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

Bo Liu (刘波)-浪潮信息
2022-09-28T02:26:32Z

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>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?
>

Hi
In function vring_free(), to_vvq() js unnecessary, we can directly pass
struct vring_virtqueue * to avoid this and remove the unnecessary code.

>> ---
>> 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

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