[PATCH RFC tip/core/rcu 17/28] rcu: Make srcu_read_lock_held() call common lockdep-enabled function

From: Paul E. McKenney
Date: Wed Nov 02 2011 - 16:31:19 EST


From: Frederic Weisbecker <fweisbec@xxxxxxxxx>

A common debug_lockdep_rcu_enabled() function is used to check whether
RCU lockdep splats should be reported, but srcu_read_lock() does not
use it. This commit therefore brings srcu_read_lock_held() up to date.

Signed-off-by: Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Frederic Weisbecker <fweisbec@xxxxxxxxx>
Signed-off-by: Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx>
---
include/linux/srcu.h | 5 ++++-
1 files changed, 4 insertions(+), 1 deletions(-)

diff --git a/include/linux/srcu.h b/include/linux/srcu.h
index 4e0a3d4..d4b1244 100644
--- a/include/linux/srcu.h
+++ b/include/linux/srcu.h
@@ -84,6 +84,9 @@ long srcu_batches_completed(struct srcu_struct *sp);
* this assumes we are in an SRCU read-side critical section unless it can
* prove otherwise.
*
+ * 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
@@ -102,7 +105,7 @@ static inline int srcu_read_lock_held(struct srcu_struct *sp)
if (rcu_is_cpu_idle())
return 0;

- if (!debug_locks)
+ if (!debug_lockdep_rcu_enabled())
return 1;

return lock_is_held(&sp->dep_map);
--
1.7.3.2

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