[PATCH 2.6.24-rc8] cpufreq: fix obvious condition statement error

[Yi Yang]

The function __cpufreq_set_policy in file drivers/cpufreq/cpufreq.c
has a very obvious error:

        if (policy->min > data->min && policy->min > policy->max) {
                ret = -EINVAL;
                goto error_out;
        }

This condtion statement is wrong because it returns -EINVAL only if
policy->min is greater than policy->max (in this case, 
"policy->min > data->min" is true for ever.). In fact, it should
return -EINVAL as well if policy->max is less than data->min.

The correct condition should be:

        if (policy->min > data->max || policy->max < data->min) {

The following test result testifies the above conclusion:

Before applying this patch:

[EMAIL PROTECTED] /]# cat 
/sys/devices/system/cpu/cpu0/cpufreq/scaling_available_frequencies
2394000 1596000
[EMAIL PROTECTED] /]# echo 1596000 > 
/sys/devices/system/cpu/cpu0/cpufreq/scaling_max_freq
[EMAIL PROTECTED] /]# cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_max_freq
1596000
[EMAIL PROTECTED] /]# cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_min_freq
1596000
[EMAIL PROTECTED] /]# echo "2000000" > 
/sys/devices/system/cpu/cpu0/cpufreq/scaling_min_freq
-bash: echo: write error: Invalid argument
[EMAIL PROTECTED] /]# cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_min_freq
1596000
[EMAIL PROTECTED] /]# echo "0" > 
/sys/devices/system/cpu/cpu0/cpufreq/scaling_max_freq
[EMAIL PROTECTED] /]# cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_max_freq
1596000
[EMAIL PROTECTED] /]# echo "1595000" > 
/sys/devices/system/cpu/cpu0/cpufreq/scaling_max_freq
[EMAIL PROTECTED] /]# cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_max_freq
1596000
[EMAIL PROTECTED] /]#


After applying this patch:

[EMAIL PROTECTED] /]# cat 
/sys/devices/system/cpu/cpu0/cpufreq/scaling_available_frequencies
2394000 1596000
[EMAIL PROTECTED] /]# echo 1596000 > 
/sys/devices/system/cpu/cpu0/cpufreq/scaling_max_freq
[EMAIL PROTECTED] /]# cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_max_freq
1596000
[EMAIL PROTECTED] /]# cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_min_freq
1596000
[EMAIL PROTECTED] /]# echo "2000000" > 
/sys/devices/system/cpu/cpu0/cpufreq/scaling_min_freq
-bash: echo: write error: Invalid argument
[EMAIL PROTECTED] /]# cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_min_freq
1596000
[EMAIL PROTECTED] /]# echo "0" > 
/sys/devices/system/cpu/cpu0/cpufreq/scaling_max_freq
-bash: echo: write error: Invalid argument
[EMAIL PROTECTED] /]# echo "1595000" > 
/sys/devices/system/cpu/cpu0/cpufreq/scaling_max_freq
-bash: echo: write error: Invalid argument
[EMAIL PROTECTED] /]# cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_max_freq
1596000
[EMAIL PROTECTED] /]# echo "1596000" > 
/sys/devices/system/cpu/cpu0/cpufreq/scaling_max_freq
[EMAIL PROTECTED] /]# echo "2394000" > 
/sys/devices/system/cpu/cpu0/cpufreq/scaling_max_freq
[EMAIL PROTECTED] /]# cat /sys/devices/system/cpu/cpu0/cpufreq/scaling_max_freq
2394000
[EMAIL PROTECTED] /]


Signed-off-by: Yi Yang <[EMAIL PROTECTED]>
---
 cpufreq.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/drivers/cpufreq/cpufreq.c 2008-01-23 05:02:28.000000000 +0800
+++ b/drivers/cpufreq/cpufreq.c 2008-01-23 06:11:21.000000000 +0800
@@ -1608,7 +1608,7 @@ static int __cpufreq_set_policy(struct c
        memcpy(&policy->cpuinfo, &data->cpuinfo,
                                sizeof(struct cpufreq_cpuinfo));
 
-       if (policy->min > data->min && policy->min > policy->max) {
+       if (policy->min > data->max || policy->max < data->min) {
                ret = -EINVAL;
                goto error_out;
        }


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