[RFC PATCH 01/34] block: move common code into blk_next_bio()

[Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>]

blk_next_bio() is the central function which allocates the bios for
discard, write-same, write-zeroes and zone-mgmt. The initialization of
various bio members is duplicated in disacrd, write-same, write-zeores.
In this preparation patch we add bdev, sector, op, and opf arguments to
the blk_next_bio() to reduce the duplication. 

In the next patch we introduce bio_new(), this prepration patch allows
us to call it inside blk_next_bio().

Signed-off-by: Chaitanya Kulkarni <chaitanya.kulkarni@wdc.com>
---
 block/blk-lib.c   | 36 +++++++++++++++---------------------
 block/blk-zoned.c |  4 +---
 block/blk.h       |  5 +++--
 3 files changed, 19 insertions(+), 26 deletions(-)

diff --git a/block/blk-lib.c b/block/blk-lib.c
index 752f9c722062..fb486a0bdb58 100644
--- a/block/blk-lib.c
+++ b/block/blk-lib.c
@@ -10,7 +10,9 @@
 
 #include "blk.h"
 
-struct bio *blk_next_bio(struct bio *bio, unsigned int nr_pages, gfp_t gfp)
+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);
 
@@ -19,6 +21,10 @@ struct bio *blk_next_bio(struct bio *bio, unsigned int nr_pages, gfp_t gfp)
 		submit_bio(bio);
 	}
 
+	new->bi_iter.bi_sector = sect;
+	bio_set_dev(new, bdev);
+	bio_set_op_attrs(new, op, opf);
+
 	return new;
 }
 
@@ -94,11 +100,7 @@ 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_set_op_attrs(bio, op, 0);
-
+		bio = blk_next_bio(bio, bdev, sector, op, 0, 0, gfp_mask);
 		bio->bi_iter.bi_size = req_sects << 9;
 		sector += req_sects;
 		nr_sects -= req_sects;
@@ -168,6 +170,7 @@ static int __blkdev_issue_write_same(struct block_device *bdev, sector_t sector,
 {
 	struct request_queue *q = bdev_get_queue(bdev);
 	unsigned int max_write_same_sectors;
+	unsigned int op = REQ_OP_WRITE_SAME;
 	struct bio *bio = *biop;
 	sector_t bs_mask;
 
@@ -188,14 +191,11 @@ static int __blkdev_issue_write_same(struct block_device *bdev, sector_t sector,
 	max_write_same_sectors = bio_allowed_max_sectors(q);
 
 	while (nr_sects) {
-		bio = blk_next_bio(bio, 1, gfp_mask);
-		bio->bi_iter.bi_sector = sector;
-		bio_set_dev(bio, bdev);
+		bio = blk_next_bio(bio, bdev, sector, op, 0, 1, gfp_mask);
 		bio->bi_vcnt = 1;
 		bio->bi_io_vec->bv_page = page;
 		bio->bi_io_vec->bv_offset = 0;
 		bio->bi_io_vec->bv_len = bdev_logical_block_size(bdev);
-		bio_set_op_attrs(bio, REQ_OP_WRITE_SAME, 0);
 
 		if (nr_sects > max_write_same_sectors) {
 			bio->bi_iter.bi_size = max_write_same_sectors << 9;
@@ -249,7 +249,9 @@ static int __blkdev_issue_write_zeroes(struct block_device *bdev,
 {
 	struct bio *bio = *biop;
 	unsigned int max_write_zeroes_sectors;
+	unsigned int op = REQ_OP_WRITE_ZEROES;
 	struct request_queue *q = bdev_get_queue(bdev);
+	unsigned int opf = flags & BLKDEV_ZERO_NOUNMAP ? REQ_NOUNMAP : 0;
 
 	if (!q)
 		return -ENXIO;
@@ -264,13 +266,7 @@ static int __blkdev_issue_write_zeroes(struct block_device *bdev,
 		return -EOPNOTSUPP;
 
 	while (nr_sects) {
-		bio = blk_next_bio(bio, 0, gfp_mask);
-		bio->bi_iter.bi_sector = sector;
-		bio_set_dev(bio, bdev);
-		bio->bi_opf = REQ_OP_WRITE_ZEROES;
-		if (flags & BLKDEV_ZERO_NOUNMAP)
-			bio->bi_opf |= REQ_NOUNMAP;
-
+		bio = blk_next_bio(bio, bdev, sector, op, opf, 0, gfp_mask);
 		if (nr_sects > max_write_zeroes_sectors) {
 			bio->bi_iter.bi_size = max_write_zeroes_sectors << 9;
 			nr_sects -= max_write_zeroes_sectors;
@@ -303,6 +299,7 @@ static int __blkdev_issue_zero_pages(struct block_device *bdev,
 		sector_t sector, sector_t nr_sects, gfp_t gfp_mask,
 		struct bio **biop)
 {
+	unsigned int nr_pages = __blkdev_sectors_to_bio_pages(nr_sects);
 	struct request_queue *q = bdev_get_queue(bdev);
 	struct bio *bio = *biop;
 	int bi_size = 0;
@@ -315,11 +312,8 @@ static int __blkdev_issue_zero_pages(struct block_device *bdev,
 		return -EPERM;
 
 	while (nr_sects != 0) {
-		bio = blk_next_bio(bio, __blkdev_sectors_to_bio_pages(nr_sects),
+		bio = blk_next_bio(bio, bdev, sector, REQ_OP_WRITE, 0, nr_pages,
 				   gfp_mask);
-		bio->bi_iter.bi_sector = sector;
-		bio_set_dev(bio, bdev);
-		bio_set_op_attrs(bio, REQ_OP_WRITE, 0);
 
 		while (nr_sects != 0) {
 			sz = min((sector_t) PAGE_SIZE, nr_sects << 9);
diff --git a/block/blk-zoned.c b/block/blk-zoned.c
index 7a68b6e4300c..68e77628348d 100644
--- a/block/blk-zoned.c
+++ b/block/blk-zoned.c
@@ -231,8 +231,7 @@ int blkdev_zone_mgmt(struct block_device *bdev, enum req_opf op,
 		return -EINVAL;
 
 	while (sector < end_sector) {
-		bio = blk_next_bio(bio, 0, gfp_mask);
-		bio_set_dev(bio, bdev);
+		bio = blk_next_bio(bio, bdev, 0 , op, REQ_SYNC, 0, gfp_mask);
 
 		/*
 		 * Special case for the zone reset operation that reset all
@@ -244,7 +243,6 @@ int blkdev_zone_mgmt(struct block_device *bdev, enum req_opf op,
 			break;
 		}
 
-		bio->bi_opf = op | REQ_SYNC;
 		bio->bi_iter.bi_sector = sector;
 		sector += zone_sectors;
 
diff --git a/block/blk.h b/block/blk.h
index 0198335c5838..0a278bae5478 100644
--- a/block/blk.h
+++ b/block/blk.h
@@ -329,8 +329,9 @@ extern int blk_iolatency_init(struct request_queue *q);
 static inline int blk_iolatency_init(struct request_queue *q) { return 0; }
 #endif
 
-struct bio *blk_next_bio(struct bio *bio, unsigned int nr_pages, gfp_t gfp);
-
+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);
 #ifdef CONFIG_BLK_DEV_ZONED
 void blk_queue_free_zone_bitmaps(struct request_queue *q);
 #else
-- 
2.22.1