From 74c51971c836f74208e2252460267d1d06b7a59c Mon Sep 17 00:00:00 2001
From: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Date: Mon, 22 Feb 2010 17:04:46 -0800
Subject: [PATCH] --- yaml --- r: 182242 b: refs/heads/master c:
 c26d34a5858f96a564c45048bf5f09319d2abad1 h: refs/heads/master v: v3

---
 [refs]                         |  2 +-
 trunk/include/linux/rcupdate.h | 41 ++++++++++++++++++++++++++++------
 trunk/include/linux/srcu.h     |  8 +++++++
 3 files changed, 43 insertions(+), 8 deletions(-)

diff --git a/[refs] b/[refs]
index a26b5816bf85..8937ca388e01 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 632ee200130899252508c478ad0e808222573fbc
+refs/heads/master: c26d34a5858f96a564c45048bf5f09319d2abad1
diff --git a/trunk/include/linux/rcupdate.h b/trunk/include/linux/rcupdate.h
index e3d37efe2703..839d296a7ac0 100644
--- a/trunk/include/linux/rcupdate.h
+++ b/trunk/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
diff --git a/trunk/include/linux/srcu.h b/trunk/include/linux/srcu.h
index adbe1670b366..3084f80909cd 100644
--- a/trunk/include/linux/srcu.h
+++ b/trunk/include/linux/srcu.h
@@ -105,6 +105,14 @@ static inline int srcu_read_lock_held(struct srcu_struct *sp)
 
 #endif /* #else #ifdef CONFIG_DEBUG_LOCK_ALLOC */
 
+/**
+ * srcu_dereference - fetch SRCU-protected pointer with checking
+ *
+ * Makes rcu_dereference_check() do the dirty work.
+ */
+#define srcu_dereference(p, sp) \
+		rcu_dereference_check(p, srcu_read_lock_held(sp))
+
 /**
  * srcu_read_lock - register a new reader for an SRCU-protected structure.
  * @sp: srcu_struct in which to register the new reader.