virtio_ring: add virtqueue_add_inbuf/outbuf_rpmsg API

Expose new variants of virtqueue_add_inbuf() & virtqueue_add_outbuf() API specifically to deal with virtio_rpmsg. The virtio core in general expects all the vring buffers to be allocated from linear addresses, but the virtio_rpmsg can have the buffers in non-linear space due to its usage of the dma_alloc_coherent() API. Based on a RFC patch from Edgar E. Iglesias <edgar.iglesias@xilinx.com>, http://marc.info/?l=linux-virtualization&m=143047902512226&w=2 Signed-off-by: Suman Anna <s-anna@ti.com>

virtio_ring: add virtqueue_add_inbuf/outbuf_rpmsg API
Expose new variants of virtqueue_add_inbuf() & virtqueue_add_outbuf() API specifically to deal with virtio_rpmsg. The virtio core in general expects all the vring buffers to be allocated from linear addresses, but the virtio_rpmsg can have the buffers in non-linear space due to its usage of the dma_alloc_coherent() API. Based on a RFC patch from Edgar E. Iglesias <edgar.iglesias@xilinx.com>, http://marc.info/?l=linux-virtualization&m=143047902512226&w=2 Signed-off-by: Suman Anna <s-anna@ti.com>
Suman Anna
1 parent 13d7a146c7
Showing 2 changed files with 60 additions and 0 deletions Side-by-side Diff
drivers/virtio/virtio_ring.c
include/linux/virtio.h
@@ -324,6 +324,31 @@
 EXPORT_SYMBOL_GPL(virtqueue_add_outbuf);
  
 /**
+ * virtqueue_add_outbuf_rpmsg - expose output buffers for virtio_rpmsg
+ * @vq: the struct virtqueue we're talking about.
+ * @sg: scatterlist (with dma fields filled in, and terminated properly!)
+ * @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). Note that the scatterlist is
+ * non-standard with only the corresponding dma fields filled in, so
+ * should not be used with any sg operations using traditional buffer
+ * and length fields.
+ *
+ * Returns zero or a negative error (ie. ENOSPC, ENOMEM, EIO).
+ */
+int virtqueue_add_outbuf_rpmsg(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(virtqueue_add_outbuf_rpmsg);
+
+/**
  * 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!)
@@ -344,6 +369,31 @@
 	return virtqueue_add(vq, &sg, num, 0, 1, data, gfp, false);
 }
 EXPORT_SYMBOL_GPL(virtqueue_add_inbuf);
+
+/**
+ * virtqueue_add_inbuf_rpmsg - expose input buffers for virtio_rpmsg
+ * @vq: the struct virtqueue we're talking about.
+ * @sg: scatterlist (with dma fields filled in, and terminated properly!)
+ * @num: the number of entries in @sg writable 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). Note that the scatterlist is
+ * non-standard with only the corresponding dma fields filled in, so
+ * should not be used with any sg operations using traditional buffer
+ * and length fields.
+ *
+ * Returns zero or a negative error (ie. ENOSPC, ENOMEM, EIO).
+ */
+int virtqueue_add_inbuf_rpmsg(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(virtqueue_add_inbuf_rpmsg);
  
 /**
  * virtqueue_kick_prepare - first half of split virtqueue_kick call.
@@ -44,6 +44,16 @@
 			void *data,
 			gfp_t gfp);
  
