Merge tag 'dt-for-linus-2' of git://git.kernel.org/pub/scm/linux/kernel/git/arm/arm-soc

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

diff --git a/include/linux/srcu.h b/include/linux/srcu.h
index 6eb691b083581ff88ffd9e7c3da73bc5aa2170fd..04f4121a23ae2b6f5854bf35e7678cd9f93fe991 100644 (file)
--- a/include/linux/srcu.h
+++ b/include/linux/srcu.h
@@ -151,30 +151,14 @@ void srcu_barrier(struct srcu_struct *sp);
  * Checks debug_lockdep_rcu_enabled() to prevent false positives during boot
  * and while lockdep is disabled.
  *
- * Note that if the CPU is in the idle loop from an RCU point of view
- * (ie: that we are in the section between rcu_idle_enter() and
- * rcu_idle_exit()) then srcu_read_lock_held() returns false even if
- * the CPU did an srcu_read_lock().  The reason for this is that RCU
- * ignores CPUs that are in such a section, considering these as in
- * extended quiescent state, so such a CPU is effectively never in an
- * RCU read-side critical section regardless of what RCU primitives it
- * invokes.  This state of affairs is required --- we need to keep an
- * RCU-free window in idle where the CPU may possibly enter into low
- * power mode. This way we can notice an extended quiescent state to
- * other CPUs that started a grace period. Otherwise we would delay any
- * grace period as long as we run in the idle task.
- *
- * Similarly, we avoid claiming an SRCU read lock held if the current
- * CPU is offline.
+ * Note that SRCU is based on its own statemachine and it doesn't
+ * relies on normal RCU, it can be called from the CPU which
+ * is in the idle loop from an RCU point of view or offline.
  */
 static inline int srcu_read_lock_held(struct srcu_struct *sp)
 {
        if (!debug_lockdep_rcu_enabled())
                return 1;
-       if (rcu_is_cpu_idle())
-               return 0;
-       if (!rcu_lockdep_current_cpu_online())
-               return 0;
        return lock_is_held(&sp->dep_map);
 }
 
@@ -236,8 +220,6 @@ static inline int srcu_read_lock(struct srcu_struct *sp) __acquires(sp)
        int retval = __srcu_read_lock(sp);
 
        rcu_lock_acquire(&(sp)->dep_map);
-       rcu_lockdep_assert(!rcu_is_cpu_idle(),
-                          "srcu_read_lock() used illegally while idle");
        return retval;
 }
 
@@ -251,8 +233,6 @@ static inline int srcu_read_lock(struct srcu_struct *sp) __acquires(sp)
 static inline void srcu_read_unlock(struct srcu_struct *sp, int idx)
        __releases(sp)
 {
-       rcu_lockdep_assert(!rcu_is_cpu_idle(),
-                          "srcu_read_unlock() used illegally while idle");
        rcu_lock_release(&(sp)->dep_map);
        __srcu_read_unlock(sp, idx);
 }