vhost: optimize interrupt enable/disable

RFC PATCH New Michael S. Tsirkin 1 participant 1 message Jul 19, 2011

Subsystems (4)

Networking Network drivers KVM virtio host (vhost)

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Michael S. Tsirkin

author maintainer

2011-07-19 15:04 UTC #0 lore raw

RFC PATCH 1/1 vhost: optimize interrupt enable/disable

As we now only update used ring after enabling
the backend, we can write flags with __put_user:
as that's done on data path, it matters.

Signed-off-by Michael S. Tsirkin <[email protected]>

---

It seems an obvious optimization so I queued this up already.

 drivers/vhost/vhost.c |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)

drivers/vhost/vhost.c +2 -2

index c16d225..c14c42b 100644
@@ -998,7 +998,7 @@ int vhost_log_write(struct vhost_virtqueue *vq, struct vhost_log *log,
 static int vhost_update_used_flags(struct vhost_virtqueue *vq)
 {
 	void __user *used;
-	if (put_user(vq->used_flags, &vq->used->flags) < 0)
+	if (__put_user(vq->used_flags, &vq->used->flags) < 0)
 		return -EFAULT;
 	if (unlikely(vq->log_used)) {
 		/* Make sure the flag is seen before log. */

@@ -1016,7 +1016,7 @@ static int vhost_update_used_flags(struct vhost_virtqueue *vq)
 
 static int vhost_update_avail_event(struct vhost_virtqueue *vq, u16 avail_event)
 {
-	if (put_user(vq->avail_idx, vhost_avail_event(vq)))
+	if (__put_user(vq->avail_idx, vhost_avail_event(vq)))
 		return -EFAULT;
 	if (unlikely(vq->log_used)) {
 		void __user *used;

Signature · 1 line

1.7.5.53.gc233e