1 // SPDX-License-Identifier: GPL-2.0 2 #include <linux/kernel.h> 3 #include <linux/errno.h> 4 #include <linux/fs.h> 5 #include <linux/file.h> 6 #include <linux/mm.h> 7 #include <linux/slab.h> 8 #include <linux/nospec.h> 9 #include <linux/hugetlb.h> 10 #include <linux/compat.h> 11 #include <linux/io_uring.h> 12 13 #include <uapi/linux/io_uring.h> 14 15 #include "io_uring.h" 16 #include "alloc_cache.h" 17 #include "openclose.h" 18 #include "rsrc.h" 19 #include "memmap.h" 20 21 struct io_rsrc_update { 22 struct file *file; 23 u64 arg; 24 u32 nr_args; 25 u32 offset; 26 }; 27 28 static void io_rsrc_buf_put(struct io_ring_ctx *ctx, struct io_rsrc_put *prsrc); 29 static int io_sqe_buffer_register(struct io_ring_ctx *ctx, struct iovec *iov, 30 struct io_mapped_ubuf **pimu, 31 struct page **last_hpage); 32 33 /* only define max */ 34 #define IORING_MAX_FIXED_FILES (1U << 20) 35 #define IORING_MAX_REG_BUFFERS (1U << 14) 36 37 static const struct io_mapped_ubuf dummy_ubuf = { 38 /* set invalid range, so io_import_fixed() fails meeting it */ 39 .ubuf = -1UL, 40 .ubuf_end = 0, 41 }; 42 43 int __io_account_mem(struct user_struct *user, unsigned long nr_pages) 44 { 45 unsigned long page_limit, cur_pages, new_pages; 46 47 if (!nr_pages) 48 return 0; 49 50 /* Don't allow more pages than we can safely lock */ 51 page_limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT; 52 53 cur_pages = atomic_long_read(&user->locked_vm); 54 do { 55 new_pages = cur_pages + nr_pages; 56 if (new_pages > page_limit) 57 return -ENOMEM; 58 } while (!atomic_long_try_cmpxchg(&user->locked_vm, 59 &cur_pages, new_pages)); 60 return 0; 61 } 62 63 static void io_unaccount_mem(struct io_ring_ctx *ctx, unsigned long nr_pages) 64 { 65 if (ctx->user) 66 __io_unaccount_mem(ctx->user, nr_pages); 67 68 if (ctx->mm_account) 69 atomic64_sub(nr_pages, &ctx->mm_account->pinned_vm); 70 } 71 72 static int io_account_mem(struct io_ring_ctx *ctx, unsigned long nr_pages) 73 { 74 int ret; 75 76 if (ctx->user) { 77 ret = __io_account_mem(ctx->user, nr_pages); 78 if (ret) 79 return ret; 80 } 81 82 if (ctx->mm_account) 83 atomic64_add(nr_pages, &ctx->mm_account->pinned_vm); 84 85 return 0; 86 } 87 88 static int io_buffer_validate(struct iovec *iov) 89 { 90 unsigned long tmp, acct_len = iov->iov_len + (PAGE_SIZE - 1); 91 92 /* 93 * Don't impose further limits on the size and buffer 94 * constraints here, we'll -EINVAL later when IO is 95 * submitted if they are wrong. 96 */ 97 if (!iov->iov_base) 98 return iov->iov_len ? -EFAULT : 0; 99 if (!iov->iov_len) 100 return -EFAULT; 101 102 /* arbitrary limit, but we need something */ 103 if (iov->iov_len > SZ_1G) 104 return -EFAULT; 105 106 if (check_add_overflow((unsigned long)iov->iov_base, acct_len, &tmp)) 107 return -EOVERFLOW; 108 109 return 0; 110 } 111 112 static void io_buffer_unmap(struct io_ring_ctx *ctx, struct io_mapped_ubuf **slot) 113 { 114 struct io_mapped_ubuf *imu = *slot; 115 unsigned int i; 116 117 if (imu != &dummy_ubuf) { 118 for (i = 0; i < imu->nr_bvecs; i++) 119 unpin_user_page(imu->bvec[i].bv_page); 120 if (imu->acct_pages) 121 io_unaccount_mem(ctx, imu->acct_pages); 122 kvfree(imu); 123 } 124 *slot = NULL; 125 } 126 127 static void io_rsrc_put_work(struct io_rsrc_node *node) 128 { 129 struct io_rsrc_put *prsrc = &node->item; 130 131 if (prsrc->tag) 132 io_post_aux_cqe(node->ctx, prsrc->tag, 0, 0); 133 134 switch (node->type) { 135 case IORING_RSRC_FILE: 136 fput(prsrc->file); 137 