tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
nstree: add helper to operate on struct ns_tree_{node,root}
Add helpers that work on the combined rbtree and rculist combined.
This will make the code a lot more managable and legible.
Link: https://patch.msgid.link/20251110-work-namespace-nstree-fixes-v1-4-e8a9264e0fb9@kernel.org
Signed-off-by: Christian Brauner <brauner@kernel.org>
+93
+8
include/linux/nstree.h
+8
include/linux/nstree.h
···
22
22
extern struct ns_tree user_ns_tree;
23
23
extern struct ns_tree uts_ns_tree;
24
24
25
+
void ns_tree_node_init(struct ns_tree_node *node);
26
+
void ns_tree_root_init(struct ns_tree_root *root);
27
+
bool ns_tree_node_empty(const struct ns_tree_node *node);
28
+
struct rb_node *ns_tree_node_add(struct ns_tree_node *node,
29
+
struct ns_tree_root *root,
30
+
int (*cmp)(struct rb_node *, const struct rb_node *));
31
+
void ns_tree_node_del(struct ns_tree_node *node, struct ns_tree_root *root);
32
+
25
33
#define to_ns_tree(__ns) \
26
34
_Generic((__ns), \
27
35
struct cgroup_namespace *: &(cgroup_ns_tree), \
+85
kernel/nstree.c
+85
kernel/nstree.c
···
73
73
.type = CLONE_NEWTIME,
74
74
};
75
75
76
+
/**
77
+
* ns_tree_node_init - Initialize a namespace tree node
78
+
* @node: The node to initialize
79
+
*
80
+
* Initializes both the rbtree node and list entry.
81
+
*/
82
+
void ns_tree_node_init(struct ns_tree_node *node)
83
+
{
84
+
RB_CLEAR_NODE(&node->ns_node);
85
+
INIT_LIST_HEAD(&node->ns_list_entry);
86
+
}
87
+
88
+
/**
89
+
* ns_tree_root_init - Initialize a namespace tree root
90
+
* @root: The root to initialize
91
+
*
92
+
* Initializes both the rbtree root and list head.
93
+
*/
94
+
void ns_tree_root_init(struct ns_tree_root *root)
95
+
{
96
+
root->ns_rb = RB_ROOT;
97
+
INIT_LIST_HEAD(&root->ns_list_head);
98
+
}
99
+
100
+
/**
101
+
* ns_tree_node_empty - Check if a namespace tree node is empty
102
+
* @node: The node to check
103
+
*
104
+
* Returns true if the node is not in any tree.
105
+
*/
106
+
bool ns_tree_node_empty(const struct ns_tree_node *node)
107
+
{
108
+
return RB_EMPTY_NODE(&node->ns_node);
109
+
}
110
+
111
+
/**
112
+
* ns_tree_node_add - Add a node to a namespace tree
113
+
* @node: The node to add
114
+
* @root: The tree root to add to
115
+
* @cmp: Comparison function for rbtree insertion
116
+
*
117
+
* Adds the node to both the rbtree and the list, maintaining sorted order.
118
+
* The list is maintained in the same order as the rbtree to enable efficient
119
+
* iteration.
120
+
*
121
+
* Returns: NULL if insertion succeeded, existing node if duplicate found
122
+
*/
123
+
struct rb_node *ns_tree_node_add(struct ns_tree_node *node,
124
+
struct ns_tree_root *root,
125
+
int (*cmp)(struct rb_node *, const struct rb_node *))
126
+
{
127
+
struct rb_node *ret, *prev;
128
+
129
+
/* Add to rbtree */
130
+
ret = rb_find_add_rcu(&node->ns_node, &root->ns_rb, cmp);
131
+
132
+
/* Add to list in sorted order */
133
+
prev = rb_prev(&node->ns_node);
134
+
if (!prev) {
135
+
/* No previous node, add at head */
136
+
list_add_rcu(&node->ns_list_entry, &root->ns_list_head);
137
+
} else {
138
+
/* Add after previous node */
139
+
struct ns_tree_node *prev_node;
140
+
prev_node = rb_entry(prev, struct ns_tree_node, ns_node);
141
+
list_add_rcu(&node->ns_list_entry, &prev_node->ns_list_entry);
142
+
}
143
+
144
+
return ret;
145
+
}
146
+
147
+
/**
148
+
* ns_tree_node_del - Remove a node from a namespace tree
149
+
* @node: The node to remove
150
+
* @root: The tree root to remove from
151
+
*
152
+
* Removes the node from both the rbtree and the list atomically.
153
+
*/
154
+
void ns_tree_node_del(struct ns_tree_node *node, struct ns_tree_root *root)
155
+
{
156
+
rb_erase(&node->ns_node, &root->ns_rb);
157
+
RB_CLEAR_NODE(&node->ns_node);
158
+
list_bidir_del_rcu(&node->ns_list_entry);
159
+
}
160
+
76
161
static inline struct ns_common *node_to_ns(const struct rb_node *node)
77
162
{
78
163
if (!node)