RE: [PATCH] videobuf2: Do not unconditionally map S/G buffers into kernel space

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



Hello,

On Thursday, July 14, 2011 11:11 PM Jonathan Corbet wrote:

> The one in-tree videobuf2-dma-sg driver (mmp-camera) has no need for a
> kernel-space mapping of the buffers; one suspects that most other drivers
> would not either.  The videobuf2-dma-sg module does the right thing if
> buf->vaddr == NULL - it maps the buffer on demand if somebody needs it.  So
> let's not map the buffer at allocation time; that will save a little CPU
> time and a lot of address space in the vmalloc range.
> 
> Signed-off-by: Jonathan Corbet <corbet@xxxxxxx>

Acked-by: Marek Szyprowski <m.szyprowski@xxxxxxxxxxx>

> ---
>  drivers/media/video/videobuf2-dma-sg.c |    6 ------
>  1 files changed, 0 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/media/video/videobuf2-dma-sg.c
> b/drivers/media/video/videobuf2-dma-sg.c
> index b2d9485..0e8edc1 100644
> --- a/drivers/media/video/videobuf2-dma-sg.c
> +++ b/drivers/media/video/videobuf2-dma-sg.c
> @@ -77,12 +77,6 @@ static void *vb2_dma_sg_alloc(void *alloc_ctx, unsigned
> long size)
> 
>  	printk(KERN_DEBUG "%s: Allocated buffer of %d pages\n",
>  		__func__, buf->sg_desc.num_pages);
> -
> -	if (!buf->vaddr)
> -		buf->vaddr = vm_map_ram(buf->pages,
> -					buf->sg_desc.num_pages,
> -					-1,
> -					PAGE_KERNEL);
>  	return buf;
> 
>  fail_pages_alloc:
> --
> 1.7.6

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


--
To unsubscribe from this list: send the line "unsubscribe linux-media" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html


[Index of Archives]     [Linux Input]     [Video for Linux]     [Gstreamer Embedded]     [Mplayer Users]     [Linux USB Devel]     [Linux Audio Users]     [Linux Kernel]     [Linux SCSI]     [Yosemite Backpacking]
  Powered by Linux