linux-kernel - Re: [PATCH] opp: cpu: Replace GFP_ATOMIC with GFP_KERNEL in dev_pm_opp_init_cpufreq

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Message-ID: <20180208144513.GW28462@vireshk-i7>
Date:   Thu, 8 Feb 2018 20:15:13 +0530
From:   Viresh Kumar <viresh.kumar@...aro.org>
To:     Jia-Ju Bai <baijiaju1990@...il.com>
Cc:     vireshk@...nel.org, nm@...com, sboyd@...eaurora.org,
        linux-pm@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] opp: cpu: Replace GFP_ATOMIC with GFP_KERNEL in
 dev_pm_opp_init_cpufreq_table

On 26-01-18, 16:48, Jia-Ju Bai wrote:
> After checking all possible call chains to 
> dev_pm_opp_init_cpufreq_table() here,
> my tool finds that this function is never called in atomic context, 
> namely never in an interrupt handler or holding a spinlock.
> And dev_pm_opp_init_cpufreq_table() calls dev_pm_opp_get_opp_count(), 
> which calls mutex_lock that can sleep.
> It indicates that atmtcp_v_send() can call functions which may sleep.
> Thus GFP_ATOMIC is not necessary, and it can be replaced with GFP_KERNEL.
> 
> This is found by a static analysis tool named DCNS written by myself.
> 
> Signed-off-by: Jia-Ju Bai <baijiaju1990@...il.com>
> ---
>  drivers/opp/cpu.c |    2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/opp/cpu.c b/drivers/opp/cpu.c
> index 2d87bc1..0c09107 100644
> --- a/drivers/opp/cpu.c
> +++ b/drivers/opp/cpu.c
> @@ -55,7 +55,7 @@ int dev_pm_opp_init_cpufreq_table(struct device *dev,
>  	if (max_opps <= 0)
>  		return max_opps ? max_opps : -ENODATA;
>  
> -	freq_table = kcalloc((max_opps + 1), sizeof(*freq_table), GFP_ATOMIC);
> +	freq_table = kcalloc((max_opps + 1), sizeof(*freq_table), GFP_KERNEL);
>  	if (!freq_table)
>  		return -ENOMEM;

Applied thanks.

-- 
viresh