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 X-Spam-Level: X-Spam-Status: No, score=-2.4 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,UNPARSEABLE_RELAY,USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 70F3BC433E1 for ; Fri, 29 May 2020 11:54:02 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4A1A8207F5 for ; Fri, 29 May 2020 11:54:02 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=oracle.com header.i=@oracle.com header.b="S3Sr0pZe" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726799AbgE2LyB (ORCPT ); Fri, 29 May 2020 07:54:01 -0400 Received: from aserp2120.oracle.com ([141.146.126.78]:49964 "EHLO aserp2120.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725775AbgE2Lx6 (ORCPT ); Fri, 29 May 2020 07:53:58 -0400 Received: from pps.filterd (aserp2120.oracle.com [127.0.0.1]) by aserp2120.oracle.com (8.16.0.42/8.16.0.42) with SMTP id 04TBqG6r143006; Fri, 29 May 2020 11:53:49 GMT DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=oracle.com; h=date : from : to : cc : subject : message-id : references : mime-version : content-type : in-reply-to; s=corp-2020-01-29; bh=Btj8TnsnvVtswy+efh0SNsqef1MHWBON7iyK08stdgk=; b=S3Sr0pZeV8W2oX7blFHa/S4XEL7FNBaGuMflJ3Z47YrETokhco7nq4VJG4A+TGa56LTv NZ76rVb12QqJv7Tya7n9abEsUFqVHa2Vn0I1GA9MfCPEp2sWYjahHMOZriOMiJPvRbbV EUlMCoWkTG09clNRuwqMjmu2ZcxNA0FO7QI3hLNpT+32VDAnVBgFxXbI2pnbhmyrnmBv ro1O/icBMJVnOOk9GV3X640Ix/JRsr1Xo6L5LhRyz/sEesmn3lgh6slftDS4Vk3A7Bpz ZMEW8b3Vo1k1a4I1xfm0HI91k0NN+YVOckAAGatIGiVlva99wHqllWvtSRwwurespk5T bg== Received: from userp3020.oracle.com (userp3020.oracle.com [156.151.31.79]) by aserp2120.oracle.com with ESMTP id 318xe1sxhy-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=FAIL); Fri, 29 May 2020 11:53:48 +0000 Received: from pps.filterd (userp3020.oracle.com [127.0.0.1]) by userp3020.oracle.com (8.16.0.42/8.16.0.42) with SMTP id 04TBricA129324; Fri, 29 May 2020 11:53:48 GMT Received: from aserv0121.oracle.com (aserv0121.oracle.com [141.146.126.235]) by userp3020.oracle.com with ESMTP id 31a9ku4jqc-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Fri, 29 May 2020 11:53:48 +0000 Received: from abhmp0005.oracle.com (abhmp0005.oracle.com [141.146.116.11]) by aserv0121.oracle.com (8.14.4/8.13.8) with ESMTP id 04TBrkXw030487; Fri, 29 May 2020 11:53:47 GMT Received: from kadam (/41.57.98.10) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Fri, 29 May 2020 04:53:46 -0700 Date: Fri, 29 May 2020 14:53:30 +0300 From: Dan Carpenter To: Souptick Joarder Cc: devel@driverdev.osuosl.org, gregkh@linuxfoundation.org, linux-kernel@vger.kernel.org, rspringer@google.com, John Hubbard , toddpoynor@google.com Subject: Re: [PATCH] staging: gasket: Convert get_user_pages*() --> pin_user_pages*() Message-ID: <20200529115330.GO30374@kadam> References: <1590613362-27495-1-git-send-email-jrdr.linux@gmail.com> <20200528110408.GJ30374@kadam> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200528110408.GJ30374@kadam> User-Agent: Mutt/1.9.4 (2018-02-28) X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9635 signatures=668686 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 suspectscore=0 mlxscore=0 adultscore=0 mlxlogscore=999 malwarescore=0 spamscore=0 bulkscore=0 phishscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2004280000 definitions=main-2005290096 X-Proofpoint-Virus-Version: vendor=nai engine=6000 definitions=9635 signatures=668686 X-Proofpoint-Spam-Details: rule=notspam policy=default score=0 spamscore=0 mlxlogscore=999 adultscore=0 cotscore=-2147483648 mlxscore=0 bulkscore=0 priorityscore=1501 phishscore=0 lowpriorityscore=0 malwarescore=0 clxscore=1015 impostorscore=0 suspectscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2004280000 definitions=main-2005290096 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Anyway, can you resend with the commit message re-written. To me the information that's most useful is from the lwn article: "In short, if pages are being pinned for access to the data contained within those pages, pin_user_pages() should be used. For cases where the intent is to manipulate the page structures corresponding to the pages rather than the data within them, get_user_pages() is the correct interface." What are the runtime implications of this patch? I'm still not clear on that honestly. When I'm reviewing patches, I also want to know how a bug was introduced. In this case the original author did everything correctly but we've just added some new features (cleanups. whatever). I did skim the LWN article back in December but I don't remember the details so I really want all this stuff re-stated in each commit message. regards, dan carpenter