Subject: virtio: return correct capacity to users Date: Thu, 4 Nov 2010 14:24:24 +0200 From: "Michael S. Tsirkin" We can't rely on indirect buffers for capacity calculations because they need a memory allocation which might fail. In particular, virtio_net can get into this situation under stress, and it drops packets and performs badly. So return the number of buffers we can guarantee users. Signed-off-by: Michael S. Tsirkin Signed-off-by: Rusty Russell Reported-By: Krishna Kumar2 --- drivers/virtio/virtio_ring.c | 3 --- 1 file changed, 3 deletions(-) diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c index 1475ed6..cc2f73e 100644 --- a/drivers/virtio/virtio_ring.c +++ b/drivers/virtio/virtio_ring.c @@ -230,9 +230,6 @@ add_head: pr_debug("Added buffer head %i to %p\n", head, vq); END_USE(vq); - /* If we're indirect, we can fit many (assuming not OOM). */ - if (vq->indirect) - return vq->num_free ? vq->vring.num : 0; return vq->num_free; } EXPORT_SYMBOL_GPL(virtqueue_add_buf_gfp);