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SubjectRe: [PATCH] Thermal: fix iteration over CPU frequency list
From
On Thu, Jan 24, 2013 at 7:24 AM, Gu1 <gu1@aeroxteam.fr> wrote:
> In different places in the Thermal code, the CPU frequency list is iterated
> in an incorrect way, leading to endless loops when the frequency list contains
> a CPUFREQ_TABLE_INVALID entry, which is the case by default in the the Exynos
> 4x12 cpufreq driver, for example.
>
> The frequency list is iterated with a while loop, and when a
> CPUFREQ_TABLE_INVALID entry is encountered, the continue; statement is used to
> skip it, but the index is not incremented, causing an endless loop.
>
> A similar bug was fixed by hongbo.zhang in commit:
> Thermal: fix bug of counting cpu frequencies
>
> Signed-off-by: Gu1 <gu1@aeroxteam.fr>
This changes looks fine.

Reviewed-by: Amit Daniel Kachhap <amit.daniel@samsung.com>

Thanks,
Amit Daniel

> ---
> drivers/thermal/cpu_cooling.c | 8 +++-----
> drivers/thermal/exynos_thermal.c | 9 +++++----
> 2 files changed, 8 insertions(+), 9 deletions(-)
>
> diff --git a/drivers/thermal/cpu_cooling.c b/drivers/thermal/cpu_cooling.c
> index 836828e..51acd26 100644
> --- a/drivers/thermal/cpu_cooling.c
> +++ b/drivers/thermal/cpu_cooling.c
> @@ -123,7 +123,7 @@ static int is_cpufreq_valid(int cpu)
> */
> static unsigned int get_cpu_frequency(unsigned int cpu, unsigned long level)
> {
> - int ret = 0, i = 0;
> + int ret = 0, i;
> unsigned long level_index;
> bool descend = false;
> struct cpufreq_frequency_table *table =
> @@ -131,7 +131,7 @@ static unsigned int get_cpu_frequency(unsigned int cpu, unsigned long level)
> if (!table)
> return ret;
>
> - while (table[i].frequency != CPUFREQ_TABLE_END) {
> + for (i = 0; table[i].frequency != CPUFREQ_TABLE_END; i++) {
> if (table[i].frequency == CPUFREQ_ENTRY_INVALID)
> continue;
>
> @@ -145,7 +145,6 @@ static unsigned int get_cpu_frequency(unsigned int cpu, unsigned long level)
> /*return if level matched and table in descending order*/
> if (descend && i == level)
> return table[i].frequency;
> - i++;
> }
> i--;
>
> @@ -154,13 +153,12 @@ static unsigned int get_cpu_frequency(unsigned int cpu, unsigned long level)
> level_index = i - level;
>
> /*Scan the table in reverse order and match the level*/
> - while (i >= 0) {
> + for (; i >= 0; i--) {
> if (table[i].frequency == CPUFREQ_ENTRY_INVALID)
> continue;
> /*return if level matched*/
> if (i == level_index)
> return table[i].frequency;
> - i--;
> }
> return ret;
> }
> diff --git a/drivers/thermal/exynos_thermal.c b/drivers/thermal/exynos_thermal.c
> index 224751e..fa9e1d7 100644
> --- a/drivers/thermal/exynos_thermal.c
> +++ b/drivers/thermal/exynos_thermal.c
> @@ -233,7 +233,8 @@ static int exynos_get_crit_temp(struct thermal_zone_device *thermal,
>
> static int exynos_get_frequency_level(unsigned int cpu, unsigned int freq)
> {
> - int i = 0, ret = -EINVAL;
> + int i, ret = -EINVAL;
> + unsigned int count = 0;
> struct cpufreq_frequency_table *table = NULL;
> #ifdef CONFIG_CPU_FREQ
> table = cpufreq_frequency_get_table(cpu);
> @@ -241,12 +242,12 @@ static int exynos_get_frequency_level(unsigned int cpu, unsigned int freq)
> if (!table)
> return ret;
>
> - while (table[i].frequency != CPUFREQ_TABLE_END) {
> + for (i = 0; table[i].frequency != CPUFREQ_TABLE_END; i++) {
> if (table[i].frequency == CPUFREQ_ENTRY_INVALID)
> continue;
> if (table[i].frequency == freq)
> - return i;
> - i++;
> + return count;
> + count++;
> }
> return ret;
> }
> --
> 1.8.1.1
>
> --
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