[ 092/101] cpufreq / powernow-k8: Remove usage of smp_processor_id() in preemptible code
3.6-stable review patch. If anyone has any objections, please let me know.
--
From: Andreas Herrmann
commit e4df1cbcc1f329e53a1fff7450b2229e0addff20 upstream.
Commit 6889125b8b4e09c5e53e6ecab3433bed1ce198c9
(cpufreq/powernow-k8: workqueue user shouldn't migrate the kworker to another
CPU)
causes powernow-k8 to trigger a preempt warning, e.g.:
BUG: using smp_processor_id() in preemptible [] code: cpufreq/3776
caller is powernowk8_target+0x20/0x49
Pid: 3776, comm: cpufreq Not tainted 3.6.0 #9
Call Trace:
[] debug_smp_processor_id+0xc7/0xe0
[] powernowk8_target+0x20/0x49
[] __cpufreq_driver_target+0x82/0x8a
[] cpufreq_governor_performance+0x4e/0x54
[] __cpufreq_governor+0x8c/0xc9
[] __cpufreq_set_policy+0x1a9/0x21e
[] store_scaling_governor+0x16f/0x19b
[] ? cpufreq_update_policy+0x124/0x124
[] ? _raw_spin_unlock_irqrestore+0x2c/0x49
[] store+0x60/0x88
[] sysfs_write_file+0xf4/0x130
[] vfs_write+0xb5/0x151
[] sys_write+0x4a/0x71
[] system_call_fastpath+0x16/0x1b
Fix this by by always using work_on_cpu().
Signed-off-by: Andreas Herrmann
Signed-off-by: Rafael J. Wysocki
Signed-off-by: Greg Kroah-Hartman
---
drivers/cpufreq/powernow-k8.c |9 +
1 file changed, 1 insertion(+), 8 deletions(-)
--- a/drivers/cpufreq/powernow-k8.c
+++ b/drivers/cpufreq/powernow-k8.c
@@ -1223,14 +1223,7 @@ static int powernowk8_target(struct cpuf
struct powernowk8_target_arg pta = { .pol = pol, .targfreq = targfreq,
.relation = relation };
- /*
-* Must run on @pol->cpu. cpufreq core is responsible for ensuring
-* that we're bound to the current CPU and pol->cpu stays online.
-*/
- if (smp_processor_id() == pol->cpu)
- return powernowk8_target_fn();
- else
- return work_on_cpu(pol->cpu, powernowk8_target_fn, );
+ return work_on_cpu(pol->cpu, powernowk8_target_fn, );
}
/* Driver entry point to verify the policy and range of frequencies */
--
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[ 092/101] cpufreq / powernow-k8: Remove usage of smp_processor_id() in preemptible code
3.6-stable review patch. If anyone has any objections, please let me know.
--
From: Andreas Herrmann andreas.herrma...@amd.com
commit e4df1cbcc1f329e53a1fff7450b2229e0addff20 upstream.
Commit 6889125b8b4e09c5e53e6ecab3433bed1ce198c9
(cpufreq/powernow-k8: workqueue user shouldn't migrate the kworker to another
CPU)
causes powernow-k8 to trigger a preempt warning, e.g.:
BUG: using smp_processor_id() in preemptible [] code: cpufreq/3776
caller is powernowk8_target+0x20/0x49
Pid: 3776, comm: cpufreq Not tainted 3.6.0 #9
Call Trace:
[8125b447] debug_smp_processor_id+0xc7/0xe0
[814877e7] powernowk8_target+0x20/0x49
[81482b02] __cpufreq_driver_target+0x82/0x8a
[81484fc6] cpufreq_governor_performance+0x4e/0x54
[81482c50] __cpufreq_governor+0x8c/0xc9
[81482e6f] __cpufreq_set_policy+0x1a9/0x21e
[814839af] store_scaling_governor+0x16f/0x19b
[81484f16] ? cpufreq_update_policy+0x124/0x124
[8162b4a5] ? _raw_spin_unlock_irqrestore+0x2c/0x49
[81483640] store+0x60/0x88
[811708c0] sysfs_write_file+0xf4/0x130
[8111243b] vfs_write+0xb5/0x151
[811126e0] sys_write+0x4a/0x71
[816319a9] system_call_fastpath+0x16/0x1b
Fix this by by always using work_on_cpu().
Signed-off-by: Andreas Herrmann andreas.herrma...@amd.com
Signed-off-by: Rafael J. Wysocki rafael.j.wyso...@intel.com
Signed-off-by: Greg Kroah-Hartman gre...@linuxfoundation.org
---
drivers/cpufreq/powernow-k8.c |9 +
1 file changed, 1 insertion(+), 8 deletions(-)
--- a/drivers/cpufreq/powernow-k8.c
+++ b/drivers/cpufreq/powernow-k8.c
@@ -1223,14 +1223,7 @@ static int powernowk8_target(struct cpuf
struct powernowk8_target_arg pta = { .pol = pol, .targfreq = targfreq,
.relation = relation };
- /*
-* Must run on @pol-cpu. cpufreq core is responsible for ensuring
-* that we're bound to the current CPU and pol-cpu stays online.
-*/
- if (smp_processor_id() == pol-cpu)
- return powernowk8_target_fn(pta);
- else
- return work_on_cpu(pol-cpu, powernowk8_target_fn, pta);
+ return work_on_cpu(pol-cpu, powernowk8_target_fn, pta);
}
/* Driver entry point to verify the policy and range of frequencies */
--
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