break; 138 case IORING_RSRC_BUFFER: 139 io_rsrc_buf_put(node->ctx, prsrc); 140 break; 141 default: 142 WARN_ON_ONCE(1); 143 break; 144 } 145 } 146 147 void io_rsrc_node_destroy(struct io_ring_ctx *ctx, struct io_rsrc_node *node) 148 { 149 if (!io_alloc_cache_put(&ctx->rsrc_node_cache, node)) 150 kfree(node); 151 } 152 153 void io_rsrc_node_ref_zero(struct io_rsrc_node *node) 154 __must_hold(&node->ctx->uring_lock) 155 { 156 struct io_ring_ctx *ctx = node->ctx; 157 158 while (!list_empty(&ctx->rsrc_ref_list)) { 159 node = list_first_entry(&ctx->rsrc_ref_list, 160 struct io_rsrc_node, node); 161 /* recycle ref nodes in order */ 162 if (node->refs) 163 break; 164 list_del(&node->node); 165 166 if (likely(!node->empty)) 167 io_rsrc_put_work(node); 168 io_rsrc_node_destroy(ctx, node); 169 } 170 if (list_empty(&ctx->rsrc_ref_list) && unlikely(ctx->rsrc_quiesce)) 171 wake_up_all(&ctx->rsrc_quiesce_wq); 172 } 173 174 struct io_rsrc_node *io_rsrc_node_alloc(struct io_ring_ctx *ctx) 175 { 176 struct io_rsrc_node *ref_node; 177 178 ref_node = io_alloc_cache_get(&ctx->rsrc_node_cache); 179 if (!ref_node) { 180 ref_node = kzalloc(sizeof(*ref_node), GFP_KERNEL); 181 if (!ref_node) 182 return NULL; 183 } 184 185 ref_node->ctx = ctx; 186 ref_node->empty = 0; 187 ref_node->refs = 1; 188 return ref_node; 189 } 190 191 __cold static int io_rsrc_ref_quiesce(struct io_rsrc_data *data, 192 struct io_ring_ctx *ctx) 193 { 194 struct io_rsrc_node *backup; 195 DEFINE_WAIT(we); 196 int ret; 197 198 /* As We may drop ->uring_lock, other task may have started quiesce */ 199 if (data->quiesce) 200 return -ENXIO; 201 202 backup = io_rsrc_node_alloc(ctx); 203 if (!backup) 204 return -ENOMEM; 205 ctx->rsrc_node->empty = true; 206 ctx->rsrc_node->type = -1; 207 list_add_tail(&ctx->rsrc_node->node, &ctx->rsrc_ref_list); 208 io_put_rsrc_node(ctx, ctx->rsrc_node); 209 ctx->rsrc_node = backup; 210 211 if (list_empty(&ctx->rsrc_ref_list)) 212 return 0; 213 214 if (ctx->flags & IORING_SETUP_DEFER_TASKRUN) { 215 atomic_set(&ctx->cq_wait_nr, 1); 216 smp_mb(); 217 } 218 219 ctx->rsrc_quiesce++; 220 data->quiesce = true; 221 do { 222 prepare_to_wait(&ctx->rsrc_quiesce_wq, &we, TASK_INTERRUPTIBLE); 223 mutex_unlock(&ctx->uring_lock); 224 225 ret = io_run_task_work_sig(ctx); 226 if (ret < 0) { 227 finish_wait(&ctx->rsrc_quiesce_wq, &we); 228 mutex_lock(&ctx->uring_lock); 229 if (list_empty(&ctx->rsrc_ref_list)) 230 ret = 0; 231 break; 232 } 233 234 schedule(); 235 mutex_lock(&ctx->uring_lock); 236 ret = 0; 237 } while (!list_empty(&ctx->rsrc_ref_list)); 238 239 finish_wait(&ctx->rsrc_quiesce_wq, &we); 240 data->quiesce = false; 241 ctx->rsrc_quiesce--; 242 243 if (ctx->flags & IORING_SETUP_DEFER_TASKRUN) { 244 atomic_set(&ctx->cq_wait_nr, 0); 245 smp_mb(); 246 } 247 return ret; 248 } 249 250 static void io_free_page_table(void **table, size_t size) 251 { 252 unsigned i, nr_tables = DIV_ROUND_UP(size, PAGE_SIZE); 253 254 for (i = 0; i < nr_tables; i++) 255 kfree(table[i]); 256 kfree(table); 257 } 258 259 static void io_rsrc_data_free(struct io_rsrc_data *data) 260 { 261 size_t size = data->nr * sizeof(data->tags[0][0]); 262 263 if (data->tags) 264 io_free_page_table((void **)data->tags, size); 265 kfree(data); 266 } 267 268 static __cold void **io_alloc_page_table(size_t size) 269 { 270 unsigned i, nr_tables = DIV_ROUND_UP(size, PAGE_SIZE); 271 size_t init_size = size; 272 void **table; 273 274 table = kcalloc(nr_tables, sizeof(*table), GFP_KERNEL_ACCOUNT); 275 if (!table) 276 return NULL; 277 278 for (i = 0; i < nr_tables; i++) { 279 unsigned int this_size = min_t(size_t, size, PAGE_SIZE); 280 281 table[i] = kzalloc(this_size, GFP_KERNEL_ACCOUNT); 282 if (!table[i]) { 283 io_free_page_table(table, init_size); 284 return NULL; 285 } 286 size -= this_size; 287 } 288 return table; 289 } 290 291 __cold static int io_rsrc_data_alloc(struct io_ring_ctx *ctx, int type, 292 u64 __user *utags, 293 unsigned nr, struct io_rsrc_data **pdata) 294 { 295 struct io_rsrc_data *data; 296 int ret = 0; 297 unsigned i; 298 299 data = kzalloc(sizeof(*data), GFP_KERNEL); 300 if (!data) 301 return -ENOMEM; 302 data->tags = (u64 **)io_alloc_page_table(nr * sizeof(data->tags[0][0])); 303 if (!data->tags) { 304 kfree(data); 305 return -ENOMEM; 306 } 307 308 data->nr = nr; 309 data->ctx = ctx; 310 data->rsrc_type = type; 311 if (utags) { 312 ret = -EFAULT; 313 for (i = 0; i < nr; i++) { 314 u64 *tag_slot = io_get_tag_slot(data, i); 315 316 if (copy_from_user(tag_slot, &utags[i], 317 sizeof(*tag_slot))) 318 goto fail; 319 } 320 } 321 *pdata = data; 322 return 0; 323 fail: 324 io_rsrc_data_free(data); 325 return ret; 326 } 327 328 static int __io_sqe_files_update(struct io_ring_ctx *ctx, 329 struct io_uring_rsrc_update2 *up, 330 unsigned nr_args) 331 { 332 u64 __user *tags = u64_to_user_ptr(up->tags); 333 __s32 __user *fds = u64_to_user_ptr(up->data); 334 struct io_rsrc_data *data = ctx->file_data; 335 struct io_fixed_file *file_slot; 336 int fd, i, err = 0; 337 unsigned int done; 338 339 if (!ctx->file_data) 340 return -ENXIO; 341 if (up->offset + nr_args > ctx->nr_user_files) 342 return -EINVAL; 343 344 for (done = 0; done < nr_args; done++) { 345 u64 tag = 0; 346 347 if ((tags && copy_from_user(&tag, &tags[done], sizeof(tag))) || 348 copy_from_user(&fd, &fds[done], sizeof(fd))) { 349 err = -EFAULT; 350 break; 351 } 352 if ((fd == IORING_REGISTER_FILES_SKIP || fd == -1) && tag) { 353 err = -EINVAL; 354 break; 355 } 356 if (fd == IORING_REGISTER_FILES_SKIP) 357 continue; 358 359 i = array_index_nospec(up->offset + done, ctx->nr_user_files); 360 file_slot = io_fixed_file_slot(&ctx->file_table, i); 361 362 if (file_slot->file_ptr) { 363 err = io_queue_rsrc_removal(data, i, 364 io_slot_file(file_slot)); 365 if (err) 366 break; 367 file_slot->file_ptr = 0; 368 io_file_bitmap_clear(&ctx->file_table, i); 369 } 370 if (fd != -1) { 371 struct file *file = fget(fd); 372 373 if (!file) { 374 err = -EBADF; 375 break; 376 } 377 /* 378 * Don't allow io_uring instances to be registered. 379 */ 380 if (io_is_uring_fops(file)) { 381 fput(file); 382 err = -EBADF; 383 break; 384 } 385 *io_get_tag_slot(data, i) = tag; 386 io_fixed_file_set(file_slot, file); 387 io_file_bitmap_set(&ctx->file_table, i); 388 } 389 } 390 return done ? done : err; 391 } 392 393 static int __io_sqe_buffers_update(struct io_ring_ctx *ctx, 394 struct io_uring_rsrc_update2 *up, 395 unsigned int nr_args) 396 { 397 struct iovec __user *uvec = u64_to_user_ptr(up->data); 398 u64 __user *tags = u64_to_user_ptr(up->tags); 399 struct iovec fast_iov, *iov; 400 struct page *last_hpage = NULL; 401 __u32 done; 402 int i, err; 403 404 if (!ctx->buf_data) 405 return -ENXIO; 406 if (up->offset + nr_args > ctx->nr_user_bufs) 407 return -EINVAL; 408 409 for (done = 0; done < nr_args; done++) { 410 struct io_mapped_ubuf *imu; 411 u64 tag = 0; 412 413 iov = iovec_from_user(&uvec[done], 1, 1, &fast_iov, ctx->compat); 