From cf94db21905333e610e479688add629397a4b384 Mon Sep 17 00:00:00 2001 From: Cornelia Huck Date: Mon, 8 Apr 2019 14:33:22 +0200 Subject: virtio: Honour 'may_reduce_num' in vring_create_virtqueue vring_create_virtqueue() allows the caller to specify via the may_reduce_num parameter whether the vring code is allowed to allocate a smaller ring than specified. However, the split ring allocation code tries to allocate a smaller ring on allocation failure regardless of what the caller specified. This may cause trouble for e.g. virtio-pci in legacy mode, which does not support ring resizing. (The packed ring code does not resize in any case.) Let's fix this by bailing out immediately in the split ring code if the requested size cannot be allocated and may_reduce_num has not been specified. While at it, fix a typo in the usage instructions. Fixes: 2a2d1382fe9d ("virtio: Add improved queue allocation API") Cc: stable@vger.kernel.org # v4.6+ Signed-off-by: Cornelia Huck Signed-off-by: Michael S. Tsirkin Reviewed-by: Halil Pasic Reviewed-by: Jens Freimann --- drivers/virtio/virtio_ring.c | 2 ++ 1 file changed, 2 insertions(+) (limited to 'drivers/virtio/virtio_ring.c') diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c index 18846afb39da..5df92c308286 100644 --- a/drivers/virtio/virtio_ring.c +++ b/drivers/virtio/virtio_ring.c @@ -882,6 +882,8 @@ static struct virtqueue *vring_create_virtqueue_split( GFP_KERNEL|__GFP_NOWARN|__GFP_ZERO); if (queue) break; + if (!may_reduce_num) + return NULL; } if (!num) -- cgit v1.2.3-59-g8ed1b