[media] videobuf2: add gfp_flags

Some drivers have special memory requirements for their buffers, usually
related to DMA (e.g. GFP_DMA or __GFP_DMA32). Make it possible to specify
additional GFP flags for those buffers by adding a gfp_flags field to
vb2_queue.
Note that this field will be replaced in the future with a different
mechanism, but that is still work in progress and we need this feature
now so we won't be able to convert drivers with such requirements to vb2.

Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Acked-by: Marek Szyprowski <m.szyprowski@samsung.com>
Acked-by: Federico Vaga <federico.vaga@gmail.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>

1 files changed, 8 insertions, 2 deletions

diff --git a/include/media/videobuf2-core.h b/include/media/videobuf2-core.h
index a2d4274..d88a098 100644
--- a/include/media/videobuf2-core.h
+++ b/include/media/videobuf2-core.h
@@ -27,7 +27,9 @@ struct vb2_fileio_data;
  *		return NULL on failure or a pointer to allocator private,
  *		per-buffer data on success; the returned private structure
  *		will then be passed as buf_priv argument to other ops in this
- *		structure
+ *		structure. Additional gfp_flags to use when allocating the
+ *		are also passed to this operation. These flags are from the
+ *		gfp_flags field of vb2_queue.
  * @put:	inform the allocator that the buffer will no longer be used;
  *		usually will result in the allocator freeing the buffer (if
  *		no other users of this buffer are present); the buf_priv
@@ -79,7 +81,7 @@ struct vb2_fileio_data;
  *				  unmap_dmabuf.
  */
 struct vb2_mem_ops {
-	void		*(*alloc)(void *alloc_ctx, unsigned long size);
+	void		*(*alloc)(void *alloc_ctx, unsigned long size, gfp_t gfp_flags);
 	void		(*put)(void *buf_priv);
 	struct dma_buf *(*get_dmabuf)(void *buf_priv);
 
@@ -302,6 +304,9 @@ struct v4l2_fh;
  * @buf_struct_size: size of the driver-specific buffer structure;
  *		"0" indicates the driver doesn't want to use a custom buffer
  *		structure type, so sizeof(struct vb2_buffer) will is used
+ * @gfp_flags:	additional gfp flags used when allocating the buffers.
+ *		Typically this is 0, but it may be e.g. GFP_DMA or __GFP_DMA32
+ *		to force the buffer allocation to a specific memory zone.
  *
  * @memory:	current memory type used
  * @bufs:	videobuf buffer structures
@@ -327,6 +332,7 @@ struct vb2_queue {
 	void				*drv_priv;
 	unsigned int			buf_struct_size;
 	u32				timestamp_type;
+	gfp_t				gfp_flags;
 
 /* private: internal use only */
 	enum v4l2_memory		memory;