linux_dsm_epyc7002/fs/proc/util.c
Alexey Dobriyan 0746a0bc6e proc: use do-while in name_to_int()
Gcc doesn't know that "len" is guaranteed to be >=1 by dcache and
generates standard while-loop prologue duplicating loop condition.

	add/remove: 0/0 grow/shrink: 0/1 up/down: 0/-27 (-27)
	function                                     old     new   delta
	name_to_int                                  104      77     -27

Link: http://lkml.kernel.org/r/20170912195213.GB17730@avx2
Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-11-17 16:10:00 -08:00

24 lines
361 B
C

#include <linux/dcache.h>
unsigned name_to_int(const struct qstr *qstr)
{
const char *name = qstr->name;
int len = qstr->len;
unsigned n = 0;
if (len > 1 && *name == '0')
goto out;
do {
unsigned c = *name++ - '0';
if (c > 9)
goto out;
if (n >= (~0U-9)/10)
goto out;
n *= 10;
n += c;
} while (--len > 0);
return n;
out:
return ~0U;
}