1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * Copyright (C) 1991, 1992 Linus Torvalds 4 * Copyright (C) 2001 Andrea Arcangeli <andrea@suse.de> SuSE 5 * Copyright (C) 2016 - 2020 Christoph Hellwig 6 */ 7 #include <linux/init.h> 8 #include <linux/mm.h> 9 #include <linux/blkdev.h> 10 #include <linux/buffer_head.h> 11 #include <linux/mpage.h> 12 #include <linux/uio.h> 13 #include <linux/namei.h> 14 #include <linux/task_io_accounting_ops.h> 15 #include <linux/falloc.h> 16 #include <linux/suspend.h> 17 #include <linux/fs.h> 18 #include <linux/module.h> 19 #include "blk.h" 20 21 static inline struct inode *bdev_file_inode(struct file *file) 22 { 23 return file->f_mapping->host; 24 } 25 26 static int blkdev_get_block(struct inode *inode, sector_t iblock, 27 struct buffer_head *bh, int create) 28 { 29 bh->b_bdev = I_BDEV(inode); 30 bh->b_blocknr = iblock; 31 set_buffer_mapped(bh); 32 return 0; 33 } 34 35 static unsigned int dio_bio_write_op(struct kiocb *iocb) 36 { 37 unsigned int op = REQ_OP_WRITE | REQ_SYNC | REQ_IDLE; 38 39 /* avoid the need for a I/O completion work item */ 40 if (iocb->ki_flags & IOCB_DSYNC) 41 op |= REQ_FUA; 42 return op; 43 } 44 45 #define DIO_INLINE_BIO_VECS 4 46 47 static void blkdev_bio_end_io_simple(struct bio *bio) 48 { 49 struct task_struct *waiter = bio->bi_private; 50 51 WRITE_ONCE(bio->bi_private, NULL); 52 blk_wake_io_task(waiter); 53 } 54 55 static ssize_t __blkdev_direct_IO_simple(struct kiocb *iocb, 56 struct iov_iter *iter, unsigned int nr_pages) 57 { 58 struct block_device *bdev = iocb->ki_filp->private_data; 59 struct bio_vec inline_vecs[DIO_INLINE_BIO_VECS], *vecs; 60 loff_t pos = iocb->ki_pos; 61 bool should_dirty = false; 62 struct bio bio; 63 ssize_t ret; 64 65 if ((pos | iov_iter_alignment(iter)) & 66 (bdev_logical_block_size(bdev) - 1)) 67 return -EINVAL; 68 69 if (nr_pages <= DIO_INLINE_BIO_VECS) 70 vecs = inline_vecs; 71 else { 72 vecs = kmalloc_array(nr_pages, sizeof(struct bio_vec), 73 GFP_KERNEL); 74 if (!vecs) 75 return -ENOMEM; 76 } 77 78 if (iov_iter_rw(iter) == READ) { 79 bio_init(&bio, bdev, vecs, nr_pages, REQ_OP_READ); 80 if (iter_is_iovec(iter)) 81 should_dirty = true; 82 } else { 83 bio_init(&bio, bdev, vecs, nr_pages, dio_bio_write_op(iocb)); 84 } 85 bio.bi_iter.bi_sector = pos >> SECTOR_SHIFT; 86 bio.bi_private = current; 87 bio.bi_end_io = blkdev_bio_end_io_simple; 88 bio.bi_ioprio = iocb->ki_ioprio; 89 90 ret = bio_iov_iter_get_pages(&bio, iter); 91 if (unlikely(ret)) 92 goto out; 93 ret = bio.bi_iter.bi_size; 94 95 if (iov_iter_rw(iter) == WRITE) 96 task_io_account_write(ret); 97 98 if (iocb->ki_flags & IOCB_NOWAIT) 99 bio.bi_opf |= REQ_NOWAIT; 100 if (iocb->ki_flags & IOCB_HIPRI) 101 bio_set_polled(&bio, iocb); 102 103 submit_bio(&bio); 104 for (;;) { 105 set_current_state(TASK_UNINTERRUPTIBLE); 106 if (!READ_ONCE(bio.bi_private)) 107 break; 108 if (!