diff options
| author | Pavel Begunkov <asml.silence@gmail.com> | 2021-01-09 16:03:02 +0000 |
|---|---|---|
| committer | Jens Axboe <axboe@kernel.dk> | 2021-01-25 08:58:24 -0700 |
| commit | 3e1a88ec96259282b9a8b45c3f1fda7a3ff4f6ea (patch) | |
| tree | e650e34e08f97cadb1d47e9650ff045006bac9be | |
| parent | 54c8195b4ebe10af66b49ab9c809bc16939555fc (diff) | |
bio: add a helper calculating nr segments to alloc
Add a helper function calculating the number of bvec segments we need to
allocate to construct a bio. It doesn't change anything functionally,
but will be used to not duplicate special cases in the future.
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
| -rw-r--r-- | fs/block_dev.c | 7 | ||||
| -rw-r--r-- | fs/iomap/direct-io.c | 9 | ||||
| -rw-r--r-- | include/linux/bio.h | 10 |
3 files changed, 18 insertions, 8 deletions
diff --git a/fs/block_dev.c b/fs/block_dev.c index 3b8963e228a1..6f5bd9950baf 100644 --- a/fs/block_dev.c +++ b/fs/block_dev.c @@ -416,7 +416,7 @@ __blkdev_direct_IO(struct kiocb *iocb, struct iov_iter *iter, int nr_pages) dio->size += bio->bi_iter.bi_size; pos += bio->bi_iter.bi_size; - nr_pages = iov_iter_npages(iter, BIO_MAX_PAGES); + nr_pages = bio_iov_vecs_to_alloc(iter, BIO_MAX_PAGES); if (!nr_pages) { bool polled = false; @@ -481,9 +481,10 @@ blkdev_direct_IO(struct kiocb *iocb, struct iov_iter *iter) { int nr_pages; - nr_pages = iov_iter_npages(iter, BIO_MAX_PAGES + 1); - if (!nr_pages) + if (!iov_iter_count(iter)) return 0; + + nr_pages = bio_iov_vecs_to_alloc(iter, BIO_MAX_PAGES + 1); if (is_sync_kiocb(iocb) && nr_pages <= BIO_MAX_PAGES) return __blkdev_direct_IO_simple(iocb, iter, nr_pages); diff --git a/fs/iomap/direct-io.c b/fs/iomap/direct-io.c index 933f234d5bec..ea1e8f696076 100644 --- a/fs/iomap/direct-io.c +++ b/fs/iomap/direct-io.c @@ -250,11 +250,8 @@ iomap_dio_bio_actor(struct inode *inode, loff_t pos, loff_t length, orig_count = iov_iter_count(dio->submit.iter); iov_iter_truncate(dio->submit.iter, length); - nr_pages = iov_iter_npages(dio->submit.iter, BIO_MAX_PAGES); - if (nr_pages <= 0) { - ret = nr_pages; + if (!iov_iter_count(dio->submit.iter)) goto out; - } if (need_zeroout) { /* zero out from the start of the block to the write offset */ @@ -263,6 +260,7 @@ iomap_dio_bio_actor(struct inode *inode, loff_t pos, loff_t length, iomap_dio_zero(dio, iomap, pos - pad, pad); } + nr_pages = bio_iov_vecs_to_alloc(dio->submit.iter, BIO_MAX_PAGES); do { size_t n; if (dio->error) { @@ -308,7 +306,8 @@ iomap_dio_bio_actor(struct inode *inode, loff_t pos, loff_t length, dio->size += n; copied += n; - nr_pages = iov_iter_npages(dio->submit.iter, BIO_MAX_PAGES); + nr_pages = bio_iov_vecs_to_alloc(dio->submit.iter, + BIO_MAX_PAGES); iomap_dio_submit_bio(dio, iomap, bio, pos); pos += n; } while (nr_pages); diff --git a/include/linux/bio.h b/include/linux/bio.h index e135b500df5d..9ddb19801a03 100644 --- a/include/linux/bio.h +++ b/include/linux/bio.h @@ -10,6 +10,7 @@ #include <linux/ioprio.h> /* struct bio, bio_vec and BIO_* flags are defined in blk_types.h */ #include <linux/blk_types.h> +#include <linux/uio.h> #define BIO_DEBUG @@ -441,6 +442,15 @@ static inline void bio_wouldblock_error(struct bio *bio) bio_endio(bio); } +/* + * Calculate number of bvec segments that should be allocated to fit data + * pointed by @iter. + */ +static inline int bio_iov_vecs_to_alloc(struct iov_iter *iter, int max_segs) +{ + return iov_iter_npages(iter, max_segs); +} + struct request_queue; extern int submit_bio_wait(struct bio *bio); |