fs/btrfs/rcu-string.h

   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