On Wed, Aug 28, 2024 at 10:37:19AM -0400, Mathieu Desnoyers wrote:

To cover scenarios where the scope of the guard differs from the scope
of its activation, introduce DEFINE_INACTIVE_GUARD() and activate_guard().

Here is an example use for a conditionally activated guard variable:

void func(bool a)
{
	DEFINE_INACTIVE_GUARD(preempt_notrace, myguard);

	[...]
	if (a) {
		might_sleep();
		activate_guard(preempt_notrace, myguard)();
	}
	[ protected code ]
}

So... I more or less proposed this much earlier:

  https://lore.kernel.org/all/20230919131038.GC39346@noisy.programming.kicks-ass.net/T/#mb7b84212619ac743dfe4d2cc81decce451586b27 (local)

and Linus took objection to similar patterns. But perhaps my naming
wasn't right.