[RFC PATCH 02/34] block: introduce and use bio_new

Chaitanya Kulkarni
2021-01-28T07:59:48Z

Introduce bio_new() helper and use it in blk-lib.c to allocate and
initialize various non-optional or semi-optional members of the bio
along with bio allocation done with bio_alloc(). Here we also calmp the
max_bvecs for bio with BIO_MAX_PAGES before we pass to bio_alloc().

Signed-off-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
---
block/blk-lib.c | 6 +-----
include/linux/bio.h | 25 +++++++++++++++++++++++++
2 files changed, 26 insertions(+), 5 deletions(-)

diff --git a/block/blk-lib.c b/block/blk-lib.c
index fb486a0bdb58..ec29415f00dd 100644
--- a/block/blk-lib.c
+++ b/block/blk-lib.c
@@ -14,17 +14,13 @@ struct bio *blk_next_bio(struct bio *bio, struct block_device *bdev,
sector_t sect, unsigned op, unsigned opf,
unsigned int nr_pages, gfp_t gfp)
{
- struct bio *new = bio_alloc(gfp, nr_pages);
+ struct bio *new = bio_new(bdev, sect, op, opf, gfp, nr_pages);

if (bio) {
bio_chain(bio, new);
submit_bio(bio);
}

- new->bi_iter.bi_sector = sect;
- bio_set_dev(new, bdev);
- bio_set_op_attrs(new, op, opf);
-
return new;
}

diff --git a/include/linux/bio.h b/include/linux/bio.h
index c74857cf1252..2a09ba100546 100644
--- a/include/linux/bio.h
+++ b/include/linux/bio.h
@@ -826,5 +826,30 @@ static inline void bio_set_polled(struct bio *bio, struct kiocb *kiocb)
if (!is_sync_kiocb(kiocb))
bio->bi_opf |= REQ_NOWAIT;
}
+/**
+ * bio_new - allcate and initialize new bio
+ * @bdev: blockdev to issue discard for
+ * @sector: start sector
+ * @op: REQ_OP_XXX from enum req_opf
+ * @op_flags: REQ_XXX from enum req_flag_bits
+ * @max_bvecs: maximum bvec to be allocated for this bio
+ * @gfp_mask: memory allocation flags (for bio_alloc)
+ *
+ * Description:
+ * Allocates, initializes common members, and returns a new bio.
+ */
+static inline struct bio *bio_new(struct block_device *bdev, sector_t sector,
+ unsigned int op, unsigned int op_flags,
+ unsigned int max_bvecs, gfp_t gfp_mask)
+{
+ unsigned nr_bvec = clamp_t(unsigned int, max_bvecs, 0, BIO_MAX_PAGES);
+ struct bio *bio = bio_alloc(gfp_mask, nr_bvec);
+
+ bio_set_dev(bio, bdev);
+ bio->bi_iter.bi_sector = sector;
+ bio_set_op_attrs(bio, op, op_flags);
+
+ return bio;
+}

#endif /* __LINUX_BIO_H */
--
2.22.1