1 // SPDX-License-Identifier: GPL-2.0-only
3 * Copyright (C) 1991, 1992 Linus Torvalds
4 * Copyright (C) 2001 Andrea Arcangeli <andrea@suse.de> SuSE
5 * Copyright (C) 2016 - 2020 Christoph Hellwig
7 #include <linux/init.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>
18 #include <linux/iomap.h>
19 #include <linux/module.h>
22 static inline struct inode *bdev_file_inode(struct file *file)
24 return file->f_mapping->host;
27 static blk_opf_t dio_bio_write_op(struct kiocb *iocb)
29 blk_opf_t opf = REQ_OP_WRITE | REQ_SYNC | REQ_IDLE;
31 /* avoid the need for a I/O completion work item */
32 if (iocb_is_dsync(iocb))
37 static bool blkdev_dio_unaligned(struct block_device *bdev, loff_t pos,
38 struct iov_iter *iter)
40 return pos & (bdev_logical_block_size(bdev) - 1) ||
41 !bdev_iter_is_aligned(bdev, iter);
44 #define DIO_INLINE_BIO_VECS 4
46 static ssize_t __blkdev_direct_IO_simple(struct kiocb *iocb,
47 struct iov_iter *iter, unsigned int nr_pages)
49 struct block_device *bdev = I_BDEV(iocb->ki_filp->f_mapping->host);
50 struct bio_vec inline_vecs[DIO_INLINE_BIO_VECS], *vecs;
51 loff_t pos = iocb->ki_pos;
52 bool should_dirty = false;
56 if (blkdev_dio_unaligned(bdev, pos, iter))
59 if (nr_pages <= DIO_INLINE_BIO_VECS)
62 vecs = kmalloc_array(nr_pages, sizeof(struct bio_vec),
68 if (iov_iter_rw(iter) == READ) {
69 bio_init(&bio, bdev, vecs, nr_pages, REQ_OP_READ);
70 if (user_backed_iter(iter))
73 bio_init(&bio, bdev, vecs, nr_pages, dio_bio_write_op(iocb));
75 bio.bi_iter.bi_sector = pos >> SECTOR_SHIFT;
76 bio.bi_write_hint = file_inode(iocb->ki_filp)->i_write_hint;
77 bio.bi_ioprio = iocb->ki_ioprio;
79 ret = bio_iov_iter_get_pages(&bio, iter);
82 ret = bio.bi_iter.bi_size;
84 if (iov_iter_rw(iter) == WRITE)
85 task_io_account_write(ret);
87 if (iocb->ki_flags & IOCB_NOWAIT)
88 bio.bi_opf |= REQ_NOWAIT;
90 submit_bio_wait(&bio);
92 bio_release_pages(&bio, should_dirty);
93 if (unlikely(bio.bi_status))
94 ret = blk_status_to_errno(bio.bi_status);
97 if (vecs != inline_vecs)
106 DIO_SHOULD_DIRTY = 1,
113 struct task_struct *waiter;
118 struct bio bio ____cacheline_aligned_in_smp;
121 static struct bio_set blkdev_dio_pool;
123 static void blkdev_bio_end_io(struct bio *bio)
125 struct blkdev_dio *dio = bio->bi_private;
126 bool should_dirty = dio->flags & DIO_SHOULD_DIRTY;
128 if (bio->bi_status && !dio->bio.bi_status)
129 dio->bio.bi_status = bio->bi_status;
131 if (atomic_dec_and_test(&dio->ref)) {
132 if (!(dio->flags & DIO_IS_SYNC)) {
133 struct kiocb *iocb = dio->iocb;
136 WRITE_ONCE(iocb->private, NULL);
138 if (likely(!dio->bio.bi_status)) {
142 ret = blk_status_to_errno(dio->bio.bi_status);
145 dio->iocb->ki_complete(iocb, ret);
148 struct task_struct *waiter = dio->waiter;
150 WRITE_ONCE(dio->waiter, NULL);
151 blk_wake_io_task(waiter);
156 bio_check_pages_dirty(bio);
158 bio_release_pages(bio, false);
163 static ssize_t __blkdev_direct_IO(struct kiocb *iocb, struct iov_iter *iter,
164 unsigned int nr_pages)
166 struct block_device *bdev = I_BDEV(iocb->ki_filp->f_mapping->host);
167 struct blk_plug plug;
168 struct blkdev_dio *dio;
170 bool is_read = (iov_iter_rw(iter) == READ), is_sync;
171 blk_opf_t opf = is_read ? REQ_OP_READ : dio_bio_write_op(iocb);
172 loff_t pos = iocb->ki_pos;
175 if (blkdev_dio_unaligned(bdev, pos, iter))
178 if (iocb->ki_flags & IOCB_ALLOC_CACHE)
179 opf |= REQ_ALLOC_CACHE;
180 bio = bio_alloc_bioset(bdev, nr_pages, opf, GFP_KERNEL,
182 dio = container_of(bio, struct blkdev_dio, bio);
183 atomic_set(&dio->ref, 1);
185 * Grab an extra reference to ensure the dio structure which is embedded
186 * into the first bio stays around.
