From bcb27549f4185ca7d0168e201931613706ef2b83 Mon Sep 17 00:00:00 2001 From: Nishanth Menon Date: Fri, 18 Jan 2013 19:52:34 +0000 Subject: [PATCH] PM / devfreq: add locking documentation for recommended_opp OPP pointers are protected by RCU locks, the pointer validity is permissible only under the section of rcu_read_lock to rcu_read_unlock Add documentation to the effect. Signed-off-by: Nishanth Menon Signed-off-by: Rafael J. Wysocki --- drivers/devfreq/devfreq.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c index 53766f3..3b36797 100644 --- a/drivers/devfreq/devfreq.c +++ b/drivers/devfreq/devfreq.c @@ -994,6 +994,11 @@ module_exit(devfreq_exit); * @freq: The frequency given to target function * @flags: Flags handed from devfreq framework. * + * Locking: This function must be called under rcu_read_lock(). opp is a rcu + * protected pointer. The reason for the same is that the opp pointer which is + * returned will remain valid for use with opp_get_{voltage, freq} only while + * under the locked area. The pointer returned must be used prior to unlocking + * with rcu_read_unlock() to maintain the integrity of the pointer. */ struct opp *devfreq_recommended_opp(struct device *dev, unsigned long *freq, u32 flags) -- 2.7.4