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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578 579 580 581 582 583 584 585 586 587 588 589 590 591 592 593 594 595 596 597 598 599 600 601 602 603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740 741 742 743 744 745 746 747 748 749 750 751 752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 770 771 772 773 774 775 776 777 778 779 780 781 782 783 784 785 786 787 788 789 790 791 792 793 794 795 796 797 798 799 800 801 802 803 804 805 806 807 808 809 810 811 812 813 814 815 816 817 818 819 820 821 822 823 824 825 826 827 828 829 830 831 832 833 834 835 836 837 838 839 840 841 842 843 844 845 846 847 848 849 850 851 852 853 854 855 856 857 858 859 860 861 862 863 864 865 866 867 868 869 870 871 872 873 874 875 876 877 878 879 880 881 882 883 884 885 886 887 888 889 890 891 892 893 894 895 896 897 898 899 900 901 902 903 904 905 906 907 908 909 910 911 912 913 914 915 916 917 918 919 920 921 922 923 924 925 926 927 928 929 930 931 932 933 934 935 936 937 938 939 940 941 942 943 944 945 946 947 948 949 950 951 952 953 954 955 956 957 958 959 960 961 962 963 964 965 966 967 968 969 970 971 972 973 974 975 976 977 978 979 980 981 982 983 984 985 986 987 988 989 990 991 992 993 994 995 996 997 998 999 1000 1001 1002 1003 1004 1005 1006 1007 1008 1009 1010 1011 1012 1013 1014 1015 1016 1017 1018 1019 1020 1021 1022 1023 1024 1025 1026 1027 1028 1029 1030 1031 1032 1033 1034 1035 1036 1037 1038 1039 1040 1041 1042 1043 1044 1045 1046 1047 1048 1049 1050 1051 1052 1053 1054 1055 1056 1057 1058 1059 1060 1061 1062 1063 1064 1065 1066 1067 1068 1069 1070 | // SPDX-License-Identifier: GPL-2.0 #include <linux/kernel.h> #include <linux/errno.h> #include <linux/fs.h> #include <linux/file.h> #include <linux/blk-mq.h> #include <linux/mm.h> #include <linux/slab.h> #include <linux/fsnotify.h> #include <linux/poll.h> #include <linux/nospec.h> #include <linux/compat.h> #include <linux/io_uring.h> #include <uapi/linux/io_uring.h> #include "io_uring.h" #include "opdef.h" #include "kbuf.h" #include "rsrc.h" #include "rw.h" struct io_rw { /* NOTE: kiocb has the file as the first member, so don't do it here */ struct kiocb kiocb; u64 addr; u32 len; rwf_t flags; }; static inline bool io_file_supports_nowait(struct io_kiocb *req) { return req->flags & REQ_F_SUPPORT_NOWAIT; } #ifdef CONFIG_COMPAT static int io_iov_compat_buffer_select_prep(struct io_rw *rw) { struct compat_iovec __user *uiov; compat_ssize_t clen; uiov = u64_to_user_ptr(rw->addr); if (!access_ok(uiov, sizeof(*uiov))) return -EFAULT; if (__get_user(clen, &uiov->iov_len)) return -EFAULT; if (clen < 0) return -EINVAL; rw->len = clen; return 0; } #endif static int io_iov_buffer_select_prep(struct io_kiocb *req) { struct iovec __user *uiov; struct iovec iov; struct io_rw *rw = io_kiocb_to_cmd(req, struct io_rw); if (rw->len != 1) return -EINVAL; #ifdef CONFIG_COMPAT if (req->ctx->compat) return io_iov_compat_buffer_select_prep(rw); #endif uiov = u64_to_user_ptr(rw->addr); if (copy_from_user(&iov, uiov, sizeof(*uiov))) return -EFAULT; rw->len = iov.iov_len; return 0; } int io_prep_rw(struct io_kiocb *req, const struct io_uring_sqe *sqe) { struct io_rw *rw = io_kiocb_to_cmd(req, struct io_rw); unsigned ioprio; int ret; rw->kiocb.ki_pos = READ_ONCE(sqe->off); /* used for fixed read/write too - just read unconditionally */ req->buf_index = READ_ONCE(sqe->buf_index); if (req->opcode == IORING_OP_READ_FIXED || req->opcode == IORING_OP_WRITE_FIXED) { struct io_ring_ctx *ctx = req->ctx; u16 index; if (unlikely(req->buf_index >= ctx->nr_user_bufs)) return -EFAULT; index = array_index_nospec(req->buf_index, ctx->nr_user_bufs); req->imu = ctx->user_bufs[index]; io_req_set_rsrc_node(req, ctx, 0); } ioprio = READ_ONCE(sqe->ioprio); if (ioprio) { ret = ioprio_check_cap(ioprio); if (ret) return ret; rw->kiocb.ki_ioprio = ioprio; } else { rw->kiocb.ki_ioprio = get_current_ioprio(); } rw->kiocb.dio_complete = NULL; rw->addr = READ_ONCE(sqe->addr); rw->len = READ_ONCE(sqe->len); rw->flags = READ_ONCE(sqe->rw_flags); /* Have to do this validation here, as this is in io_read() rw->len might * have chanaged due to buffer selection */ if (req->opcode == IORING_OP_READV && req->flags & REQ_F_BUFFER_SELECT) { ret = io_iov_buffer_select_prep(req); if (ret) return ret; } return 0; } void io_readv_writev_cleanup(struct io_kiocb *req) { struct io_async_rw *io = req->async_data; kfree(io->free_iovec); } static inline void io_rw_done(struct kiocb *kiocb, ssize_t ret) { switch (ret) { case -EIOCBQUEUED: break; case -ERESTARTSYS: case -ERESTARTNOINTR: case -ERESTARTNOHAND: case -ERESTART_RESTARTBLOCK: /* * We can't just restart the syscall, since previously * submitted sqes may already be in progress. Just fail this * IO with EINTR. */ ret = -EINTR; fallthrough; default: kiocb->ki_complete(kiocb, ret); } } static inline loff_t *io_kiocb_update_pos(struct io_kiocb *req) { struct io_rw *rw = io_kiocb_to_cmd(req, struct io_rw); if (rw->kiocb.ki_pos != -1) return &rw->kiocb.ki_pos; if (!(req->file->f_mode & FMODE_STREAM)) { req->flags |= REQ_F_CUR_POS; rw->kiocb.ki_pos = req->file->f_pos; return &rw->kiocb.ki_pos; } rw->kiocb.ki_pos = 0; return NULL; } static void io_req_task_queue_reissue(struct io_kiocb *req) { req->io_task_work.func = io_queue_iowq; io_req_task_work_add(req); } #ifdef CONFIG_BLOCK static bool io_resubmit_prep(struct io_kiocb *req) { struct io_async_rw *io = req->async_data; if (!req_has_async_data(req)) return !io_req_prep_async(req); iov_iter_restore(&io->s.iter, &io->s.iter_state); return true; } static bool io_rw_should_reissue(struct io_kiocb *req) { umode_t mode = file_inode(req->file)->i_mode; struct io_ring_ctx *ctx = req->ctx; if (!S_ISBLK(mode) && !S_ISREG(mode)) return false; if ((req->flags & REQ_F_NOWAIT) || (io_wq_current_is_worker() && !(ctx->flags & IORING_SETUP_IOPOLL))) return false; /* * If ref is dying, we might be running poll reap from the exit work. * Don't attempt to reissue from that path, just let it fail with * -EAGAIN. */ if (percpu_ref_is_dying(&ctx->refs)) return false; /* * Play it safe and assume not safe to re-import and reissue if we're * not in the original thread group (or in task context). */ if (!same_thread_group(req->task, current) || !in_task()) return false; return true; } #else static bool io_resubmit_prep(struct io_kiocb *req) { return false; } static bool io_rw_should_reissue(struct io_kiocb *req) { return false; } #endif static void io_req_end_write(struct io_kiocb *req) { if (req->flags & REQ_F_ISREG) { struct io_rw *rw = io_kiocb_to_cmd(req, struct io_rw); kiocb_end_write(&rw->kiocb); } } /* * Trigger the notifications after having done some IO, and finish the write * accounting, if any. */ static void io_req_io_end(struct io_kiocb *req) { struct io_rw *rw = io_kiocb_to_cmd(req, struct io_rw); if (rw->kiocb.ki_flags & IOCB_WRITE) { io_req_end_write(req); fsnotify_modify(req->file); } else { fsnotify_access(req->file); } } static bool __io_complete_rw_common(struct io_kiocb *req, long res) { if (unlikely(res != req->cqe.res)) { if ((res == -EAGAIN || res == -EOPNOTSUPP) && io_rw_should_reissue(req)) { /* * Reissue will start accounting again, finish the * current cycle. */ io_req_io_end(req); req->flags |= REQ_F_REISSUE | REQ_F_PARTIAL_IO; return true; } req_set_fail(req); req->cqe.res = res; } return false; } static inline int io_fixup_rw_res(struct io_kiocb *req, long res) { struct io_async_rw *io = req->async_data; /* add previously done IO, if any */ if (req_has_async_data(req) && io->bytes_done > 0) { if (res < 0) res = io->bytes_done; else res += io->bytes_done; } return res; } void io_req_rw_complete(struct io_kiocb *req, struct io_tw_state *ts) { struct io_rw *rw = io_kiocb_to_cmd(req, struct io_rw); struct kiocb *kiocb = &rw->kiocb; if ((kiocb->ki_flags & IOCB_DIO_CALLER_COMP) && kiocb->dio_complete) { long res = kiocb->dio_complete(rw->kiocb.private); io_req_set_res(req, io_fixup_rw_res(req, res), 0); } io_req_io_end(req); if (req->flags & (REQ_F_BUFFER_SELECTED|REQ_F_BUFFER_RING)) { unsigned issue_flags = ts->locked ? 0 : IO_URING_F_UNLOCKED; req->cqe.flags |= io_put_kbuf(req, issue_flags); } io_req_task_complete(req, ts); } static void io_complete_rw(struct kiocb *kiocb, long res) { struct io_rw *rw = container_of(kiocb, struct io_rw, kiocb); struct io_kiocb *req = cmd_to_io_kiocb(rw); if (!kiocb->dio_complete || !(kiocb->ki_flags & IOCB_DIO_CALLER_COMP)) { if (__io_complete_rw_common(req, res)) return; io_req_set_res(req, io_fixup_rw_res(req, res), 0); } req->io_task_work.func = io_req_rw_complete; __io_req_task_work_add(req, IOU_F_TWQ_LAZY_WAKE); } static void io_complete_rw_iopoll(struct kiocb *kiocb, long res) { struct io_rw *rw = container_of(kiocb, struct io_rw, kiocb); struct io_kiocb *req = cmd_to_io_kiocb(rw); if (kiocb->ki_flags & IOCB_WRITE) io_req_end_write(req); if (unlikely(res != req->cqe.res)) { if (res == -EAGAIN && io_rw_should_reissue(req)) { req->flags |= REQ_F_REISSUE | REQ_F_PARTIAL_IO; return; } req->cqe.res = res; } /* order with io_iopoll_complete() checking ->iopoll_completed */ smp_store_release(&req->iopoll_completed, 1); } static int kiocb_done(struct io_kiocb *req, ssize_t ret, unsigned int issue_flags) { struct io_rw *rw = io_kiocb_to_cmd(req, struct io_rw); unsigned final_ret = io_fixup_rw_res(req, ret); if (ret >= 0 && req->flags & REQ_F_CUR_POS) req->file->f_pos = rw->kiocb.ki_pos; if (ret >= 0 && (rw->kiocb.ki_complete == io_complete_rw)) { if (!__io_complete_rw_common(req, ret)) { /* * Safe to call io_end from here as we're inline * from the submission path. */ io_req_io_end(req); io_req_set_res(req, final_ret, io_put_kbuf(req, issue_flags)); return IOU_OK; } } else { io_rw_done(&rw->kiocb, ret); } if (req->flags & REQ_F_REISSUE) { req->flags &= ~REQ_F_REISSUE; if (io_resubmit_prep(req)) io_req_task_queue_reissue(req); else io_req_task_queue_fail(req, final_ret); } return IOU_ISSUE_SKIP_COMPLETE; } static struct iovec *__io_import_iovec(int ddir, struct io_kiocb *req, struct io_rw_state *s, unsigned int issue_flags) { struct io_rw *rw = io_kiocb_to_cmd(req, struct io_rw); struct iov_iter *iter = &s->iter; u8 opcode = req->opcode; struct iovec *iovec; void __user *buf; size_t sqe_len; ssize_t ret; if (opcode == IORING_OP_READ_FIXED || opcode == IORING_OP_WRITE_FIXED) { ret = io_import_fixed(ddir, iter, req->imu, rw->addr, rw->len); if (ret) return