diff options
Diffstat (limited to 'include/linux/slub_def.h')
| -rw-r--r-- | include/linux/slub_def.h | 38 |
1 files changed, 28 insertions, 10 deletions
diff --git a/include/linux/slub_def.h b/include/linux/slub_def.h index 0764c829d96..6207a3d8da7 100644 --- a/include/linux/slub_def.h +++ b/include/linux/slub_def.h @@ -28,7 +28,7 @@ struct kmem_cache { int size; /* The size of an object including meta data */ int objsize; /* The size of an object without meta data */ int offset; /* Free pointer offset. */ - unsigned int order; + int order; /* * Avoid an extra cache line for UP, SMP and for the node local to @@ -56,7 +56,13 @@ struct kmem_cache { /* * Kmalloc subsystem. */ -#define KMALLOC_SHIFT_LOW 3 +#if defined(ARCH_KMALLOC_MINALIGN) && ARCH_KMALLOC_MINALIGN > 8 +#define KMALLOC_MIN_SIZE ARCH_KMALLOC_MINALIGN +#else +#define KMALLOC_MIN_SIZE 8 +#endif + +#define KMALLOC_SHIFT_LOW ilog2(KMALLOC_MIN_SIZE) /* * We keep the general caches in an array of slab caches that are used for @@ -70,15 +76,15 @@ extern struct kmem_cache kmalloc_caches[KMALLOC_SHIFT_HIGH + 1]; */ static inline int kmalloc_index(size_t size) { - /* - * We should return 0 if size == 0 but we use the smallest object - * here for SLAB legacy reasons. - */ - WARN_ON_ONCE(size == 0); + if (!size) + return 0; if (size > KMALLOC_MAX_SIZE) return -1; + if (size <= KMALLOC_MIN_SIZE) + return KMALLOC_SHIFT_LOW; + if (size > 64 && size <= 96) return 1; if (size > 128 && size <= 192) @@ -153,13 +159,25 @@ 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) + + static inline void *kmalloc(size_t size, gfp_t flags) { if (__builtin_constant_p(size) && !(flags & SLUB_DMA)) { struct kmem_cache *s = kmalloc_slab(size); if (!s) - return NULL; + return ZERO_SIZE_PTR; return kmem_cache_alloc(s, flags); } else @@ -172,7 +190,7 @@ static inline void *kzalloc(size_t size, gfp_t flags) struct kmem_cache *s = kmalloc_slab(size); if (!s) - return NULL; + return ZERO_SIZE_PTR; return kmem_cache_zalloc(s, flags); } else @@ -188,7 +206,7 @@ static inline void *kmalloc_node(size_t size, gfp_t flags, int node) struct kmem_cache *s = kmalloc_slab(size); if (!s) - return NULL; + return ZERO_SIZE_PTR; return kmem_cache_alloc_node(s, flags, node); } else |