Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753535AbaLNXIN (ORCPT ); Sun, 14 Dec 2014 18:08:13 -0500 Received: from kanga.kvack.org ([205.233.56.17]:57820 "EHLO kanga.kvack.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752230AbaLNXIK (ORCPT ); Sun, 14 Dec 2014 18:08:10 -0500 Date: Sun, 14 Dec 2014 18:08:09 -0500 From: Benjamin LaHaise To: "Kirill A. Shutemov" Cc: Andrew Morton , Linus Torvalds , linux-aio@kvack.org, Linux Kernel , linux-mm , Pavel Emelyanov , Dmitry Monakhov Subject: Re: [GIT PULL] aio: changes for 3.19 Message-ID: <20141214230809.GK2672@kvack.org> References: <20141214202224.GH2672@kvack.org> <20141214215221.GI2672@kvack.org> <20141214141336.a0267e95.akpm@linux-foundation.org> <20141214230208.GA9217@node.dhcp.inet.fi> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20141214230208.GA9217@node.dhcp.inet.fi> User-Agent: Mutt/1.4.2.2i Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Dec 15, 2014 at 01:02:08AM +0200, Kirill A. Shutemov wrote: > But it seems the problem is bigger than what the patch fixes. To me we are > too permisive on what vma can be remapped. > > How can we know that it's okay to move vma around for random driver which > provide .mmap? Or I miss something obvious? Most drivers do not care if a vma is moved within the virtual address space of a process. The aio ring buffer is special in that it gets unmapped when userspace does an io_destroy(), and io_destroy() has to know what the address is moved to in order to perform the unmap. Normal drivers don't perform the unmap themselves. -ben -- "Thought is the essence of where you are now." -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/