linux-kernel - [PATCH] cpufreq: cpufreq_stats: make last

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Message-ID: <1505506402-11497-1-git-send-email-byan@nvidia.com>
Date:   Fri, 15 Sep 2017 13:13:22 -0700
From:   Bo Yan <byan@...dia.com>
To:     <viresh.kumar@...aro.org>, <rjw@...ysocki.net>,
        <linux-pm@...r.kernel.org>
CC:     <linux-kernel@...r.kernel.org>, Bo Yan <byan@...dia.com>
Subject: [PATCH] cpufreq: cpufreq_stats: make last_index signed int

It is possible for last_index to get a -1 if current frequency
is not found in the freq table when stats is created. If the
function "cpufreq_stats_update" is called before last_index is
updated with a valid value, the "-1" will be used as index to
update stats->time_in_state, triggering an exception.

Change the type of last_index of cpufreq_stats from unsigned int
to signed int.

Move last_time to location right before time_in_state. This helps
save 4 bytes in a LP64 programming model.

Signed-off-by: Bo Yan <byan@...dia.com>
---
 drivers/cpufreq/cpufreq_stats.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/cpufreq/cpufreq_stats.c b/drivers/cpufreq/cpufreq_stats.c
index e75880eb037d..a6838f5a2004 100644
--- a/drivers/cpufreq/cpufreq_stats.c
+++ b/drivers/cpufreq/cpufreq_stats.c
@@ -18,10 +18,10 @@ static DEFINE_SPINLOCK(cpufreq_stats_lock);

 struct cpufreq_stats {
 	unsigned int total_trans;
-	unsigned long long last_time;
 	unsigned int max_state;
 	unsigned int state_num;
-	unsigned int last_index;
+	int last_index;
+	unsigned long long last_time;
 	u64 *time_in_state;
 	unsigned int *freq_table;
 	unsigned int *trans_table;
-- 
2.7.4