[PATCH 1/5] driver core: do not always lock parent in shutdown

[David Jeffery <djeffery@redhat.com>]

Don't lock a parent device unless it is needed in device_shutdown. This
is in preparation for making device shutdown asynchronous, when it will
be needed to allow children of a common parent to shut down
simultaneously.

Signed-off-by: Stuart Hayes <stuart.w.hayes@gmail.com>
Signed-off-by: David Jeffery <djeffery@redhat.com>
Tested-by: Laurence Oberman <loberman@redhat.com>
---
 drivers/base/core.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/base/core.c b/drivers/base/core.c
index 791f9e444df8..eb54fc9680de 100644
--- a/drivers/base/core.c
+++ b/drivers/base/core.c
@@ -4819,7 +4819,7 @@ void device_shutdown(void)
 		spin_unlock(&devices_kset->list_lock);
 
 		/* hold lock to avoid race with probe/release */
-		if (parent)
+		if (parent && dev->bus && dev->bus->need_parent_lock)
 			device_lock(parent);
 		device_lock(dev);
 
@@ -4843,7 +4843,7 @@ void device_shutdown(void)
 		}
 
 		device_unlock(dev);
-		if (parent)
+		if (parent && dev->bus && dev->bus->need_parent_lock)
 			device_unlock(parent);
 
 		put_device(dev);
-- 
2.53.0