static_call: Use RCU in all users of __module_text_address().

__module_text_address() can be invoked within a RCU section, there is no
requirement to have preemption disabled.

Replace the preempt_disable() section around __module_text_address()
with RCU.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/r/20250108090457.512198-28-bigeasy@linutronix.de
Signed-off-by: Petr Pavlu <petr.pavlu@suse.com>

Author: Sebastian Andrzej Siewior

kernel/static_call_inline.c

@@ -325,13 +325,12 @@ static int __static_call_mod_text_reserved(void *start, void *end)
 	struct module *mod;
 	int ret;
 
-	preempt_disable();
-	mod = __module_text_address((unsigned long)start);
-	WARN_ON_ONCE(__module_text_address((unsigned long)end) != mod);
-	if (!try_module_get(mod))
-		mod = NULL;
-	preempt_enable();
-
+	scoped_guard(rcu) {
+		mod = __module_text_address((unsigned long)start);
+		WARN_ON_ONCE(__module_text_address((unsigned long)end) != mod);
+		if (!try_module_get(mod))
+			mod = NULL;
+	}
 	if (!mod)
 		return 0;