sched/mm: call finish_arch_post_lock_switch in idle_task_exit and use_mm

Martin Schwidefsky · Martin Schwidefsky · commit a53efe5ff88d · 2014-02-21T08:50:17.000+01:00
The finish_arch_post_lock_switch is called at the end of the task
switch after all locks have been released. In concept it is paired
with the switch_mm function, but the current code only does the
call in finish_task_switch. Add the call to idle_task_exit and
use_mm. One use case for the additional calls is s390 which will
use finish_arch_post_lock_switch to wait for the completion of
TLB flush operations.

Signed-off-by: Martin Schwidefsky &lt;schwidefsky@de.ibm.com&gt;
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
@@ -4692,8 +4692,10 @@ void idle_task_exit(void)
 
 	BUG_ON(cpu_online(smp_processor_id()));
 
-	if (mm != &init_mm)
+	if (mm != &init_mm) {
 		switch_mm(mm, &init_mm, current);
+		finish_arch_post_lock_switch();
+	}
 	mmdrop(mm);
 }
 
diff --git a/mm/mmu_context.c b/mm/mmu_context.c
@@ -31,6 +31,9 @@ void use_mm(struct mm_struct *mm)
 	tsk->mm = mm;
 	switch_mm(active_mm, mm, tsk);
 	task_unlock(tsk);
+#ifdef finish_arch_post_lock_switch
+	finish_arch_post_lock_switch();
+#endif
 
 	if (active_mm != mm)
 		mmdrop(active_mm);

Original file line number	Diff line number	Diff line change
`@@ -4692,8 +4692,10 @@ void idle_task_exit(void)`
`4692`	`4692`
`4693`	`4693`	`BUG_ON(cpu_online(smp_processor_id()));`
`4694`	`4694`
`4695`		`- if (mm != &init_mm)`
	`4695`	`+ if (mm != &init_mm) {`
`4696`	`4696`	`switch_mm(mm, &init_mm, current);`
	`4697`	`+ finish_arch_post_lock_switch();`
	`4698`	`+ }`
`4697`	`4699`	`mmdrop(mm);`
`4698`	`4700`	`}`
`4699`	`4701`