(iocb->ki_flags & IOCB_HIPRI) || !bio_poll(&bio, NULL, 0)) 109 blk_io_schedule(); 110 } 111 __set_current_state(TASK_RUNNING); 112 113 bio_release_pages(&bio, should_dirty); 114 if (unlikely(bio.bi_status)) 115 ret = blk_status_to_errno(bio.bi_status); 116 117 out: 118 if (vecs != inline_vecs) 119 kfree(vecs); 120 121 bio_uninit(&bio); 122 123 return ret; 124 } 125 126 enum { 127 DIO_SHOULD_DIRTY = 1, 128 DIO_IS_SYNC = 2, 129 }; 130 131 struct blkdev_dio { 132 union { 133 struct kiocb *iocb; 134 struct task_struct *waiter; 135 }; 136 size_t size; 137 atomic_t ref; 138 unsigned int flags; 139 struct bio bio ____cacheline_aligned_in_smp; 140 }; 141 142 static struct bio_set blkdev_dio_pool; 143 144 static void blkdev_bio_end_io(struct bio *bio) 145 { 146 struct blkdev_dio *dio = bio->bi_private; 147 bool should_dirty = dio->flags & DIO_SHOULD_DIRTY; 148 149 if (bio->bi_status && !dio->bio.bi_status) 150 dio->bio.bi_status = bio->bi_status; 151 152 if (atomic_dec_and_test(&dio->ref)) { 153 if (!(dio->flags & DIO_IS_SYNC)) { 154 struct kiocb *iocb = dio->iocb; 155 ssize_t ret; 156 157 WRITE_ONCE(iocb->private, NULL); 158 159 if (likely(!dio->bio.bi_status)) { 160 ret = dio->size; 161 iocb->ki_pos += ret; 162 } else { 163 ret = blk_status_to_errno(dio->bio.bi_status); 164 } 165 166 dio->iocb->ki_complete(iocb, ret); 167 bio_put(&dio->bio); 168 } else { 169 struct task_struct *waiter = dio->waiter; 170 171 WRITE_ONCE(dio->waiter, NULL); 172 blk_wake_io_task(waiter); 173 } 174 } 175 176 if (should_dirty) { 177 bio_check_pages_dirty(bio); 178 } else { 179 bio_release_pages(bio, false); 180 bio_put(bio); 181 } 182 } 183 184 static ssize_t __blkdev_direct_IO(struct kiocb *iocb, struct iov_iter *iter, 185 unsigned int nr_pages) 186 { 187 struct block_device *bdev = iocb->ki_filp->private_data; 188 struct blk_plug plug; 189 struct blkdev_dio *dio; 190 struct bio *bio; 191 bool is_read = (iov_iter_rw(iter) == READ), is_sync; 192 unsigned int opf = is_read ? REQ_OP_READ : dio_bio_write_op(iocb); 193 loff_t pos = iocb->ki_pos; 194 int ret = 0; 195 196 if ((pos | iov_iter_alignment(iter)) & 197 (bdev_logical_block_size(bdev) - 1)) 198 return -EINVAL; 199 200 bio = bio_alloc_kiocb(iocb, bdev, nr_pages, opf, &blkdev_dio_pool); 201 202 dio = container_of(bio, struct blkdev_dio, bio); 203 atomic_set(&dio->ref, 1); 204 /* 205 * Grab an extra reference to ensure the dio structure which is embedded 206 * into the first bio stays around. 207 */ 208 bio_get(bio); 209 210 is_sync = is_sync_kiocb(iocb); 211 if (is_sync) { 212 dio->flags = DIO_IS_SYNC; 213 dio->waiter = current; 214 } else { 215 dio->flags = 0; 216 dio->iocb = iocb; 217 } 218 219 dio->size = 0; 220 if (is_read && iter_is_iovec(iter)) 221 dio->flags |= DIO_SHOULD_DIRTY; 222 223 blk_start_plug(&plug); 224 225 for (;;) { 226 bio->bi_iter.bi_sector = pos >> SECTOR_SHIFT; 227 bio->bi_private = dio; 228 bio->bi_end_io = blkdev_bio_end_io; 229 bio->bi_ioprio = iocb->ki_ioprio; 230 231 ret = bio_iov_iter_get_pages(bio, iter); 232 if (unlikely(ret)) { 233 bio->bi_status = BLK_STS_IOERR; 234 bio_endio(bio); 235 break; 236 } 237 238 if (is_read) { 239 if (dio->flags & DIO_SHOULD_DIRTY) 240 bio_set_pages_dirty(bio); 241 } else { 242 task_io_account_write(bio->bi_iter.bi_size); 243 } 244 if (iocb->ki_flags & IOCB_NOWAIT) 245 bio->bi_opf |= REQ_NOWAIT; 246 247 dio->size += bio->bi_iter.bi_size; 248 pos += bio->bi_iter.bi_size; 249 250 nr_pages = bio_iov_vecs_to_alloc(iter, BIO_MAX_VECS); 251 if (!nr_pages) { 