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Fri, 15 Oct 2021 11:29:38 +0000 From: "Liu, Yi L" To: Jason Gunthorpe CC: "alex.williamson@redhat.com" , "hch@lst.de" , "jasowang@redhat.com" , "joro@8bytes.org" , "jean-philippe@linaro.org" , "Tian, Kevin" , "parav@mellanox.com" , "lkml@metux.net" , "pbonzini@redhat.com" , "lushenming@huawei.com" , "eric.auger@redhat.com" , "corbet@lwn.net" , "Raj, Ashok" , "yi.l.liu@linux.intel.com" , "Tian, Jun J" , "Wu, Hao" , "Jiang, Dave" , "jacob.jun.pan@linux.intel.com" , "kwankhede@nvidia.com" , "robin.murphy@arm.com" , "kvm@vger.kernel.org" , "iommu@lists.linux-foundation.org" , "dwmw2@infradead.org" , "linux-kernel@vger.kernel.org" , "baolu.lu@linux.intel.com" , "david@gibson.dropbear.id.au" , "nicolinc@nvidia.com" Subject: RE: [RFC 01/20] iommu/iommufd: Add /dev/iommu core Thread-Topic: [RFC 01/20] iommu/iommufd: Add /dev/iommu core Thread-Index: AQHXrSFn+yRWuHvsGk21Z769W7oSJKuupBEAgCVKaUCAACPrgIAAAxPQ Date: Fri, 15 Oct 2021 11:29:38 +0000 Message-ID: References: <20210919063848.1476776-1-yi.l.liu@intel.com> <20210919063848.1476776-2-yi.l.liu@intel.com> <20210921154138.GM327412@nvidia.com> <20211015111807.GD2744544@nvidia.com> In-Reply-To: <20211015111807.GD2744544@nvidia.com> Accept-Language: en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: authentication-results: nvidia.com; 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charset="us-ascii" Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 X-MS-Exchange-CrossTenant-AuthAs: Internal X-MS-Exchange-CrossTenant-AuthSource: PH0PR11MB5658.namprd11.prod.outlook.com X-MS-Exchange-CrossTenant-Network-Message-Id: d91e6b4c-0e43-4b15-2536-08d98fcf12b0 X-MS-Exchange-CrossTenant-originalarrivaltime: 15 Oct 2021 11:29:38.1682 (UTC) X-MS-Exchange-CrossTenant-fromentityheader: Hosted X-MS-Exchange-CrossTenant-id: 46c98d88-e344-4ed4-8496-4ed7712e255d X-MS-Exchange-CrossTenant-mailboxtype: HOSTED X-MS-Exchange-CrossTenant-userprincipalname: 3wwuHHIx6PMaX53WmuspXMdJdhQypcsg2MbRerc0ACuYm+QpIzItT5asdZgZR394W8KqPscKjqj9ajuQD/uGqQ== X-MS-Exchange-Transport-CrossTenantHeadersStamped: PH0PR11MB5642 X-OriginatorOrg: intel.com Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org > From: Jason Gunthorpe > Sent: Friday, October 15, 2021 7:18 PM >=20 > On Fri, Oct 15, 2021 at 09:18:06AM +0000, Liu, Yi L wrote: >=20 > > > Acquire from the xarray is > > > rcu_lock() > > > ioas =3D xa_load() > > > if (ioas) > > > if (down_read_trylock(&ioas->destroying_lock)) > > > > all good suggestions, will refine accordingly. Here destroying_lock is = a > > rw_semaphore. right? Since down_read_trylock() accepts a rwsem. >=20 > Yes, you probably need a sleeping lock got it. thanks, Regards, Yi Liu 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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 7A432C433EF for ; Fri, 15 Oct 2021 11:29:47 +0000 (UTC) Received: from smtp3.osuosl.org (smtp3.osuosl.org [140.211.166.136]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 2B23B6101E for ; Fri, 15 Oct 2021 11:29:47 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 2B23B6101E Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=intel.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=lists.linux-foundation.org Received: from localhost (localhost [127.0.0.1]) by smtp3.osuosl.org (Postfix) with ESMTP id E7E7C60688; 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charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: iommu-bounces@lists.linux-foundation.org Sender: "iommu" > From: Jason Gunthorpe > Sent: Friday, October 15, 2021 7:18 PM > > On Fri, Oct 15, 2021 at 09:18:06AM +0000, Liu, Yi L wrote: > > > > Acquire from the xarray is > > > rcu_lock() > > > ioas = xa_load() > > > if (ioas) > > > if (down_read_trylock(&ioas->destroying_lock)) > > > > all good suggestions, will refine accordingly. Here destroying_lock is a > > rw_semaphore. right? Since down_read_trylock() accepts a rwsem. > > Yes, you probably need a sleeping lock got it. thanks, Regards, Yi Liu _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu