skbuff: struct ubuf_info callback type safety

The skb struct ubuf_info callback gets passed struct ubuf_info
itself, not the arg value as the field name and the function signature
seem to imply. Rename the arg field to ctx to match usage,
add documentation and change the callback argument type
to make usage clear and to have compiler check correctness.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 2 insertions, 3 deletions

diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
index 947f00d8e091..51e4c1eeec4f 100644
--- a/drivers/vhost/vhost.c
+++ b/drivers/vhost/vhost.c
@@ -1598,10 +1598,9 @@ void vhost_ubuf_put_and_wait(struct vhost_ubuf_ref *ubufs)
         kfree(ubufs);
 }
 
-void vhost_zerocopy_callback(void *arg)
+void vhost_zerocopy_callback(struct ubuf_info *ubuf)
 {
-        struct ubuf_info *ubuf = arg;
-        struct vhost_ubuf_ref *ubufs = ubuf->arg;
+        struct vhost_ubuf_ref *ubufs = ubuf->ctx;
         struct vhost_virtqueue *vq = ubufs->vq;
 
         /* set len = 1 to mark this desc buffers done DMA */