virtio_ring: remove unnecessary to_vvq() call

[PATCH] virtio_ring: remove unnecessary to_vvq() call

Posted by Bo Liu 3 years, 6 months ago

It passes '_vq' to vring_free(), which still calls to_vvq()
to get 'vq', let's directly pass 'vq'. It can avoid
unnecessary call of to_vvq() in hot path.

Signed-off-by: Bo Liu <liubo03@inspur.com>
---
 drivers/virtio/virtio_ring.c | 12 +++++-------
 1 file changed, 5 insertions(+), 7 deletions(-)

diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c
index 8974c34b40fd..d6d77bf58802 100644
--- a/drivers/virtio/virtio_ring.c
+++ b/drivers/virtio/virtio_ring.c
@@ -221,7 +221,7 @@ static struct virtqueue *__vring_new_virtqueue(unsigned int index,
 					       void (*callback)(struct virtqueue *),
 					       const char *name);
 static struct vring_desc_extra *vring_alloc_desc_extra(unsigned int num);
-static void vring_free(struct virtqueue *_vq);
+static void vring_free(struct vring_virtqueue *vq);
 
 /*
  * Helpers.
@@ -1140,7 +1140,7 @@ static int virtqueue_resize_split(struct virtqueue *_vq, u32 num)
 	if (err)
 		goto err_state_extra;
 
-	vring_free(&vq->vq);
+	vring_free(vq);
 
 	virtqueue_vring_init_split(&vring_split, vq);
 
@@ -2059,7 +2059,7 @@ static int virtqueue_resize_packed(struct virtqueue *_vq, u32 num)
 	if (err)
 		goto err_state_extra;
 
-	vring_free(&vq->vq);
+	vring_free(vq);
 
 	virtqueue_vring_init_packed(&vring_packed, !!vq->vq.callback);
 
@@ -2649,10 +2649,8 @@ struct virtqueue *vring_new_virtqueue(unsigned int index,
 }
 EXPORT_SYMBOL_GPL(vring_new_virtqueue);
 
-static void vring_free(struct virtqueue *_vq)
+static void vring_free(struct vring_virtqueue *vq)
 {
-	struct vring_virtqueue *vq = to_vvq(_vq);
-
 	if (vq->we_own_ring) {
 		if (vq->packed_ring) {
 			vring_free_queue(vq->vq.vdev,
@@ -2693,7 +2691,7 @@ void vring_del_virtqueue(struct virtqueue *_vq)
 	list_del(&_vq->list);
 	spin_unlock(&vq->vq.vdev->vqs_list_lock);
 
-	vring_free(_vq);
+	vring_free(vq);
 
 	kfree(vq);
 }
-- 
2.27.0

Re: [PATCH] virtio_ring: remove unnecessary to_vvq() call

Posted by Michael S. Tsirkin 3 years, 6 months ago

On Mon, Sep 26, 2022 at 05:11:30AM -0400, Bo Liu wrote:
> It passes '_vq' to vring_free(), which still calls to_vvq()
> to get 'vq', let's directly pass 'vq'. It can avoid
> unnecessary call of to_vvq() in hot path.
> 
> Signed-off-by: Bo Liu <liubo03@inspur.com>

What is the point of this change?

