printk: Avoid irq_work for printk_deferred() on suspend

With commit ("printk: Avoid scheduling irq_work on suspend") the
implementation of printk_get_console_flush_type() was modified to
avoid offloading when irq_work should be blocked during suspend.
Since printk uses the returned flush type to determine what
flushing methods are used, this was thought to be sufficient for
avoiding irq_work usage during the suspend phase.

However, vprintk_emit() implements a hack to support
printk_deferred(). In this hack, the returned flush type is
adjusted to make sure no legacy direct printing occurs when
printk_deferred() was used.

Because of this hack, the legacy offloading flushing method can
still be used, causing irq_work to be queued when it should not
be.

Adjust the vprintk_emit() hack to also consider
@console_irqwork_blocked so that legacy offloading will not be
chosen when irq_work should be blocked.

Link: https://lore.kernel.org/lkml/87fra90xv4.fsf@jogness.linutronix.de
Signed-off-by: John Ogness <john.ogness@linutronix.de>
Fixes: 26873e3 ("printk: Avoid scheduling irq_work on suspend")
Reviewed-by: Petr Mladek <pmladek@suse.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>

Author: jogness

kernel/printk/printk.c

@@ -2393,7 +2393,7 @@ asmlinkage int vprintk_emit(int facility, int level,
 	/* If called from the scheduler, we can not call up(). */
 	if (level == LOGLEVEL_SCHED) {
 		level = LOGLEVEL_DEFAULT;
-		ft.legacy_offload |= ft.legacy_direct;
+		ft.legacy_offload |= ft.legacy_direct && !console_irqwork_blocked;
 		ft.legacy_direct = false;
 	}