From 01294d82622d6d9d64bde8e4530c7e2c6dbb6ee6 Mon Sep 17 00:00:00 2001 From: Milton Miller Date: Wed, 18 May 2011 10:27:39 -0500 Subject: [PATCH] of: fix race when matching drivers 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 file changed, 6 insertions(+), 2 deletions(-) diff --git a/include/linux/of_device.h b/include/linux/of_device.h index 8bfe6c1d4365..b33d68814a73 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); -- 2.20.1