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-rw-r--r--Documentation/lguest/lguest.c9
1 files changed, 9 insertions, 0 deletions
diff --git a/Documentation/lguest/lguest.c b/Documentation/lguest/lguest.c
index 84c471b07c2..20f8253881b 100644
--- a/Documentation/lguest/lguest.c
+++ b/Documentation/lguest/lguest.c
@@ -151,6 +151,9 @@ struct virtqueue
/* Last available index we saw. */
u16 last_avail_idx;
+ /* How many are used since we sent last irq? */
+ unsigned int pending_used;
+
/* Eventfd where Guest notifications arrive. */
int eventfd;
@@ -556,6 +559,11 @@ static void trigger_irq(struct virtqueue *vq)
{
unsigned long buf[] = { LHREQ_IRQ, vq->config.irq };
+ /* Don't inform them if nothing used. */
+ if (!vq->pending_used)
+ return;
+ vq->pending_used = 0;
+
/* If they don't want an interrupt, don't send one, unless empty. */
if ((vq->vring.avail->flags & VRING_AVAIL_F_NO_INTERRUPT)
&& lg_last_avail(vq) != vq->vring.avail->idx)
@@ -647,6 +655,7 @@ static void add_used(struct virtqueue *vq, unsigned int head, int len)
/* Make sure buffer is written before we update index. */
wmb();
vq->vring.used->idx++;
+ vq->pending_used++;
}
/* And here's the combo meal deal. Supersize me! */