190 is_sync = is_sync_kiocb(iocb);
192 dio->flags = DIO_IS_SYNC;
193 dio->waiter = current;
200 if (is_read && user_backed_iter(iter))
201 dio->flags |= DIO_SHOULD_DIRTY;
203 blk_start_plug(&plug);
206 bio->bi_iter.bi_sector = pos >> SECTOR_SHIFT;
207 bio->bi_write_hint = file_inode(iocb->ki_filp)->i_write_hint;
208 bio->bi_private = dio;
209 bio->bi_end_io = blkdev_bio_end_io;
210 bio->bi_ioprio = iocb->ki_ioprio;
212 ret = bio_iov_iter_get_pages(bio, iter);
214 bio->bi_status = BLK_STS_IOERR;
218 if (iocb->ki_flags & IOCB_NOWAIT) {
220 * This is nonblocking IO, and we need to allocate
221 * another bio if we have data left to map. As we
222 * cannot guarantee that one of the sub bios will not
223 * fail getting issued FOR NOWAIT and as error results
224 * are coalesced across all of them, be safe and ask for
225 * a retry of this from blocking context.
227 if (unlikely(iov_iter_count(iter))) {
228 bio_release_pages(bio, false);
229 bio_clear_flag(bio, BIO_REFFED);
231 blk_finish_plug(&plug);
234 bio->bi_opf |= REQ_NOWAIT;
238 if (dio->flags & DIO_SHOULD_DIRTY)
239 bio_set_pages_dirty(bio);
241 task_io_account_write(bio->bi_iter.bi_size);
243 dio->size += bio->bi_iter.bi_size;
244 pos += bio->bi_iter.bi_size;
246 nr_pages = bio_iov_vecs_to_alloc(iter, BIO_MAX_VECS);
251 atomic_inc(&dio->ref);
253 bio = bio_alloc(bdev, nr_pages, opf, GFP_KERNEL);
256 blk_finish_plug(&plug);
262 set_current_state(TASK_UNINTERRUPTIBLE);
263 if (!READ_ONCE(dio->waiter))
267 __set_current_state(TASK_RUNNING);
270 ret = blk_status_to_errno(dio->bio.bi_status);
278 static void blkdev_bio_end_io_async(struct bio *bio)
280 struct blkdev_dio *dio = container_of(bio, struct blkdev_dio, bio);
281 struct kiocb *iocb = dio->iocb;
284 WRITE_ONCE(iocb->private, NULL);
286 if (likely(!bio->bi_status)) {
290 ret = blk_status_to_errno(bio->bi_status);
293 iocb->ki_complete(iocb, ret);
295 if (dio->flags & DIO_SHOULD_DIRTY) {
296 bio_check_pages_dirty(bio);
298 bio_release_pages(bio, false);
303 static ssize_t __blkdev_direct_IO_async(struct kiocb *iocb,
304 struct iov_iter *iter,
305 unsigned int nr_pages)
307 struct block_device *bdev = I_BDEV(iocb->ki_filp->f_mapping->host);
308 bool is_read = iov_iter_rw(iter) == READ;
309 blk_opf_t opf = is_read ? REQ_OP_READ : dio_bio_write_op(iocb);
310 struct blkdev_dio *dio;
312 loff_t pos = iocb->ki_pos;
315 if (blkdev_dio_unaligned(bdev, pos, iter))
318 if (iocb->ki_flags & IOCB_ALLOC_CACHE)
319 opf |= REQ_ALLOC_CACHE;
320 bio = bio_alloc_bioset(bdev, nr_pages, opf, GFP_KERNEL,
322 dio = container_of(bio, struct blkdev_dio, bio);
325 bio->bi_iter.bi_sector = pos >> SECTOR_SHIFT;
326 bio->bi_write_hint = file_inode(iocb->ki_filp)->i_write_hint;
327 bio->bi_end_io = blkdev_bio_end_io_async;
328 bio->bi_ioprio = iocb->ki_ioprio;
330 if (iov_iter_is_bvec(iter)) {
332 * Users don't rely on the iterator being in any particular
333 * state for async I/O returning -EIOCBQUEUED, hence we can
334 * avoid expensive iov_iter_advance(). Bypass
335 * bio_iov_iter_get_pages() and set the bvec directly.
