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(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