Commit 01294d82 authored by Milton Miller's avatar Milton Miller Committed by Grant Likely

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: default avatarMeelis Roos <mroos@linux.ee>
Signed-off-by: default avatarMilton Miller <miltonm@bga.com>
[grant.likely: modified to only call of_match_device() once]
Signed-off-by: default avatarGrant Likely <grant.likely@secretlab.ca>
parent 2e9521fd
...@@ -21,8 +21,12 @@ extern void of_device_make_bus_id(struct device *dev); ...@@ -21,8 +21,12 @@ extern void of_device_make_bus_id(struct device *dev);
static inline int of_driver_match_device(struct device *dev, static inline int of_driver_match_device(struct device *dev,
const struct device_driver *drv) const struct device_driver *drv)
{ {
dev->of_match = of_match_device(drv->of_match_table, dev); const struct of_device_id *match;
return dev->of_match != NULL;
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); extern struct platform_device *of_dev_get(struct platform_device *dev);
......
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