From 8ff69732d484ea9ccbf242cc49b4fe9538e64c71 Mon Sep 17 00:00:00 2001 From: Dave Jones Date: Sun, 5 Mar 2006 03:37:23 -0500 Subject: [PATCH] [CPUFREQ] Fix handling for CPU hotplug This patch adds proper logic to cpufreq driver in order to handle CPU Hotplug. When CPUs go on/offline, the affected CPUs data, cpufreq_policy->cpus, is not updated properly. This causes sysfs directories and symlinks to be in an incorrect state after few CPU on/offlines. Signed-off-by: Jacob Shin Signed-off-by: Dave Jones --- drivers/cpufreq/cpufreq.c | 51 +++++++++++++++++++++++++++++++++++++-- 1 file changed, 49 insertions(+), 2 deletions(-) diff --git a/drivers/cpufreq/cpufreq.c b/drivers/cpufreq/cpufreq.c index cb7d6e0db7..aed80e6aec 100644 --- a/drivers/cpufreq/cpufreq.c +++ b/drivers/cpufreq/cpufreq.c @@ -6,6 +6,8 @@ * * Oct 2005 - Ashok Raj * Added handling for CPU hotplug + * Feb 2006 - Jacob Shin + * Fix handling for CPU hotplug -- affected CPUs * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License version 2 as @@ -573,8 +575,12 @@ static int cpufreq_add_dev (struct sys_device * sys_dev) struct cpufreq_policy new_policy; struct cpufreq_policy *policy; struct freq_attr **drv_attr; + struct sys_device *cpu_sys_dev; unsigned long flags; unsigned int j; +#ifdef CONFIG_SMP + struct cpufreq_policy *managed_policy; +#endif if (cpu_is_offline(cpu)) return 0; @@ -587,8 +593,7 @@ static int cpufreq_add_dev (struct sys_device * sys_dev) * CPU because it is in the same boat. */ policy = cpufreq_cpu_get(cpu); if (unlikely(policy)) { - dprintk("CPU already managed, adding link\n"); - sysfs_create_link(&sys_dev->kobj, &policy->kobj, "cpufreq"); + cpufreq_cpu_put(policy); cpufreq_debug_enable_ratelimit(); return 0; } @@ -623,6 +628,32 @@ static int cpufreq_add_dev (struct sys_device * sys_dev) goto err_out; } +#ifdef CONFIG_SMP + for_each_cpu_mask(j, policy->cpus) { + if (cpu == j) + continue; + + /* check for existing affected CPUs. They may not be aware + * of it due to CPU Hotplug. + */ + managed_policy = cpufreq_cpu_get(j); + if (unlikely(managed_policy)) { + spin_lock_irqsave(&cpufreq_driver_lock, flags); + managed_policy->cpus = policy->cpus; + cpufreq_cpu_data[cpu] = managed_policy; + spin_unlock_irqrestore(&cpufreq_driver_lock, flags); + + dprintk("CPU already managed, adding link\n"); + sysfs_create_link(&sys_dev->kobj, + &managed_policy->kobj, "cpufreq"); + + cpufreq_debug_enable_ratelimit(); + mutex_unlock(&policy->lock); + ret = 0; + goto err_out_driver_exit; /* call driver->exit() */ + } + } +#endif memcpy(&new_policy, policy, sizeof(struct cpufreq_policy)); /* prepare interface data */ @@ -650,6 +681,21 @@ static int cpufreq_add_dev (struct sys_device * sys_dev) for_each_cpu_mask(j, policy->cpus) cpufreq_cpu_data[j] = policy; spin_unlock_irqrestore(&cpufreq_driver_lock, flags); + + /* symlink affected CPUs */ + for_each_cpu_mask(j, policy->cpus) { + if (j == cpu) + continue; + if (!cpu_online(j)) + continue; + + dprintk("CPU already managed, adding link\n"); + cpufreq_cpu_get(cpu); + cpu_sys_dev = get_cpu_sysdev(j); + sysfs_create_link(&cpu_sys_dev->kobj, &policy->kobj, + "cpufreq"); + } + policy->governor = NULL; /* to assure that the starting sequence is * run in cpufreq_set_policy */ mutex_unlock(&policy->lock); @@ -728,6 +774,7 @@ static int cpufreq_remove_dev (struct sys_device * sys_dev) */ if (unlikely(cpu != data->cpu)) { dprintk("removing link\n"); + cpu_clear(cpu, data->cpus); spin_unlock_irqrestore(&cpufreq_driver_lock, flags); sysfs_remove_link(&sys_dev->kobj, "cpufreq"); cpufreq_cpu_put(data); -- 2.39.5