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 62429C05027 for ; Thu, 26 Jan 2023 23:19:15 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232851AbjAZXTO (ORCPT ); Thu, 26 Jan 2023 18:19:14 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:39712 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232506AbjAZXTI (ORCPT ); Thu, 26 Jan 2023 18:19:08 -0500 Received: from mga06.intel.com (mga06b.intel.com [134.134.136.31]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A21826A5F for ; Thu, 26 Jan 2023 15:19:07 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1674775147; x=1706311147; h=date:from:to:cc:subject:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=DxlPrkYaIFKagw6UlcDQbNMx71f4Jcar7GKHOEvVQIw=; b=OaroDJLk4oOsWsaI7QPoboa2HmhVP4tQLx9RwFzj3fY4vw8zEvadNfaW yK4aSKVy96StvX5mWZgBwpJBe/UVbZqVbOIFgaKAq2rGmlh510UMhqeOw 0HQWi0IahY5/2zKfdYT1N3QQOJ9XFVfUPBbOKK8I3k1A8vAxNAd7xeD4I 2BJi0BkKyH/7saIEXtdQx14cor6o+4PKxyMGbveaMamKrZFSMEI4z4a1Z LWW9tmkF5aNKfgVBYyfYEppnfvKJWpV6Gb98C/bVnaY/8++SXH6KMh6Uz nvXxf5V9RXdk67dGwIk7w8QCb16cuXekv+GIdLy+4oMOT0ePEH4t5vbaU w==; X-IronPort-AV: E=McAfee;i="6500,9779,10602"; a="389357770" X-IronPort-AV: E=Sophos;i="5.97,249,1669104000"; d="scan'208";a="389357770" Received: from orsmga004.jf.intel.com ([10.7.209.38]) by orsmga104.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 26 Jan 2023 15:19:07 -0800 X-IronPort-AV: E=McAfee;i="6500,9779,10602"; a="787022867" X-IronPort-AV: E=Sophos;i="5.97,249,1669104000"; d="scan'208";a="787022867" Received: from jacob-builder.jf.intel.com (HELO jacob-builder) ([10.24.100.114]) by orsmga004-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 26 Jan 2023 15:19:06 -0800 Date: Thu, 26 Jan 2023 15:22:37 -0800 From: Jacob Pan To: Robin Murphy Cc: joro@8bytes.org, will@kernel.org, iommu@lists.linux.dev, linux-kernel@vger.kernel.org, hch@lst.de, jgg@nvidia.com, baolu.lu@linux.intel.com, jacob.jun.pan@linux.intel.com Subject: Re: [PATCH v2 5/8] iommu: Switch __iommu_domain_alloc() to device ops Message-ID: <20230126152237.2f8b681f@jacob-builder> In-Reply-To: <23b51c84247cb36e96c242d3aef8ef555b6d05cd.1674753627.git.robin.murphy@arm.com> References: <23b51c84247cb36e96c242d3aef8ef555b6d05cd.1674753627.git.robin.murphy@arm.com> Organization: OTC X-Mailer: Claws Mail 3.17.5 (GTK+ 2.24.32; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Robin, On Thu, 26 Jan 2023 18:26:20 +0000, Robin Murphy wrote: > > +static int __iommu_domain_alloc_dev(struct device *dev, void *data) > +{ > + struct device **alloc_dev = data; > + > + if (!dev_iommu_ops_valid(dev)) > + return 0; > + > + WARN_ONCE(*alloc_dev && dev_iommu_ops(dev) != > dev_iommu_ops(*alloc_dev), > + "Multiple IOMMU drivers present, which the public IOMMU > API can't fully support yet. You may still need to disable one or more to > get the expected result here, sorry!\n"); + > + *alloc_dev = dev; > + return 0; > +} > + > struct iommu_domain *iommu_domain_alloc(struct bus_type *bus) > { > - return __iommu_domain_alloc(bus, IOMMU_DOMAIN_UNMANAGED); > + struct device *dev = NULL; > + > + /* We always check the whole bus, so the return value isn't > useful */ > + bus_for_each_dev(bus, NULL, &dev, __iommu_domain_alloc_dev); > + if (!dev) > + return NULL; Since __iommu_domain_alloc_dev() will always return 0, bus_for_each_dev() will never breakout until the whole dev list is iterated over. If so, would dev only record the last one? i.e. prior results get overwritten. Maybe a misunderstood the logic. > + return __iommu_domain_alloc(dev, IOMMU_DOMAIN_UNMANAGED); > } > EXPORT_SYMBOL_GPL(iommu_domain_alloc); Thanks, Jacob