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| author | Xi Wang <xi.wang@gmail.com> | 2012-05-31 16:26:04 -0700 |
|---|---|---|
| committer | Ben Hutchings <ben@decadent.org.uk> | 2014-08-06 18:07:42 +0100 |
| commit | b11597b7041b76aa25855db6028fad853201c54e (patch) | |
| tree | 42faf8759af6b96f5c67a17691ecd3d50223ec58 | |
| parent | ce4ded58d4b5869153cf5fde839161dff974cf94 (diff) | |
| download | lwn-b11597b7041b76aa25855db6028fad853201c54e.tar.gz lwn-b11597b7041b76aa25855db6028fad853201c54e.zip | |
introduce SIZE_MAX
commit a3860c1c5dd1137db23d7786d284939c5761d517 upstream.
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: Xi Wang <xi.wang@gmail.com>
Acked-by: Alex Elder <elder@dreamhost.com>
Cc: David Airlie <airlied@linux.ie>
Cc: Pekka Enberg <penberg@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
| -rw-r--r-- | fs/ceph/snap.c | 2 | ||||
| -rw-r--r-- | include/drm/drm_mem_util.h | 4 | ||||
| -rw-r--r-- | include/linux/kernel.h | 1 | ||||
| -rw-r--r-- | include/linux/slab.h | 2 |
4 files changed, 5 insertions, 4 deletions
diff --git a/fs/ceph/snap.c b/fs/ceph/snap.c index f04c0961f993..e5206fc76562 100644 --- a/fs/ceph/snap.c +++ b/fs/ceph/snap.c @@ -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) diff --git a/include/drm/drm_mem_util.h b/include/drm/drm_mem_util.h index 6bd325fedc87..19a240446fca 100644 --- a/include/drm/drm_mem_util.h +++ b/include/drm/drm_mem_util.h @@ -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) diff --git a/include/linux/kernel.h b/include/linux/kernel.h index a70783d199e4..0b8ca35595c9 100644 --- a/include/linux/kernel.h +++ b/include/linux/kernel.h @@ -34,6 +34,7 @@ #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 diff --git a/include/linux/slab.h b/include/linux/slab.h index a595dce6b0c7..67d5d94b783a 100644 --- a/include/linux/slab.h +++ b/include/linux/slab.h @@ -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); } |