fs/btrfs/rcu-string.h

   1 /*
   2  * Copyright (C) 2012 Red Hat.  All rights reserved.
   3  *
   4  * This program is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU General Public
   6  * License v2 as published by the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  11  * General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU General Public
  14  * License along with this program; if not, write to the
  15  * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  16  * Boston, MA 021110-1307, USA.
  17  */
  18
  19 struct rcu_string {
  20         struct rcu_head rcu;
  21         char str[0];
  22 };
  23
  24 static inline struct rcu_string *rcu_string_strdup(const char *src, gfp_t mask)
  25 {
  26         size_t len = strlen(src) + 1;
  27         struct rcu_string *ret = kzalloc(sizeof(struct rcu_string) +
  28                                          (len * sizeof(char)), mask);
  29         if (!ret)
  30                 return ret;
  31         strncpy(ret->str, src, len);
  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 })