Unverified Commit 560e25e7 authored by Christian Brauner's avatar Christian Brauner
Browse files

nstree: add unified namespace list 

Allow to walk the unified namespace list completely locklessly.

Link: https://patch.msgid.link/20251029-work-namespace-nstree-listns-v4-18-2e6f823ebdc0@kernel.org


Signed-off-by: default avatarChristian Brauner <brauner@kernel.org>
parent a202a500

include/linux/ns_common.h

+2 −0
Original line number Diff line number Diff line
@@ -111,6 +111,7 @@ struct ns_common { 
			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;
@@ -224,6 +225,7 @@ static __always_inline bool is_initial_namespace(struct ns_common *ns) 
	.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(__ns)                     \

kernel/nscommon.c

+1 −0
Original line number Diff line number Diff line
@@ -65,6 +65,7 @@ int __ns_common_init(struct ns_common *ns, u32 ns_type, const struct proc_ns_ope 
	RB_CLEAR_NODE(&ns->ns_unified_tree_node);

	RB_CLEAR_NODE(&ns->ns_owner_tree_node);

	INIT_LIST_HEAD(&ns->ns_list_node);

	INIT_LIST_HEAD(&ns->ns_unified_list_node);

	ns->ns_owner_tree = RB_ROOT;

	INIT_LIST_HEAD(&ns->ns_owner);

	INIT_LIST_HEAD(&ns->ns_owner_entry);

kernel/nstree.c

+12 −1
Original line number Diff line number Diff line
@@ -9,6 +9,7 @@ 


static __cacheline_aligned_in_smp DEFINE_SEQLOCK(ns_tree_lock);

static struct rb_root ns_unified_tree = RB_ROOT; /* protected by ns_tree_lock */

static LIST_HEAD(ns_unified_list); /* protected by ns_tree_lock */



/**

 * struct ns_tree - Namespace tree
@@ -137,7 +138,13 @@ void __ns_tree_add_raw(struct ns_common *ns, struct ns_tree *ns_tree) 
	else

		list_add_rcu(&ns->ns_list_node, &node_to_ns(prev)->ns_list_node);



	/* Add to unified tree and list */

	rb_find_add_rcu(&ns->ns_unified_tree_node, &ns_unified_tree, ns_cmp_unified);

	prev = rb_prev(&ns->ns_unified_tree_node);

	if (!prev)

		list_add_rcu(&ns->ns_unified_list_node, &ns_unified_list);

	else

		list_add_rcu(&ns->ns_unified_list_node, &node_to_ns_unified(prev)->ns_unified_list_node);



	if (ops) {

		struct user_namespace *user_ns;
@@ -186,11 +193,15 @@ void __ns_tree_remove(struct ns_common *ns, struct ns_tree *ns_tree) 


	write_seqlock(&ns_tree_lock);

	rb_erase(&ns->ns_tree_node, &ns_tree->ns_tree);

	rb_erase(&ns->ns_unified_tree_node, &ns_unified_tree);

	RB_CLEAR_NODE(&ns->ns_tree_node);



	list_bidir_del_rcu(&ns->ns_list_node);



	rb_erase(&ns->ns_unified_tree_node, &ns_unified_tree);

	RB_CLEAR_NODE(&ns->ns_unified_tree_node);



	list_bidir_del_rcu(&ns->ns_unified_list_node);



	/* Remove from owner's rbtree if this namespace has an owner */

	if (ops) {

		user_ns = ops->owner(ns);