[patch 3/4] sched/mmcid: Remove pointless preempt guard

[Thomas Gleixner]

This is a leftover from the early versions of this function where it could
be invoked without mm::mm_cid::lock held.

Remove it and add lockdep asserts instead.

Fixes: 653fda7ae73d ("sched/mmcid: Switch over to the new mechanism")
Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxx>
---
 kernel/sched/core.c |   12 +++++++-----
 1 file changed, 7 insertions(+), 5 deletions(-)

--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -10685,6 +10685,8 @@ static void mm_cid_fixup_tasks_to_cpus(v
 
 static bool sched_mm_cid_add_user(struct task_struct *t, struct mm_struct *mm)
 {
+	lockdep_assert_held(&mm->mm_cid.lock);
+
 	t->mm_cid.active = 1;
 	mm->mm_cid.users++;
 	return mm_update_max_cids(mm);
@@ -10737,12 +10739,12 @@ static void sched_mm_cid_fork(struct tas
 
 static bool sched_mm_cid_remove_user(struct task_struct *t)
 {
+	lockdep_assert_held(&t->mm->mm_cid.lock);
+
 	t->mm_cid.active = 0;
-	scoped_guard(preempt) {
-		/* Clear the transition bit */
-		t->mm_cid.cid = cid_from_transit_cid(t->mm_cid.cid);
-		mm_unset_cid_on_task(t);
-	}
+	/* Clear the transition bit */
+	t->mm_cid.cid = cid_from_transit_cid(t->mm_cid.cid);
+	mm_unset_cid_on_task(t);
 	t->mm->mm_cid.users--;
 	return mm_update_max_cids(t->mm);
 }