[PARISC] pdc_console: fix bizarre panic on boot

[sfrench/cifs-2.6.git] / lib / percpu_counter.c

diff --git a/lib/percpu_counter.c b/lib/percpu_counter.c
index 850449080e1cfb7f619eca4ae5d5ed6aca01a1d0..393a0e915c23b252b747c62645beb463e25843ed 100644 (file)
--- a/lib/percpu_counter.c
+++ b/lib/percpu_counter.c
@@ -3,17 +3,40 @@
  */
 
 #include <linux/percpu_counter.h>
+#include <linux/notifier.h>
+#include <linux/mutex.h>
+#include <linux/init.h>
+#include <linux/cpu.h>
 #include <linux/module.h>
 
-void percpu_counter_mod(struct percpu_counter *fbc, s32 amount)
+#ifdef CONFIG_HOTPLUG_CPU
+static LIST_HEAD(percpu_counters);
+static DEFINE_MUTEX(percpu_counters_lock);
+#endif
+
+void percpu_counter_set(struct percpu_counter *fbc, s64 amount)
+{
+       int cpu;
+
+       spin_lock(&fbc->lock);
+       for_each_possible_cpu(cpu) {
+               s32 *pcount = per_cpu_ptr(fbc->counters, cpu);
+               *pcount = 0;
+       }
+       fbc->count = amount;
+       spin_unlock(&fbc->lock);
+}
+EXPORT_SYMBOL(percpu_counter_set);
+
+void __percpu_counter_add(struct percpu_counter *fbc, s64 amount, s32 batch)
 {
-       long count;
+       s64 count;
        s32 *pcount;
        int cpu = get_cpu();
 
        pcount = per_cpu_ptr(fbc->counters, cpu);
        count = *pcount + amount;
-       if (count >= FBC_BATCH || count <= -FBC_BATCH) {
+       if (count >= batch || count <= -batch) {
                spin_lock(&fbc->lock);
                fbc->count += count;
                *pcount = 0;
@@ -23,24 +46,100 @@ void percpu_counter_mod(struct percpu_counter *fbc, s32 amount)
        }
        put_cpu();
 }
-EXPORT_SYMBOL(percpu_counter_mod);
+EXPORT_SYMBOL(__percpu_counter_add);
 
 /*
  * Add up all the per-cpu counts, return the result.  This is a more accurate
  * but much slower version of percpu_counter_read_positive()
  */
-s64 percpu_counter_sum(struct percpu_counter *fbc)
+s64 __percpu_counter_sum(struct percpu_counter *fbc)
 {
        s64 ret;
        int cpu;
 
        spin_lock(&fbc->lock);
        ret = fbc->count;
-       for_each_possible_cpu(cpu) {
+       for_each_online_cpu(cpu) {
                s32 *pcount = per_cpu_ptr(fbc->counters, cpu);
                ret += *pcount;
        }
        spin_unlock(&fbc->lock);
-       return ret < 0 ? 0 : ret;
+       return ret;
+}
+EXPORT_SYMBOL(__percpu_counter_sum);
+
+static struct lock_class_key percpu_counter_irqsafe;
+
+int percpu_counter_init(struct percpu_counter *fbc, s64 amount)
+{
+       spin_lock_init(&fbc->lock);
+       fbc->count = amount;
+       fbc->counters = alloc_percpu(s32);
+       if (!fbc->counters)
+               return -ENOMEM;
+#ifdef CONFIG_HOTPLUG_CPU
+       mutex_lock(&percpu_counters_lock);
+       list_add(&fbc->list, &percpu_counters);
+       mutex_unlock(&percpu_counters_lock);
+#endif
+       return 0;
+}
+EXPORT_SYMBOL(percpu_counter_init);
+
+int percpu_counter_init_irq(struct percpu_counter *fbc, s64 amount)
+{
+       int err;
+
+       err = percpu_counter_init(fbc, amount);
+       if (!err)
+               lockdep_set_class(&fbc->lock, &percpu_counter_irqsafe);
+       return err;
+}
+
+void percpu_counter_destroy(struct percpu_counter *fbc)
+{
+       if (!fbc->counters)
+               return;
+
+       free_percpu(fbc->counters);
+#ifdef CONFIG_HOTPLUG_CPU
+       mutex_lock(&percpu_counters_lock);
+       list_del(&fbc->list);
+       mutex_unlock(&percpu_counters_lock);
+#endif
+}
+EXPORT_SYMBOL(percpu_counter_destroy);
+
+#ifdef CONFIG_HOTPLUG_CPU
+static int __cpuinit percpu_counter_hotcpu_callback(struct notifier_block *nb,
+                                       unsigned long action, void *hcpu)
+{
+       unsigned int cpu;
+       struct percpu_counter *fbc;
+
+       if (action != CPU_DEAD)
+               return NOTIFY_OK;
+
+       cpu = (unsigned long)hcpu;
+       mutex_lock(&percpu_counters_lock);
+       list_for_each_entry(fbc, &percpu_counters, list) {
+               s32 *pcount;
+               unsigned long flags;
+
+               spin_lock_irqsave(&fbc->lock, flags);
+               pcount = per_cpu_ptr(fbc->counters, cpu);
+               fbc->count += *pcount;
+               *pcount = 0;
+               spin_unlock_irqrestore(&fbc->lock, flags);
+       }
+       mutex_unlock(&percpu_counters_lock);
+       return NOTIFY_OK;
+}
+
+static int __init percpu_counter_startup(void)
+{
+       hotcpu_notifier(percpu_counter_hotcpu_callback, 0);
+       return 0;
 }
-EXPORT_SYMBOL(percpu_counter_sum);
+module_init(percpu_counter_startup);
+#endif