Re: [PATCH] PM / OPP: optimize dev_pm_opp_set_rate() a bit

2016-07-25 Thread Jisheng Zhang 
On Mon, 25 Jul 2016 13:19:47 +0800 Jisheng Zhang wrote:

> Dear all,
> 
> On Fri, 22 Jul 2016 22:30:53 +0800 kbuild test robot wrote:
> 
> > Hi,
> > 
> > [auto build test WARNING on pm/linux-next]
> > [also build test WARNING on v4.7-rc7 next-20160722]
> > [if your patch is applied to the wrong git tree, please drop us a note to 
> > help improve the system]
> > 
> > url:
> > https://github.com/0day-ci/linux/commits/Jisheng-Zhang/PM-OPP-optimize-dev_pm_opp_set_rate-a-bit/20160722-205339
> > base:   https://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm.git 
> > linux-next
> > config: x86_64-allmodconfig (attached as .config)
> > compiler: gcc-6 (Debian 6.1.1-9) 6.1.1 20160705
> > reproduce:
> > # save the attached .config to linux build tree
> > make ARCH=x86_64 
> > 
> > Note: it may well be a FALSE warning. FWIW you are at least aware of it now.
> > http://gcc.gnu.org/wiki/Better_Uninitialized_Warnings
> > 
> > All warnings (new ones prefixed by >>):
> > 
> >drivers/base/power/opp/core.c: In function 'dev_pm_opp_set_rate':  
> > >> drivers/base/power/opp/core.c:666:3: warning: 'ou_volt_max' may be used 
> > >> uninitialized in this function [-Wmaybe-uninitialized]
> >   _set_opp_voltage(dev, reg, ou_volt, ou_volt_min, ou_volt_max);
> >   ^  
> > >> drivers/base/power/opp/core.c:666:3: warning: 'ou_volt_min' may be used 
> > >> uninitialized in this function [-Wmaybe-uninitialized]
> > >> drivers/base/power/opp/core.c:666:3: warning: 'ou_volt' may be used 
> > >> uninitialized in this function [-Wmaybe-uninitialized]
> 
> These warnings seem weired. We only use them when !IS_ERR(old_opp), and we
> should already set them if !IS_ERR(old_opp). Another weired thing is if
> we add something, printk e.g in _find_freq_ceil(), then these warnings 
> disappear

Hmm, it looks that gcc will inline _find_freq_ceil(), then gcc can't
detect that ou_volt* are already set. Mark _find_freq_ceil() noinline would fix
the warnings

Thanks,
Jisheng

> 
> Could you please kindly give some suggestions about how to fix these warnings?
>

Re: [PATCH] PM / OPP: optimize dev_pm_opp_set_rate() a bit

2016-07-25 Thread Jisheng Zhang 
On Mon, 25 Jul 2016 13:19:47 +0800 Jisheng Zhang wrote:

> Dear all,
> 
> On Fri, 22 Jul 2016 22:30:53 +0800 kbuild test robot wrote:
> 
> > Hi,
> > 
> > [auto build test WARNING on pm/linux-next]
> > [also build test WARNING on v4.7-rc7 next-20160722]
> > [if your patch is applied to the wrong git tree, please drop us a note to 
> > help improve the system]
> > 
> > url:
> > https://github.com/0day-ci/linux/commits/Jisheng-Zhang/PM-OPP-optimize-dev_pm_opp_set_rate-a-bit/20160722-205339
> > base:   https://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm.git 
> > linux-next
> > config: x86_64-allmodconfig (attached as .config)
> > compiler: gcc-6 (Debian 6.1.1-9) 6.1.1 20160705
> > reproduce:
> > # save the attached .config to linux build tree
> > make ARCH=x86_64 
> > 
> > Note: it may well be a FALSE warning. FWIW you are at least aware of it now.
> > http://gcc.gnu.org/wiki/Better_Uninitialized_Warnings
> > 
> > All warnings (new ones prefixed by >>):
> > 
> >drivers/base/power/opp/core.c: In function 'dev_pm_opp_set_rate':  
> > >> drivers/base/power/opp/core.c:666:3: warning: 'ou_volt_max' may be used 
> > >> uninitialized in this function [-Wmaybe-uninitialized]
> >   _set_opp_voltage(dev, reg, ou_volt, ou_volt_min, ou_volt_max);
> >   ^  
> > >> drivers/base/power/opp/core.c:666:3: warning: 'ou_volt_min' may be used 
> > >> uninitialized in this function [-Wmaybe-uninitialized]
> > >> drivers/base/power/opp/core.c:666:3: warning: 'ou_volt' may be used 
> > >> uninitialized in this function [-Wmaybe-uninitialized]
> 
> These warnings seem weired. We only use them when !IS_ERR(old_opp), and we
> should already set them if !IS_ERR(old_opp). Another weired thing is if
> we add something, printk e.g in _find_freq_ceil(), then these warnings 
> disappear

Hmm, it looks that gcc will inline _find_freq_ceil(), then gcc can't
detect that ou_volt* are already set. Mark _find_freq_ceil() noinline would fix
the warnings

Thanks,
Jisheng

> 
> Could you please kindly give some suggestions about how to fix these warnings?
>

Re: [PATCH] PM / OPP: optimize dev_pm_opp_set_rate() a bit

2016-07-24 Thread Jisheng Zhang 
Dear all,

On Fri, 22 Jul 2016 22:30:53 +0800 kbuild test robot wrote:

> Hi,
> 
> [auto build test WARNING on pm/linux-next]
> [also build test WARNING on v4.7-rc7 next-20160722]
> [if your patch is applied to the wrong git tree, please drop us a note to 
> help improve the system]
> 
> url:
> https://github.com/0day-ci/linux/commits/Jisheng-Zhang/PM-OPP-optimize-dev_pm_opp_set_rate-a-bit/20160722-205339
> base:   https://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm.git 
> linux-next
> config: x86_64-allmodconfig (attached as .config)
> compiler: gcc-6 (Debian 6.1.1-9) 6.1.1 20160705
> reproduce:
> # save the attached .config to linux build tree
> make ARCH=x86_64 
> 
> Note: it may well be a FALSE warning. FWIW you are at least aware of it now.
> http://gcc.gnu.org/wiki/Better_Uninitialized_Warnings
> 
> All warnings (new ones prefixed by >>):
> 
>drivers/base/power/opp/core.c: In function 'dev_pm_opp_set_rate':
> >> drivers/base/power/opp/core.c:666:3: warning: 'ou_volt_max' may be used 
> >> uninitialized in this function [-Wmaybe-uninitialized]  
>   _set_opp_voltage(dev, reg, ou_volt, ou_volt_min, ou_volt_max);
>   ^
> >> drivers/base/power/opp/core.c:666:3: warning: 'ou_volt_min' may be used 
> >> uninitialized in this function [-Wmaybe-uninitialized]
> >> drivers/base/power/opp/core.c:666:3: warning: 'ou_volt' may be used 
> >> uninitialized in this function [-Wmaybe-uninitialized]  

These warnings seem weired. We only use them when !IS_ERR(old_opp), and we
should already set them if !IS_ERR(old_opp). Another weired thing is if
we add something, printk e.g in _find_freq_ceil(), then these warnings disappear

Could you please kindly give some suggestions about how to fix these warnings?

Thanks,
Jisheng

> 
> vim +/ou_volt_max +666 drivers/base/power/opp/core.c
> 
> 6a0712f6 drivers/base/power/opp/core.c Viresh Kumar 2016-02-09  650   if 
> (freq < old_freq) {
> 6a0712f6 drivers/base/power/opp/core.c Viresh Kumar 2016-02-09  651   
> ret = _set_opp_voltage(dev, reg, u_volt, u_volt_min,
> 6a0712f6 drivers/base/power/opp/core.c Viresh Kumar 2016-02-09  652   
>u_volt_max);
> 6a0712f6 drivers/base/power/opp/core.c Viresh Kumar 2016-02-09  653   
> if (ret)
> 6a0712f6 drivers/base/power/opp/core.c Viresh Kumar 2016-02-09  654   
> goto restore_freq;
> 6a0712f6 drivers/base/power/opp/core.c Viresh Kumar 2016-02-09  655   }
> 6a0712f6 drivers/base/power/opp/core.c Viresh Kumar 2016-02-09  656  
> 6a0712f6 drivers/base/power/opp/core.c Viresh Kumar 2016-02-09  657   return 
> 0;
> 6a0712f6 drivers/base/power/opp/core.c Viresh Kumar 2016-02-09  658  
> 6a0712f6 drivers/base/power/opp/core.c Viresh Kumar 2016-02-09  659  
> restore_freq:
> 6a0712f6 drivers/base/power/opp/core.c Viresh Kumar 2016-02-09  660   if 
> (clk_set_rate(clk, old_freq))
> 6a0712f6 drivers/base/power/opp/core.c Viresh Kumar 2016-02-09  661   
> dev_err(dev, "%s: failed to restore old-freq (%lu Hz)\n",
> 6a0712f6 drivers/base/power/opp/core.c Viresh Kumar 2016-02-09  662   
> __func__, old_freq);
> 6a0712f6 drivers/base/power/opp/core.c Viresh Kumar 2016-02-09  663  
> restore_voltage:
> 6a0712f6 drivers/base/power/opp/core.c Viresh Kumar 2016-02-09  664   /* This 
> shouldn't harm even if the voltages weren't updated earlier */
> 6a0712f6 drivers/base/power/opp/core.c Viresh Kumar 2016-02-09  665   if 
> (!IS_ERR(old_opp))
> 6a0712f6 drivers/base/power/opp/core.c Viresh Kumar 2016-02-09 @666   
> _set_opp_voltage(dev, reg, ou_volt, ou_volt_min, ou_volt_max);
> 6a0712f6 drivers/base/power/opp/core.c Viresh Kumar 2016-02-09  667  
> 6a0712f6 drivers/base/power/opp/core.c Viresh Kumar 2016-02-09  668   return 
> ret;
> 6a0712f6 drivers/base/power/opp/core.c Viresh Kumar 2016-02-09  669  }
> 6a0712f6 drivers/base/power/opp/core.c Viresh Kumar 2016-02-09  670  
> EXPORT_SYMBOL_GPL(dev_pm_opp_set_rate);
> 6a0712f6 drivers/base/power/opp/core.c Viresh Kumar 2016-02-09  671  
> 2c2709dc drivers/base/power/opp/core.c Viresh Kumar 2016-02-16  672  /* 
> OPP-dev Helpers */
> 2c2709dc drivers/base/power/opp/core.c Viresh Kumar 2016-02-16  673  static 
> void _kfree_opp_dev_rcu(struct rcu_head *head)
> 06441658 drivers/base/power/opp.c  Viresh Kumar 2015-07-29  674  {
> 
> :: The code at line 666 was first introduced by commit
> :: 6a0712f6f199e737aa5913d28ec4bd3a25de9660 PM / OPP: Add 
> dev_pm_opp_set_rate()
> 
> :: TO: Viresh Kumar 
> :: CC: Rafael J. Wysocki 
> 
> ---
> 0-DAY kernel test infrastructureOpen Source Technology Center
> https://lists.01.org/pipermail/kbuild-all   Intel Corporation

Re: [PATCH] PM / OPP: optimize dev_pm_opp_set_rate() a bit

2016-07-24 Thread Jisheng Zhang 
Dear all,

On Fri, 22 Jul 2016 22:30:53 +0800 kbuild test robot wrote:

> Hi,
> 
> [auto build test WARNING on pm/linux-next]
> [also build test WARNING on v4.7-rc7 next-20160722]
> [if your patch is applied to the wrong git tree, please drop us a note to 
> help improve the system]
> 
> url:
> https://github.com/0day-ci/linux/commits/Jisheng-Zhang/PM-OPP-optimize-dev_pm_opp_set_rate-a-bit/20160722-205339
> base:   https://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm.git 
> linux-next
> config: x86_64-allmodconfig (attached as .config)
> compiler: gcc-6 (Debian 6.1.1-9) 6.1.1 20160705
> reproduce:
> # save the attached .config to linux build tree
> make ARCH=x86_64 
> 
> Note: it may well be a FALSE warning. FWIW you are at least aware of it now.
> http://gcc.gnu.org/wiki/Better_Uninitialized_Warnings
> 
> All warnings (new ones prefixed by >>):
> 
>drivers/base/power/opp/core.c: In function 'dev_pm_opp_set_rate':
> >> drivers/base/power/opp/core.c:666:3: warning: 'ou_volt_max' may be used 
> >> uninitialized in this function [-Wmaybe-uninitialized]  
>   _set_opp_voltage(dev, reg, ou_volt, ou_volt_min, ou_volt_max);
>   ^
> >> drivers/base/power/opp/core.c:666:3: warning: 'ou_volt_min' may be used 
> >> uninitialized in this function [-Wmaybe-uninitialized]
> >> drivers/base/power/opp/core.c:666:3: warning: 'ou_volt' may be used 
> >> uninitialized in this function [-Wmaybe-uninitialized]  

These warnings seem weired. We only use them when !IS_ERR(old_opp), and we
should already set them if !IS_ERR(old_opp). Another weired thing is if
we add something, printk e.g in _find_freq_ceil(), then these warnings disappear

Could you please kindly give some suggestions about how to fix these warnings?

Thanks,
Jisheng

> 
> vim +/ou_volt_max +666 drivers/base/power/opp/core.c
> 
> 6a0712f6 drivers/base/power/opp/core.c Viresh Kumar 2016-02-09  650   if 
> (freq < old_freq) {
> 6a0712f6 drivers/base/power/opp/core.c Viresh Kumar 2016-02-09  651   
> ret = _set_opp_voltage(dev, reg, u_volt, u_volt_min,
> 6a0712f6 drivers/base/power/opp/core.c Viresh Kumar 2016-02-09  652   
>u_volt_max);
> 6a0712f6 drivers/base/power/opp/core.c Viresh Kumar 2016-02-09  653   
> if (ret)
> 6a0712f6 drivers/base/power/opp/core.c Viresh Kumar 2016-02-09  654   
> goto restore_freq;
> 6a0712f6 drivers/base/power/opp/core.c Viresh Kumar 2016-02-09  655   }
> 6a0712f6 drivers/base/power/opp/core.c Viresh Kumar 2016-02-09  656  
> 6a0712f6 drivers/base/power/opp/core.c Viresh Kumar 2016-02-09  657   return 
> 0;
> 6a0712f6 drivers/base/power/opp/core.c Viresh Kumar 2016-02-09  658  
> 6a0712f6 drivers/base/power/opp/core.c Viresh Kumar 2016-02-09  659  
> restore_freq:
> 6a0712f6 drivers/base/power/opp/core.c Viresh Kumar 2016-02-09  660   if 
> (clk_set_rate(clk, old_freq))
> 6a0712f6 drivers/base/power/opp/core.c Viresh Kumar 2016-02-09  661   
> dev_err(dev, "%s: failed to restore old-freq (%lu Hz)\n",
> 6a0712f6 drivers/base/power/opp/core.c Viresh Kumar 2016-02-09  662   
> __func__, old_freq);
> 6a0712f6 drivers/base/power/opp/core.c Viresh Kumar 2016-02-09  663  
> restore_voltage:
> 6a0712f6 drivers/base/power/opp/core.c Viresh Kumar 2016-02-09  664   /* This 
> shouldn't harm even if the voltages weren't updated earlier */
> 6a0712f6 drivers/base/power/opp/core.c Viresh Kumar 2016-02-09  665   if 
> (!IS_ERR(old_opp))
> 6a0712f6 drivers/base/power/opp/core.c Viresh Kumar 2016-02-09 @666   
> _set_opp_voltage(dev, reg, ou_volt, ou_volt_min, ou_volt_max);
> 6a0712f6 drivers/base/power/opp/core.c Viresh Kumar 2016-02-09  667  
> 6a0712f6 drivers/base/power/opp/core.c Viresh Kumar 2016-02-09  668   return 
> ret;
> 6a0712f6 drivers/base/power/opp/core.c Viresh Kumar 2016-02-09  669  }
> 6a0712f6 drivers/base/power/opp/core.c Viresh Kumar 2016-02-09  670  
> EXPORT_SYMBOL_GPL(dev_pm_opp_set_rate);
> 6a0712f6 drivers/base/power/opp/core.c Viresh Kumar 2016-02-09  671  
> 2c2709dc drivers/base/power/opp/core.c Viresh Kumar 2016-02-16  672  /* 
> OPP-dev Helpers */
> 2c2709dc drivers/base/power/opp/core.c Viresh Kumar 2016-02-16  673  static 
> void _kfree_opp_dev_rcu(struct rcu_head *head)
> 06441658 drivers/base/power/opp.c  Viresh Kumar 2015-07-29  674  {
> 
> :: The code at line 666 was first introduced by commit
> :: 6a0712f6f199e737aa5913d28ec4bd3a25de9660 PM / OPP: Add 
> dev_pm_opp_set_rate()
> 
> :: TO: Viresh Kumar 
> :: CC: Rafael J. Wysocki 
> 
> ---
> 0-DAY kernel test infrastructureOpen Source Technology Center
> https://lists.01.org/pipermail/kbuild-all   Intel Corporation