ERR_PTR(ret); return NULL; } buf = u64_to_user_ptr(rw->addr); sqe_len = rw->len; if (opcode == IORING_OP_READ || opcode == IORING_OP_WRITE || (req->flags & REQ_F_BUFFER_SELECT)) { if (io_do_buffer_select(req)) { buf = io_buffer_select(req, &sqe_len, issue_flags); if (!buf) return ERR_PTR(-ENOBUFS); rw->addr = (unsigned long) buf; rw->len = sqe_len; } ret = import_ubuf(ddir, buf, sqe_len, iter); if (ret) return ERR_PTR(ret); return NULL; } iovec = s->fast_iov; ret = __import_iovec(ddir, buf, sqe_len, UIO_FASTIOV, &iovec, iter, req->ctx->compat); if (unlikely(ret < 0)) return ERR_PTR(ret); return iovec; } static inline int io_import_iovec(int rw, struct io_kiocb *req, struct iovec **iovec, struct io_rw_state *s, unsigned int issue_flags) { *iovec = __io_import_iovec(rw, req, s, issue_flags); if (IS_ERR(*iovec)) return PTR_ERR(*iovec); iov_iter_save_state(&s->iter, &s->iter_state); return 0; } static inline loff_t *io_kiocb_ppos(struct kiocb *kiocb) { return (kiocb->ki_filp->f_mode & FMODE_STREAM) ? NULL : &kiocb->ki_pos; } /* * For files that don't have ->read_iter() and ->write_iter(), handle them * by looping over ->read() or ->write() manually. */ static ssize_t loop_rw_iter(int ddir, struct io_rw *rw, struct iov_iter *iter) { struct kiocb *kiocb = &rw->kiocb; struct file *file = kiocb->ki_filp; ssize_t ret = 0; loff_t *ppos; /* * Don't support polled IO through this interface, and we can't * support non-blocking either. For the latter, this just causes * the kiocb to be handled from an async context. */ if (kiocb->ki_flags & IOCB_HIPRI) return -EOPNOTSUPP; if ((kiocb->ki_flags & IOCB_NOWAIT) && !(kiocb->ki_filp->f_flags & O_NONBLOCK)) return -EAGAIN; ppos = io_kiocb_ppos(kiocb); while (iov_iter_count(iter)) { void __user *addr; size_t len; ssize_t nr; if (iter_is_ubuf(iter)) { addr = iter->ubuf + iter->iov_offset; len = iov_iter_count(iter); } else if (!iov_iter_is_bvec(iter)) { addr = iter_iov_addr(iter); len = iter_iov_len(iter); } else { addr = u64_to_user_ptr(rw->addr); len = rw->len; } if (ddir == READ) nr = file->f_op->read(file, addr, len, ppos); else nr = file->f_op->write(file, addr, len, ppos); if (nr < 0) { if (!ret) ret = nr; break; } ret += nr; if (!iov_iter_is_bvec(iter)) { iov_iter_advance(iter, nr); } else { rw->addr += nr; rw->len -= nr; if (!rw->len) break; } if (nr != len) break; } return ret; } static void io_req_map_rw(struct io_kiocb *req, const struct iovec *iovec, const struct iovec *fast_iov, struct iov_iter *iter) { struct io_async_rw *io = req->async_data; memcpy(&io->s.iter, iter, sizeof(*iter)); io->free_iovec = iovec; io->bytes_done = 0; /* can only be fixed buffers, no need to do anything */ if (iov_iter_is_bvec(iter) || iter_is_ubuf(iter)) return; if (!iovec) { unsigned iov_off = 0; io->s.iter.__iov = io->s.fast_iov; if (iter->__iov != fast_iov) { iov_off = iter_iov(iter) - fast_iov; io->s.iter.__iov += iov_off; } if (io->s.fast_iov != fast_iov) memcpy(io->s.fast_iov + iov_off, fast_iov + iov_off, sizeof(struct iovec) * iter->nr_segs); } else { req->flags |= REQ_F_NEED_CLEANUP; } } static int io_setup_async_rw(struct io_kiocb *req, const struct iovec *iovec, struct io_rw_state *s, bool force) { if (!force && !io_cold_defs[req->opcode].prep_async) return 0; if (!req_has_async_data(req)) { struct io_async_rw *iorw; if (io_alloc_async_data(req)) { kfree(iovec); return -ENOMEM; } io_req_map_rw(req, iovec, s->fast_iov, &s->iter); iorw = req->async_data; /* we've copied and mapped the iter, ensure