Merge master.kernel.org:/pub/scm/linux/kernel/git/gregkh/usb-2.6

[mv-sheeva.git] / mm / slub.c

diff --git a/mm/slub.c b/mm/slub.c
index 51663a3c3c243c1afeaba27e21b7333808bc1cff..c9ab68881b43ebe8525fb2fa1e943f9810229c21 100644 (file)
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -2241,7 +2241,7 @@ void *__kmalloc(size_t size, gfp_t flags)
 
        if (s)
                return slab_alloc(s, flags, -1, __builtin_return_address(0));
-       return NULL;
+       return ZERO_SIZE_PTR;
 }
 EXPORT_SYMBOL(__kmalloc);
 
@@ -2252,16 +2252,20 @@ void *__kmalloc_node(size_t size, gfp_t flags, int node)
 
        if (s)
                return slab_alloc(s, flags, node, __builtin_return_address(0));
-       return NULL;
+       return ZERO_SIZE_PTR;
 }
 EXPORT_SYMBOL(__kmalloc_node);
 #endif
 
 size_t ksize(const void *object)
 {
-       struct page *page = get_object_page(object);
+       struct page *page;
        struct kmem_cache *s;
 
+       if (object == ZERO_SIZE_PTR)
+               return 0;
+
+       page = get_object_page(object);
        BUG_ON(!page);
        s = page->slab;
        BUG_ON(!s);
@@ -2293,7 +2297,13 @@ void kfree(const void *x)
        struct kmem_cache *s;
        struct page *page;
 
-       if (!x)
+       /*
+        * This has to be an unsigned comparison. According to Linus
+        * some gcc version treat a pointer as a signed entity. Then
+        * this comparison would be true for all "negative" pointers
+        * (which would cover the whole upper half of the address space).
+        */
+       if ((unsigned long)x <= (unsigned long)ZERO_SIZE_PTR)
                return;
 
        page = virt_to_head_page(x);
@@ -2398,12 +2408,12 @@ void *krealloc(const void *p, size_t new_size, gfp_t flags)
        void *ret;
        size_t ks;
 
-       if (unlikely(!p))
+       if (unlikely(!p || p == ZERO_SIZE_PTR))
                return kmalloc(new_size, flags);
 
        if (unlikely(!new_size)) {
                kfree(p);
-               return NULL;
+               return ZERO_SIZE_PTR;
        }
 
        ks = ksize(p);
@@ -2652,7 +2662,7 @@ void *__kmalloc_track_caller(size_t size, gfp_t gfpflags, void *caller)
        struct kmem_cache *s = get_slab(size, gfpflags);
 
        if (!s)
-               return NULL;
+               return ZERO_SIZE_PTR;
 
        return slab_alloc(s, gfpflags, -1, caller);
 }
@@ -2663,7 +2673,7 @@ void *__kmalloc_node_track_caller(size_t size, gfp_t gfpflags,
        struct kmem_cache *s = get_slab(size, gfpflags);
 
        if (!s)
-               return NULL;
+               return ZERO_SIZE_PTR;
 
        return slab_alloc(s, gfpflags, node, caller);
 }