From: Xiaoming Ni <nixiaoming@xxxxxxxxxx> Subject: printk: fix build warning when CONFIG_PRINTK=n build warning when CONFIG_PRINTK=n kernel/printk/printk.c:175:5: warning: no previous prototype for 'devkmsg_sysctl_set_loglvl' [-Wmissing-prototypes] devkmsg_sysctl_set_loglvl() is only used in sysctl.c when CONFIG_PRINTK=y, but it participates in the build when CONFIG_PRINTK=n. So add compile dependency CONFIG_PRINTK=y && CONFIG_SYSCTL=y to fix the build warning. Link: https://lkml.kernel.org/r/20211129211943.640266-5-mcgrof@xxxxxxxxxx Signed-off-by: Xiaoming Ni <nixiaoming@xxxxxxxxxx> Signed-off-by: Luis Chamberlain <mcgrof@xxxxxxxxxx> Cc: Al Viro <viro@xxxxxxxxxxxxxxxxxx> Cc: Anil S Keshavamurthy <anil.s.keshavamurthy@xxxxxxxxx> Cc: Antti Palosaari <crope@xxxxxx> Cc: Christian Brauner <christian.brauner@xxxxxxxxxx> Cc: "David S. Miller" <davem@xxxxxxxxxxxxx> Cc: Eric Biederman <ebiederm@xxxxxxxxxxxx> Cc: Eric Biggers <ebiggers@xxxxxxxxxx> Cc: Iurii Zaikin <yzaikin@xxxxxxxxxx> Cc: Kees Cook <keescook@xxxxxxxxxxxx> Cc: Lukas Middendorf <kernel@xxxxxxxxxxx> Cc: Masami Hiramatsu <mhiramat@xxxxxxxxxx> Cc: "Naveen N. Rao" <naveen.n.rao@xxxxxxxxxxxxx> Cc: Stephen Kitt <steve@xxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- include/linux/printk.h | 4 ---- kernel/printk/internal.h | 2 ++ kernel/printk/printk.c | 3 ++- 3 files changed, 4 insertions(+), 5 deletions(-) --- a/include/linux/printk.h~printk-fix-build-warning-when-config_printk=n +++ a/include/linux/printk.h @@ -183,10 +183,6 @@ extern bool printk_timed_ratelimit(unsig extern int printk_delay_msec; extern int dmesg_restrict; -extern int -devkmsg_sysctl_set_loglvl(struct ctl_table *table, int write, void *buf, - size_t *lenp, loff_t *ppos); - extern void wake_up_klogd(void); char *log_buf_addr_get(void); --- a/kernel/printk/internal.h~printk-fix-build-warning-when-config_printk=n +++ a/kernel/printk/internal.h @@ -6,6 +6,8 @@ #if defined(CONFIG_PRINTK) && defined(CONFIG_SYSCTL) void __init printk_sysctl_init(void); +int devkmsg_sysctl_set_loglvl(struct ctl_table *table, int write, + void *buffer, size_t *lenp, loff_t *ppos); #else #define printk_sysctl_init() do { } while (0) #endif --- a/kernel/printk/printk.c~printk-fix-build-warning-when-config_printk=n +++ a/kernel/printk/printk.c @@ -171,7 +171,7 @@ static int __init control_devkmsg(char * __setup("printk.devkmsg=", control_devkmsg); char devkmsg_log_str[DEVKMSG_STR_MAX_SIZE] = "ratelimit"; - +#if defined(CONFIG_PRINTK) && defined(CONFIG_SYSCTL) int devkmsg_sysctl_set_loglvl(struct ctl_table *table, int write, void *buffer, size_t *lenp, loff_t *ppos) { @@ -210,6 +210,7 @@ int devkmsg_sysctl_set_loglvl(struct ctl return 0; } +#endif /* CONFIG_PRINTK && CONFIG_SYSCTL */ /* Number of registered extended console drivers. */ static int nr_ext_console_drivers; _
