From 6cb8f91320d3e720351c21741da795fed580b21b Mon Sep 17 00:00:00 2001 From: Christoph Lameter Date: Tue, 17 Jul 2007 04:03:22 -0700 Subject: 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 Acked-by: Pekka Enberg Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/slab.c | 13 ++++++++----- 1 file changed, 8 insertions(+), 5 deletions(-) (limited to 'mm/slab.c') diff --git a/mm/slab.c b/mm/slab.c index 4bd8a53091b..d2cd304fd8a 100644 --- a/mm/slab.c +++ b/mm/slab.c @@ -775,6 +775,9 @@ static inline struct kmem_cache *__find_general_cachep(size_t size, */ BUG_ON(malloc_sizes[INDEX_AC].cs_cachep == NULL); #endif + if (!size) + return ZERO_SIZE_PTR; + while (size > csizep->cs_size) csizep++; @@ -2351,7 +2354,7 @@ kmem_cache_create (const char *name, size_t size, size_t align, * this should not happen at all. * But leave a BUG_ON for some lucky dude. */ - BUG_ON(!cachep->slabp_cache); + BUG_ON(ZERO_OR_NULL_PTR(cachep->slabp_cache)); } cachep->ctor = ctor; cachep->name = name; @@ -3653,8 +3656,8 @@ __do_kmalloc_node(size_t size, gfp_t flags, int node, void *caller) struct kmem_cache *cachep; cachep = kmem_find_general_cachep(size, flags); - if (unlikely(cachep == NULL)) - return NULL; + if (unlikely(ZERO_OR_NULL_PTR(cachep))) + return cachep; return kmem_cache_alloc_node(cachep, flags, node); } @@ -3760,7 +3763,7 @@ void kfree(const void *objp) struct kmem_cache *c; unsigned long flags; - if (unlikely(!objp)) + if (unlikely(ZERO_OR_NULL_PTR(objp))) return; local_irq_save(flags); kfree_debugcheck(objp); @@ -4447,7 +4450,7 @@ const struct seq_operations slabstats_op = { */ size_t ksize(const void *objp) { - if (unlikely(objp == NULL)) + if (unlikely(ZERO_OR_NULL_PTR(objp))) return 0; return obj_size(virt_to_cache(objp)); -- cgit v1.2.3