Messages in this thread Patch in this message | | | Date | Mon, 8 Jun 2009 09:13:29 -0700 | From | "Paul E. McKenney" <> | Subject | Re: [PATCH 3/5] can: af_can.c use rcu_barrier() on module unload. |
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On Mon, Jun 08, 2009 at 03:11:38PM +0200, Jesper Dangaard Brouer wrote: > This module uses rcu_call() thus it should use rcu_barrier() > on module unload.
This does appear to make things better!!!
However, I don't understand why it is safe to do the following in can_exit():
hlist_for_each_entry_safe(d, n, next, &can_rx_dev_list, list) { hlist_del(&d->list); kfree(d); }
Given that this list is scanned by RCU readers, shouldn't this kfree() be something like "call_rcu(&d->rcu, can_rx_delete_device);"?
Also, what frees up the "struct receiver" structures?
Thanx, Paul
> Signed-off-by: Jesper Dangaard Brouer <hawk@comx.dk> > --- > > net/can/af_can.c | 2 ++ > 1 files changed, 2 insertions(+), 0 deletions(-) > > diff --git a/net/can/af_can.c b/net/can/af_can.c > index 10f0528..e733725 100644 > --- a/net/can/af_can.c > +++ b/net/can/af_can.c > @@ -903,6 +903,8 @@ static __exit void can_exit(void) > } > spin_unlock(&can_rcvlists_lock); > > + rcu_barrier(); /* Wait for completion of call_rcu()'s */ > + > kmem_cache_destroy(rcv_cache); > } > >
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