blk-mq: do not initialize req->special

Drivers can reach their private data easily using the blk_mq_rq_to_pdu
helper and don't need req->special.  By not initializing it code can
be simplified nicely, and we also shave off a few more instructions from
the I/O path.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Jens Axboe <axboe@fb.com>

2 files changed, 5 insertions, 5 deletions

diff --git a/drivers/block/null_blk.c b/drivers/block/null_blk.c
index 091b9ea14feb..71df69d90900 100644
--- a/drivers/block/null_blk.c
+++ b/drivers/block/null_blk.c
@@ -226,7 +226,7 @@ static void null_cmd_end_timer(struct nullb_cmd *cmd)
 
 static void null_softirq_done_fn(struct request *rq)
 {
-        end_cmd(rq->special);
+        end_cmd(blk_mq_rq_to_pdu(rq));
 }
 
 static inline void null_handle_cmd(struct nullb_cmd *cmd)
@@ -311,7 +311,7 @@ static void null_request_fn(struct request_queue *q)
 
 static int null_queue_rq(struct blk_mq_hw_ctx *hctx, struct request *rq)
 {
-        struct nullb_cmd *cmd = rq->special;
+        struct nullb_cmd *cmd = blk_mq_rq_to_pdu(rq);
 
         cmd->rq = rq;
         cmd->nq = hctx->driver_data;
diff --git a/drivers/block/virtio_blk.c b/drivers/block/virtio_blk.c
index 6d8a87f252de..c7d02bc9d945 100644
--- a/drivers/block/virtio_blk.c
+++ b/drivers/block/virtio_blk.c
@@ -112,7 +112,7 @@ static int __virtblk_add_req(struct virtqueue *vq,
 
 static inline void virtblk_request_done(struct request *req)
 {
-        struct virtblk_req *vbr = req->special;
+        struct virtblk_req *vbr = blk_mq_rq_to_pdu(req);
         int error = virtblk_result(vbr);
 
         if (req->cmd_type == REQ_TYPE_BLOCK_PC) {
@@ -154,7 +154,7 @@ static void virtblk_done(struct virtqueue *vq)
 static int virtio_queue_rq(struct blk_mq_hw_ctx *hctx, struct request *req)
 {
         struct virtio_blk *vblk = hctx->queue->queuedata;
-        struct virtblk_req *vbr = req->special;
+        struct virtblk_req *vbr = blk_mq_rq_to_pdu(req);
         unsigned long flags;
         unsigned int num;
         const bool last = (req->cmd_flags & REQ_END) != 0;
@@ -501,7 +501,7 @@ static int virtblk_init_vbr(void *data, struct blk_mq_hw_ctx *hctx,
                              struct request *rq, unsigned int nr)
 {
         struct virtio_blk *vblk = data;
-        struct virtblk_req *vbr = rq->special;
+        struct virtblk_req *vbr = blk_mq_rq_to_pdu(rq);
 
         sg_init_table(vbr->sg, vblk->sg_elems);
         return 0;