Re: [Xen-devel] [PATCH 1/2] xen/rwlocks: call preempt_disable() when taking a rwlock

[Jan Beulich <jbeulich@xxxxxxxx>]

On 13.03.2020 09:05, Juergen Gross wrote:
> Similar to spinlocks preemption should be disabled while holding a
> rwlock.
> 
> Signed-off-by: Juergen Gross <jgross@xxxxxxxx>

Just one note/question:

> @@ -308,6 +323,7 @@ static inline void _percpu_read_unlock(percpu_rwlock_t 
> **per_cpudata,
>          return;
>      }
>      this_cpu_ptr(per_cpudata) = NULL;
> +    preempt_enable();
>      smp_wmb();
>  }

It would seem more logical to me to insert this after the smp_wmb().
Thoughts? I'll be happy to give my R-b once we've settled on this.

Jan

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