[U-Boot] [PATCH v2 04/14] linux_compat: handle __GFP_ZERO in kmalloc()

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

Hi Masahiro,

> 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@socionext.com>
> Reviewed-by: Heiko Schocher <hs@denx.de>
> Acked-by: Simon Glass <sjg@chromium.org>
> ---
> 
> Changes in v2: None
> 
>  include/linux/compat.h | 20 ++++++++++++--------
>  lib/linux_compat.c     | 13 ++++++-------
>  2 files changed, 18 insertions(+), 15 deletions(-)
> 
> diff --git a/include/linux/compat.h b/include/linux/compat.h
> index a3d136b..fbebf91 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)

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

-- 
Best regards,

Lukasz Majewski

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