[PATCH vhost v2 08/12] virtio_ring: update document for virtqueue_add_*

Xuan Zhuo
2023-03-08T06:44:39Z

Update the document of virtqueue_add_* series API, allowing the callers to
use sg->dma_address to pass the dma address to Virtio Core.

Signed-off-by: Xuan Zhuo <xuanzhuo at linux.alibaba.com>
---
 drivers/virtio/virtio_ring.c | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)

diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c
index b23d301effb5..216ac8654982 100644
--- a/drivers/virtio/virtio_ring.c
+++ b/drivers/virtio/virtio_ring.c
@@ -2190,6 +2190,10 @@ static inline int virtqueue_add(struct virtqueue *_vq,
  * Caller must ensure we don't call this with other virtqueue operations
  * at the same time (except where noted).
  *
+ * If the caller has done dma map then use sg->dma_address to pass dma
address.
+ * If one sg->dma_address is used, then all sgs must use sg->dma_address;
+ * otherwise all sg->dma_address must be NULL.
+ *
  * Returns zero or a negative error (ie. ENOSPC, ENOMEM, EIO).
  */
 int virtqueue_add_sgs(struct virtqueue *_vq,
@@ -2224,6 +2228,10 @@ EXPORT_SYMBOL_GPL(virtqueue_add_sgs);
  * Caller must ensure we don't call this with other virtqueue operations
  * at the same time (except where noted).
  *
+ * If the caller has done dma map then use sg->dma_address to pass dma
address.
+ * If one sg->dma_address is used, then all sgs must use sg->dma_address;
+ * otherwise all sg->dma_address must be NULL.
+ *
  * Returns zero or a negative error (ie. ENOSPC, ENOMEM, EIO).
  */
 int virtqueue_add_outbuf(struct virtqueue *vq,
@@ -2246,6 +2254,10 @@ EXPORT_SYMBOL_GPL(virtqueue_add_outbuf);
  * Caller must ensure we don't call this with other virtqueue operations
  * at the same time (except where noted).
  *
+ * If the caller has done dma map then use sg->dma_address to pass dma
address.
+ * If one sg->dma_address is used, then all sgs must use sg->dma_address;
+ * otherwise all sg->dma_address must be NULL.
+ *
  * Returns zero or a negative error (ie. ENOSPC, ENOMEM, EIO).
  */
 int virtqueue_add_inbuf(struct virtqueue *vq,
@@ -2269,6 +2281,10 @@ EXPORT_SYMBOL_GPL(virtqueue_add_inbuf);
  * Caller must ensure we don't call this with other virtqueue operations
  * at the same time (except where noted).
  *
+ * If the caller has done dma map then use sg->dma_address to pass dma
address.
+ * If one sg->dma_address is used, then all sgs must use sg->dma_address;
+ * otherwise all sg->dma_address must be NULL.
+ *
  * Returns zero or a negative error (ie. ENOSPC, ENOMEM, EIO).
  */
 int virtqueue_add_inbuf_ctx(struct virtqueue *vq,
--
2.32.0.3.g01195cf9f