From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from out-178.mta0.migadu.com (out-178.mta0.migadu.com [91.218.175.178]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 0294433A9F0 for ; Wed, 28 Jan 2026 08:53:45 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=91.218.175.178 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1769590429; cv=none; b=MI6/VSmVmeKk9W9mLPKOBgcKVtPnYnCKibCeGMRbRNJH0E1T8Y9oTAHOkbcw5SLIjEjzN5RRyVf7bQSPvXgGl4rICE8Hd6oZiH2pCmS1TsRi2JSBrVoHe3JIcCElZ1TezUPnnrqzl99bo+pE4/KhWqagxvGTaHpSeuFZ9EgXsMA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1769590429; c=relaxed/simple; bh=5m7J5rDw9WY2h4fLSz7rRDf6IUclfItjW+xf93dPY6c=; h=Content-Type:From:Mime-Version:Subject:Date:Message-Id:References: Cc:In-Reply-To:To; b=F0QQXbNWd0bEM+bWmZECrOg/R/GIVlpFu7zEv53dA1R+84vsUCJs82CEiKXuGJ+y156DWBroy4lvwTDhnFKqHJpInbpDZUbwDDtnvpGZ3evq9cd2WFrg5CUhwSFTC0suSgZ0D3c6Y22OMAS7a8e82x7k975Xyqc9P7qrSaZegsg= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev; spf=pass smtp.mailfrom=linux.dev; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b=cP01htQL; arc=none smtp.client-ip=91.218.175.178 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.dev Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b="cP01htQL" Content-Type: text/plain; charset=utf-8 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1769590422; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=5m7J5rDw9WY2h4fLSz7rRDf6IUclfItjW+xf93dPY6c=; b=cP01htQLonr9ql3iusuwyORkcSoYe16/u7G2bg2tQdukMeqmMcW0McRBB02DCgEblGZcPi hYuNpRZ9bvFYVUVYW5zdvr8KDLCUNF08AkJ68795fqNul4Vq4VRAM72wfIstRZU0pbbxdF XkdzeRzUvIrmqrDQq/0YVNv+By/xrKQ= Content-Transfer-Encoding: quoted-printable X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. From: Matthew Schwartz Precedence: bulk X-Mailing-List: linux-wireless@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 (1.0) Subject: Re: Clarification on the usage of NL80211_SCAN_FLAG_FLUSH Date: Wed, 28 Jan 2026 00:53:28 -0800 Message-Id: References: Cc: linux-wireless@vger.kernel.org In-Reply-To: To: Johannes Berg X-Migadu-Flow: FLOW_OUT > On Jan 28, 2026, at 12:39=E2=80=AFAM, Johannes Berg wrote: >=20 > =EF=BB=BFHi, >=20 >> Is this intended behavior of NL80211_SCAN_FLAG_FLUSH where it clears all B= SS entries regardless of which channels were scanned, or should NL80211_SCAN= _FLAG_FLUSH be limited to channels that were scanned in the request which tr= iggered them? The uAPI definition for it is simply "flush cache before scann= ing", but this seems open to interpretation as to whether it means the entir= e cache or just the cache on scanned channels. >=20 > Well, AFAICT it has always done that, and so I think regardless of what > might have been the original intent, it simply is that behaviour now. > Changing it in the kernel would just end up having to fix two places, > unless you somehow don't care about running on older kernels without > fixes. >=20 > I also tend to think it makes sense since the scan could, at least in > theory, do e.g. colocated scanning, so networks on channels other than > the ones explicitly listed could be discovered. Trying to do anything > other than "flush all" would be far more complex. Okay, thanks for the clarification. I=E2=80=99ll try and take a look at how i= wd is using the flush then because it seems like it=E2=80=99s overusing it, o= r maybe needs some other logic to prevent the connection issues. Thanks, Matt >=20 > johannes