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 71EB2CCA47F for ; Wed, 6 Jul 2022 06:51:35 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230032AbiGFGve (ORCPT ); Wed, 6 Jul 2022 02:51:34 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:46514 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229459AbiGFGvd (ORCPT ); Wed, 6 Jul 2022 02:51:33 -0400 Received: from verein.lst.de (verein.lst.de [213.95.11.211]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D4D5614D0B; Tue, 5 Jul 2022 23:51:32 -0700 (PDT) Received: by verein.lst.de (Postfix, from userid 2407) id 79E0F67373; Wed, 6 Jul 2022 08:51:27 +0200 (CEST) Date: Wed, 6 Jul 2022 08:51:27 +0200 From: Christoph Hellwig To: Logan Gunthorpe Cc: Greg Kroah-Hartman , Christoph Hellwig , Jason Gunthorpe , linux-kernel@vger.kernel.org, linux-nvme@lists.infradead.org, linux-block@vger.kernel.org, linux-pci@vger.kernel.org, linux-mm@kvack.org, iommu@lists.linux-foundation.org, Stephen Bates , Dan Williams , Christian =?iso-8859-1?Q?K=F6nig?= , John Hubbard , Don Dutile , Matthew Wilcox , Daniel Vetter , Minturn Dave B , Jason Ekstrand , Dave Hansen , Xiong Jianxin , Bjorn Helgaas , Ira Weiny , Robin Murphy , Martin Oliveira , Chaitanya Kulkarni , Ralph Campbell , Bjorn Helgaas Subject: Re: [PATCH v7 20/21] PCI/P2PDMA: Introduce pci_mmap_p2pmem() Message-ID: <20220706065127.GA27132@lst.de> References: <20220705135102.GE23621@ziepe.ca> <20220705161240.GB13721@lst.de> <20220705164315.GB14484@lst.de> <20220705165039.GB14566@lst.de> <1bd43ef7-0403-bd25-087c-d54d5af677e4@deltatee.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.17 (2007-11-01) Precedence: bulk List-ID: X-Mailing-List: linux-block@vger.kernel.org On Tue, Jul 05, 2022 at 12:16:45PM -0600, Logan Gunthorpe wrote: > The current version does it through a char device, but that requires > creating a simple_fs and anon_inode for teardown on driver removal, plus > a bunch of hooks through the driver that exposes it (NVMe, in this case) > to set this all up. > > Christoph is suggesting a sysfs interface which could potentially avoid > the anon_inode and all of the extra hooks. It has some significant > benefits and maybe some small downsides, but I wouldn't describe it as > horrid. Yeah, I don't think is is horrible, it fits in with the resource files for the BARs, and solves a lot of problems. Greg, can you explain what would be so bad about it? 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 smtp4.osuosl.org (smtp4.osuosl.org [140.211.166.137]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 66323C43334 for ; Wed, 6 Jul 2022 06:51:39 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by smtp4.osuosl.org (Postfix) with ESMTP id D91AA41761; Wed, 6 Jul 2022 06:51:38 +0000 (UTC) DKIM-Filter: OpenDKIM Filter v2.11.0 smtp4.osuosl.org D91AA41761 X-Virus-Scanned: amavisd-new at osuosl.org Received: from smtp4.osuosl.org ([127.0.0.1]) by localhost (smtp4.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id skXHQ2iC3XpL; Wed, 6 Jul 2022 06:51:38 +0000 (UTC) Received: from lists.linuxfoundation.org (lf-lists.osuosl.org [IPv6:2605:bc80:3010:104::8cd3:938]) by smtp4.osuosl.org (Postfix) with ESMTPS id 80B4E414A2; Wed, 6 Jul 2022 06:51:37 +0000 (UTC) DKIM-Filter: OpenDKIM Filter v2.11.0 smtp4.osuosl.org 80B4E414A2 Received: from lf-lists.osuosl.org (localhost [127.0.0.1]) by lists.linuxfoundation.org (Postfix) with ESMTP id 5EF16C0077; Wed, 6 Jul 2022 06:51:37 +0000 (UTC) Received: from smtp4.osuosl.org (smtp4.osuosl.org [IPv6:2605:bc80:3010::137]) by lists.linuxfoundation.org (Postfix) with ESMTP id B093AC0070 for ; Wed, 6 Jul 2022 06:51:35 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by smtp4.osuosl.org (Postfix) with ESMTP id 75C8141730 for ; Wed, 6 Jul 2022 06:51:35 +0000 (UTC) DKIM-Filter: OpenDKIM Filter v2.11.0 smtp4.osuosl.org 75C8141730 X-Virus-Scanned: amavisd-new at osuosl.org Received: from smtp4.osuosl.org ([127.0.0.1]) by localhost (smtp4.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id 7bf7Ogti5b1M for ; Wed, 6 Jul 2022 06:51:34 +0000 (UTC) X-Greylist: from auto-whitelisted by SQLgrey-1.8.0 DKIM-Filter: OpenDKIM Filter v2.11.0 smtp4.osuosl.org 0B687414A2 Received: from verein.lst.de (verein.lst.de [213.95.11.211]) by smtp4.osuosl.org (Postfix) with ESMTPS id 0B687414A2 for ; Wed, 6 Jul 2022 06:51:33 +0000 (UTC) Received: by verein.lst.de (Postfix, from userid 2407) id 79E0F67373; Wed, 6 Jul 2022 08:51:27 +0200 (CEST) Date: Wed, 6 Jul 2022 08:51:27 +0200 From: Christoph Hellwig To: Logan Gunthorpe Subject: Re: [PATCH v7 20/21] PCI/P2PDMA: Introduce pci_mmap_p2pmem() Message-ID: <20220706065127.GA27132@lst.de> References: <20220705135102.GE23621@ziepe.ca> <20220705161240.GB13721@lst.de> <20220705164315.GB14484@lst.de> <20220705165039.GB14566@lst.de> <1bd43ef7-0403-bd25-087c-d54d5af677e4@deltatee.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.17 (2007-11-01) Cc: Daniel Vetter , Dave Hansen , linux-nvme@lists.infradead.org, Stephen Bates , linux-mm@kvack.org, Jason Ekstrand , Ira Weiny , Christoph Hellwig , Minturn Dave B , Martin Oliveira , Matthew Wilcox , Jason Gunthorpe , Chaitanya Kulkarni , Bjorn Helgaas , linux-pci@vger.kernel.org, Ralph Campbell , John Hubbard , linux-block@vger.kernel.org, Bjorn Helgaas , Dan Williams , Xiong Jianxin , Greg Kroah-Hartman , linux-kernel@vger.kernel.org, iommu@lists.linux-foundation.org, Robin Murphy , Christian =?iso-8859-1?Q?K=F6nig?= X-BeenThere: iommu@lists.linux-foundation.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: Development issues for Linux IOMMU support List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: iommu-bounces@lists.linux-foundation.org Sender: "iommu" On Tue, Jul 05, 2022 at 12:16:45PM -0600, Logan Gunthorpe wrote: > The current version does it through a char device, but that requires > creating a simple_fs and anon_inode for teardown on driver removal, plus > a bunch of hooks through the driver that exposes it (NVMe, in this case) > to set this all up. > > Christoph is suggesting a sysfs interface which could potentially avoid > the anon_inode and all of the extra hooks. It has some significant > benefits and maybe some small downsides, but I wouldn't describe it as > horrid. Yeah, I don't think is is horrible, it fits in with the resource files for the BARs, and solves a lot of problems. Greg, can you explain what would be so bad about it? _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu