Re: [PATCH RFC 08/26] locking: Remove spin_unlock_wait() generic definitions

From: Linus Torvalds
Date: Mon Jul 03 2017 - 18:49:59 EST

On Mon, Jul 3, 2017 at 3:30 PM, Paul E. McKenney
<paulmck@xxxxxxxxxxxxxxxxxx> wrote:
> That certainly is one interesting function, isn't it? I wonder what
> happens if you replace the raw_spin_is_locked() calls with an
> unlock under a trylock check? ;-)

Deadlock due to interrupts again?

Didn't your spin_unlock_wait() patches teach you anything? Checking
state is fundamentally different from taking the lock. Even a trylock.

I guess you could try with the irqsave versions. But no, we're not doing that.