414 if (IS_ERR(iov)) { 415 err = PTR_ERR(iov); 416 break; 417 } 418 if (tags && copy_from_user(&tag, &tags[done], sizeof(tag))) { 419 err = -EFAULT; 420 break; 421 } 422 err = io_buffer_validate(iov); 423 if (err) 424 break; 425 if (!iov->iov_base && tag) { 426 err = -EINVAL; 427 break; 428 } 429 err = io_sqe_buffer_register(ctx, iov, &imu, &last_hpage); 430 if (err) 431 break; 432 433 i = array_index_nospec(up->offset + done, ctx->nr_user_bufs); 434 if (ctx->user_bufs[i] != &dummy_ubuf) { 435 err = io_queue_rsrc_removal(ctx->buf_data, i, 436 ctx->user_bufs[i]); 437 if (unlikely(err)) { 438 io_buffer_unmap(ctx, &imu); 439 break; 440 } 441 ctx->user_bufs[i] = (struct io_mapped_ubuf *)&dummy_ubuf; 442 } 443 444 ctx->user_bufs[i] = imu; 445 *io_get_tag_slot(ctx->buf_data, i) = tag; 446 } 447 return done ? done : err; 448 } 449 450 static int __io_register_rsrc_update(struct io_ring_ctx *ctx, unsigned type, 451 struct io_uring_rsrc_update2 *up, 452 unsigned nr_args) 453 { 454 __u32 tmp; 455 456 lockdep_assert_held(&ctx->uring_lock); 457 458 if (check_add_overflow(up->offset, nr_args, &tmp)) 459 return -EOVERFLOW; 460 461 switch (type) { 462 case IORING_RSRC_FILE: 463 return __io_sqe_files_update(ctx, up, nr_args); 464 case IORING_RSRC_BUFFER: 465 return __io_sqe_buffers_update(ctx, up, nr_args); 466 } 467 return -EINVAL; 468 } 469 470 int io_register_files_update(struct io_ring_ctx *ctx, void __user *arg, 471 unsigned nr_args) 472 { 473 struct io_uring_rsrc_update2 up; 474 475 if (!nr_args) 476 return -EINVAL; 477 memset(&up, 0, sizeof(up)); 478 if (copy_from_user(&up, arg, sizeof(struct io_uring_rsrc_update))) 479 return -EFAULT; 480 if (up.resv || up.resv2) 481 return -EINVAL; 482 return __io_register_rsrc_update(ctx, IORING_RSRC_FILE, &up, nr_args); 483 } 484 485 int io_register_rsrc_update(struct io_ring_ctx *ctx, void __user *arg, 486 unsigned size, unsigned type) 487 { 488 struct io_uring_rsrc_update2 up; 489 490 if (size != sizeof(up)) 491 return -EINVAL; 492 if (copy_from_user(&up, arg, sizeof(up))) 493 return -EFAULT; 494 if (!up.nr || up.resv || up.resv2) 495 return -EINVAL; 496 return __io_register_rsrc_update(ctx, type, &up, up.nr); 497 } 498 499 __cold int io_register_rsrc(struct io_ring_ctx *ctx, void __user *arg, 500 unsigned int size, unsigned int type) 501 { 502 struct io_uring_rsrc_register rr; 503 504 /* keep it extendible */ 505 if (size != sizeof(rr)) 506 return -EINVAL; 507 508 memset(&rr, 0, sizeof(rr)); 509 if (copy_from_user(&rr, arg, size)) 510 return -EFAULT; 511 if (!rr.nr || rr.resv2) 512 return -EINVAL; 513 if (rr.flags & ~IORING_RSRC_REGISTER_SPARSE) 514 return -EINVAL; 515 516 switch (type) { 517 case IORING_RSRC_FILE: 518 if (rr.flags & IORING_RSRC_REGISTER_SPARSE && rr.data) 519 break; 520 return io_sqe_files_register(ctx, u64_to_user_ptr(rr.data), 521 rr.nr, u64_to_user_ptr(rr.tags)); 522 case IORING_RSRC_BUFFER: 523 if (rr.flags & IORING_RSRC_REGISTER_SPARSE && rr.data) 524 break; 525 return io_sqe_buffers_register(ctx, u64_to_user_ptr(rr.data), 526 rr.nr, u64_to_user_ptr(rr.tags)); 527 } 528 return -EINVAL; 529 } 530 531 int io_files_update_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe) 532 { 533 struct io_rsrc_update *up = io_kiocb_to_cmd(req, struct io_rsrc_update); 534 535 if (unlikely(req->flags & (REQ_F_FIXED_FILE | REQ_F_BUFFER_SELECT))) 536 return -EINVAL; 537 if (sqe->rw_flags || sqe->splice_fd_in) 538 return -EINVAL; 539 540 