From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-2.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_2 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id BDECFC742B1 for ; Fri, 12 Jul 2019 09:40:16 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 92E312064B for ; Fri, 12 Jul 2019 09:40:16 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726605AbfGLJkP (ORCPT ); Fri, 12 Jul 2019 05:40:15 -0400 Received: from s3.sipsolutions.net ([144.76.43.62]:55792 "EHLO sipsolutions.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725989AbfGLJkP (ORCPT ); Fri, 12 Jul 2019 05:40:15 -0400 Received: by sipsolutions.net with esmtpsa (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1hls2H-00077E-4Y; Fri, 12 Jul 2019 11:40:13 +0200 Message-ID: <43055be7b2d7ff0f8dbadd19443fc73f30f93bb6.camel@sipsolutions.net> Subject: Re: [RFC PATCH v3 0/2] cfg80211: fix duplicated scan entries after channel switch From: Johannes Berg To: Sergey Matyukevich Cc: "linux-wireless@vger.kernel.org" , Igor Mitsyanko , Mikhail Karpenko Date: Fri, 12 Jul 2019 11:40:11 +0200 In-Reply-To: <20190712092716.ywnkns473s5rtoku@bars> References: <20190710173651.15770-1-sergey.matyukevich.os@quantenna.com> <1c371a5921200a11da459b591df121bbcb0f967d.camel@sipsolutions.net> <20190712092716.ywnkns473s5rtoku@bars> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.28.5 (3.28.5-3.fc28) Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-wireless-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-wireless@vger.kernel.org On Fri, 2019-07-12 at 09:27 +0000, Sergey Matyukevich wrote: > On Fri, Jul 12, 2019 at 11:11:19AM +0200, Johannes Berg wrote: > > > > [External Email]: This email arrived from an external source - Please exercise caution when opening any attachments or clicking on links. Heh, you have a not so fun email system that rewrites mails ... > > > Suggested approach to handle non-transmitting BSS entries is simplified in the > > > following sense. If new entries have been already created after channel switch, > > > only transmitting bss will be updated using IEs of new entry for the same > > > transmitting bss. Non-transmitting bss entries will be updated as soon as > > > new mgmt frames are received. Updating non-transmitting bss entries seems > > > too expensive: nested nontrans_list traversing is needed since we can not > > > rely on the same order of old and new non-transmitting entries. > > > > That sounds like a reasonable trade-off. I do wonder though what happens > > if we're connected to a non-transmitting BSS? > > Well, here I rely upon the assumption that CSA IEs of non-transmitting BSS > are handled correctly by mac80211 or any FullMAC firmware. And if we are > connected to non-transmitting BSS rather than transmitting one, the > following code in the beginning of new cfg80211_update_assoc_bss_entry > function is supposed to care about this use-case: Right, it will be updated on RX. But then if we chanswitch, we would probably (mac80211 using a pointer to the non-transmitting BSS) update only one of the nontransmitting BSSes? Just saying that maybe we need to be careful there - or your wording might be incorrect. We might end up updating a *nontransmitting* BSS, and then its transmitting/other non-tx ones only later? johannes