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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id DAF42C433FE for ; Tue, 3 May 2022 07:50:26 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232503AbiECHxz (ORCPT ); Tue, 3 May 2022 03:53:55 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:32786 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232519AbiECHxw (ORCPT ); Tue, 3 May 2022 03:53:52 -0400 Received: from mail-ed1-x52a.google.com (mail-ed1-x52a.google.com [IPv6:2a00:1450:4864:20::52a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6E16B2BF3 for ; Tue, 3 May 2022 00:50:20 -0700 (PDT) Received: by mail-ed1-x52a.google.com with SMTP id t5so8318636edw.11 for ; Tue, 03 May 2022 00:50:20 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=wp+HuhCzVQcbpzvT/sQrzmDjeIdh00lZI9oDxB6WyTs=; b=MaRFzGoMD1a278grMU14/yYlEhePHu15Lav8QNQrQHkccVbXPqgmvM1VFUtuC9Fjf4 uJ3Rgbif7K6L8Ar8zRmKbftuhHKSa1UQ3SwebB9FJsDSmAGIbAM/w9B4Pma+MsXx73Av tBlw/wqeYyPZWnubeZzUsmbpdMPm/M0Fs/b6h3BmrufAJfacj89ELyGunz7ZfLR4dbcQ 8fzP9L7Ut+fKZrCPOpNjXsoKndESVxRp91TmVHnheF4t6Z5QCcAfvoUrYdJaBATgzHK4 L7wiHAO+Kbyg/3nyOqSVZr5kgTn+lepmUGIj3npYWsgp9O3lwfGl0Qx957ysvk/ZK+xQ ksgA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:date:from:to:cc:subject:message-id:references :mime-version:content-disposition:in-reply-to; bh=wp+HuhCzVQcbpzvT/sQrzmDjeIdh00lZI9oDxB6WyTs=; b=WLv+2Y9PrPJ2x0Cbl/1fSdPwz3JbysVBu82OX/slK4bLzLDX/hWkk3leSFOf+G/F4d SATsKcEBVwydJXX7LpN/UCZic9fEmfHkYWsjRitDLkh9vstZ2lmo2wBwXGJvrCf8sH5+ 6G+d0oRKhs7F7bdbw2idQSrod7LQLH/G8ZzbXHA/mRGD/+3rgNSGW6u/yk55ILMrSLDX QyrHCe/wCc0HYHqYiPCXRKl7jvKHx0vhFTLNkO/CB69AAV335gHlFdljWcsZgGZJzuoC 4TbasBliQ2DLo5heBJYskzWC/qtYfVMScoCmDHItsIfUP//o0rMzWGWWhjbg5PclRLtH 0tSA== X-Gm-Message-State: AOAM531XnncA5nZA2OlmOH439+Y83c+ICUpUrYQGaohE1AUFF+fstIrH YH8k35TkQtQezyXRimlM2loZxw== X-Google-Smtp-Source: ABdhPJyVyq4b/kVlB63u3UarpBNZnJKtF6IDLyaW7pS64uWqHVVg2cH/YhsdXpfIKhYgli0kY9qkQw== X-Received: by 2002:a50:f1c5:0:b0:425:dd04:b7a9 with SMTP id y5-20020a50f1c5000000b00425dd04b7a9mr16790672edl.388.1651564218903; Tue, 03 May 2022 00:50:18 -0700 (PDT) Received: from myrica (cpc92880-cmbg19-2-0-cust679.5-4.cable.virginm.net. [82.27.106.168]) by smtp.gmail.com with ESMTPSA id cw27-20020a056402229b00b0042617ba6387sm7464883edb.17.2022.05.03.00.50.16 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 03 May 2022 00:50:18 -0700 (PDT) Date: Tue, 3 May 2022 08:49:52 +0100 From: Jean-Philippe Brucker To: Baolu Lu Cc: Fenghua Yu , Dave Hansen , Tony Luck , Ashok Raj , Ravi V Shankar , Peter Zijlstra , robin.murphy@arm.com, Dave Hansen , x86 , linux-kernel , iommu , Ingo Molnar , Borislav Petkov , Andy Lutomirski , Josh Poimboeuf , zhangfei.gao@linaro.org, Thomas Gleixner , will@kernel.org Subject: Re: [PATCH v4 05/11] iommu/sva: Assign a PASID to mm on PASID allocation and free it on mm exit Message-ID: References: <8c044e49-74bb-df56-8a60-663013c0910e@intel.com> <63582490-a794-fd11-0380-44b27cc660b7@intel.com> <044595e6-e5d0-26c2-af8e-fc9d06906179@linux.intel.com> <3ea91623-97ea-f318-70db-55f08922d7ce@linux.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <3ea91623-97ea-f318-70db-55f08922d7ce@linux.intel.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, Apr 30, 2022 at 03:33:17PM +0800, Baolu Lu wrote: > Jean, another quick question about the iommu_sva_bind_device() > > /** > * iommu_sva_bind_device() - Bind a process address space to a device > * @dev: the device > * @mm: the mm to bind, caller must hold a reference to it > * @drvdata: opaque data pointer to pass to bind callback > > This interface requires the caller to take a reference to mm. Which > reference should it take, mm->mm_count or mm->mm_users? It's better to > make it explicit in this comment. Agreed, it's mm_users as required by mmu_notifier_register() Thanks, Jean