[PATCH 3.10 025/139] cpufreq: conservative: Allow down_threshold to take values from 1 to 10

From: Willy Tarreau
Date: Wed Nov 01 2017 - 17:58:52 EST


From: Tomasz WilczyÅski <twilczynski@xxxxxxxxx>

commit b8e11f7d2791bd9320be1c6e772a60b2aa093e45 upstream.

Commit 27ed3cd2ebf4 (cpufreq: conservative: Fix the logic in frequency
decrease checking) removed the 10 point substraction when comparing the
load against down_threshold but did not remove the related limit for the
down_threshold value. As a result, down_threshold lower than 11 is not
allowed even though values from 1 to 10 do work correctly too. The
comment ("cannot be lower than 11 otherwise freq will not fall") also
does not apply after removing the substraction.

For this reason, allow down_threshold to take any value from 1 to 99
and fix the related comment.

Fixes: 27ed3cd2ebf4 (cpufreq: conservative: Fix the logic in frequency decrease checking)
Signed-off-by: Tomasz WilczyÅski <twilczynski@xxxxxxxxx>
Acked-by: Viresh Kumar <viresh.kumar@xxxxxxxxxx>
Cc: 3.10+ <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx>
Signed-off-by: Willy Tarreau <w@xxxxxx>
---
drivers/cpufreq/cpufreq_conservative.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/cpufreq/cpufreq_conservative.c b/drivers/cpufreq/cpufreq_conservative.c
index f97cb3d..f34e819 100644
--- a/drivers/cpufreq/cpufreq_conservative.c
+++ b/drivers/cpufreq/cpufreq_conservative.c
@@ -212,8 +212,8 @@ static ssize_t store_down_threshold(struct dbs_data *dbs_data, const char *buf,
int ret;
ret = sscanf(buf, "%u", &input);

- /* cannot be lower than 11 otherwise freq will not fall */
- if (ret != 1 || input < 11 || input > 100 ||
+ /* cannot be lower than 1 otherwise freq will not fall */
+ if (ret != 1 || input < 1 || input > 100 ||
input >= cs_tuners->up_threshold)
return -EINVAL;

--
2.8.0.rc2.1.gbe9624a