[PATCH] cpumask: fix double string traverse in cpumask_parse

From: Yury Norov
Date: Tue Apr 09 2019 - 16:42:17 EST


From: Yury Norov <ynorov@xxxxxxxxxxx>

cpumask_parse() finds first occurrence of either \n or \0 by calling
strchr() and strlen(). We can do it better with a single call of
strchrnul().

Signed-off-by: Yury Norov <ynorov@xxxxxxxxxxx>
---
include/linux/cpumask.h | 3 +--
1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/include/linux/cpumask.h b/include/linux/cpumask.h
index 147bdec42215..2b87f35c586c 100644
--- a/include/linux/cpumask.h
+++ b/include/linux/cpumask.h
@@ -633,8 +633,7 @@ static inline int cpumask_parselist_user(const char __user *buf, int len,
*/
static inline int cpumask_parse(const char *buf, struct cpumask *dstp)
{
- char *nl = strchr(buf, '\n');
- unsigned int len = nl ? (unsigned int)(nl - buf) : strlen(buf);
+ unsigned int len = (unsigned int)(strchrnul(buf, '\n') - buf);

return bitmap_parse(buf, len, cpumask_bits(dstp), nr_cpumask_bits);
}
--
2.17.1