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/[email protected] Signed-off-by: Xiaoming Ni <[email protected]> Signed-off-by: Luis Chamberlain <[email protected]> Cc: Al Viro <[email protected]> Cc: Anil S Keshavamurthy <[email protected]> Cc: Antti Palosaari <[email protected]> Cc: Christian Brauner <[email protected]> Cc: "David S. Miller" <[email protected]> Cc: Eric Biederman <[email protected]> Cc: Eric Biggers <[email protected]> Cc: Iurii Zaikin <[email protected]> Cc: Kees Cook <[email protected]> Cc: Lukas Middendorf <[email protected]> Cc: Masami Hiramatsu <[email protected]> Cc: "Naveen N. Rao" <[email protected]> Cc: Stephen Kitt <[email protected]> Signed-off-by: Andrew Morton <[email protected]> Signed-off-by: Linus Torvalds <[email protected]>
ashr · Jan 22, 2022 · fdcd407 · fdcd407
1 parent d8c0418
commit fdcd407
Show file tree

Hide file tree

Showing 3 changed files with 4 additions and 5 deletions.
diff --git a/include/linux/printk.h b/include/linux/printk.h
@@ -183,10 +183,6 @@ extern bool printk_timed_ratelimit(unsigned long *caller_jiffies,
 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);

diff --git a/kernel/printk/internal.h b/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

diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c
@@ -171,7 +171,7 @@ static int __init control_devkmsg(char *str)
 __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_table *table, int write,
 
 	return 0;
 }
+#endif /* CONFIG_PRINTK && CONFIG_SYSCTL */
 
 /* Number of registered extended console drivers. */
 static int nr_ext_console_drivers;