From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933742Ab1ERTVK (ORCPT ); Wed, 18 May 2011 15:21:10 -0400 Received: from mail-px0-f173.google.com ([209.85.212.173]:51444 "EHLO mail-px0-f173.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933723Ab1ERTVC (ORCPT ); Wed, 18 May 2011 15:21:02 -0400 Subject: [PATCH 1/2] of: fix race when matching drivers To: devicetree-discuss@lists.ozlabs.org, gregkh@suse.de, linux-kernel@vger.kernel.org, Milton Miller , sparclinux@vger.kernel.org, Linus Torvalds , David Miller , Josip Rodin From: Grant Likely Date: Wed, 18 May 2011 13:21:00 -0600 Message-ID: <20110518192100.28986.94335.stgit@ponder> In-Reply-To: <20110518185751.28986.69446.stgit@ponder> References: <20110518185751.28986.69446.stgit@ponder> User-Agent: StGit/0.15 MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Milton Miller If two drivers are probing devices at the same time, both will write their match table result to the dev->of_match cache at the same time. Only write the result if the device matches. In a thread titled "SBus devices sometimes detected, sometimes not", Meelis reported his SBus hme was not detected about 50% of the time. >>From the debug suggested by Grant it was obvious another driver matched some devices between the call to match the hme and the hme discovery failling. Reported-by: Meelis Roos Signed-off-by: Milton Miller [grant.likely: modified to only call of_match_device() once] Signed-off-by: Grant Likely --- include/linux/of_device.h | 8 ++++++-- 1 files changed, 6 insertions(+), 2 deletions(-) diff --git a/include/linux/of_device.h b/include/linux/of_device.h index 8bfe6c1..b33d688 100644 --- a/include/linux/of_device.h +++ b/include/linux/of_device.h @@ -21,8 +21,12 @@ extern void of_device_make_bus_id(struct device *dev); static inline int of_driver_match_device(struct device *dev, const struct device_driver *drv) { - dev->of_match = of_match_device(drv->of_match_table, dev); - return dev->of_match != NULL; + const struct of_device_id *match; + + match = of_match_device(drv->of_match_table, dev); + if (match) + dev->of_match = match; + return match != NULL; } extern struct platform_device *of_dev_get(struct platform_device *dev);