linux-kernel - [PATCH V2] cpufreq: Return error if ->get() failed in cpufreq_update

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Date:	Tue, 25 Feb 2014 14:29:44 +0530
From:	Viresh Kumar <viresh.kumar@...aro.org>
To:	rjw@...ysocki.net
Cc:	linaro-kernel@...ts.linaro.org, cpufreq@...r.kernel.org,
	linux-pm@...r.kernel.org, linux-kernel@...r.kernel.org,
	srivatsa.bhat@...ux.vnet.ibm.com,
	Viresh Kumar <viresh.kumar@...aro.org>
Subject: [PATCH V2] cpufreq: Return error if ->get() failed in cpufreq_update_policy()

cpufreq_update_policy() calls cpufreq_driver->get() to get current frequency of
a CPU and it is not supposed to fail or return zero. Return error in case that
happens.

Signed-off-by: Viresh Kumar <viresh.kumar@...aro.org>
---
V1->V2:
- Fixed return error to EIO instead of EINVAL
- Added WARN_ON() to flag get() failing and hence removed the print message as
  well which was earlier printed during errors.
 drivers/cpufreq/cpufreq.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c
index c755b5f..bf80502 100644
--- a/drivers/cpufreq/cpufreq.c
+++ b/drivers/cpufreq/cpufreq.c
@@ -2139,6 +2139,11 @@ int cpufreq_update_policy(unsigned int cpu)
 	 */
 	if (cpufreq_driver->get) {
 		new_policy.cur = cpufreq_driver->get(cpu);
+		if (WARN_ON(!new_policy.cur)) {
+			ret = -EIO;
+			goto no_policy;
+		}
+
 		if (!policy->cur) {
 			pr_debug("Driver did not initialize current freq");
 			policy->cur = new_policy.cur;
-- 
1.7.12.rc2.18.g61b472e

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