parse_affn_scope() uses strncasecmp() with the length of the candidate name, which means it only checks if the input *starts with* a known scope name. Given that the upcoming diff will create "cache_shard" affinity scope, writing "cache_shard" to a workqueue's affinity_scope sysfs attribute always matches "cache" first, making it impossible to select "cache_shard" via sysfs, so, this fix enable it to distinguish "cache" and "cache_shard" Fix by replacing the hand-rolled prefix matching loop with sysfs_match_string(), which uses sysfs_streq() for exact matching (modulo trailing newlines). Also add the missing const qualifier to the wq_affn_names[] array declaration. Note that sysfs_streq() is case-sensitive, unlike the previous strncasecmp() approach. This is intentional and consistent with how other sysfs attributes handle string matching in the kernel. Signed-off-by: Breno Leitao --- kernel/workqueue.c | 10 ++-------- 1 file changed, 2 insertions(+), 8 deletions(-) diff --git a/kernel/workqueue.c b/kernel/workqueue.c index aeaec79bc09c4..028afc3d14e59 100644 --- a/kernel/workqueue.c +++ b/kernel/workqueue.c @@ -404,7 +404,7 @@ struct work_offq_data { u32 flags; }; -static const char *wq_affn_names[WQ_AFFN_NR_TYPES] = { +static const char * const wq_affn_names[WQ_AFFN_NR_TYPES] = { [WQ_AFFN_DFL] = "default", [WQ_AFFN_CPU] = "cpu", [WQ_AFFN_SMT] = "smt", @@ -7063,13 +7063,7 @@ int workqueue_unbound_housekeeping_update(const struct cpumask *hk) static int parse_affn_scope(const char *val) { - int i; - - for (i = 0; i < ARRAY_SIZE(wq_affn_names); i++) { - if (!strncasecmp(val, wq_affn_names[i], strlen(wq_affn_names[i]))) - return i; - } - return -EINVAL; + return sysfs_match_string(wq_affn_names, val); } static int wq_affn_dfl_set(const char *val, const struct kernel_param *kp) -- 2.52.0