sysctl: replace child with an enumeration

This is part of the effort to remove the empty element at the end of
ctl_table structs. "child" was a deprecated elem in this struct and was
being used to differentiate between two types of ctl_tables: "normal"
and "permanently emtpy".

What changed?:
* Replace "child" with an enumeration that will have two values: the
  default (0) and the permanently empty (1). The latter is left at zero
  so when struct ctl_table is created with kzalloc or in a local
  context, it will have the zero value by default. We document the
  new enum with kdoc.
* Remove the "empty child" check from sysctl_check_table
* Remove count_subheaders function as there is no longer a need to
  calculate how many headers there are for every child
* Remove the recursive call to unregister_sysctl_table as there is no
  need to traverse down the child tree any longer
* Add a new SYSCTL_PERM_EMPTY_DIR binary flag
* Remove the last remanence of child from partport/procfs.c

Signed-off-by: Joel Granados <j.granados@samsung.com>
Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>

1 files changed, 0 insertions, 1 deletions

diff --git a/drivers/parport/procfs.c b/drivers/parport/procfs.c
index 0f2d2e1ee28e3..4e5b972c3e263 100644
--- a/drivers/parport/procfs.c
+++ b/drivers/parport/procfs.c
@@ -387,7 +387,6 @@ parport_device_sysctl_template = {
 			.data		= NULL,
 			.maxlen		= 0,
 			.mode		= 0555,
-			.child		= NULL
 		},
 		{}
 	}