locking, ACPI: Annotate c3_lock as raw

We cannot preempt this lock on -rt as we are in an
interrupt disabled region and about to go into deep sleep.

In mainline this change documents the low level nature of
the lock - otherwise there's no functional difference. Lockdep
and Sparse checking will work as usual.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Len Brown <len.brown@intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

drivers/acpi/processor_idle.c

@@ -852,7 +852,7 @@ static int acpi_idle_enter_simple(struct cpuidle_device *dev,
 }
 
 static int c3_cpu_count;
-static DEFINE_SPINLOCK(c3_lock);
+static DEFINE_RAW_SPINLOCK(c3_lock);
 
 /**
  * acpi_idle_enter_bm - enters C3 with proper BM handling
@@ -930,12 +930,12 @@ static int acpi_idle_enter_bm(struct cpuidle_device *dev,
 	 * without doing anything.
 	 */
 	if (pr->flags.bm_check && pr->flags.bm_control) {
-		spin_lock(&c3_lock);
+		raw_spin_lock(&c3_lock);
 		c3_cpu_count++;
 		/* Disable bus master arbitration when all CPUs are in C3 */
 		if (c3_cpu_count == num_online_cpus())
 			acpi_write_bit_register(ACPI_BITREG_ARB_DISABLE, 1);
-		spin_unlock(&c3_lock);
+		raw_spin_unlock(&c3_lock);
 	} else if (!pr->flags.bm_check) {
 		ACPI_FLUSH_CPU_CACHE();
 	}
@@ -944,10 +944,10 @@ static int acpi_idle_enter_bm(struct cpuidle_device *dev,
 
 	/* Re-enable bus master arbitration */
 	if (pr->flags.bm_check && pr->flags.bm_control) {
-		spin_lock(&c3_lock);
+		raw_spin_lock(&c3_lock);
 		acpi_write_bit_register(ACPI_BITREG_ARB_DISABLE, 0);
 		c3_cpu_count--;
-		spin_unlock(&c3_lock);
+		raw_spin_unlock(&c3_lock);
 	}
 	kt2 = ktime_get_real();
 	idle_time_ns = ktime_to_ns(ktime_sub(kt2, kt1));