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Re: [PATCH 12/12] PM / OPP: Update Documentation to remove RCU specific bits

From Stephen Boyd <sboyd@codeaurora.org>
Newsgroups linux.kernel
Subject Re: [PATCH 12/12] PM / OPP: Update Documentation to remove RCU specific bits
Date 2017-01-09 23:40 +0100
Message-ID <sXQLE-1uM-29@gated-at.bofh.it> (permalink)
References <sLHNL-7ku-5@gated-at.bofh.it> <sLHXs-7qQ-39@gated-at.bofh.it>
Organization linux.* mail to news gateway

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On 12/07, Viresh Kumar wrote:
> @@ -137,15 +121,18 @@ functions return the matching pointer representing the opp if a match is
>  found, else returns error. These errors are expected to be handled by standard
>  error checks such as IS_ERR() and appropriate actions taken by the caller.
>  
> +Callers of these functions shall call dev_pm_opp_put() after they have used the
> +OPP. Otherwise the memory for the OPP will never get freed and result in
> +memleak.
> +
>  dev_pm_opp_find_freq_exact - Search for an OPP based on an *exact* frequency and
>  	availability. This function is especially useful to enable an OPP which
>  	is not available by default.
>  	Example: In a case when SoC framework detects a situation where a
>  	higher frequency could be made available, it can use this function to
>  	find the OPP prior to call the dev_pm_opp_enable to actually make it available.
> -	 rcu_read_lock();
>  	 opp = dev_pm_opp_find_freq_exact(dev, 1000000000, false);
> -	 rcu_read_unlock();
> +	 dev_pm_opp_put(opp);
>  	 /* dont operate on the pointer.. just do a sanity check.. */
>  	 if (IS_ERR(opp)) {
>  		pr_err("frequency not disabled!\n");
> @@ -163,9 +150,8 @@ dev_pm_opp_find_freq_floor - Search for an available OPP which is *at most* the
>  	frequency.
>  	Example: To find the highest opp for a device:
>  	 freq = ULONG_MAX;
> -	 rcu_read_lock();
>  	 dev_pm_opp_find_freq_floor(dev, &freq);
> -	 rcu_read_unlock();
> +	 dev_pm_opp_put(opp);

opp doesn't exist in the scope here. Missing an assignment during
the dev_pm_opp_find_freq_floor() call?

-- 
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum,
a Linux Foundation Collaborative Project

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Re: [PATCH 12/12] PM / OPP: Update Documentation to remove RCU  specific bits Stephen Boyd <sboyd@codeaurora.org> - 2017-01-09 23:40 +0100
  Re: [PATCH 12/12] PM / OPP: Update Documentation to remove RCU  specific bits Viresh Kumar <viresh.kumar@linaro.org> - 2017-01-10 05:40 +0100
    Re: [PATCH 12/12] PM / OPP: Update Documentation to remove RCU  specific bits Stephen Boyd <sboyd@codeaurora.org> - 2017-01-13 09:50 +0100

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