From mboxrd@z Thu Jan 1 00:00:00 1970 From: Zhang Rui Subject: Re: [PATCH] thermal: use cpumask_var_t for on-stack cpu masks Date: Fri, 10 Feb 2017 16:38:47 +0800 Message-ID: <1486715927.2645.7.camel@intel.com> References: <20170202144821.3721926-1-arnd@arndb.de> Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 8bit Return-path: In-Reply-To: <20170202144821.3721926-1-arnd@arndb.de> Sender: linux-kernel-owner@vger.kernel.org To: Arnd Bergmann , Amit Daniel Kachhap , Viresh Kumar , Javi Merino , Eduardo Valentin Cc: "Rafael J. Wysocki" , linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org List-Id: linux-pm@vger.kernel.org On Thu, 2017-02-02 at 15:46 +0100, Arnd Bergmann wrote: > Putting a bare cpumask structure on the stack produces a warning on > large SMP configurations: > > drivers/thermal/cpu_cooling.c: In function 'cpufreq_state2power': > drivers/thermal/cpu_cooling.c:644:1: warning: the frame size of 1056 > bytes is larger than 1024 bytes [-Wframe-larger-than=] > drivers/thermal/cpu_cooling.c: In function > '__cpufreq_cooling_register': > drivers/thermal/cpu_cooling.c:898:1: warning: the frame size of 1104 > bytes is larger than 1024 bytes [-Wframe-larger-than=] > > The recommended workaround is to use cpumask_var_t, which behaves > just like > a normal cpu mask in most cases, but turns into a dynamic allocation > when CONFIG_CPUMASK_OFFSTACK is set. > > Signed-off-by: Arnd Bergmann > --- >  drivers/thermal/cpu_cooling.c | 39 ++++++++++++++++++++++++++------- > ------ >  1 file changed, 26 insertions(+), 13 deletions(-) > > diff --git a/drivers/thermal/cpu_cooling.c > b/drivers/thermal/cpu_cooling.c > index ca7ddaea450c..1d7f7e85f669 100644 > --- a/drivers/thermal/cpu_cooling.c > +++ b/drivers/thermal/cpu_cooling.c > @@ -609,31 +609,39 @@ static int cpufreq_state2power(struct > thermal_cooling_device *cdev, >          unsigned long state, u32 *power) >  { >   unsigned int freq, num_cpus; > - cpumask_t cpumask; > + cpumask_var_t cpumask; >   u32 static_power, dynamic_power; >   int ret; >   struct cpufreq_cooling_device *cpufreq_device = cdev- > >devdata; >   > - cpumask_and(&cpumask, &cpufreq_device->allowed_cpus, > cpu_online_mask); > - num_cpus = cpumask_weight(&cpumask); > + if (!alloc_cpumask_var(&cpumask, GFP_KERNEL)) > + return -ENOMEM; > + > + cpumask_and(cpumask, &cpufreq_device->allowed_cpus, > cpu_online_mask); > + num_cpus = cpumask_weight(cpumask); >   >   /* None of our cpus are online, so no power */ >   if (num_cpus == 0) { >   *power = 0; > - return 0; > + ret = 0; > + goto out; >   } >   >   freq = cpufreq_device->freq_table[state]; > - if (!freq) > - return -EINVAL; > + if (!freq) { > + ret = -EINVAL; > + goto out; > + } >   >   dynamic_power = cpu_freq_to_power(cpufreq_device, freq) * > num_cpus; >   ret = get_static_power(cpufreq_device, tz, freq, > &static_power); >   if (ret) > - return ret; > + goto out; >   >   *power = static_power + dynamic_power; > - return 0; > +out: > + free_cpumask_var(cpumask); > + return ret;; The patch looks good to me except that there is on redundant semicolon here. Patch applied with the typo fixed. thanks, rui >  } >   >  /** > @@ -759,16 +767,20 @@ __cpufreq_cooling_register(struct device_node > *np, >   struct cpufreq_cooling_device *cpufreq_dev; >   char dev_name[THERMAL_NAME_LENGTH]; >   struct cpufreq_frequency_table *pos, *table; > - struct cpumask temp_mask; > + cpumask_var_t temp_mask; >   unsigned int freq, i, num_cpus; >   int ret; >   struct thermal_cooling_device_ops *cooling_ops; >   > - cpumask_and(&temp_mask, clip_cpus, cpu_online_mask); > - policy = cpufreq_cpu_get(cpumask_first(&temp_mask)); > + if (!alloc_cpumask_var(&temp_mask, GFP_KERNEL)) > + return ERR_PTR(-ENOMEM); > + > + cpumask_and(temp_mask, clip_cpus, cpu_online_mask); > + policy = cpufreq_cpu_get(cpumask_first(temp_mask)); >   if (!policy) { >   pr_debug("%s: CPUFreq policy not found\n", > __func__); > - return ERR_PTR(-EPROBE_DEFER); > + cool_dev = ERR_PTR(-EPROBE_DEFER); > + goto free_cpumask; >   } >   >   table = policy->freq_table; > @@ -886,7 +898,8 @@ __cpufreq_cooling_register(struct device_node > *np, >   kfree(cpufreq_dev); >  put_policy: >   cpufreq_cpu_put(policy); > - > +free_cpumask: > + free_cpumask_var(temp_mask); >   return cool_dev; >  } >