From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from smtp.codeaurora.org ([198.145.29.96]:45532 "EHLO smtp.codeaurora.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751852AbdGDOKm (ORCPT ); Tue, 4 Jul 2017 10:10:42 -0400 From: Kalle Valo To: Brian Norris Cc: Johannes Berg , Ganapathi Bhat , Nishant Sarmukadam , linux-kernel@vger.kernel.org, Dmitry Torokhov , Amitkumar Karwar , linux-wireless@vger.kernel.org Subject: Re: [PATCH 05/14] mwifiex: re-register wiphy across reset References: <20170525001119.64791-1-briannorris@chromium.org> <20170525001119.64791-5-briannorris@chromium.org> <87fufk2hmm.fsf@purkki.adurom.net> <20170601173954.GA138807@google.com> <87inka77md.fsf@codeaurora.org> <1496999018.2424.5.camel@sipsolutions.net> <20170621182706.GB92340@google.com> <1498136554.2246.9.camel@sipsolutions.net> <20170627204858.GB93674@google.com> Date: Tue, 04 Jul 2017 17:10:24 +0300 In-Reply-To: <20170627204858.GB93674@google.com> (Brian Norris's message of "Tue, 27 Jun 2017 13:48:59 -0700") Message-ID: <87podgi97z.fsf@kamboji.qca.qualcomm.com> (sfid-20170704_161105_261969_1DE0E3A4) MIME-Version: 1.0 Content-Type: text/plain Sender: linux-wireless-owner@vger.kernel.org List-ID: (I was on vacation and inbox exploded again) Brian Norris writes: > On Thu, Jun 22, 2017 at 03:02:34PM +0200, Johannes Berg wrote: >> On Wed, 2017-06-21 at 11:27 -0700, Brian Norris wrote: > >> > > Without checking the code now, it seems entirely plausible that >> > > this is >> > > holding some lock that would lock out the control path entirely, >> > > for >> > > the duration until the wiphy is actually unregistered? >> > > >> > > Actually, you can't unregister with the relevant locks held >> > > (without >> > > causing deadlocks), so perhaps it's marking the wiphy as >> > > unavailable so >> > > that all operations fail? >> > >> > One of the above two sounds along the right line. But it's something >> > I couldn't really figure out how to do quite right. >> > >> > Dumb question: how would I mark the wiphy as unavailable? Is there >> > something I can do at the cfg80211 level? Or would I really have to >> > guard all the cfg80211 entry points into mwifiex with a flag or lock? >> >> There isn't really a good way to do this. You can, of course, call >> wiphy_unregister(), but if you could do that you'd already have the >> problem solved, I think? > > That's probably along the right track. There are still some things we'd > need to do properly before that though, and this is where all the > problems are so far. (Also, this is what Kalle was already objecting to; > he didn't think we should be unregistering/recreating the wiphy, but I > think he ended up softening on that a bit.) Just to clarify I was more like hoping there would be a better way to do it, not really objecting the current method, but I didn't realise that of course it's harder to do a transparent firmware restart with fullmac design. And certainly what are you doing now is much much better than doing nothing after a firmware crash. -- Kalle Valo