[patch 1/3] intel_idle: fix API misuse

[patch 1/3] intel_idle: fix API misuse

[akpm]

From: Shaohua Li <shaohua.li@intel.com>
Subject: intel_idle: fix API misuse

smp_call_function() only lets all other CPUs execute a specific function,
while we expect all CPUs do in intel_idle.  Without the fix, we could have
one cpu which has auto_demotion enabled or has no boradcast timer setup. 
Usually we don't see impact because auto demotion just harms power and the
intel_idle init is called in CPU 0, where boradcast timer delivers
interrupt, but this still could be a problem.

Signed-off-by: Shaohua Li <shaohua.li@intel.com>
Cc: Len Brown <lenb@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 drivers/idle/intel_idle.c |    6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff -puN drivers/idle/intel_idle.c~intel_idle-fix-api-misuse drivers/idle/intel_idle.c
--- a/drivers/idle/intel_idle.c~intel_idle-fix-api-misuse
+++ a/drivers/idle/intel_idle.c
@@ -394,7 +394,7 @@ static int intel_idle_probe(void)
 	if (boot_cpu_has(X86_FEATURE_ARAT))	/* Always Reliable APIC Timer */
 		lapic_timer_reliable_states = LAPIC_TIMER_ALWAYS_RELIABLE;
 	else {
-		smp_call_function(__setup_broadcast_timer, (void *)true, 1);
+		on_each_cpu(__setup_broadcast_timer, (void *)true, 1);
 		register_cpu_notifier(&setup_broadcast_notifier);
 	}
 
@@ -471,7 +471,7 @@ static int intel_idle_cpuidle_driver_ini
 	}
 
 	if (auto_demotion_disable_flags)
-		smp_call_function(auto_demotion_disable, NULL, 1);
+		on_each_cpu(auto_demotion_disable, NULL, 1);
 
 	return 0;
 }
@@ -568,7 +568,7 @@ static void __exit intel_idle_exit(void)
 	cpuidle_unregister_driver(&intel_idle_driver);
 
 	if (lapic_timer_reliable_states != LAPIC_TIMER_ALWAYS_RELIABLE) {
-		smp_call_function(__setup_broadcast_timer, (void *)false, 1);
+		on_each_cpu(__setup_broadcast_timer, (void *)false, 1);
 		unregister_cpu_notifier(&setup_broadcast_notifier);
 	}
 
_

Re: [patch 1/3] intel_idle: fix API misuse

[Thomas Renninger]

On Wednesday, January 11, 2012 12:48:19 AM akpm@linux-foundation.org wrote:
> From: Shaohua Li <shaohua.li@intel.com>
> Subject: intel_idle: fix API misuse

This one looks worth adding:
CC: stable@vger.kernel.org

 
> smp_call_function() only lets all other CPUs execute a specific function,
> while we expect all CPUs do in intel_idle.  Without the fix, we could have
> one cpu which has auto_demotion enabled or has no boradcast timer setup. 
> Usually we don't see impact because auto demotion just harms power and the
> intel_idle init is called in CPU 0, where boradcast timer delivers
> interrupt, but this still could be a problem.
> 
> Signed-off-by: Shaohua Li <shaohua.li@intel.com>
> Cc: Len Brown <lenb@kernel.org>
> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
CC: stable@vger.kernel.org

   Thomas

Re: [patch 1/3] intel_idle: fix API misuse

[Andrew Morton]

(let's cc stable on this thread then!)

On Tue, 17 Jan 2012 11:37:58 +0100
Thomas Renninger <trenn@suse.de> wrote:

> On Wednesday, January 11, 2012 12:48:19 AM akpm@linux-foundation.org wrote:
> > From: Shaohua Li <shaohua.li@intel.com>
> > Subject: intel_idle: fix API misuse
> 
> This one looks worth adding:
> CC: stable@vger.kernel.org
> 
>  
> > smp_call_function() only lets all other CPUs execute a specific function,
> > while we expect all CPUs do in intel_idle.  Without the fix, we could have
> > one cpu which has auto_demotion enabled or has no boradcast timer setup. 
> > Usually we don't see impact because auto demotion just harms power and the
> > intel_idle init is called in CPU 0, where boradcast timer delivers
> > interrupt, but this still could be a problem.
> > 
> > Signed-off-by: Shaohua Li <shaohua.li@intel.com>
> > Cc: Len Brown <lenb@kernel.org>
> > Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
> CC: stable@vger.kernel.org
> 

OK.  I think Len is processing these patches at present.  So
stable@vger.kernel.org will see when I've dropped my copy of the patch,
but the version which goes into mainline might be missing the stable
tag.  Hopefully Greg is awake enough to sort out that cryptic messaging!

Re: [patch 1/3] intel_idle: fix API misuse

[Greg KH]

On Tue, Jan 17, 2012 at 04:21:43PM -0800, Andrew Morton wrote:
> (let's cc stable on this thread then!)
> 
> On Tue, 17 Jan 2012 11:37:58 +0100
> Thomas Renninger <trenn@suse.de> wrote:
> 
> > On Wednesday, January 11, 2012 12:48:19 AM akpm@linux-foundation.org wrote:
> > > From: Shaohua Li <shaohua.li@intel.com>
> > > Subject: intel_idle: fix API misuse
> > 
> > This one looks worth adding:
> > CC: stable@vger.kernel.org
> > 
> >  
> > > smp_call_function() only lets all other CPUs execute a specific function,
> > > while we expect all CPUs do in intel_idle.  Without the fix, we could have
> > > one cpu which has auto_demotion enabled or has no boradcast timer setup. 
> > > Usually we don't see impact because auto demotion just harms power and the
> > > intel_idle init is called in CPU 0, where boradcast timer delivers
> > > interrupt, but this still could be a problem.
> > > 
> > > Signed-off-by: Shaohua Li <shaohua.li@intel.com>
> > > Cc: Len Brown <lenb@kernel.org>
> > > Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
> > CC: stable@vger.kernel.org
> > 
> 
> OK.  I think Len is processing these patches at present.  So
> stable@vger.kernel.org will see when I've dropped my copy of the patch,
> but the version which goes into mainline might be missing the stable
> tag.  Hopefully Greg is awake enough to sort out that cryptic messaging!

In case I'm not, can someone send me the git commit ids that you want
added to the stable trees to stable@vger.kernel.org when they hit
Linus's tree?

thanks,

greg k-h