2019-08-02 02:32:35

by Chuhong Yuan

[permalink] [raw]
Subject: [PATCH v2 08/10] sched: Replace strncmp with str_has_prefix

strncmp(str, const, len) is error-prone because len
is easy to have typo.
The example is the hard-coded len has counting error
or sizeof(const) forgets - 1.
So we prefer using newly introduced str_has_prefix
to substitute such strncmp.

Signed-off-by: Chuhong Yuan <[email protected]>
---
Changes in v2:
- Revise the description.
- Utilize str_has_prefix's return value to
eliminate some hard codes.

kernel/sched/debug.c | 5 +++--
kernel/sched/isolation.c | 9 +++++----
2 files changed, 8 insertions(+), 6 deletions(-)

diff --git a/kernel/sched/debug.c b/kernel/sched/debug.c
index f7e4579e746c..43983ff325b7 100644
--- a/kernel/sched/debug.c
+++ b/kernel/sched/debug.c
@@ -102,10 +102,11 @@ static int sched_feat_set(char *cmp)
{
int i;
int neg = 0;
+ size_t len;

- if (strncmp(cmp, "NO_", 3) == 0) {
+ if ((len = str_has_prefix(cmp, "NO_"))) {
neg = 1;
- cmp += 3;
+ cmp += len;
}

i = match_string(sched_feat_names, __SCHED_FEAT_NR, cmp);
diff --git a/kernel/sched/isolation.c b/kernel/sched/isolation.c
index ccb28085b114..f528bb5996f4 100644
--- a/kernel/sched/isolation.c
+++ b/kernel/sched/isolation.c
@@ -141,16 +141,17 @@ __setup("nohz_full=", housekeeping_nohz_full_setup);
static int __init housekeeping_isolcpus_setup(char *str)
{
unsigned int flags = 0;
+ size_t len;

while (isalpha(*str)) {
- if (!strncmp(str, "nohz,", 5)) {
- str += 5;
+ if ((len = str_has_prefix(str, "nohz,"))) {
+ str += len;
flags |= HK_FLAG_TICK;
continue;
}

- if (!strncmp(str, "domain,", 7)) {
- str += 7;
+ if ((len = str_has_prefix(str, "domain,"))) {
+ str += len;
flags |= HK_FLAG_DOMAIN;
continue;
}
--
2.20.1