| Message ID | cde94f6cc32bd8a899129575678c4195f7cb187b.1610170479.git.asml.silence@gmail.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | no-copy bvec | expand |
On Sat, Jan 09, 2021 at 04:03:02PM +0000, Pavel Begunkov wrote: > 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> > --- > fs/block_dev.c | 7 ++++--- > fs/iomap/direct-io.c | 9 ++++----- > 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 1edda614f7ce..d8f9077c43ef 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); > -- > 2.24.0 > Reviewed-by: Ming Lei <ming.lei@redhat.com>
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 1edda614f7ce..d8f9077c43ef 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);