rcu: Add lockdep-enabled variants of rcu_dereference()

[deliverable/linux.git] / include / linux / rcupdate.h

diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h
index e3d37efe270329c3fa6222a9ac7ec995708cd53a..839d296a7ac0268071d32409745c2ea734c9b78c 100644 (file)
--- a/include/linux/rcupdate.h
+++ b/include/linux/rcupdate.h
@@ -184,12 +184,12 @@ static inline int rcu_read_lock_sched_held(void)
        ({ \
                if (debug_locks) \
                        WARN_ON_ONCE(!(c)); \
-               rcu_dereference(p); \
+               rcu_dereference_raw(p); \
        })
 
 #else /* #ifdef CONFIG_PROVE_RCU */
 
-#define rcu_dereference_check(p, c)    rcu_dereference(p)
+#define rcu_dereference_check(p, c)    rcu_dereference_raw(p)
 
 #endif /* #else #ifdef CONFIG_PROVE_RCU */
 
@@ -325,21 +325,48 @@ static inline notrace void rcu_read_unlock_sched_notrace(void)
 
 
 /**
- * rcu_dereference - fetch an RCU-protected pointer in an
- * RCU read-side critical section.  This pointer may later
- * be safely dereferenced.
+ * rcu_dereference_raw - fetch an RCU-protected pointer
+ *
+ * The caller must be within some flavor of RCU read-side critical
+ * section, or must be otherwise preventing the pointer from changing,
+ * for example, by holding an appropriate lock.  This pointer may later
+ * be safely dereferenced.  It is the caller's responsibility to have
+ * done the right thing, as this primitive does no checking of any kind.
  *
  * Inserts memory barriers on architectures that require them
  * (currently only the Alpha), and, more importantly, documents
  * exactly which pointers are protected by RCU.
  */
-
-#define rcu_dereference(p)     ({ \
+#define rcu_dereference_raw(p) ({ \
                                typeof(p) _________p1 = ACCESS_ONCE(p); \
                                smp_read_barrier_depends(); \
                                (_________p1); \
                                })
 
+/**
+ * rcu_dereference - fetch an RCU-protected pointer, checking for RCU
+ *
+ * Makes rcu_dereference_check() do the dirty work.
+ */
+#define rcu_dereference(p) \
+       rcu_dereference_check(p, rcu_read_lock_held())
+
+/**
+ * rcu_dereference_bh - fetch an RCU-protected pointer, checking for RCU-bh
+ *
+ * Makes rcu_dereference_check() do the dirty work.
+ */
+#define rcu_dereference_bh(p) \
+               rcu_dereference_check(p, rcu_read_lock_bh_held())
+
+/**
+ * rcu_dereference_sched - fetch RCU-protected pointer, checking for RCU-sched
+ *
+ * Makes rcu_dereference_check() do the dirty work.
+ */
+#define rcu_dereference_sched(p) \
+               rcu_dereference_check(p, rcu_read_lock_sched_held())
+
 /**
  * rcu_assign_pointer - assign (publicize) a pointer to a newly
  * initialized structure that will be dereferenced by RCU read-side