Re: [PATCH 01/17] powerpc/qspinlock: powerpc qspinlock implementation

[Jordan NIethe <jniethe5@gmail.com>]

On Thu, 2022-07-28 at 16:31 +1000, Nicholas Piggin wrote:
<snip>
> -#define queued_spin_lock queued_spin_lock
>  
> -static inline void queued_spin_unlock(struct qspinlock *lock)
> +static __always_inline int queued_spin_trylock(struct qspinlock *lock)
>  {
> -	if (!IS_ENABLED(CONFIG_PARAVIRT_SPINLOCKS) || !is_shared_processor())
> -		smp_store_release(&lock->locked, 0);
> -	else
> -		__pv_queued_spin_unlock(lock);
> +	if (atomic_cmpxchg_acquire(&lock->val, 0, 1) == 0)
> +		return 1;
> +	return 0;

optional style nit: return (atomic_cmpxchg_acquire(&lock->val, 0, 1) == 0);