Re: [PATCH] PM / OPP: optimize dev_pm_opp_set_rate() a bit

2016-07-24 Thread Jisheng Zhang 
Dear Viresh,

On Fri, 22 Jul 2016 09:21:51 -0700 Viresh Kumar  wrote:

> On 22-07-16, 20:42, Jisheng Zhang wrote:
> >  static int _set_opp_voltage(struct device *dev, struct regulator *reg,
> > unsigned long u_volt, unsigned long u_volt_min,
> > unsigned long u_volt_max)
> > @@ -586,9 +565,24 @@ int dev_pm_opp_set_rate(struct device *dev, unsigned 
> > long target_freq)
> > return -EINVAL;
> > }
> >  
> > -   clk = _get_opp_clk(dev);
> > -   if (IS_ERR(clk))
> > +   rcu_read_lock();
> > +
> > +   opp_table = _find_opp_table(dev);
> > +   if (IS_ERR(opp_table)) {
> > +   dev_err(dev, "%s: device opp doesn't exist\n", __func__);
> > +   rcu_read_unlock();
> > +   return PTR_ERR(opp_table);
> > +   }
> > +
> > +   clk = opp_table->clk;
> > +   if (IS_ERR(clk)) {
> > +   dev_err(dev, "%s: No clock available for the device\n",
> > +   __func__);
> > +   rcu_read_unlock();
> > return PTR_ERR(clk);
> > +   }
> > +
> > +   rcu_read_unlock();  
> 
> It is not _safe_ to use opp_table pointer after the rcu_read_unlock()

Oops, indeed. Thanks very much for pointing it out! Will fix it in v2, so
it seems we can only reduce the call of _find_opp_table to twice.

Thanks,
Jisheng

Re: [PATCH] PM / OPP: optimize dev_pm_opp_set_rate() a bit

2016-07-24 Thread Jisheng Zhang 
Dear Viresh,

On Fri, 22 Jul 2016 09:21:51 -0700 Viresh Kumar  wrote:

> On 22-07-16, 20:42, Jisheng Zhang wrote:
> >  static int _set_opp_voltage(struct device *dev, struct regulator *reg,
> > unsigned long u_volt, unsigned long u_volt_min,
> > unsigned long u_volt_max)
> > @@ -586,9 +565,24 @@ int dev_pm_opp_set_rate(struct device *dev, unsigned 
> > long target_freq)
> > return -EINVAL;
> > }
> >  
> > -   clk = _get_opp_clk(dev);
> > -   if (IS_ERR(clk))
> > +   rcu_read_lock();
> > +
> > +   opp_table = _find_opp_table(dev);
> > +   if (IS_ERR(opp_table)) {
> > +   dev_err(dev, "%s: device opp doesn't exist\n", __func__);
> > +   rcu_read_unlock();
> > +   return PTR_ERR(opp_table);
> > +   }
> > +
> > +   clk = opp_table->clk;
> > +   if (IS_ERR(clk)) {
> > +   dev_err(dev, "%s: No clock available for the device\n",
> > +   __func__);
> > +   rcu_read_unlock();
> > return PTR_ERR(clk);
> > +   }
> > +
> > +   rcu_read_unlock();  
> 
> It is not _safe_ to use opp_table pointer after the rcu_read_unlock()

Oops, indeed. Thanks very much for pointing it out! Will fix it in v2, so
it seems we can only reduce the call of _find_opp_table to twice.

Thanks,
Jisheng

Re: [PATCH] PM / OPP: optimize dev_pm_opp_set_rate() a bit

2016-07-22 Thread Viresh Kumar 
On 22-07-16, 20:42, Jisheng Zhang wrote:
>  static int _set_opp_voltage(struct device *dev, struct regulator *reg,
>   unsigned long u_volt, unsigned long u_volt_min,
>   unsigned long u_volt_max)
> @@ -586,9 +565,24 @@ int dev_pm_opp_set_rate(struct device *dev, unsigned 
> long target_freq)
>   return -EINVAL;
>   }
>  
> - clk = _get_opp_clk(dev);
> - if (IS_ERR(clk))
> + rcu_read_lock();
> +
> + opp_table = _find_opp_table(dev);
> + if (IS_ERR(opp_table)) {
> + dev_err(dev, "%s: device opp doesn't exist\n", __func__);
> + rcu_read_unlock();
> + return PTR_ERR(opp_table);
> + }
> +
> + clk = opp_table->clk;
> + if (IS_ERR(clk)) {
> + dev_err(dev, "%s: No clock available for the device\n",
> + __func__);
> + rcu_read_unlock();
>   return PTR_ERR(clk);
> + }
> +
> + rcu_read_unlock();

It is not _safe_ to use opp_table pointer after the rcu_read_unlock()
here.

-- 
viresh

Re: [PATCH] PM / OPP: optimize dev_pm_opp_set_rate() a bit

2016-07-22 Thread Viresh Kumar 
On 22-07-16, 20:42, Jisheng Zhang wrote:
>  static int _set_opp_voltage(struct device *dev, struct regulator *reg,
>   unsigned long u_volt, unsigned long u_volt_min,
>   unsigned long u_volt_max)
> @@ -586,9 +565,24 @@ int dev_pm_opp_set_rate(struct device *dev, unsigned 
> long target_freq)
>   return -EINVAL;
>   }
>  
> - clk = _get_opp_clk(dev);
> - if (IS_ERR(clk))
> + rcu_read_lock();
> +
> + opp_table = _find_opp_table(dev);
> + if (IS_ERR(opp_table)) {
> + dev_err(dev, "%s: device opp doesn't exist\n", __func__);
> + rcu_read_unlock();
> + return PTR_ERR(opp_table);
> + }
> +
> + clk = opp_table->clk;
> + if (IS_ERR(clk)) {
> + dev_err(dev, "%s: No clock available for the device\n",
> + __func__);
> + rcu_read_unlock();
>   return PTR_ERR(clk);
> + }
> +
> + rcu_read_unlock();

It is not _safe_ to use opp_table pointer after the rcu_read_unlock()
here.

