From ebf9a5a99c1a464afe0b4dfa64416fc8b273bc5c Mon Sep 17 00:00:00 2001 From: Rusty Russell Date: Fri, 12 Jun 2009 22:27:01 -0600 Subject: [PATCH] lguest: remove invalid interrupt forcing logic. 20887611523e749d99cc7d64ff6c97d27529fbae (lguest: notify on empty) introduced lguest support for the VIRTIO_F_NOTIFY_ON_EMPTY flag, but in fact it turned on interrupts all the time. Because we always process one buffer at a time, the inflight count is always 0 when call trigger_irq and so we always ignore VRING_AVAIL_F_NO_INTERRUPT from the Guest. It should be looking to see if there are more buffers in the Guest's queue: if it's empty, then we force an interrupt. This makes little difference, since we usually have an empty queue; but that's the subject of another patch. Signed-off-by: Rusty Russell --- Documentation/lguest/lguest.c | 8 +------- 1 file changed, 1 insertion(+), 7 deletions(-) diff --git a/Documentation/lguest/lguest.c b/Documentation/lguest/lguest.c index 1e31d1ec12a3..9f3240c45718 100644 --- a/Documentation/lguest/lguest.c +++ b/Documentation/lguest/lguest.c @@ -172,9 +172,6 @@ struct virtqueue /* The routine to call when the Guest pings us, or timeout. */ void (*handle_output)(struct virtqueue *me, bool timeout); - /* Outstanding buffers */ - unsigned int inflight; - /* Is this blocked awaiting a timer? */ bool blocked; }; @@ -699,7 +696,6 @@ static unsigned get_vq_desc(struct virtqueue *vq, errx(1, "Looped descriptor"); } while ((i = next_desc(vq, i)) != vq->vring.num); - vq->inflight++; return head; } @@ -717,7 +713,6 @@ 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->inflight--; } /* This actually sends the interrupt for this virtqueue */ @@ -727,7 +722,7 @@ static void trigger_irq(struct virtqueue *vq) /* If they don't want an interrupt, don't send one, unless empty. */ if ((vq->vring.avail->flags & VRING_AVAIL_F_NO_INTERRUPT) - && vq->inflight) + && lg_last_avail(vq) != vq->vring.avail->idx) return; /* Send the Guest an interrupt tell them we used something up. */ @@ -1171,7 +1166,6 @@ static void add_virtqueue(struct device *dev, unsigned int num_descs, vq->next = NULL; vq->last_avail_idx = 0; vq->dev = dev; - vq->inflight = 0; vq->blocked = false; /* Initialize the configuration. */ -- GitLab