Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756758Ab0BJXlz (ORCPT ); Wed, 10 Feb 2010 18:41:55 -0500 Received: from hera.kernel.org ([140.211.167.34]:40420 "EHLO hera.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755831Ab0BJXly (ORCPT ); Wed, 10 Feb 2010 18:41:54 -0500 Message-ID: <4B7344A4.1030607@kernel.org> Date: Thu, 11 Feb 2010 08:43:32 +0900 From: Tejun Heo User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.1.5) Gecko/20091130 SUSE/3.0.0-1.1.1 Thunderbird/3.0 MIME-Version: 1.0 To: Miklos Szeredi CC: mszeredi@suse.cz, linux-kernel@vger.kernel.org, fuse-devel@lists.sourceforge.net, polynomial-c@gentoo.org, akpm@linux-foundation.org Subject: Re: [fuse-devel] [PATCH] FUSE/CUSE: implement direct mmap support References: <4B70FBE4.7050700@kernel.org> <4B7296DF.207@kernel.org> <4B729F07.8020704@kernel.org> <4B72A802.6040009@kernel.org> In-Reply-To: X-Enigmail-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.2.3 (hera.kernel.org [127.0.0.1]); Wed, 10 Feb 2010 23:40:59 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1081 Lines: 31 Hello, On 02/11/2010 12:02 AM, Miklos Szeredi wrote: >> Yeah, sure. FUSE server is free to give them separate regions. The >> only restriction is the SHMLBA alignment which is pretty easy to >> adhere to. > > What I really meant was: does it ever happen that mapping a *single > open file* of a chardev twice will result in two different maps? > Or will the maps be only different if it was a different open of the > device? I don't know if there is one but ->mmap() implementation is definitely allowed to do that. > If there's a pattern there, we might make the sharing/non-sharing > automated, and greatly simplify the interface. Isn't the interface pretty simple as it is? If we want to make it easier for API users by imposing limits, I think the correct layer to do that would be at the library level. Thanks. -- tejun -- 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/