[PATCH V2 1/4] block: create payloadless issue bio helper

[Chaitanya Kulkarni <chaitanya.kulkarni@xxxxxxx>]

This is a prep-patch that creates a helper to submit payloadless bio
with all the required arguments. This is needed to avoid the code
repetition in blk-lib,c so that new payloadless ops can use it.  

Signed-off-by: Chaitanya Kulkarni <chaitanya.kulkarni@xxxxxxx>
---
 block/blk-lib.c | 51 +++++++++++++++++++++++++++++--------------------
 1 file changed, 30 insertions(+), 21 deletions(-)

diff --git a/block/blk-lib.c b/block/blk-lib.c
index 5f2c429d4378..8e53e393703c 100644
--- a/block/blk-lib.c
+++ b/block/blk-lib.c
@@ -209,13 +209,40 @@ int blkdev_issue_write_same(struct block_device *bdev, sector_t sector,
 }
 EXPORT_SYMBOL(blkdev_issue_write_same);
 
+static void __blkdev_issue_payloadless(struct block_device *bdev,
+		unsigned op, sector_t sector, sector_t nr_sects, gfp_t gfp_mask,
+		struct bio **biop, unsigned bio_opf, unsigned int max_sectors)
+{
+	struct bio *bio = *biop;
+
+	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 = op;
+		bio->bi_opf |= bio_opf;
+
+		if (nr_sects > max_sectors) {
+			bio->bi_iter.bi_size = max_sectors << 9;
+			nr_sects -= max_sectors;
+			sector += max_sectors;
+		} else {
+			bio->bi_iter.bi_size = nr_sects << 9;
+			nr_sects = 0;
+		}
+		cond_resched();
+	}
+
+	*biop = bio;
+}
+
 static int __blkdev_issue_write_zeroes(struct block_device *bdev,
 		sector_t sector, sector_t nr_sects, gfp_t gfp_mask,
 		struct bio **biop, unsigned flags)
 {
-	struct bio *bio = *biop;
 	unsigned int max_write_zeroes_sectors;
 	struct request_queue *q = bdev_get_queue(bdev);
+	unsigned int unmap = (flags & BLKDEV_ZERO_NOUNMAP) ? REQ_NOUNMAP : 0;
 
 	if (!q)
 		return -ENXIO;
@@ -229,26 +256,8 @@ static int __blkdev_issue_write_zeroes(struct block_device *bdev,
 	if (max_write_zeroes_sectors == 0)
 		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;
-
-		if (nr_sects > max_write_zeroes_sectors) {
-			bio->bi_iter.bi_size = max_write_zeroes_sectors << 9;
-			nr_sects -= max_write_zeroes_sectors;
-			sector += max_write_zeroes_sectors;
-		} else {
-			bio->bi_iter.bi_size = nr_sects << 9;
-			nr_sects = 0;
-		}
-		cond_resched();
-	}
-
-	*biop = bio;
+	__blkdev_issue_payloadless(bdev, REQ_OP_WRITE_ZEROES, sector, nr_sects,
+		       gfp_mask, biop, unmap, max_write_zeroes_sectors);
 	return 0;
 }
 
-- 
2.22.0