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=-7.5 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE, SPF_PASS,USER_AGENT_SANE_1 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 8812EC433E2 for ; Tue, 1 Sep 2020 18:56:44 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 5AC6A2065F for ; Tue, 1 Sep 2020 18:56:44 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="tVRoeQwB" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732579AbgIAS4n (ORCPT ); Tue, 1 Sep 2020 14:56:43 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57976 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731566AbgIAS4Z (ORCPT ); Tue, 1 Sep 2020 14:56:25 -0400 Received: from mail-lf1-x144.google.com (mail-lf1-x144.google.com [IPv6:2a00:1450:4864:20::144]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 11949C061244; Tue, 1 Sep 2020 11:56:25 -0700 (PDT) Received: by mail-lf1-x144.google.com with SMTP id y2so1379503lfy.10; Tue, 01 Sep 2020 11:56:24 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=subject:from:to:cc:references:message-id:date:user-agent :mime-version:in-reply-to:content-language:content-transfer-encoding; bh=G85PUm7a3EZzS/FYnNEVI0eznDTH8pPJcc+osLm7WqY=; b=tVRoeQwB/gWeuJVETgIoI6uDSLBu9Oi18EgggfK6uMO6UdxaRljqsV964YZWadqrUD gnqR/AUlD1T/UL2fXjhcB4us5pytm/ub02fZv4t79xOsyGD7v2OKOonJB1hxTlohcn/b 3SL21pqUtnNXQs4+7+oouQ2Ppzio4eXKbbvGhuujsuUCRBRioI75eRg/okkBcUhbEPXT Wb1CQfA3E//DU2JpFZteOvIezkrUmhiGht8sT2mEGv4iAMtCcwm76LuMvZO0fb6Dv1V/ jScuFD/qzzG4zSH31l/chlaXN3QgEuoeBbsGZBYjbVRN9Hxo17lJ2aY1WoAw1VrY0L6M GiBg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:from:to:cc:references:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=G85PUm7a3EZzS/FYnNEVI0eznDTH8pPJcc+osLm7WqY=; b=RJC9J7ogCFEv8GMgyeZ913sFscxuqelQjVKtRHYo7YittwUVmNRKCUHOLaTF0kceu4 2zkitXYaZAkCBEOUeP0OWJyGibM7zyy+pgONjKXTxtYyKIBSan3sg+jkuQp6WTQNFACZ KSuOO4K2BycPLDK4KopZedM5JD+qgOO5EbznYJwc6s5y9xzGPUjRI3eHJbodumxQ4/hT Gz6KSxB7FN5vx65OMvAueSsFYBXeJWvyhtbDTnlD4JXUEQrEoWlp9zWXtk4cg/Aepvlc IHZ/T3e4ADzPyUyMBw1o5rjAdU///D+OyWm4V01k+ouTR799bxUaO2oMC8ESsuSxFWxc HFUQ== X-Gm-Message-State: AOAM531un6BGW7OgJTJR0Zrf+tORPIASHZGJwMBu+/XD0edyn/JsVYdL 4tL4CsBpH7rsIUXkYKCtA1Bhn7es1X8= X-Google-Smtp-Source: ABdhPJytkMxC+QnEFyPCwOzPuvfcWYWQYoBFmyrc6f5aTlvzcgsyU7pjMfTvbqXAGKvX8ZR5PgQIPg== X-Received: by 2002:a19:447:: with SMTP id 68mr1387400lfe.26.1598986583325; Tue, 01 Sep 2020 11:56:23 -0700 (PDT) Received: from [192.168.2.145] (109-252-170-211.dynamic.spd-mgts.ru. [109.252.170.211]) by smtp.googlemail.com with ESMTPSA id 10sm468433lfq.64.2020.09.01.11.56.22 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 01 Sep 2020 11:56:22 -0700 (PDT) Subject: Re: [PATCH v4] iommu/tegra-smmu: Add locking around mapping operations From: Dmitry Osipenko To: Thierry Reding , Joerg Roedel , Jonathan Hunter , Krishna Reddy Cc: iommu@lists.linux-foundation.org, linux-tegra@vger.kernel.org, linux-kernel@vger.kernel.org References: <20200901171305.6929-1-digetx@gmail.com> Message-ID: <2d38fcab-bc7a-2986-ff39-9403164914e4@gmail.com> Date: Tue, 1 Sep 2020 21:56:21 +0300 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: <20200901171305.6929-1-digetx@gmail.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 01.09.2020 20:13, Dmitry Osipenko пишет: ... > + /* > + * In order to prevent exhaustion of the atomic memory pool, we > + * allocate page in a sleeping context if GFP flags permit. Hence > + * spinlock needs to be unlocked and re-locked after allocation. > + */ > + if (!(gfp & GFP_NOWAIT)) > + spin_unlock_irqrestore(&as->lock, *flags); > + > + page = alloc_page(gfp | __GFP_DMA | __GFP_ZERO); > + > + if (!(gfp & GFP_NOWAIT)) > + spin_lock_irqsave(&as->lock, *flags); I realized that GFP_NOWAIT is a wrong flag to check here once I saw warnings about sleeping in atomic context. Apparently __GFP_ATOMIC should be used instead, I'll make v5.