[PATCH V5 6/6] nvmet: add bio get helper for different backends

[Chaitanya Kulkarni]

With the addition of the zns backend now we have three different
backends with inline bio optimization. That leads to having
duplicate code in for allocating or initializing the bio in all
three backends: generic bdev, passsthru, and generic zns.

Add a helper function to reduce the duplicate code such that helper
function accepts the bi_end_io callback which gets initialize for the
non-inline bio_alloc() case. This is due to the special case needed for
the passthru backend non-inline bio allocation bio_alloc() where we set
the bio->bi_end_io = bio_put. For rest of the backends, we set the same
bi_end_io callback for inline and non-inline cases, that is for generic
bdev we set to nvmet_bio_done() and for generic zns we set to NULL.

Signed-off-by: Chaitanya Kulkarni <chaitanya.kulkarni at wdc.com>
---
 drivers/nvme/target/io-cmd-bdev.c |  7 +------
 drivers/nvme/target/nvmet.h       | 16 ++++++++++++++++
 drivers/nvme/target/passthru.c    |  8 +-------
 drivers/nvme/target/zns.c         |  8 +-------
 4 files changed, 19 insertions(+), 20 deletions(-)

diff --git a/drivers/nvme/target/io-cmd-bdev.c b/drivers/nvme/target/io-cmd-bdev.c
index 0ce6d165dc4f..6ffd84a620e7 100644
--- a/drivers/nvme/target/io-cmd-bdev.c
+++ b/drivers/nvme/target/io-cmd-bdev.c
@@ -265,12 +265,7 @@ static void nvmet_bdev_execute_rw(struct nvmet_req *req)
 
 	sector = nvmet_lba_to_sect(req->ns, req->cmd->rw.slba);
 
-	if (req->transfer_len <= NVMET_MAX_INLINE_DATA_LEN) {
-		bio = &req->b.inline_bio;
-		bio_init(bio, req->inline_bvec, ARRAY_SIZE(req->inline_bvec));
-	} else {
-		bio = bio_alloc(GFP_KERNEL, min(sg_cnt, BIO_MAX_PAGES));
-	}
+	bio = nvmet_req_bio_get(req, NULL);
 	bio_set_dev(bio, req->ns->bdev);
 	bio->bi_iter.bi_sector = sector;
 	bio->bi_private = req;
diff --git a/drivers/nvme/target/nvmet.h b/drivers/nvme/target/nvmet.h
index 7ef416de4f6f..5d187642a3fa 100644
--- a/drivers/nvme/target/nvmet.h
+++ b/drivers/nvme/target/nvmet.h
@@ -618,6 +618,22 @@ static inline sector_t nvmet_lba_to_sect(struct nvmet_ns *ns, __le64 lba)
 	return le64_to_cpu(lba) << (ns->blksize_shift - SECTOR_SHIFT);
 }
 
+static inline struct bio *nvmet_req_bio_get(struct nvmet_req *req,
+					    bio_end_io_t *bi_end_io)
+{
+	struct bio *bio;
+
+	if (req->transfer_len <= NVMET_MAX_INLINE_DATA_LEN) {
+		bio = &req->b.inline_bio;
+		bio_init(bio, req->inline_bvec, ARRAY_SIZE(req->inline_bvec));
+		return bio;
+	}
+
+	bio = bio_alloc(GFP_KERNEL, req->sg_cnt);
+	bio->bi_end_io = bi_end_io;
+	return bio;
+}
+
 static inline void nvmet_req_bio_put(struct nvmet_req *req, struct bio *bio)
 {
 	if (bio != &req->b.inline_bio)
diff --git a/drivers/nvme/target/passthru.c b/drivers/nvme/target/passthru.c
index c2858ea8cabc..a4a73d64c603 100644
--- a/drivers/nvme/target/passthru.c
+++ b/drivers/nvme/target/passthru.c
@@ -194,13 +194,7 @@ static int nvmet_passthru_map_sg(struct nvmet_req *req, struct request *rq)
 	if (req->sg_cnt > BIO_MAX_PAGES)
 		return -EINVAL;
 
-	if (req->transfer_len <= NVMET_MAX_INLINE_DATA_LEN) {
-		bio = &req->p.inline_bio;
-		bio_init(bio, req->inline_bvec, ARRAY_SIZE(req->inline_bvec));
-	} else {
-		bio = bio_alloc(GFP_KERNEL, min(req->sg_cnt, BIO_MAX_PAGES));
-		bio->bi_end_io = bio_put;
-	}
+	bio = nvmet_req_bio_get(req, bio_put);
 	bio->bi_opf = req_op(rq);
 
 	for_each_sg(req->sg, sg, req->sg_cnt, i) {
diff --git a/drivers/nvme/target/zns.c b/drivers/nvme/target/zns.c
index d2d1538f92d4..dc841f8ae7b3 100644
--- a/drivers/nvme/target/zns.c
+++ b/drivers/nvme/target/zns.c
@@ -279,13 +279,7 @@ void nvmet_bdev_execute_zone_append(struct nvmet_req *req)
 		return;
 	}
 
-	if (req->transfer_len <= NVMET_MAX_INLINE_DATA_LEN) {
-		bio = &req->b.inline_bio;
-		bio_init(bio, req->inline_bvec, ARRAY_SIZE(req->inline_bvec));
-	} else {
-		bio = bio_alloc(GFP_KERNEL, req->sg_cnt);
-	}
-
+	bio = nvmet_req_bio_get(req, NULL);
 	bio_set_dev(bio, req->ns->bdev);
 	bio->bi_iter.bi_sector = sect;
 	bio->bi_opf = REQ_OP_ZONE_APPEND | REQ_SYNC | REQ_IDLE;
-- 
2.22.1