From: Rasmus Villemoes Subject: lib/string.c: simplify str[c]spn Use strchr(), which makes them a lot shorter, and more obviously symmetric in their treatment of accept/reject. It also saves a little bit of .text; bloat-o-meter for an arm build says Function old new delta strcspn 92 76 -16 strspn 108 76 -32 While here, also remove a stray empty line before EXPORT_SYMBOL(). Link: https://lkml.kernel.org/r/20220328224119.3003834-2-linux@rasmusvillemoes.dk Signed-off-by: Rasmus Villemoes Cc: Andy Shevchenko Signed-off-by: Andrew Morton --- lib/string.c | 25 ++++++------------------- 1 file changed, 6 insertions(+), 19 deletions(-) --- a/lib/string.c~lib-stringc-simplify-strspn +++ a/lib/string.c @@ -517,21 +517,13 @@ EXPORT_SYMBOL(strnlen); size_t strspn(const char *s, const char *accept) { const char *p; - const char *a; - size_t count = 0; for (p = s; *p != '\0'; ++p) { - for (a = accept; *a != '\0'; ++a) { - if (*p == *a) - break; - } - if (*a == '\0') - return count; - ++count; + if (!strchr(accept, *p)) + break; } - return count; + return p - s; } - EXPORT_SYMBOL(strspn); #endif @@ -544,17 +536,12 @@ EXPORT_SYMBOL(strspn); size_t strcspn(const char *s, const char *reject) { const char *p; - const char *r; - size_t count = 0; for (p = s; *p != '\0'; ++p) { - for (r = reject; *r != '\0'; ++r) { - if (*p == *r) - return count; - } - ++count; + if (strchr(reject, *p)) + break; } - return count; + return p - s; } EXPORT_SYMBOL(strcspn); #endif _