[U-Boot] [PATCH v2 10/14] linux_compat: introduce GFP_DMA flag for kmalloc()

[Lukasz Majewski <l.majewski@samsung.com>]

Hi Masahiro,

> It does not seem efficient to always return cache-aligned memory.
> Return aligned memory only when GFP_DMA flag is given.
> 
> My main motivation for this commit is to refactor device_probe()
> and device_free() in the next commit.  DM_FLAG_ALLOC_PRIV_DMA
> should be handled more easily.
> 
> Signed-off-by: Masahiro Yamada <yamada.masahiro@socionext.com>
> ---
> 
> Changes in v2: None
> 
>  include/linux/compat.h | 1 +
>  lib/linux_compat.c     | 5 ++++-
>  2 files changed, 5 insertions(+), 1 deletion(-)
> 
> diff --git a/include/linux/compat.h b/include/linux/compat.h
> index fbebf91..13386c9 100644
> --- a/include/linux/compat.h
> +++ b/include/linux/compat.h
> @@ -41,6 +41,7 @@ extern struct p_current *current;
>  #define GFP_NOFS ((gfp_t) 0)
>  #define GFP_USER ((gfp_t) 0)
>  #define __GFP_NOWARN ((gfp_t) 0)
> +#define GFP_DMA		((__force gfp_t)0x01u)
>  #define __GFP_ZERO	((__force gfp_t)0x8000u)	/* Return
> zeroed page on success */ 
>  void *kmalloc(size_t size, int flags);
> diff --git a/lib/linux_compat.c b/lib/linux_compat.c
> index a936a7e..6da0cfa 100644
> --- a/lib/linux_compat.c
> +++ b/lib/linux_compat.c
> @@ -18,7 +18,10 @@ void *kmalloc(size_t size, int flags)
>  {
>  	void *p;
>  
> -	p = memalign(ARCH_DMA_MINALIGN, size);
> +	if (flags & GFP_DMA)
> +		p = memalign(ARCH_DMA_MINALIGN, size);
> +	else
> +		p = malloc(size);
>  	if (flags & __GFP_ZERO)
>  		memset(p, 0, size);
>  

Reviewed-by: Lukasz Majewski <l.majewski@samsung.com>

I hope that all places where kmalloc without GFP_DMA set is called
and implicitly require memalign'ed memory would be changed accordingly.

Otherwise we would have nasty, hard to find bugs.

-- 
Best regards,

Lukasz Majewski

Samsung R&D Institute Poland (SRPOL) | Linux Platform Group