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=-6.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 B2366C433E7 for ; Tue, 13 Oct 2020 23:54:07 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 50EA2206D5 for ; Tue, 13 Oct 2020 23:54:07 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="08vl6rbF" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 50EA2206D5 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 E8D3F6B00F7; Tue, 13 Oct 2020 19:54:06 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id E3E736B00F8; Tue, 13 Oct 2020 19:54:06 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id D06F36B00F9; Tue, 13 Oct 2020 19:54:06 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0120.hostedemail.com [216.40.44.120]) by kanga.kvack.org (Postfix) with ESMTP id 9D7F76B00F7 for ; Tue, 13 Oct 2020 19:54:06 -0400 (EDT) Received: from smtpin07.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay04.hostedemail.com (Postfix) with ESMTP id 3E0341EF1 for ; Tue, 13 Oct 2020 23:54:06 +0000 (UTC) X-FDA: 77368558092.07.drop86_501024f27207 Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin07.hostedemail.com (Postfix) with ESMTP id 21C661803F9A2 for ; Tue, 13 Oct 2020 23:54:06 +0000 (UTC) X-HE-Tag: drop86_501024f27207 X-Filterd-Recvd-Size: 2461 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by imf01.hostedemail.com (Postfix) with ESMTP for ; Tue, 13 Oct 2020 23:54:05 +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 AE6A6221FF; Tue, 13 Oct 2020 23:54:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1602633245; bh=ZUiRUd+TI4gD8W1PQh0i+fR97qz+OJPr/OObS+O6Mug=; h=Date:From:To:Subject:In-Reply-To:From; b=08vl6rbFpJi7cdLbmDvYGAQLGjsRnbkH8jpOyx82pUxaGgpngI6AURP46WtKlRjtt 3LZWQVc/uGxn9WtxFoMiu4xwRlbecM5lDBcPsPa2QTv8rc241PF17BFfbMf0joehf2 zjD5ONeQoXN2ONGXs4tzm/K5veEKKLkxJeMJki08= Date: Tue, 13 Oct 2020 16:54:04 -0700 From: Andrew Morton To: akpm@linux-foundation.org, linux-mm@kvack.org, mm-commits@vger.kernel.org, richard.weiyang@linux.alibaba.com, torvalds@linux-foundation.org Subject: [patch 104/181] mm/mmap: not necessary to check mapping separately Message-ID: <20201013235404.3mjS9F61G%akpm@linux-foundation.org> In-Reply-To: <20201013164658.3bfd96cc224d8923e66a9f4e@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: Wei Yang Subject: mm/mmap: not necessary to check mapping separately *root* with type of struct rb_root_cached is an element of *mapping* with type of struct address_space. This implies when we have a valid *root* it must be a part of valid *mapping*. So we can merge these two checks together to make the code more easy to read and to save some cpu cycles. Link: https://lkml.kernel.org/r/20200913133631.37781-1-richard.weiyang@linux.alibaba.com Signed-off-by: Wei Yang Reviewed-by: Andrew Morton Signed-off-by: Andrew Morton --- mm/mmap.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) --- a/mm/mmap.c~mm-mmap-not-necessary-to-check-mapping-separately +++ a/mm/mmap.c @@ -895,10 +895,9 @@ again: anon_vma_interval_tree_post_update_vma(next); anon_vma_unlock_write(anon_vma); } - if (mapping) - i_mmap_unlock_write(mapping); if (root) { + i_mmap_unlock_write(mapping); uprobe_mmap(vma); if (adjust_next) _