk_get_device_from_id(header->dev_id); 1496 if (!ub) 1497 return -EINVAL; 1498 1499 wait_for_completion_interruptible(&ub->completion); 1500 1501 schedule_delayed_work(&ub->monitor_work, UBLK_DAEMON_MONITOR_PERIOD); 1502 1503 mutex_lock(&ub->mutex); 1504 if (ub->dev_info.state == UBLK_S_DEV_LIVE || 1505 test_bit(UB_STATE_USED, &ub->state)) { 1506 ret = -EEXIST; 1507 goto out_unlock; 1508 } 1509 1510 disk = blk_mq_alloc_disk(&ub->tag_set, ub); 1511 if (IS_ERR(disk)) { 1512 ret = PTR_ERR(disk); 1513 goto out_unlock; 1514 } 1515 sprintf(disk->disk_name, "ublkb%d", ub->ub_number); 1516 disk->fops = &ub_fops; 1517 disk->private_data = ub; 1518 1519 ub->dev_info.ublksrv_pid = ublksrv_pid; 1520 ub->ub_disk = disk; 1521 1522 ret = ublk_apply_params(ub); 1523 if (ret) 1524 goto out_put_disk; 1525 1526 get_device(&ub->cdev_dev); 1527 ret = add_disk(disk); 1528 if (ret) { 1529 /* 1530 * Has to drop the reference since ->free_disk won't be 1531 * called in case of add_disk failure. 1532 */ 1533 ublk_put_device(ub); 1534 goto out_put_disk; 1535 } 1536 set_bit(UB_STATE_USED, &ub->state); 1537 ub->dev_info.state = UBLK_S_DEV_LIVE; 1538 out_put_disk: 1539 if (ret) 1540 put_disk(disk); 1541 out_unlock: 1542 mutex_unlock(&ub->mutex); 1543 ublk_put_device(ub); 1544 return ret; 1545 } 1546 1547 static int ublk_ctrl_get_queue_affinity(struct io_uring_cmd *cmd) 1548 { 1549 struct ublksrv_ctrl_cmd *header = (struct ublksrv_ctrl_cmd *)cmd->cmd; 1550 void __user *argp = (void __user *)(unsigned long)header->addr; 1551 struct ublk_device *ub; 1552 cpumask_var_t cpumask; 1553 unsigned long queue; 1554 unsigned int retlen; 1555 unsigned int i; 1556 int ret = -EINVAL; 1557 1558 if (header->len * BITS_PER_BYTE < nr_cpu_ids) 1559 return -EINVAL; 1560 if (header->len & (sizeof(unsigned long)-1)) 1561 return -EINVAL; 1562 if (!header->addr) 1563 return -EINVAL; 1564 1565 ub = ublk_get_device_from_id(header->dev_id); 1566 if (!ub) 1567 return -EINVAL; 1568 1569 queue = header->data[0]; 1570 if (queue >= ub->dev_info.nr_hw_queues) 1571 goto out_put_device; 1572 1573 ret = -ENOMEM; 1574 if (!zalloc_cpumask_var(&cpumask, GFP_KERNEL)) 1575 goto out_put_device; 1576 1577 for_each_possible_cpu(i) { 1578 if (ub->tag_set.map[HCTX_TYPE_DEFAULT].mq_map[i] == queue) 1579 cpumask_set_cpu(i, cpumask); 1580 } 1581 1582 ret = -EFAULT; 1583 retlen = min_t(unsigned short, header->len, cpumask_size()); 1584 if (copy_to_user(argp, cpumask, retlen)) 1585 goto out_free_cpumask; 1586 if (retlen != header->len && 1587 clear_user(argp + retlen, header->len - retlen)) 1588 goto out_free_cpumask; 1589 1590 ret = 0; 1591 out_free_cpumask: 1592 free_cpumask_var(cpumask); 1593 out_put_device: 1594 ublk_put_device(ub); 1595 return ret; 1596 } 1597 1598 static inline void ublk_dump_dev_info(struct ublksrv_ctrl_dev_info *info) 1599 { 1600 