mm: workingset: make shadow_lru_isolate() use locking suffix

shadow_lru_isolate() disables interrupts and acquires a lock.  It could
use spin_lock_irq() instead.  It also uses local_irq_enable() while it
could use spin_unlock_irq()/xa_unlock_irq().

Use proper suffix for lock/unlock in order to enable/disable interrupts
during release/acquire of a lock.

Link: http://lkml.kernel.org/r/20180622151221.28167-3-bigeasy@linutronix.de
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Kirill Tkhai <ktkhai@virtuozzo.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm/workingset.c

@@ -431,7 +431,7 @@ static enum lru_status shadow_lru_isolate(struct list_head *item,
 
 	/* Coming from the list, invert the lock order */
 	if (!xa_trylock(&mapping->i_pages)) {
-		spin_unlock(lru_lock);
+		spin_unlock_irq(lru_lock);
 		ret = LRU_RETRY;
 		goto out;
 	}
@@ -469,13 +469,11 @@ static enum lru_status shadow_lru_isolate(struct list_head *item,
 				 workingset_lookup_update(mapping));
 
 out_invalid:
-	xa_unlock(&mapping->i_pages);
+	xa_unlock_irq(&mapping->i_pages);
 	ret = LRU_REMOVED_RETRY;
 out:
-	local_irq_enable();
 	cond_resched();
-	local_irq_disable();
-	spin_lock(lru_lock);
+	spin_lock_irq(lru_lock);
 	return ret;
 }