337 bio_iov_bvec_set(bio, iter);
339 ret = bio_iov_iter_get_pages(bio, iter);
345 dio->size = bio->bi_iter.bi_size;
348 if (user_backed_iter(iter)) {
349 dio->flags |= DIO_SHOULD_DIRTY;
350 bio_set_pages_dirty(bio);
353 task_io_account_write(bio->bi_iter.bi_size);
356 if (iocb->ki_flags & IOCB_NOWAIT)
357 bio->bi_opf |= REQ_NOWAIT;
359 if (iocb->ki_flags & IOCB_HIPRI) {
360 bio->bi_opf |= REQ_POLLED;
362 WRITE_ONCE(iocb->private, bio);
369 static ssize_t blkdev_direct_IO(struct kiocb *iocb, struct iov_iter *iter)
371 unsigned int nr_pages;
373 if (!iov_iter_count(iter))
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);
382 return __blkdev_direct_IO(iocb, iter, bio_max_segs(nr_pages));
385 static int blkdev_iomap_begin(struct inode *inode, loff_t offset, loff_t length,
386 unsigned int flags, struct iomap *iomap, struct iomap *srcmap)
388 struct block_device *bdev = I_BDEV(inode);
389 loff_t isize = i_size_read(inode);
392 iomap->offset = ALIGN_DOWN(offset, bdev_logical_block_size(bdev));
393 if (iomap->offset >= isize)
395 iomap->type = IOMAP_MAPPED;
396 iomap->addr = iomap->offset;
397 iomap->length = isize - iomap->offset;
398 iomap->flags |= IOMAP_F_BUFFER_HEAD; /* noop for !CONFIG_BUFFER_HEAD */
402 static const struct iomap_ops blkdev_iomap_ops = {
403 .iomap_begin = blkdev_iomap_begin,
406 #ifdef CONFIG_BUFFER_HEAD
407 static int blkdev_get_block(struct inode *inode, sector_t iblock,
408 struct buffer_head *bh, int create)
410 bh->b_bdev = I_BDEV(inode);
411 bh->b_blocknr = iblock;
412 set_buffer_mapped(bh);
417 * We cannot call mpage_writepages() as it does not take the buffer lock.
418 * We must use block_write_full_folio() directly which holds the buffer
419 * lock. The buffer lock provides the synchronisation with writeback
420 * that filesystems rely on when they use the blockdev's mapping.