252 submit_bio(bio); 253 break; 254 } 255 atomic_inc(&dio->ref); 256 submit_bio(bio); 257 bio = bio_alloc(bdev, nr_pages, opf, GFP_KERNEL); 258 } 259 260 blk_finish_plug(&plug); 261 262 if (!is_sync) 263 return -EIOCBQUEUED; 264 265 for (;;) { 266 set_current_state(TASK_UNINTERRUPTIBLE); 267 if (!READ_ONCE(dio->waiter)) 268 break; 269 blk_io_schedule(); 270 } 271 __set_current_state(TASK_RUNNING); 272 273 if (!ret) 274 ret = blk_status_to_errno(dio->bio.bi_status); 275 if (likely(!ret)) 276 ret = dio->size; 277 278 bio_put(&dio->bio); 279 return ret; 280 } 281 282 static void blkdev_bio_end_io_async(struct bio *bio) 283 { 284 struct blkdev_dio *dio = container_of(bio, struct blkdev_dio, bio); 285 struct kiocb *iocb = dio->iocb; 286 ssize_t ret; 287 288 WRITE_ONCE(iocb->private, NULL); 289 290 if (likely(!bio->bi_status)) { 291 ret = dio->size; 292 iocb->ki_pos += ret; 293 } else { 294 ret = blk_status_to_errno(bio->bi_status); 295 } 296 297 iocb->ki_complete(iocb, ret); 298 299 if (dio->flags & DIO_SHOULD_DIRTY) { 300 bio_check_pages_dirty(bio); 301 } else { 302 bio_release_pages(bio, false); 303 bio_put(bio); 304 } 305 } 306 307 static ssize_t __blkdev_direct_IO_async(struct kiocb *iocb, 308 struct iov_iter *iter, 309 unsigned int nr_pages) 310 { 311 struct block_device *bdev = iocb->ki_filp->private_data; 312 bool is_read = iov_iter_rw(iter) == READ; 313 unsigned int opf = is_read ? REQ_OP_READ : dio_bio_write_op(iocb); 314 struct blkdev_dio *dio; 315 struct bio *bio; 316 loff_t pos = iocb->ki_pos; 317 int ret = 0; 318 319 if ((pos | iov_iter_alignment(iter)) & 320 (bdev_logical_block_size(bdev) - 1)) 321 return -EINVAL; 322 323 bio = bio_alloc_kiocb(iocb, bdev, nr_pages, opf, &blkdev_dio_pool); 324 dio = container_of(bio, struct blkdev_dio, bio); 325 dio->flags = 0; 326 dio->iocb = iocb; 327 bio->bi_iter.bi_sector = pos >> SECTOR_SHIFT; 328 bio->bi_end_io = blkdev_bio_end_io_async; 329 bio->bi_ioprio = iocb->ki_ioprio; 330 331 if (iov_iter_is_bvec(iter)) { 332 /* 333 * Users don't rely on the iterator being in any particular 334 * state for async I/O returning -EIOCBQUEUED, hence we can 335 * avoid expensive iov_iter_advance(). Bypass 336 * bio_iov_iter_get_pages() and set the bvec directly. 337 */ 338 bio_iov_bvec_set(bio, iter); 339 } else { 340 ret = bio_iov_iter_get_pages(bio, iter); 341 if (unlikely(ret)) { 342 bio_put(bio); 343 return ret; 344 } 345 } 346 dio->size = bio->bi_iter.bi_size; 347 348 if (is_read) { 349 if (iter_is_iovec(iter)) { 350 dio->flags |= DIO_SHOULD_DIRTY; 351 bio_set_pages_dirty(bio); 352 } 353 } else { 354 task_io_account_write(bio->bi_iter.bi_size); 355 } 356 357 if (iocb->ki_flags & IOCB_HIPRI) { 358 bio->bi_opf |= REQ_POLLED | REQ_NOWAIT; 359 submit_bio(bio); 360 WRITE_ONCE(iocb->private, bio); 361 } else { 362 if (iocb->ki_flags & IOCB_NOWAIT) 363 bio->bi_opf |= REQ_NOWAIT; 364 submit_bio(bio); 365 } 366 return -EIOCBQUEUED; 367 } 368 369 static ssize_t blkdev_direct_IO(struct kiocb *iocb, struct iov_iter *iter) 370 { 371 unsigned int nr_pages; 372 373 if (!iov_iter_count(iter)) 374 return 0; 375 376 nr_pages = bio_iov_vecs_to_alloc(iter, BIO_MAX_VECS + 1); 377 if (likely(nr_pages <= BIO_MAX_VECS)) { 378 if (is_sync_kiocb(iocb)) 379 return __blkdev_direct_IO_simple(iocb, iter, nr_pages); 380 return __blkdev_direct_IO_async(iocb, iter, nr_pages); 381 } 382 return __blkdev_direct_IO(iocb, iter, bio_max_segs(nr_pages)); 383 } 384 385 static int blkdev_writepage(struct page *page, struct writeback_control *wbc) 386 { 387 return block_write_full_page(page, blkdev_get_block, wbc); 388 } 389 390 static int blkdev_readpage(struct file * file, struct page * page) 391 { 392 return block_read_full_page(page, blkdev_get_block); 393 } 394 395 static void blkdev_readahead(struct readahead_control *rac) 396 { 397 mpage_readahead(rac, blkdev_get_block); 398 } 399 400 static int blkdev_write_begin(struct file *file, struct address_space *mapping, 401 loff_t pos, unsigned len, unsigned flags, struct page **pagep, 402 void **fsdata) 403 { 404 return block_write_begin(mapping, pos, len, flags, pagep, 405 blkdev_get_block); 406 } 407 408 static int blkdev_write_end(struct file *file, struct address_space *mapping, 409 loff_t pos, unsigned len, unsigned copied, struct page *page, 410 void *fsdata) 411 { 412 int ret; 413 ret = block_write_end(file, mapping, pos, len, copied, page, fsdata); 414 415 unlock_page(page); 416 put_page(page); 417 418 return ret; 419 } 420 421 static int blkdev_writepages(struct address_space *mapping, 422 struct writeback_control *wbc) 423 { 424 return generic_writepages(mapping, wbc); 425 } 426 427 const struct address_space_operations def_blk_aops = { 428 .dirty_folio = block_dirty_folio, 429 .invalidate_folio = block_invalidate_folio, 430 .readpage = blkdev_readpage, 431 .readahead = blkdev_readahead, 432 .writepage = blkdev_writepage, 433 .write_begin = blkdev_write_begin, 434 .write_end = blkdev_write_end, 435 .writepages = blkdev_writepages, 436 .direct_IO = blkdev_direct_IO, 437 .migratepage = buffer_migrate_page_norefs, 438 .is_dirty_writeback = buffer_check_dirty_writeback, 439 }; 440 441 /* 442 * for a block special file file_inode(file)->i_size is zero 443 * so we compute the size by hand (just as in block_read/write above) 444 */ 445 static loff_t blkdev_llseek(struct file *file, loff_t offset, int whence) 446 { 447 struct inode *bd_inode = bdev_file_inode(file); 448 loff_t retval; 449 450 inode_lock(bd_inode); 451 retval = fixed_size_llseek(file, offset, whence, i_size_read(bd_inode)); 452 inode_unlock(bd_inode); 453 return retval; 454 } 455 456 static int blkdev_fsync(struct file *filp, loff_t start, loff_t end, 457 int datasync) 458 { 459 struct block_device *bdev = filp->private_data; 460 int error; 461 462 error = file_write_and_wait_range(filp, start, end); 463 if (error) 464 return error; 465 466 /* 467 * There is no need to serialise calls to blkdev_issue_flush with 468 * i_mutex and doing so causes performance issues with concurrent 469 * O_SYNC writers to a block device. 470 */ 471 error = blkdev_issue_flush(bdev); 472 if (error == -EOPNOTSUPP) 473 error = 0; 474 475 return error; 476 } 477 478 static int blkdev_open(struct inode *inode, struct file *filp) 479 { 480 struct block_device *bdev; 481 482 /* 483 * Preserve backwards compatibility and allow large file access 484 * even if userspace doesn't ask for it explicitly. Some mkfs 485 * binary needs it. We might want to drop this workaround 486 * during an unstable branch. 