PM / Runtime: Prevent runtime_resume from racing with probe
This patch (as1475) adds device_lock() and device_unlock() calls to
the store methods for the power/control and power/autosuspend_delay_ms
sysfs attribute files. We don't want badly timed writes to these
files to cause runtime_resume callbacks to occur while a driver is
being probed for a device.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
diff --git a/drivers/base/power/sysfs.c b/drivers/base/power/sysfs.c
index a9f5b89..942d6a7 100644
--- a/drivers/base/power/sysfs.c
+++ b/drivers/base/power/sysfs.c
@@ -116,12 +116,14 @@
cp = memchr(buf, '\n', n);
if (cp)
len = cp - buf;
+ device_lock(dev);
if (len == sizeof ctrl_auto - 1 && strncmp(buf, ctrl_auto, len) == 0)
pm_runtime_allow(dev);
else if (len == sizeof ctrl_on - 1 && strncmp(buf, ctrl_on, len) == 0)
pm_runtime_forbid(dev);
else
- return -EINVAL;
+ n = -EINVAL;
+ device_unlock(dev);
return n;
}
@@ -205,7 +207,9 @@
if (strict_strtol(buf, 10, &delay) != 0 || delay != (int) delay)
return -EINVAL;
+ device_lock(dev);
pm_runtime_set_autosuspend_delay(dev, delay);
+ device_unlock(dev);
return n;
}