From mboxrd@z Thu Jan  1 00:00:00 1970
From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Date: Tue, 07 May 2013 07:25:20 +0000
Subject: Re: [PATCH] powerpc: Make hard_irq_disable() do the right thing vs. irq tracing
Message-Id: <1367911520.5769.12.camel@pasglop>
List-Id: <kvm-ppc.vger.kernel.org>
References: <1367910242.5769.11.camel@pasglop> <5188AA2D.1040802@windriver.com>
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To: "tiejun.chen" <tiejun.chen@windriver.com>
Cc: Scott Wood <scottwood@freescale.com>, Mihai Caraman <mihai.caraman@freescale.com>, linuxppc-dev@lists.ozlabs.org, kvm-ppc@vger.kernel.org

On Tue, 2013-05-07 at 15:15 +0800, tiejun.chen wrote:
> Could we simplify this as follows:
> 
> +#define hard_irq_disable()     do {                    \
> +       __hard_irq_disable();                           \
> +       if (get_paca()->soft_enabled) {                 \
> +               trace_hardirqs_off();                   \
> +               get_paca()->soft_enabled = 0;           \
> +       }                                               \
> +       get_paca()->irq_happened |= PACA_IRQ_HARD_DIS;  \
> +} while(0)

I'd rather not. When lockdep is not enabled trace_hardirqs_off() is a
nop and thus we have no conditional at all which is arguably better...

Cheers,
Ben.