nstree: switch to new structures

Switch the nstree management to the new combined structures.

Link: https://patch.msgid.link/20251110-work-namespace-nstree-fixes-v1-5-e8a9264e0fb9@kernel.org
Signed-off-by: Christian Brauner <brauner@kernel.org>

4 files changed, 54 insertions, 45 deletions

diff --git a/include/linux/ns/ns_common_types.h b/include/linux/ns/ns_common_types.h
index ccd1d1e116f6..b332b019b29c 100644
--- a/include/linux/ns/ns_common_types.h
+++ b/include/linux/ns/ns_common_types.h
@@ -3,6 +3,7 @@
 #define _LINUX_NS_COMMON_TYPES_H
 
 #include <linux/atomic.h>
+#include <linux/ns/nstree_types.h>
 #include <linux/rbtree.h>
 #include <linux/refcount.h>
 #include <linux/types.h>
@@ -98,6 +99,13 @@ extern const struct proc_ns_operations utsns_operations;
  * Initial namespaces:
  *   Boot-time namespaces (init_net, init_pid_ns, etc.) start with
  *   __ns_ref_active = 1 and remain active forever.
+ *
+ * @ns_type: type of namespace (e.g., CLONE_NEWNET)
+ * @stashed: cached dentry to be used by the vfs
+ * @ops: namespace operations
+ * @inum: namespace inode number (quickly recycled for non-initial namespaces)
+ * @__ns_ref: main reference count (do not use directly)
+ * @ns_tree: namespace tree nodes and active reference count
  */
 struct ns_common {
 	u32 ns_type;
@@ -106,24 +114,7 @@ struct ns_common {
 	unsigned int inum;
 	refcount_t __ns_ref; /* do not use directly */
 	union {
-		struct {
-			u64 ns_id;
-			struct /* global namespace rbtree and list */ {
-				struct rb_node ns_unified_tree_node;
-				struct list_head ns_unified_list_node;
-			};
-			struct /* per type rbtree and list */ {
-				struct rb_node ns_tree_node;
-				struct list_head ns_list_node;
-			};
-			struct /* namespace ownership rbtree and list */ {
-				struct rb_root ns_owner_tree; /* rbtree of namespaces owned by this namespace */
-				struct list_head ns_owner; /* list of namespaces owned by this namespace */
-				struct rb_node ns_owner_tree_node; /* node in the owner namespace's rbtree */
-				struct list_head ns_owner_entry; /* node in the owner namespace's ns_owned list */
-			};
-			atomic_t __ns_ref_active; /* do not use directly */
-		};
+		struct ns_tree;
 		struct rcu_head ns_rcu;
 	};
 };
diff --git a/include/linux/ns/nstree_types.h b/include/linux/ns/nstree_types.h
index 6ee0c39686f8..2fb28ee31efb 100644
--- a/include/linux/ns/nstree_types.h
+++ b/include/linux/ns/nstree_types.h
@@ -33,4 +33,23 @@ struct ns_tree_node {
 	struct list_head ns_list_entry;
 };
 
+/**
+ * struct ns_tree - Namespace tree nodes and active reference count
+ * @ns_id: Unique namespace identifier
+ * @__ns_ref_active: Active reference count (do not use directly)
+ * @ns_unified_node: Node in the global namespace tree
+ * @ns_tree_node: Node in the per-type namespace tree
+ * @ns_owner_node: Node in the owner namespace's tree of owned namespaces
+ * @ns_owner_root: Root of the tree of namespaces owned by this namespace
+ *                 (only used when this namespace is an owner)
+ */
+struct ns_tree {
+	u64 ns_id;
+	atomic_t __ns_ref_active;
+	struct ns_tree_node ns_unified_node;
+	struct ns_tree_node ns_tree_node;
+	struct ns_tree_node ns_owner_node;
+	struct ns_tree_root ns_owner_root;
+};
+
 #endif /* _LINUX_NSTREE_TYPES_H */
diff --git a/include/linux/ns_common.h b/include/linux/ns_common.h
index 6a4ca8c3b9c4..f90509ee0900 100644
--- a/include/linux/ns_common.h
+++ b/include/linux/ns_common.h
@@ -26,20 +26,19 @@ static __always_inline bool is_ns_init_id(const struct ns_common *ns)
 	return ns->ns_id <= NS_LAST_INIT_ID;
 }
 
