Return-path: Received: from mail-oi0-f67.google.com ([209.85.218.67]:42100 "EHLO mail-oi0-f67.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751049AbeERQru (ORCPT ); Fri, 18 May 2018 12:47:50 -0400 Received: by mail-oi0-f67.google.com with SMTP id t27-v6so7658385oij.9 for ; Fri, 18 May 2018 09:47:50 -0700 (PDT) Subject: Re: [PATCH] cfg80211: Fix support for flushing old scan results To: Johannes Berg , Tim Kourt Cc: linux-wireless@vger.kernel.org References: <20180511164835.40161-1-tim.a.kourt@linux.intel.com> <1526631206.3805.1.camel@sipsolutions.net> From: Denis Kenzior Message-ID: (sfid-20180518_184754_968558_C91347C2) Date: Fri, 18 May 2018 11:47:43 -0500 MIME-Version: 1.0 In-Reply-To: <1526631206.3805.1.camel@sipsolutions.net> Content-Type: text/plain; charset=utf-8; format=flowed Sender: linux-wireless-owner@vger.kernel.org List-ID: Hi Johannes, On 05/18/2018 03:13 AM, Johannes Berg wrote: > On Fri, 2018-05-11 at 09:48 -0700, Tim Kourt wrote: >> __cfg80211_bss_expire function was incorrectly used to flush the BSS >> entries from the previous scan results, causing NL80211_SCAN_FLAG_FLUSH >> flag to have no effect. > > Hmm. I guess I'm not convinced - what's the bug? > > We flush anything that's older than our start, so that should work just > fine? > Just FYI, there's definitely something funny with the scanning code: denkenz@iwd-test ~ $ sudo iw dev wlp2s0 scan flush BSS 10:c3:7b:54:74:d4(on wlp2s0) last seen: 274.815s [boottime] freq: 5765 beacon interval: 100 TUs signal: -35.00 dBm last seen: 349 ms ago Information elements from Probe Response frame: SSID: \x00\x00\x00\x00\x00\x00\x00\x00\x00 Then if I try: denkenz@iwd-test ~ $ sudo iw dev wlp2s0 scan flush ssid myssid BSS 10:c3:7b:54:74:d4(on wlp2s0) last seen: 319.667s [boottime] freq: 5765 beacon interval: 100 TUs signal: -42.00 dBm last seen: 350 ms ago Information elements from Probe Response frame: SSID: \x00\x00\x00\x00\x00\x00\x00\x00\x00 .... BSS 10:c3:7b:54:74:d4(on wlp2s0) last seen: 319.662s [boottime] freq: 5765 beacon interval: 100 TUs signal: -37.00 dBm last seen: 355 ms ago Information elements from Probe Response frame: SSID: myssid Shouldn't the second scan give a single result from that one BSS? Regards, -Denis