treewide: fix synchronize_rcu() in comments

Signed-off-by: Jesper Dangaard Brouer <[e-mail]>
Signed-off-by: Jiri Kosina <[e-mail]>

include/linux/percpu-refcount.h

···
  * calls io_destroy() or the process exits.
  *
  * In the aio code, kill_ioctx() is called when we wish to destroy a kioctx; it
- * calls percpu_ref_kill(), then hlist_del_rcu() and sychronize_rcu() to remove
+ * calls percpu_ref_kill(), then hlist_del_rcu() and synchronize_rcu() to remove
  * the kioctx from the proccess's list of kioctxs - after that, there can't be
  * any new users of the kioctx (from lookup_ioctx()) and it's then safe to drop
  * the initial ref with percpu_ref_put().

net/rds/af_rds.c

···
 
 	/*
 	 * the binding lookup hash uses rcu, we need to
-	 * make sure we sychronize_rcu before we free our
+	 * make sure we synchronize_rcu before we free our
 	 * entry
 	 */
 	rds_remove_bound(rs);