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>
Git-commit: bcb27549f4185ca7d0168e201931613706ef2b83
Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
Change-Id: I2c0336d9941f2e1ddb42d97342c95cd61c96af44
Signed-off-by: Jeremy Gebben <jgebben@codeaurora.org>
diff --git a/drivers/devfreq/devfreq.c b/drivers/devfreq/devfreq.c
index a04f255..89d779c 100644
--- a/drivers/devfreq/devfreq.c
+++ b/drivers/devfreq/devfreq.c
@@ -994,6 +994,11 @@
* @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)