[PATCH net v6 1/2] dpll: export __dpll_pin_change_ntf() for use under dpll_lock

[Petr Oros <poros@redhat.com>]

From: Ivan Vecera <ivecera@redhat.com>

Export __dpll_pin_change_ntf() so that drivers can send pin change
notifications from within pin callbacks, which are already called
under dpll_lock. Using dpll_pin_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>
Signed-off-by: Petr Oros <poros@redhat.com>
---
 drivers/dpll/dpll_netlink.c | 10 ++++++++++
 drivers/dpll/dpll_netlink.h |  2 --
 include/linux/dpll.h        |  1 +
 3 files changed, 11 insertions(+), 2 deletions(-)

diff --git a/drivers/dpll/dpll_netlink.c b/drivers/dpll/dpll_netlink.c
index 83cbd64abf5a47..95ae786e98aab3 100644
--- a/drivers/dpll/dpll_netlink.c
+++ b/drivers/dpll/dpll_netlink.c
@@ -842,11 +842,21 @@ int dpll_pin_delete_ntf(struct dpll_pin *pin)
 	return dpll_pin_event_send(DPLL_CMD_PIN_DELETE_NTF, pin);
 }
 
+/**
+ * __dpll_pin_change_ntf - notify that the pin has been changed
+ * @pin: registered pin pointer
+ *
+ * Context: caller must hold dpll_lock. Suitable for use inside pin
+ *          callbacks which are already invoked under dpll_lock.
+ * Return: 0 if succeeds, error code otherwise.
+ */
 int __dpll_pin_change_ntf(struct dpll_pin *pin)
 {
+	lockdep_assert_held(&dpll_lock);
 	dpll_pin_notify(pin, DPLL_PIN_CHANGED);
 	return dpll_pin_event_send(DPLL_CMD_PIN_CHANGE_NTF, pin);
 }
+EXPORT_SYMBOL_GPL(__dpll_pin_change_ntf);
 
 /**
  * dpll_pin_change_ntf - notify that the pin has been changed
diff --git a/drivers/dpll/dpll_netlink.h b/drivers/dpll/dpll_netlink.h
index dd28b56d27c56d..a9cfd55f57fc42 100644
--- a/drivers/dpll/dpll_netlink.h
+++ b/drivers/dpll/dpll_netlink.h
@@ -11,5 +11,3 @@ int dpll_device_delete_ntf(struct dpll_device *dpll);
 int dpll_pin_create_ntf(struct dpll_pin *pin);
 
 int dpll_pin_delete_ntf(struct dpll_pin *pin);
-
-int __dpll_pin_change_ntf(struct dpll_pin *pin);
diff --git a/include/linux/dpll.h b/include/linux/dpll.h
index 2ce295b46b8cdc..8f97120ee7b37d 100644
--- a/include/linux/dpll.h
+++ b/include/linux/dpll.h
@@ -276,6 +276,7 @@ int dpll_pin_ref_sync_pair_add(struct dpll_pin *pin,
 
 int dpll_device_change_ntf(struct dpll_device *dpll);
 
+int __dpll_pin_change_ntf(struct dpll_pin *pin);
 int dpll_pin_change_ntf(struct dpll_pin *pin);
 
 int register_dpll_notifier(struct notifier_block *nb);
-- 
2.52.0