Date: Mon, 24 Nov 2014 21:41:00 +0100 (CET)
From: Thomas Gleixner <tglx@linutronix.de>
To: Daniel Thompson <daniel.thompson@linaro.org>
cc: Jason Cooper <jason@lakedaemon.net>, Russell King <linux@arm.linux.org.uk>,
        linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
        patches@linaro.org, linaro-kernel@lists.linaro.org,
        John Stultz <john.stultz@linaro.org>,
        Sumit Semwal <sumit.semwal@linaro.org>,
        Dirk Behme <dirk.behme@de.bosch.com>,
        Daniel Drake <drake@endlessm.com>,
        Dmitry Pervushin <dpervushin@gmail.com>,
        Marc Zyngier <marc.zyngier@arm.com>
Subject: Re: [PATCH 3.18-rc3 v8 1/4] irqchip: gic: Make gic_raise_softirq()
 FIQ-safe
In-Reply-To: <547396D0.5030309@linaro.org>
Message-ID: <alpine.DEB.2.11.1411242139240.6439@nanos>
References: <1415183260-6389-1-git-send-email-daniel.thompson@linaro.org> <1415968543-29469-1-git-send-email-daniel.thompson@linaro.org> <1415968543-29469-2-git-send-email-daniel.thompson@linaro.org> <alpine.DEB.2.11.1411241918090.6439@nanos>
 <alpine.DEB.2.11.1411241928300.6439@nanos> <547396D0.5030309@linaro.org>
User-Agent: Alpine 2.11 (DEB 23 2013-08-11)
MIME-Version: 1.0
Content-Type: TEXT/PLAIN; charset=US-ASCII
Sender: linux-kernel-owner@vger.kernel.org

On Mon, 24 Nov 2014, Daniel Thompson wrote:
> I did want to remove the lock too. However when I reviewed this code I
> concluded the lock was still required. Without it I think it is possible
> for gic_raise_softirq() to raise an IPI on the old core *after* the code
> to migrate pending IPIs has been run.

And I bet it took you quite some time to figure that out from that
overly documented abuse of irq_controller_lock. See my other reply.

Thanks,

	tglx
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/