@@ -3187,6 +3187,38 @@ int virtqueue_dma_mapping_error(struct virtqueue *_vq, dma_addr_t addr)
}
EXPORT_SYMBOL_GPL(virtqueue_dma_mapping_error);
+/**
+ * virtqueue_dma_map_sg_attrs - map scatterlist addr DMA for _vq
+ * @_vq: the struct virtqueue we're talking about.
+ * @sg: the scatterlist to do dma
+ * @dir: DMA direction
+ * @attrs: DMA Attrs
+ *
+ * The caller calls this to do dma mapping in advance. The sg can be
+ * passed to this _vq when it is in pre-mapped mode.
+ *
+ * Returns zero or a negative error.
+ * 0: success
+ * -ENOMEM: dma map error
+ */
+int virtqueue_dma_map_sg_attrs(struct virtqueue *_vq, struct scatterlist *sg,
+ enum dma_data_direction dir, unsigned long attrs)
+{
+ dma_addr_t addr;
+ int err;
+
+ addr = virtqueue_dma_map_page_attrs(_vq, sg_page(sg), sg->offset,
+ sg->length, dir, attrs);
+ err = virtqueue_dma_mapping_error(_vq, addr);
+ if (err)
+ return err;
+
+ sg->dma_address = addr;
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(virtqueue_dma_map_sg_attrs);
+
/**
* virtqueue_dma_need_sync - check a dma address needs sync
* @_vq: the struct virtqueue we're talking about.
@@ -233,6 +233,9 @@ void virtqueue_dma_unmap_page_attrs(struct virtqueue *_vq, dma_addr_t addr,
unsigned long attrs);
int virtqueue_dma_mapping_error(struct virtqueue *_vq, dma_addr_t addr);
+int virtqueue_dma_map_sg_attrs(struct virtqueue *_vq, struct scatterlist *sg,
+ enum dma_data_direction dir, unsigned long attrs);
+
bool virtqueue_dma_need_sync(struct virtqueue *_vq, dma_addr_t addr);
void virtqueue_dma_sync_single_range_for_cpu(struct virtqueue *_vq, dma_addr_t addr,
unsigned long offset, size_t size,
Introduce a helper to do dma map for scatterlist. That can be used by other drivers. Signed-off-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com> --- drivers/virtio/virtio_ring.c | 32 ++++++++++++++++++++++++++++++++ include/linux/virtio.h | 3 +++ 2 files changed, 35 insertions(+)