1/* SPDX-License-Identifier: GPL-2.0 */
2/*
3 * Copyright (C) 2012 Red Hat. All rights reserved.
4 */
5
6#ifndef BTRFS_RCU_STRING_H
7#define BTRFS_RCU_STRING_H
8
9#include <linux/types.h>
10#include <linux/string.h>
11#include <linux/slab.h>
12#include <linux/rcupdate.h>
13#include <linux/printk.h>
14
15struct rcu_string {
16 struct rcu_head rcu;
17 char str[];
18};
19
20static inline struct rcu_string *rcu_string_strdup(const char *src, gfp_t mask)
21{
22 size_t len = strlen(src) + 1;
23 struct rcu_string *ret = kzalloc(sizeof(struct rcu_string) +
24 (len * sizeof(char)), mask);
25 if (!ret)
26 return ret;
27 /* Warn if the source got unexpectedly truncated. */
28 if (WARN_ON(strscpy(ret->str, src, len) < 0)) {
29 kfree(objp: ret);
30 return NULL;
31 }
32 return ret;
33}
34
35static inline void rcu_string_free(struct rcu_string *str)
36{
37 if (str)
38 kfree_rcu(str, rcu);
39}
40
41#define printk_in_rcu(fmt, ...) do { \
42 rcu_read_lock(); \
43 printk(fmt, __VA_ARGS__); \
44 rcu_read_unlock(); \
45} while (0)
46
47#define printk_ratelimited_in_rcu(fmt, ...) do { \
48 rcu_read_lock(); \
49 printk_ratelimited(fmt, __VA_ARGS__); \
50 rcu_read_unlock(); \
51} while (0)
52
53#define rcu_str_deref(rcu_str) ({ \
54 struct rcu_string *__str = rcu_dereference(rcu_str); \
55 __str->str; \
56})
57
58#endif
59

source code of linux/fs/btrfs/rcu-string.h