virtio_blk: remove struct request backpointer from virtblk_req

We can simply use blk_mq_rq_from_pdu to get back at the request at
I/O completion time.

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

diff --git a/drivers/block/virtio_blk.c b/drivers/block/virtio_blk.c
index 3027d2e..7c730e2 100644 (file)
--- a/drivers/block/virtio_blk.c
+++ b/drivers/block/virtio_blk.c
@@ -53,7 +53,6 @@ struct virtio_blk {
 
 struct virtblk_req {
        struct scsi_request sreq;       /* for SCSI passthrough */
-       struct request *req;
        struct virtio_blk_outhdr out_hdr;
        struct virtio_scsi_inhdr in_hdr;
        u8 status;
@@ -148,7 +147,9 @@ static void virtblk_done(struct virtqueue *vq)
        do {
                virtqueue_disable_cb(vq);
                while ((vbr = virtqueue_get_buf(vblk->vqs[qid].vq, &len)) != NULL) {
-                       blk_mq_complete_request(vbr->req, vbr->req->errors);
+                       struct request *req = blk_mq_rq_from_pdu(vbr);
+
+                       blk_mq_complete_request(req, req->errors);
                        req_done = true;
                }
                if (unlikely(virtqueue_is_broken(vq)))
@@ -175,27 +176,26 @@ static int virtio_queue_rq(struct blk_mq_hw_ctx *hctx,
 
        BUG_ON(req->nr_phys_segments + 2 > vblk->sg_elems);
 
-       vbr->req = req;
        if (req_op(req) == REQ_OP_FLUSH) {
                vbr->out_hdr.type = cpu_to_virtio32(vblk->vdev, VIRTIO_BLK_T_FLUSH);
                vbr->out_hdr.sector = 0;
-               vbr->out_hdr.ioprio = cpu_to_virtio32(vblk->vdev, req_get_ioprio(vbr->req));
+               vbr->out_hdr.ioprio = cpu_to_virtio32(vblk->vdev, req_get_ioprio(req));
        } else {
                switch (req->cmd_type) {
                case REQ_TYPE_FS:
                        vbr->out_hdr.type = 0;
-                       vbr->out_hdr.sector = cpu_to_virtio64(vblk->vdev, blk_rq_pos(vbr->req));
-                       vbr->out_hdr.ioprio = cpu_to_virtio32(vblk->vdev, req_get_ioprio(vbr->req));
+                       vbr->out_hdr.sector = cpu_to_virtio64(vblk->vdev, blk_rq_pos(req));
+                       vbr->out_hdr.ioprio = cpu_to_virtio32(vblk->vdev, req_get_ioprio(req));
                        break;
                case REQ_TYPE_BLOCK_PC:
                        vbr->out_hdr.type = cpu_to_virtio32(vblk->vdev, VIRTIO_BLK_T_SCSI_CMD);
                        vbr->out_hdr.sector = 0;
-                       vbr->out_hdr.ioprio = cpu_to_virtio32(vblk->vdev, req_get_ioprio(vbr->req));
+                       vbr->out_hdr.ioprio = cpu_to_virtio32(vblk->vdev, req_get_ioprio(req));
                        break;
                case REQ_TYPE_DRV_PRIV:
                        vbr->out_hdr.type = cpu_to_virtio32(vblk->vdev, VIRTIO_BLK_T_GET_ID);
                        vbr->out_hdr.sector = 0;
-                       vbr->out_hdr.ioprio = cpu_to_virtio32(vblk->vdev, req_get_ioprio(vbr->req));
+                       vbr->out_hdr.ioprio = cpu_to_virtio32(vblk->vdev, req_get_ioprio(req));
                        break;
                default:
                        /* We don't put anything else in the queue. */
@@ -205,9 +205,9 @@ static int virtio_queue_rq(struct blk_mq_hw_ctx *hctx,
 
        blk_mq_start_request(req);
 
-       num = blk_rq_map_sg(hctx->queue, vbr->req, vbr->sg);
+       num = blk_rq_map_sg(hctx->queue, req, vbr->sg);
        if (num) {
-               if (rq_data_dir(vbr->req) == WRITE)
+               if (rq_data_dir(req) == WRITE)
                        vbr->out_hdr.type |= cpu_to_virtio32(vblk->vdev, VIRTIO_BLK_T_OUT);
                else
                        vbr->out_hdr.type |= cpu_to_virtio32(vblk->vdev, VIRTIO_BLK_T_IN);