block: factor out blk_rq_map_bio_alloc helper

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@samsung.com>
Link: https://lore.kernel.org/r/20220930062749.152261-10-anuj20.g@samsung.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

diff --git a/block/blk-map.c b/block/blk-map.c
index 84b13a4..d6ea377 100644 (file)
--- 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];