pr_devel("%s: dev id %d flags %llx\n", __func__, 1601 info->dev_id, info->flags); 1602 pr_devel("\t nr_hw_queues %d queue_depth %d\n", 1603 info->nr_hw_queues, info->queue_depth); 1604 } 1605 1606 static int ublk_ctrl_add_dev(struct io_uring_cmd *cmd) 1607 { 1608 struct ublksrv_ctrl_cmd *header = (struct ublksrv_ctrl_cmd *)cmd->cmd; 1609 void __user *argp = (void __user *)(unsigned long)header->addr; 1610 struct ublksrv_ctrl_dev_info info; 1611 struct ublk_device *ub; 1612 int ret = -EINVAL; 1613 1614 if (header->len < sizeof(info) || !header->addr) 1615 return -EINVAL; 1616 if (header->queue_id != (u16)-1) { 1617 pr_warn("%s: queue_id is wrong %x\n", 1618 __func__, header->queue_id); 1619 return -EINVAL; 1620 } 1621 if (copy_from_user(&info, argp, sizeof(info))) 1622 return -EFAULT; 1623 ublk_dump_dev_info(&info); 1624 if (header->dev_id != info.dev_id) { 1625 pr_warn("%s: dev id not match %u %u\n", 1626 __func__, header->dev_id, info.dev_id); 1627 return -EINVAL; 1628 } 1629 1630 ret = mutex_lock_killable(&ublk_ctl_mutex); 1631 if (ret) 1632 return ret; 1633 1634 ret = -ENOMEM; 1635 ub = kzalloc(sizeof(*ub), GFP_KERNEL); 1636 if (!ub) 1637 goto out_unlock; 1638 mutex_init(&ub->mutex); 1639 spin_lock_init(&ub->mm_lock); 1640 INIT_WORK(&ub->quiesce_work, ublk_quiesce_work_fn); 1641 INIT_WORK(&ub->stop_work, ublk_stop_work_fn); 1642 INIT_DELAYED_WORK(&ub->monitor_work, ublk_daemon_monitor_work); 1643 1644 ret = ublk_alloc_dev_number(ub, header->dev_id); 1645 if (ret < 0) 1646 goto out_free_ub; 1647 1648 memcpy(&ub->dev_info, &info, sizeof(info)); 1649 1650 /* update device id */ 1651 ub->dev_info.dev_id = ub->ub_number; 1652 1653 /* 1654 * 64bit flags will be copied back to userspace as feature 1655 * negotiation result, so have to clear flags which driver 1656 * doesn't support yet, then userspace can get correct flags 1657 * (features) to handle. 1658 */ 1659 ub->dev_info.flags &= UBLK_F_ALL; 1660 1661 /* We are not ready to support zero copy */ 1662 ub->dev_info.flags &= ~UBLK_F_SUPPORT_ZERO_COPY; 1663 1664 ub->dev_info.nr_hw_queues = min_t(unsigned int, 1665 ub->dev_info.nr_hw_queues, nr_cpu_ids); 1666 ublk_align_max_io_size(ub); 1667 1668 ret = ublk_init_queues(ub); 1669 if (ret) 1670 goto out_free_dev_number; 1671 1672 ret = ublk_add_tag_set(ub); 1673 if (ret) 1674 goto out_deinit_queues; 1675 1676 ret = -EFAULT; 1677 if (copy_to_user(argp, &ub->dev_info, sizeof(info))) 1678 goto out_free_tag_set; 1679 1680 /* 1681 * Add the char dev so that ublksrv daemon can be setup. 1682 * ublk_add_chdev() will cleanup everything if it fails. 