Re: [REVIEW PATCH 1/2] videobuf2: add gfp_flags.

[Marek Szyprowski <m.szyprowski@samsung.com>]

Hello,

On 3/8/2013 10:21 AM, Hans Verkuil wrote:
> From: Hans Verkuil <hans.verkuil@cisco.com>
>
> 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>

> ---
>   drivers/media/v4l2-core/videobuf2-core.c       |    2 +-
>   drivers/media/v4l2-core/videobuf2-dma-contig.c |    5 +++--
>   drivers/media/v4l2-core/videobuf2-dma-sg.c     |    5 +++--
>   drivers/media/v4l2-core/videobuf2-vmalloc.c    |    4 ++--
>   include/media/videobuf2-core.h                 |   10 ++++++++--
>   5 files changed, 17 insertions(+), 9 deletions(-)
>
> diff --git a/drivers/media/v4l2-core/videobuf2-core.c b/drivers/media/v4l2-core/videobuf2-core.c
> index be04481..70827fe 100644
> --- a/drivers/media/v4l2-core/videobuf2-core.c
> +++ b/drivers/media/v4l2-core/videobuf2-core.c
> @@ -57,7 +57,7 @@ static int __vb2_buf_mem_alloc(struct vb2_buffer *vb)
>   	/* Allocate memory for all planes in this buffer */
>   	for (plane = 0; plane < vb->num_planes; ++plane) {
>   		mem_priv = call_memop(q, alloc, q->alloc_ctx[plane],
> -				      q->plane_sizes[plane]);
> +				      q->plane_sizes[plane], q->gfp_flags);
>   		if (IS_ERR_OR_NULL(mem_priv))
>   			goto free;
>   
> diff --git a/drivers/media/v4l2-core/videobuf2-dma-contig.c b/drivers/media/v4l2-core/videobuf2-dma-contig.c
> index 10beaee..ae35d25 100644
> --- a/drivers/media/v4l2-core/videobuf2-dma-contig.c
> +++ b/drivers/media/v4l2-core/videobuf2-dma-contig.c
> @@ -152,7 +152,7 @@ static void vb2_dc_put(void *buf_priv)
>   	kfree(buf);
>   }
>   
> -static void *vb2_dc_alloc(void *alloc_ctx, unsigned long size)
> +static void *vb2_dc_alloc(void *alloc_ctx, unsigned long size, gfp_t gfp_flags)
>   {
>   	struct vb2_dc_conf *conf = alloc_ctx;
>   	struct device *dev = conf->dev;
> @@ -165,7 +165,8 @@ static void *vb2_dc_alloc(void *alloc_ctx, unsigned long size)
>   	/* align image size to PAGE_SIZE */
>   	size = PAGE_ALIGN(size);
>   
> -	buf->vaddr = dma_alloc_coherent(dev, size, &buf->dma_addr, GFP_KERNEL);
> +	buf->vaddr = dma_alloc_coherent(dev, size, &buf->dma_addr,
> +						GFP_KERNEL | gfp_flags);
>   	if (!buf->vaddr) {
>   		dev_err(dev, "dma_alloc_coherent of size %ld failed\n", size);
>   		kfree(buf);
> diff --git a/drivers/media/v4l2-core/videobuf2-dma-sg.c b/drivers/media/v4l2-core/videobuf2-dma-sg.c
> index 25c3b36..952776f 100644
> --- a/drivers/media/v4l2-core/videobuf2-dma-sg.c
> +++ b/drivers/media/v4l2-core/videobuf2-dma-sg.c
> @@ -33,7 +33,7 @@ struct vb2_dma_sg_buf {
>   
>   static void vb2_dma_sg_put(void *buf_priv);
>   
> -static void *vb2_dma_sg_alloc(void *alloc_ctx, unsigned long size)
> +static void *vb2_dma_sg_alloc(void *alloc_ctx, unsigned long size, gfp_t gfp_flags)
>   {
>   	struct vb2_dma_sg_buf *buf;
>   	int i;
> @@ -60,7 +60,8 @@ static void *vb2_dma_sg_alloc(void *alloc_ctx, unsigned long size)
>   		goto fail_pages_array_alloc;
>   
>   	for (i = 0; i < buf->sg_desc.num_pages; ++i) {
> -		buf->pages[i] = alloc_page(GFP_KERNEL | __GFP_ZERO | __GFP_NOWARN);
> +		buf->pages[i] = alloc_page(GFP_KERNEL | __GFP_ZERO |
> +					   __GFP_NOWARN | gfp_flags);
>   		if (NULL == buf->pages[i])
>   			goto fail_pages_alloc;
>   		sg_set_page(&buf->sg_desc.sglist[i],
> diff --git a/drivers/media/v4l2-core/videobuf2-vmalloc.c b/drivers/media/v4l2-core/videobuf2-vmalloc.c
> index a47fd4f..313d977 100644
> --- a/drivers/media/v4l2-core/videobuf2-vmalloc.c
> +++ b/drivers/media/v4l2-core/videobuf2-vmalloc.c
> @@ -35,11 +35,11 @@ struct vb2_vmalloc_buf {
>   
>   static void vb2_vmalloc_put(void *buf_priv);
>   
> -static void *vb2_vmalloc_alloc(void *alloc_ctx, unsigned long size)
> +static void *vb2_vmalloc_alloc(void *alloc_ctx, unsigned long size, gfp_t gfp_flags)
>   {
>   	struct vb2_vmalloc_buf *buf;
>   
> -	buf = kzalloc(sizeof(*buf), GFP_KERNEL);
> +	buf = kzalloc(sizeof(*buf), GFP_KERNEL | gfp_flags);
>   	if (!buf)
>   		return NULL;
>   
> 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;

Best regards
-- 
Marek Szyprowski
Samsung Poland R&D Center