state is saved */ iov_iter_save_state(&iorw->s.iter, &iorw->s.iter_state); } return 0; } static inline int io_rw_prep_async(struct io_kiocb *req, int rw) { struct io_async_rw *iorw = req->async_data; struct iovec *iov; int ret; iorw->bytes_done = 0; iorw->free_iovec = NULL; /* submission path, ->uring_lock should already be taken */ ret = io_import_iovec(rw, req, &iov, &iorw->s, 0); if (unlikely(ret < 0)) return ret; if (iov) { iorw->free_iovec = iov; req->flags |= REQ_F_NEED_CLEANUP; } return 0; } int io_readv_prep_async(struct io_kiocb *req) { return io_rw_prep_async(req, ITER_DEST); } int io_writev_prep_async(struct io_kiocb *req) { return io_rw_prep_async(req, ITER_SOURCE); } /* * This is our waitqueue callback handler, registered through __folio_lock_async() * when we initially tried to do the IO with the iocb armed our waitqueue. * This gets called when the page is unlocked, and we generally expect that to * happen when the page IO is completed and the page is now uptodate. This will * queue a task_work based retry of the operation, attempting to copy the data * again. If the latter fails because the page was NOT uptodate, then we will * do a thread based blocking retry of the operation. That's the unexpected * slow path. */ static int io_async_buf_func(struct wait_queue_entry *wait, unsigned mode, int sync, void *arg) { struct wait_page_queue *wpq; struct io_kiocb *req = wait->private; struct io_rw *rw = io_kiocb_to_cmd(req, struct io_rw); struct wait_page_key *key = arg; wpq = container_of(wait, struct wait_page_queue, wait); if (!wake_page_match(wpq, key)) return 0; rw->kiocb.ki_flags &= ~IOCB_WAITQ; list_del_init(&wait->entry); io_req_task_queue(req); return 1; } /* * This controls whether a given IO request should be armed for async page * based retry. If we return false here, the request is handed to the async * worker threads for retry. If we're doing buffered reads on a regular file, * we prepare a private wait_page_queue entry and retry the operation. This * will either succeed because the page is now uptodate and unlocked, or it * will register a callback when the page is unlocked at IO completion. Through * that callback, io_uring uses task_work to setup a retry of the operation. * That retry will attempt the buffered read again. The retry will generally * succeed, or in rare cases where it fails, we then fall back to using the * async worker threads for a blocking retry. */ static bool io_rw_should_retry(struct io_kiocb *req) { struct io_async_rw *io = req->async_data; struct wait_page_queue *wait = &io->wpq; struct io_rw *rw = io_kiocb_to_cmd(req, struct io_rw); struct kiocb *kiocb = &rw->kiocb; /* never retry for NOWAIT, we just complete with -EAGAIN */ if (req->flags & REQ_F_NOWAIT) return false; /* Only for buffered IO */ if (kiocb->ki_flags & (IOCB_DIRECT | IOCB_HIPRI)) return false; /* * just use poll if we can, and don't attempt if the fs doesn't * support callback based unlocks */ if (file_can_poll(req->file) || !(req->file->f_mode & FMODE_BUF_RASYNC)) return false; wait->wait.func = io_async_buf_func; wait->wait.private = req; wait->wait.flags = 0; INIT_LIST_HEAD(&wait->wait.entry); kiocb->ki_flags |= IOCB_WAITQ; kiocb->ki_flags &= ~IOCB_NOWAIT; kiocb->ki_waitq = wait; return true; } static inline int io_iter_do_read(struct io_rw *rw, struct iov_iter *iter) { struct file *file = rw->kiocb.ki_filp; if (likely(file->f_op->read_iter)) return call_read_iter(file, &rw->kiocb, iter); else if (file->f_op->read) return loop_rw_iter(READ, rw, iter); else return -EINVAL; } static bool need_complete_io(struct io_kiocb *req) { return req->flags & REQ_F_ISREG || S_ISBLK(file_inode(req->file)->i_mode); } static int io_rw_init_file(struct io_kiocb *req, fmode_t mode) { struct io_rw *rw = io_kiocb_to_cmd(req, struct io_rw); struct kiocb *kiocb = &rw->kiocb; struct io_ring_ctx *ctx = req->ctx; struct file *file = req->file; int ret; if (unlikely(!file || !