Commit 2df64759 authored by Xuan Zhuo's avatar Xuan Zhuo Committed by Michael S. Tsirkin
Browse files

virtio_ring: introduce virtqueue_dma_dev() 



Added virtqueue_dma_dev() to get DMA device for virtio. Then the
caller can do dma operation in advance. The purpose is to keep memory
mapped across multiple add/get buf operations.

Signed-off-by: default avatarXuan Zhuo <xuanzhuo@linux.alibaba.com>
Acked-by: default avatarJason Wang <jasowang@redhat.com>
Message-Id: <20230810123057.43407-6-xuanzhuo@linux.alibaba.com>
Signed-off-by: default avatarMichael S. Tsirkin <mst@redhat.com>
parent d7344a2f

drivers/virtio/virtio_ring.c

+17 −0
Original line number Diff line number Diff line
@@ -2265,6 +2265,23 @@ int virtqueue_add_inbuf_ctx(struct virtqueue *vq, 
}

EXPORT_SYMBOL_GPL(virtqueue_add_inbuf_ctx);



/**

 * virtqueue_dma_dev - get the dma dev

 * @_vq: the struct virtqueue we're talking about.

 *

 * Returns the dma dev. That can been used for dma api.

 */

struct device *virtqueue_dma_dev(struct virtqueue *_vq)

{

	struct vring_virtqueue *vq = to_vvq(_vq);



	if (vq->use_dma_api)

		return vring_dma_dev(vq);

	else

		return NULL;

}

EXPORT_SYMBOL_GPL(virtqueue_dma_dev);



/**

 * virtqueue_kick_prepare - first half of split virtqueue_kick call.

 * @_vq: the struct virtqueue

include/linux/virtio.h

+2 −0
Original line number Diff line number Diff line
@@ -61,6 +61,8 @@ int virtqueue_add_sgs(struct virtqueue *vq, 
		      void *data,

		      gfp_t gfp);



struct device *virtqueue_dma_dev(struct virtqueue *vq);



bool virtqueue_kick(struct virtqueue *vq);



bool virtqueue_kick_prepare(struct virtqueue *vq);