Return-path: Received: from mail-ea0-f174.google.com ([209.85.215.174]:52475 "EHLO mail-ea0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752549AbaAVKYA convert rfc822-to-8bit (ORCPT ); Wed, 22 Jan 2014 05:24:00 -0500 Received: by mail-ea0-f174.google.com with SMTP id b10so4458124eae.33 for ; Wed, 22 Jan 2014 02:23:59 -0800 (PST) MIME-Version: 1.0 In-Reply-To: <1390384700.4334.24.camel@jlt4.sipsolutions.net> References: <1390228033-19162-1-git-send-email-michal.kazior@tieto.com> <1390228033-19162-3-git-send-email-michal.kazior@tieto.com> <1390318236.6199.45.camel@jlt4.sipsolutions.net> <1390381261.4334.12.camel@jlt4.sipsolutions.net> <1390384700.4334.24.camel@jlt4.sipsolutions.net> Date: Wed, 22 Jan 2014 11:23:58 +0100 Message-ID: (sfid-20140122_112404_236257_372CC6E4) Subject: Re: [PATCH 2/2] mac80211: implement multi-interface CSA From: Michal Kazior To: Johannes Berg Cc: linux-wireless , Luca Coelho Content-Type: text/plain; charset=UTF-8 Sender: linux-wireless-owner@vger.kernel.org List-ID: On 22 January 2014 10:58, Johannes Berg wrote: > On Wed, 2014-01-22 at 10:40 +0100, Michal Kazior wrote: >> > That's true, so maybe you just need to explain this chandef thing >> > better? I don't really see the utility (admittedly without actually >> > checking carefully in the code where you need it) >> >> Since you can CSA multiple interfaces you can have different chandefs >> for those interfaces. This means you need to know the chandef for the >> final channel switch. >> >> You could probably cache this to local->csa_chandef when processing >> the channel switch request itself, but that means you explicitly limit >> yourself to single CSA against a given hw/driver. >> >> At one point I was contemplating having a dedicated structure for >> channel switches, and have a list of channel switch structures in >> ieee80211_local, but perhaps that's just an overkill. > > But if we bind all interfaces against a 'pending' chanctx, then that's > all implicit in that chanctx calculating/binding, no? Correct. Hmm. How do you bind a pending chanctx? Does this mean an interface can have two channel contexts - the current one, and the pending one? I suppose you'd still need to iterate over interfaces (through local->interfaces or the [non-existent yet] chanctx->interfaces) anyway for validate/sanity check if the final switch is really okay, and/or possibly disconnect/stop some interfaces that didn't get a chance to request a channel switch (I'm thinking of your STA-CSA-GO case). Michał