[PATCH net 1/3] dpll: export __dpll_device_change_ntf() for use under dpll_lock

[Ivan Vecera <ivecera@redhat.com>]

Export __dpll_device_change_ntf() so that drivers can send device
change notifications from within device callbacks, which are already
called under dpll_lock. Using dpll_device_change_ntf() in that
context would deadlock.

Add lockdep_assert_held() to catch misuse without the lock held.

Signed-off-by: Ivan Vecera <ivecera@redhat.com>
---
 drivers/dpll/dpll_netlink.c | 13 +++++++++++--
 include/linux/dpll.h        |  1 +
 2 files changed, 12 insertions(+), 2 deletions(-)

diff --git a/drivers/dpll/dpll_netlink.c b/drivers/dpll/dpll_netlink.c
index 0ff1658c2dc1..75e3ae0c16d0 100644
--- a/drivers/dpll/dpll_netlink.c
+++ b/drivers/dpll/dpll_netlink.c
@@ -829,12 +829,21 @@ int dpll_device_delete_ntf(struct dpll_device *dpll)
 	return dpll_device_event_send(DPLL_CMD_DEVICE_DELETE_NTF, dpll);
 }
 
-static int
-__dpll_device_change_ntf(struct dpll_device *dpll)
+/**
+ * __dpll_device_change_ntf - notify that the dpll device has been changed
+ * @dpll: registered dpll pointer
+ *
+ * Context: caller must hold dpll_lock. Suitable for use inside device
+ *          callbacks which are already invoked under dpll_lock.
+ * Return: 0 if succeeds, error code otherwise.
+ */
+int __dpll_device_change_ntf(struct dpll_device *dpll)
 {
+	lockdep_assert_held(&dpll_lock);
 	dpll_device_notify(dpll, DPLL_DEVICE_CHANGED);
 	return dpll_device_event_send(DPLL_CMD_DEVICE_CHANGE_NTF, dpll);
 }
+EXPORT_SYMBOL_GPL(__dpll_device_change_ntf);
 
 /**
  * dpll_device_change_ntf - notify that the dpll device has been changed
diff --git a/include/linux/dpll.h b/include/linux/dpll.h
index f8037f1ab20b..2dbe8567eafc 100644
--- a/include/linux/dpll.h
+++ b/include/linux/dpll.h
@@ -284,6 +284,7 @@ void dpll_pin_on_pin_unregister(struct dpll_pin *parent, struct dpll_pin *pin,
 int dpll_pin_ref_sync_pair_add(struct dpll_pin *pin,
 			       struct dpll_pin *ref_sync_pin);
 
+int __dpll_device_change_ntf(struct dpll_device *dpll);
 int dpll_device_change_ntf(struct dpll_device *dpll);
 
 int __dpll_pin_change_ntf(struct dpll_pin *pin);
-- 
2.53.0