once: switch to new jump label API

Switch the DO_ONCE() macro from the deprecated jump label API to the new
one.  The new one is more readable, and for DO_ONCE() it also makes the
generated code more icache-friendly: now the one-time initialization
code is placed out-of-line at the jump target, rather than at the inline
fallthrough case.

Acked-by: Hannes Frederic Sowa <hannes@stressinduktion.org>
Signed-off-by: Eric Biggers <ebiggers@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/include/linux/once.h b/include/linux/once.h
index 9c98aaa..7247249 100644
--- a/include/linux/once.h
+++ b/include/linux/once.h
@@ -5,7 +5,7 @@
 #include <linux/jump_label.h>
 
 bool __do_once_start(bool *done, unsigned long *flags);
-void __do_once_done(bool *done, struct static_key *once_key,
+void __do_once_done(bool *done, struct static_key_true *once_key,
 		    unsigned long *flags);
 
 /* Call a function exactly once. The idea of DO_ONCE() is to perform
@@ -38,8 +38,8 @@ void __do_once_done(bool *done, struct static_key *once_key,
 	({								     \
 		bool ___ret = false;					     \
 		static bool ___done = false;				     \
-		static struct static_key ___once_key = STATIC_KEY_INIT_TRUE; \
-		if (static_key_true(&___once_key)) {			     \
+		static DEFINE_STATIC_KEY_TRUE(___once_key);		     \
+		if (static_branch_unlikely(&___once_key)) {		     \
 			unsigned long ___flags;				     \
 			___ret = __do_once_start(&___done, &___flags);	     \
 			if (unlikely(___ret)) {				     \