Date:   Wed, 15 Feb 2023 08:49:17 -0400
From:   Jason Gunthorpe <jgg@nvidia.com>
To:     Jacob Pan <jacob.jun.pan@linux.intel.com>
Cc:     Jean-Philippe Brucker <jean-philippe@linaro.org>,
        LKML <linux-kernel@vger.kernel.org>, iommu@lists.linux.dev,
        Lu Baolu <baolu.lu@linux.intel.com>,
        Joerg Roedel <joro@8bytes.org>,
        Jean-Philippe Brucker <jean-philippe@linaro.com>,
        Robin Murphy <robin.murphy@arm.com>,
        Will Deacon <will@kernel.org>,
        David Woodhouse <dwmw2@infradead.org>,
        Raj Ashok <ashok.raj@intel.com>,
        "Tian, Kevin" <kevin.tian@intel.com>, Yi Liu <yi.l.liu@intel.com>
Subject: Re: [PATCH v2 3/3] iommu: Remove ioasid infrastructure
Message-ID: <Y+zUzQqRE4LfarZJ@nvidia.com>
References: <20230214064414.1038058-1-jacob.jun.pan@linux.intel.com>
 <20230214064414.1038058-4-jacob.jun.pan@linux.intel.com>
 <Y+tVMRzRQbcc7Guz@myrica>
 <Y+uHSry/tpgGNr/b@nvidia.com>
 <20230214093107.323d7e76@jacob-builder>
 <Y+vLiWS3+Rp+If6U@nvidia.com>
 <20230214133352.1f69b624@jacob-builder>
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <20230214133352.1f69b624@jacob-builder>
MIME-Version: 1.0
X-MS-Exchange-AntiSpam-MessageData-ChunkCount: 1
X-MS-Exchange-AntiSpam-MessageData-0: =?us-ascii?Q?ZCWDDR5SYOdCJC0v6LIQIetJQyzQHhdORz49FaJXwqsA0akU/IpGFsxAsKhf?=
 =?us-ascii?Q?8Die0dFs5yd4K5Cp2+ZOAmY5I5ITX946P/wUmmH/sa+xCKw47kKaWbLkJnmF?=
 =?us-ascii?Q?Zmt/e3ACKBV/PQ7vSFsTECpbqi0AYuBGDdK5uu1IN1+9UDnhahflMF8aedAQ?=
 =?us-ascii?Q?PlRgtRfBP+Vsff3IwDP43CqQRVsHF1r3/7qqVrhzVGdksNjevkhEFxJjdPvt?=
 =?us-ascii?Q?6kwOpAJINQbPWI0HHM4fnmfxmWTS9SjoeuiWyyQURJmJq/0qh6TtdWYxvm7/?=
 =?us-ascii?Q?poZJQUvlfZXLmoWBSzen4rXz0Kag0+Ax5KioxVXwQyYsqjss/KHg28lYvBr0?=
 =?us-ascii?Q?sxAYtagYn3oj58lVB7BUpqbc2B+LiBNKBUQ17AhpHh0rRoS+ihyVuqIw43Dm?=
 =?us-ascii?Q?txiCtqIHL7W7ea/e5LdVIK6TnYAivc5Rt8nBXxzBOfXu63j2hIUB8Kqej1SF?=
 =?us-ascii?Q?txjeHL79LwrZ/gxr3u+nKxjwtEMaN7JeF/Fo7BKj2IrLYsvAlDbIWeEfVicF?=
 =?us-ascii?Q?7g2XhVoHmBx49foIZPRAWC6ZXVXlf9i969CtfSJfAUD2Hd+K09pkoiN0FjzV?=
 =?us-ascii?Q?48O8xdDqm2gR+YqTljN4O5yd7dassjpilVMRS3EGGqBQddJsYQRFuRatyzHF?=
 =?us-ascii?Q?e2Wl3esU+26o2hv066bEwij9wDB5le6y5Z1Bq2CTXm9ktiJPQb5NDQOqHc+s?=
 =?us-ascii?Q?jlMXQ8nWAzxYlAugfabOlunnNTmkH7jjLHtQEb48yRtPqDpDFAvlOfce2mVQ?=
 =?us-ascii?Q?MezVXq3J2kg0BCGg9u/ERhjG9J/sLSwX1eTMnzS61HhWs5IBWYcxVV7/ZmUu?=
 =?us-ascii?Q?NbPWT9GD2ZEpTXuizuhQAQ6gblvPckMiyow2ZwsAPna+RmvUnHxNZVqxJki7?=
 =?us-ascii?Q?bFdYA/tdPgrPfBOn5haFoOvy7n+++oxQldYuHwDF62Hbnrt60XfxWq5sX6mo?=
 =?us-ascii?Q?oAQpEchBsrHdAfHdeZHi72/0O82610o69CX6LJQtVJBU1vm1Fcp2S/6BGunJ?=
 =?us-ascii?Q?UlLrCmNoNaKS3rcfpCgGhj+8wibnLsxzHdwIIRfGSE10Mvf3Bq5zt/A+082D?=
 =?us-ascii?Q?qCwBOCoPH9QF1tNKE0ydJSACK00NIkfmV5pVlt6ZngN/zSDp4uNyYqj0zNm9?=
 =?us-ascii?Q?tejzKJcxqyqK+ukD1j72dXUBMHbMp3ZPs1VRtvJWXJGBZbCdbbGDzfq9FmOj?=
 =?us-ascii?Q?q+JyfzRnsKNyiMoHVAY3ylALC8tU+a4dP3oexKWbzIX6RrPhMLGpuiBs3cvx?=
 =?us-ascii?Q?T5wbZ2XILCfLbC9jur7p5HpWpJgT75xyemJk2mYXMF8mHyWPAEnRbr0ge/1q?=
 =?us-ascii?Q?A7iN6EfRKHoQGzFmmhiCjF2jJ9To+YHOyrKDm6PzbQJBw14K4/JmcM8oIQM0?=
 =?us-ascii?Q?MTzquYGVjEKy1wnQ0CO4Sh+FFhULetIabwXVwPO4cM51DSnYkvTPtxFmnTTq?=
 =?us-ascii?Q?EgK6SwRV2xgZs9gKugyXC9EtLqU/Gfv6934RbnmmUmLRaLF1qmmmZc4laR7n?=
 =?us-ascii?Q?cnV+ASKjtBuCLqH3fLy6BEe9pNd3z2JavKnoGuANLqd1eRvTmvzM41tDBykh?=
 =?us-ascii?Q?t2o7ARBHwozIAyrMPlTycZZe2uCVFhxm6XNy2fBP?=
X-OriginatorOrg: Nvidia.com
X-MS-Exchange-CrossTenant-Network-Message-Id: bcabf702-9329-4d29-7898-08db0f530d1a
X-MS-Exchange-CrossTenant-AuthSource: LV2PR12MB5869.namprd12.prod.outlook.com
X-MS-Exchange-CrossTenant-AuthAs: Internal
X-MS-Exchange-CrossTenant-OriginalArrivalTime: 15 Feb 2023 12:49:18.1003
 (UTC)
X-MS-Exchange-CrossTenant-FromEntityHeader: Hosted
X-MS-Exchange-CrossTenant-Id: 43083d15-7273-40c1-b7db-39efd9ccc17a
X-MS-Exchange-CrossTenant-MailboxType: HOSTED
X-MS-Exchange-CrossTenant-UserPrincipalName: 5frLFZx+42B9Yty3llmb3YZsLWW1cIjKNQ2uC1mnsA2+hTnFCV+y8Y0pjv9rzGXo
X-MS-Exchange-Transport-CrossTenantHeadersStamped: SA0PR12MB4576
Precedence: bulk
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org

