From patchwork Mon Jun 1 11:55:21 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Miaohe Lin X-Patchwork-Id: 11581895 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 482CF739 for ; Mon, 1 Jun 2020 11:51:57 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 2F193206E2 for ; Mon, 1 Jun 2020 11:51:57 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726078AbgFALvx (ORCPT ); Mon, 1 Jun 2020 07:51:53 -0400 Received: from szxga06-in.huawei.com ([45.249.212.32]:56728 "EHLO huawei.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1725838AbgFALvx (ORCPT ); Mon, 1 Jun 2020 07:51:53 -0400 Received: from DGGEMS408-HUB.china.huawei.com (unknown [172.30.72.59]) by Forcepoint Email with ESMTP id 9DE07D15174F6FB97AB7; Mon, 1 Jun 2020 19:51:51 +0800 (CST) Received: from huawei.com (10.175.101.6) by DGGEMS408-HUB.china.huawei.com (10.3.19.208) with Microsoft SMTP Server id 14.3.487.0; Mon, 1 Jun 2020 19:51:44 +0800 From: linmiaohe To: CC: , , Subject: [PATCH] userfaultfd: eliminate meaningless check in userfaultfd_register() Date: Mon, 1 Jun 2020 19:55:21 +0800 Message-ID: <1591012521-517-1-git-send-email-linmiaohe@huawei.com> X-Mailer: git-send-email 1.8.3.1 MIME-Version: 1.0 X-Originating-IP: [10.175.101.6] X-CFilter-Loop: Reflected Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org From: Miaohe Lin When we reach here, !(cur->vm_flags & VM_MAYWRITE) is already checked and equals to false. So the condition here always equals to false and should be eliminated. Signed-off-by: Miaohe Lin --- fs/userfaultfd.c | 2 -- 1 file changed, 2 deletions(-) diff --git a/fs/userfaultfd.c b/fs/userfaultfd.c index e39fdec8a0b0..e529e6bbb57b 100644 --- a/fs/userfaultfd.c +++ b/fs/userfaultfd.c @@ -1409,8 +1409,6 @@ static int userfaultfd_register(struct userfaultfd_ctx *ctx, if (end & (vma_hpagesize - 1)) goto out_unlock; } - if ((vm_flags & VM_UFFD_WP) && !(cur->vm_flags & VM_MAYWRITE)) - goto out_unlock; /* * Check that this vma isn't already owned by a