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=-5.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_MUTT autolearn=ham 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 68F49C04AB3 for ; Mon, 27 May 2019 14:05:22 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 48CFC205ED for ; Mon, 27 May 2019 14:05:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726583AbfE0OFV (ORCPT ); Mon, 27 May 2019 10:05:21 -0400 Received: from 8bytes.org ([81.169.241.247]:40248 "EHLO theia.8bytes.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726184AbfE0OFV (ORCPT ); Mon, 27 May 2019 10:05:21 -0400 Received: by theia.8bytes.org (Postfix, from userid 1000) id 6FB302E2; Mon, 27 May 2019 16:05:19 +0200 (CEST) Date: Mon, 27 May 2019 16:05:15 +0200 From: Joerg Roedel To: Lukasz Odzioba Cc: linux-kernel@vger.kernel.org, iommu@lists.linux-foundation.org, dwmw2@infradead.org, grzegorz.andrejczuk@intel.com Subject: Re: [PATCH 1/1] iommu/vt-d: Remove unnecessary rcu_read_locks Message-ID: <20190527140514.GE8420@8bytes.org> References: <1558359688-21804-1-git-send-email-lukasz.odzioba@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1558359688-21804-1-git-send-email-lukasz.odzioba@intel.com> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, May 20, 2019 at 03:41:28PM +0200, Lukasz Odzioba wrote: > We use RCU's for rarely updated lists like iommus, rmrr, atsr units. > > I'm not sure why domain_remove_dev_info() in domain_exit() was surrounded > by rcu_read_lock. Lock was present before refactoring in d160aca527, > but it was related to rcu list, not domain_remove_dev_info function. > > dmar_remove_one_dev_info() doesn't touch any of those lists, so it doesn't > require a lock. In fact it is called 6 times without it anyway. > > Fixes: d160aca5276d ("iommu/vt-d: Unify domain->iommu attach/detachment") > > Signed-off-by: Lukasz Odzioba Applied, thanks.