From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 3D258E810A4 for ; Wed, 27 Sep 2023 08:08:56 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230098AbjI0IIy (ORCPT ); Wed, 27 Sep 2023 04:08:54 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43576 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229981AbjI0IIw (ORCPT ); Wed, 27 Sep 2023 04:08:52 -0400 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 29D1D13A for ; Wed, 27 Sep 2023 01:08:51 -0700 (PDT) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 56BBBC433C8; Wed, 27 Sep 2023 08:08:50 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1695802130; bh=zf6JHS267CeMrO2LV3FAJJ03uWrJ4mZGfN9wNudLAic=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=01OYMm3N7I2nQWtZbeHZ9WZ+QP1RYMQ07z/zLLlk2i/NjMAobDdNwJV6G0zJ7PRF2 oJLDmWdme+sIRlGh7qzuTISfpqqyPAGHO20yiug0ZqQEdI1kQyijDaydnLlXX2jxPn AeAOvMVGx5QLckVyUbcDp1iBe39quMGbkA18Ozgk= Date: Wed, 27 Sep 2023 10:08:47 +0200 From: Greg KH To: Zhenhua Huang Cc: rafael@kernel.org, linux-kernel@vger.kernel.org, quic_pkondeti@quicinc.com, quic_tingweiz@quicinc.com, saravanak@google.com Subject: Re: [RESEND PATCH] driver core: Clear FWNODE_FLAG_LINKS_ADDED in device_links_purge() Message-ID: <2023092724-lisp-settle-c84f@gregkh> References: <1695781810-5700-1-git-send-email-quic_zhenhuah@quicinc.com> <2023092722-proofread-vindicate-f26c@gregkh> <9f04d29e-bd83-e8c1-7e55-b5a0441abc9b@quicinc.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <9f04d29e-bd83-e8c1-7e55-b5a0441abc9b@quicinc.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Sep 27, 2023 at 02:34:43PM +0800, Zhenhua Huang wrote: > > > On 2023/9/27 13:57, Greg KH wrote: > > On Wed, Sep 27, 2023 at 10:30:10AM +0800, Zhenhua Huang wrote: > > > Flag FWNODE_FLAG_LINKS_ADDED stops fwnode links creation. Current kernel > > > only adds it once after fwnode links creation in fw_devlink_parse_fwnode(). > > > After that even device links being purged, the flag will not be cleared. > > > > > > Fwnode links are converted to device links and will not be added back > > > forever in normal case. Essentially if a device is registered and > > > unregisted (also deleted) before it is probed (due to missing fwlink > > > dependencies, abort in device_links_check_suppliers), the fwlink is not > > > setup next when device is newly created again. This means the probe gets > > > called without meeting all dependencies. > > > > > > It usuallly happens in the case of a glue driver. Of_platform_populate() > > > allows us to populate subnodes. We may do it in ancestor node probing > > > function, then check subnode's probing status because there may be chances > > > that suppliers of subnode are not ready. We may further need to do > > > of_platform_depopulate(which purges device links) and in some time > > > of_platform_populate() again. Such case we miss fwnode links(so that device > > > links) during second time of populating subnodes. > > > > > > Fix it by Clearing FWNODE_FLAG_LINKS_ADDED flag in purging device link > > > func, indicates both fwnode links and device links are absent. > > > > > > Signed-off-by: Zhenhua Huang > > > --- > > > drivers/base/core.c | 4 ++++ > > > 1 file changed, 4 insertions(+) > > > > > > diff --git a/drivers/base/core.c b/drivers/base/core.c > > > index b7d7f41..2a1975d 100644 > > > --- a/drivers/base/core.c > > > +++ b/drivers/base/core.c > > > @@ -1630,6 +1630,10 @@ static void device_links_purge(struct device *dev) > > > __device_link_del(&link->kref); > > > } > > > + /* Clear flags in fwnode. Give a chance to create fwnode link again */ > > > + if (dev->fwnode) > > > + dev->fwnode->flags &= ~FWNODE_FLAG_LINKS_ADDED; > > > + > > > device_links_write_unlock(); > > > } > > > -- > > > 2.7.4 > > > > > > > Why is this a RESEND? What was wrong with the first version? > > As per request of codes author, I CCed saravanak this time :) > Nothing else changed. Please state that below the --- line, otherwise we have no idea why this was needed, we can't read minds :) thanks, greg k-h