up->offset = READ_ONCE(sqe->off); 541 up->nr_args = READ_ONCE(sqe->len); 542 if (!up->nr_args) 543 return -EINVAL; 544 up->arg = READ_ONCE(sqe->addr); 545 return 0; 546 } 547 548 static int io_files_update_with_index_alloc(struct io_kiocb *req, 549 unsigned int issue_flags) 550 { 551 struct io_rsrc_update *up = io_kiocb_to_cmd(req, struct io_rsrc_update); 552 __s32 __user *fds = u64_to_user_ptr(up->arg); 553 unsigned int done; 554 struct file *file; 555 int ret, fd; 556 557 if (!req->ctx->file_data) 558 return -ENXIO; 559 560 for (done = 0; done < up->nr_args; done++) { 561 if (copy_from_user(&fd, &fds[done], sizeof(fd))) { 562 ret = -EFAULT; 563 break; 564 } 565 566 file = fget(fd); 567 if (!file) { 568 ret = -EBADF; 569 break; 570 } 571 ret = io_fixed_fd_install(req, issue_flags, file, 572 IORING_FILE_INDEX_ALLOC); 573 if (ret < 0) 574 break; 575 if (copy_to_user(&fds[done], &ret, sizeof(ret))) { 576 __io_close_fixed(req->ctx, issue_flags, ret); 577 ret = -EFAULT; 578 break; 579 } 580 } 581 582 if (done) 583 return done; 584 return ret; 585 } 586 587 int io_files_update(struct io_kiocb *req, unsigned int issue_flags) 588 { 589 struct io_rsrc_update *up = io_kiocb_to_cmd(req, struct io_rsrc_update); 590 struct io_ring_ctx *ctx = req->ctx; 591 struct io_uring_rsrc_update2 up2; 592 int ret; 593 594 up2.offset = up->offset; 595 up2.data = up->arg; 596 up2.nr = 0; 597 up2.tags = 0; 598 up2.resv = 0; 599 up2.resv2 = 0; 600 601 if (up->offset == IORING_FILE_INDEX_ALLOC) { 602 ret = io_files_update_with_index_alloc(req, issue_flags); 603 } else { 604 io_ring_submit_lock(ctx, issue_flags); 605 ret = __io_register_rsrc_update(ctx, IORING_RSRC_FILE, 606 &up2, up->nr_args); 607 io_ring_submit_unlock(ctx, issue_flags); 608 } 609 610 if (ret < 0) 611 req_set_fail(req); 612 io_req_set_res(req, ret, 0); 613 return IOU_OK; 614 } 615 616 int io_queue_rsrc_removal(struct io_rsrc_data *data, unsigned idx, void *rsrc) 617 { 618 struct io_ring_ctx *ctx = data->ctx; 619 struct io_rsrc_node *node = ctx->rsrc_node; 620 u64 *tag_slot = io_get_tag_slot(data, idx); 621 622 ctx->rsrc_node = io_rsrc_node_alloc(ctx); 623 if (unlikely(!ctx->rsrc_node)) { 624 ctx->rsrc_node = node; 625 return -ENOMEM; 626 } 627 628 node->item.rsrc = rsrc; 629 node->type = data->rsrc_type; 630 node->item.tag = *tag_slot; 631 *tag_slot = 0; 632 list_add_tail(&node->node, &ctx->rsrc_ref_list); 633 io_put_rsrc_node(ctx, node); 634 return 0; 635 } 636 637 void __io_sqe_files_unregister(struct io_ring_ctx *ctx) 638 { 639 int i; 640 641 for (i = 0; i < ctx->nr_user_files; i++) { 642 struct file *file = io_file_from_index(&ctx->file_table, i); 643 644 if (!file) 645 continue; 646 io_file_bitmap_clear(&ctx->file_table, i); 647 fput(file); 648 } 649 650 io_free_file_tables(&ctx->file_table); 651 io_file_table_set_alloc_range(ctx, 0, 0); 652 io_rsrc_data_free(ctx->file_data); 653 ctx->file_data = NULL; 654 ctx->nr_user_files = 0; 655 } 656 657 int io_sqe_files_unregister(struct io_ring_ctx *ctx) 658 { 659 unsigned nr = ctx->nr_user_files; 660 int ret; 661 662 if (!ctx->file_data) 663 return -ENXIO; 664 665 /* 666 * Quiesce may unlock ->uring_lock, and while it's not held 667 * prevent new requests using the table. 