From patchwork Fri Apr 30 05:55:41 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andrew Morton X-Patchwork-Id: 12232379 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=-15.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 51543C433ED for ; Fri, 30 Apr 2021 05:55:44 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id F130561464 for ; Fri, 30 Apr 2021 05:55:43 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org F130561464 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 959376B00AF; Fri, 30 Apr 2021 01:55:43 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 8F4CC6B00B0; Fri, 30 Apr 2021 01:55:43 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 783D66B00B1; Fri, 30 Apr 2021 01:55:43 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0087.hostedemail.com [216.40.44.87]) by kanga.kvack.org (Postfix) with ESMTP id 4F24D6B00AF for ; Fri, 30 Apr 2021 01:55:43 -0400 (EDT) Received: from smtpin28.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay05.hostedemail.com (Postfix) with ESMTP id 146CF181AF5C3 for ; Fri, 30 Apr 2021 05:55:43 +0000 (UTC) X-FDA: 78087971766.28.69491CA Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by imf19.hostedemail.com (Postfix) with ESMTP id 520EF90009EF for ; Fri, 30 Apr 2021 05:55:12 +0000 (UTC) Received: by mail.kernel.org (Postfix) with ESMTPSA id EAA9F61463; Fri, 30 Apr 2021 05:55:41 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1619762142; bh=Jo+jYjLuKCde1tu6xch80s7EpfWHARAp6UsrZijywSM=; h=Date:From:To:Subject:In-Reply-To:From; b=sPbC8YBv4a1l9IBCOWJYntZ2SL1F3D2+ePKy0oBK2xmIBWxqWdVyNGaZSpuUibLO9 y5uLHnX36BBzXF0QIVKB/2TNhTQbZU9OEqp+PezIFpXLzkqfY+TODcECIvSr6VfFJ/ 7WN+HIhrntS0Vck/qfk2AzoG12abwm4tmGlYQxoE= Date: Thu, 29 Apr 2021 22:55:41 -0700 From: Andrew Morton To: akpm@linux-foundation.org, linux-mm@kvack.org, mm-commits@vger.kernel.org, sh1r4s3@mail.si-head.nl, torvalds@linux-foundation.org, vbabka@suse.cz Subject: [patch 049/178] mm/msync: exit early when the flags is an MS_ASYNC and start < vm_start Message-ID: <20210430055541.k_Y51wMDK%akpm@linux-foundation.org> In-Reply-To: <20210429225251.02b6386d21b69255b4f6c163@linux-foundation.org> User-Agent: s-nail v14.8.16 Authentication-Results: imf19.hostedemail.com; dkim=pass header.d=linux-foundation.org header.s=korg header.b=sPbC8YBv; spf=pass (imf19.hostedemail.com: domain of akpm@linux-foundation.org designates 198.145.29.99 as permitted sender) smtp.mailfrom=akpm@linux-foundation.org; dmarc=none X-Rspamd-Server: rspam01 X-Rspamd-Queue-Id: 520EF90009EF X-Stat-Signature: mruuofe6amkbg9zs3uoi16ji3t5hx3xb Received-SPF: none (linux-foundation.org>: No applicable sender policy available) receiver=imf19; identity=mailfrom; envelope-from=""; helo=mail.kernel.org; client-ip=198.145.29.99 X-HE-DKIM-Result: pass/pass X-HE-Tag: 1619762112-800147 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: Nikita Ermakov Subject: mm/msync: exit early when the flags is an MS_ASYNC and start < vm_start If an unmapped region was found and the flag is MS_ASYNC (without MS_INVALIDATE) there is nothing to do and the result would be always -ENOMEM, so return immediately. Link: https://lkml.kernel.org/r/20201025092901.56399-1-sh1r4s3@mail.si-head.nl Signed-off-by: Nikita Ermakov Cc: Vlastimil Babka Signed-off-by: Andrew Morton --- mm/msync.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) --- a/mm/msync.c~mm-msync-exit-early-when-the-flags-is-an-ms_async-and-start-vm_start +++ a/mm/msync.c @@ -55,7 +55,9 @@ SYSCALL_DEFINE3(msync, unsigned long, st goto out; /* * If the interval [start,end) covers some unmapped address ranges, - * just ignore them, but return -ENOMEM at the end. + * just ignore them, but return -ENOMEM at the end. Besides, if the + * flag is MS_ASYNC (w/o MS_INVALIDATE) the result would be -ENOMEM + * anyway and there is nothing left to do, so return immediately. */ mmap_read_lock(mm); vma = find_vma(mm, start); @@ -69,6 +71,8 @@ SYSCALL_DEFINE3(msync, unsigned long, st goto out_unlock; /* Here start < vma->vm_end. */ if (start < vma->vm_start) { + if (flags == MS_ASYNC) + goto out_unlock; start = vma->vm_start; if (start >= end) goto out_unlock;