From 67b6c900dc6dce65478d6fe37b60cd1e65bb80c2 Mon Sep 17 00:00:00 2001 From: Dave Hansen Date: Fri, 24 Jan 2014 07:20:23 -0800 Subject: [PATCH] mm: slub: work around unneeded lockdep warning The slub code does some setup during early boot in early_kmem_cache_node_alloc() with some local data. There is no possible way that another CPU can see this data, so the slub code doesn't unnecessarily lock it. However, some new lockdep asserts check to make sure that add_partial() _always_ has the list_lock held. Just add the locking, even though it is technically unnecessary. Cc: Peter Zijlstra Cc: Russell King Acked-by: David Rientjes Signed-off-by: Dave Hansen Signed-off-by: Pekka Enberg --- mm/slub.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/mm/slub.c b/mm/slub.c index a99e9e67c60e..432bddf484bb 100644 --- a/mm/slub.c +++ b/mm/slub.c @@ -2890,7 +2890,13 @@ static void early_kmem_cache_node_alloc(int node) init_kmem_cache_node(n); inc_slabs_node(kmem_cache_node, node, page->objects); + /* + * the lock is for lockdep's sake, not for any actual + * race protection + */ + spin_lock(&n->list_lock); add_partial(n, page, DEACTIVATE_TO_HEAD); + spin_unlock(&n->list_lock); } static void free_kmem_cache_nodes(struct kmem_cache *s) -- 2.20.1