mm, slub: only disable irq with spin_lock in __unfreeze_partials()

__unfreeze_partials() no longer needs to have irqs disabled, except for making
the spin_lock operations irq-safe, so convert the spin_locks operations and
remove the separate irq handling.
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>

mm/slub.c

@@ -2352,9 +2352,7 @@ static void __unfreeze_partials(struct kmem_cache *s, struct page *partial_page)
 {
 	struct kmem_cache_node *n = NULL, *n2 = NULL;
 	struct page *page, *discard_page = NULL;
-	unsigned long flags;
-
-	local_irq_save(flags);
+	unsigned long flags = 0;
 
 	while (partial_page) {
 		struct page new;
@@ -2366,10 +2364,10 @@ static void __unfreeze_partials(struct kmem_cache *s, struct page *partial_page)
 		n2 = get_node(s, page_to_nid(page));
 		if (n != n2) {
 			if (n)
-				spin_unlock(&n->list_lock);
+				spin_unlock_irqrestore(&n->list_lock, flags);
 
 			n = n2;
-			spin_lock(&n->list_lock);
+			spin_lock_irqsave(&n->list_lock, flags);
 		}
 
 		do {
@@ -2398,9 +2396,7 @@ static void __unfreeze_partials(struct kmem_cache *s, struct page *partial_page)
 	}
 
 	if (n)
-		spin_unlock(&n->list_lock);
-
-	local_irq_restore(flags);
+		spin_unlock_irqrestore(&n->list_lock, flags);
 
 	while (discard_page) {
 		page = discard_page;