(file->f_mode & mode))) return -EBADF; if (!(req->flags & REQ_F_FIXED_FILE)) req->flags |= io_file_get_flags(file); kiocb->ki_flags = file->f_iocb_flags; ret = kiocb_set_rw_flags(kiocb, rw->flags); if (unlikely(ret)) return ret; kiocb->ki_flags |= IOCB_ALLOC_CACHE; /* * If the file is marked O_NONBLOCK, still allow retry for it if it * supports async. Otherwise it's impossible to use O_NONBLOCK files * reliably. If not, or it IOCB_NOWAIT is set, don't retry. */ if ((kiocb->ki_flags & IOCB_NOWAIT) || ((file->f_flags & O_NONBLOCK) && !io_file_supports_nowait(req))) req->flags |= REQ_F_NOWAIT; if (ctx->flags & IORING_SETUP_IOPOLL) { if (!(kiocb->ki_flags & IOCB_DIRECT) || !file->f_op->iopoll) return -EOPNOTSUPP; kiocb->private = NULL; kiocb->ki_flags |= IOCB_HIPRI; kiocb->ki_complete = io_complete_rw_iopoll; req->iopoll_completed = 0; } else { if (kiocb->ki_flags & IOCB_HIPRI) return -EINVAL; kiocb->ki_complete = io_complete_rw; } return 0; } int io_read(struct io_kiocb *req, unsigned int issue_flags) { struct io_rw *rw = io_kiocb_to_cmd(req, struct io_rw); struct io_rw_state __s, *s = &__s; struct iovec *iovec; struct kiocb *kiocb = &rw->kiocb; bool force_nonblock = issue_flags & IO_URING_F_NONBLOCK; struct io_async_rw *io; ssize_t ret, ret2; loff_t *ppos; if (!req_has_async_data(req)) { ret = io_import_iovec(ITER_DEST, req, &iovec, s, issue_flags); if (unlikely(ret < 0)) return ret; } else { io = req->async_data; s = &io->s; /* * Safe and required to re-import if we're using provided * buffers, as we dropped the selected one before retry. */ if (io_do_buffer_select(req)) { ret = io_import_iovec(ITER_DEST, req, &iovec, s, issue_flags); if (unlikely(ret < 0)) return ret; } /* * We come here from an earlier attempt, restore our state to * match in case it doesn't. It's cheap enough that we don't * need to make this conditional. */ iov_iter_restore(&s->iter, &s->iter_state); iovec = NULL; } ret = io_rw_init_file(req, FMODE_READ); if (unlikely(ret)) { kfree(iovec); return ret; } req->cqe.res = iov_iter_count(&s->iter); if (force_nonblock) { /* If the file doesn't support async, just async punt */ if (unlikely(!io_file_supports_nowait(req))) { ret = io_setup_async_rw(req, iovec, s, true); return ret ?: -EAGAIN; } kiocb->ki_flags |= IOCB_NOWAIT; } else { /* Ensure we clear previously set non-block flag */ kiocb->ki_flags &= ~IOCB_NOWAIT; } ppos = io_kiocb_update_pos(req); ret = rw_verify_area(READ, req->file, ppos, req->cqe.res); if (unlikely(ret)) { kfree(iovec); return ret; } ret = io_iter_do_read(rw, &s->iter); if (ret == -EAGAIN || (req->flags & REQ_F_REISSUE)) { req->flags &= ~REQ_F_REISSUE; /* if we can poll, just do that */ if (req->opcode == IORING_OP_READ && file_can_poll(req->file)) return -EAGAIN; /* IOPOLL retry should happen for io-wq threads */ if (!force_nonblock && !