From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wm0-f71.google.com (mail-wm0-f71.google.com [74.125.82.71]) by kanga.kvack.org (Postfix) with ESMTP id C34CD6B026D for ; Wed, 16 Nov 2016 09:43:07 -0500 (EST) Received: by mail-wm0-f71.google.com with SMTP id u144so26209011wmu.1 for ; Wed, 16 Nov 2016 06:43:07 -0800 (PST) Received: from mx2.suse.de (mx2.suse.de. [195.135.220.15]) by mx.google.com with ESMTPS id v5si7511800wme.84.2016.11.16.06.43.06 for (version=TLS1 cipher=AES128-SHA bits=128/128); Wed, 16 Nov 2016 06:43:06 -0800 (PST) Date: Wed, 16 Nov 2016 15:43:03 +0100 From: Jan Kara Subject: Re: [PATCH 11/21] mm: Remove unnecessary vma->vm_ops check Message-ID: <20161116144303.GP21785@quack2.suse.cz> References: <1478233517-3571-1-git-send-email-jack@suse.cz> <1478233517-3571-12-git-send-email-jack@suse.cz> <20161115222819.GK23021@node> <20161116132918.GK21785@quack2.suse.cz> <20161116142755.GA28051@node.shutemov.name> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20161116142755.GA28051@node.shutemov.name> Sender: owner-linux-mm@kvack.org List-ID: To: "Kirill A. Shutemov" Cc: Jan Kara , linux-mm@kvack.org, linux-fsdevel@vger.kernel.org, linux-nvdimm@lists.01.org, Andrew Morton , Ross Zwisler , "Kirill A. Shutemov" On Wed 16-11-16 17:27:55, Kirill A. Shutemov wrote: > On Wed, Nov 16, 2016 at 02:29:18PM +0100, Jan Kara wrote: > > On Wed 16-11-16 01:28:19, Kirill A. Shutemov wrote: > > > On Fri, Nov 04, 2016 at 05:25:07AM +0100, Jan Kara wrote: > > > > We don't check whether vma->vm_ops is NULL in do_shared_fault() so > > > > there's hardly any point in checking it in wp_page_shared() or > > > > wp_pfn_shared() which get called only for shared file mappings as well. > > > > > > > > Signed-off-by: Jan Kara > > > > > > Well, I'm not sure about this. > > > > > > do_shared_fault() doesn't have the check since we checked it upper by > > > stack: see vma_is_anonymous() in handle_pte_fault(). > > > > > > In principal, it should be fine. But random crappy driver has potential to > > > blow it up. > > > > Ok, so do you prefer me to keep this patch or discard it? Either is fine with > > me. It was just a cleanup I wrote when factoring out the functionality. > > I would rather drop it. > > Eventually, we need to make sure that all file-backed vma has vm_ops. > I tried to do this once, but that back-fired... OK, will do. Honza -- Jan Kara SUSE Labs, CR -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org