Re: [PATCH 12/12] PM / OPP: Update Documentation to remove RCU specific bits
From: Stephen Boyd
Date: Mon Jan 09 2017 - 17:39:44 EST
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?
--
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