487 */ 488 filp->f_flags |= O_LARGEFILE; 489 filp->f_mode |= FMODE_NOWAIT | FMODE_BUF_RASYNC; 490 491 if (filp->f_flags & O_NDELAY) 492 filp->f_mode |= FMODE_NDELAY; 493 if (filp->f_flags & O_EXCL) 494 filp->f_mode |= FMODE_EXCL; 495 if ((filp->f_flags & O_ACCMODE) == 3) 496 filp->f_mode |= FMODE_WRITE_IOCTL; 497 498 bdev = blkdev_get_by_dev(inode->i_rdev, filp->f_mode, filp); 499 if (IS_ERR(bdev)) 500 return PTR_ERR(bdev); 501 502 filp->private_data = bdev; 503 filp->f_mapping = bdev->bd_inode->i_mapping; 504 filp->f_wb_err = filemap_sample_wb_err(filp->f_mapping); 505 return 0; 506 } 507 508 static int blkdev_close(struct inode *inode, struct file *filp) 509 { 510 struct block_device *bdev = filp->private_data; 511 512 blkdev_put(bdev, filp->f_mode); 513 return 0; 514 } 515 516 /* 517 * Write data to the block device. Only intended for the block device itself 518 * and the raw driver which basically is a fake block device. 519 * 520 * Does not take i_mutex for the write and thus is not for general purpose 521 * use. 522 */ 523 static ssize_t blkdev_write_iter(struct kiocb *iocb, struct iov_iter *from) 524 { 525 struct block_device *bdev = iocb->ki_filp->private_data; 526 struct inode *bd_inode = bdev->bd_inode; 527 loff_t size = bdev_nr_bytes(bdev); 528 struct blk_plug plug; 529 size_t shorted = 0; 530 ssize_t ret; 531 532 if (bdev_read_only(bdev)) 533 return -EPERM; 534 535 if (IS_SWAPFILE(bd_inode) && !is_hibernate_resume_dev(bd_inode->i_rdev)) 536 return -ETXTBSY; 537 538 if (!iov_iter_count(from)) 539 return 0; 540 541 if (iocb->ki_pos >= size) 542 return -ENOSPC; 543 544 if ((iocb->ki_flags & (IOCB_NOWAIT | IOCB_DIRECT)) == IOCB_NOWAIT) 545 return -EOPNOTSUPP; 546 547 size -= iocb->ki_pos; 548 if (iov_iter_count(from) > size) { 549 shorted = iov_iter_count(from) - size; 550 iov_iter_truncate(from, size); 551 } 552 553 blk_start_plug(&plug); 554 ret = __generic_file_write_iter(iocb, from); 555 if (ret > 0) 556 ret = generic_write_sync(iocb, ret); 557 iov_iter_reexpand(from, iov_iter_count(from) + shorted); 558 blk_finish_plug(&plug); 559 return ret; 560 } 561 562 static ssize_t blkdev_read_iter(struct kiocb *iocb, struct iov_iter *to) 563 { 564 struct block_device *bdev = iocb->ki_filp->private_data; 565 loff_t size = bdev_nr_bytes(bdev); 566 loff_t pos = iocb->ki_pos; 567 size_t shorted = 0; 568 ssize_t ret = 0; 569 size_t count; 570 571 if (unlikely(pos + iov_iter_count(to) > size)) { 572 if (pos >= size) 573 return 0; 574 size -= pos; 575 shorted = iov_iter_count(to) - size; 576 iov_iter_truncate(to, size); 577 } 578 579 count = iov_iter_count(to); 580 if (!count) 581 goto reexpand; /* skip atime */ 582 583 if (iocb->ki_flags & IOCB_DIRECT) { 584 struct address_space *mapping = iocb->ki_filp->f_mapping; 585 586 if (iocb->ki_flags & IOCB_NOWAIT) { 587 if (filemap_range_needs_writeback(mapping, pos, 588 pos + count - 1)) { 589 ret = -EAGAIN; 590 goto reexpand; 591 } 592 } else { 593 ret = filemap_write_and_wait_range(mapping, pos, 594 pos + count - 1); 595 if (ret < 0) 596 