Re: [PATCH v4 08/12] xen/spinlock: add another function level

[Jan Beulich <jbeulich@xxxxxxxx>]

On 12.12.2023 10:47, Juergen Gross wrote:
> @@ -377,25 +388,25 @@ void _spin_unlock_irqrestore(spinlock_t *lock, unsigned 
> long flags)
>      local_irq_restore(flags);
>  }
>  
> +static int always_inline spin_is_locked_common(const spinlock_tickets_t *t)
> +{
> +    return t->head != t->tail;
> +}
> +
>  int _spin_is_locked(const spinlock_t *lock)
>  {
> -    /*
> -     * Recursive locks may be locked by another CPU, yet we return
> -     * "false" here, making this function suitable only for use in
> -     * ASSERT()s and alike.
> -     */
> -    return lock->recurse_cpu == SPINLOCK_NO_CPU
> -           ? lock->tickets.head != lock->tickets.tail
> -           : lock->recurse_cpu == smp_processor_id();
> +    return spin_is_locked_common(&lock->tickets);
>  }

This looks like a functional change. I haven't spotted an adjustment in an
earlier patch that would make the lost case unnecessary, but even if there
was one, the removal thereof would then also want doing there, I think.

Jan