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>

1 files changed, 12 insertions, 11 deletions

diff --git a/Documentation/dma-buf-sharing.txt b/Documentation/dma-buf-sharing.txt
index bb9753b635a3..480c8de3c2c4 100644
--- a/Documentation/dma-buf-sharing.txt
+++ b/Documentation/dma-buf-sharing.txt
@@ -49,25 +49,26 @@ The dma_buf buffer sharing API usage contains the following steps:
    The buffer exporter announces its wish to export a buffer. In this, it
    connects its own private buffer data, provides implementation for operations
    that can be performed on the exported dma_buf, and flags for the file
-   associated with this buffer.
+   associated with this buffer. All these fields are filled in struct
+   dma_buf_export_info, defined via the DEFINE_DMA_BUF_EXPORT_INFO macro.
 
    Interface:
-      struct dma_buf *dma_buf_export_named(void *priv, struct dma_buf_ops *ops,
-                                     size_t size, int flags,
-                                     const char *exp_name)
+      DEFINE_DMA_BUF_EXPORT_INFO(exp_info)
+      struct dma_buf *dma_buf_export(struct dma_buf_export_info *exp_info)
 
-   If this succeeds, dma_buf_export_named allocates a dma_buf structure, and
+   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.
+   'exp_name' in struct dma_buf_export_info is the name of exporter - to
+   facilitate information while debugging. It is set to KBUILD_MODNAME by
+   default, so exporters don't have to provide a specific name, if they don't
+   wish to.
+
+   DEFINE_DMA_BUF_EXPORT_INFO macro defines the struct dma_buf_export_info,
+   zeroes it out and pre-populates exp_name in it.
 
-   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 KBUILD_MODNAME pre-processor directive will be
-   inserted in place of 'exp_name' instead.
 
 2. Userspace gets a handle to pass around to potential buffer-users