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authorAlexey Dobriyan <adobriyan@gmail.com>2006-10-01 02:27:20 -0400
committerLinus Torvalds <torvalds@g5.osdl.org>2006-10-01 03:39:19 -0400
commit1a2f67b459bb7846d4a15924face63eb2683acc2 (patch)
tree4c010d4c4220c9523342fb0daac90a433f36b53e /include/linux
parent9442e691e4aec85eba43ac60a3e77c77fd2e73a4 (diff)
[PATCH] kmemdup: introduce
One of idiomatic ways to duplicate a region of memory is dst = kmalloc(len, GFP_KERNEL); if (!dst) return -ENOMEM; memcpy(dst, src, len); which is neat code except a programmer needs to write size twice. Which sometimes leads to mistakes. If len passed to kmalloc is smaller that len passed to memcpy, it's straight overwrite-beyond-end. If len passed to memcpy is smaller than len passed to kmalloc, it's either a) legit behaviour ;-), or b) cloned buffer will contain garbage in second half. Slight trolling of commit lists shows several duplications bugs done exactly because of diverged lenghts: Linux: [CRYPTO]: Fix memcpy/memset args. [PATCH] memcpy/memset fixes OpenBSD: kerberosV/src/lib/asn1: der_copy.c:1.4 If programmer is given only one place to play with lengths, I believe, such mistakes could be avoided. With kmemdup, the snippet above will be rewritten as: dst = kmemdup(src, len, GFP_KERNEL); if (!dst) return -ENOMEM; This also leads to smaller code (kzalloc effect). Quick grep shows 200+ places where kmemdup() can be used. Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'include/linux')
-rw-r--r--include/linux/string.h1
1 files changed, 1 insertions, 0 deletions
diff --git a/include/linux/string.h b/include/linux/string.h
index e4c755860316..4f69ef9e6eb5 100644
--- a/include/linux/string.h
+++ b/include/linux/string.h
@@ -99,6 +99,7 @@ extern void * memchr(const void *,int,__kernel_size_t);
99#endif 99#endif
100 100
101extern char *kstrdup(const char *s, gfp_t gfp); 101extern char *kstrdup(const char *s, gfp_t gfp);
102extern void *kmemdup(const void *src, size_t len, gfp_t gfp);
102 103
103#ifdef __cplusplus 104#ifdef __cplusplus
104} 105}