From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S936549AbcIFXH2 (ORCPT ); Tue, 6 Sep 2016 19:07:28 -0400 Received: from cloudserver094114.home.net.pl ([79.96.170.134]:49148 "HELO cloudserver094114.home.net.pl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S932133AbcIFXH0 (ORCPT ); Tue, 6 Sep 2016 19:07:26 -0400 From: "Rafael J. Wysocki" To: Marek Szyprowski Cc: linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org, iommu@lists.linux-foundation.org, linux-samsung-soc@vger.kernel.org, linux-arm-kernel@lists.infradead.org, Joerg Roedel , Inki Dae , Kukjin Kim , Krzysztof Kozlowski , Bartlomiej Zolnierkiewicz , Ulf Hansson , Mark Brown , Greg Kroah-Hartman Subject: Re: [PATCH v2 07/10] driver core: Add support for links to already probed drivers Date: Wed, 07 Sep 2016 01:13:23 +0200 Message-ID: <1787976.ELaxkTxS9k@vostro.rjw.lan> User-Agent: KMail/4.11.5 (Linux/4.8.0-rc2+; KDE/4.11.5; x86_64; ; ) In-Reply-To: <1466144820-6286-8-git-send-email-m.szyprowski@samsung.com> References: <1466144820-6286-1-git-send-email-m.szyprowski@samsung.com> <1466144820-6286-8-git-send-email-m.szyprowski@samsung.com> MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="utf-8" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Friday, June 17, 2016 08:26:57 AM Marek Szyprowski wrote: > Set proper link state if link is created between already probed supplier > device and to be probed consumer device. > > Signed-off-by: Marek Szyprowski > --- > drivers/base/core.c | 4 +++- > 1 file changed, 3 insertions(+), 1 deletion(-) > > diff --git a/drivers/base/core.c b/drivers/base/core.c > index 4e778539b750..d9c5c5542a6b 100644 > --- a/drivers/base/core.c > +++ b/drivers/base/core.c > @@ -125,7 +125,9 @@ struct devlink *device_link_add(struct device *consumer, > > link->flags = flags; > link->status = (flags & DEVICE_LINK_PROBE_TIME) ? > - DEVICE_LINK_CONSUMER_PROBE : DEVICE_LINK_DORMANT; > + DEVICE_LINK_CONSUMER_PROBE : > + (supplier->driver ? DEVICE_LINK_AVAILABLE : > + DEVICE_LINK_DORMANT); > spin_lock_init(&link->lock); > > /* > The supplier->driver check is insufficient and racy. It is insufficient, because supplier->driver is also set during supplier probe and the probe may still not be successful. It is racy, because supplier->driver may be modified right after this check. The only way to address the issue at hand I can see is to add a flag to indicate to device_link_add() that the supplier has already been probed successfully. Thanks, Rafael