Merge tag 'v4.1.5-rt5-lno1' of git://git.linaro.org/people/anders.roxell/linux-rt into linux-linaro-lsk-v4.1-rtlsk-v4.1-15.08-rt

Linux 4.1.5-rt5

Changes since v4.1.3-rt3
- don't disable preemption in dump_stack(). We should not see a
  backtrace on a production kernel but then it should not increase the
  latency if trigger one.

* tag 'v4.1.5-rt5-lno1' of git://git.linaro.org/people/anders.roxell/linux-rt: (270 commits)
  localversion: Add RT specific localversion file
  workqueue: Prevent deadlock/stall on RT
  md: disable bcache
  rt,ntp: Move call to schedule_delayed_work() to helper thread
  memcontrol: Prevent scheduling while atomic in cgroup code
  cgroups: use simple wait in css_release()
  i915: bogus warning from i915 when running on PREEMPT_RT
  drm/i915: drop trace_i915_gem_ring_dispatch on rt
  gpu/i915: don't open code these things
  cpufreq: drop K8's driver from beeing selected
  mmc: sdhci: don't provide hard irq handler
  mmci: Remove bogus local_irq_save()
  i2c/omap: drop the lock hard irq context
  leds: trigger: disable CPU trigger on -RT
  arch/arm64: Add lazy preempt support
  powerpc: Add support for lazy preemption
  arm: Add support for lazy preemption
  x86: Support for lazy preemption
  sched: Add support for lazy preemption
  rcu: make RCU_BOOST default on RT
  ...

4 files changed, 9 insertions, 9 deletions

diff --git a/arch/x86/kernel/dumpstack_32.c b/arch/x86/kernel/dumpstack_32.c
index 464ffd69b92e..00db1aad1548 100644
--- a/arch/x86/kernel/dumpstack_32.c
+++ b/arch/x86/kernel/dumpstack_32.c
@@ -42,7 +42,7 @@ void dump_trace(struct task_struct *task, struct pt_regs *regs,
 		unsigned long *stack, unsigned long bp,
 		const struct stacktrace_ops *ops, void *data)
 {
-	const unsigned cpu = get_cpu();
+	const unsigned cpu = get_cpu_light();
 	int graph = 0;
 	u32 *prev_esp;
 
@@ -86,7 +86,7 @@ void dump_trace(struct task_struct *task, struct pt_regs *regs,
 			break;
 		touch_nmi_watchdog();
 	}
-	put_cpu();
+	put_cpu_light();
 }
 EXPORT_SYMBOL(dump_trace);
 
diff --git a/arch/x86/kernel/dumpstack_64.c b/arch/x86/kernel/dumpstack_64.c
index 5f1c6266eb30..c331e3fef465 100644
--- a/arch/x86/kernel/dumpstack_64.c
+++ b/arch/x86/kernel/dumpstack_64.c
@@ -152,7 +152,7 @@ void dump_trace(struct task_struct *task, struct pt_regs *regs,
 		unsigned long *stack, unsigned long bp,
 		const struct stacktrace_ops *ops, void *data)
 {
-	const unsigned cpu = get_cpu();
+	const unsigned cpu = get_cpu_light();
 	struct thread_info *tinfo;
 	unsigned long *irq_stack = (unsigned long *)per_cpu(irq_stack_ptr, cpu);
 	unsigned long dummy;
@@ -241,7 +241,7 @@ void dump_trace(struct task_struct *task, struct pt_regs *regs,
 	 * This handles the process stack:
 	 */
 	bp = ops->walk_stack(tinfo, stack, bp, ops, data, NULL, &graph);
-	put_cpu();
+	put_cpu_light();
 }
 EXPORT_SYMBOL(dump_trace);
 
@@ -255,7 +255,7 @@ show_stack_log_lvl(struct task_struct *task, struct pt_regs *regs,
 	int cpu;
 	int i;
 
-	preempt_disable();
+	migrate_disable();
 	cpu = smp_processor_id();
 
 	irq_stack_end	= (unsigned long *)(per_cpu(irq_stack_ptr, cpu));
@@ -291,7 +291,7 @@ show_stack_log_lvl(struct task_struct *task, struct pt_regs *regs,
 			pr_cont(" %016lx", *stack++);
 		touch_nmi_watchdog();
 	}
-	preempt_enable();
+	migrate_enable();
 
 	pr_cont("\n");
 	show_trace_log_lvl(task, regs, sp, bp, log_lvl);
diff --git a/lib/dump_stack.c b/lib/dump_stack.c
index 6745c6230db3..7ccbc6ff80ea 100644
--- a/lib/dump_stack.c
+++ b/lib/dump_stack.c
@@ -33,7 +33,7 @@ asmlinkage __visible void dump_stack(void)
 	 * Permit this cpu to perform nested stack dumps while serialising
 	 * against other CPUs
 	 */
-	preempt_disable();
+	migrate_disable();
 
 retry:
 	cpu = smp_processor_id();
@@ -52,7 +52,7 @@ retry:
 	if (!was_locked)
 		atomic_set(&dump_lock, -1);
 
-	preempt_enable();
+	migrate_enable();
 }
 #else
 asmlinkage __visible void dump_stack(void)
diff --git a/localversion-rt b/localversion-rt
index 1445cd65885c..0efe7ba1930e 100644
--- a/localversion-rt
+++ b/localversion-rt
@@ -1 +1 @@
--rt3
+-rt5