-- 
viresh

Re: [PATCH] PM / OPP: optimize dev_pm_opp_set_rate() a bit

2016-07-22 Thread kbuild test robot 
Hi,

[auto build test WARNING on pm/linux-next]
[also build test WARNING on v4.7-rc7 next-20160722]
[if your patch is applied to the wrong git tree, please drop us a note to help 
improve the system]

url:
https://github.com/0day-ci/linux/commits/Jisheng-Zhang/PM-OPP-optimize-dev_pm_opp_set_rate-a-bit/20160722-205339
base:   https://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm.git 
linux-next
config: x86_64-allmodconfig (attached as .config)
compiler: gcc-6 (Debian 6.1.1-9) 6.1.1 20160705
reproduce:
# save the attached .config to linux build tree
make ARCH=x86_64 

Note: it may well be a FALSE warning. FWIW you are at least aware of it now.
http://gcc.gnu.org/wiki/Better_Uninitialized_Warnings

All warnings (new ones prefixed by >>):

   drivers/base/power/opp/core.c: In function 'dev_pm_opp_set_rate':
>> drivers/base/power/opp/core.c:666:3: warning: 'ou_volt_max' may be used 
>> uninitialized in this function [-Wmaybe-uninitialized]
  _set_opp_voltage(dev, reg, ou_volt, ou_volt_min, ou_volt_max);
  ^
>> drivers/base/power/opp/core.c:666:3: warning: 'ou_volt_min' may be used 
>> uninitialized in this function [-Wmaybe-uninitialized]
>> drivers/base/power/opp/core.c:666:3: warning: 'ou_volt' may be used 
>> uninitialized in this function [-Wmaybe-uninitialized]

vim +/ou_volt_max +666 drivers/base/power/opp/core.c

6a0712f6 drivers/base/power/opp/core.c Viresh Kumar 2016-02-09  650 if 
(freq < old_freq) {
6a0712f6 drivers/base/power/opp/core.c Viresh Kumar 2016-02-09  651 
ret = _set_opp_voltage(dev, reg, u_volt, u_volt_min,
6a0712f6 drivers/base/power/opp/core.c Viresh Kumar 2016-02-09  652 
   u_volt_max);
6a0712f6 drivers/base/power/opp/core.c Viresh Kumar 2016-02-09  653 
if (ret)
6a0712f6 drivers/base/power/opp/core.c Viresh Kumar 2016-02-09  654 
goto restore_freq;
6a0712f6 drivers/base/power/opp/core.c Viresh Kumar 2016-02-09  655 }
6a0712f6 drivers/base/power/opp/core.c Viresh Kumar 2016-02-09  656  
6a0712f6 drivers/base/power/opp/core.c Viresh Kumar 2016-02-09  657 return 
0;
6a0712f6 drivers/base/power/opp/core.c Viresh Kumar 2016-02-09  658  
6a0712f6 drivers/base/power/opp/core.c Viresh Kumar 2016-02-09  659  
restore_freq:
6a0712f6 drivers/base/power/opp/core.c Viresh Kumar 2016-02-09  660 if 
(clk_set_rate(clk, old_freq))
6a0712f6 drivers/base/power/opp/core.c Viresh Kumar 2016-02-09  661 
dev_err(dev, "%s: failed to restore old-freq (%lu Hz)\n",
6a0712f6 drivers/base/power/opp/core.c Viresh Kumar 2016-02-09  662 
__func__, old_freq);
6a0712f6 drivers/base/power/opp/core.c Viresh Kumar 2016-02-09  663  
restore_voltage:
6a0712f6 drivers/base/power/opp/core.c Viresh Kumar 2016-02-09  664 /* This 
shouldn't harm even if the voltages weren't updated earlier */
6a0712f6 drivers/base/power/opp/core.c Viresh Kumar 2016-02-09  665 if 
(!IS_ERR(old_opp))
6a0712f6 drivers/base/power/opp/core.c Viresh Kumar 2016-02-09 @666 
_set_opp_voltage(dev, reg, ou_volt, ou_volt_min, ou_volt_max);
6a0712f6 drivers/base/power/opp/core.c Viresh Kumar 2016-02-09  667  
6a0712f6 drivers/base/power/opp/core.c Viresh Kumar 2016-02-09  668 return 
ret;
6a0712f6 drivers/base/power/opp/core.c Viresh Kumar 2016-02-09  669  }
6a0712f6 drivers/base/power/opp/core.c Viresh Kumar 2016-02-09  670  
EXPORT_SYMBOL_GPL(dev_pm_opp_set_rate);
6a0712f6 drivers/base/power/opp/core.c Viresh Kumar 2016-02-09  671  
2c2709dc drivers/base/power/opp/core.c Viresh Kumar 2016-02-16  672  /* OPP-dev 
Helpers */
2c2709dc drivers/base/power/opp/core.c Viresh Kumar 2016-02-16  673  static 
void _kfree_opp_dev_rcu(struct rcu_head *head)
06441658 drivers/base/power/opp.c  Viresh Kumar 2015-07-29  674  {

:: The code at line 666 was first introduced by commit
:: 6a0712f6f199e737aa5913d28ec4bd3a25de9660 PM / OPP: Add 
dev_pm_opp_set_rate()

:: TO: Viresh Kumar 
:: CC: Rafael J. Wysocki 

---
0-DAY kernel test infrastructureOpen Source Technology Center
https://lists.01.org/pipermail/kbuild-all   Intel Corporation


.config.gz
Description: Binary data

Re: [PATCH] PM / OPP: optimize dev_pm_opp_set_rate() a bit

2016-07-22 Thread kbuild test robot 
Hi,

[auto build test WARNING on pm/linux-next]
[also build test WARNING on v4.7-rc7 next-20160722]
[if your patch is applied to the wrong git tree, please drop us a note to help 
improve the system]

url:
https://github.com/0day-ci/linux/commits/Jisheng-Zhang/PM-OPP-optimize-dev_pm_opp_set_rate-a-bit/20160722-205339
base:   https://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm.git 
linux-next
config: x86_64-allmodconfig (attached as .config)
compiler: gcc-6 (Debian 6.1.1-9) 6.1.1 20160705
reproduce:
# save the attached .config to linux build tree
make ARCH=x86_64 

Note: it may well be a FALSE warning. FWIW you are at least aware of it now.
http://gcc.gnu.org/wiki/Better_Uninitialized_Warnings

All warnings (new ones prefixed by >>):

   drivers/base/power/opp/core.c: In function 'dev_pm_opp_set_rate':
>> drivers/base/power/opp/core.c:666:3: warning: 'ou_volt_max' may be used 
>> uninitialized in this function [-Wmaybe-uninitialized]
  _set_opp_voltage(dev, reg, ou_volt, ou_volt_min, ou_volt_max);
  ^
>> drivers/base/power/opp/core.c:666:3: warning: 'ou_volt_min' may be used 
>> uninitialized in this function [-Wmaybe-uninitialized]
>> drivers/base/power/opp/core.c:666:3: warning: 'ou_volt' may be used 
>> uninitialized in this function [-Wmaybe-uninitialized]

vim +/ou_volt_max +666 drivers/base/power/opp/core.c

6a0712f6 drivers/base/power/opp/core.c Viresh Kumar 2016-02-09  650 if 
(freq < old_freq) {
6a0712f6 drivers/base/power/opp/core.c Viresh Kumar 2016-02-09  651 
ret = _set_opp_voltage(dev, reg, u_volt, u_volt_min,
6a0712f6 drivers/base/power/opp/core.c Viresh Kumar 2016-02-09  652 
   u_volt_max);
6a0712f6 drivers/base/power/opp/core.c Viresh Kumar 2016-02-09  653 
if (ret)
6a0712f6 drivers/base/power/opp/core.c Viresh Kumar 2016-02-09  654 
goto restore_freq;
6a0712f6 drivers/base/power/opp/core.c Viresh Kumar 2016-02-09  655 }
6a0712f6 drivers/base/power/opp/core.c Viresh Kumar 2016-02-09  656  
6a0712f6 drivers/base/power/opp/core.c Viresh Kumar 2016-02-09  657 return 
0;
6a0712f6 drivers/base/power/opp/core.c Viresh Kumar 2016-02-09  658  
6a0712f6 drivers/base/power/opp/core.c Viresh Kumar 2016-02-09  659  
restore_freq:
6a0712f6 drivers/base/power/opp/core.c Viresh Kumar 2016-02-09  660 if 
(clk_set_rate(clk, old_freq))
6a0712f6 drivers/base/power/opp/core.c Viresh Kumar 2016-02-09  661 
dev_err(dev, "%s: failed to restore old-freq (%lu Hz)\n",
6a0712f6 drivers/base/power/opp/core.c Viresh Kumar 2016-02-09  662 
__func__, old_freq);
6a0712f6 drivers/base/power/opp/core.c Viresh Kumar 2016-02-09  663  
restore_voltage:
6a0712f6 drivers/base/power/opp/core.c Viresh Kumar 2016-02-09  664 /* This 
shouldn't harm even if the voltages weren't updated earlier */
6a0712f6 drivers/base/power/opp/core.c Viresh Kumar 2016-02-09  665 if 
(!IS_ERR(old_opp))
6a0712f6 drivers/base/power/opp/core.c Viresh Kumar 2016-02-09 @666 
_set_opp_voltage(dev, reg, ou_volt, ou_volt_min, ou_volt_max);
6a0712f6 drivers/base/power/opp/core.c Viresh Kumar 2016-02-09  667  
6a0712f6 drivers/base/power/opp/core.c Viresh Kumar 2016-02-09  668 return 
ret;
6a0712f6 drivers/base/power/opp/core.c Viresh Kumar 2016-02-09  669  }
6a0712f6 drivers/base/power/opp/core.c Viresh Kumar 2016-02-09  670  
EXPORT_SYMBOL_GPL(dev_pm_opp_set_rate);
6a0712f6 drivers/base/power/opp/core.c Viresh Kumar 2016-02-09  671  
2c2709dc drivers/base/power/opp/core.c Viresh Kumar 2016-02-16  672  /* OPP-dev 
Helpers */
2c2709dc drivers/base/power/opp/core.c Viresh Kumar 2016-02-16  673  static 
void _kfree_opp_dev_rcu(struct rcu_head *head)
06441658 drivers/base/power/opp.c  Viresh Kumar 2015-07-29  674  {

:: The code at line 666 was first introduced by commit
:: 6a0712f6f199e737aa5913d28ec4bd3a25de9660 PM / OPP: Add 
dev_pm_opp_set_rate()

:: TO: Viresh Kumar 
:: CC: Rafael J. Wysocki 

---
0-DAY kernel test infrastructureOpen Source Technology Center
https://lists.01.org/pipermail/kbuild-all   Intel Corporation


.config.gz
Description: Binary data

[PATCH] PM / OPP: optimize dev_pm_opp_set_rate() a bit

2016-07-22 Thread Jisheng Zhang 
In dev_pm_opp_set_rate(), _find_opp_table() is called three times: once
by _get_opp_clk(), twice by dev_pm_opp_find_freq_ceil(). If there are
several opp_tables in the system, three times of opp table finding is a
big waste. This patch reduced the call of _find_opp_table() to only
once.

