On Tue, 2009-06-23 at 17:15 +0200, Johannes Berg wrote: > On Tue, 2009-06-23 at 17:04 +0200, Jesper Dangaard Brouer wrote: > > The mac80211 module uses rcu_call() thus it should use rcu_barrier() > > on module unload. > > > > I'm having a hardtime verifying that no more call_rcu() callbacks can > > be schedules in the module unload path. Could a maintainer please > > look into this? > > > > Signed-off-by: Jesper Dangaard Brouer <hawk@xxxxxxx> > > --- > > > > net/mac80211/main.c | 2 ++ > > 1 files changed, 2 insertions(+), 0 deletions(-) > > > > diff --git a/net/mac80211/main.c b/net/mac80211/main.c > > index 092a017..e9f70ce 100644 > > --- a/net/mac80211/main.c > > +++ b/net/mac80211/main.c > > @@ -1100,6 +1100,8 @@ static void __exit ieee80211_exit(void) > > ieee80211s_stop(); > > > > ieee80211_debugfs_netdev_exit(); > > + > > + rcu_barrier(); /* Wait for completion of call_rcu()'s */ > > } > > I don't think this is correct at all -- note that call_rcu() is done in > some of the mesh code, so I would think you need to do this in > ieee80211_stop() since the call_rcu() code requires the interface to > still be around. And when it's stopped everything should be idle. Should it then not be in mesh.c ieee80211_stop_mesh(). We can replace the synchronize_rcu() in this function with a rcu_barrier(). > I can fix it later, but I'm deep in some other stuff right now. Yes, I noticed you seem quite active :-) I can also do a repost... what about the patch below? -- Med venlig hilsen / Best regards Jesper Brouer ComX Networks A/S Linux Network developer Cand. Scient Datalog / MSc. Author of http://adsl-optimizer.dk LinkedIn: http://www.linkedin.com/in/brouer [PATCH v2 03/10] mac80211: Use rcu_barrier() on unload. From: Jesper Dangaard Brouer <hawk@xxxxxxx> The mac80211 module uses rcu_call() thus it should use rcu_barrier() on module unload. The rcu_barrier() is placed in mech.c ieee80211_stop_mesh() which is invoked from ieee80211_stop() in case vif.type == NL80211_IFTYPE_MESH_POINT. Signed-off-by: Jesper Dangaard Brouer <hawk@xxxxxxx> --- net/mac80211/mesh.c | 2 +- 1 files changed, 1 insertions(+), 1 deletions(-) diff --git a/net/mac80211/mesh.c b/net/mac80211/mesh.c index fc712e6..11cf45b 100644 --- a/net/mac80211/mesh.c +++ b/net/mac80211/mesh.c @@ -494,7 +494,7 @@ void ieee80211_stop_mesh(struct ieee80211_sub_if_data *sdata) * should it be using the interface and enqueuing * frames at this very time on another CPU. */ - synchronize_rcu(); + rcu_barrier(); /* Wait for RX path and call_rcu()'s */ skb_queue_purge(&sdata->u.mesh.skb_queue); } -- To unsubscribe from this list: send the line "unsubscribe linux-wireless" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
