From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755497AbaHFKNV (ORCPT ); Wed, 6 Aug 2014 06:13:21 -0400 Received: from mta-out1.inet.fi ([62.71.2.230]:38923 "EHLO jenni2.inet.fi" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754329AbaHFKNU (ORCPT ); Wed, 6 Aug 2014 06:13:20 -0400 Date: Wed, 6 Aug 2014 13:12:45 +0300 From: "Kirill A. Shutemov" To: Oleg Nesterov Cc: Andrew Morton , Alexander Viro , Cyrill Gorcunov , David Howells , "David S. Miller" , "Eric W. Biederman" , "Kirill A. Shutemov" , Peter Zijlstra , Sasha Levin , linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH v2 5/7] fs/proc/task_mmu.c: simplify the vma_stop() logic Message-ID: <20140806101245.GA30703@node.dhcp.inet.fi> References: <20140805194627.GA30693@redhat.com> <20140805194659.GA30736@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20140805194659.GA30736@redhat.com> User-Agent: Mutt/1.5.22.1 (2013-10-16) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Aug 05, 2014 at 09:46:59PM +0200, Oleg Nesterov wrote: > m_start() drops ->mmap_sem and does mmput() if it retuns vsyscall > vma. This is because in this case m_stop()->vma_stop() obviously > can't use gate_vma->vm_mm. > > Now that we have proc_maps_private->mm we can simplify this logic: > > - Change m_start() to return with ->mmap_sem held unless it returns > IS_ERR_OR_NULL(). > > - Change vma_stop() to use priv->mm and avoid the ugly vma checks, > this makes "vm_area_struct *vma" unnecessary. > > - This also allows m_start() to use vm_stop(). > > - Cleanup m_next() to follow the new locking rule. > > Note: m_stop() looks very ugly, and this temporary uglifies it > even more. Fixed by the next change. > > Signed-off-by: Oleg Nesterov Acked-by: Kirill A. Shutemov -- Kirill A. Shutemov