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>

1 files changed, 1 insertions, 1 deletions

diff --git a/mm/util.c b/mm/util.c
index 18396ea63ee6..f2f21b775516 100644
--- a/mm/util.c
+++ b/mm/util.c
@@ -76,7 +76,7 @@ void *krealloc(const void *p, size_t new_size, gfp_t flags)
 
         if (unlikely(!new_size)) {
                 kfree(p);
-                return NULL;
+                return ZERO_SIZE_PTR;
         }
 
         ks = ksize(p);