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: Daniel Vetter daniel.vetter@ffwll.ch Signed-off-by: Sumit Semwal sumit.semwal@linaro.org --- Documentation/dma-buf-sharing.txt | 13 +++++++++++-- drivers/base/dma-buf.c | 11 +++++++---- include/linux/dma-buf.h | 11 +++++++++-- 3 files changed, 27 insertions(+), 8 deletions(-)
diff --git a/Documentation/dma-buf-sharing.txt b/Documentation/dma-buf-sharing.txt index 4966b1b..0b23261 100644 --- a/Documentation/dma-buf-sharing.txt +++ b/Documentation/dma-buf-sharing.txt @@ -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 diff --git a/drivers/base/dma-buf.c b/drivers/base/dma-buf.c index 2a7cb0d..d89102a 100644 --- a/drivers/base/dma-buf.c +++ b/drivers/base/dma-buf.c @@ -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);
/** diff --git a/include/linux/dma-buf.h b/include/linux/dma-buf.h index 9978b61..6f55c04 100644 --- a/include/linux/dma-buf.h +++ b/include/linux/dma-buf.h @@ -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);