Signed-off-by: Jisheng Zhang 
---
 drivers/base/power/opp/core.c | 85 ++-
 1 file changed, 36 insertions(+), 49 deletions(-)

diff --git a/drivers/base/power/opp/core.c b/drivers/base/power/opp/core.c
index 7c04c87..96043ee 100644
--- a/drivers/base/power/opp/core.c
+++ b/drivers/base/power/opp/core.c
@@ -402,6 +402,22 @@ struct dev_pm_opp *dev_pm_opp_find_freq_exact(struct 
device *dev,
 }
 EXPORT_SYMBOL_GPL(dev_pm_opp_find_freq_exact);
 
+static struct dev_pm_opp *_find_freq_ceil(struct opp_table *opp_table,
+ unsigned long *freq)
+{
+   struct dev_pm_opp *temp_opp, *opp = ERR_PTR(-ERANGE);
+
+   list_for_each_entry_rcu(temp_opp, _table->opp_list, node) {
+   if (temp_opp->available && temp_opp->rate >= *freq) {
+   opp = temp_opp;
+   *freq = opp->rate;
+   break;
+   }
+   }
+
+   return opp;
+}
+
 /**
  * dev_pm_opp_find_freq_ceil() - Search for an rounded ceil freq
  * @dev:   device for which we do this operation
@@ -427,7 +443,6 @@ struct dev_pm_opp *dev_pm_opp_find_freq_ceil(struct device 
*dev,
 unsigned long *freq)
 {
struct opp_table *opp_table;
-   struct dev_pm_opp *temp_opp, *opp = ERR_PTR(-ERANGE);
 
opp_rcu_lockdep_assert();
 
@@ -440,15 +455,7 @@ struct dev_pm_opp *dev_pm_opp_find_freq_ceil(struct device 
*dev,
if (IS_ERR(opp_table))
return ERR_CAST(opp_table);
 
-   list_for_each_entry_rcu(temp_opp, _table->opp_list, node) {
-   if (temp_opp->available && temp_opp->rate >= *freq) {
-   opp = temp_opp;
-   *freq = opp->rate;
-   break;
-   }
-   }
-
-   return opp;
+   return _find_freq_ceil(opp_table, freq);
 }
 EXPORT_SYMBOL_GPL(dev_pm_opp_find_freq_ceil);
 
@@ -506,34 +513,6 @@ struct dev_pm_opp *dev_pm_opp_find_freq_floor(struct 
device *dev,
 }
 EXPORT_SYMBOL_GPL(dev_pm_opp_find_freq_floor);
 
-/*
- * The caller needs to ensure that opp_table (and hence the clk) isn't freed,
- * while clk returned here is used.
- */
-static struct clk *_get_opp_clk(struct device *dev)
-{
-   struct opp_table *opp_table;
-   struct clk *clk;
-
-   rcu_read_lock();
-
-   opp_table = _find_opp_table(dev);
-   if (IS_ERR(opp_table)) {
-   dev_err(dev, "%s: device opp doesn't exist\n", __func__);
-   clk = ERR_CAST(opp_table);
-   goto unlock;
-   }
-
-   clk = opp_table->clk;
-   if (IS_ERR(clk))
-   dev_err(dev, "%s: No clock available for the device\n",
-   __func__);
-
-unlock:
-   rcu_read_unlock();
-   return clk;
-}
-
 static int _set_opp_voltage(struct device *dev, struct regulator *reg,
unsigned long u_volt, unsigned long u_volt_min,
unsigned long u_volt_max)
@@ -586,9 +565,24 @@ int dev_pm_opp_set_rate(struct device *dev, unsigned long 
target_freq)
return -EINVAL;
}
 
-   clk = _get_opp_clk(dev);
-   if (IS_ERR(clk))
+   rcu_read_lock();
+
+   opp_table = _find_opp_table(dev);
+   if (IS_ERR(opp_table)) {
+   dev_err(dev, "%s: device opp doesn't exist\n", __func__);
+   rcu_read_unlock();
+   return PTR_ERR(opp_table);
+   }
+
+   clk = opp_table->clk;
+   if (IS_ERR(clk)) {
+   dev_err(dev, "%s: No clock available for the device\n",
+   __func__);
+   rcu_read_unlock();
return PTR_ERR(clk);
+   }
+
+   rcu_read_unlock();
 
freq = clk_round_rate(clk, target_freq);
if ((long)freq <= 0)
@@ -605,14 +599,7 @@ int dev_pm_opp_set_rate(struct device *dev, unsigned long 
target_freq)
 
rcu_read_lock();
 
-   opp_table = _find_opp_table(dev);
-   if (IS_ERR(opp_table)) {
-   dev_err(dev, "%s: device opp doesn't exist\n", __func__);
-   rcu_read_unlock();
-   return PTR_ERR(opp_table);
-   }
-
-   old_opp = dev_pm_opp_find_freq_ceil(dev, _freq);
+   old_opp = _find_freq_ceil(opp_table, _freq);
if (!IS_ERR(old_opp)) {
ou_volt = old_opp->u_volt;
ou_volt_min = old_opp->u_volt_min;
@@ -622,7 +609,7 @@ int dev_pm_opp_set_rate(struct device *dev, unsigned long 
target_freq)
__func__, old_freq, PTR_ERR(old_opp));
}
 
-   opp = dev_pm_opp_find_freq_ceil(dev, );
+

[PATCH] PM / OPP: optimize dev_pm_opp_set_rate() a bit

2016-07-22 Thread Jisheng Zhang 
In dev_pm_opp_set_rate(), _find_opp_table() is called three times: once
by _get_opp_clk(), twice by dev_pm_opp_find_freq_ceil(). If there are
several opp_tables in the system, three times of opp table finding is a
big waste. This patch reduced the call of _find_opp_table() to only
once.