668 */ 669 ctx->nr_user_files = 0; 670 ret = io_rsrc_ref_quiesce(ctx->file_data, ctx); 671 ctx->nr_user_files = nr; 672 if (!ret) 673 __io_sqe_files_unregister(ctx); 674 return ret; 675 } 676 677 int io_sqe_files_register(struct io_ring_ctx *ctx, void __user *arg, 678 unsigned nr_args, u64 __user *tags) 679 { 680 __s32 __user *fds = (__s32 __user *) arg; 681 struct file *file; 682 int fd, ret; 683 unsigned i; 684 685 if (ctx->file_data) 686 return -EBUSY; 687 if (!nr_args) 688 return -EINVAL; 689 if (nr_args > IORING_MAX_FIXED_FILES) 690 return -EMFILE; 691 if (nr_args > rlimit(RLIMIT_NOFILE)) 692 return -EMFILE; 693 ret = io_rsrc_data_alloc(ctx, IORING_RSRC_FILE, tags, nr_args, 694 &ctx->file_data); 695 if (ret) 696 return ret; 697 698 if (!io_alloc_file_tables(&ctx->file_table, nr_args)) { 699 io_rsrc_data_free(ctx->file_data); 700 ctx->file_data = NULL; 701 return -ENOMEM; 702 } 703 704 for (i = 0; i < nr_args; i++, ctx->nr_user_files++) { 705 struct io_fixed_file *file_slot; 706 707 if (fds && copy_from_user(&fd, &fds[i], sizeof(fd))) { 708 ret = -EFAULT; 709 goto fail; 710 } 711 /* allow sparse sets */ 712 if (!fds || fd == -1) { 713 ret = -EINVAL; 714 if (unlikely(*io_get_tag_slot(ctx->file_data, i))) 715 goto fail; 716 continue; 717 } 718 719 file = fget(fd); 720 ret = -EBADF; 721 if (unlikely(!file)) 722 goto fail; 723 724 /* 725 * Don't allow io_uring instances to be registered. 726 */ 727 if (io_is_uring_fops(file)) { 728 fput(file); 729 goto fail; 730 } 731 file_slot = io_fixed_file_slot(&ctx->file_table, i); 732 io_fixed_file_set(file_slot, file); 733 io_file_bitmap_set(&ctx->file_table, i); 734 } 735 736 /* default it to the whole table */ 737 io_file_table_set_alloc_range(ctx, 0, ctx->nr_user_files); 738 return 0; 739 fail: 740 __io_sqe_files_unregister(ctx); 741 return ret; 742 } 743 744 static void io_rsrc_buf_put(struct io_ring_ctx *ctx, struct io_rsrc_put *prsrc) 745 { 746 io_buffer_unmap(ctx, &prsrc->buf); 747 prsrc->buf = NULL; 748 } 749 750 void __io_sqe_buffers_unregister(struct io_ring_ctx *ctx) 751 { 752 unsigned int i; 753 754 for (i = 0; i < ctx->nr_user_bufs; i++) 755 io_buffer_unmap(ctx, &ctx->user_bufs[i]); 756 kfree(ctx->user_bufs); 757 io_rsrc_data_free(ctx->buf_data); 758 ctx->user_bufs = NULL; 759 ctx->buf_data = NULL; 760 ctx->nr_user_bufs = 0; 761 } 762 763 int io_sqe_buffers_unregister(struct io_ring_ctx *ctx) 764 { 765 unsigned nr = ctx->nr_user_bufs; 766 int ret; 767 768 if (!ctx->buf_data) 769 return -ENXIO; 770 771 /* 772 * Quiesce may unlock ->uring_lock, and while it's not held 773 * prevent new requests using the table. 774 */ 775 ctx->nr_user_bufs = 0; 776 ret = io_rsrc_ref_quiesce(ctx->buf_data, ctx); 777 ctx->nr_user_bufs = nr; 778 if (!ret) 779 __io_sqe_buffers_unregister(ctx); 780 return ret; 781 } 782 783 /* 784 * Not super efficient, but this is just a registration time. And we do cache 785 * the last compound head, so generally we'll only do a full search if we don't 786 * match that one. 787 * 788 * We check if the given compound head page has already been accounted, to 789 * avoid double accounting it. This allows us to account the full size of the 790 * page, not just the constituent pages of a huge page. 791 */ 792 static bool headpage_already_acct(struct io_ring_ctx *ctx, struct page **pages, 793 int nr_pages, struct page *hpage) 794 { 795 int i, j; 796 797 /* check current page array */ 798 for (i = 0; i < nr_pages; i++) { 799 if (!PageCompound(pages[i])) 800 continue; 801 if (compound_head(pages[i]) == hpage) 802 return true; 803 } 804 805 /* check previously registered pages */ 806 for (i = 0; i < ctx->nr_user_bufs; i++) { 807 struct io_mapped_ubuf *imu = ctx->user_bufs[i]; 