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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id A37EEC27C52 for ; Thu, 6 Jun 2024 20:54:14 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 3B6D96B008A; Thu, 6 Jun 2024 16:54:14 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 366B86B00A6; Thu, 6 Jun 2024 16:54:14 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 255666B00AA; Thu, 6 Jun 2024 16:54:14 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0010.hostedemail.com [216.40.44.10]) by kanga.kvack.org (Postfix) with ESMTP id 06A066B008A for ; Thu, 6 Jun 2024 16:54:14 -0400 (EDT) Received: from smtpin30.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay05.hostedemail.com (Postfix) with ESMTP id 5EC08409C9 for ; Thu, 6 Jun 2024 20:54:13 +0000 (UTC) X-FDA: 82201666386.30.B879A27 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by imf04.hostedemail.com (Postfix) with ESMTP id 8461A4000F for ; Thu, 6 Jun 2024 20:54:11 +0000 (UTC) Authentication-Results: imf04.hostedemail.com; dkim=pass header.d=linuxfoundation.org header.s=korg header.b=A6kyP1N4; spf=pass (imf04.hostedemail.com: domain of gregkh@linuxfoundation.org designates 139.178.84.217 as permitted sender) smtp.mailfrom=gregkh@linuxfoundation.org; dmarc=pass (policy=none) header.from=linuxfoundation.org ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1717707251; a=rsa-sha256; cv=none; b=NLUqN9tzkS3NObtVlsqGzUgemeHraMHfZp8VuHw6p/8QScMbWsaJisizgYtw7P4IcJwLlU N7VgMxTpNINdKdxTKJMa64wvyGeKzdW1ZlfkDoIq34/T9pJq4erSQPHY3Mtj35jLTTXKyk N+4ev4Odvjwr3DhHnH2juOpNpkE+7VU= ARC-Authentication-Results: i=1; imf04.hostedemail.com; dkim=pass header.d=linuxfoundation.org header.s=korg header.b=A6kyP1N4; spf=pass (imf04.hostedemail.com: domain of gregkh@linuxfoundation.org designates 139.178.84.217 as permitted sender) smtp.mailfrom=gregkh@linuxfoundation.org; dmarc=pass (policy=none) header.from=linuxfoundation.org ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1717707251; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=fLVuCQX2DNezLS2JHa31w+B9qkLac0MTzxigY7z1vXo=; b=A56CAqEMQyHIP1A+1m9hR3FWJ6It8BSTACDgn3OP0qynrMhS0iAP7H48X6ifrXbC89CDdL SyfvgLqudbmuHdc97vN/qvkvSISjO4KuYTzTfy0ue8fHLo7sK1g3CXCJY4gJD6KI8YRXB0 0e/Wd+8OE3VV818YsFXmqmxNR0JZWJQ= Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by dfw.source.kernel.org (Postfix) with ESMTP id DD38B61E97; Thu, 6 Jun 2024 20:54:08 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 59061C2BD10; Thu, 6 Jun 2024 20:54:08 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1717707248; bh=UqeI96+MM5X3pqwCptXH2eQJ3yuc1OFxEnYiSX/y3zc=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=A6kyP1N4dXj3GzUHpLannf6y6D/DZdpilO3+TVH+Fi8roM8Aj39obTruHOHQheVuo UJwXzYsvbA9zFqU5zAV9iT651Za7HI5PQpS0joWloWlz6gfYZXd5/Xg1juzOG9Jn4T 4c7WbLPv3KG8D/bcooMr+zVEgBpvvB94WvCxd0eE= Date: Thu, 6 Jun 2024 22:54:06 +0200 From: Greg Kroah-Hartman To: Martin Oliveira Cc: linux-rdma@vger.kernel.org, linux-kernel@vger.kernel.org, linux-pci@vger.kernel.org, linux-mm@kvack.org, Jason Gunthorpe , Leon Romanovsky , Bjorn Helgaas , Logan Gunthorpe , Tejun Heo , "Rafael J. Wysocki" , Andrew Morton , Mike Marciniszyn , Michael Guralnik , Dan Williams , Ard Biesheuvel , Valentine Sinitsyn , Lukas Wunner Subject: Re: [PATCH 1/6] kernfs: create vm_operations_struct without page_mkwrite() Message-ID: <2024060658-ember-unblessed-4c74@gregkh> References: <20240605192934.742369-1-martin.oliveira@eideticom.com> <20240605192934.742369-2-martin.oliveira@eideticom.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20240605192934.742369-2-martin.oliveira@eideticom.com> X-Rspamd-Queue-Id: 8461A4000F X-Rspam-User: X-Rspamd-Server: rspam12 X-Stat-Signature: zbr3ixz4efsr5wjcdqggkddif5tu9ko1 X-HE-Tag: 1717707251-152034 X-HE-Meta: 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 9Rj4vdk/ RhmHyERdlBp9ShebAKOg4VpZ4OKUDK8qiXqkhl7J+9Iq9KWwGrZcV1ZnwDTS3CAD+V1gbU20yPyMgDNv7mJ2Y0rAAwFnlomh+WoIvketpXYBc5G8IL396JVyQo5RtBRMoyZYpOprvkKklI06tlDY2omV4ZZl7l+f+u4WzSpi0PCMZE7KsA2X2CORNXsSFOJiT6nq4hbeGTNIYhDuJXcjLw8YkJHJGMa6CRe8+yf9xQxGWsYBgfU9oN6U3Gz2s+QfQaG7HK7KE/0FFPCo= X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Wed, Jun 05, 2024 at 01:29:29PM -0600, Martin Oliveira wrote: > The standard kernfs vm_ops installs a page_mkwrite() operator which > modifies the file update time on write. > > This not always required (or makes sense), such as in the P2PDMA, which > uses the sysfs file as an allocator from userspace. That's not a good idea, please don't do that. sysfs binary files are "pass through", why would you want to use this as an allocator? > Furthermore, having the page_mkwrite() operator causes > writable_file_mapping_allowed() to fail due to > vma_needs_dirty_tracking() on the gup flow, which is a pre-requisite for > enabling P2PDMA over RDMA. > > Fix this by adding a new boolean on kernfs_ops to differentiate between > the different behaviours. This isn't going to work well. What exactly are you wanting to do in sysfs that you feel this is required? thanks, greg k-h