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()
the lookup met the end of chain. If final 'nulls' value
is not the slot number, then we must restart the lookup at
the beginning. If the object was moved to the same chain,
-then the reader doesnt care : It might eventually
+then the reader doesn't care : It might eventually
scan the list again without harm.
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)