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-rw-r--r--include/linux/slab.h13
-rw-r--r--include/linux/slab_def.h12
-rw-r--r--include/linux/slub_def.h12
-rw-r--r--mm/slab.c13
-rw-r--r--mm/slob.c11
-rw-r--r--mm/slub.c29
-rw-r--r--mm/util.c2
7 files changed, 57 insertions, 35 deletions
diff --git a/include/linux/slab.h b/include/linux/slab.h
index 27402fea9b7..0289ec89300 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 365d036c454..16e814ffab8 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 a582f677152..579b0a22858 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);
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));
diff --git a/mm/slob.c b/mm/slob.c
index 154e7bdf354..41d32c3c0be 100644
--- a/mm/slob.c
+++ b/mm/slob.c
@@ -347,7 +347,7 @@ static void slob_free(void *block, int size)
slobidx_t units;
unsigned long flags;
- if (!block)
+ if (ZERO_OR_NULL_PTR(block))
return;
BUG_ON(!size);
@@ -424,10 +424,13 @@ out:
void *__kmalloc_node(size_t size, gfp_t gfp, int node)
{
+ unsigned int *m;
int align = max(ARCH_KMALLOC_MINALIGN, ARCH_SLAB_MINALIGN);
if (size < PAGE_SIZE - align) {
- unsigned int *m;
+ if (!size)
+ return ZERO_SIZE_PTR;
+
m = slob_alloc(size + align, gfp, align, node);
if (m)
*m = size;
@@ -450,7 +453,7 @@ void kfree(const void *block)
{
struct slob_page *sp;
- if (!block)
+ if (ZERO_OR_NULL_PTR(block))
return;
sp = (struct slob_page *)virt_to_page(block);
@@ -468,7 +471,7 @@ size_t ksize(const void *block)
{
struct slob_page *sp;
- if (!block)
+ if (ZERO_OR_NULL_PTR(block))
return 0;
sp = (struct slob_page *)virt_to_page(block);
diff --git a/mm/slub.c b/mm/slub.c
index 1b0a95d75db..548d78df81e 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -2270,10 +2270,11 @@ static struct kmem_cache *get_slab(size_t size, gfp_t flags)
int index = kmalloc_index(size);
if (!index)
- return NULL;
+ return ZERO_SIZE_PTR;
/* Allocation too large? */
- BUG_ON(index < 0);
+ if (index < 0)
+ return NULL;
#ifdef CONFIG_ZONE_DMA
if ((flags & SLUB_DMA)) {
@@ -2314,9 +2315,10 @@ void *__kmalloc(size_t size, gfp_t flags)
{
struct kmem_cache *s = get_slab(size, flags);
- if (s)
- return slab_alloc(s, flags, -1, __builtin_return_address(0));
- return ZERO_SIZE_PTR;
+ if (ZERO_OR_NULL_PTR(s))
+ return s;
+
+ return slab_alloc(s, flags, -1, __builtin_return_address(0));
}
EXPORT_SYMBOL(__kmalloc);
@@ -2325,9 +2327,10 @@ void *__kmalloc_node(size_t size, gfp_t flags, int node)
{
struct kmem_cache *s = get_slab(size, flags);
- if (s)
- return slab_alloc(s, flags, node, __builtin_return_address(0));
- return ZERO_SIZE_PTR;
+ if (ZERO_OR_NULL_PTR(s))
+ return s;
+
+ return slab_alloc(s, flags, node, __builtin_return_address(0));
}
EXPORT_SYMBOL(__kmalloc_node);
#endif
@@ -2378,7 +2381,7 @@ void kfree(const void *x)
* 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)
+ if (ZERO_OR_NULL_PTR(x))
return;
page = virt_to_head_page(x);
@@ -2687,8 +2690,8 @@ void *__kmalloc_track_caller(size_t size, gfp_t gfpflags, void *caller)
{
struct kmem_cache *s = get_slab(size, gfpflags);
- if (!s)
- return ZERO_SIZE_PTR;
+ if (ZERO_OR_NULL_PTR(s))
+ return s;
return slab_alloc(s, gfpflags, -1, caller);
}
@@ -2698,8 +2701,8 @@ void *__kmalloc_node_track_caller(size_t size, gfp_t gfpflags,
{
struct kmem_cache *s = get_slab(size, gfpflags);
- if (!s)
- return ZERO_SIZE_PTR;
+ if (ZERO_OR_NULL_PTR(s))
+ return s;
return slab_alloc(s, gfpflags, node, caller);
}
diff --git a/mm/util.c b/mm/util.c
index 18396ea63ee..f2f21b77551 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);
generated by cgit v1.2.3-18-g5258 (git 2.32.0) at 2024-12-01 07:41:18 +0000