808 809 for (j = 0; j < imu->nr_bvecs; j++) { 810 if (!PageCompound(imu->bvec[j].bv_page)) 811 continue; 812 if (compound_head(imu->bvec[j].bv_page) == hpage) 813 return true; 814 } 815 } 816 817 return false; 818 } 819 820 static int io_buffer_account_pin(struct io_ring_ctx *ctx, struct page **pages, 821 int nr_pages, struct io_mapped_ubuf *imu, 822 struct page **last_hpage) 823 { 824 int i, ret; 825 826 imu->acct_pages = 0; 827 for (i = 0; i < nr_pages; i++) { 828 if (!PageCompound(pages[i])) { 829 imu->acct_pages++; 830 } else { 831 struct page *hpage; 832 833 hpage = compound_head(pages[i]); 834 if (hpage == *last_hpage) 835 continue; 836 *last_hpage = hpage; 837 if (headpage_already_acct(ctx, pages, i, hpage)) 838 continue; 839 imu->acct_pages += page_size(hpage) >> PAGE_SHIFT; 840 } 841 } 842 843 if (!imu->acct_pages) 844 return 0; 845 846 ret = io_account_mem(ctx, imu->acct_pages); 847 if (ret) 848 imu->acct_pages = 0; 849 return ret; 850 } 851 852 static int io_sqe_buffer_register(struct io_ring_ctx *ctx, struct iovec *iov, 853 struct io_mapped_ubuf **pimu, 854 struct page **last_hpage) 855 { 856 struct io_mapped_ubuf *imu = NULL; 857 struct page **pages = NULL; 858 unsigned long off; 859 size_t size; 860 int ret, nr_pages, i; 861 struct folio *folio = NULL; 862 863 *pimu = (struct io_mapped_ubuf *)&dummy_ubuf; 864 if (!iov->iov_base) 865 return 0; 866 867 ret = -ENOMEM; 868 pages = io_pin_pages((unsigned long) iov->iov_base, iov->iov_len, 869 &nr_pages); 870 if (IS_ERR(pages)) { 871 ret = PTR_ERR(pages); 872 pages = NULL; 873 goto done; 874 } 875 876 /* If it's a huge page, try to coalesce them into a single bvec entry */ 877 if (nr_pages > 1) { 878 folio = page_folio(pages[0]); 879 for (i = 1; i < nr_pages; i++) { 880 /* 881 * Pages must be consecutive and on the same folio for 882 * this to work 883 */ 884 if (page_folio(pages[i]) != folio || 885 pages[i] != pages[i - 1] + 1) { 886 folio = NULL; 887 break; 888 } 889 } 890 if (folio) { 891 /* 892 * The pages are bound to the folio, it doesn't 893 * actually unpin them but drops all but one reference, 894 * which is usually put down by io_buffer_unmap(). 895 * Note, needs a better helper. 896 */ 897 unpin_user_pages(&pages[1], nr_pages - 1); 898 nr_pages = 1; 899 } 900 } 901 902 imu = kvmalloc(struct_size(imu, bvec, nr_pages), GFP_KERNEL); 903 if (!imu) 904 goto done; 905 906 ret = io_buffer_account_pin(ctx, pages, nr_pages, imu, last_hpage); 907 if (ret) { 908 unpin_user_pages(pages, nr_pages); 909 goto done; 910 } 911 912 off = (unsigned long) iov->iov_base & ~PAGE_MASK; 913 size = iov->iov_len; 914 /* store original address for later verification */ 915 imu->ubuf = (unsigned long) iov->iov_base; 916 imu->ubuf_end = imu->ubuf + iov->iov_len; 917 imu->nr_bvecs = nr_pages; 918 *pimu = imu; 919 ret = 0; 920 921 if (folio) { 922 bvec_set_page(&imu->bvec[0], pages[0], size, off); 923 goto done; 924 } 925 for (i = 0; i < nr_pages; i++) { 926 size_t vec_len; 927 928 vec_len = min_t(size_t, size, PAGE_SIZE - off); 929 bvec_set_page(&imu->bvec[i], pages[i], vec_len, off); 930 off = 0; 931 size -= vec_len; 932 } 933 done: 934 if (ret) 935 kvfree(imu); 936 kvfree(pages); 937 return ret; 938 } 939 940 static int io_buffers_map_alloc(struct io_ring_ctx *ctx, unsigned int nr_args) 941 { 942 ctx->user_bufs = kcalloc(nr_args, sizeof(*ctx->user_bufs), GFP_KERNEL); 943 return ctx->user_bufs ? 