virtio_ring: introduce add api for premapped

Two APIs are introduced to submit premapped per-buffers.

int virtqueue_add_inbuf_premapped(struct virtqueue *vq,
                                 struct scatterlist *sg, unsigned int num,
                                 void *data,
                                 void *ctx,
                                 gfp_t gfp);

int virtqueue_add_outbuf_premapped(struct virtqueue *vq,
                                  struct scatterlist *sg, unsigned int num,
                                  void *data,
                                  gfp_t gfp);

Signed-off-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
Acked-by: Jason Wang <jasowang@redhat.com>
Link: https://patch.msgid.link/20241112012928.102478-6-xuanzhuo@linux.alibaba.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

1 files changed, 48 insertions, 0 deletions

diff --git a/drivers/virtio/virtio_ring.c b/drivers/virtio/virtio_ring.c
index fefa85a5e6b6..0842d27886e5 100644
--- a/drivers/virtio/virtio_ring.c
+++ b/drivers/virtio/virtio_ring.c
@@ -2277,6 +2277,29 @@ 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).
+ *
+ * Return:
+ * 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, true, gfp);
+}
+EXPORT_SYMBOL_GPL(virtqueue_add_outbuf_premapped);
+
+/**
  * virtqueue_add_inbuf - expose input buffers to other end
  * @vq: the struct virtqueue we're talking about.
  * @sg: scatterlist (must be well-formed and terminated!)
@@ -2323,6 +2346,31 @@ int virtqueue_add_inbuf_ctx(struct virtqueue *vq,
 EXPORT_SYMBOL_GPL(virtqueue_add_inbuf_ctx);
 
 /**
+ * virtqueue_add_inbuf_premapped - expose input 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 writable by other side
+ * @data: the token identifying the buffer.
+ * @ctx: extra context for the token
+ * @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).
+ *
+ * Return:
+ * Returns zero or a negative error (ie. ENOSPC, ENOMEM, EIO).
+ */
+int virtqueue_add_inbuf_premapped(struct virtqueue *vq,
+				  struct scatterlist *sg, unsigned int num,
+				  void *data,
+				  void *ctx,
+				  gfp_t gfp)
+{
+	return virtqueue_add(vq, &sg, num, 0, 1, data, ctx, true, gfp);
+}
+EXPORT_SYMBOL_GPL(virtqueue_add_inbuf_premapped);
+
+/**
  * virtqueue_dma_dev - get the dma dev
  * @_vq: the struct virtqueue we're talking about.
  *