Introduce virtqueue_add_outbuf_premapped() to submit premapped sgs.
Signed-off-by: Xuan Zhuo <xuanzhuo@xxxxxxxxxxxxxxxxx>
---
drivers/virtio/virtio_ring.c | 25 +++++++++++++++++++++++++
include/linux/virtio.h | 5 +++++
2 files changed, 30 insertions(+)
diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c
index 6a1e0ef5498a..a76615aca2fd 100644
--- a/drivers/virtio/virtio_ring.c
+++ b/drivers/virtio/virtio_ring.c
@@ -1910,6 +1910,31 @@ int virtqueue_add_outbuf(struct virtqueue *vq,
}
EXPORT_SYMBOL_GPL(virtqueue_add_outbuf);
+/**
+ * virtqueue_add_outbuf_premapped - expose output buffers to other end
+ * @vq: the struct virtqueue we're talking about.
+ * @sg: scatterlist (must be well-formed and terminated!)
+ * @num: the number of entries in @sg readable by other side
+ * @data: the token identifying the buffer.
+ * @gfp: how to do memory allocations (if necessary).
+ *
+ * Caller must ensure we don't call this with other virtqueue operations
+ * at the same time (except where noted).
+ *
+ * It is required that all addrs have completed DMA operations. And use
+ * sg->dma_address, sg->length to pass addr and length.
+ *
+ * Returns zero or a negative error (ie. ENOSPC, ENOMEM, EIO).
+ */
+int virtqueue_add_outbuf_premapped(struct virtqueue *vq,
+ struct scatterlist *sg, unsigned int num,
+ void *data,
+ gfp_t gfp)
+{
+ return virtqueue_add(vq, &sg, num, 1, 0, data, NULL, gfp, true);
+}
+EXPORT_SYMBOL_GPL(virtqueue_add_outbuf_premapped);
+
/**
* virtqueue_add_inbuf - expose input buffers to other end
* @vq: the struct virtqueue we're talking about.
diff --git a/include/linux/virtio.h b/include/linux/virtio.h
index e86ea3b1a124..dbe5a5f8a1ff 100644
--- a/include/linux/virtio.h
+++ b/include/linux/virtio.h
@@ -40,6 +40,11 @@ int virtqueue_add_outbuf(struct virtqueue *vq,
void *data,
gfp_t gfp);
+int virtqueue_add_outbuf_premapped(struct virtqueue *vq,
+ struct scatterlist *sg, unsigned int num,
+ void *data,
+ gfp_t gfp);
+
int virtqueue_add_inbuf(struct virtqueue *vq,
struct scatterlist sg[], unsigned int num,
void *data,
--
2.31.0
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