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=-3.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS 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 8A58FC432C0 for ; Sun, 1 Dec 2019 01:49:53 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 509FE2086A for ; Sun, 1 Dec 2019 01:49:53 +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 509FE2086A 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) Received: by kanga.kvack.org (Postfix, from userid 40) id F24E96B0277; Sat, 30 Nov 2019 20:49:52 -0500 (EST) 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-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-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, _