From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from EUR01-DB5-obe.outbound.protection.outlook.com (mail-eopbgr150051.outbound.protection.outlook.com [40.107.15.51]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ml01.01.org (Postfix) with ESMTPS id 0E6132194EB7A for ; Thu, 13 Jun 2019 11:46:38 -0700 (PDT) From: Jason Gunthorpe Subject: Re: [PATCH 02/22] mm: remove the struct hmm_device infrastructure Date: Thu, 13 Jun 2019 18:46:36 +0000 Message-ID: <20190613184631.GO22062@mellanox.com> References: <20190613094326.24093-1-hch@lst.de> <20190613094326.24093-3-hch@lst.de> In-Reply-To: <20190613094326.24093-3-hch@lst.de> Content-Language: en-US Content-ID: <547A0314023A5340818D48E18E9DA700@eurprd05.prod.outlook.com> MIME-Version: 1.0 List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: linux-nvdimm-bounces@lists.01.org Sender: "Linux-nvdimm" To: Christoph Hellwig Cc: "linux-nvdimm@lists.01.org" , "nouveau@lists.freedesktop.org" , "linux-kernel@vger.kernel.org" , "dri-devel@lists.freedesktop.org" , "linux-mm@kvack.org" , =?iso-8859-1?Q?J=E9r=F4me_Glisse?= , Ben Skeggs , "linux-pci@vger.kernel.org" List-ID: On Thu, Jun 13, 2019 at 11:43:05AM +0200, Christoph Hellwig wrote: > This code is a trivial wrapper around device model helpers, which > should have been integrated into the driver device model usage from > the start. Assuming it actually had users, which it never had since > the code was added more than 1 1/2 years ago. > > Signed-off-by: Christoph Hellwig > --- > include/linux/hmm.h | 20 ------------ > mm/hmm.c | 80 --------------------------------------------- > 2 files changed, 100 deletions(-) I haven't looked in detail at this device memory stuff.. But I did check a bit through the mailing list archives for some clue what this was supposed to be for (wow, this is from 2016!) The commit that added this says: This introduce a dummy HMM device class so device driver can use it to create hmm_device for the sole purpose of registering device memory. Which I just can't understand at all. If we need a 'struct device' for some 'device memory' purpose then it probably ought to be the 'struct pci_device' holding the BAR, not a fake device. I also can't comprehend why a supposed fake device would need a chardev, with a stanadrd 'hmm_deviceX' name, without also defining a core kernel ABI for that char dev.. If this comes back it needs a proper explanation and review, with a user. Reviewed-by: Jason Gunthorpe Jason _______________________________________________ Linux-nvdimm mailing list Linux-nvdimm@lists.01.org https://lists.01.org/mailman/listinfo/linux-nvdimm