From mboxrd@z Thu Jan 1 00:00:00 1970 From: "H. Peter Anvin" Subject: Re: [RFC][PATCH 1/3] Move parts of init_dev() into new functions Date: Mon, 25 Aug 2008 15:21:38 -0700 Message-ID: <48B33072.4080509@zytor.com> References: <20080825201110.GA32440@us.ibm.com> <20080825211146.70b4af63@lxorguk.ukuu.org.uk> <20080825220125.GA1084@us.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20080825220125.GA1084-r/Jw6+rmf7HQT0dZR+AlfA@public.gmane.org> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: containers-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org Errors-To: containers-bounces-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org To: sukadev-r/Jw6+rmf7HQT0dZR+AlfA@public.gmane.org Cc: kyle-hoO6YkzgTuCM0SS3m2neIg@public.gmane.org, bastian-yyjItF7Rl6lg9hUCZPvPmw@public.gmane.org, containers-qjLDD68F18O7TbgM5vRIOg@public.gmane.org, xemul-GEFAQzZX7r8dnm+yROfE0A@public.gmane.org, Alan Cox , ebiederm-aS9lmoZGLiVWk0Htik3J/w@public.gmane.org List-Id: containers.vger.kernel.org sukadev-r/Jw6+rmf7HQT0dZR+AlfA@public.gmane.org wrote: > > By extension, maybe the tty layer would need another interface to determine > the instance: > > instance = driver->ops->get_instance(driver, inode, other_stuff) > > using this we find the tty > > tty = driver->ops->something(driver, instance, idx); This seems more than a bit redundant. The "instance", IMO, *is* the tty structure; so the interface should be: tty = driver->ops->get_tty(driver, inode [, other_stuff?]); Not "index", but "inode". If, as a courtesy to the generic driver, we want to precalculate the index number we can do that, but otherwise that is of course available as: index = inode->i_rdev - MK_DEV(device->major, device->minor_start); ... and if we replaced device->{major,minor_start} with device->base and made the drivers use MK_DEV() in the initializers, it would be even simpler. -hpa