Joe Perches <j...@perches.com> 于2019年7月30日周二 上午8:16写道：
>
> On Mon, 2019-07-29 at 23:15 +0800, Chuhong Yuan wrote:
> > strncmp(str, const, len) is error-prone.
> > We had better use newly introduced
> > str_has_prefix() instead of it.
> []
> > diff --git a/kernel/printk/braille.c b/kernel/printk/braille.c
> []
> > @@ -11,10 +11,10 @@
> >
> > int _braille_console_setup(char **str, char **brl_options)
> > {
> > - if (!strncmp(*str, "brl,", 4)) {
> > + if (str_has_prefix(*str, "brl,")) {
> > *brl_options = "";
> > *str += 4;
> > - } else if (!strncmp(*str, "brl=", 4)) {
> > + } else if (str_has_prefix(*str, "brl=")) {
> > *brl_options = *str + 4;
>
> Better to get rid of the += 4 uses too by storing the result
> of str_has_prefix and using that as the addend.
>
> Perhaps
> size_t len;
>
> if ((len = str_has_prefix(*str, "brl,"))) {
> *brl_options = "";
> *str += len;
> } else if ((len = str_has_prefix(*str, "brl="))) {
> etc...
>
I find that checkpatch.pl forbids assignment in if condition.
So this seems to be infeasible...
> > *str = strchr(*brl_options, ',');
> > if (!*str) {
> > diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c
> []
> > @@ -121,13 +121,13 @@ static int __control_devkmsg(char *str)
> > if (!str)
> > return -EINVAL;
> >
> > - if (!strncmp(str, "on", 2)) {
> > + if (str_has_prefix(str, "on")) {
> > devkmsg_log = DEVKMSG_LOG_MASK_ON;
> > return 2;
> > - } else if (!strncmp(str, "off", 3)) {
> > + } else if (str_has_prefix(str, "off")) {
> > devkmsg_log = DEVKMSG_LOG_MASK_OFF;
> > return 3;
> > - } else if (!strncmp(str, "ratelimit", 9)) {
> > + } else if (str_has_prefix(str, "ratelimit")) {
> > devkmsg_log = DEVKMSG_LOG_MASK_DEFAULT;
> > return 9;
> > }
>
> here too.
>
>
