media: v4l: subdev: Add a function to lock two sub-device states, use it

Add two new functions, v4l2_subdev_lock_states() and
v4l2_subdev_unclock_states(), to acquire and release the state of two
sub-devices. They differ from calling v4l2_subdev_{un,}lock_state() so
that if the two states share the same lock, the lock is acquired only
once.

Also use the new functions in v4l2_subdev_link_validate().

Signed-off-by: Sakari Ailus <[email protected]>
Reviewed-by: Julien Massot <[email protected]>
Reviewed-by: Laurent Pinchart <[email protected]>
Signed-off-by: Hans Verkuil <[email protected]>

0 files changed, 0 insertions, 0 deletions