From: Jason Wang <jasowang@redhat.com>
To: Stefan Hajnoczi <stefanha@redhat.com>,
virtualization@lists.linux-foundation.org
Cc: linux-block@vger.kernel.org, linux-kernel@vger.kernel.org,
Christoph Hellwig <hch@lst.de>,
Paolo Bonzini <pbonzini@redhat.com>, Jens Axboe <axboe@kernel.dk>,
slp@redhat.com, sgarzare@redhat.com,
"Michael S. Tsirkin" <mst@redhat.com>
Subject: Re: [PATCH 2/3] virtio_blk: avoid repeating vblk->vqs[qid]
Date: Tue, 25 May 2021 10:25:16 +0800 [thread overview]
Message-ID: <caf006e5-760f-23c9-64a6-35cd6e1f33f4@redhat.com> (raw)
In-Reply-To: <20210520141305.355961-3-stefanha@redhat.com>
在 2021/5/20 下午10:13, Stefan Hajnoczi 写道:
> 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 <stefanha@redhat.com>
Acked-by: Jason Wang <jasowang@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;
> }
>
next prev parent reply other threads:[~2021-05-25 2:25 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-05-20 14:13 [PATCH 0/3] virtio_blk: blk-mq io_poll support Stefan Hajnoczi
2021-05-20 14:13 ` [PATCH 1/3] virtio: add virtioqueue_more_used() Stefan Hajnoczi
2021-05-25 2:23 ` Jason Wang
2021-05-25 8:48 ` Stefan Hajnoczi
2021-05-20 14:13 ` [PATCH 2/3] virtio_blk: avoid repeating vblk->vqs[qid] Stefan Hajnoczi
2021-05-25 2:25 ` Jason Wang [this message]
2021-05-20 14:13 ` [PATCH 3/3] virtio_blk: implement blk_mq_ops->poll() Stefan Hajnoczi
2021-05-24 14:59 ` Christoph Hellwig
2021-05-25 7:22 ` Paolo Bonzini
2021-05-25 7:38 ` Ming Lei
2021-05-25 8:06 ` Paolo Bonzini
2021-05-25 13:20 ` Stefan Hajnoczi
2021-05-25 13:19 ` Stefan Hajnoczi
2021-05-25 3:21 ` Jason Wang
2021-05-25 8:59 ` Stefan Hajnoczi
2021-05-27 5:48 ` Jason Wang
2021-06-03 15:24 ` Stefan Hajnoczi
2021-05-27 2:44 ` Ming Lei
2021-06-03 15:12 ` Stefan Hajnoczi
2021-06-03 15:30 ` [PATCH 0/3] virtio_blk: blk-mq io_poll support Stefan Hajnoczi
2021-06-16 7:43 ` Christoph Hellwig
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