422 static int blkdev_writepages(struct address_space *mapping,
423 struct writeback_control *wbc)
425 struct blk_plug plug;
428 blk_start_plug(&plug);
429 err = write_cache_pages(mapping, wbc, block_write_full_folio,
431 blk_finish_plug(&plug);
436 static int blkdev_read_folio(struct file *file, struct folio *folio)
438 return block_read_full_folio(folio, blkdev_get_block);
441 static void blkdev_readahead(struct readahead_control *rac)
443 mpage_readahead(rac, blkdev_get_block);
446 static int blkdev_write_begin(struct file *file, struct address_space *mapping,
447 loff_t pos, unsigned len, struct page **pagep, void **fsdata)
449 return block_write_begin(mapping, pos, len, pagep, blkdev_get_block);
452 static int blkdev_write_end(struct file *file, struct address_space *mapping,
453 loff_t pos, unsigned len, unsigned copied, struct page *page,
457 ret = block_write_end(file, mapping, pos, len, copied, page, fsdata);
465 const struct address_space_operations def_blk_aops = {
466 .dirty_folio = block_dirty_folio,
467 .invalidate_folio = block_invalidate_folio,
468 .read_folio = blkdev_read_folio,
469 .readahead = blkdev_readahead,
470 .writepages = blkdev_writepages,
471 .write_begin = blkdev_write_begin,
472 .write_end = blkdev_write_end,
473 .migrate_folio = buffer_migrate_folio_norefs,
474 .is_dirty_writeback = buffer_check_dirty_writeback,
476 #else /* CONFIG_BUFFER_HEAD */
477 static int blkdev_read_folio(struct file *file, struct folio *folio)
479 return iomap_read_folio(folio, &blkdev_iomap_ops);
482 static void blkdev_readahead(struct readahead_control *rac)
484 iomap_readahead(rac, &blkdev_iomap_ops);
487 static int blkdev_map_blocks(struct iomap_writepage_ctx *wpc,
488 struct inode *inode, loff_t offset)
490 loff_t isize = i_size_read(inode);
492 if (WARN_ON_ONCE(offset >= isize))
494 if (offset >= wpc->iomap.offset &&
495 offset < wpc->iomap.offset + wpc->iomap.length)
497 return blkdev_iomap_begin(inode, offset, isize - offset,
498 IOMAP_WRITE, &wpc->iomap, NULL);
501 static const struct iomap_writeback_ops blkdev_writeback_ops = {
502 .map_blocks = blkdev_map_blocks,
505 static int blkdev_writepages(struct address_space *mapping,
506 struct writeback_control *wbc)
508 struct iomap_writepage_ctx wpc = { };
510 return iomap_writepages(mapping, wbc, &wpc, &blkdev_writeback_ops);
513 const struct address_space_operations def_blk_aops = {
514 .dirty_folio = filemap_dirty_folio,
515 .release_folio = iomap_release_folio,
516 .invalidate_folio = iomap_invalidate_folio,
517 .read_folio = blkdev_read_folio,
518 .readahead = blkdev_readahead,
519 .writepages = blkdev_writepages,
520 .is_partially_uptodate = iomap_is_partially_uptodate,
521 .error_remove_folio = generic_error_remove_folio,
522 .migrate_folio = filemap_migrate_folio,
524 #endif /* CONFIG_BUFFER_HEAD */
527 * for a block special file file_inode(file)->i_size is zero
528 * so we compute the size by hand (just as in block_read/write above)
530 static loff_t blkdev_llseek(struct file *file, loff_t offset, int whence)
532 struct inode *bd_inode = bdev_file_inode(file);
535 inode_lock(bd_inode);
536 retval = fixed_size_llseek(file, offset, whence, i_size_read(bd_inode));
537 inode_unlock(bd_inode);
541 static int blkdev_fsync(struct file *filp, loff_t start, loff_t end,
544 struct block_device *bdev = I_BDEV(filp->f_mapping->host);
547 error = file_write_and_wait_range(filp, start, end);
552 * There is no need to serialise calls to blkdev_issue_flush with
553 * i_mutex and doing so causes performance issues with concurrent
554 * O_SYNC writers to a block device.
556 error = blkdev_issue_flush(bdev);
557 if (error == -EOPNOTSUPP)
564 * file_to_blk_mode - get block open flags from file flags
565 * @file: file whose open flags should be converted
567 * Look at file open flags and generate corresponding block open flags from
568 * them. The function works both for file just being open (e.g. during ->open
569 * callback) and for file that is already open. This is actually non-trivial
570 * (see comment in the function).
572 blk_mode_t file_to_blk_mode(struct file *file)
575 struct bdev_handle *handle = file->private_data;
577 if (file->f_mode & FMODE_READ)
578 mode |= BLK_OPEN_READ;
579 if (file->f_mode & FMODE_WRITE)
580 mode |= BLK_OPEN_WRITE;
582 * do_dentry_open() clears O_EXCL from f_flags, use handle->mode to
583 * determine whether the open was exclusive for already open files.
