LXR linux/kernel/rcu.h

   1/*
   2 * Read-Copy Update definitions shared among RCU implementations.
   3 *
   4 * This program is free software; you can redistribute it and/or modify
   5 * it under the terms of the GNU General Public License as published by
   6 * the Free Software Foundation; either version 2 of the License, or
   7 * (at your option) any later version.
   8 *
   9 * This program is distributed in the hope that it will be useful,
  10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12 * GNU General Public License for more details.
  13 *
  14 * You should have received a copy of the GNU General Public License
  15 * along with this program; if not, write to the Free Software
  16 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
  17 *
  18 * Copyright IBM Corporation, 2011
  19 *
  20 * Author: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
  21 */
  22
  23#ifndef __LINUX_RCU_H
  24#define __LINUX_RCU_H
  25
  26#ifdef CONFIG_RCU_TRACE
  27#define RCU_TRACE(stmt) stmt
  28#else /* #ifdef CONFIG_RCU_TRACE */
  29#define RCU_TRACE(stmt)
  30#endif /* #else #ifdef CONFIG_RCU_TRACE */
  31
  32/*
  33 * debug_rcu_head_queue()/debug_rcu_head_unqueue() are used internally
  34 * by call_rcu() and rcu callback execution, and are therefore not part of the
  35 * RCU API. Leaving in rcupdate.h because they are used by all RCU flavors.
  36 */
  37
  38#ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD
  39# define STATE_RCU_HEAD_READY   0
  40# define STATE_RCU_HEAD_QUEUED  1
  41
  42extern struct debug_obj_descr rcuhead_debug_descr;
  43
  44static inline void debug_rcu_head_queue(struct rcu_head *head)
  45{
  46        WARN_ON_ONCE((unsigned long)head & 0x3);
  47        debug_object_activate(head, &rcuhead_debug_descr);
  48        debug_object_active_state(head, &rcuhead_debug_descr,
  49                                  STATE_RCU_HEAD_READY,
  50                                  STATE_RCU_HEAD_QUEUED);
  51}
  52
  53static inline void debug_rcu_head_unqueue(struct rcu_head *head)
  54{
  55        debug_object_active_state(head, &rcuhead_debug_descr,
  56                                  STATE_RCU_HEAD_QUEUED,
  57                                  STATE_RCU_HEAD_READY);
  58        debug_object_deactivate(head, &rcuhead_debug_descr);
  59}
  60#else   /* !CONFIG_DEBUG_OBJECTS_RCU_HEAD */
  61static inline void debug_rcu_head_queue(struct rcu_head *head)
  62{
  63}
  64
  65static inline void debug_rcu_head_unqueue(struct rcu_head *head)
  66{
  67}
  68#endif  /* #else !CONFIG_DEBUG_OBJECTS_RCU_HEAD */
  69
  70extern void kfree(const void *);
  71
  72static inline void __rcu_reclaim(char *rn, struct rcu_head *head)
  73{
  74        unsigned long offset = (unsigned long)head->func;
  75
  76        if (__is_kfree_rcu_offset(offset)) {
  77                RCU_TRACE(trace_rcu_invoke_kfree_callback(rn, head, offset));
  78                kfree((void *)head - offset);
  79        } else {
  80                RCU_TRACE(trace_rcu_invoke_callback(rn, head));
  81                head->func(head);
  82        }
  83}
  84
  85#endif /* __LINUX_RCU_H */
  86