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author | Christoph Lameter <clameter@sgi.com> | 2007-07-17 04:03:22 -0700 |
---|---|---|
committer | Linus Torvalds <torvalds@woody.linux-foundation.org> | 2007-07-17 10:23:01 -0700 |
commit | 6cb8f91320d3e720351c21741da795fed580b21b (patch) | |
tree | c9f73c8b82cd0f6c534939b8b9f36e8615b0ab2d /include | |
parent | ef2ad80c7d255ed0449eda947c2d700635b7e0f5 (diff) | |
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Slab allocators: consistent ZERO_SIZE_PTR support and NULL result semantics
Define ZERO_OR_NULL_PTR macro to be able to remove the checks from the
allocators. Move ZERO_SIZE_PTR related stuff into slab.h.
Make ZERO_SIZE_PTR work for all slab allocators and get rid of the
WARN_ON_ONCE(size == 0) that is still remaining in SLAB.
Make slub return NULL like the other allocators if a too large memory segment
is requested via __kmalloc.
Signed-off-by: Christoph Lameter <clameter@sgi.com>
Acked-by: Pekka Enberg <penberg@cs.helsinki.fi>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'include')
-rw-r--r-- | include/linux/slab.h | 13 | ||||
-rw-r--r-- | include/linux/slab_def.h | 12 | ||||
-rw-r--r-- | include/linux/slub_def.h | 12 |
3 files changed, 25 insertions, 12 deletions
diff --git a/include/linux/slab.h b/include/linux/slab.h index 27402fe..0289ec8 100644 --- a/include/linux/slab.h +++ b/include/linux/slab.h @@ -31,6 +31,19 @@ #define SLAB_TRACE 0x00200000UL /* Trace allocations and frees */ /* + * ZERO_SIZE_PTR will be returned for zero sized kmalloc requests. + * + * Dereferencing ZERO_SIZE_PTR will lead to a distinct access fault. + * + * ZERO_SIZE_PTR can be passed to kfree though in the same way that NULL can. + * Both make kfree a no-op. + */ +#define ZERO_SIZE_PTR ((void *)16) + +#define ZERO_OR_NULL_PTR(x) ((unsigned long)(x) < \ + (unsigned long)ZERO_SIZE_PTR) + +/* * struct kmem_cache related prototypes */ void __init kmem_cache_init(void); diff --git a/include/linux/slab_def.h b/include/linux/slab_def.h index 365d036..16e814f 100644 --- a/include/linux/slab_def.h +++ b/include/linux/slab_def.h @@ -32,6 +32,10 @@ static inline void *kmalloc(size_t size, gfp_t flags) { if (__builtin_constant_p(size)) { int i = 0; + + if (!size) + return ZERO_SIZE_PTR; + #define CACHE(x) \ if (size <= x) \ goto found; \ @@ -58,6 +62,10 @@ static inline void *kzalloc(size_t size, gfp_t flags) { if (__builtin_constant_p(size)) { int i = 0; + + if (!size) + return ZERO_SIZE_PTR; + #define CACHE(x) \ if (size <= x) \ goto found; \ @@ -88,6 +96,10 @@ static inline void *kmalloc_node(size_t size, gfp_t flags, int node) { if (__builtin_constant_p(size)) { int i = 0; + + if (!size) + return ZERO_SIZE_PTR; + #define CACHE(x) \ if (size <= x) \ goto found; \ diff --git a/include/linux/slub_def.h b/include/linux/slub_def.h index a582f67..579b0a2 100644 --- a/include/linux/slub_def.h +++ b/include/linux/slub_def.h @@ -159,18 +159,6 @@ static inline struct kmem_cache *kmalloc_slab(size_t size) #define SLUB_DMA 0 #endif - -/* - * ZERO_SIZE_PTR will be returned for zero sized kmalloc requests. - * - * Dereferencing ZERO_SIZE_PTR will lead to a distinct access fault. - * - * ZERO_SIZE_PTR can be passed to kfree though in the same way that NULL can. - * Both make kfree a no-op. - */ -#define ZERO_SIZE_PTR ((void *)16) - - void *kmem_cache_alloc(struct kmem_cache *, gfp_t); void *__kmalloc(size_t size, gfp_t flags); |