Commit a3860c1c authored by Xi Wang's avatar Xi Wang Committed by Linus Torvalds
Browse files

introduce SIZE_MAX 



ULONG_MAX is often used to check for integer overflow when calculating
allocation size.  While ULONG_MAX happens to work on most systems, there
is no guarantee that `size_t' must be the same size as `long'.

This patch introduces SIZE_MAX, the maximum value of `size_t', to improve
portability and readability for allocation size validation.

Signed-off-by: default avatarXi Wang <xi.wang@gmail.com>
Acked-by: default avatarAlex Elder <elder@dreamhost.com>
Cc: David Airlie <airlied@linux.ie>
Cc: Pekka Enberg <penberg@kernel.org>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 15837294

fs/ceph/snap.c

+1 −1
Original line number Diff line number Diff line
@@ -331,7 +331,7 @@ static int build_snap_context(struct ceph_snap_realm *realm) 


	/* alloc new snap context */

	err = -ENOMEM;

	if (num > (ULONG_MAX - sizeof(*snapc)) / sizeof(u64))

	if (num > (SIZE_MAX - sizeof(*snapc)) / sizeof(u64))

		goto fail;

	snapc = kzalloc(sizeof(*snapc) + num*sizeof(u64), GFP_NOFS);

	if (!snapc)

include/drm/drm_mem_util.h

+2 −2
Original line number Diff line number Diff line
@@ -31,7 +31,7 @@ 


static __inline__ void *drm_calloc_large(size_t nmemb, size_t size)

{

	if (size != 0 && nmemb > ULONG_MAX / size)

	if (size != 0 && nmemb > SIZE_MAX / size)

		return NULL;



	if (size * nmemb <= PAGE_SIZE)
@@ -44,7 +44,7 @@ static __inline__ void *drm_calloc_large(size_t nmemb, size_t size) 
/* Modeled after cairo's malloc_ab, it's like calloc but without the zeroing. */

static __inline__ void *drm_malloc_ab(size_t nmemb, size_t size)

{

	if (size != 0 && nmemb > ULONG_MAX / size)

	if (size != 0 && nmemb > SIZE_MAX / size)

		return NULL;



	if (size * nmemb <= PAGE_SIZE)

include/linux/kernel.h

+1 −0
Original line number Diff line number Diff line
@@ -35,6 +35,7 @@ 
#define LLONG_MAX	((long long)(~0ULL>>1))

#define LLONG_MIN	(-LLONG_MAX - 1)

#define ULLONG_MAX	(~0ULL)

#define SIZE_MAX	(~(size_t)0)



#define STACK_MAGIC	0xdeadbeef

include/linux/slab.h

+1 −1
Original line number Diff line number Diff line
@@ -242,7 +242,7 @@ size_t ksize(const void *); 
 */

static inline void *kmalloc_array(size_t n, size_t size, gfp_t flags)

{

	if (size != 0 && n > ULONG_MAX / size)

	if (size != 0 && n > SIZE_MAX / size)

		return NULL;

	return __kmalloc(n * size, flags);

}

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