Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1761995AbZCYPP3 (ORCPT ); Wed, 25 Mar 2009 11:15:29 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754116AbZCYPPM (ORCPT ); Wed, 25 Mar 2009 11:15:12 -0400 Received: from wf-out-1314.google.com ([209.85.200.168]:10223 "EHLO wf-out-1314.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751068AbZCYPPL convert rfc822-to-8bit (ORCPT ); Wed, 25 Mar 2009 11:15:11 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :cc:content-type:content-transfer-encoding; b=C83Olj2dUgklY3AEp8bLFiYIyFpA6b6WXFOUPYlD+9G5rdFzYRmxTgAkf/bTOKyA9i c2wKjT4qOCDsPwszXQ2gq/jipsli25LX54+DMyyXw/Y6ym9wOv8ve+FUuym9ANJ7NGLu qvFDMJ6N3QvoMK6pE24d1EVcuWv/56G7nGmDY= MIME-Version: 1.0 In-Reply-To: References: <1232458448-4412-1-git-send-email-tom.leiming@gmail.com> Date: Wed, 25 Mar 2009 23:15:09 +0800 Message-ID: Subject: Re: [PATCH] driver core: check bus->match without holding device lock From: Ming Lei To: Guennadi Liakhovetski Cc: kay.sievers@vrfy.org, Greg KH , linux-kernel@vger.kernel.org, arjan@linux.intel.com Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 8BIT Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2037 Lines: 65 2009/3/25 Guennadi Liakhovetski : > On Wed, 25 Mar 2009, Ming Lei wrote: > >> >> > Now, without .match() no probing is done. Is this an intended change and >> >> > soc-camera has to be fixed or is this a bug? >> >> >> >> It is not a driver-core bug, and soc-camera should be fixed. >> > >> > So, you're saying this used to be a bug and it has been fixed by this >> > patch? Then why isn't this mentioned in the commit message? The commit >> > text seems to suggest, that this patch shouldn't introduce any change in >> > behaviour, but it does. So, before .match == NULL lead to .probe() being >> > called, and now it doesn't anymore? >> >> Where is soc-camera ?driver in kernel tree? > > drivers/media/video/soc_camera.c > >> Which bus ?is soc-camera device (driver) attached to ? > > camera bus. > >> Why doesn't soc-camera ?driver ?have a match method? > > Why should it? Because there is only one driver on this bus by definition > (and I only register a device on the bus when I find a match between a > device and its parent / driver). I grep the drivers directory ( grep -r -n -I -A 5 -w "struct bus_type" ./* ) and find soc-camera is the __only__ bus-type which have not implemented match method, so it is better to define a match method(always return true) in soc-camera to solve the problem, OK? Also, I will submit a patch to warn absence of match (maybe should return failed) in bus_register(). > > What I in any case see wrong with this patch, is that it _silently_ > changes kernel behaviour without even mentioning it in the commit log! IMHO, the change should be reasonable, but it is missed carelessly in commit log. Thanks > > Thanks > Guennadi > --- > Guennadi Liakhovetski, Ph.D. > Freelance Open-Source Software Developer > -- Lei Ming -- 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/