From mboxrd@z Thu Jan  1 00:00:00 1970
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Date: Thu, 07 Dec 2006 00:03:17 +0100
From: Jan Kiszka <jan.kiszka@domain.hid>
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Subject: [Xenomai-core] Re: [patch] memory barriers in intr.c ::
	xnintr_lock/unlock()
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Dmitry Adamushko wrote:
> Hello,
>=20
> following the recent discussion with Jan, here is a patch that aims at
> allowing xnintr_lock/unlock actually do what they were supposed to do i=
n
> the first instance.
>=20

[...]

>=20
> --- xenomai/ksrc/nucleus/intr-old.c	2006-11-12 00:17:56.000000000 +0100=

> +++ xenomai/ksrc/nucleus/intr.c	2006-11-12 00:22:15.000000000 +0100
> @@ -135,12 +135,14 @@ static inline void xnintr_shirq_lock(xni
>  {
>  #ifdef CONFIG_SMP
>  	xnarch_atomic_inc(&shirq->active);
> +	xnarch_memory_barrier();
>  #endif
>  }
> =20
>  static inline void xnintr_shirq_unlock(xnintr_shirq_t *shirq)
>  {
>  #ifdef CONFIG_SMP
> +	xnarch_memory_barrier();
>  	xnarch_atomic_dec(&shirq->active);
>  #endif
>  }

As Dmitry and I are still a bit undecided about who to evolve such RCU
locks best but still face this SMP bug in the current code, we are
suggesting now to merge the patch above as-is for 2.3 - before things
get lost for the release.

Jan


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