Re: [PATCH v12 5/8] virtio-balloon: VIRTIO_BALLOON_F_SG
From: "Michael S. Tsirkin" <mst@redhat.com>
Date: 2017-07-12 13:06:18
On Wed, Jul 12, 2017 at 08:40:18PM +0800, Wei Wang wrote:
quoted hunk
diff --git a/include/linux/virtio.h b/include/linux/virtio.h index 28b0e96..9f27101 100644 --- a/include/linux/virtio.h +++ b/include/linux/virtio.h@@ -57,8 +57,28 @@ int virtqueue_add_sgs(struct virtqueue *vq, void *data, gfp_t gfp); +/* A desc with this init id is treated as an invalid desc */ +#define VIRTQUEUE_DESC_ID_INIT UINT_MAX +int virtqueue_add_chain_desc(struct virtqueue *_vq, + uint64_t addr, + uint32_t len, + unsigned int *head_id, + unsigned int *prev_id, + bool in); + +int virtqueue_add_chain(struct virtqueue *_vq, + unsigned int head, + bool indirect, + struct vring_desc *indirect_desc, + void *data, + void *ctx); + bool virtqueue_kick(struct virtqueue *vq); +bool virtqueue_kick_sync(struct virtqueue *vq); + +bool virtqueue_kick_async(struct virtqueue *vq, wait_queue_head_t wq); + bool virtqueue_kick_prepare(struct virtqueue *vq); bool virtqueue_notify(struct virtqueue *vq);
I don't much care for this API. It does exactly what balloon needs, but at cost of e.g. transparently busy-waiting. Unlikely to be a good fit for anything else. If you don't like my original _first/_next/_last, you will need to come up with something else. -- MST