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authorIngo Molnar <mingo@elte.hu>2009-08-11 14:19:09 +0200
committerIngo Molnar <mingo@elte.hu>2009-08-11 14:19:09 +0200
commit89034bc2c7b839702c00a704e79d112737f98be0 (patch)
treee65b1f3d4c751baa840efc81bc4734f089379eb3 /Documentation/RCU/rculist_nulls.txt
parentfb82ad719831db58e9baa4c67015aae3fe27e7e3 (diff)
parent85dfd81dc57e8183a277ddd7a56aa65c96f3f487 (diff)
downloadlwn-89034bc2c7b839702c00a704e79d112737f98be0.tar.gz
lwn-89034bc2c7b839702c00a704e79d112737f98be0.zip
Merge branch 'linus' into tracing/core
Conflicts: kernel/trace/trace_events_filter.c We use the tracing/core version. Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'Documentation/RCU/rculist_nulls.txt')
-rw-r--r--Documentation/RCU/rculist_nulls.txt7
1 files changed, 6 insertions, 1 deletions
diff --git a/Documentation/RCU/rculist_nulls.txt b/Documentation/RCU/rculist_nulls.txt
index 93cb28d05dcd..18f9651ff23d 100644
--- a/Documentation/RCU/rculist_nulls.txt
+++ b/Documentation/RCU/rculist_nulls.txt
@@ -83,11 +83,12 @@ not detect it missed following items in original chain.
obj = kmem_cache_alloc(...);
lock_chain(); // typically a spin_lock()
obj->key = key;
-atomic_inc(&obj->refcnt);
/*
* we need to make sure obj->key is updated before obj->next
+ * or obj->refcnt
*/
smp_wmb();
+atomic_set(&obj->refcnt, 1);
hlist_add_head_rcu(&obj->obj_node, list);
unlock_chain(); // typically a spin_unlock()
@@ -159,6 +160,10 @@ out:
obj = kmem_cache_alloc(cachep);
lock_chain(); // typically a spin_lock()
obj->key = key;
+/*
+ * changes to obj->key must be visible before refcnt one
+ */
+smp_wmb();
atomic_set(&obj->refcnt, 1);
/*
* insert obj in RCU way (readers might be traversing chain)