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
15 struct rcu_string {
16 struct rcu_head rcu;
17 char str[];
18 };
19
20 static 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(ret);
30 return NULL;
31 }
32 return ret;
33 }
34
35 static 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
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