On Tue, 22 Nov 2011 08:29:08 +0200, "Michael S. Tsirkin" [off-list ref] wrote:

On Tue, Nov 22, 2011 at 11:03:04AM +1030, Rusty Russell wrote:

quoted

-	/* If you haven't kicked in this long, you're probably doing something
-	 * wrong. */
-	WARN_ON(vq->num_added > vq->vring.num);
+	/* This is very unlikely, but theoretically possible.  Kick
+	 * just in case. */
+	if (unlikely(vq->num_added == 65535))

This is 0xffff but why use the decimal notation?

Interesting.  Why use hex?  Feels more like binary?

But I've changed it to "(1 << 16) - 1" to be clear.

quoted

+		virtqueue_kick(_vq);
 
 	pr_debug("Added buffer head %i to %p\n", head, vq);
 	END_USE(vq);

We also still need to reset vq->num_added, right?

virtqueue_kick does that for us.

Cheers,
Rusty.