Return-path: Received: from mail.atheros.com ([12.36.123.2]:39373 "EHLO mail.atheros.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752233AbYIKQuX (ORCPT ); Thu, 11 Sep 2008 12:50:23 -0400 Date: Thu, 11 Sep 2008 09:50:11 -0700 From: "Luis R. Rodriguez" To: Johannes Berg CC: Sujith Manoharan , John Linville , "linux-wireless@vger.kernel.org" Subject: Re: [PATCH 00/18] mac80211 cleanups and fixes Message-ID: <20080911165011.GA6049@tesla> (sfid-20080911_185028_074791_AD3BD971) References: <20080910220145.707263000@sipsolutions.net> <18632.55008.411078.289830@gargle.gargle.HOWL> <1221139351.6986.26.camel@johannes.berg> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" In-Reply-To: <1221139351.6986.26.camel@johannes.berg> Sender: linux-wireless-owner@vger.kernel.org List-ID: On Thu, Sep 11, 2008 at 06:22:31AM -0700, Johannes Berg wrote: > On Thu, 2008-09-11 at 13:59 +0530, Sujith wrote: > > > > I'd been talking with Sujith about this one: > > > > > > * mac80211: share STA information with driver > > > > > > and decided to just do it; as it stands it's not very useful > > > but I expect it to be used soon, if not we can remove the > > > EXPORT_SYMBOL again. > > > > > > > This would be very useful for ath9k. Making use of the > > private area for each STA can enable removal of the node list > > that is maintained currently. > > I had actually tried > (http://johannes.sipsolutions.net/patches/kernel/ath9k-sta-node.patch) > but you're using refcounting for the nodes while mac80211 RCU-protects > them, so I didn't get very far. Good thing I read RCU docs yesterday. We should be able to remove ref counts and simply use RCU and sychronize_rcu() before deletion. > It needs a bit more effort to make sure > you don't have node pointers stick around in some tx descriptor after > mac80211 decides to remove a node (which may very well happen while > frames are queued) We can call_rcu() here no, and let the driver deal with what it needs to prior to deletion? Luis