x86-mce-timer-hrtimer.patch

From: Thomas Gleixner <tglx@linutronix.de>
Date: Mon, 13 Dec 2010 16:33:39 +0100
Subject: x86: Convert mce timer to hrtimer

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>

---
 arch/x86/kernel/cpu/mcheck/mce.c |   36 ++++++++++++++++--------------------
 1 file changed, 16 insertions(+), 20 deletions(-)

Index: linux-stable/arch/x86/kernel/cpu/mcheck/mce.c
===================================================================
--- linux-stable.orig/arch/x86/kernel/cpu/mcheck/mce.c
+++ linux-stable/arch/x86/kernel/cpu/mcheck/mce.c
@@ -41,6 +41,7 @@
 #include <linux/debugfs.h>
 #include <linux/irq_work.h>
 #include <linux/export.h>
+#include <linux/jiffies.h>
 
 #include <asm/processor.h>
 #include <asm/mce.h>
@@ -1264,15 +1265,12 @@ void mce_log_therm_throt_event(__u64 sta
 static unsigned long check_interval = 5 * 60; /* 5 minutes */
 
 static DEFINE_PER_CPU(unsigned long, mce_next_interval); /* in jiffies */
-static DEFINE_PER_CPU(struct timer_list, mce_timer);
+static DEFINE_PER_CPU(struct hrtimer, mce_timer);
 
-static void mce_timer_fn(unsigned long data)
+static enum hrtimer_restart mce_timer_fn(struct hrtimer *timer)
 {
-	struct timer_list *t = &__get_cpu_var(mce_timer);
 	unsigned long iv;
 
-	WARN_ON(smp_processor_id() != data);
-
 	if (mce_available(__this_cpu_ptr(&cpu_info))) {
 		machine_check_poll(MCP_TIMESTAMP,
 				&__get_cpu_var(mce_poll_banks));
@@ -1289,17 +1287,18 @@ static void mce_timer_fn(unsigned long d
 		iv = min(iv * 2, round_jiffies_relative(check_interval * HZ));
 	__this_cpu_write(mce_next_interval, iv);
 
-	t->expires = jiffies + iv;
-	add_timer_on(t, smp_processor_id());
+	hrtimer_forward(timer, timer->base->get_time(),
+			ns_to_ktime(jiffies_to_usecs(iv)));
+	return HRTIMER_RESTART;
 }
 
-/* Must not be called in IRQ context where del_timer_sync() can deadlock */
+/* Must not be called in IRQ context where hrtimer_cancel() can deadlock */
 static void mce_timer_delete_all(void)
 {
 	int cpu;
 
 	for_each_online_cpu(cpu)
-		del_timer_sync(&per_cpu(mce_timer, cpu));
+		hrtimer_cancel(&per_cpu(mce_timer, cpu));
 }
 
 static void mce_do_trigger(struct work_struct *work)
@@ -1596,10 +1595,11 @@ static void __mcheck_cpu_init_vendor(str
 
 static void __mcheck_cpu_init_timer(void)
 {
-	struct timer_list *t = &__get_cpu_var(mce_timer);
+	struct hrtimer *t = &__get_cpu_var(mce_timer);
 	unsigned long iv = check_interval * HZ;
 
-	setup_timer(t, mce_timer_fn, smp_processor_id());
+	hrtimer_init(t, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
+	t->function = mce_timer_fn;
 
 	if (mce_ignore_ce)
 		return;
@@ -1607,8 +1607,8 @@ static void __mcheck_cpu_init_timer(void
 	__this_cpu_write(mce_next_interval, iv);
 	if (!iv)
 		return;
-	t->expires = round_jiffies(jiffies + iv);
-	add_timer_on(t, smp_processor_id());
+	hrtimer_start_range_ns(t, ns_to_ktime(jiffies_to_usecs(iv) * 1000),
+			       0, HRTIMER_MODE_REL_PINNED);
 }
 
 /* Handle unconfigured int18 (should never happen) */
@@ -2259,6 +2259,8 @@ static void __cpuinit mce_disable_cpu(vo
 	if (!mce_available(__this_cpu_ptr(&cpu_info)))
 		return;
 
+	hrtimer_cancel(&__get_cpu_var(mce_timer));
+
 	if (!(action & CPU_TASKS_FROZEN))
 		cmci_clear();
 	for (i = 0; i < banks; i++) {
@@ -2285,6 +2287,7 @@ static void __cpuinit mce_reenable_cpu(v
 		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. */
@@ -2292,7 +2295,6 @@ 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:
@@ -2309,16 +2311,10 @@ mce_cpu_callback(struct notifier_block *
 		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 +
-					per_cpu(mce_next_interval, cpu));
-			add_timer_on(t, cpu);
-		}
 		smp_call_function_single(cpu, mce_reenable_cpu, &action, 1);
 		break;
 	case CPU_POST_DEAD: