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authorAmit Shah <amit.shah@redhat.com>2011-03-16 19:12:10 +0530
committerRusty Russell <rusty@rustcorp.com.au>2011-04-21 22:57:00 +0930
commitb3258ff1d6086bd2b9eeb556844a868ad7d49bc8 (patch)
tree2c9dde005804227038c997a983ded7e46951ca64 /drivers/virtio
parent584f79046780e10cb24367a691f8c28398a00e84 (diff)
virtio: Decrement avail idx on buffer detach
When detaching a buffer from a vq, the avail.idx value should be decremented as well. This was noticed by hot-unplugging a virtio console port and then plugging in a new one on the same number (re-using the vqs which were just 'disowned'). qemu reported 'Guest moved used index from 0 to 256' when any IO was attempted on the new port. CC: stable@kernel.org Reported-by: juzhang <juzhang@redhat.com> Signed-off-by: Amit Shah <amit.shah@redhat.com> Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Diffstat (limited to 'drivers/virtio')
-rw-r--r--drivers/virtio/virtio_ring.c1
1 files changed, 1 insertions, 0 deletions
diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c
index cc2f73e0347..b0043fb26a4 100644
--- a/drivers/virtio/virtio_ring.c
+++ b/drivers/virtio/virtio_ring.c
@@ -371,6 +371,7 @@ void *virtqueue_detach_unused_buf(struct virtqueue *_vq)
/* detach_buf clears data, so grab it now. */
buf = vq->data[i];
detach_buf(vq, i);
+ vq->vring.avail->idx--;
END_USE(vq);
return buf;
}