(req->ctx->flags & IORING_SETUP_IOPOLL)) goto done; /* no retry on NONBLOCK nor RWF_NOWAIT */ if (req->flags & REQ_F_NOWAIT) goto done; ret = 0; } else if (ret == -EIOCBQUEUED) { if (iovec) kfree(iovec); return IOU_ISSUE_SKIP_COMPLETE; } else if (ret == req->cqe.res || ret <= 0 || !force_nonblock || (req->flags & REQ_F_NOWAIT) || !need_complete_io(req)) { /* read all, failed, already did sync or don't want to retry */ goto done; } /* * Don't depend on the iter state matching what was consumed, or being * untouched in case of error. Restore it and we'll advance it * manually if we need to. */ iov_iter_restore(&s->iter, &s->iter_state); ret2 = io_setup_async_rw(req, iovec, s, true); iovec = NULL; if (ret2) { ret = ret > 0 ? ret : ret2; goto done; } io = req->async_data; s = &io->s; /* * Now use our persistent iterator and state, if we aren't already. * We've restored and mapped the iter to match. */ do { /* * We end up here because of a partial read, either from * above or inside this loop. Advance the iter by the bytes * that were consumed. */ iov_iter_advance(&s->iter, ret); if (!iov_iter_count(&s->iter)) break; io->bytes_done += ret; iov_iter_save_state(&s->iter, &s->iter_state); /* if we can retry, do so with the callbacks armed */ if (!io_rw_should_retry(req)) { kiocb->ki_flags &= ~IOCB_WAITQ; return -EAGAIN; } req->cqe.res = iov_iter_count(&s->iter); /* * Now retry read with the IOCB_WAITQ parts set in the iocb. If * we get -EIOCBQUEUED, then we'll get a notification when the * desired page gets unlocked. We can also get a partial read * here, and if we do, then just retry at the new offset. */ ret = io_iter_do_read(rw, &s->iter); if (ret == -EIOCBQUEUED) return IOU_ISSUE_SKIP_COMPLETE; /* we got some bytes, but not all. retry. */ kiocb->ki_flags &= ~IOCB_WAITQ; iov_iter_restore(&s->iter, &s->iter_state); } while (ret > 0); done: /* it's faster to check here then delegate to kfree */ if (iovec) kfree(iovec); return kiocb_done(req, ret, issue_flags); } int io_write(struct io_kiocb *req, unsigned int issue_flags) { struct io_rw *rw = io_kiocb_to_cmd(req, struct io_rw); struct io_rw_state __s, *s = &__s; struct iovec *iovec; struct kiocb *kiocb = &rw->kiocb; bool force_nonblock = issue_flags & IO_URING_F_NONBLOCK; ssize_t ret, ret2; loff_t *ppos; if (!req_has_async_data(req)) { ret = io_import_iovec(ITER_SOURCE, req, &iovec, s, issue_flags); if (unlikely(ret < 0)) return ret; } else { struct io_async_rw *io = req->async_data; s = &io->s; iov_iter_restore(&s->iter, &s->iter_state); iovec = NULL; } ret = io_rw_init_file(req, FMODE_WRITE); if (unlikely(ret)) { kfree(iovec); return ret; } req->cqe.res = iov_iter_count(&s->iter); if (force_nonblock) { /* If the file doesn't support async, just async punt */ if (unlikely(!io_file_supports_nowait(req))) goto copy_iov; /* File path supports NOWAIT for non-direct_IO only for block devices. */ if (!(kiocb->ki_flags & IOCB_DIRECT) && !(kiocb->ki_filp->f_mode & FMODE_BUF_WASYNC) && (req->flags & REQ_F_ISREG)) goto copy_iov; kiocb->ki_flags |= IOCB_NOWAIT; } else { /* Ensure we clear previously set non-block flag */ kiocb->ki_flags &= ~IOCB_NOWAIT; } ppos = io_kiocb_update_pos(req); ret = rw_verify_area(WRITE, req->file, ppos, req->cqe.res); if (unlikely(ret)) { kfree(iovec); return ret; } if (req->flags & REQ_F_ISREG) kiocb_start_write(kiocb); kiocb->ki_flags |= IOCB_WRITE; if (likely(req->file->f_op->write_iter)) ret2 = call_write_iter(req->file, kiocb, &s->iter); else if (req->file->f_op->write) ret2 = loop_rw_iter(WRITE, rw, &s->iter); else ret2 = -EINVAL; if (req->flags & REQ_F_REISSUE) { req->flags &= ~REQ_F_REISSUE; ret2 = -EAGAIN; } /* * Raw bdev writes will