Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 78df9695 authored by Sumit Semwal's avatar Sumit Semwal
Browse files

dma-buf: replace dma_buf_export() with dma_buf_export_named() 



For debugging purposes, it is useful to have a name-string added
while exporting buffers. Hence, dma_buf_export() is replaced with
dma_buf_export_named(), which additionally takes 'exp_name' as a
parameter.

For backward compatibility, and for lazy exporters who don't wish to
name themselves, a #define dma_buf_export() is also made available,
which adds a __FILE__ instead of 'exp_name'.

Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
  [Thanks for the idea!]
Reviewed-by: default avatarDaniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: default avatarSumit Semwal <sumit.semwal@linaro.org>
parent 5f568865

Documentation/dma-buf-sharing.txt

+11 −2
Original line number Diff line number Diff line
@@ -52,14 +52,23 @@ The dma_buf buffer sharing API usage contains the following steps: 
   associated with this buffer.



   Interface:

      struct dma_buf *dma_buf_export(void *priv, struct dma_buf_ops *ops,

				     size_t size, int flags)

      struct dma_buf *dma_buf_export_named(void *priv, struct dma_buf_ops *ops,

				     size_t size, int flags,

				     const char *exp_name)



   If this succeeds, dma_buf_export allocates a dma_buf structure, and returns a

   pointer to the same. It also associates an anonymous file with this buffer,

   so it can be exported. On failure to allocate the dma_buf object, it returns

   NULL.



   'exp_name' is the name of exporter - to facilitate information while

   debugging.



   Exporting modules which do not wish to provide any specific name may use the

   helper define 'dma_buf_export()', with the same arguments as above, but

   without the last argument; a __FILE__ pre-processor directive will be

   inserted in place of 'exp_name' instead.



2. Userspace gets a handle to pass around to potential buffer-users



   Userspace entity requests for a file-descriptor (fd) which is a handle to the

drivers/base/dma-buf.c

+7 −4
Original line number Diff line number Diff line
@@ -77,22 +77,24 @@ static inline int is_dma_buf_file(struct file *file) 
}



/**

 * dma_buf_export - Creates a new dma_buf, and associates an anon file

 * dma_buf_export_named - 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.

 *

 * 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(void *priv, const struct dma_buf_ops *ops,

				size_t size, int flags)

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 dma_buf *dmabuf;

	struct file *file;
@@ -114,6 +116,7 @@ struct dma_buf *dma_buf_export(void *priv, const struct dma_buf_ops *ops, 
	dmabuf->priv = priv;

	dmabuf->ops = ops;

	dmabuf->size = size;

	dmabuf->exp_name = exp_name;



	file = anon_inode_getfile("dmabuf", &dma_buf_fops, dmabuf, flags);
@@ -124,7 +127,7 @@ struct dma_buf *dma_buf_export(void *priv, const struct dma_buf_ops *ops, 


	return dmabuf;

}

EXPORT_SYMBOL_GPL(dma_buf_export);

EXPORT_SYMBOL_GPL(dma_buf_export_named);





/**

include/linux/dma-buf.h

+9 −2
Original line number Diff line number Diff line
@@ -112,6 +112,7 @@ struct dma_buf_ops { 
 * @file: file pointer used for sharing buffers across, and for refcounting.

 * @attachments: list of dma_buf_attachment that denotes all devices attached.

 * @ops: dma_buf_ops associated with this buffer object.

 * @exp_name: name of the exporter; useful for debugging.

 * @priv: exporter specific private data for this buffer object.

 */

struct dma_buf {
@@ -123,6 +124,7 @@ struct dma_buf { 
	struct mutex lock;

	unsigned vmapping_counter;

	void *vmap_ptr;

	const char *exp_name;

	void *priv;

};
@@ -162,8 +164,13 @@ struct dma_buf_attachment *dma_buf_attach(struct dma_buf *dmabuf, 
							struct device *dev);

void dma_buf_detach(struct dma_buf *dmabuf,

				struct dma_buf_attachment *dmabuf_attach);

struct dma_buf *dma_buf_export(void *priv, const struct dma_buf_ops *ops,

			       size_t size, int flags);



struct dma_buf *dma_buf_export_named(void *priv, const struct dma_buf_ops *ops,

			       size_t size, int flags, const char *);



#define dma_buf_export(priv, ops, size, flags)	\

	dma_buf_export_named(priv, ops, size, flags, __FILE__)



int dma_buf_fd(struct dma_buf *dmabuf, int flags);

struct dma_buf *dma_buf_get(int fd);

void dma_buf_put(struct dma_buf *dmabuf);