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Date: Mon, 21 Sep 2015 16:29:38 +0100
From: Will Deacon <will.deacon@arm.com>
To: Andrzej Hajda <a.hajda@samsung.com>
Cc: "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>,
        Marek Szyprowski <m.szyprowski@samsung.com>,
        Suzuki Poulose <Suzuki.Poulose@arm.com>,
        Punit Agrawal <Punit.Agrawal@arm.com>, Arnd Bergmann <arnd@arndb.de>,
        Mark Rutland <Mark.Rutland@arm.com>
Subject: Re: [PATCH 01/38] arm-cci: fix handling cpumask_any_but return value
Message-ID: <20150921152938.GA7356@arm.com>
References: <1442842450-29769-1-git-send-email-a.hajda@samsung.com>
 <1442842450-29769-2-git-send-email-a.hajda@samsung.com>
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On Mon, Sep 21, 2015 at 02:33:33PM +0100, Andrzej Hajda wrote:
> cpumask_any_but returns value >= nr_cpu_ids if there are no more CPUs.
> 
> The problem has been detected using proposed semantic patch
> scripts/coccinelle/tests/unsigned_lesser_than_zero.cocci [1].
> 
> [1]: http://permalink.gmane.org/gmane.linux.kernel/2038576
> 
> Signed-off-by: Andrzej Hajda <a.hajda@samsung.com>
> ---
>  drivers/bus/arm-cci.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/bus/arm-cci.c b/drivers/bus/arm-cci.c
> index 577cc4b..22754d0 100644
> --- a/drivers/bus/arm-cci.c
> +++ b/drivers/bus/arm-cci.c
> @@ -1314,7 +1314,7 @@ static int cci_pmu_cpu_notifier(struct notifier_block *self,
>  		if (!cpumask_test_and_clear_cpu(cpu, &cci_pmu->cpus))
>  			break;
>  		target = cpumask_any_but(cpu_online_mask, cpu);
> -		if (target < 0) // UP, last CPU
> +		if (target >= nr_cpu_ids) // UP, last CPU

We could also make target an int, to match the return type of
cpumask_any_but (on top of this change).

Regardless,

  Acked-by: Will Deacon <will.deacon@arm.com>

Will