0 : -ENOMEM; 944 } 945 946 int io_sqe_buffers_register(struct io_ring_ctx *ctx, void __user *arg, 947 unsigned int nr_args, u64 __user *tags) 948 { 949 struct page *last_hpage = NULL; 950 struct io_rsrc_data *data; 951 struct iovec fast_iov, *iov = &fast_iov; 952 const struct iovec __user *uvec = (struct iovec * __user) arg; 953 int i, ret; 954 955 BUILD_BUG_ON(IORING_MAX_REG_BUFFERS >= (1u << 16)); 956 957 if (ctx->user_bufs) 958 return -EBUSY; 959 if (!nr_args || nr_args > IORING_MAX_REG_BUFFERS) 960 return -EINVAL; 961 ret = io_rsrc_data_alloc(ctx, IORING_RSRC_BUFFER, tags, nr_args, &data); 962 if (ret) 963 return ret; 964 ret = io_buffers_map_alloc(ctx, nr_args); 965 if (ret) { 966 io_rsrc_data_free(data); 967 return ret; 968 } 969 970 if (!arg) 971 memset(iov, 0, sizeof(*iov)); 972 973 for (i = 0; i < nr_args; i++, ctx->nr_user_bufs++) { 974 if (arg) { 975 iov = iovec_from_user(&uvec[i], 1, 1, &fast_iov, ctx->compat); 976 if (IS_ERR(iov)) { 977 ret = PTR_ERR(iov); 978 break; 979 } 980 ret = io_buffer_validate(iov); 981 if (ret) 982 break; 983 } 984 985 if (!iov->iov_base && *io_get_tag_slot(data, i)) { 986 ret = -EINVAL; 987 break; 988 } 989 990 ret = io_sqe_buffer_register(ctx, iov, &ctx->user_bufs[i], 991 &last_hpage); 992 if (ret) 993 break; 994 } 995 996 WARN_ON_ONCE(ctx->buf_data); 997 998 ctx->buf_data = data; 999 if (ret) 1000 __io_sqe_buffers_unregister(ctx); 1001 return ret; 1002 } 1003 1004 int io_import_fixed(int ddir, struct iov_iter *iter, 1005 struct io_mapped_ubuf *imu, 1006 u64 buf_addr, size_t len) 1007 { 1008 u64 buf_end; 1009 size_t offset; 1010 1011 if (WARN_ON_ONCE(!imu)) 1012 return -EFAULT; 1013 if (unlikely(check_add_overflow(buf_addr, (u64)len, &buf_end))) 1014 return -EFAULT; 1015 /* not inside the mapped region */ 1016 if (unlikely(buf_addr < imu->ubuf || buf_end > imu->ubuf_end)) 1017 return -EFAULT; 1018 1019 /* 1020 * Might not be a start of buffer, set size appropriately 1021 * and advance us to the beginning. 1022 */ 1023 offset = buf_addr - imu->ubuf; 1024 iov_iter_bvec(iter, ddir, imu->bvec, imu->nr_bvecs, offset + len); 1025 1026 if (offset) { 1027 /* 1028 * Don't use iov_iter_advance() here, as it's really slow for 1029 * using the latter parts of a big fixed buffer - it iterates 1030 * over each segment manually. We can cheat a bit here, because 1031 * we know that: 1032 * 1033 * 1) it's a BVEC iter, we set it up 1034 * 2) all bvecs are PAGE_SIZE in size, except potentially the 1035 * first and last bvec 1036 * 1037 * So just find our index, and adjust the iterator afterwards. 1038 * If the offset is within the first bvec (or the whole first 1039 * bvec, just use iov_iter_advance(). This makes it easier 1040 * since we can just skip the first segment, which may not 1041 * be PAGE_SIZE aligned. 1042 */ 1043 const struct bio_vec *bvec = imu->bvec; 1044 1045 if (offset < bvec->bv_len) { 1046 /* 1047 * Note, huge pages buffers consists of one large 1048 * bvec entry and should always go this way. The other 1049 * branch doesn't expect non PAGE_SIZE'd chunks. 1050 */ 1051 iter->bvec = bvec; 1052 iter->count -= offset; 1053 iter->iov_offset = offset; 1054 } else { 1055 unsigned long seg_skip; 1056 1057 /* skip first vec */ 1058 offset -= bvec->bv_len; 1059 seg_skip = 1 + (offset >> PAGE_SHIFT); 1060 1061 iter->bvec = bvec + seg_skip; 1062 iter->nr_segs -= seg_skip; 1063 iter->count -= bvec->bv_len + offset; 1064 iter->iov_offset = offset & ~PAGE_MASK; 1065 } 1066 } 1067 1068 return 0; 1069 } 1070