On Tue, Feb 14, 2023 at 01:33:52PM -0800, Jacob Pan wrote:
> Hi Jason,
> 
> On Tue, 14 Feb 2023 13:57:29 -0400, Jason Gunthorpe <jgg@nvidia.com> wrote:
> 
> > On Tue, Feb 14, 2023 at 09:31:07AM -0800, Jacob Pan wrote:
> > > Hi Jason,
> > > 
> > > On Tue, 14 Feb 2023 09:06:18 -0400, Jason Gunthorpe <jgg@nvidia.com>
> > > wrote: 
> > > > On Tue, Feb 14, 2023 at 09:32:33AM +0000, Jean-Philippe Brucker
> > > > wrote:  
> > > > > > diff --git a/include/uapi/linux/iommu.h
> > > > > > b/include/uapi/linux/iommu.h index 65d8b0234f69..a95f07f0c98c
> > > > > > 100644 --- a/include/uapi/linux/iommu.h
> > > > > > +++ b/include/uapi/linux/iommu.h
> > > > > > @@ -157,5 +157,6 @@ struct iommu_page_response {
> > > > > >  	__u32	grpid;
> > > > > >  	__u32	code;
> > > > > >  };
> > > > > > +#define IOMMU_PASID_INVALID	(-1U)    
> > > > > 
> > > > > Why change UAPI?    
> > > > 
> > > > There is no uapi, this whole file needs to be deleted too
> > > >   
> > > ok. another clean up.
> > > 
> > > As I also replied to Jean, I ran into a circular #include problem if
> > > mm.h #include iommu.h, I guess I could also create another header, e.g.
> > > iommu_defs.h to avoid it. any other suggestions?  
> > 
> > Given this header is not used, just delete things from it to resolve
> > the problem?
> no, sorry i didn't make it clear. I meant if we do #include <linux/iommu.h>
> in sched/mm.h, then I got circular include problem.

You shouldn't do that at all, mm.h is included everywhere.

Try to make it smaller not larger.

You are better to include iommu.h in the few .c files that need these
shims than put them in mm.h

Jason