struct virtio_blk_vq is accessed in many places. Introduce "vbq" local
variables to avoid repeating vblk->vqs[qid] throughout the code. The
patches that follow will add more accesses, making the payoff even
greater.

virtio_commit_rqs() calls the local variable "vq", which is easily
confused with struct virtqueue. Rename to "vbq" for clarity.

Signed-off-by: Stefan Hajnoczi <stefa...@redhat.com>
---
 drivers/block/virtio_blk.c | 34 +++++++++++++++++-----------------
 1 file changed, 17 insertions(+), 17 deletions(-)

diff --git a/drivers/block/virtio_blk.c b/drivers/block/virtio_blk.c
index b9fa3ef5b57c..fc0fb1dcd399 100644
--- a/drivers/block/virtio_blk.c
+++ b/drivers/block/virtio_blk.c
@@ -174,16 +174,16 @@ static inline void virtblk_request_done(struct request 
*req)
 static void virtblk_done(struct virtqueue *vq)
 {
        struct virtio_blk *vblk = vq->vdev->priv;
+       struct virtio_blk_vq *vbq = &vblk->vqs[vq->index];
        bool req_done = false;
-       int qid = vq->index;
        struct virtblk_req *vbr;
        unsigned long flags;
        unsigned int len;
 
-       spin_lock_irqsave(&vblk->vqs[qid].lock, flags);
+       spin_lock_irqsave(&vbq->lock, flags);
        do {
                virtqueue_disable_cb(vq);
-               while ((vbr = virtqueue_get_buf(vblk->vqs[qid].vq, &len)) != 
NULL) {
+               while ((vbr = virtqueue_get_buf(vq, &len)) != NULL) {
                        struct request *req = blk_mq_rq_from_pdu(vbr);
 
                        if (likely(!blk_should_fake_timeout(req->q)))
@@ -197,32 +197,32 @@ static void virtblk_done(struct virtqueue *vq)
        /* In case queue is stopped waiting for more buffers. */
        if (req_done)
                blk_mq_start_stopped_hw_queues(vblk->disk->queue, true);
-       spin_unlock_irqrestore(&vblk->vqs[qid].lock, flags);
+       spin_unlock_irqrestore(&vbq->lock, flags);
 }
 
 static void virtio_commit_rqs(struct blk_mq_hw_ctx *hctx)
 {
        struct virtio_blk *vblk = hctx->queue->queuedata;
-       struct virtio_blk_vq *vq = &vblk->vqs[hctx->queue_num];
+       struct virtio_blk_vq *vbq = &vblk->vqs[hctx->queue_num];
        bool kick;
 
-       spin_lock_irq(&vq->lock);
-       kick = virtqueue_kick_prepare(vq->vq);
-       spin_unlock_irq(&vq->lock);
+       spin_lock_irq(&vbq->lock);
+       kick = virtqueue_kick_prepare(vbq->vq);
+       spin_unlock_irq(&vbq->lock);
 
        if (kick)
-               virtqueue_notify(vq->vq);
+               virtqueue_notify(vbq->vq);
 }
 
 static blk_status_t virtio_queue_rq(struct blk_mq_hw_ctx *hctx,
                           const struct blk_mq_queue_data *bd)
 {
        struct virtio_blk *vblk = hctx->queue->queuedata;
+       struct virtio_blk_vq *vbq = &vblk->vqs[hctx->queue_num];
        struct request *req = bd->rq;
        struct virtblk_req *vbr = blk_mq_rq_to_pdu(req);
        unsigned long flags;
        unsigned int num;
-       int qid = hctx->queue_num;
        int err;
        bool notify = false;
        bool unmap = false;
@@ -274,16 +274,16 @@ static blk_status_t virtio_queue_rq(struct blk_mq_hw_ctx 
*hctx,
                        vbr->out_hdr.type |= cpu_to_virtio32(vblk->vdev, 
VIRTIO_BLK_T_IN);
        }
 
-       spin_lock_irqsave(&vblk->vqs[qid].lock, flags);
-       err = virtblk_add_req(vblk->vqs[qid].vq, vbr, vbr->sg, num);
+       spin_lock_irqsave(&vbq->lock, flags);
+       err = virtblk_add_req(vbq->vq, vbr, vbr->sg, num);
        if (err) {
-               virtqueue_kick(vblk->vqs[qid].vq);
+               virtqueue_kick(vbq->vq);
                /* Don't stop the queue if -ENOMEM: we may have failed to
                 * bounce the buffer due to global resource outage.
                 */
                if (err == -ENOSPC)
                        blk_mq_stop_hw_queue(hctx);
-               spin_unlock_irqrestore(&vblk->vqs[qid].lock, flags);
+               spin_unlock_irqrestore(&vbq->lock, flags);
                switch (err) {
                case -ENOSPC:
                        return BLK_STS_DEV_RESOURCE;
@@ -294,12 +294,12 @@ static blk_status_t virtio_queue_rq(struct blk_mq_hw_ctx 
*hctx,
                }
        }
 
-       if (bd->last && virtqueue_kick_prepare(vblk->vqs[qid].vq))
+       if (bd->last && virtqueue_kick_prepare(vbq->vq))
                notify = true;
-       spin_unlock_irqrestore(&vblk->vqs[qid].lock, flags);
+       spin_unlock_irqrestore(&vbq->lock, flags);
 
        if (notify)
-               virtqueue_notify(vblk->vqs[qid].vq);
+               virtqueue_notify(vbq->vq);
        return BLK_STS_OK;
 }
 
-- 
2.31.1

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