Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1763672AbXK2RHB (ORCPT ); Thu, 29 Nov 2007 12:07:01 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1756542AbXK2RGw (ORCPT ); Thu, 29 Nov 2007 12:06:52 -0500 Received: from iolanthe.rowland.org ([192.131.102.54]:35403 "HELO iolanthe.rowland.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1762177AbXK2RGv (ORCPT ); Thu, 29 Nov 2007 12:06:51 -0500 Date: Thu, 29 Nov 2007 12:06:50 -0500 (EST) From: Alan Stern X-X-Sender: stern@iolanthe.rowland.org To: Kay Sievers cc: Cornelia Huck , Greg KH , Kernel development list , Jonathan Corbet , Randy Dunlap Subject: Re: [PATCH] kobject: make sure kobj->ktype is set before kobject_init In-Reply-To: <1196352280.3118.11.camel@lov.site> Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1669 Lines: 39 On Thu, 29 Nov 2007, Kay Sievers wrote: > > In fact, if we were designing the kobject API from scratch, I'd suggest > > making the ktype value an argument to kobject_init() so that it > > _couldn't_ be omitted. > > Sounds fine, maybe we should also pass the name along, so it will be > obvious what happens here: > int kobject_init(struct kobject *kobj, struct kobj_type *type, const char *fmt, ...) I don't know... Normally *_init() routines can't fail, but this could. Then things like device_register() would run into trouble: The caller wouldn't know whether a failure occurred before or after the kobject_init() call, so it wouldn't know what sort of cleanup action was needed: kfree() or device_put(). > Oh, if you want to rewind on error and have an initialized but still > unregistered kobject, and just want to free the allocated name by > calling kobject_cleanup() or kobject_put() you might not expect, that > your whole object that embeds the kobject will be gone. Just something > we need to document ... When that sort of thing happens, the unwinding should be done by the code responsible for whole object. For example, if device_add() fails then the caller should go on to call device_put() rather than kfree(dev). That's how you would expect things to work in most cases. There aren't many bare kobjects in the kernel. I agree that documenting this behavior would be good. Alan Stern - 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/