On 4/30/24 04:45, Michael S. Tsirkin wrote:
On Mon, Apr 29, 2024 at 08:13:58PM +1000, Gavin Shan wrote:The local variable @last_avail_idx is equivalent to vq->last_avail_idx. So the code can be simplified a bit by dropping the local variable @last_avail_idx. No functional change intended. Signed-off-by: Gavin Shan <gshan@xxxxxxxxxx> --- drivers/vhost/vhost.c | 7 +++---- 1 file changed, 3 insertions(+), 4 deletions(-) diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c index 7aa623117aab..b278c0333a66 100644 --- a/drivers/vhost/vhost.c +++ b/drivers/vhost/vhost.c @@ -2524,7 +2524,6 @@ int vhost_get_vq_desc(struct vhost_virtqueue *vq, { struct vring_desc desc; unsigned int i, head, found = 0; - u16 last_avail_idx = vq->last_avail_idx; __virtio16 ring_head; int ret, access;@@ -2539,10 +2538,10 @@ int vhost_get_vq_desc(struct vhost_virtqueue *vq, /* Grab the next descriptor number they're advertising, and increment* the index we've seen. */ - if (unlikely(vhost_get_avail_head(vq, &ring_head, last_avail_idx))) { + if (unlikely(vhost_get_avail_head(vq, &ring_head, vq->last_avail_idx))) { vq_err(vq, "Failed to read head: idx %d address %p\n", - last_avail_idx, - &vq->avail->ring[last_avail_idx % vq->num]); + vq->last_avail_idx, + &vq->avail->ring[vq->last_avail_idx % vq->num]); return -EFAULT; }I don't see the big advantage and the line is long now.
The point is to avoid the local variable @last_avail_idx since it's equivalent to vq->last_avail_idx, as stated in the commit log. Besides, it paves the way for PATCH[v2 3/4] where the whole logic fetching the head and sanity check is moved to vhost_get_avail_head(), so that vhost_get_vq_desc() is simplified I will drop PATCH[2, 3, 4] as you suggested. Thanks, Gavin