__vring_new_virtqueue returns struct virtqueue *, so vring_free
matches that. No?

> ---
>  drivers/virtio/virtio_ring.c | 12 +++++-------
>  1 file changed, 5 insertions(+), 7 deletions(-)
> 
> diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c
> index 8974c34b40fd..d6d77bf58802 100644
> --- a/drivers/virtio/virtio_ring.c
> +++ b/drivers/virtio/virtio_ring.c
> @@ -221,7 +221,7 @@ static struct virtqueue *__vring_new_virtqueue(unsigned int index,
>  					       void (*callback)(struct virtqueue *),
>  					       const char *name);
>  static struct vring_desc_extra *vring_alloc_desc_extra(unsigned int num);
> -static void vring_free(struct virtqueue *_vq);
> +static void vring_free(struct vring_virtqueue *vq);
>  
>  /*
>   * Helpers.
> @@ -1140,7 +1140,7 @@ static int virtqueue_resize_split(struct virtqueue *_vq, u32 num)
>  	if (err)
>  		goto err_state_extra;
>  
> -	vring_free(&vq->vq);
> +	vring_free(vq);
>  
>  	virtqueue_vring_init_split(&vring_split, vq);
>  
> @@ -2059,7 +2059,7 @@ static int virtqueue_resize_packed(struct virtqueue *_vq, u32 num)
>  	if (err)
>  		goto err_state_extra;
>  
> -	vring_free(&vq->vq);
> +	vring_free(vq);
>  
>  	virtqueue_vring_init_packed(&vring_packed, !!vq->vq.callback);
>  
> @@ -2649,10 +2649,8 @@ struct virtqueue *vring_new_virtqueue(unsigned int index,
>  }
>  EXPORT_SYMBOL_GPL(vring_new_virtqueue);
>  
> -static void vring_free(struct virtqueue *_vq)
> +static void vring_free(struct vring_virtqueue *vq)
>  {
> -	struct vring_virtqueue *vq = to_vvq(_vq);
> -
>  	if (vq->we_own_ring) {
>  		if (vq->packed_ring) {
>  			vring_free_queue(vq->vq.vdev,
> @@ -2693,7 +2691,7 @@ void vring_del_virtqueue(struct virtqueue *_vq)
>  	list_del(&_vq->list);
>  	spin_unlock(&vq->vq.vdev->vqs_list_lock);
>  
> -	vring_free(_vq);
> +	vring_free(vq);
>  
>  	kfree(vq);
>  }
> -- 
> 2.27.0

Re: [PATCH] virtio_ring: remove unnecessary to_vvq() call

Posted by Jason Wang 3 years, 6 months ago

On Mon, Sep 26, 2022 at 5:11 PM Bo Liu <liubo03@inspur.com> wrote:
>
> It passes '_vq' to vring_free(), which still calls to_vvq()
> to get 'vq', let's directly pass 'vq'. It can avoid
> unnecessary call of to_vvq() in hot path.
>
> Signed-off-by: Bo Liu <liubo03@inspur.com>

Acked-by: Jason Wang <jasowang@redhat.com>

> ---
>  drivers/virtio/virtio_ring.c | 12 +++++-------
>  1 file changed, 5 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c
> index 8974c34b40fd..d6d77bf58802 100644
> --- a/drivers/virtio/virtio_ring.c
> +++ b/drivers/virtio/virtio_ring.c
> @@ -221,7 +221,7 @@ static struct virtqueue *__vring_new_virtqueue(unsigned int index,
>                                                void (*callback)(struct virtqueue *),
>                                                const char *name);
>  static struct vring_desc_extra *vring_alloc_desc_extra(unsigned int num);
> -static void vring_free(struct virtqueue *_vq);
> +static void vring_free(struct vring_virtqueue *vq);
>
>  /*
>   * Helpers.
> @@ -1140,7 +1140,7 @@ static int virtqueue_resize_split(struct virtqueue *_vq, u32 num)
>         if (err)
>                 goto err_state_extra;
>
> -       vring_free(&vq->vq);
> +       vring_free(vq);
>
>         virtqueue_vring_init_split(&vring_split, vq);
>
> @@ -2059,7 +2059,7 @@ static int virtqueue_resize_packed(struct virtqueue *_vq, u32 num)
>         if (err)
>                 goto err_state_extra;
>
> -       vring_free(&vq->vq);
> +       vring_free(vq);
>
>         virtqueue_vring_init_packed(&vring_packed, !!vq->vq.callback);
>
> @@ -2649,10 +2649,8 @@ struct virtqueue *vring_new_virtqueue(unsigned int index,
>  }
>  EXPORT_SYMBOL_GPL(vring_new_virtqueue);
>
> -static void vring_free(struct virtqueue *_vq)
> +static void vring_free(struct vring_virtqueue *vq)
>  {
> -       struct vring_virtqueue *vq = to_vvq(_vq);
> -
>         if (vq->we_own_ring) {
>                 if (vq->packed_ring) {
>                         vring_free_queue(vq->vq.vdev,
> @@ -2693,7 +2691,7 @@ void vring_del_virtqueue(struct virtqueue *_vq)
>         list_del(&_vq->list);
>         spin_unlock(&vq->vq.vdev->vqs_list_lock);
>
> -       vring_free(_vq);
> +       vring_free(vq);
>
>         kfree(vq);
>  }
> --
> 2.27.0
>