[RFC 3/4] virtio: Add dma variants of virtqueue_add_in and outbuf

["Edgar E. Iglesias" <edgar.iglesias@gmail.com>]

From: "Edgar E. Iglesias" <edgar.iglesias@xilinx.com>

Signed-off-by: Edgar E. Iglesias <edgar.iglesias@xilinx.com>
---
 drivers/virtio/virtio_ring.c | 18 ++++++++++++++++++
 include/linux/virtio.h       | 10 ++++++++++
 2 files changed, 28 insertions(+)

diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c
index 233f3c6..dd6c640 100644
--- a/drivers/virtio/virtio_ring.c
+++ b/drivers/virtio/virtio_ring.c
@@ -323,6 +323,15 @@ int virtqueue_add_outbuf(struct virtqueue *vq,
 }
 EXPORT_SYMBOL_GPL(virtqueue_add_outbuf);
 
+int dma_virtqueue_add_outbuf(struct virtqueue *vq,
+			     struct scatterlist *sg, unsigned int num,
+			     void *data,
+			     gfp_t gfp)
+{
+	return virtqueue_add(vq, &sg, num, 1, 0, data, gfp, true);
+}
+EXPORT_SYMBOL_GPL(dma_virtqueue_add_outbuf);
+
 /**
  * virtqueue_add_inbuf - expose input buffers to other end
  * @vq: the struct virtqueue we're talking about.
@@ -345,6 +354,15 @@ int virtqueue_add_inbuf(struct virtqueue *vq,
 }
 EXPORT_SYMBOL_GPL(virtqueue_add_inbuf);
 
+int dma_virtqueue_add_inbuf(struct virtqueue *vq,
+			    struct scatterlist *sg, unsigned int num,
+			    void *data,
+			    gfp_t gfp)
+{
+	return virtqueue_add(vq, &sg, num, 0, 1, data, gfp, true);
+}
+EXPORT_SYMBOL_GPL(dma_virtqueue_add_inbuf);
+
 /**
  * virtqueue_kick_prepare - first half of split virtqueue_kick call.
  * @vq: the struct virtqueue
diff --git a/include/linux/virtio.h b/include/linux/virtio.h
index 8f4d4bf..c31b3e2 100644
--- a/include/linux/virtio.h
+++ b/include/linux/virtio.h
@@ -34,6 +34,16 @@ struct virtqueue {
 	void *priv;
 };
 
+int dma_virtqueue_add_outbuf(struct virtqueue *vq,
+			     struct scatterlist sg[], unsigned int num,
+			     void *data,
+			     gfp_t gfp);
+
+int dma_virtqueue_add_inbuf(struct virtqueue *vq,
+			    struct scatterlist sg[], unsigned int num,
+			    void *data,
+			    gfp_t gfp);
+
 int virtqueue_add_outbuf(struct virtqueue *vq,
 			 struct scatterlist sg[], unsigned int num,
 			 void *data,
-- 
1.9.1