1683 */ 1684 ret = ublk_add_chdev(ub); 1685 goto out_unlock; 1686 1687 out_free_tag_set: 1688 blk_mq_free_tag_set(&ub->tag_set); 1689 out_deinit_queues: 1690 ublk_deinit_queues(ub); 1691 out_free_dev_number: 1692 ublk_free_dev_number(ub); 1693 out_free_ub: 1694 mutex_destroy(&ub->mutex); 1695 kfree(ub); 1696 out_unlock: 1697 mutex_unlock(&ublk_ctl_mutex); 1698 return ret; 1699 } 1700 1701 static inline bool ublk_idr_freed(int id) 1702 { 1703 void *ptr; 1704 1705 spin_lock(&ublk_idr_lock); 1706 ptr = idr_find(&ublk_index_idr, id); 1707 spin_unlock(&ublk_idr_lock); 1708 1709 return ptr == NULL; 1710 } 1711 1712 static int ublk_ctrl_del_dev(int idx) 1713 { 1714 struct ublk_device *ub; 1715 int ret; 1716 1717 ret = mutex_lock_killable(&ublk_ctl_mutex); 1718 if (ret) 1719 return ret; 1720 1721 ub = ublk_get_device_from_id(idx); 1722 if (ub) { 1723 ublk_remove(ub); 1724 ublk_put_device(ub); 1725 ret = 0; 1726 } else { 1727 ret = -ENODEV; 1728 } 1729 1730 /* 1731 * Wait until the idr is removed, then it can be reused after 1732 * DEL_DEV command is returned. 1733 */ 1734 if (!ret) 1735 wait_event(ublk_idr_wq, ublk_idr_freed(idx)); 1736 mutex_unlock(&ublk_ctl_mutex); 1737 1738 return ret; 1739 } 1740 1741 static inline void ublk_ctrl_cmd_dump(struct io_uring_cmd *cmd) 1742 { 1743 struct ublksrv_ctrl_cmd *header = (struct ublksrv_ctrl_cmd *)cmd->cmd; 1744 1745 pr_devel("%s: cmd_op %x, dev id %d qid %d data %llx buf %llx len %u\n", 1746 __func__, cmd->cmd_op, header->dev_id, header->queue_id, 1747 header->data[0], header->addr, header->len); 1748 } 1749 1750 static int ublk_ctrl_stop_dev(struct io_uring_cmd *cmd) 1751 { 1752 struct ublksrv_ctrl_cmd *header = (struct ublksrv_ctrl_cmd *)cmd->cmd; 1753 struct ublk_device *ub; 1754 1755 ub = ublk_get_device_from_id(header->dev_id); 1756 if (!ub) 1757 return -EINVAL; 1758 1759 ublk_stop_dev(ub); 1760 cancel_work_sync(&ub->stop_work); 1761 cancel_work_sync(&ub->quiesce_work); 1762 1763 ublk_put_device(ub); 1764 return 0; 1765 } 1766 1767 static int ublk_ctrl_get_dev_info(struct io_uring_cmd *cmd) 1768 { 1769 struct ublksrv_ctrl_cmd *header = (struct ublksrv_ctrl_cmd *)cmd->cmd; 1770 void __user *argp = (void __user *)(unsigned long)header->addr; 1771 struct ublk_device *ub; 1772 int ret = 0; 1773 1774 if (header->len < sizeof(struct ublksrv_ctrl_dev_info) || !header->addr) 1775 return -EINVAL; 1776 1777 ub = ublk_get_device_from_id(header->dev_id); 1778 if (!ub) 1779 return -EINVAL; 1780 1781 if (copy_to_user(argp, &ub->dev_info, sizeof(ub->dev_info))) 1782 ret = -EFAULT; 1783 ublk_put_device(ub); 1784 1785 return ret; 1786 } 1787 1788 static int ublk_ctrl_get_params(struct io_uring_cmd *cmd) 1789 { 1790 struct ublksrv_ctrl_cmd *header = (struct ublksrv_ctrl_cmd *)cmd->cmd; 1791 void __user *argp = (void __user *)(unsigned long)header->addr; 1792 struct ublk_params_header ph; 1793 struct ublk_device *ub; 1794 int ret; 1795 1796 if (header->len <= sizeof(ph) || !header->addr) 1797 return -EINVAL; 1798 1799 if (copy_from_user(&ph, argp, sizeof(ph))) 1800 return -EFAULT; 1801 1802 if (ph.len > header->len || !ph.len) 1803 return -EINVAL; 1804 1805 if (ph.len > sizeof(struct ublk_params)) 1806 ph.len = sizeof(struct ublk_params); 1807 1808 ub = ublk_get_device_from_id(header->dev_id); 1809 if (!ub) 1810 return -EINVAL; 1811 1812 mutex_lock(&ub->mutex); 1813 if (copy_to_user(argp, &ub->params, ph.len)) 1814 ret = -EFAULT; 1815 else 1816 ret = 0; 1817 mutex_unlock(&ub->mutex); 1818 1819 ublk_put_device(ub); 1820 return ret; 1821 } 1822 1823 static int ublk_ctrl_set_params(struct io_uring_cmd *cmd) 1824 { 1825 struct ublksrv_ctrl_cmd *header = (struct ublksrv_ctrl_cmd *)cmd->cmd; 1826 void __user *argp = (void __user *)(unsigned long)header->addr; 1827 struct ublk_params_header ph; 1828 struct ublk_device *ub; 1829 int ret = -EFAULT; 1830 1831 if (header->len <= sizeof(ph) || !header->addr) 1832 return -EINVAL; 1833 1834 if (copy_from_user(&ph, argp, sizeof(ph))) 1835 return -EFAULT; 1836 1837 if (ph.len > header->len || !ph.len || !ph.types) 1838 return -EINVAL; 1839 1840 if (ph.len > sizeof(struct ublk_params)) 1841 ph.len = sizeof(struct ublk_params); 1842 1843 ub = ublk_get_device_from_id(header->dev_id); 1844 if (!ub) 1845 return -EINVAL; 1846 1847 /* parameters can only be changed when device isn't live */ 1848 mutex_lock(&ub->mutex); 1849 if (ub->dev_info.state == UBLK_S_DEV_LIVE) { 1850 ret = -EACCES; 1851 } else if (copy_from_user(&ub->params, argp, ph.len)) { 1852 ret = -EFAULT; 1853 } else { 1854 /* clear all we don't support yet */ 1855 ub->params.types &= UBLK_PARAM_TYPE_ALL; 1856 ret = ublk_validate_params(ub); 1857 } 1858 mutex_unlock(&ub->mutex); 1859 ublk_put_device(ub); 1860 1861 return ret; 1862 } 1863 1864 static void ublk_queue_reinit(struct ublk_device *ub, struct ublk_queue *ubq) 1865 { 1866 int i; 1867 1868 WARN_ON_ONCE(!(ubq->ubq_daemon && ubq_daemon_is_dying(ubq))); 1869 /* All old ioucmds have to be completed */ 1870 WARN_ON_ONCE(ubq->nr_io_ready); 1871 /* old daemon is PF_EXITING, put it now */ 1872 put_task_struct(ubq->ubq_daemon); 1873 /* We have to reset it to NULL, otherwise ub won't accept new FETCH_REQ */ 1874 ubq->ubq_daemon = NULL; 1875 1876 for (i = 0; i < ubq->q_depth; i++) { 1877 struct ublk_io *io = &ubq->ios[i]; 1878 1879 /* forget everything now and be ready for new FETCH_REQ */ 1880 io->flags = 0; 1881 io->cmd = NULL; 1882 io->addr = 0; 1883 } 1884 } 1885 1886 static int ublk_ctrl_start_recovery(struct io_uring_cmd *cmd) 1887 { 1888 struct ublksrv_ctrl_cmd *header = (struct ublksrv_ctrl_cmd *)cmd->cmd; 1889 struct ublk_device *ub; 1890 int ret = -EINVAL; 1891 int i; 1892 1893 ub = ublk_get_device_from_id(header->dev_id); 1894 if (!ub) 1895 return ret; 1896 1897 mutex_lock(&ub->mutex); 1898 if (!ublk_can_use_recovery(ub)) 1899 goto out_unlock; 1900 /* 1901 * START_RECOVERY is only allowd after: 1902 * 1903 * (1) UB_STATE_OPEN is not set, which means the dying process is exited 1904 * and related io_uring ctx is freed so file struct of /dev/ublkcX is 1905 * released. 1906 * 1907 * (2) UBLK_S_DEV_QUIESCED is set, which means the quiesce_work: 1908 * (a)has quiesced request queue 1909 * (b)has requeued every inflight rqs whose io_flags is ACTIVE 1910 * (c)has requeued/aborted every inflight rqs whose io_flags is NOT ACTIVE 1911 * (d)has completed/camceled all ioucmds owned by ther dying process 1912 */ 1913 if (test_bit(UB_STATE_OPEN, &ub->state) || 1914 ub->dev_info.state != UBLK_S_DEV_QUIESCED) { 1915 ret = -EBUSY; 1916 goto out_unlock; 1917 } 1918 pr_devel("%s: start recovery for dev id %d.\n", __func__, header->dev_id); 1919 for (i = 0; i < ub->dev_info.nr_hw_queues; i++) 1920 ublk_queue_reinit(ub, ublk_get_queue(ub, i)); 1921 /* set to NULL, otherwise new ubq_daemon cannot mmap the io_cmd_buf */ 1922 ub->mm = NULL; 1923 ub->nr_queues_ready = 0; 1924 init_completion(&ub->completion); 1925 ret = 0; 1926 out_unlock: 1927 mutex_unlock(&ub->mutex); 1928 ublk_put_device(ub); 1929 return ret; 1930 } 1931 1932 static int ublk_ctrl_end_recovery(struct io_uring_cmd *cmd) 1933 { 1934 struct ublksrv_ctrl_cmd *header = (struct ublksrv_ctrl_cmd *)cmd->cmd; 1935 int ublksrv_pid = (int)header->data[0]; 1936 struct ublk_device *ub; 1937 int ret = -EINVAL; 1938 1939 ub = ublk_get_device_from_id(header->dev_id); 1940 if (!ub) 1941 return ret; 1942 1943 pr_devel("%s: Waiting for new ubq_daemons(nr: %d) are ready, dev id %d...\n", 1944 __func__, ub->dev_info.nr_hw_queues, header->dev_id); 1945 /* wait until new ubq_daemon sending all FETCH_REQ */ 1946 wait_for_completion_interruptible(&ub->completion); 1947 pr_devel("%s: All new ubq_daemons(nr: %d) are ready, dev id %d\n", 1948 __func__, ub->dev_info.nr_hw_queues, header->dev_id); 1949 1950 mutex_lock(&ub->mutex); 1951 if (!ublk_can_use_recovery(ub)) 1952 goto out_unlock; 1953 1954 if (ub->dev_info.state != UBLK_S_DEV_QUIESCED) { 1955 ret = -EBUSY; 1956 goto out_unlock; 1957 } 1958 ub->dev_info.ublksrv_pid = ublksrv_pid; 1959 pr_devel("%s: new ublksrv_pid %d, dev id %d\n", 1960 __func__, ublksrv_pid, header->dev_id); 1961 blk_mq_unquiesce_queue(ub->ub_disk->queue); 1962 pr_devel("%s: queue unquiesced, dev id %d.\n", 1963 __func__, header->dev_id); 1964 blk_mq_kick_requeue_list(ub->ub_disk->queue); 1965 ub->dev_info.state = UBLK_S_DEV_LIVE; 1966 schedule_delayed_work(&ub->monitor_work, UBLK_DAEMON_MONITOR_PERIOD); 1967 ret = 0; 1968 out_unlock: 1969 mutex_unlock(&ub->mutex); 1970 ublk_put_device(ub); 1971 return ret; 1972 } 1973 1974 static int ublk_ctrl_uring_cmd(struct io_uring_cmd *cmd, 1975 unsigned int issue_flags) 1976 { 1977 struct ublksrv_ctrl_cmd *header = (struct ublksrv_ctrl_cmd *)cmd->cmd; 1978 int ret = -EINVAL; 1979 1980 ublk_ctrl_cmd_dump(cmd); 1981 1982 if (!