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-rw-r--r--include/linux/rcupdate.h45
1 files changed, 36 insertions, 9 deletions
diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h
index a005cac5e302..3024050c82a1 100644
--- a/include/linux/rcupdate.h
+++ b/include/linux/rcupdate.h
@@ -101,6 +101,11 @@ extern struct lockdep_map rcu_sched_lock_map;
# define rcu_read_release_sched() \
lock_release(&rcu_sched_lock_map, 1, _THIS_IP_)
+static inline int debug_lockdep_rcu_enabled(void)
+{
+ return likely(rcu_scheduler_active && debug_locks);
+}
+
/**
* rcu_read_lock_held - might we be in RCU read-side critical section?
*
@@ -108,12 +113,14 @@ extern struct lockdep_map rcu_sched_lock_map;
* an RCU read-side critical section. In absence of CONFIG_PROVE_LOCKING,
* this assumes we are in an RCU read-side critical section unless it can
* prove otherwise.
+ *
+ * Check rcu_scheduler_active to prevent false positives during boot.
*/
static inline int rcu_read_lock_held(void)
{
- if (debug_locks)
- return lock_is_held(&rcu_lock_map);
- return 1;
+ if (!debug_lockdep_rcu_enabled())
+ return 1;
+ return lock_is_held(&rcu_lock_map);
}
/**
@@ -123,12 +130,14 @@ static inline int rcu_read_lock_held(void)
* an RCU-bh read-side critical section. In absence of CONFIG_PROVE_LOCKING,
* this assumes we are in an RCU-bh read-side critical section unless it can
* prove otherwise.
+ *
+ * Check rcu_scheduler_active to prevent false positives during boot.
*/
static inline int rcu_read_lock_bh_held(void)
{
- if (debug_locks)
- return lock_is_held(&rcu_bh_lock_map);
- return 1;
+ if (!debug_lockdep_rcu_enabled())
+ return 1;
+ return lock_is_held(&rcu_bh_lock_map);
}
/**
@@ -139,15 +148,26 @@ static inline int rcu_read_lock_bh_held(void)
* this assumes we are in an RCU-sched read-side critical section unless it
* can prove otherwise. Note that disabling of preemption (including
* disabling irqs) counts as an RCU-sched read-side critical section.
+ *
+ * Check rcu_scheduler_active to prevent false positives during boot.
*/
+#ifdef CONFIG_PREEMPT
static inline int rcu_read_lock_sched_held(void)
{
int lockdep_opinion = 0;
+ if (!debug_lockdep_rcu_enabled())
+ return 1;
if (debug_locks)
lockdep_opinion = lock_is_held(&rcu_sched_lock_map);
- return lockdep_opinion || preempt_count() != 0 || !rcu_scheduler_active;
+ return lockdep_opinion || preempt_count() != 0;
+}
+#else /* #ifdef CONFIG_PREEMPT */
+static inline int rcu_read_lock_sched_held(void)
+{
+ return 1;
}
+#endif /* #else #ifdef CONFIG_PREEMPT */
#else /* #ifdef CONFIG_DEBUG_LOCK_ALLOC */
@@ -168,10 +188,17 @@ static inline int rcu_read_lock_bh_held(void)
return 1;
}
+#ifdef CONFIG_PREEMPT
static inline int rcu_read_lock_sched_held(void)
{
- return preempt_count() != 0 || !rcu_scheduler_active;
+ return !rcu_scheduler_active || preempt_count() != 0;
+}
+#else /* #ifdef CONFIG_PREEMPT */
+static inline int rcu_read_lock_sched_held(void)
+{
+ return 1;
}
+#endif /* #else #ifdef CONFIG_PREEMPT */
#endif /* #else #ifdef CONFIG_DEBUG_LOCK_ALLOC */
@@ -188,7 +215,7 @@ static inline int rcu_read_lock_sched_held(void)
*/
#define rcu_dereference_check(p, c) \
({ \
- if (debug_locks && !(c)) \
+ if (debug_lockdep_rcu_enabled() && !(c)) \
lockdep_rcu_dereference(__FILE__, __LINE__); \
rcu_dereference_raw(p); \
})