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-rw-r--r--include/linux/rcupdate.h59
1 files changed, 31 insertions, 28 deletions
diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h
index 581abf848..a0189ba67 100644
--- a/include/linux/rcupdate.h
+++ b/include/linux/rcupdate.h
@@ -160,7 +160,7 @@ void do_trace_rcu_torture_read(const char *rcutorturename,
* more than one CPU).
*/
void call_rcu(struct rcu_head *head,
- void (*func)(struct rcu_head *head));
+ rcu_callback_t func);
#else /* #ifdef CONFIG_PREEMPT_RCU */
@@ -191,7 +191,7 @@ void call_rcu(struct rcu_head *head,
* memory ordering guarantees.
*/
void call_rcu_bh(struct rcu_head *head,
- void (*func)(struct rcu_head *head));
+ rcu_callback_t func);
/**
* call_rcu_sched() - Queue an RCU for invocation after sched grace period.
@@ -213,7 +213,7 @@ void call_rcu_bh(struct rcu_head *head,
* memory ordering guarantees.
*/
void call_rcu_sched(struct rcu_head *head,
- void (*func)(struct rcu_head *rcu));
+ rcu_callback_t func);
void synchronize_sched(void);
@@ -274,7 +274,7 @@ do { \
* See the description of call_rcu() for more detailed information on
* memory ordering guarantees.
*/
-void call_rcu_tasks(struct rcu_head *head, void (*func)(struct rcu_head *head));
+void call_rcu_tasks(struct rcu_head *head, rcu_callback_t func);
void synchronize_rcu_tasks(void);
void rcu_barrier_tasks(void);
@@ -297,12 +297,14 @@ void synchronize_rcu(void);
static inline void __rcu_read_lock(void)
{
- preempt_disable();
+ if (IS_ENABLED(CONFIG_PREEMPT_COUNT))
+ preempt_disable();
}
static inline void __rcu_read_unlock(void)
{
- preempt_enable();
+ if (IS_ENABLED(CONFIG_PREEMPT_COUNT))
+ preempt_enable();
}
static inline void synchronize_rcu(void)
@@ -535,29 +537,9 @@ static inline int rcu_read_lock_sched_held(void)
#endif /* #else #ifdef CONFIG_DEBUG_LOCK_ALLOC */
-/* Deprecate rcu_lockdep_assert(): Use RCU_LOCKDEP_WARN() instead. */
-static inline void __attribute((deprecated)) deprecate_rcu_lockdep_assert(void)
-{
-}
-
#ifdef CONFIG_PROVE_RCU
/**
- * rcu_lockdep_assert - emit lockdep splat if specified condition not met
- * @c: condition to check
- * @s: informative message
- */
-#define rcu_lockdep_assert(c, s) \
- do { \
- static bool __section(.data.unlikely) __warned; \
- deprecate_rcu_lockdep_assert(); \
- if (debug_lockdep_rcu_enabled() && !__warned && !(c)) { \
- __warned = true; \
- lockdep_rcu_suspicious(__FILE__, __LINE__, s); \
- } \
- } while (0)
-
-/**
* RCU_LOCKDEP_WARN - emit lockdep splat if specified condition is met
* @c: condition to check
* @s: informative message
@@ -594,7 +576,6 @@ static inline void rcu_preempt_sleep_check(void)
#else /* #ifdef CONFIG_PROVE_RCU */
-#define rcu_lockdep_assert(c, s) deprecate_rcu_lockdep_assert()
#define RCU_LOCKDEP_WARN(c, s) do { } while (0)
#define rcu_sleep_check() do { } while (0)
@@ -811,6 +792,28 @@ static inline void rcu_preempt_sleep_check(void)
#define rcu_dereference_sched(p) rcu_dereference_sched_check(p, 0)
/**
+ * rcu_pointer_handoff() - Hand off a pointer from RCU to other mechanism
+ * @p: The pointer to hand off
+ *
+ * This is simply an identity function, but it documents where a pointer
+ * is handed off from RCU to some other synchronization mechanism, for
+ * example, reference counting or locking. In C11, it would map to
+ * kill_dependency(). It could be used as follows:
+ *
+ * rcu_read_lock();
+ * p = rcu_dereference(gp);
+ * long_lived = is_long_lived(p);
+ * if (long_lived) {
+ * if (!atomic_inc_not_zero(p->refcnt))
+ * long_lived = false;
+ * else
+ * p = rcu_pointer_handoff(p);
+ * }
+ * rcu_read_unlock();
+ */
+#define rcu_pointer_handoff(p) (p)
+
+/**
* rcu_read_lock() - mark the beginning of an RCU read-side critical section
*
* When synchronize_rcu() is invoked on one CPU while other CPUs
@@ -1065,7 +1068,7 @@ static inline notrace void rcu_read_unlock_sched_notrace(void)
#define __kfree_rcu(head, offset) \
do { \
BUILD_BUG_ON(!__is_kfree_rcu_offset(offset)); \
- kfree_call_rcu(head, (void (*)(struct rcu_head *))(unsigned long)(offset)); \
+ kfree_call_rcu(head, (rcu_callback_t)(unsigned long)(offset)); \
} while (0)
/**