2024-04-23 03:24:45

by Gavin Shan

[permalink] [raw]
Subject: [PATCH 1/4] vhost: Drop variable last_avail_idx in vhost_get_vq_desc()

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 <[email protected]>
---
drivers/vhost/vhost.c | 15 ++++++---------
1 file changed, 6 insertions(+), 9 deletions(-)

diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
index 8995730ce0bf..ef7942103232 100644
--- a/drivers/vhost/vhost.c
+++ b/drivers/vhost/vhost.c
@@ -2498,14 +2498,11 @@ int vhost_get_vq_desc(struct vhost_virtqueue *vq,
{
struct vring_desc desc;
unsigned int i, head, found = 0;
- u16 last_avail_idx;
__virtio16 avail_idx;
__virtio16 ring_head;
int ret, access;

/* Check it isn't doing very strange things with descriptor numbers. */
- last_avail_idx = vq->last_avail_idx;
-
if (vq->avail_idx == vq->last_avail_idx) {
if (unlikely(vhost_get_avail_idx(vq, &avail_idx))) {
vq_err(vq, "Failed to access avail idx at %p\n",
@@ -2514,16 +2511,16 @@ int vhost_get_vq_desc(struct vhost_virtqueue *vq,
}
vq->avail_idx = vhost16_to_cpu(vq, avail_idx);

- if (unlikely((u16)(vq->avail_idx - last_avail_idx) > vq->num)) {
+ if (unlikely((u16)(vq->avail_idx - vq->last_avail_idx) > vq->num)) {
vq_err(vq, "Guest moved avail index from %u to %u",
- last_avail_idx, vq->avail_idx);
+ vq->last_avail_idx, vq->avail_idx);
return -EFAULT;
}

/* If there's nothing new since last we looked, return
* invalid.
*/
- if (vq->avail_idx == last_avail_idx)
+ if (vq->avail_idx == vq->last_avail_idx)
return vq->num;

/* Only get avail ring entries after they have been
@@ -2534,10 +2531,10 @@ 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;
}

--
2.44.0