[PATCH] beginning of sysctl cleanup - ctl_table_set

New object: set of sysctls [currently - root and per-net-ns].
Contains: pointer to parent set, list of tables and "should I see this set?"
method (->is_seen(set)).
Current lists of tables are subsumed by that; net-ns contains such a beast.
->lookup() for ctl_table_root returns pointer to ctl_table_set instead of
that to ->list of that ctl_table_set.

[folded compile fixes by rdd for configs without sysctl]

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

1 files changed, 31 insertions, 10 deletions

diff --git a/kernel/sysctl.c b/kernel/sysctl.c
index 35a50db9b6ce..8ee4a0619fbb 100644
--- a/kernel/sysctl.c
+++ b/kernel/sysctl.c
@@ -160,12 +160,13 @@ static struct ctl_table root_table[];
 static struct ctl_table_root sysctl_table_root;
 static struct ctl_table_header root_table_header = {
         .ctl_table = root_table,
-        .ctl_entry = LIST_HEAD_INIT(sysctl_table_root.header_list),
+        .ctl_entry = LIST_HEAD_INIT(sysctl_table_root.default_set.list),
         .root = &sysctl_table_root,
+        .set = &sysctl_table_root.default_set,
 };
 static struct ctl_table_root sysctl_table_root = {
         .root_list = LIST_HEAD_INIT(sysctl_table_root.root_list),
-        .header_list = LIST_HEAD_INIT(root_table_header.ctl_entry),
+        .default_set.list = LIST_HEAD_INIT(root_table_header.ctl_entry),
 };
 
 static struct ctl_table kern_table[];
@@ -1403,14 +1404,20 @@ void sysctl_head_finish(struct ctl_table_header *head)
         spin_unlock(&sysctl_lock);
 }
 
+static struct ctl_table_set *
+lookup_header_set(struct ctl_table_root *root, struct nsproxy *namespaces)
+{
+        struct ctl_table_set *set = &root->default_set;
+        if (root->lookup)
+                set = root->lookup(root, namespaces);
+        return set;
+}
+
 static struct list_head *
 lookup_header_list(struct ctl_table_root *root, struct nsproxy *namespaces)
 {
-        struct list_head *header_list;
-        header_list = &root->header_list;
-        if (root->lookup)
-                header_list = root->lookup(root, namespaces);
-        return header_list;
+        struct ctl_table_set *set = lookup_header_set(root, namespaces);
+        return &set->list;
 }
 
 struct ctl_table_header *__sysctl_head_next(struct nsproxy *namespaces,
@@ -1720,7 +1727,6 @@ struct ctl_table_header *__register_sysctl_paths(
         struct nsproxy *namespaces,
         const struct ctl_path *path, struct ctl_table *table)
 {
-        struct list_head *header_list;
         struct ctl_table_header *header;
         struct ctl_table *new, **prevp;
         unsigned int n, npath;
@@ -1772,8 +1778,8 @@ struct ctl_table_header *__register_sysctl_paths(
         }
 #endif
         spin_lock(&sysctl_lock);
-        header_list = lookup_header_list(root, namespaces);
-        list_add_tail(&header->ctl_entry, header_list);
+        header->set = lookup_header_set(root, namespaces);
+        list_add_tail(&header->ctl_entry, &header->set->list);
         spin_unlock(&sysctl_lock);
 
         return header;
@@ -1832,6 +1838,15 @@ void unregister_sysctl_table(struct ctl_table_header * header)
         kfree(header);
 }
 
+void setup_sysctl_set(struct ctl_table_set *p,
+        struct ctl_table_set *parent,
+        int (*is_seen)(struct ctl_table_set *))
+{
+        INIT_LIST_HEAD(&p->list);
+        p->parent = parent ? parent : &sysctl_table_root.default_set;
+        p->is_seen = is_seen;
+}
+
 #else /* !CONFIG_SYSCTL */
 struct ctl_table_header *register_sysctl_table(struct ctl_table * table)
 {
@@ -1848,6 +1863,12 @@ void unregister_sysctl_table(struct ctl_table_header * table)
 {
 }
 
+void setup_sysctl_set(struct ctl_table_set *p,
+        struct ctl_table_set *parent,
+        int (*is_seen)(struct ctl_table_set *))
+{
+}
+
 #endif /* CONFIG_SYSCTL */
 
 /*