Re: [PATCH] cpufreq: s3c64xx: Remove pointless NULL check in s3c64xx_cpufreq_driver_init

Viresh Kumar
2019-10-23T03:23:13Z

On 22-10-19, 17:09, Nathan Chancellor wrote:
> When building with Clang + -Wtautological-pointer-compare:
>
> drivers/cpufreq/s3c64xx-cpufreq.c:152:6: warning: comparison of array
> 's3c64xx_freq_table' equal to a null pointer is always false
> [-Wtautological-pointer-compare]
> if (s3c64xx_freq_table == NULL) {
> ^~~~~~~~~~~~~~~~~~ ~~~~
> 1 warning generated.
>
> The definition of s3c64xx_freq_table is surrounded by an ifdef
> directive for CONFIG_CPU_S3C6410, which is always true for this driver
> because it depends on it in drivers/cpufreq/Kconfig.arm (and if it
> weren't, there would be a build error because s3c64xx_freq_table would
> not be a defined symbol).
>
> Resolve this warning by removing the unnecessary NULL check because it
> is always false as Clang notes. While we are at it, remove the
> unnecessary ifdef conditional because it is always true.
>
> Fixes: b3748ddd8056 ("[ARM] S3C64XX: Initial support for DVFS")

+broonie, who wrote this patch to see his views on why he kept it like
this.

> Link: https://github.com/ClangBuiltLinux/linux/issues/748
> Signed-off-by: Nathan Chancellor <natechancellor@gmail.com>
> ---
> drivers/cpufreq/s3c64xx-cpufreq.c | 7 -------
> 1 file changed, 7 deletions(-)
>
> diff --git a/drivers/cpufreq/s3c64xx-cpufreq.c b/drivers/cpufreq/s3c64xx-cpufreq.c
> index af0c00dabb22..c6bdfc308e99 100644
> --- a/drivers/cpufreq/s3c64xx-cpufreq.c
> +++ b/drivers/cpufreq/s3c64xx-cpufreq.c
> @@ -19,7 +19,6 @@
> static struct regulator *vddarm;
> static unsigned long regulator_latency;
>
> -#ifdef CONFIG_CPU_S3C6410
> struct s3c64xx_dvfs {
> unsigned int vddarm_min;
> unsigned int vddarm_max;
> @@ -48,7 +47,6 @@ static struct cpufreq_frequency_table s3c64xx_freq_table[] = {
> { 0, 4, 800000 },
> { 0, 0, CPUFREQ_TABLE_END },
> };
> -#endif
>
> static int s3c64xx_cpufreq_set_target(struct cpufreq_policy *policy,
> unsigned int index)
> @@ -149,11 +147,6 @@ static int s3c64xx_cpufreq_driver_init(struct cpufreq_policy *policy)
> if (policy->cpu != 0)
> return -EINVAL;
>
> - if (s3c64xx_freq_table == NULL) {
> - pr_err("No frequency information for this CPU\n");
> - return -ENODEV;
> - }
> -
> policy->clk = clk_get(NULL, "armclk");
> if (IS_ERR(policy->clk)) {
> pr_err("Unable to obtain ARMCLK: %ld\n",
> --
> 2.23.0

--
viresh