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
9struct rcu_string {
10 struct rcu_head rcu;
11 char str[];
12};
13
14static inline struct rcu_string *rcu_string_strdup(const char *src, gfp_t mask)
15{
16 size_t len = strlen(src) + 1;
17 struct rcu_string *ret = kzalloc(size: sizeof(struct rcu_string) +
18 (len * sizeof(char)), flags: mask);
19 if (!ret)
20 return ret;
21 /* Warn if the source got unexpectedly truncated. */
22 if (WARN_ON(strscpy(ret->str, src, len) < 0)) {
23 kfree(objp: ret);
24 return NULL;
25 }
26 return ret;
27}
28
29static inline void rcu_string_free(struct rcu_string *str)
30{
31 if (str)
32 kfree_rcu(str, rcu);
33}
34
35#define printk_in_rcu(fmt, ...) do { \
36 rcu_read_lock(); \
37 printk(fmt, __VA_ARGS__); \
38 rcu_read_unlock(); \
39} while (0)
40
41#define printk_ratelimited_in_rcu(fmt, ...) do { \
42 rcu_read_lock(); \
43 printk_ratelimited(fmt, __VA_ARGS__); \
44 rcu_read_unlock(); \
45} while (0)
46
47#define rcu_str_deref(rcu_str) ({ \
48 struct rcu_string *__str = rcu_dereference(rcu_str); \
49 __str->str; \
50})
51
52#endif
53

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