goto reexpand; 597 } 598 599 file_accessed(iocb->ki_filp); 600 601 ret = blkdev_direct_IO(iocb, to); 602 if (ret >= 0) { 603 iocb->ki_pos += ret; 604 count -= ret; 605 } 606 iov_iter_revert(to, count - iov_iter_count(to)); 607 if (ret < 0 || !count) 608 goto reexpand; 609 } 610 611 ret = filemap_read(iocb, to, ret); 612 613 reexpand: 614 if (unlikely(shorted)) 615 iov_iter_reexpand(to, iov_iter_count(to) + shorted); 616 return ret; 617 } 618 619 #define BLKDEV_FALLOC_FL_SUPPORTED \ 620 (FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE | \ 621 FALLOC_FL_ZERO_RANGE | FALLOC_FL_NO_HIDE_STALE) 622 623 static long blkdev_fallocate(struct file *file, int mode, loff_t start, 624 loff_t len) 625 { 626 struct inode *inode = bdev_file_inode(file); 627 struct block_device *bdev = I_BDEV(inode); 628 loff_t end = start + len - 1; 629 loff_t isize; 630 int error; 631 632 /* Fail if we don't recognize the flags. */ 633 if (mode & ~BLKDEV_FALLOC_FL_SUPPORTED) 634 return -EOPNOTSUPP; 635 636 /* Don't go off the end of the device. */ 637 isize = bdev_nr_bytes(bdev); 638 if (start >= isize) 639 return -EINVAL; 640 if (end >= isize) { 641 if (mode & FALLOC_FL_KEEP_SIZE) { 642 len = isize - start; 643 end = start + len - 1; 644 } else 645 return -EINVAL; 646 } 647 648 /* 649 * Don't allow IO that isn't aligned to logical block size. 650 */ 651 if ((start | len) & (bdev_logical_block_size(bdev) - 1)) 652 return -EINVAL; 653 654 filemap_invalidate_lock(inode->i_mapping); 655 656 /* Invalidate the page cache, including dirty pages. */ 657 error = truncate_bdev_range(bdev, file->f_mode, start, end); 658 if (error) 659 goto fail; 660 661 switch (mode) { 662 case FALLOC_FL_ZERO_RANGE: 663 case FALLOC_FL_ZERO_RANGE | FALLOC_FL_KEEP_SIZE: 664 error = blkdev_issue_zeroout(bdev, start >> SECTOR_SHIFT, 665 len >> SECTOR_SHIFT, GFP_KERNEL, 666 BLKDEV_ZERO_NOUNMAP); 667 break; 668 case FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE: 669 error = blkdev_issue_zeroout(bdev, start >> SECTOR_SHIFT, 670 len >> SECTOR_SHIFT, GFP_KERNEL, 671 BLKDEV_ZERO_NOFALLBACK); 672 break; 673 case FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE | FALLOC_FL_NO_HIDE_STALE: 674 error = blkdev_issue_discard(bdev, start >> SECTOR_SHIFT, 675 len >> SECTOR_SHIFT, GFP_KERNEL, 0); 676 break; 677 default: 678 error = -EOPNOTSUPP; 679 } 680 681 fail: 682 filemap_invalidate_unlock(inode->i_mapping); 683 return error; 684 } 685 686 const struct file_operations def_blk_fops = { 687 .open = blkdev_open, 688 .release = blkdev_close, 689 .llseek = blkdev_llseek, 690 .read_iter = blkdev_read_iter, 691 .write_iter = blkdev_write_iter, 692 .iopoll = iocb_bio_iopoll, 693 .mmap = generic_file_mmap, 694 .fsync = blkdev_fsync, 695 .unlocked_ioctl = blkdev_ioctl, 696 #ifdef CONFIG_COMPAT 697 .compat_ioctl = compat_blkdev_ioctl, 698 #endif 699 .splice_read = generic_file_splice_read, 700 .splice_write = iter_file_splice_write, 701 .fallocate = blkdev_fallocate, 702 }; 703 704 static __init int blkdev_init(void) 705 { 706 return bioset_init(&blkdev_dio_pool, 4, 707 offsetof(struct blkdev_dio, bio), 708 BIOSET_NEED_BVECS|BIOSET_PERCPU_CACHE); 709 } 710 module_init(blkdev_init); 711