586 mode |= handle->mode & BLK_OPEN_EXCL;
587 else if (file->f_flags & O_EXCL)
588 mode |= BLK_OPEN_EXCL;
589 if (file->f_flags & O_NDELAY)
590 mode |= BLK_OPEN_NDELAY;
593 * If all bits in O_ACCMODE set (aka O_RDWR | O_WRONLY), the floppy
594 * driver has historically allowed ioctls as if the file was opened for
595 * writing, but does not allow and actual reads or writes.
597 if ((file->f_flags & O_ACCMODE) == (O_RDWR | O_WRONLY))
598 mode |= BLK_OPEN_WRITE_IOCTL;
603 static int blkdev_open(struct inode *inode, struct file *filp)
605 struct bdev_handle *handle;
609 * Preserve backwards compatibility and allow large file access
610 * even if userspace doesn't ask for it explicitly. Some mkfs
611 * binary needs it. We might want to drop this workaround
612 * during an unstable branch.
614 filp->f_flags |= O_LARGEFILE;
615 filp->f_mode |= FMODE_BUF_RASYNC | FMODE_CAN_ODIRECT;
617 mode = file_to_blk_mode(filp);
618 handle = bdev_open_by_dev(inode->i_rdev, mode,
619 mode & BLK_OPEN_EXCL ? filp : NULL, NULL);
621 return PTR_ERR(handle);
623 if (bdev_nowait(handle->bdev))
624 filp->f_mode |= FMODE_NOWAIT;
626 filp->f_mapping = handle->bdev->bd_inode->i_mapping;
627 filp->f_wb_err = filemap_sample_wb_err(filp->f_mapping);
628 filp->private_data = handle;
632 static int blkdev_release(struct inode *inode, struct file *filp)
634 bdev_release(filp->private_data);
639 blkdev_direct_write(struct kiocb *iocb, struct iov_iter *from)
641 size_t count = iov_iter_count(from);
644 written = kiocb_invalidate_pages(iocb, count);
646 if (written == -EBUSY)
651 written = blkdev_direct_IO(iocb, from);
653 kiocb_invalidate_post_direct_write(iocb, count);
654 iocb->ki_pos += written;
657 if (written != -EIOCBQUEUED)
658 iov_iter_revert(from, count - iov_iter_count(from));
662 static ssize_t blkdev_buffered_write(struct kiocb *iocb, struct iov_iter *from)
664 return iomap_file_buffered_write(iocb, from, &blkdev_iomap_ops);
668 * Write data to the block device. Only intended for the block device itself
669 * and the raw driver which basically is a fake block device.
671 * Does not take i_mutex for the write and thus is not for general purpose
674 static ssize_t blkdev_write_iter(struct kiocb *iocb, struct iov_iter *from)
676 struct file *file = iocb->ki_filp;
677 struct block_device *bdev = I_BDEV(file->f_mapping->host);
678 struct inode *bd_inode = bdev->bd_inode;
679 loff_t size = bdev_nr_bytes(bdev);
683 if (bdev_read_only(bdev))
686 if (IS_SWAPFILE(bd_inode) && !is_hibernate_resume_dev(bd_inode->i_rdev))
689 if (!iov_iter_count(from))
692 if (iocb->ki_pos >= size)
695 if ((iocb->ki_flags & (IOCB_NOWAIT | IOCB_DIRECT)) == IOCB_NOWAIT)
698 size -= iocb->ki_pos;
699 if (iov_iter_count(from) > size) {
700 shorted = iov_iter_count(from) - size;
701 iov_iter_truncate(from, size);
704 ret = file_update_time(file);
708 if (iocb->ki_flags & IOCB_DIRECT) {
709 ret = blkdev_direct_write(iocb, from);
710 if (ret >= 0 && iov_iter_count(from))
711 ret = direct_write_fallback(iocb, from, ret,
712 blkdev_buffered_write(iocb, from));
714 ret = blkdev_buffered_write(iocb, from);
718 ret = generic_write_sync(iocb, ret);
719 iov_iter_reexpand(from, iov_iter_count(from) + shorted);
723 static ssize_t blkdev_read_iter(struct kiocb *iocb, struct iov_iter *to)
