From e4df1cbcc1f329e53a1fff7450b2229e0addff20 Mon Sep 17 00:00:00 2001 From: Andreas Herrmann Date: Tue, 23 Oct 2012 00:55:10 +0200 Subject: [PATCH] cpufreq / powernow-k8: Remove usage of smp_processor_id() in preemptible code 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 [00000000] 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 Cc: stable@vger.kernel.org Signed-off-by: Rafael J. Wysocki --- drivers/cpufreq/powernow-k8.c | 9 +-------- 1 file changed, 1 insertion(+), 8 deletions(-) diff --git a/drivers/cpufreq/powernow-k8.c b/drivers/cpufreq/powernow-k8.c index 129e80bfff22..c16a3a593ba4 100644 --- a/drivers/cpufreq/powernow-k8.c +++ b/drivers/cpufreq/powernow-k8.c @@ -1052,14 +1052,7 @@ static int powernowk8_target(struct cpufreq_policy *pol, 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 */