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authorRasmus Villemoes <linux@rasmusvillemoes.dk>2015-04-16 02:17:05 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2015-04-16 02:35:23 +0300
commite26c12c777118d65aeb97eb1651338e7decae80e (patch)
tree55300d96e94c3e9efdaf434b8473ccc02536ba7d
parent51be17dfff753e72872f096ce1e654734f2fec50 (diff)
downloadlinux-e26c12c777118d65aeb97eb1651338e7decae80e.tar.xz
lib/vsprintf.c: reduce stack use in number()
At least since the initial git commit, when base was passed as a separate parameter, number() has only been called with bases 8, 10 and 16. I'm guessing that 66 was to accommodate 64 0/1, a sign and a '\0', but the buffer is only used for the actual digits. Octal digits carry 3 bits of information, so 24 is enough. Spell that 3*sizeof(num) so one less place needs to be changed should long long ever be 128 bits. Also remove the commented-out code that would handle an arbitrary base. Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Tejun Heo <tj@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--lib/vsprintf.c7
1 files changed, 1 insertions, 6 deletions
diff --git a/lib/vsprintf.c b/lib/vsprintf.c
index 318d583fe862..98f1ce907d3d 100644
--- a/lib/vsprintf.c
+++ b/lib/vsprintf.c
@@ -386,7 +386,7 @@ char *number(char *buf, char *end, unsigned long long num,
/* we are called with base 8, 10 or 16, only, thus don't need "G..." */
static const char digits[16] = "0123456789ABCDEF"; /* "GHIJKLMNOPQRSTUVWXYZ"; */
- char tmp[66];
+ char tmp[3 * sizeof(num)];
char sign;
char locase;
int need_pfx = ((spec.flags & SPECIAL) && spec.base != 10);
@@ -423,11 +423,6 @@ char *number(char *buf, char *end, unsigned long long num,
i = 0;
if (num < spec.base)
tmp[i++] = digits[num] | locase;
- /* Generic code, for any base:
- else do {
- tmp[i++] = (digits[do_div(num,base)] | locase);
- } while (num != 0);
- */
else if (spec.base != 10) { /* 8 or 16 */
int mask = spec.base - 1;
int shift = 3;