dma-buf: cleanup dma_buf_export() to make it easily extensible

At present, dma_buf_export() takes a series of parameters, which
makes it difficult to add any new parameters for exporters, if required.

Make it simpler by moving all these parameters into a struct, and pass
the struct * as parameter to dma_buf_export().

While at it, unite dma_buf_export_named() with dma_buf_export(), and
change all callers accordingly.

Reviewed-by: Maarten Lankhorst <maarten.lankhorst@canonical.com>
Reviewed-by: Daniel Thompson <daniel.thompson@linaro.org>
Acked-by: Mauro Carvalho Chehab <mchehab@osg.samsung.com>
Acked-by: Dave Airlie <airlied@redhat.com>
Signed-off-by: Sumit Semwal <sumit.semwal@linaro.org>

drivers/dma-buf/dma-buf.c

@@ -265,43 +265,40 @@ static inline int is_dma_buf_file(struct file *file)
 }
 
 /**
- * dma_buf_export_named - Creates a new dma_buf, and associates an anon file
+ * dma_buf_export - Creates a new dma_buf, and associates an anon file
  * with this buffer, so it can be exported.
  * Also connect the allocator specific data and ops to the buffer.
  * Additionally, provide a name string for exporter; useful in debugging.
  *
- * @priv:	[in]	Attach private data of allocator to this buffer
- * @ops:	[in]	Attach allocator-defined dma buf ops to the new buffer.
- * @size:	[in]	Size of the buffer
- * @flags:	[in]	mode flags for the file.
- * @exp_name:	[in]	name of the exporting module - useful for debugging.
- * @resv:	[in]	reservation-object, NULL to allocate default one.
+ * @exp_info:	[in]	holds all the export related information provided
+ *			by the exporter. see struct dma_buf_export_info
+ *			for further details.
  *
  * Returns, on success, a newly created dma_buf object, which wraps the
  * supplied private data and operations for dma_buf_ops. On either missing
  * ops, or error in allocating struct dma_buf, will return negative error.
  *
  */
-struct dma_buf *dma_buf_export_named(void *priv, const struct dma_buf_ops *ops,
-				size_t size, int flags, const char *exp_name,
-				struct reservation_object *resv)
+struct dma_buf *dma_buf_export(const struct dma_buf_export_info *exp_info)
 {
 	struct dma_buf *dmabuf;
+	struct reservation_object *resv = exp_info->resv;
 	struct file *file;
 	size_t alloc_size = sizeof(struct dma_buf);
-	if (!resv)
+	if (!exp_info->resv)
 		alloc_size += sizeof(struct reservation_object);
 	else
 		/* prevent &dma_buf[1] == dma_buf->resv */
 		alloc_size += 1;
 
-	if (WARN_ON(!priv || !ops
-			  || !ops->map_dma_buf
-			  || !ops->unmap_dma_buf
-			  || !ops->release
-			  || !ops->kmap_atomic
-			  || !ops->kmap
-			  || !ops->mmap)) {
+	if (WARN_ON(!exp_info->priv
+			  || !exp_info->ops
+			  || !exp_info->ops->map_dma_buf
+			  || !exp_info->ops->unmap_dma_buf
+			  || !exp_info->ops->release
+			  || !exp_info->ops->kmap_atomic
+			  || !exp_info->ops->kmap
+			  || !exp_info->ops->mmap)) {
 		return ERR_PTR(-EINVAL);
 	}
 
@@ -309,10 +306,10 @@ struct dma_buf *dma_buf_export_named(void *priv, const struct dma_buf_ops *ops,
 	if (dmabuf == NULL)
 		return ERR_PTR(-ENOMEM);
 
-	dmabuf->priv = priv;
-	dmabuf->ops = ops;
-	dmabuf->size = size;
-	dmabuf->exp_name = exp_name;
+	dmabuf->priv = exp_info->priv;
+	dmabuf->ops = exp_info->ops;
+	dmabuf->size = exp_info->size;
+	dmabuf->exp_name = exp_info->exp_name;
 	init_waitqueue_head(&dmabuf->poll);
 	dmabuf->cb_excl.poll = dmabuf->cb_shared.poll = &dmabuf->poll;
 	dmabuf->cb_excl.active = dmabuf->cb_shared.active = 0;
@@ -323,7 +320,8 @@ struct dma_buf *dma_buf_export_named(void *priv, const struct dma_buf_ops *ops,
 	}
 	dmabuf->resv = resv;
 
-	file = anon_inode_getfile("dmabuf", &dma_buf_fops, dmabuf, flags);
+	file = anon_inode_getfile("dmabuf", &dma_buf_fops, dmabuf,
+					exp_info->flags);
 	if (IS_ERR(file)) {
 		kfree(dmabuf);
 		return ERR_CAST(file);
@@ -341,8 +339,7 @@ struct dma_buf *dma_buf_export_named(void *priv, const struct dma_buf_ops *ops,
 
 	return dmabuf;
 }
-EXPORT_SYMBOL_GPL(dma_buf_export_named);
-
+EXPORT_SYMBOL_GPL(dma_buf_export);
 
 /**
  * dma_buf_fd - returns a file descriptor for the given dma_buf