Merge branch 'linux-next' of git://git.kernel.org/pub/scm/linux/kernel/git/jbarnes/pci

[~andy/linux] / include / linux / rcupdate.h

diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h
index d201c155f70c27dbeb2c456dd87d76b2288843dc..81c04f4348ecac0afe5b8b073d90f6f14c822599 100644 (file)
--- a/include/linux/rcupdate.h
+++ b/include/linux/rcupdate.h
@@ -250,41 +250,8 @@ static inline void rcu_lock_release(struct lockdep_map *map)
 }
 
 extern struct lockdep_map rcu_lock_map;
-
-static inline void rcu_read_acquire(void)
-{
-       rcu_lock_acquire(&rcu_lock_map);
-}
-
-static inline void rcu_read_release(void)
-{
-       rcu_lock_release(&rcu_lock_map);
-}
-
 extern struct lockdep_map rcu_bh_lock_map;
-
-static inline void rcu_read_acquire_bh(void)
-{
-       rcu_lock_acquire(&rcu_bh_lock_map);
-}
-
-static inline void rcu_read_release_bh(void)
-{
-       rcu_lock_release(&rcu_bh_lock_map);
-}
-
 extern struct lockdep_map rcu_sched_lock_map;
-
-static inline void rcu_read_acquire_sched(void)
-{
-       rcu_lock_acquire(&rcu_sched_lock_map);
-}
-
-static inline void rcu_read_release_sched(void)
-{
-       rcu_lock_release(&rcu_sched_lock_map);
-}
-
 extern int debug_lockdep_rcu_enabled(void);
 
 /**
@@ -298,6 +265,11 @@ extern int debug_lockdep_rcu_enabled(void);
  *
  * Checks debug_lockdep_rcu_enabled() to prevent false positives during boot
  * and while lockdep is disabled.
+ *
+ * Note that rcu_read_lock() and the matching rcu_read_unlock() must
+ * occur in the same context, for example, it is illegal to invoke
+ * rcu_read_unlock() in process context if the matching rcu_read_lock()
+ * was invoked from within an irq handler.
  */
 static inline int rcu_read_lock_held(void)
 {
@@ -364,12 +336,8 @@ static inline int rcu_read_lock_sched_held(void)
 
 #else /* #ifdef CONFIG_DEBUG_LOCK_ALLOC */
 
-# define rcu_read_acquire()            do { } while (0)
-# define rcu_read_release()            do { } while (0)
-# define rcu_read_acquire_bh()         do { } while (0)
-# define rcu_read_release_bh()         do { } while (0)
-# define rcu_read_acquire_sched()      do { } while (0)
-# define rcu_read_release_sched()      do { } while (0)
+# define rcu_lock_acquire(a)           do { } while (0)
+# define rcu_lock_release(a)           do { } while (0)
 
 static inline int rcu_read_lock_held(void)
 {
@@ -690,7 +658,7 @@ static inline void rcu_read_lock(void)
 {
        __rcu_read_lock();
        __acquire(RCU);
-       rcu_read_acquire();
+       rcu_lock_acquire(&rcu_lock_map);
 }
 
 /*
@@ -710,7 +678,7 @@ static inline void rcu_read_lock(void)
  */
 static inline void rcu_read_unlock(void)
 {
-       rcu_read_release();
+       rcu_lock_release(&rcu_lock_map);
        __release(RCU);
        __rcu_read_unlock();
 }
@@ -726,12 +694,17 @@ static inline void rcu_read_unlock(void)
  * critical sections in interrupt context can use just rcu_read_lock(),
  * though this should at least be commented to avoid confusing people
  * reading the code.
+ *
+ * Note that rcu_read_lock_bh() and the matching rcu_read_unlock_bh()
+ * must occur in the same context, for example, it is illegal to invoke
+ * rcu_read_unlock_bh() from one task if the matching rcu_read_lock_bh()
+ * was invoked from some other task.
  */
 static inline void rcu_read_lock_bh(void)
 {
        local_bh_disable();
        __acquire(RCU_BH);
-       rcu_read_acquire_bh();
+       rcu_lock_acquire(&rcu_bh_lock_map);
 }
 
 /*
@@ -741,7 +714,7 @@ static inline void rcu_read_lock_bh(void)
  */
 static inline void rcu_read_unlock_bh(void)
 {
-       rcu_read_release_bh();
+       rcu_lock_release(&rcu_bh_lock_map);
        __release(RCU_BH);
        local_bh_enable();
 }
@@ -753,12 +726,17 @@ static inline void rcu_read_unlock_bh(void)
  * are being done using call_rcu_sched() or synchronize_rcu_sched().
  * Read-side critical sections can also be introduced by anything that
  * disables preemption, including local_irq_disable() and friends.
+ *
+ * Note that rcu_read_lock_sched() and the matching rcu_read_unlock_sched()
+ * must occur in the same context, for example, it is illegal to invoke
+ * rcu_read_unlock_sched() from process context if the matching
+ * rcu_read_lock_sched() was invoked from an NMI handler.
  */
 static inline void rcu_read_lock_sched(void)
 {
        preempt_disable();
        __acquire(RCU_SCHED);
-       rcu_read_acquire_sched();
+       rcu_lock_acquire(&rcu_sched_lock_map);
 }
 
 /* Used by lockdep and tracing: cannot be traced, cannot call lockdep. */
@@ -775,7 +753,7 @@ static inline notrace void rcu_read_lock_sched_notrace(void)
  */
 static inline void rcu_read_unlock_sched(void)
 {
-       rcu_read_release_sched();
+       rcu_lock_release(&rcu_sched_lock_map);
        __release(RCU_SCHED);
        preempt_enable();
 }