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=-5.6 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 F0DA2C41604 for ; Sat, 3 Oct 2020 14:06:46 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9531C206C1 for ; Sat, 3 Oct 2020 14:06:46 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="vPOk1Eug" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1725787AbgJCOGq (ORCPT ); Sat, 3 Oct 2020 10:06:46 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46626 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725781AbgJCOGq (ORCPT ); Sat, 3 Oct 2020 10:06:46 -0400 Received: from mail-lf1-x142.google.com (mail-lf1-x142.google.com [IPv6:2a00:1450:4864:20::142]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 86A31C0613D0; Sat, 3 Oct 2020 07:06:45 -0700 (PDT) Received: by mail-lf1-x142.google.com with SMTP id d24so1453132lfa.8; Sat, 03 Oct 2020 07:06:45 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=subject:to:cc:references:from:message-id:date:user-agent :mime-version:in-reply-to:content-language:content-transfer-encoding; bh=Bx6Er5n5mhxYHHvURjb1uunhMDfSLBADFm1BcHlIQrU=; b=vPOk1EugRygidJMpN+/VQXyMhf/gszfPk2s+HuTMM/d0NvZr4eCvRaBuoUXqxf1AOG HAmoBdUOpTvTA1jk4DbOUJau1pIdx3pVwVuMJ7vAAgj+/P+R9aMi9lx5M58vCOHR6+Xk IvayIB8OANtfFY2sIPdem5LnyJNAQBjCJZuKmzt2lrWnUSl1l/GG4MDwKFws1Qg+DezI dDWVl98np/7r3xkKfIdVuTmxwbEB0/v0342grgnOyf+BNqQWUk+QCdFnlUH/WzfDCklS S97PqpcJ7+GWZiTnIjURp/iyM2aAjIGNQxmzjQOFuVIr4QEebB9FKxsXnMvS1UekcDsz xUxA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:cc:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=Bx6Er5n5mhxYHHvURjb1uunhMDfSLBADFm1BcHlIQrU=; b=ALdMtAlsp4fDrsFgE9mjr9BSK+VXaaByd9aqsNNY91c+4jboyyTp7VErwcVvqHzwQl TET+cuMmwdO93RTNLY2RzZylp3ByFbA+IX4IKXpptewjCfVX4XSb87fem8QtxNMsOgiB sPy9bDNUeX5Mrn19ZaZjcgnamK8Vk/LEMty4Co08/TpuZ3/v3/1wnl2HofrdNg4PKmt6 5krv/4dqokkx6bXS/Rafd+1S1LcITZmHCxPitMBVKt1xxjcUI9TPQIWN7UCHr+RdYPQJ 9c2j/Gu2+5ZRoGzcPARNsX87jUTjakal0RgUc39oX57039ZqzCpGWp1Kh91ZgmYZYP5v E1Dw== X-Gm-Message-State: AOAM531I+uKiOGbYGp8Wd7HthBh/ApOMpkN99CzvNuFz3m4LSIaZ1aGo b8284USEqrMjh/3eEd2Dz5Ij0/EFQNw= X-Google-Smtp-Source: ABdhPJzRjghQrvv/1QRYHrh7udF6gDxgv2wE+pcaClW4SpwZsyNRY8gl9G7Xb/voZ/Cb/jHHj5Yxhw== X-Received: by 2002:a19:2214:: with SMTP id i20mr2839812lfi.252.1601734003842; Sat, 03 Oct 2020 07:06:43 -0700 (PDT) Received: from [192.168.2.145] (109-252-91-252.nat.spd-mgts.ru. [109.252.91.252]) by smtp.googlemail.com with ESMTPSA id q17sm1518034lfd.37.2020.10.03.07.06.42 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Sat, 03 Oct 2020 07:06:43 -0700 (PDT) Subject: Re: [PATCH v5 2/3] iommu/tegra-smmu: Rework tegra_smmu_probe_device() To: Nicolin Chen , thierry.reding@gmail.com, joro@8bytes.org Cc: vdumpa@nvidia.com, jonathanh@nvidia.com, linux-tegra@vger.kernel.org, iommu@lists.linux-foundation.org, linux-kernel@vger.kernel.org References: <20201003065947.18671-1-nicoleotsuka@gmail.com> <20201003065947.18671-3-nicoleotsuka@gmail.com> From: Dmitry Osipenko Message-ID: <4a5a5b1c-080a-327a-1e2f-dc087948e1a1@gmail.com> Date: Sat, 3 Oct 2020 17:06:42 +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: <20201003065947.18671-3-nicoleotsuka@gmail.