driver core: Add a guard() definition for the device_lock()

At present there are ~200 usages of device_lock() in the kernel. Some of
those usages lead to "goto unlock;" patterns which have proven to be
error prone. Define a "device" guard() definition to allow for those to
be cleaned up and prevent new ones from appearing.

Link: http://lore.kernel.org/r/657897453dda8_269bd29492@dwillia2-mobl3.amr.corp.intel.com.notmuch
Link: http://lore.kernel.org/r/[email protected]
Cc: Vishal Verma <[email protected]>
Cc: Ira Weiny <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Greg Kroah-Hartman <[email protected]>
Cc: Andrew Morton <[email protected]>
Signed-off-by: Dan Williams <[email protected]>
Reviewed-by: Ira Weiny <[email protected]>
Reviewed-by: Dave Jiang <[email protected]>
Reviewed-by: Vishal Verma <[email protected]>
Link: https://lore.kernel.org/r/170250854466.1522182.17555361077409628655.stgit@dwillia2-xfh.jf.intel.com
Signed-off-by: Greg Kroah-Hartman <[email protected]>

Author: djbw

include/linux/device.h

@@ -1007,6 +1007,8 @@ static inline void device_unlock(struct device *dev)
 	mutex_unlock(&dev->mutex);
 }
 
+DEFINE_GUARD(device, struct device *, device_lock(_T), device_unlock(_T))
+
 static inline void device_lock_assert(struct device *dev)
 {
 	lockdep_assert_held(&dev->mutex);