[PATCH RFC tip/core/rcu 6/6] rcu: Make srcu_read_lock_held() call common lockdep-enabled function

From: Paul E. McKenney
Date: Fri Jul 08 2011 - 11:44:26 EST


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>
---
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 fcbaee7..54a70b7 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 an extended quiescent state, for example,
* if the CPU is in dyntick-idle mode, then rcu_read_lock_held() returns
* false even if the CPU did an rcu_read_lock(). The reason for this is
@@ -96,7 +99,7 @@ long srcu_batches_completed(struct srcu_struct *sp);
*/
static inline int srcu_read_lock_held(struct srcu_struct *sp)
{
- if (debug_locks)
+ if (!debug_lockdep_rcu_enabled())
return lock_is_held(&sp->dep_map);
if (rcu_check_extended_qs())
return 0;
--
1.7.3.2

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