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-tegra@vger.kernel.org 03.10.2020 09:59, Nicolin Chen пишет: > static int tegra_smmu_of_xlate(struct device *dev, > struct of_phandle_args *args) > { > + struct platform_device *iommu_pdev = of_find_device_by_node(args->np); > + struct tegra_mc *mc = platform_get_drvdata(iommu_pdev); > u32 id = args->args[0]; > > + put_device(&iommu_pdev->dev); > + > + if (!mc || !mc->smmu) > + return -EPROBE_DEFER; I'm not very excited by seeing code in the patches that can't be explained by the patch authors and will appreciate if you could provide a detailed explanation about why this NULL checking is needed because I think it is unneeded, especially given that other IOMMU drivers don't have such check. I'm asking this question second time now, please don't ignore review comments next time. 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=-5.3 required=3.0 tests=BAYES_00,DKIM_ADSP_CUSTOM_MED, DKIM_INVALID,DKIM_SIGNED,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED,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 E85C0C41604 for ; Sat, 3 Oct 2020 14:06:50 +0000 (UTC) Received: from whitealder.osuosl.org (smtp1.osuosl.org [140.211.166.138]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 50856206C1 for ; Sat, 3 Oct 2020 14:06:50 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="vPOk1Eug" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 50856206C1 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=gmail.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=iommu-bounces@lists.linux-foundation.org Received: from localhost (localhost [127.0.0.1]) by whitealder.osuosl.org (Postfix) with ESMTP id D3AE9869FE; Sat, 3 Oct 2020 14:06:49 +0000 (UTC) X-Virus-Scanned: amavisd-new at osuosl.org Received: from whitealder.osuosl.org ([127.0.0.1]) by localhost (.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id 1WD0BeK1I5TK; Sat, 3 Oct 2020 14:06:49 +0000 (UTC) Received: from lists.linuxfoundation.org (lf-lists.osuosl.org [140.211.9.56]) by whitealder.osuosl.org (Postfix) with ESMTP id 44A28869DE; Sat, 3 Oct 2020 14:06:49 +0000 (UTC) Received: from lf-lists.osuosl.org (localhost [127.0.0.1]) by lists.linuxfoundation.org (Postfix) with ESMTP id 3093CC016F; Sat, 3 Oct 2020 14:06:49 +0000 (UTC) Received: from silver.osuosl.org (smtp3.osuosl.org [140.211.166.136]) by lists.linuxfoundation.org (Postfix) with ESMTP id 1406BC0051 for ; Sat, 3 Oct 2020 14:06:48 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by silver.osuosl.org (Postfix) with ESMTP id F2B6120377 for ; Sat, 3 Oct 2020 14:06:47 +0000 (UTC) X-Virus-Scanned: amavisd-new at osuosl.org Received: from silver.osuosl.org ([127.0.0.1]) by localhost (.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id 9FXx8jO-fPy6 for ; Sat, 3 Oct 2020 14:06:46 +0000 (UTC) X-Greylist: domain auto-whitelisted by SQLgrey-1.7.6 Received: from mail-lf1-f66.google.com (mail-lf1-f66.google.com [209.85.167.66]) by silver.osuosl.org (Postfix) with ESMTPS id B533D203F6 for ; Sat, 3 Oct 2020 14:06:45 +0000 (UTC) Received: by mail-lf1-f66.google.com with SMTP id 197so5398356lfo.11 for ; Sat, 03 Oct 2020 07:06:45 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=subject:to:cc:references:from:message-id:date:user-agent :mime-version:in-reply-to:content-language:content-transfer-encoding; bh=Bx6Er5n5mhxYHHvURjb1uunhMDfSLBADFm1BcHlIQrU=; b=vPOk1EugRygidJMpN+/VQXyMhf/gszfPk2s+HuTMM/d0NvZr4eCvRaBuoUXqxf1AOG HAmoBdUOpTvTA1jk4DbOUJau1pIdx3pVwVuMJ7vAAgj+/P+R9aMi9lx5M58vCOHR6+Xk IvayIB8OANtfFY2sIPdem5LnyJNAQBjCJZuKmzt2lrWnUSl1l/GG4MDwKFws1Qg+DezI