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authorRusty Russell <rusty@rustcorp.com.au>2009-06-13 06:27:01 +0200
committerRusty Russell <rusty@rustcorp.com.au>2009-06-12 14:57:02 +0200
commitebf9a5a99c1a464afe0b4dfa64416fc8b273bc5c (patch)
treeb5f0631172db5d97e0a5c6b8a6bc0f83c4a4eed5
parentlguest: fix lguest wake on guest clock tick, or fd activity (diff)
downloadlinux-ebf9a5a99c1a464afe0b4dfa64416fc8b273bc5c.tar.xz
linux-ebf9a5a99c1a464afe0b4dfa64416fc8b273bc5c.zip
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 <rusty@rustcorp.com.au>
-rw-r--r--Documentation/lguest/lguest.c8
1 files changed, 1 insertions, 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. */