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 DDC13C433EF for ; Tue, 14 Jun 2022 07:22:57 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1354123AbiFNHW4 (ORCPT ); Tue, 14 Jun 2022 03:22:56 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37130 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1352454AbiFNHWw (ORCPT ); Tue, 14 Jun 2022 03:22:52 -0400 Received: from mga09.intel.com (mga09.intel.com [134.134.136.24]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id EA7EB2A400 for ; Tue, 14 Jun 2022 00:22:50 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1655191370; x=1686727370; h=message-id:date:mime-version:cc:subject:to:references: from:in-reply-to:content-transfer-encoding; bh=CzvGOqm3s1ZUzeSM0+qcKhIjvYujoS+oprriCQFDToU=; b=VciUY2lwZxMFqUwB9MhOSdfbR/oa+vfuiza3Goc+Fn37NxLiPs7wHXE+ a+Ww4a5jtnMwJW7TdMgwTWhjZtu9WC7PMHux3Gbi5WWFekyGYCRW+Vewo ux9yGLLdMLkjlRF0HnzmFJSWIEuYiPeiT4lnKvWXNfetbVXe72LfjySpP X8qk4n80W+Rk6XvQZMJzzcVy2Jkwgy8GJok0jSImI/scu/sW92ksAQbEU P3y66BR/8jh69/BjM3NDUXrvR8drMMrQdFMVRtJTURRl7hr2pBdOLjBm1 HdIIWR27YQgW7DOnMjChubP8W76h/tS3OwjqG4nPhJitRPxXptM6ye2GS Q==; X-IronPort-AV: E=McAfee;i="6400,9594,10377"; a="279253521" X-IronPort-AV: E=Sophos;i="5.91,299,1647327600"; d="scan'208";a="279253521" Received: from fmsmga005.fm.intel.com ([10.253.24.32]) by orsmga102.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 14 Jun 2022 00:22:50 -0700 X-IronPort-AV: E=Sophos;i="5.91,299,1647327600"; d="scan'208";a="910837669" Received: from gren5-mobl1.ccr.corp.intel.com (HELO [10.255.29.39]) ([10.255.29.39]) by fmsmga005-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 14 Jun 2022 00:22:47 -0700 Message-ID: Date: Tue, 14 Jun 2022 15:22:46 +0800 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.9.1 Cc: baolu.lu@linux.intel.com, Will Deacon , Robin Murphy , "Liu, Yi L" , "Pan, Jacob jun" , "iommu@lists.linux-foundation.org" , "linux-kernel@vger.kernel.org" Subject: Re: [PATCH v2 06/12] iommu/vt-d: Acquiring lock in domain ID allocation helpers Content-Language: en-US To: "Tian, Kevin" , Joerg Roedel , "Raj, Ashok" , Christoph Hellwig , Jason Gunthorpe References: <20220614025137.1632762-1-baolu.lu@linux.intel.com> <20220614025137.1632762-7-baolu.lu@linux.intel.com> From: Baolu Lu In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 2022/6/14 14:52, Tian, Kevin wrote: >> From: Lu Baolu >> Sent: Tuesday, June 14, 2022 10:52 AM >> >> The iommu->lock is used to protect the per-IOMMU domain ID resource. >> Moving the lock into the ID alloc/free helpers makes the code more >> compact. At the same time, the device_domain_lock is irrelevant to >> the domain ID resource, remove its assertion as well. >> >> On the other hand, the iommu->lock is never used in interrupt context, >> there's no need to use the irqsave variant of the spinlock calls. > > I still prefer to separating reduction of lock ranges from changing irqsave. > Locking is tricky. From bisect p.o.v. it will be a lot easier if we just change > one logic in one patch. > Fair enough. I will do this in the next version. Best regards, baolu