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Subject[PATCH RFC tip/core/rcu 17/18] rcu: Provide different lockdep classes for each flavor of RCU
Date
From: Paul E. McKenney <paulmck@linux.vnet.ibm.com>

Proposed for 2.6.34, not for inclusion.

In the past, all three flavors of RCU shared a common lockdep class.
This patch gives each of rcu_read_lock(), rcu_read_lock_bh(), and
rcu_read_lock_sched() their own lockdep classes to permit more precise
checking for read-holding the proper flavor of RCU.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
---
include/linux/rcupdate.h | 39 +++++++++++++++++++++++++++++----------
kernel/rcupdate.c | 10 ++++++++++
2 files changed, 39 insertions(+), 10 deletions(-)
diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h
index 24440f4..723c564 100644
--- a/include/linux/rcupdate.h
+++ b/include/linux/rcupdate.h
@@ -78,14 +78,33 @@ extern void rcu_init(void);
} while (0)

#ifdef CONFIG_DEBUG_LOCK_ALLOC
+
extern struct lockdep_map rcu_lock_map;
-# define rcu_read_acquire() \
- lock_acquire(&rcu_lock_map, 0, 0, 2, 1, NULL, _THIS_IP_)
+# define rcu_read_acquire() \
+ lock_acquire(&rcu_lock_map, 0, 0, 2, 1, NULL, _THIS_IP_)
# define rcu_read_release() lock_release(&rcu_lock_map, 1, _THIS_IP_)
-#else
-# define rcu_read_acquire() do { } while (0)
-# define rcu_read_release() do { } while (0)
-#endif
+
+extern struct lockdep_map rcu_bh_lock_map;
+# define rcu_read_acquire_bh() \
+ lock_acquire(&rcu_bh_lock_map, 0, 0, 2, 1, NULL, _THIS_IP_)
+# define rcu_read_release_bh() lock_release(&rcu_bh_lock_map, 1, _THIS_IP_)
+
+extern struct lockdep_map rcu_sched_lock_map;
+# define rcu_read_acquire_sched() \
+ lock_acquire(&rcu_sched_lock_map, 0, 0, 2, 1, NULL, _THIS_IP_)
+# define rcu_read_release_sched() \
+ lock_release(&rcu_sched_lock_map, 1, _THIS_IP_)
+
+#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)
+
+#endif /* #else #ifdef CONFIG_DEBUG_LOCK_ALLOC */

/**
* rcu_read_lock - mark the beginning of an RCU read-side critical section.
@@ -160,7 +179,7 @@ static inline void rcu_read_lock_bh(void)
{
__rcu_read_lock_bh();
__acquire(RCU_BH);
- rcu_read_acquire();
+ rcu_read_acquire_bh();
}

/*
@@ -170,7 +189,7 @@ static inline void rcu_read_lock_bh(void)
*/
static inline void rcu_read_unlock_bh(void)
{
- rcu_read_release();
+ rcu_read_release_bh();
__release(RCU_BH);
__rcu_read_unlock_bh();
}
@@ -188,7 +207,7 @@ static inline void rcu_read_lock_sched(void)
{
preempt_disable();
__acquire(RCU_SCHED);
- rcu_read_acquire();
+ rcu_read_acquire_sched();
}

/* Used by lockdep and tracing: cannot be traced, cannot call lockdep. */
@@ -205,7 +224,7 @@ static inline notrace void rcu_read_lock_sched_notrace(void)
*/
static inline void rcu_read_unlock_sched(void)
{
- rcu_read_release();
+ rcu_read_release_sched();
__release(RCU_SCHED);
preempt_enable();
}
diff --git a/kernel/rcupdate.c b/kernel/rcupdate.c
index 9b7fd47..033cb55 100644
--- a/kernel/rcupdate.c
+++ b/kernel/rcupdate.c
@@ -50,6 +50,16 @@ static struct lock_class_key rcu_lock_key;
struct lockdep_map rcu_lock_map =
STATIC_LOCKDEP_MAP_INIT("rcu_read_lock", &rcu_lock_key);
EXPORT_SYMBOL_GPL(rcu_lock_map);
+
+static struct lock_class_key rcu_bh_lock_key;
+struct lockdep_map rcu_bh_lock_map =
+ STATIC_LOCKDEP_MAP_INIT("rcu_read_lock_bh", &rcu_bh_lock_key);
+EXPORT_SYMBOL_GPL(rcu_bh_lock_map);
+
+static struct lock_class_key rcu_sched_lock_key;
+struct lockdep_map rcu_sched_lock_map =
+ STATIC_LOCKDEP_MAP_INIT("rcu_read_lock_sched", &rcu_sched_lock_key);
+EXPORT_SYMBOL_GPL(rcu_sched_lock_map);
#endif

/*
--
1.5.2.5


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