lkml.org 
[lkml]   [2011]   [May]   [18]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Subject[PATCH 1/2] of: fix race when matching drivers
From
Date
From: Milton Miller <miltonm@bga.com>

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 <mroos@linux.ee>
Signed-off-by: Milton Miller <miltonm@bga.com>
[grant.likely: modified to only call of_match_device() once]
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
---
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);


\
 
 \ /
  Last update: 2011-05-18 21:23    [from the cache]
©2003-2014 Jasper Spaans. hosted at Digital Ocean