On Fri, 2019-08-02 at 09:47 +0800, Chuhong Yuan wrote:
> 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.
[]
> diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c
[]
> @@ -118,18 +118,20 @@ static unsigned int __read_mostly devkmsg_log =
> DEVKMSG_LOG_MASK_DEFAULT;
>
> static int __control_devkmsg(char *str)
> {
> + size_t len;
> +
> if (!str)
> return -EINVAL;
>
> - if (!strncmp(str, "on", 2)) {
> + if ((len = str_has_prefix(str, "on"))) {
> devkmsg_log = DEVKMSG_LOG_MASK_ON;
> - return 2;
> - } else if (!strncmp(str, "off", 3)) {
> + return len;
> + } else if ((len = str_has_prefix(str, "off"))) {
> devkmsg_log = DEVKMSG_LOG_MASK_OFF;
> - return 3;
> - } else if (!strncmp(str, "ratelimit", 9)) {
> + return len;
> + } else if ((len = str_has_prefix(str, "ratelimit"))) {
> devkmsg_log = DEVKMSG_LOG_MASK_DEFAULT;
> - return 9;
> + return len;
> }
> return -EINVAL;
> }
All of the else uses above could also be removed.
