x86-Convert-mce-timer-to-hrtimer.patch

From 76bdf0c3151369f5b15af4baac2708e59347d664 Mon Sep 17 00:00:00 2001
From: Thomas Gleixner <tglx@linutronix.de>
Date: Mon, 13 Dec 2010 16:33:39 +0100
Subject: [PATCH] x86: Convert mce timer to hrtimer

commit 76bdf0c3151369f5b15af4baac2708e59347d664 in tip.

mce_timer is started in atomic contexts of cpu bringup. This results
in might_sleep() warnings on RT. Convert mce_timer to a hrtimer to
avoid this.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

diff --git a/arch/x86/kernel/cpu/mcheck/mce.c b/arch/x86/kernel/cpu/mcheck/mce.c
index a8aacd4..2b4aba9 100644
--- a/arch/x86/kernel/cpu/mcheck/mce.c
+++ b/arch/x86/kernel/cpu/mcheck/mce.c
@@ -35,6 +35,7 @@
 #include <linux/fs.h>
 #include <linux/mm.h>
 #include <linux/debugfs.h>
+#include <linux/jiffies.h>
 
 #include <asm/processor.h>
 #include <asm/hw_irq.h>
@@ -1131,17 +1132,14 @@ void mce_log_therm_throt_event(__u64 status)
  * poller finds an MCE, poll 2x faster.  When the poller finds no more
  * errors, poll 2x slower (up to check_interval seconds).
  */
-static int check_interval = 5 * 60; /* 5 minutes */
+static unsigned long check_interval = 5 * 60; /* 5 minutes */
 
-static DEFINE_PER_CPU(int, mce_next_interval); /* in jiffies */
-static DEFINE_PER_CPU(struct timer_list, mce_timer);
+static DEFINE_PER_CPU(unsigned long, mce_next_interval); /* in jiffies */
+static DEFINE_PER_CPU(struct hrtimer, mce_timer);
 
-static void mce_start_timer(unsigned long data)
+static enum hrtimer_restart mce_start_timer(struct hrtimer *timer)
 {
-	struct timer_list *t = &per_cpu(mce_timer, data);
-	int *n;
-
-	WARN_ON(smp_processor_id() != data);
+	unsigned long *n;
 
 	if (mce_available(&current_cpu_data)) {
 		machine_check_poll(MCP_TIMESTAMP,
@@ -1154,12 +1152,13 @@ static void mce_start_timer(unsigned long data)
 	 */
 	n = &__get_cpu_var(mce_next_interval);
 	if (mce_notify_irq())
-		*n = max(*n/2, HZ/100);
+		*n = max(*n/2, HZ/100UL);
 	else
-		*n = min(*n*2, (int)round_jiffies_relative(check_interval*HZ));
+		*n = min(*n*2, round_jiffies_relative(check_interval*HZ));
 
-	t->expires = jiffies + *n;
-	add_timer_on(t, smp_processor_id());
+	hrtimer_forward(timer, timer->base->get_time(),
+			ns_to_ktime(jiffies_to_usecs(*n) * 1000));
+	return HRTIMER_RESTART;
 }
 
 static void mce_do_trigger(struct work_struct *work)
@@ -1385,10 +1384,11 @@ static void __mcheck_cpu_init_vendor(struct cpuinfo_x86 *c)
 
 static void __mcheck_cpu_init_timer(void)
 {
-	struct timer_list *t = &__get_cpu_var(mce_timer);
-	int *n = &__get_cpu_var(mce_next_interval);
+	struct hrtimer *t = &__get_cpu_var(mce_timer);
+	unsigned long *n = &__get_cpu_var(mce_next_interval);
 
-	setup_timer(t, mce_start_timer, smp_processor_id());
+	hrtimer_init(t, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
+	t->function = mce_start_timer;
 
 	if (mce_ignore_ce)
 		return;
@@ -1396,8 +1396,9 @@ static void __mcheck_cpu_init_timer(void)
 	*n = check_interval * HZ;
 	if (!*n)
 		return;
-	t->expires = round_jiffies(jiffies + *n);
-	add_timer_on(t, smp_processor_id());
+
+	hrtimer_start_range_ns(t, ns_to_ktime(jiffies_to_usecs(*n) * 1000),
+			       0 , HRTIMER_MODE_REL_PINNED);
 }
 
 /* Handle unconfigured int18 (should never happen) */
@@ -1711,7 +1712,7 @@ static int mce_resume(struct sys_device *dev)
 
 static void mce_cpu_restart(void *data)
 {
-	del_timer_sync(&__get_cpu_var(mce_timer));
+	hrtimer_cancel(&__get_cpu_var(mce_timer));
 	if (!mce_available(&current_cpu_data))
 		return;
 	__mcheck_cpu_init_generic();
@@ -1730,7 +1731,7 @@ static void mce_disable_ce(void *all)
 	if (!mce_available(&current_cpu_data))
 		return;
 	if (all)
-		del_timer_sync(&__get_cpu_var(mce_timer));
+		hrtimer_cancel(&__get_cpu_var(mce_timer));
 	cmci_clear();
 }
 
@@ -1962,6 +1963,8 @@ static void __cpuinit mce_disable_cpu(void *h)
 	if (!mce_available(&current_cpu_data))
 		return;
 
+	hrtimer_cancel(&__get_cpu_var(mce_timer));
+
 	if (!(action & CPU_TASKS_FROZEN))
 		cmci_clear();
 	for (i = 0; i < banks; i++) {
@@ -1988,6 +1991,7 @@ static void __cpuinit mce_reenable_cpu(void *h)
 		if (b->init)
 			wrmsrl(MSR_IA32_MCx_CTL(i), b->ctl);
 	}
+	__mcheck_cpu_init_timer();
 }
 
 /* Get notified when a cpu comes on/off. Be hotplug friendly. */
@@ -1995,7 +1999,6 @@ static int __cpuinit
 mce_cpu_callback(struct notifier_block *nfb, unsigned long action, void *hcpu)
 {
 	unsigned int cpu = (unsigned long)hcpu;
-	struct timer_list *t = &per_cpu(mce_timer, cpu);
 
 	switch (action) {
 	case CPU_ONLINE:
@@ -2012,16 +2015,10 @@ mce_cpu_callback(struct notifier_block *nfb, unsigned long action, void *hcpu)
 		break;
 	case CPU_DOWN_PREPARE:
 	case CPU_DOWN_PREPARE_FROZEN:
-		del_timer_sync(t);
 		smp_call_function_single(cpu, mce_disable_cpu, &action, 1);
 		break;
 	case CPU_DOWN_FAILED:
 	case CPU_DOWN_FAILED_FROZEN:
-		if (!mce_ignore_ce && check_interval) {
-			t->expires = round_jiffies(jiffies +
-					   __get_cpu_var(mce_next_interval));
-			add_timer_on(t, cpu);
-		}
 		smp_call_function_single(cpu, mce_reenable_cpu, &action, 1);
 		break;
 	case CPU_POST_DEAD:
-- 
1.7.1.1