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

Lukasz Majewski
2015-07-13T07:47:31Z

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