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 0F186CCA47F for ; Tue, 5 Jul 2022 17:22:07 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232704AbiGERWF (ORCPT ); Tue, 5 Jul 2022 13:22:05 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43966 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229779AbiGERWE (ORCPT ); Tue, 5 Jul 2022 13:22:04 -0400 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 89D6512AD2; Tue, 5 Jul 2022 10:22:03 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id 41EA6B8182F; Tue, 5 Jul 2022 17:22:02 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 5A3CBC341C7; Tue, 5 Jul 2022 17:22:00 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1657041720; bh=2k+PI3826bV0JfafuKOYWZwzEmZ/6OWZBqa+5FOwKKU=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=eW0LSj5OCSMxFTwab7kOj8yB3ANUifdcIyjdDqyqljZ/iy8fnpSDRDB1hx7AhAPR2 x0qZP6dDTeDA8ifC5C2gTw8/5BH/5dH8LBx4m8NjuS/wZ8PPrtzbO2zUPRMEQWtCnE Ysh75bL4zKRSbMgqYVPy39v9+8C6x63MzOq+Bpnc= Date: Tue, 5 Jul 2022 19:21:58 +0200 From: Greg Kroah-Hartman To: Christoph Hellwig Cc: Logan Gunthorpe , 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: References: <20220629064854.GD17576@lst.de> <99242789-66a6-bbd2-b56a-e47891f4522e@deltatee.com> <20220629175906.GU23621@ziepe.ca> <20220705075108.GB17451@lst.de> <20220705135102.GE23621@ziepe.ca> <20220705161240.GB13721@lst.de> <20220705164315.GB14484@lst.de> <20220705165039.GB14566@lst.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220705165039.GB14566@lst.de> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Jul 05, 2022 at 06:50:39PM +0200, Christoph Hellwig wrote: > [note for the newcomers, this is about allowing mmap()ing the PCIe > P2P memory from the generic PCI P2P code through sysfs, and more > importantly how to revoke it on device removal] We allow mmap on PCIe config space today, right? Why is this different from what pci_create_legacy_files() does today? > On Tue, Jul 05, 2022 at 10:44:49AM -0600, Logan Gunthorpe wrote: > > We might be able to. I'm not sure. I'll have to figure out how to find > > that inode from the p2pdma code. I haven't found an obvious interface to > > do that. > > I think the right way to approach this would be a new sysfs API > that internally calls unmap_mapping_range internally instead of > exposing the inode. I suspect that might actually be the right thing > to do for iomem_inode as well. Why do we need something new and how is this any different from the PCI binary files I mention above? We have supported PCI hotplug for a very long time, do the current PCI binary sysfs files not work properly with mmap and removing a device? thanks, greg k-h