[144/227] mm: workingset: replace IRQ-off check with a lockdep assert.

Commit Message

Andrew Morton March 22, 2022, 9:45 p.m. UTC

From: Sebastian Andrzej Siewior <[e-mail]>
Subject: mm: workingset: replace IRQ-off check with a lockdep assert.

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 PREEMPT_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.

Link: https://lkml.kernel.org/r/[e-mail]
Signed-off-by: Sebastian Andrzej Siewior <[e-mail]>
Cc: Johannes Weiner <[e-mail]>
Cc: Tejun Heo <[e-mail]>
Cc: Zefan Li <[e-mail]>
Cc: Thomas Gleixner <[e-mail]>
Signed-off-by: Andrew Morton <[e-mail]>
---

 mm/workingset.c |    5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

Patch

--- a/mm/workingset.c~mm-workingset-replace-irq-off-check-with-a-lockdep-assert
+++ a/mm/workingset.c
@@ -433,6 +433,8 @@  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)) {