From ce1bcfe94db895cbd6876e176af5824742b29e25 Mon Sep 17 00:00:00 2001
From: Viresh Kumar <viresh.kumar@linaro.org>
Date: Fri, 2 Jan 2015 12:34:35 +0530
Subject: [PATCH] cpufreq: check cpufreq_policy_list instead of scanning
 policies for all CPUs

CPUFREQ_STICKY flag is set by drivers which don't want to get unregistered
even if cpufreq-core isn't able to initialize policy for any CPU.

When this flag isn't set, we try to unregister the driver. To find out
which CPUs are registered and which are not, we try to check per_cpu
cpufreq_cpu_data for all CPUs. Because we have a list of valid policies
available now, we better check if the list is empty or not instead of
the 'for' loop. That will be much more efficient.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
---
 drivers/cpufreq/cpufreq.c | 21 +++++----------------
 1 file changed, 5 insertions(+), 16 deletions(-)

diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
index 96abdcd99424..09f333f4df88 100644
--- a/drivers/cpufreq/cpufreq.c
+++ b/drivers/cpufreq/cpufreq.c
@@ -2455,23 +2455,12 @@ int cpufreq_register_driver(struct cpufreq_driver *driver_data)
 	if (ret)
 		goto err_boost_unreg;
 
-	if (!(cpufreq_driver->flags & CPUFREQ_STICKY)) {
-		int i;
-		ret = -ENODEV;
-
-		/* check for at least one working CPU */
-		for (i = 0; i < nr_cpu_ids; i++)
-			if (cpu_possible(i) && per_cpu(cpufreq_cpu_data, i)) {
-				ret = 0;
-				break;
-			}
-
+	if (!(cpufreq_driver->flags & CPUFREQ_STICKY) &&
+	    list_empty(&cpufreq_policy_list)) {
 		/* if all ->init() calls failed, unregister */
-		if (ret) {
-			pr_debug("no CPU initialized for driver %s\n",
-				 driver_data->name);
-			goto err_if_unreg;
-		}
+		pr_debug("%s: No CPU initialized for driver %s\n", __func__,
+			 driver_data->name);
+		goto err_if_unreg;
 	}
 
 	register_hotcpu_notifier(&cpufreq_cpu_notifier);