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Date:   Tue, 14 Apr 2020 12:28:10 -0400
From:   Steven Rostedt <rostedt@goodmis.org>
To:     Qais Yousef <qais.yousef@arm.com>
Cc:     Ingo Molnar <mingo@redhat.com>,
        Peter Zijlstra <peterz@infradead.org>,
        Juri Lelli <juri.lelli@redhat.com>,
        Vincent Guittot <vincent.guittot@linaro.org>,
        Dietmar Eggemann <dietmar.eggemann@arm.com>,
        Ben Segall <bsegall@google.com>, Mel Gorman <mgorman@suse.de>,
        Andrew Morton <akpm@linux-foundation.org>,
        Thomas Gleixner <tglx@linutronix.de>,
        Yury Norov <yury.norov@gmail.com>,
        Paul Turner <pjt@google.com>,
        Alexey Dobriyan <adobriyan@gmail.com>,
        Josh Don <joshdon@google.com>,
        Pavan Kondeti <pkondeti@codeaurora.org>,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH 3/4] cpumask: Convert cpumask_any_but() to the new
 random function
Message-ID: <20200414122810.4b83ddd2@gandalf.local.home>
In-Reply-To: <20200414150556.10920-4-qais.yousef@arm.com>
References: <20200414150556.10920-1-qais.yousef@arm.com>
        <20200414150556.10920-4-qais.yousef@arm.com>
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On Tue, 14 Apr 2020 16:05:55 +0100
Qais Yousef <qais.yousef@arm.com> wrote:

> +int cpumask_any_but(const struct cpumask *srcp, unsigned int cpu)
> +{
> +	unsigned int i;
> +
> +	cpumask_check(cpu);
> +
> +	for_each_cpu(i, srcp) {
> +		i = cpumask_any(srcp);

Hmm, if the current CPU is the last CPU in the mask, and cpumask_any()
happens to return it, what happens?

> +		if (i != cpu)
> +			return i;

We loop again, and wouldn't i being the last CPU in the mask cause this
loop to exit, and return nr_cpu_ids?

-- Steve

> +	}
> +
> +	return nr_cpu_ids;
> +}