+int virtqueue_add_outbuf_rpmsg(struct virtqueue *vq,
+			       struct scatterlist sg[], unsigned int num,
+			       void *data,
+			       gfp_t gfp);
+
+int virtqueue_add_inbuf_rpmsg(struct virtqueue *vq,
+			      struct scatterlist sg[], unsigned int num,
+			      void *data,
+			      gfp_t gfp);
+
 int virtqueue_add_sgs(struct virtqueue *vq,
 		      struct scatterlist *sgs[],
 		      unsigned int out_sgs,
...	...	@@ -324,6 +324,31 @@
324	324	EXPORT_SYMBOL_GPL(virtqueue_add_outbuf);
325	325
326	326	/**
	327	+ * virtqueue_add_outbuf_rpmsg - expose output buffers for virtio_rpmsg
	328	+ * @vq: the struct virtqueue we're talking about.
	329	+ * @sg: scatterlist (with dma fields filled in, and terminated properly!)
	330	+ * @num: the number of entries in @sg readable by other side
	331	+ * @data: the token identifying the buffer.
	332	+ * @gfp: how to do memory allocations (if necessary).
	333	+ *
	334	+ * Caller must ensure we don't call this with other virtqueue operations
	335	+ * at the same time (except where noted). Note that the scatterlist is
	336	+ * non-standard with only the corresponding dma fields filled in, so
	337	+ * should not be used with any sg operations using traditional buffer
	338	+ * and length fields.
	339	+ *
	340	+ * Returns zero or a negative error (ie. ENOSPC, ENOMEM, EIO).
	341	+ */
	342	+int virtqueue_add_outbuf_rpmsg(struct virtqueue *vq,
	343	+ struct scatterlist *sg, unsigned int num,
	344	+ void *data,
	345	+ gfp_t gfp)
	346	+{
	347	+ return virtqueue_add(vq, &sg, num, 1, 0, data, gfp, true);
	348	+}
	349	+EXPORT_SYMBOL_GPL(virtqueue_add_outbuf_rpmsg);
	350	+
	351	+/**
327	352	* virtqueue_add_inbuf - expose input buffers to other end
328	353	* @vq: the struct virtqueue we're talking about.
329	354	* @sg: scatterlist (must be well-formed and terminated!)
...	...	@@ -344,6 +369,31 @@
344	369	return virtqueue_add(vq, &sg, num, 0, 1, data, gfp, false);
345	370	}
346	371	EXPORT_SYMBOL_GPL(virtqueue_add_inbuf);
	372	+
	373	+/**
	374	+ * virtqueue_add_inbuf_rpmsg - expose input buffers for virtio_rpmsg
	375	+ * @vq: the struct virtqueue we're talking about.
	376	+ * @sg: scatterlist (with dma fields filled in, and terminated properly!)
	377	+ * @num: the number of entries in @sg writable by other side
	378	+ * @data: the token identifying the buffer.
	379	+ * @gfp: how to do memory allocations (if necessary).
	380	+ *
	381	+ * Caller must ensure we don't call this with other virtqueue operations
	382	+ * at the same time (except where noted). Note that the scatterlist is
	383	+ * non-standard with only the corresponding dma fields filled in, so
	384	+ * should not be used with any sg operations using traditional buffer
	385	+ * and length fields.
	386	+ *
	387	+ * Returns zero or a negative error (ie. ENOSPC, ENOMEM, EIO).
	388	+ */
	389	+int virtqueue_add_inbuf_rpmsg(struct virtqueue *vq,
	390	+ struct scatterlist *sg, unsigned int num,
	391	+ void *data,
	392	+ gfp_t gfp)
	393	+{
	394	+ return virtqueue_add(vq, &sg, num, 0, 1, data, gfp, true);
	395	+}
	396	+EXPORT_SYMBOL_GPL(virtqueue_add_inbuf_rpmsg);
347	397
348	398	/**
349	399	* virtqueue_kick_prepare - first half of split virtqueue_kick call.
...	...	@@ -44,6 +44,16 @@
44	44	void *data,
45	45	gfp_t gfp);
46	46
	47	+int virtqueue_add_outbuf_rpmsg(struct virtqueue *vq,
	48	+ struct scatterlist sg[], unsigned int num,
	49	+ void *data,
	50	+ gfp_t gfp);
	51	+
	52	+int virtqueue_add_inbuf_rpmsg(struct virtqueue *vq,
	53	+ struct scatterlist sg[], unsigned int num,
	54	+ void *data,
	55	+ gfp_t gfp);
	56	+
47	57	int virtqueue_add_sgs(struct virtqueue *vq,
48	58	struct scatterlist *sgs[],
49	59	unsigned int out_sgs,