dDWVl98np/7r3xkKfIdVuTmxwbEB0/v0342grgnOyf+BNqQWUk+QCdFnlUH/WzfDCklS S97PqpcJ7+GWZiTnIjURp/iyM2aAjIGNQxmzjQOFuVIr4QEebB9FKxsXnMvS1UekcDsz xUxA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:cc:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=Bx6Er5n5mhxYHHvURjb1uunhMDfSLBADFm1BcHlIQrU=; b=nHXMZadOe7h/7Yxt4+D0pscz/1B2Wt+WefqgEbnwBTLCaBfjk/q3qYfJ+JtJFBCxB0 tjrtY+uUszFSlbTrGX8z/xjBJ6nPyAtaHd+vW3S8SfLuuHNcBgcslVTeOzr+GJZrpRv/ VcgzfSIvTWi1NTTOvgjZpL63MjOwSHZvKWYLsRfIyvHpJSmm6/kfr+mF8c948Y4gCfaJ ZD2U1CqrhWD24wMQOPBzNb3YZNn+59XFJLeHEpAH6s985IFeFriQM8yeOtoKfsXUaa2H /Uy8RNQL860W7xRmbox9qOQA8KG2RYKwEbh8I/fU88wtCM/p/JKHcrkcfm2o1/XBw3ff s2Dg== X-Gm-Message-State: AOAM531e+2PYLXmYr0PXGcMEtWb7sScNeWcI1U9atOs0P0uIeAQJYDZR DGI0JlntjLjI+mvrMjJpPsA= X-Google-Smtp-Source: ABdhPJzRjghQrvv/1QRYHrh7udF6gDxgv2wE+pcaClW4SpwZsyNRY8gl9G7Xb/voZ/Cb/jHHj5Yxhw== X-Received: by 2002:a19:2214:: with SMTP id i20mr2839812lfi.252.1601734003842; Sat, 03 Oct 2020 07:06:43 -0700 (PDT) Received: from [192.168.2.145] (109-252-91-252.nat.spd-mgts.ru. [109.252.91.252]) by smtp.googlemail.com with ESMTPSA id q17sm1518034lfd.37.2020.10.03.07.06.42 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Sat, 03 Oct 2020 07:06:43 -0700 (PDT) Subject: Re: [PATCH v5 2/3] iommu/tegra-smmu: Rework tegra_smmu_probe_device() To: Nicolin Chen , thierry.reding@gmail.com, joro@8bytes.org References: <20201003065947.18671-1-nicoleotsuka@gmail.com> <20201003065947.18671-3-nicoleotsuka@gmail.com> From: Dmitry Osipenko Message-ID: <4a5a5b1c-080a-327a-1e2f-dc087948e1a1@gmail.com> Date: Sat, 3 Oct 2020 17:06:42 +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: <20201003065947.18671-3-nicoleotsuka@gmail.com> Content-Language: en-US Cc: linux-tegra@vger.kernel.org, linux-kernel@vger.kernel.org, iommu@lists.linux-foundation.org, jonathanh@nvidia.com X-BeenThere: iommu@lists.linux-foundation.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: Development issues for Linux IOMMU support List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: base64 Errors-To: iommu-bounces@lists.linux-foundation.org Sender: "iommu" MDMuMTAuMjAyMCAwOTo1OSwgTmljb2xpbiBDaGVuINC/0LjRiNC10YI6Cj4gIHN0YXRpYyBpbnQg dGVncmFfc21tdV9vZl94bGF0ZShzdHJ1Y3QgZGV2aWNlICpkZXYsCj4gIAkJCSAgICAgICBzdHJ1 Y3Qgb2ZfcGhhbmRsZV9hcmdzICphcmdzKQo+ICB7Cj4gKwlzdHJ1Y3QgcGxhdGZvcm1fZGV2aWNl ICppb21tdV9wZGV2ID0gb2ZfZmluZF9kZXZpY2VfYnlfbm9kZShhcmdzLT5ucCk7Cj4gKwlzdHJ1 Y3QgdGVncmFfbWMgKm1jID0gcGxhdGZvcm1fZ2V0X2RydmRhdGEoaW9tbXVfcGRldik7Cj4gIAl1 MzIgaWQgPSBhcmdzLT5hcmdzWzBdOwo+ICAKPiArCXB1dF9kZXZpY2UoJmlvbW11X3BkZXYtPmRl dik7Cj4gKwo+ICsJaWYgKCFtYyB8fCAhbWMtPnNtbXUpCj4gKwkJcmV0dXJuIC1FUFJPQkVfREVG RVI7CgpJJ20gbm90IHZlcnkgZXhjaXRlZCBieSBzZWVpbmcgY29kZSBpbiB0aGUgcGF0Y2hlcyB0 aGF0IGNhbid0IGJlCmV4cGxhaW5lZCBieSB0aGUgcGF0Y2ggYXV0aG9ycyBhbmQgd2lsbCBhcHBy ZWNpYXRlIGlmIHlvdSBjb3VsZCBwcm92aWRlCmEgZGV0YWlsZWQgZXhwbGFuYXRpb24gYWJvdXQg d2h5IHRoaXMgTlVMTCBjaGVja2luZyBpcyBuZWVkZWQgYmVjYXVzZSBJCnRoaW5rIGl0IGlzIHVu bmVlZGVkLCBlc3BlY2lhbGx5IGdpdmVuIHRoYXQgb3RoZXIgSU9NTVUgZHJpdmVycyBkb24ndApo YXZlIHN1Y2ggY2hlY2suCgpJJ20gYXNraW5nIHRoaXMgcXVlc3Rpb24gc2Vjb25kIHRpbWUgbm93 LCBwbGVhc2UgZG9uJ3QgaWdub3JlIHJldmlldwpjb21tZW50cyBuZXh0IHRpbWUuCl9fX19fX19f X19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fX19fCmlvbW11IG1haWxpbmcgbGlz dAppb21tdUBsaXN0cy5saW51eC1mb3VuZGF0aW9uLm9yZwpodHRwczovL2xpc3RzLmxpbnV4Zm91 bmRhdGlvbi5vcmcvbWFpbG1hbi9saXN0aW5mby9pb21tdQ==