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=-10.2 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=ham 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 42590C432BE for ; Thu, 12 Aug 2021 09:22:09 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 6512A61058 for ; Thu, 12 Aug 2021 09:22:08 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 6512A61058 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=lst.de Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=kvack.org Received: by kanga.kvack.org (Postfix) id F02316B0072; Thu, 12 Aug 2021 05:22:07 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id EB15A6B0073; Thu, 12 Aug 2021 05:22:07 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id DC7C48D0009; Thu, 12 Aug 2021 05:22:07 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0208.hostedemail.com [216.40.44.208]) by kanga.kvack.org (Postfix) with ESMTP id C373F6B0072 for ; Thu, 12 Aug 2021 05:22:07 -0400 (EDT) Received: from smtpin40.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay05.hostedemail.com (Postfix) with ESMTP id 28B921839A9F3 for ; Thu, 12 Aug 2021 09:22:07 +0000 (UTC) X-FDA: 78465887094.40.5008780 Received: from verein.lst.de (verein.lst.de [213.95.11.211]) by imf01.hostedemail.com (Postfix) with ESMTP id C40975042A08 for ; Thu, 12 Aug 2021 09:22:06 +0000 (UTC) Received: by verein.lst.de (Postfix, from userid 2407) id A512367373; Thu, 12 Aug 2021 11:22:04 +0200 (CEST) Date: Thu, 12 Aug 2021 11:22:04 +0200 From: Christoph Hellwig To: John Hubbard Cc: Andrew Morton , Heiko Carstens , Vasily Gorbik , Christian Borntraeger , LKML , linux-mm@kvack.org, linux-s390@vger.kernel.org, linux-fsdevel@vger.kernel.org, Christoph Hellwig , Matthew Wilcox Subject: Re: [PATCH v2 3/3] mm/gup: Remove try_get_page(), call try_get_compound_head() directly Message-ID: <20210812092204.GB4827@lst.de> References: <20210811070542.3403116-1-jhubbard@nvidia.com> <20210811070542.3403116-4-jhubbard@nvidia.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210811070542.3403116-4-jhubbard@nvidia.com> User-Agent: Mutt/1.5.17 (2007-11-01) X-Rspamd-Queue-Id: C40975042A08 Authentication-Results: imf01.hostedemail.com; dkim=none; spf=none (imf01.hostedemail.com: domain of hch@lst.de has no SPF policy when checking 213.95.11.211) smtp.mailfrom=hch@lst.de; dmarc=none X-Rspamd-Server: rspam01 X-Stat-Signature: wnrjw314akdqf3oyw19qa3i3kpty594i X-HE-Tag: 1628760126-224633 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000018, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Wed, Aug 11, 2021 at 12:05:42AM -0700, John Hubbard wrote: > - if (unlikely(!try_get_page(page))) > + if (unlikely(try_get_compound_head(page, 1) == NULL)) Why not a simple ! instead of the == NULL? Otherwise looks good: Reviewed-by: Christoph Hellwig