(issue_flags & IO_URING_F_SQE128)) 1983 goto out; 1984 1985 ret = -EPERM; 1986 if (!capable(CAP_SYS_ADMIN)) 1987 goto out; 1988 1989 ret = -ENODEV; 1990 switch (cmd->cmd_op) { 1991 case UBLK_CMD_START_DEV: 1992 ret = ublk_ctrl_start_dev(cmd); 1993 break; 1994 case UBLK_CMD_STOP_DEV: 1995 ret = ublk_ctrl_stop_dev(cmd); 1996 break; 1997 case UBLK_CMD_GET_DEV_INFO: 1998 ret = ublk_ctrl_get_dev_info(cmd); 1999 break; 2000 case UBLK_CMD_ADD_DEV: 2001 ret = ublk_ctrl_add_dev(cmd); 2002 break; 2003 case UBLK_CMD_DEL_DEV: 2004 ret = ublk_ctrl_del_dev(header->dev_id); 2005 break; 2006 case UBLK_CMD_GET_QUEUE_AFFINITY: 2007 ret = ublk_ctrl_get_queue_affinity(cmd); 2008 break; 2009 case UBLK_CMD_GET_PARAMS: 2010 ret = ublk_ctrl_get_params(cmd); 2011 break; 2012 case UBLK_CMD_SET_PARAMS: 2013 ret = ublk_ctrl_set_params(cmd); 2014 break; 2015 case UBLK_CMD_START_USER_RECOVERY: 2016 ret = ublk_ctrl_start_recovery(cmd); 2017 break; 2018 case UBLK_CMD_END_USER_RECOVERY: 2019 ret = ublk_ctrl_end_recovery(cmd); 2020 break; 2021 default: 2022 break; 2023 } 2024 out: 2025 io_uring_cmd_done(cmd, ret, 0); 2026 pr_devel("%s: cmd done ret %d cmd_op %x, dev id %d qid %d\n", 2027 __func__, ret, cmd->cmd_op, header->dev_id, header->queue_id); 2028 return -EIOCBQUEUED; 2029 } 2030 2031 static const struct file_operations ublk_ctl_fops = { 2032 .open = nonseekable_open, 2033 .uring_cmd = ublk_ctrl_uring_cmd, 2034 .owner = THIS_MODULE, 2035 .llseek = noop_llseek, 2036 }; 2037 2038 static struct miscdevice ublk_misc = { 2039 .minor = MISC_DYNAMIC_MINOR, 2040 .name = "ublk-control", 2041 .fops = &ublk_ctl_fops, 2042 }; 2043 2044 static int __init ublk_init(void) 2045 { 2046 int ret; 2047 2048 init_waitqueue_head(&ublk_idr_wq); 2049 2050 ret = misc_register(&ublk_misc); 2051 if (ret) 2052 return ret; 2053 2054 ret = alloc_chrdev_region(&ublk_chr_devt, 0, UBLK_MINORS, "ublk-char"); 2055 if (ret) 2056 goto unregister_mis; 2057 2058 ublk_chr_class = class_create(THIS_MODULE, "ublk-char"); 2059 if (IS_ERR(ublk_chr_class)) { 2060 ret = PTR_ERR(ublk_chr_class); 2061 goto free_chrdev_region; 2062 } 2063 return 0; 2064 2065 free_chrdev_region: 2066 unregister_chrdev_region(ublk_chr_devt, UBLK_MINORS); 2067 unregister_mis: 2068 misc_deregister(&ublk_misc); 2069 return ret; 2070 } 2071 2072 static void __exit ublk_exit(void) 2073 { 2074 struct ublk_device *ub; 2075 int id; 2076 2077 class_destroy(ublk_chr_class); 2078 2079 misc_deregister(&ublk_misc); 2080 2081 idr_for_each_entry(&ublk_index_idr, ub, id) 2082 ublk_remove(ub); 2083 2084 idr_destroy(&ublk_index_idr); 2085 unregister_chrdev_region(ublk_chr_devt, UBLK_MINORS); 2086 } 2087 2088 module_init(ublk_init); 2089 module_exit(ublk_exit); 2090 2091 MODULE_AUTHOR("Ming Lei <ming.lei@redhat.com>"); 2092 MODULE_LICENSE("GPL"); 2093