[PATCH for-next v11 06/13] block: factor out blk_rq_map_bio_alloc helper

[Anuj Gupta <anuj20.g@xxxxxxxxxxx>]

From: Kanchan Joshi <joshi.k@xxxxxxxxxxx>

Move bio allocation logic from bio_map_user_iov to a new helper
blk_rq_map_bio_alloc. It is named so because functionality is opposite
of what is done inside blk_mq_map_bio_put. This is a prep patch.

Signed-off-by: Kanchan Joshi <joshi.k@xxxxxxxxxxx>
---
 block/blk-map.c | 33 ++++++++++++++++++++++-----------
 1 file changed, 22 insertions(+), 11 deletions(-)

diff --git a/block/blk-map.c b/block/blk-map.c
index d913ef92a9fe..9e37a03b8a21 100644
--- a/block/blk-map.c
+++ b/block/blk-map.c
@@ -241,17 +241,10 @@ static void blk_mq_map_bio_put(struct bio *bio)
 	}
 }
 
-static int bio_map_user_iov(struct request *rq, struct iov_iter *iter,
-		gfp_t gfp_mask)
+static struct bio *blk_rq_map_bio_alloc(struct request *rq,
+		unsigned int nr_vecs, gfp_t gfp_mask)
 {
-	unsigned int max_sectors = queue_max_hw_sectors(rq->q);
-	unsigned int nr_vecs = iov_iter_npages(iter, BIO_MAX_VECS);
 	struct bio *bio;
-	int ret;
-	int j;
-
-	if (!iov_iter_count(iter))
-		return -EINVAL;
 
 	if (rq->cmd_flags & REQ_POLLED) {
 		blk_opf_t opf = rq->cmd_flags | REQ_ALLOC_CACHE;
@@ -259,13 +252,31 @@ static int bio_map_user_iov(struct request *rq, struct iov_iter *iter,
 		bio = bio_alloc_bioset(NULL, nr_vecs, opf, gfp_mask,
 					&fs_bio_set);
 		if (!bio)
-			return -ENOMEM;
+			return NULL;
 	} else {
 		bio = bio_kmalloc(nr_vecs, gfp_mask);
 		if (!bio)
-			return -ENOMEM;
+			return NULL;
 		bio_init(bio, NULL, bio->bi_inline_vecs, nr_vecs, req_op(rq));
 	}
+	return bio;
+}
+
+static int bio_map_user_iov(struct request *rq, struct iov_iter *iter,
+		gfp_t gfp_mask)
+{
+	unsigned int max_sectors = queue_max_hw_sectors(rq->q);
+	unsigned int nr_vecs = iov_iter_npages(iter, BIO_MAX_VECS);
+	struct bio *bio;
+	int ret;
+	int j;
+
+	if (!iov_iter_count(iter))
+		return -EINVAL;
+
+	bio = blk_rq_map_bio_alloc(rq, nr_vecs, gfp_mask);
+	if (bio == NULL)
+		return -ENOMEM;
 
 	while (iov_iter_count(iter)) {
 		struct page **pages, *stack_pages[UIO_FASTIOV];
-- 
2.25.1