From patchwork Sun Dec 1 01:49:50 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andrew Morton X-Patchwork-Id: 11268205 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id C81F6112B for ; Sun, 1 Dec 2019 01:49:54 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 9658E2086A for ; Sun, 1 Dec 2019 01:49:54 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="c+2wDuLq" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 9658E2086A Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linux-foundation.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 02FA66B0276; Sat, 30 Nov 2019 20:49:53 -0500 (EST) Delivered-To: linux-mm-outgoing@kvack.org Received: by kanga.kvack.org (Postfix, from userid 40) id F24E96B0277; Sat, 30 Nov 2019 20:49:52 -0500 (EST) X-Original-To: int-list-linux-mm@kvack.org X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id DE99F6B0278; Sat, 30 Nov 2019 20:49:52 -0500 (EST) X-Original-To: linux-mm@kvack.org X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0049.hostedemail.com [216.40.44.49]) by kanga.kvack.org (Postfix) with ESMTP id C14276B0276 for ; Sat, 30 Nov 2019 20:49:52 -0500 (EST) Received: from smtpin20.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay04.hostedemail.com (Postfix) with SMTP id 78EBE40C0 for ; Sun, 1 Dec 2019 01:49:52 +0000 (UTC) X-FDA: 76214891424.20.crime34_9062d5e7a151e X-Spam-Summary: 2,0,0,548079aa493183ce,d41d8cd98f00b204,akpm@linux-foundation.org,:akpm@linux-foundation.org:ira.weiny@intel.com:jhubbard@nvidia.com::mm-commits@vger.kernel.org:torvalds@linux-foundation.org:vbabka@suse.cz:zhongjiang@huawei.com,RULES_HIT:41:355:379:800:960:967:973:988:989:1260:1263:1345:1381:1431:1437:1534:1542:1711:1730:1747:1777:1792:2198:2199:2393:2525:2559:2563:2682:2685:2859:2902:2933:2937:2939:2942:2945:2947:2951:2954:3022:3138:3139:3140:3141:3142:3352:3865:3866:3867:3868:3870:3872:3874:3934:3936:3938:3941:3944:3947:3950:3953:3956:3959:4250:4321:5007:6261:6653:7576:8531:9025:9391:9545:10004:10913:11026:11658:11914:12043:12048:12296:12297:12438:12517:12519:12555:12679:12783:12986:13255:13846:14096:14181:14721:14849:21080:21212:21433:21451:21627:21819:21939:30054:30064:30070,0,RBL:error,CacheIP:none,Bayesian:0.5,0.5,0.5,Netcheck:none,DomainCache:0,MSF:not bulk,SPF:fp,MSBL:0,DNSBL:neutral,Custom_rules:0:0:0,LFtime:3,LUA_SUMMARY:none X-HE-Tag: crime34_9062d5e7a151e X-Filterd-Recvd-Size: 3326 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by imf07.hostedemail.com (Postfix) with ESMTP for ; Sun, 1 Dec 2019 01:49:52 +0000 (UTC) Received: from localhost.localdomain (c-73-231-172-41.hsd1.ca.comcast.net [73.231.172.41]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 19AB4208E4; Sun, 1 Dec 2019 01:49:51 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1575164991; bh=7Sw3eEIus75nQFpmr1T1WuXKYQavg0WAU7PdxGnIHNI=; h=Date:From:To:Subject:From; b=c+2wDuLqXyx/oQRs9od9mJRCpZEVhlMfKjCsn7DxnhteWbT4TH6QQ+h7yFztW938b YFrYz39nO4mg4spI+YJ51kb6eHji+zS+xuatiZa6AIrg51m5zyLo6L8iLqRt32HYSg awJBCopw87sS9oHki5zJU82SoI1Wg+SRoPRHebKw= Date: Sat, 30 Nov 2019 17:49:50 -0800 From: akpm@linux-foundation.org To: akpm@linux-foundation.org, ira.weiny@intel.com, jhubbard@nvidia.com, linux-mm@kvack.org, mm-commits@vger.kernel.org, torvalds@linux-foundation.org, vbabka@suse.cz, zhongjiang@huawei.com Subject: [patch 014/158] mm/gup.c: allow CMA migration to propagate errors back to caller Message-ID: <20191201014950.8xby9TJPA%akpm@linux-foundation.org> User-Agent: s-nail v14.8.16 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: From: zhong jiang Subject: mm/gup.c: allow CMA migration to propagate errors back to caller check_and_migrate_cma_pages() was recording the result of __get_user_pages_locked() in an unsigned "nr_pages" variable. Because __get_user_pages_locked() returns a signed value that can include negative errno values, this had the effect of hiding errors. Change check_and_migrate_cma_pages() implementation so that it uses a signed variable instead, and propagates the results back to the caller just as other gup internal functions do. This was discovered with the help of unsigned_lesser_than_zero.cocci. Link: http://lkml.kernel.org/r/1571671030-58029-1-git-send-email-zhongjiang@huawei.com Signed-off-by: zhong jiang Suggested-by: John Hubbard Acked-by: Vlastimil Babka Reviewed-by: John Hubbard Reviewed-by: Ira Weiny Signed-off-by: Andrew Morton --- mm/gup.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) --- a/mm/gup.c~mm-gup-allow-cma-migration-to-propagate-errors-back-to-caller +++ a/mm/gup.c @@ -1443,6 +1443,7 @@ static long check_and_migrate_cma_pages( bool drain_allow = true; bool migrate_allow = true; LIST_HEAD(cma_page_list); + long ret = nr_pages; check_again: for (i = 0; i < nr_pages;) { @@ -1504,17 +1505,18 @@ check_again: * again migrating any new CMA pages which we failed to isolate * earlier. */ - nr_pages = __get_user_pages_locked(tsk, mm, start, nr_pages, + ret = __get_user_pages_locked(tsk, mm, start, nr_pages, pages, vmas, NULL, gup_flags); - if ((nr_pages > 0) && migrate_allow) { + if ((ret > 0) && migrate_allow) { + nr_pages = ret; drain_allow = true; goto check_again; } } - return nr_pages; + return ret; } #else static long check_and_migrate_cma_pages(struct task_struct *tsk,