[U-Boot] [RFC PATCH 04/12] linux_compat: handle __GFP_ZERO in kmalloc()

[Heiko Schocher]

Hello Masahiro,

Am 08.07.2015 um 06:29 schrieb Masahiro Yamada:
> Currently, kzalloc() returns zero-filled memory, while kmalloc()
> simply ignores the second argument and never fills the memory
> area with zeros.
>
> I want kmalloc(size, __GFP_ZERO) to behave as kzalloc() does,
> which will make it easier to add more memory allocator variants.
>
> With the introduction of __GFP_ZERO flag, going forward, kzmalloc()
> variants can fall back to kmalloc() enabling the __GFP_ZERO flag.
>
> Signed-off-by: Masahiro Yamada <yamada.masahiro at socionext.com>
> ---
>
>   include/linux/compat.h | 20 ++++++++++++--------
>   lib/linux_compat.c     | 13 ++++++-------
>   2 files changed, 18 insertions(+), 15 deletions(-)

Reviewed-by: Heiko Schocher <hs at denx.de>

bye,
Heiko
>
> diff --git a/include/linux/compat.h b/include/linux/compat.h
> index a3d136b..64988bf 100644
> --- a/include/linux/compat.h
> +++ b/include/linux/compat.h
> @@ -36,8 +36,19 @@ extern struct p_current *current;
>   #define KERN_INFO
>   #define KERN_DEBUG
>
> +#define GFP_ATOMIC ((gfp_t) 0)
> +#define GFP_KERNEL ((gfp_t) 0)
> +#define GFP_NOFS ((gfp_t) 0)
> +#define GFP_USER ((gfp_t) 0)
> +#define __GFP_NOWARN ((gfp_t) 0)
> +#define __GFP_ZERO	((__force gfp_t)0x8000u) /* Return zeroed page on success */
> +
>   void *kmalloc(size_t size, int flags);
> -void *kzalloc(size_t size, int flags);
> +
> +static inline void *kzalloc(size_t size, gfp_t flags)
> +{
> +	return kmalloc(size, flags | __GFP_ZERO);
> +}
>   #define vmalloc(size)	kmalloc(size, 0)
>   #define __vmalloc(size, flags, pgsz)	kmalloc(size, flags)
>   static inline void *vzalloc(unsigned long size)
> @@ -77,13 +88,6 @@ void *kmem_cache_alloc(struct kmem_cache *obj, int flag);
>   /* drivers/char/random.c */
>   #define get_random_bytes(...)
>
> -/* idr.c */
> -#define GFP_ATOMIC ((gfp_t) 0)
> -#define GFP_KERNEL ((gfp_t) 0)
> -#define GFP_NOFS ((gfp_t) 0)
> -#define GFP_USER ((gfp_t) 0)
> -#define __GFP_NOWARN ((gfp_t) 0)
> -
>   /* include/linux/leds.h */
>   struct led_trigger {};
>
> diff --git a/lib/linux_compat.c b/lib/linux_compat.c
> index 8c7a7b5..a936a7e 100644
> --- a/lib/linux_compat.c
> +++ b/lib/linux_compat.c
> @@ -16,14 +16,13 @@ unsigned long copy_from_user(void *dest, const void *src,
>
>   void *kmalloc(size_t size, int flags)
>   {
> -	return memalign(ARCH_DMA_MINALIGN, size);
> -}
> +	void *p;
>
> -void *kzalloc(size_t size, int flags)
> -{
> -	void *ptr = kmalloc(size, flags);
> -	memset(ptr, 0, size);
> -	return ptr;
> +	p = memalign(ARCH_DMA_MINALIGN, size);
> +	if (flags & __GFP_ZERO)
> +		memset(p, 0, size);
> +
> +	return p;
>   }
>
>   struct kmem_cache *get_mem(int element_sz)
>

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