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=-4.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS 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 C7211C4363A for ; Tue, 27 Oct 2020 08:16:55 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6EBFD20878 for ; Tue, 27 Oct 2020 08:16:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1603786615; bh=RCUH66/doQOpFbMHVg40tupRCDHXXMCf0CikYNJvYJo=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=uS1l2tcTJZtFWeEjdM+8j2tRXw5zojeH+5Ib6zYVD03+/x2k+V8Y2Gn2JQWBz/2wj f8o9OKkr0KYQePMoMslEPYlaoFhv5KIbqtxMdvoO+Q7DMQLB+XIXFPxyCxi8dIpEYP 4c5DcjnKsZ+yQpQNdbm2Ru9t4wszxfRUnXAPpVkU= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2894526AbgJ0IQy (ORCPT ); Tue, 27 Oct 2020 04:16:54 -0400 Received: from mail-lj1-f195.google.com ([209.85.208.195]:35001 "EHLO mail-lj1-f195.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2894519AbgJ0IQy (ORCPT ); Tue, 27 Oct 2020 04:16:54 -0400 Received: by mail-lj1-f195.google.com with SMTP id x16so749409ljh.2; Tue, 27 Oct 2020 01:16:50 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=4X/i6x/+78+fLH0lPper9S35q82PCcSbtWfUqlievPc=; b=dFevk5ljJev2bT1xhviKxC52SYR6aPDG0fLcP1QG38OkfTom6xGNIM//0RZ/foJRP4 Ao4uapp0tLfheeZ7KT3I3J10TOuUGQMBiXCGnqilB4vtOf8WX4VVMAl0gr+Hxg/15OOz uz+HV2q/VNfHEgMLJ1fHZ0G26MoCZ/z0QXzcv9HXFrja/NZTHsFXVV3Bb+TjRKpyVAcs +G4kYFP0EOGv3frtkya2LMj4U5YTRkJlSbK9TFIWtiEi7TXpcAGZFrWO2/4K66IUWwMx HKKDf996qnl0iXgKrWL/N6GJ3X/YhTCHqL6Z//W3nD/cGpvWl/RahqO3zGiy/FNIdcVl LpLA== X-Gm-Message-State: AOAM531Rwf6a5ewZ5O/OLKRL2LUls8o3KiSvUKE9fLrVY32wEJhyp/3n qeEYvcVSTj7W2f3hLeBSzH8= X-Google-Smtp-Source: ABdhPJyiRzqsfEO4O7r5IIRQvb3+7LSAdAe3jrDZoAuW1ZpukGOup5MjnYT7Lif1P6AYdNpMCqJQUQ== X-Received: by 2002:a2e:8103:: with SMTP id d3mr545991ljg.384.1603786610328; Tue, 27 Oct 2020 01:16:50 -0700 (PDT) Received: from xi.terra (c-beaee455.07-184-6d6c6d4.bbcust.telenor.se. [85.228.174.190]) by smtp.gmail.com with ESMTPSA id v16sm92687lfq.68.2020.10.27.01.16.49 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 27 Oct 2020 01:16:49 -0700 (PDT) Received: from johan by xi.terra with local (Exim 4.93.0.4) (envelope-from ) id 1kXK9v-0001H7-Vf; Tue, 27 Oct 2020 09:16:48 +0100 Date: Tue, 27 Oct 2020 09:16:47 +0100 From: Johan Hovold To: Sebastian Andrzej Siewior Cc: Johan Hovold , Thomas Gleixner , LKML , Peter Zijlstra , "Ahmed S. Darwish" , Greg Kroah-Hartman , linux-usb@vger.kernel.org, Thomas Winischhofer , Mathias Nyman , Valentina Manea , Shuah Khan , Alan Stern , linux-omap@vger.kernel.org, Kukjin Kim , Krzysztof Kozlowski , linux-arm-kernel@lists.infradead.org, linux-samsung-soc@vger.kernel.org, Felipe Balbi , Duncan Sands Subject: Re: [patch V2 02/13] USB: serial: keyspan_pda: Replace in_interrupt() usage Message-ID: <20201027081647.GC4085@localhost> References: <20201019100629.419020859@linutronix.de> <20201019101109.753597069@linutronix.de> <20201025165647.GR26280@localhost> <20201026124753.btmdh3iwbwnff5dg@linutronix.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20201026124753.btmdh3iwbwnff5dg@linutronix.de> Precedence: bulk List-ID: X-Mailing-List: linux-omap@vger.kernel.org On Mon, Oct 26, 2020 at 01:47:53PM +0100, Sebastian Andrzej Siewior wrote: > On 2020-10-25 17:56:47 [+0100], Johan Hovold wrote: > > There's a ton of issues with this driver, but this is arguably making > > things worse. A line discipline may call write() from just about any > > context so we cannot rely on tty being non-NULL here (e.g. PPP). > > I wasn't aware of that. I've been looking at the callers each time a > `tty' was passed it looked like a preemptible context (due to mutex / > GFP_KERNEL) and so on. Yeah, the default line discipline only calls in preemptible context (these days), but others do not (e.g. see ppp_async_push()). Johan