printk: Rename console_replay_all() and update context

Rename console_replay_all() to console_try_replay_all() to make
clear that the implementation is best effort. Also, the function
should not be called in NMI context as it takes locks, so update
the comment in code.

Fixes: 693f75b ("printk: Add function to replay kernel log on consoles")
Fixes: 1b74348 ("tty/sysrq: Replay kernel log messages on consoles via sysrq")
Suggested-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Shimoyashiki Taichi <taichi.shimoyashiki@sony.com>
Signed-off-by: Sreenath Vijayan <sreenath.vijayan@sony.com>
Link: https://lore.kernel.org/r/Zlguq/wU21Z8MqI4@sreenath.vijayan@sony.com
Reviewed-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>

drivers/tty/sysrq.c

@@ -452,7 +452,7 @@ static const struct sysrq_key_op sysrq_unrt_op = {
 
 static void sysrq_handle_replay_logs(u8 key)
 {
-	console_replay_all();
+	console_try_replay_all();
 }
 static struct sysrq_key_op sysrq_replay_logs_op = {
 	.handler        = sysrq_handle_replay_logs,

include/linux/printk.h

@@ -195,7 +195,7 @@ void show_regs_print_info(const char *log_lvl);
 extern asmlinkage void dump_stack_lvl(const char *log_lvl) __cold;
 extern asmlinkage void dump_stack(void) __cold;
 void printk_trigger_flush(void);
-void console_replay_all(void);
+void console_try_replay_all(void);
 #else
 static inline __printf(1, 0)
 int vprintk(const char *s, va_list args)
@@ -275,7 +275,7 @@ static inline void dump_stack(void)
 static inline void printk_trigger_flush(void)
 {
 }
-static inline void console_replay_all(void)
+static inline void console_try_replay_all(void)
 {
 }
 #endif

kernel/printk/printk.c

@@ -4314,15 +4314,15 @@ void kmsg_dump_rewind(struct kmsg_dump_iter *iter)
 EXPORT_SYMBOL_GPL(kmsg_dump_rewind);
 
 /**
- * console_replay_all - replay kernel log on consoles
+ * console_try_replay_all - try to replay kernel log on consoles
  *
  * Try to obtain lock on console subsystem and replay all
  * available records in printk buffer on the consoles.
  * Does nothing if lock is not obtained.
  *
- * Context: Any context.
+ * Context: Any, except for NMI.
  */
-void console_replay_all(void)
+void console_try_replay_all(void)
 {
 	if (console_trylock()) {
 		__console_rewind_all();