Improve vhost_get_avail_head() so that the head or errno is returned.
With it, the relevant sanity checks are squeezed to vhost_get_avail_head()
and vhost_get_vq_desc() is further simplified.
No functional change intended.
Signed-off-by: Gavin Shan <gshan@xxxxxxxxxx>
---
drivers/vhost/vhost.c | 43 +++++++++++++++++++++++--------------------
1 file changed, 23 insertions(+), 20 deletions(-)
diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
index b3adc0bc9e72..a3de9325175f 100644
--- a/drivers/vhost/vhost.c
+++ b/drivers/vhost/vhost.c
@@ -1320,11 +1320,27 @@ static inline int vhost_get_avail_idx(struct vhost_virtqueue *vq)
return 0;
}
-static inline int vhost_get_avail_head(struct vhost_virtqueue *vq,
- __virtio16 *head, int idx)
+static inline int vhost_get_avail_head(struct vhost_virtqueue *vq)
{
- return vhost_get_avail(vq, *head,
- &vq->avail->ring[idx & (vq->num - 1)]);
+ __virtio16 head;
+ int r;
+
+ r = vhost_get_avail(vq, head,
+ &vq->avail->ring[vq->last_avail_idx & (vq->num - 1)]);
+ if (unlikely(r)) {
+ vq_err(vq, "Failed to read head: idx %u address %p\n",
+ vq->last_avail_idx,
+ &vq->avail->ring[vq->last_avail_idx % vq->num]);
+ return r;
+ }
+
+ r = vhost16_to_cpu(vq, head);
+ if (unlikely(r >= vq->num)) {
+ vq_err(vq, "Invalid head %d (%u)\n", r, vq->num);
+ return -EINVAL;
+ }
+
+ return r;
}
static inline int vhost_get_avail_flags(struct vhost_virtqueue *vq,
@@ -2522,7 +2538,6 @@ int vhost_get_vq_desc(struct vhost_virtqueue *vq,
{
struct vring_desc desc;
unsigned int i, head, found = 0;
- __virtio16 ring_head;
int ret, access;
if (vq->avail_idx == vq->last_avail_idx) {
@@ -2539,21 +2554,9 @@ 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, vq->last_avail_idx))) {
- vq_err(vq, "Failed to read head: idx %d address %p\n",
- vq->last_avail_idx,
- &vq->avail->ring[vq->last_avail_idx % vq->num]);
- return -EFAULT;
- }
-
- head = vhost16_to_cpu(vq, ring_head);
-
- /* If their number is silly, that's an error. */
- if (unlikely(head >= vq->num)) {
- vq_err(vq, "Guest says index %u > %u is available",
- head, vq->num);
- return -EINVAL;
- }
+ head = vhost_get_avail_head(vq);
+ if (unlikely(head < 0))
+ return head;
/* When we start there are none of either input nor output. */
*out_num = *in_num = 0;
--
2.44.0
