Subject: mm: workingset: replace IRQ-off check with a lockdep assert.
From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Date: Mon Feb 11 10:40:46 2019 +0100

From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>

Commit

  68d48e6a2df57 ("mm: workingset: add vmstat counter for shadow nodes")

introduced an IRQ-off check to ensure that a lock is held which also
disabled interrupts. This does not work the same way on -RT because none
of the locks, that are held, disable interrupts.
Replace this check with a lockdep assert which ensures that the lock is
held.

Cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lkml.kernel.org/r/20190211113829.sqf6bdi4c4cdd3rp@linutronix.de
---
 mm/workingset.c |    5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)
---
--- a/mm/workingset.c
+++ b/mm/workingset.c
@@ -433,6 +433,8 @@ static struct list_lru shadow_nodes;
 
 void workingset_update_node(struct xa_node *node)
 {
+	struct address_space *mapping;
+
 	/*
 	 * Track non-empty nodes that contain only shadow entries;
 	 * unlink those that contain pages or are being freed.
@@ -441,7 +443,8 @@ void workingset_update_node(struct xa_no
 	 * already where they should be. The list_empty() test is safe
 	 * as node->private_list is protected by the i_pages lock.
 	 */
-	VM_WARN_ON_ONCE(!irqs_disabled());  /* For __inc_lruvec_page_state */
+	mapping = container_of(node->array, struct address_space, i_pages);
+	lockdep_assert_held(&mapping->i_pages.xa_lock);
 
 	if (node->count && node->count == node->nr_values) {
 		if (list_empty(&node->private_list)) {