[RFC PATCH 01/37] block: introduce bio_init_fields() helper

[Chaitanya Kulkarni]

There are several places in the file-system, block layer, device drivers
where struct bio members such as bdev, sector, private, end io callback,
io priority, write hints are initialized where we can use a helper
function.

This pach introduces a helper function which we use in the block lyaer
code. Subsequent patches use this function to reduce repeated code.

Signed-off-by: Chaitanya Kulkarni <chaitanya.kulkarni@xxxxxxx>
---
 block/blk-lib.c     | 13 +++++--------
 include/linux/bio.h | 13 +++++++++++++
 2 files changed, 18 insertions(+), 8 deletions(-)

diff --git a/block/blk-lib.c b/block/blk-lib.c
index 752f9c722062..5ee488c1bcc6 100644
--- a/block/blk-lib.c
+++ b/block/blk-lib.c
@@ -95,8 +95,7 @@ int __blkdev_issue_discard(struct block_device *bdev, sector_t sector,
 		WARN_ON_ONCE((req_sects << 9) > UINT_MAX);
 
 		bio = blk_next_bio(bio, 0, gfp_mask);
-		bio->bi_iter.bi_sector = sector;
-		bio_set_dev(bio, bdev);
+		bio_init_fields(bio, bdev, sector, NULL, NULL, 0, 0);
 		bio_set_op_attrs(bio, op, 0);
 
 		bio->bi_iter.bi_size = req_sects << 9;
@@ -189,8 +188,7 @@ static int __blkdev_issue_write_same(struct block_device *bdev, sector_t sector,
 
 	while (nr_sects) {
 		bio = blk_next_bio(bio, 1, gfp_mask);
-		bio->bi_iter.bi_sector = sector;
-		bio_set_dev(bio, bdev);
+		bio_init_fields(bio, bdev, sector, NULL, NULL, 0, 0);
 		bio->bi_vcnt = 1;
 		bio->bi_io_vec->bv_page = page;
 		bio->bi_io_vec->bv_offset = 0;
@@ -265,8 +263,7 @@ static int __blkdev_issue_write_zeroes(struct block_device *bdev,
 
 	while (nr_sects) {
 		bio = blk_next_bio(bio, 0, gfp_mask);
-		bio->bi_iter.bi_sector = sector;
-		bio_set_dev(bio, bdev);
+		bio_init_fields(bio, bdev, sector, NULL, NULL, 0, 0);
 		bio->bi_opf = REQ_OP_WRITE_ZEROES;
 		if (flags & BLKDEV_ZERO_NOUNMAP)
 			bio->bi_opf |= REQ_NOUNMAP;
@@ -317,8 +314,8 @@ static int __blkdev_issue_zero_pages(struct block_device *bdev,
 	while (nr_sects != 0) {
 		bio = blk_next_bio(bio, __blkdev_sectors_to_bio_pages(nr_sects),
 				   gfp_mask);
-		bio->bi_iter.bi_sector = sector;
-		bio_set_dev(bio, bdev);
+		bio_init_fields(bio, bdev, sector, NULL, NULL, 0, 0);
+
 		bio_set_op_attrs(bio, REQ_OP_WRITE, 0);
 
 		while (nr_sects != 0) {
diff --git a/include/linux/bio.h b/include/linux/bio.h
index 1edda614f7ce..fbeaa5e42a5d 100644
--- a/include/linux/bio.h
+++ b/include/linux/bio.h
@@ -820,4 +820,17 @@ static inline void bio_set_polled(struct bio *bio, struct kiocb *kiocb)
 		bio->bi_opf |= REQ_NOWAIT;
 }
 
+static inline void bio_init_fields(struct bio *bio, struct block_device *bdev,
+				   sector_t sect, void *priv,
+				   bio_end_io_t *end_io,
+				   unsigned short prio, unsigned short whint)
+{
+	bio_set_dev(bio, bdev);
+	bio->bi_iter.bi_sector = sect;
+	bio->bi_private = priv;
+	bio->bi_end_io = end_io;
+	bio->bi_ioprio = prio;
+	bio->bi_write_hint = whint;
+}
+
 #endif /* __LINUX_BIO_H */
-- 
2.22.1