Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757050AbYHMSUM (ORCPT ); Wed, 13 Aug 2008 14:20:12 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751545AbYHMSUA (ORCPT ); Wed, 13 Aug 2008 14:20:00 -0400 Received: from bombadil.infradead.org ([18.85.46.34]:60606 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751373AbYHMST7 (ORCPT ); Wed, 13 Aug 2008 14:19:59 -0400 Date: Wed, 13 Aug 2008 11:18:50 -0700 From: Greg KH To: Marcin Obara Cc: linux-kernel@vger.kernel.org Subject: Re: [PATCH] Intel Management Engine Interface Message-ID: <20080813181850.GD4886@kroah.com> References: <20080813005835.GE22793@kroah.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.16 (2007-06-09) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1302 Lines: 44 On Wed, Aug 13, 2008 at 08:16:02AM +0100, Marcin Obara wrote: > 2008/8/13 Greg KH : > > On Mon, Aug 11, 2008 at 09:23:01PM +0200, Marcin Obara wrote: > >> +/* IOCTL commands */ > >> +#define IOCTL_HECI_GET_VERSION \ > >> + _IOWR('H' , 0x0, struct heci_message_data) > > > > This can easily be a sysfs file, why not do that instead? > > > sysfs file would require additional file handle used by every userspace client. So, is that really a great overhead? > GET_VERSION is called frequently Why? Shouldn't it only be called once? >, and sysfs file would create extra overhead. Have you measured it? > With ioctl - only one file handle is used, and userspace client logic > is simpler. But the kernel is messier and we are trying to not add any more ioctls to it. Especially for trivial things like the version number of the hardware device. > Normal flow looks like: > > open > ioctl(GET_VERSION) Great, do an additional open/read/close here for the version, I think you will find it pretty trivial to do :) thanks, greg k-h -- 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/