From nobody Thu Sep 11 18:24:14 2025 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 E3737C05027 for ; Fri, 17 Feb 2023 09:56:36 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230269AbjBQJ4e (ORCPT ); Fri, 17 Feb 2023 04:56:34 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49232 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230236AbjBQJ42 (ORCPT ); Fri, 17 Feb 2023 04:56:28 -0500 Received: from mga14.intel.com (mga14.intel.com [192.55.52.115]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 360A963BC5 for ; Fri, 17 Feb 2023 01:56:21 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1676627781; x=1708163781; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=I7zwcHhE0QciS3+BHxkcRCwFeb6U9lVqL1VaFiFdxu8=; b=lODVbbV86Eq4xmxpCfRYhX8gfMppxZYG+8M2uXP4sOyaaOZvn8rFXELX kNwKFfSwVYQGldFw3sBQbUMjAv+Xv6lCSSKoElinWHIN774f0ed7IlVKL Z+w1bqAhGlPcsV/00GRftlii3BYgbp6cveWFcMm5bbHuOVFyNf2IQdjBg U0pux6QPhg44ybPNdB0TCHikeNCuR0Sntxl5RckCehwosVhpyqY83r3DE MeyQYhw9bRZoX0sKJgOakvz8q0fdYzyWHZExREHRyELIHGSZykV4jNcR2 k98F+6SpY5j64gjOlRLH1qZbPR9bfkR8V0RFg6xmx+johxEO7Md5xJriS Q==; X-IronPort-AV: E=McAfee;i="6500,9779,10623"; a="331955258" X-IronPort-AV: E=Sophos;i="5.97,304,1669104000"; d="scan'208";a="331955258" Received: from fmsmga005.fm.intel.com ([10.253.24.32]) by fmsmga103.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 17 Feb 2023 01:56:17 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6500,9779,10623"; a="999391230" X-IronPort-AV: E=Sophos;i="5.97,304,1669104000"; d="scan'208";a="999391230" Received: from allen-box.sh.intel.com ([10.239.159.48]) by fmsmga005.fm.intel.com with ESMTP; 17 Feb 2023 01:56:15 -0800 From: Lu Baolu To: iommu@lists.linux.dev Cc: Joerg Roedel , Jason Gunthorpe , Christoph Hellwig , Kevin Tian , Will Deacon , Robin Murphy , linux-kernel@vger.kernel.org, Lu Baolu Subject: [PATCH v2 4/6] iommu: Move lock from iommu_change_dev_def_domain() to its caller Date: Fri, 17 Feb 2023 17:47:34 +0800 Message-Id: <20230217094736.159005-5-baolu.lu@linux.intel.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20230217094736.159005-1-baolu.lu@linux.intel.com> References: <20230217094736.159005-1-baolu.lu@linux.intel.com> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Type: text/plain; charset="utf-8" The intention is to make it possible to put group ownership check and default domain change in a same critical region protected by the group's mutex lock. No intentional functional change. Signed-off-by: Lu Baolu --- drivers/iommu/iommu.c | 29 ++++++++++++++--------------- 1 file changed, 14 insertions(+), 15 deletions(-) diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c index 093692308b80..e1ae1eb4faf0 100644 --- a/drivers/iommu/iommu.c +++ b/drivers/iommu/iommu.c @@ -2892,7 +2892,7 @@ static int iommu_change_dev_def_domain(struct iommu_g= roup *group, int ret, dev_def_dom; struct device *dev; =20 - mutex_lock(&group->mutex); + lockdep_assert_held(&group->mutex); =20 if (group->default_domain !=3D group->domain) { dev_err_ratelimited(prev_dev, "Group not assigned to default domain\n"); @@ -2980,28 +2980,15 @@ static int iommu_change_dev_def_domain(struct iommu= _group *group, goto free_new_domain; =20 group->domain =3D group->default_domain; - - /* - * Release the mutex here because ops->probe_finalize() call-back of - * some vendor IOMMU drivers calls arm_iommu_attach_device() which - * in-turn might call back into IOMMU core code, where it tries to take - * group->mutex, resulting in a deadlock. - */ - mutex_unlock(&group->mutex); - - /* Make sure dma_ops is appropriatley set */ - iommu_group_do_probe_finalize(dev, group->default_domain); iommu_domain_free(prev_dom); + return 0; =20 free_new_domain: iommu_domain_free(group->default_domain); group->default_domain =3D prev_dom; group->domain =3D prev_dom; - out: - mutex_unlock(&group->mutex); - return ret; } =20 @@ -3089,7 +3076,19 @@ static ssize_t iommu_group_store_type(struct iommu_g= roup *group, goto out; } =20 + mutex_lock(&group->mutex); ret =3D iommu_change_dev_def_domain(group, dev, req_type); + /* + * Release the mutex here because ops->probe_finalize() call-back of + * some vendor IOMMU drivers calls arm_iommu_attach_device() which + * in-turn might call back into IOMMU core code, where it tries to take + * group->mutex, resulting in a deadlock. + */ + mutex_unlock(&group->mutex); + + /* Make sure dma_ops is appropriatley set */ + if (!ret) + iommu_group_do_probe_finalize(dev, group->default_domain); ret =3D ret ?: count; =20 out: --=20 2.34.1