-
-#define NS_COMMON_INIT(nsname, refs)							\
-{											\
-	.ns_type		= ns_common_type(&nsname),				\
-	.ns_id			= ns_init_id(&nsname),					\
-	.inum			= ns_init_inum(&nsname),				\
-	.ops			= to_ns_operations(&nsname),				\
-	.stashed		= NULL,							\
-	.__ns_ref		= REFCOUNT_INIT(refs),					\
-	.__ns_ref_active	= ATOMIC_INIT(1),					\
-	.ns_list_node		= LIST_HEAD_INIT(nsname.ns.ns_list_node),		\
-	.ns_owner_entry		= LIST_HEAD_INIT(nsname.ns.ns_owner_entry),		\
-	.ns_owner		= LIST_HEAD_INIT(nsname.ns.ns_owner),			\
-	.ns_unified_list_node	= LIST_HEAD_INIT(nsname.ns.ns_unified_list_node),	\
+#define NS_COMMON_INIT(nsname, refs)									\
+{													\
+	.ns_type			= ns_common_type(&nsname),					\
+	.ns_id				= ns_init_id(&nsname),						\
+	.inum				= ns_init_inum(&nsname),					\
+	.ops				= to_ns_operations(&nsname),					\
+	.stashed			= NULL,								\
+	.__ns_ref			= REFCOUNT_INIT(refs),						\
+	.__ns_ref_active		= ATOMIC_INIT(1),						\
+	.ns_unified_node.ns_list_entry	= LIST_HEAD_INIT(nsname.ns.ns_unified_node.ns_list_entry),	\
+	.ns_tree_node.ns_list_entry	= LIST_HEAD_INIT(nsname.ns.ns_tree_node.ns_list_entry),		\
+	.ns_owner_node.ns_list_entry	= LIST_HEAD_INIT(nsname.ns.ns_owner_node.ns_list_entry),	\
+	.ns_owner_root.ns_list_head	= LIST_HEAD_INIT(nsname.ns.ns_owner_root.ns_list_head),		\
 }
 
 #define ns_common_init(__ns)                     \
diff --git a/include/linux/nstree.h b/include/linux/nstree.h
index 98b848cf2f1c..175e4625bfa6 100644
--- a/include/linux/nstree.h
+++ b/include/linux/nstree.h
@@ -13,14 +13,14 @@
 
 struct ns_common;
 
-extern struct ns_tree cgroup_ns_tree;
-extern struct ns_tree ipc_ns_tree;
-extern struct ns_tree mnt_ns_tree;
-extern struct ns_tree net_ns_tree;
-extern struct ns_tree pid_ns_tree;
-extern struct ns_tree time_ns_tree;
-extern struct ns_tree user_ns_tree;
-extern struct ns_tree uts_ns_tree;
+extern struct ns_tree_root cgroup_ns_tree;
+extern struct ns_tree_root ipc_ns_tree;
+extern struct ns_tree_root mnt_ns_tree;
+extern struct ns_tree_root net_ns_tree;
+extern struct ns_tree_root pid_ns_tree;
+extern struct ns_tree_root time_ns_tree;
+extern struct ns_tree_root user_ns_tree;
+extern struct ns_tree_root uts_ns_tree;
 
 void ns_tree_node_init(struct ns_tree_node *node);
 void ns_tree_root_init(struct ns_tree_root *root);
@@ -46,14 +46,14 @@ void ns_tree_node_del(struct ns_tree_node *node, struct ns_tree_root *root);
 			 (((__ns) == ns_init_ns(__ns)) ? ns_init_id(__ns) : 0))
 
 u64 __ns_tree_gen_id(struct ns_common *ns, u64 id);
-void __ns_tree_add_raw(struct ns_common *ns, struct ns_tree *ns_tree);
-void __ns_tree_remove(struct ns_common *ns, struct ns_tree *ns_tree);
+void __ns_tree_add_raw(struct ns_common *ns, struct ns_tree_root *ns_tree);
+void __ns_tree_remove(struct ns_common *ns, struct ns_tree_root *ns_tree);
 struct ns_common *ns_tree_lookup_rcu(u64 ns_id, int ns_type);
 struct ns_common *__ns_tree_adjoined_rcu(struct ns_common *ns,
-					 struct ns_tree *ns_tree,
+					 struct ns_tree_root *ns_tree,
 					 bool previous);
 
-static inline void __ns_tree_add(struct ns_common *ns, struct ns_tree *ns_tree, u64 id)
+static inline void __ns_tree_add(struct ns_common *ns, struct ns_tree_root *ns_tree, u64 id)
 {
 	__ns_tree_gen_id(ns, id);
 	__ns_tree_add_raw(ns, ns_tree);
@@ -91,6 +91,6 @@ static inline void __ns_tree_add(struct ns_common *ns, struct ns_tree *ns_tree,
 #define ns_tree_adjoined_rcu(__ns, __previous) \
 	__ns_tree_adjoined_rcu(to_ns_common(__ns), to_ns_tree(__ns), __previous)
 
-#define ns_tree_active(__ns) (!RB_EMPTY_NODE(&to_ns_common(__ns)->ns_tree_node))
+#define ns_tree_active(__ns) (!RB_EMPTY_NODE(&to_ns_common(__ns)->ns_tree_node.ns_node))
 
 #endif /* _LINUX_NSTREE_H */