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1/* SPDX-License-Identifier: GPL-2.0 */2/*3 * Copyright (C) 2012 Red Hat. All rights reserved.4 */5 6#ifndef BTRFS_RCU_STRING_H7#define BTRFS_RCU_STRING_H8 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#endif59