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| author | Nishanth Menon <nm@ti.com> | 2013-01-18 19:52:34 +0000 |
|---|---|---|
| committer | Rafael J. Wysocki <rafael.j.wysocki@intel.com> | 2013-01-22 13:28:39 +0100 |
| commit | bcb27549f4185ca7d0168e201931613706ef2b83 (patch) | |
| tree | c9c77e26c0c9b8ef5aa4c85efff2464900283b69 /drivers/devfreq | |
| parent | 78e8eb8feab7d85f4cc215afe1457a228bf4eed9 (diff) | |
| download | lwn-bcb27549f4185ca7d0168e201931613706ef2b83.tar.gz lwn-bcb27549f4185ca7d0168e201931613706ef2b83.zip | |
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 <nm@ti.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Diffstat (limited to 'drivers/devfreq')
| -rw-r--r-- | drivers/devfreq/devfreq.c | 5 |
1 files changed, 5 insertions, 0 deletions
diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c index 53766f39aadd..3b367973a802 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) |