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

Masahiro Yamada
2015-07-13T04:17:07Z

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)
--
1.9.1