725 struct block_device *bdev = I_BDEV(iocb->ki_filp->f_mapping->host);
726 loff_t size = bdev_nr_bytes(bdev);
727 loff_t pos = iocb->ki_pos;
732 if (unlikely(pos + iov_iter_count(to) > size)) {
736 shorted = iov_iter_count(to) - size;
737 iov_iter_truncate(to, size);
740 count = iov_iter_count(to);
742 goto reexpand; /* skip atime */
744 if (iocb->ki_flags & IOCB_DIRECT) {
745 ret = kiocb_write_and_wait(iocb, count);
748 file_accessed(iocb->ki_filp);
750 ret = blkdev_direct_IO(iocb, to);
755 iov_iter_revert(to, count - iov_iter_count(to));
756 if (ret < 0 || !count)
760 ret = filemap_read(iocb, to, ret);
763 if (unlikely(shorted))
764 iov_iter_reexpand(to, iov_iter_count(to) + shorted);
768 #define BLKDEV_FALLOC_FL_SUPPORTED \
769 (FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE | \
770 FALLOC_FL_ZERO_RANGE | FALLOC_FL_NO_HIDE_STALE)
772 static long blkdev_fallocate(struct file *file, int mode, loff_t start,
775 struct inode *inode = bdev_file_inode(file);
776 struct block_device *bdev = I_BDEV(inode);
777 loff_t end = start + len - 1;
781 /* Fail if we don't recognize the flags. */
782 if (mode & ~BLKDEV_FALLOC_FL_SUPPORTED)
785 /* Don't go off the end of the device. */
786 isize = bdev_nr_bytes(bdev);
790 if (mode & FALLOC_FL_KEEP_SIZE) {
792 end = start + len - 1;
798 * Don't allow IO that isn't aligned to logical block size.
800 if ((start | len) & (bdev_logical_block_size(bdev) - 1))
803 filemap_invalidate_lock(inode->i_mapping);
806 * Invalidate the page cache, including dirty pages, for valid
807 * de-allocate mode calls to fallocate().
810 case FALLOC_FL_ZERO_RANGE:
811 case FALLOC_FL_ZERO_RANGE | FALLOC_FL_KEEP_SIZE:
812 error = truncate_bdev_range(bdev, file_to_blk_mode(file), start, end);
816 error = blkdev_issue_zeroout(bdev, start >> SECTOR_SHIFT,
817 len >> SECTOR_SHIFT, GFP_KERNEL,
818 BLKDEV_ZERO_NOUNMAP);
820 case FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE:
821 error = truncate_bdev_range(bdev, file_to_blk_mode(file), start, end);
825 error = blkdev_issue_zeroout(bdev, start >> SECTOR_SHIFT,
826 len >> SECTOR_SHIFT, GFP_KERNEL,
827 BLKDEV_ZERO_NOFALLBACK);
829 case FALLOC_FL_PUNCH_HOLE | FALLOC_FL_KEEP_SIZE | FALLOC_FL_NO_HIDE_STALE:
830 error = truncate_bdev_range(bdev, file_to_blk_mode(file), start, end);
834 error = blkdev_issue_discard(bdev, start >> SECTOR_SHIFT,
835 len >> SECTOR_SHIFT, GFP_KERNEL);
842 filemap_invalidate_unlock(inode->i_mapping);
846 static int blkdev_mmap(struct file *file, struct vm_area_struct *vma)
848 struct inode *bd_inode = bdev_file_inode(file);
850 if (bdev_read_only(I_BDEV(bd_inode)))
851 return generic_file_readonly_mmap(file, vma);
853 return generic_file_mmap(file, vma);
856 const struct file_operations def_blk_fops = {
858 .release = blkdev_release,
859 .llseek = blkdev_llseek,
860 .read_iter = blkdev_read_iter,
861 .write_iter = blkdev_write_iter,
862 .iopoll = iocb_bio_iopoll,
864 .fsync = blkdev_fsync,
865 .unlocked_ioctl = blkdev_ioctl,
867 .compat_ioctl = compat_blkdev_ioctl,
869 .splice_read = filemap_splice_read,
870 .splice_write = iter_file_splice_write,
871 .fallocate = blkdev_fallocate,
874 static __init int blkdev_init(void)
876 return bioset_init(&blkdev_dio_pool, 4,
877 offsetof(struct blkdev_dio, bio),
878 BIOSET_NEED_BVECS|BIOSET_PERCPU_CACHE);
880 module_init(blkdev_init);