Merge tag 'printk-for-7.3-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/printk/linux

Pull printk fixes from Petr Mladek:

 - Use lazy irq_work for waking printk kthreads

 - Flush pending irq_work before destroying printk kthreads

 - Remove redundant WARN() when a printk kthread can't be created

 - Typo fix

* tag 'printk-for-7.3-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/printk/linux:
  printk/nbcon: Change nbcon_irq_work to IRQ_WORK_LAZY
  printk/nbcon: Flush nbcon_irq_work in nbcon_free()
  console: fix /dev/kmsg reference in flags kernel doc
  printk: Don't WARN on kthread_run failure.

include/linux/console.h

@@ -173,7 +173,7 @@ static inline void con_debug_leave(void) { }
  * @CON_BRL:		Indicates a braille device which is exempt from
  *			receiving the printk spam for obvious reasons.
  * @CON_EXTENDED:	The console supports the extended output format of
- *			/dev/kmesg which requires a larger output buffer.
+ *			/dev/kmsg which requires a larger output buffer.
  * @CON_SUSPENDED:	Indicates if a console is suspended. If true, the
  *			printing callbacks must not be called.
  * @CON_NBCON:		Console can operate outside of the legacy style console_lock

kernel/printk/nbcon.c

@@ -1382,7 +1382,7 @@ bool nbcon_kthread_create(struct console *con)
 		return true;
 
 	kt = kthread_run(nbcon_kthread_func, con, "pr/%s%d", con->name, con->index);
-	if (WARN_ON(IS_ERR(kt))) {
+	if (IS_ERR(kt)) {
 		con_printk(KERN_ERR, con, "failed to start printing thread\n");
 		return false;
 	}
@@ -1782,7 +1782,7 @@ bool nbcon_alloc(struct console *con)
 	}
 
 	rcuwait_init(&con->rcuwait);
-	init_irq_work(&con->irq_work, nbcon_irq_work);
+	con->irq_work = IRQ_WORK_INIT_LAZY(nbcon_irq_work);
 	atomic_long_set(&ACCESS_PRIVATE(con, nbcon_prev_seq), -1UL);
 	nbcon_state_set(con, &state);
 
@@ -1837,6 +1837,8 @@ void nbcon_free(struct console *con)
 	/* Synchronize the kthread stop. */
 	lockdep_assert_console_list_lock_held();
 
+	irq_work_sync(&con->irq_work);
+
 	if (printk_kthreads_running) {
 		nbcon_kthread_stop(con);
 

kernel/printk/printk.c

@@ -3732,7 +3732,7 @@ static bool legacy_kthread_create(void)
 	lockdep_assert_console_list_lock_held();
 
 	kt = kthread_run(legacy_kthread_func, NULL, "pr/legacy");
-	if (WARN_ON(IS_ERR(kt))) {
+	if (IS_ERR(kt)) {
 		pr_err("failed to start legacy printing thread\n");
 		return false;
 	}