From nobody Thu Sep 11 18:24:15 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 90415C636D4 for ; Fri, 17 Feb 2023 09:56:21 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230195AbjBQJ4T (ORCPT ); Fri, 17 Feb 2023 04:56:19 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48982 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230004AbjBQJ4N (ORCPT ); Fri, 17 Feb 2023 04:56:13 -0500 Received: from mga14.intel.com (mga14.intel.com [192.55.52.115]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 371425F82B for ; Fri, 17 Feb 2023 01:56:13 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1676627773; x=1708163773; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=soshgH1no5hycuBrP/dpzD8rbmx7eoXwNiXBGFJYNPk=; b=GsHYdIRbjYiVUumDzC3kI9t05iLXB+kWd30OPADqvqsc8LtppruAKYMW EvRVICFvW9mBmks6tKTCOSM25oqoVQHqor4JJL084gH4POm0wBRT4zknD FFuT0lJGttVKu4Md3WDbvs8OppX/77gz5PU5ANBh558yAfcuzXnyzA6ip mWqMatvOdxBKKyLWVMyZf/b2Nzg3JHlSexNSCWH/v1ClaqKKhT+bmRt9V Q35OI30KLBhNSecpZFmTGa9q4v6BYx2u1/WC94djAtLnBwXeeDDXSCHJ/ 5oeWHMI+Lo9MI3sjVt65xw+tmngOGND6CjUa267hOiuexPqe7z1jthGAi A==; X-IronPort-AV: E=McAfee;i="6500,9779,10623"; a="331955179" X-IronPort-AV: E=Sophos;i="5.97,304,1669104000"; d="scan'208";a="331955179" 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 01:56:10 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6500,9779,10623"; a="999391208" X-IronPort-AV: E=Sophos;i="5.97,304,1669104000"; d="scan'208";a="999391208" Received: from allen-box.sh.intel.com ([10.239.159.48]) by fmsmga005.fm.intel.com with ESMTP; 17 Feb 2023 01:56:08 -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 1/6] ARM/dma-mapping: Remove iommu_detach_device() Date: Fri, 17 Feb 2023 17:47:31 +0800 Message-Id: <20230217094736.159005-2-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" iommu_detach_device() attaches the default domain to the device, or if default domain is not supported by the IOMMU driver, it calls its set_platform_dma_ops callback. If the default domain is supported or the IOMMU driver is not iommu-dma aware, iommu_detach_device() is actually a noop. The 64-bit ARM drivers always support default domain and iommu-dma is even not enabled for 32-bit ARM. This turns out that iommu_detach_device() is always a noop in arm_iommu_detach_device(). Remove it to avoid dead code. The bonus is that it also removes a obstacle of arm_iommu_detach_device() re-entering the iommu core during release_device. With this removed, the iommu core code could be simplified a lot. Signed-off-by: Lu Baolu --- arch/arm/mm/dma-mapping.c | 1 - 1 file changed, 1 deletion(-) diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c index 8bc01071474a..dcbc2f4586d4 100644 --- a/arch/arm/mm/dma-mapping.c +++ b/arch/arm/mm/dma-mapping.c @@ -1699,7 +1699,6 @@ void arm_iommu_detach_device(struct device *dev) return; } =20 - iommu_detach_device(mapping->domain, dev); kref_put(&mapping->kref, release_iommu_mapping); to_dma_iommu_mapping(dev) =3D NULL; set_dma_ops(dev, NULL); --=20 2.34.1