sched: Introduce task_is_running()

Replace a bunch of 'p->state == TASK_RUNNING' with a new helper:
task_is_running(p).

Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Davidlohr Bueso <dave@stgolabs.net>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
Acked-by: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20210611082838.222401495@infradead.org
diff --git a/kernel/signal.c b/kernel/signal.c
index f7c6ffc..5fc8fcf 100644
--- a/kernel/signal.c
+++ b/kernel/signal.c
@@ -4719,7 +4719,7 @@ void kdb_send_sig(struct task_struct *t, int sig)
 	}
 	new_t = kdb_prev_t != t;
 	kdb_prev_t = t;
-	if (t->state != TASK_RUNNING && new_t) {
+	if (!task_is_running(t) && new_t) {
 		spin_unlock(&t->sighand->siglock);
 		kdb_printf("Process is not RUNNING, sending a signal from "
 			   "kdb risks deadlock\n"