Signed-off-by: Jisheng Zhang 
---
 drivers/base/power/opp/core.c | 85 ++-
 1 file changed, 36 insertions(+), 49 deletions(-)

diff --git a/drivers/base/power/opp/core.c b/drivers/base/power/opp/core.c
index 7c04c87..96043ee 100644
--- a/drivers/base/power/opp/core.c
+++ b/drivers/base/power/opp/core.c
@@ -402,6 +402,22 @@ struct dev_pm_opp *dev_pm_opp_find_freq_exact(struct 
device *dev,
 }
 EXPORT_SYMBOL_GPL(dev_pm_opp_find_freq_exact);
 
+static struct dev_pm_opp *_find_freq_ceil(struct opp_table *opp_table,
+ unsigned long *freq)
+{
+   struct dev_pm_opp *temp_opp, *opp = ERR_PTR(-ERANGE);
+
+   list_for_each_entry_rcu(temp_opp, _table->opp_list, node) {
+   if (temp_opp->available && temp_opp->rate >= *freq) {
+   opp = temp_opp;
+   *freq = opp->rate;
+   break;
+   }
+   }
+
+   return opp;
+}
+
 /**
  * dev_pm_opp_find_freq_ceil() - Search for an rounded ceil freq
  * @dev:   device for which we do this operation
@@ -427,7 +443,6 @@ struct dev_pm_opp *dev_pm_opp_find_freq_ceil(struct device 
*dev,
 unsigned long *freq)
 {
struct opp_table *opp_table;
-   struct dev_pm_opp *temp_opp, *opp = ERR_PTR(-ERANGE);
 
opp_rcu_lockdep_assert();
 
@@ -440,15 +455,7 @@ struct dev_pm_opp *dev_pm_opp_find_freq_ceil(struct device 
*dev,
if (IS_ERR(opp_table))
return ERR_CAST(opp_table);
 
-   list_for_each_entry_rcu(temp_opp, _table->opp_list, node) {
-   if (temp_opp->available && temp_opp->rate >= *freq) {
-   opp = temp_opp;
-   *freq = opp->rate;
-   break;
-   }
-   }
-
-   return opp;
+   return _find_freq_ceil(opp_table, freq);
 }
 EXPORT_SYMBOL_GPL(dev_pm_opp_find_freq_ceil);
 
@@ -506,34 +513,6 @@ struct dev_pm_opp *dev_pm_opp_find_freq_floor(struct 
device *dev,
 }
 EXPORT_SYMBOL_GPL(dev_pm_opp_find_freq_floor);
 
-/*
- * The caller needs to ensure that opp_table (and hence the clk) isn't freed,
- * while clk returned here is used.
- */
-static struct clk *_get_opp_clk(struct device *dev)
-{
-   struct opp_table *opp_table;
-   struct clk *clk;
-
-   rcu_read_lock();
-
-   opp_table = _find_opp_table(dev);
-   if (IS_ERR(opp_table)) {
-   dev_err(dev, "%s: device opp doesn't exist\n", __func__);
-   clk = ERR_CAST(opp_table);
-   goto unlock;
-   }
-
-   clk = opp_table->clk;
-   if (IS_ERR(clk))
-   dev_err(dev, "%s: No clock available for the device\n",
-   __func__);
-
-unlock:
-   rcu_read_unlock();
-   return clk;
-}
-
 static int _set_opp_voltage(struct device *dev, struct regulator *reg,
unsigned long u_volt, unsigned long u_volt_min,
unsigned long u_volt_max)
@@ -586,9 +565,24 @@ int dev_pm_opp_set_rate(struct device *dev, unsigned long 
target_freq)
return -EINVAL;
}
 
-   clk = _get_opp_clk(dev);
-   if (IS_ERR(clk))
+   rcu_read_lock();
+
+   opp_table = _find_opp_table(dev);
+   if (IS_ERR(opp_table)) {
+   dev_err(dev, "%s: device opp doesn't exist\n", __func__);
+   rcu_read_unlock();
+   return PTR_ERR(opp_table);
+   }
+
+   clk = opp_table->clk;
+   if (IS_ERR(clk)) {
+   dev_err(dev, "%s: No clock available for the device\n",
+   __func__);
+   rcu_read_unlock();
return PTR_ERR(clk);
+   }
+
+   rcu_read_unlock();
 
freq = clk_round_rate(clk, target_freq);
if ((long)freq <= 0)
@@ -605,14 +599,7 @@ int dev_pm_opp_set_rate(struct device *dev, unsigned long 
target_freq)
 
rcu_read_lock();
 
-   opp_table = _find_opp_table(dev);
-   if (IS_ERR(opp_table)) {
-   dev_err(dev, "%s: device opp doesn't exist\n", __func__);
-   rcu_read_unlock();
-   return PTR_ERR(opp_table);
-   }
-
-   old_opp = dev_pm_opp_find_freq_ceil(dev, _freq);
+   old_opp = _find_freq_ceil(opp_table, _freq);
if (!IS_ERR(old_opp)) {
ou_volt = old_opp->u_volt;
ou_volt_min = old_opp->u_volt_min;
@@ -622,7 +609,7 @@ int dev_pm_opp_set_rate(struct device *dev, unsigned long 
target_freq)
__func__, old_freq, PTR_ERR(old_opp));
}
 
-   opp = dev_pm_opp_find_freq_ceil(dev, );
+   opp =