return -EOPNOTSUPP for IOCB_NOWAIT. Just * retry them without IOCB_NOWAIT. */ if (ret2 == -EOPNOTSUPP && (kiocb->ki_flags & IOCB_NOWAIT)) ret2 = -EAGAIN; /* no retry on NONBLOCK nor RWF_NOWAIT */ if (ret2 == -EAGAIN && (req->flags & REQ_F_NOWAIT)) goto done; if (!force_nonblock || ret2 != -EAGAIN) { /* IOPOLL retry should happen for io-wq threads */ if (ret2 == -EAGAIN && (req->ctx->flags & IORING_SETUP_IOPOLL)) goto copy_iov; if (ret2 != req->cqe.res && ret2 >= 0 && need_complete_io(req)) { struct io_async_rw *io; trace_io_uring_short_write(req->ctx, kiocb->ki_pos - ret2, req->cqe.res, ret2); /* This is a partial write. The file pos has already been * updated, setup the async struct to complete the request * in the worker. Also update bytes_done to account for * the bytes already written. */ iov_iter_save_state(&s->iter, &s->iter_state); ret = io_setup_async_rw(req, iovec, s, true); io = req->async_data; if (io) io->bytes_done += ret2; if (kiocb->ki_flags & IOCB_WRITE) io_req_end_write(req); return ret ? ret : -EAGAIN; } done: ret = kiocb_done(req, ret2, issue_flags); } else { copy_iov: iov_iter_restore(&s->iter, &s->iter_state); ret = io_setup_async_rw(req, iovec, s, false); if (!ret) { if (kiocb->ki_flags & IOCB_WRITE) io_req_end_write(req); return -EAGAIN; } return ret; } /* it's reportedly faster than delegating the null check to kfree() */ if (iovec) kfree(iovec); return ret; } void io_rw_fail(struct io_kiocb *req) { int res; res = io_fixup_rw_res(req, req->cqe.res); io_req_set_res(req, res, req->cqe.flags); } int io_do_iopoll(struct io_ring_ctx *ctx, bool force_nonspin) { struct io_wq_work_node *pos, *start, *prev; unsigned int poll_flags = 0; DEFINE_IO_COMP_BATCH(iob); int nr_events = 0; /* * Only spin for completions if we don't have multiple devices hanging * off our complete list. */ if (ctx->poll_multi_queue || force_nonspin) poll_flags |= BLK_POLL_ONESHOT; wq_list_for_each(pos, start, &ctx->iopoll_list) { struct io_kiocb *req = container_of(pos, struct io_kiocb, comp_list); struct file *file = req->file; int ret; /* * Move completed and retryable entries to our local lists. * If we find a request that requires polling, break out * and complete those lists first, if we have entries there. */ if (READ_ONCE(req->iopoll_completed)) break; if (req->opcode == IORING_OP_URING_CMD) { struct io_uring_cmd *ioucmd; ioucmd = io_kiocb_to_cmd(req, struct io_uring_cmd); ret = file->f_op->uring_cmd_iopoll(ioucmd, &iob, poll_flags); } else { struct io_rw *rw = io_kiocb_to_cmd(req, struct io_rw); ret = file->f_op->iopoll(&rw->kiocb, &iob, poll_flags); } if (unlikely(ret < 0)) return ret; else if (ret) poll_flags |= BLK_POLL_ONESHOT; /* iopoll may have completed current req */ if (!rq_list_empty(iob.req_list) || READ_ONCE(req->iopoll_completed)) break; } if (!rq_list_empty(iob.req_list)) iob.complete(&iob); else if (!pos) return 0; prev = start; wq_list_for_each_resume(pos, prev) { struct io_kiocb *req = container_of(pos, struct io_kiocb, comp_list); /* order with io_complete_rw_iopoll(), e.g. ->result updates */ if (!smp_load_acquire(&req->iopoll_completed)) break; nr_events++; req->cqe.flags = io_put_kbuf(req, 0); } if (unlikely(!nr_events)) return 0; pos = start ? start->next : ctx->iopoll_list.first; wq_list_cut(&ctx->iopoll_list, prev, start); if (WARN_ON_ONCE(!wq_list_empty(&ctx->submit_state.compl_reqs))) return 0; ctx->submit_state.compl_reqs.first = pos; __io_submit_flush_completions(ctx); return nr_events; } |