sysctl: register only tables of sysctl files

Split the registration of a complex ctl_table array which may have
arbitrary numbers of directories (->child != NULL) and tables of files
into a series of simpler registrations that only register tables of files.

Graphically:

   register('dir', { + file-a
                     + file-b
                     + subdir1
                       + file-c
                     + subdir2
                       + file-d
                       + file-e })

is transformed into:
   wrapper->subheaders[0] = register('dir', {file1-a, file1-b})
   wrapper->subheaders[1] = register('dir/subdir1', {file-c})
   wrapper->subheaders[2] = register('dir/subdir2', {file-d, file-e})
   return wrapper

This guarantees that __register_sysctl_table will only see a simple
ctl_table array with all entries having (->child == NULL).

Care was taken to pass the original simple ctl_table arrays to
__register_sysctl_table whenever possible.

This change is derived from a similar patch written
by Lucrian Grijincu.

Inspired-by: Lucian Adrian Grijincu <lucian.grijincu@gmail.com>
Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>

1 files changed, 1 insertions, 1 deletions

diff --git a/include/linux/sysctl.h b/include/linux/sysctl.h
index a514e0f6056d..25c7dfe1a7ec 100644
--- a/include/linux/sysctl.h
+++ b/include/linux/sysctl.h
@@ -1015,7 +1015,7 @@ struct ctl_table
         void *data;
         int maxlen;
         umode_t mode;
-        struct ctl_table *child;
+        struct ctl_table *child;        /* Deprecated */
         struct ctl_table *parent;       /* Automatically set */
         proc_handler *proc_handler;     /* Callback for text formatting */
         struct ctl_table_poll *poll;