On 02/12/2013 08:23 PM, Paolo Bonzini wrote:
> Right now, both virtblk_add_req and virtblk_add_req_wait call
> virtqueue_add_buf. To prepare for the next patches, abstract the call
> to virtqueue_add_buf into a new function __virtblk_add_req, and include
> the waiting logic directly in virtblk_add_req.
>
> Signed-off-by: Paolo Bonzini <pbonz...@redhat.com>
Reviewed-by: Asias He <as...@redhat.com>
> ---
> drivers/block/virtio_blk.c | 55
> ++++++++++++++++----------------------------
> 1 files changed, 20 insertions(+), 35 deletions(-)
>
> diff --git a/drivers/block/virtio_blk.c b/drivers/block/virtio_blk.c
> index 8ad21a2..fd8a689 100644
> --- a/drivers/block/virtio_blk.c
> +++ b/drivers/block/virtio_blk.c
> @@ -100,50 +100,39 @@ static inline struct virtblk_req
> *virtblk_alloc_req(struct virtio_blk *vblk,
> return vbr;
> }
>
> -static void virtblk_add_buf_wait(struct virtio_blk *vblk,
> - struct virtblk_req *vbr,
> - unsigned long out,
> - unsigned long in)
> +static inline int __virtblk_add_req(struct virtqueue *vq,
> + struct virtblk_req *vbr,
> + unsigned long out,
> + unsigned long in)
> {
> + return virtqueue_add_buf(vq, vbr->sg, out, in, vbr, GFP_ATOMIC);
> +}
> +
> +static void virtblk_add_req(struct virtblk_req *vbr,
> + unsigned int out, unsigned int in)
> +{
> + struct virtio_blk *vblk = vbr->vblk;
> DEFINE_WAIT(wait);
> + int ret;
>
> - for (;;) {
> + spin_lock_irq(vblk->disk->queue->queue_lock);
> + while (unlikely((ret = __virtblk_add_req(vblk->vq, vbr,
> + out, in)) < 0)) {
> prepare_to_wait_exclusive(&vblk->queue_wait, &wait,
> TASK_UNINTERRUPTIBLE);
>
> + spin_unlock_irq(vblk->disk->queue->queue_lock);
> + io_schedule();
> spin_lock_irq(vblk->disk->queue->queue_lock);
> - if (virtqueue_add_buf(vblk->vq, vbr->sg, out, in, vbr,
> - GFP_ATOMIC) < 0) {
> - spin_unlock_irq(vblk->disk->queue->queue_lock);
> - io_schedule();
> - } else {
> - virtqueue_kick(vblk->vq);
> - spin_unlock_irq(vblk->disk->queue->queue_lock);
> - break;
> - }
>
> + finish_wait(&vblk->queue_wait, &wait);
> }
>
> - finish_wait(&vblk->queue_wait, &wait);
> -}
> -
> -static inline void virtblk_add_req(struct virtblk_req *vbr,
> - unsigned int out, unsigned int in)
> -{
> - struct virtio_blk *vblk = vbr->vblk;
> -
> - spin_lock_irq(vblk->disk->queue->queue_lock);
> - if (unlikely(virtqueue_add_buf(vblk->vq, vbr->sg, out, in, vbr,
> - GFP_ATOMIC) < 0)) {
> - spin_unlock_irq(vblk->disk->queue->queue_lock);
> - virtblk_add_buf_wait(vblk, vbr, out, in);
> - return;
> - }
> virtqueue_kick(vblk->vq);
> spin_unlock_irq(vblk->disk->queue->queue_lock);
> }
>
> -static int virtblk_bio_send_flush(struct virtblk_req *vbr)
> +static void virtblk_bio_send_flush(struct virtblk_req *vbr)
> {
> unsigned int out = 0, in = 0;
>
> @@ -155,11 +144,9 @@ static int virtblk_bio_send_flush(struct virtblk_req
> *vbr)
> sg_set_buf(&vbr->sg[out + in++], &vbr->status, sizeof(vbr->status));
>
> virtblk_add_req(vbr, out, in);
> -
> - return 0;
> }
>
> -static int virtblk_bio_send_data(struct virtblk_req *vbr)
> +static void virtblk_bio_send_data(struct virtblk_req *vbr)
> {
> struct virtio_blk *vblk = vbr->vblk;
> unsigned int num, out = 0, in = 0;
> @@ -188,8 +175,6 @@ static int virtblk_bio_send_data(struct virtblk_req *vbr)
> }
>
> virtblk_add_req(vbr, out, in);
> -
> - return 0;
> }
>
> static void virtblk_bio_send_data_work(struct work_struct *work)
>
--
Asias
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