Re: [PATCH 5 of 5] virtio: expose added descriptors immediately
From: "Michael S. Tsirkin" <mst@redhat.com>
Date: 2011-11-23 08:28:44
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On Wed, Nov 23, 2011 at 11:49:01AM +1030, Rusty Russell wrote:
On Tue, 22 Nov 2011 08:29:08 +0200, "Michael S. Tsirkin" [off-list ref] wrote:quoted
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?
Just easier to see it's the largest 16 bit number.
But I've changed it to "(1 << 16) - 1" to be clear.
That's even better.
quoted
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.
Right.