1 files changed, 35 insertions, 9 deletions

diff --git a/include/linux/percpu-rwsem.h b/include/linux/percpu-rwsem.h
index 5e033fe1ff4e..288f5235649a 100644
--- a/include/linux/percpu-rwsem.h
+++ b/include/linux/percpu-rwsem.h
@@ -8,6 +8,7 @@
 #include <linux/wait.h>
 #include <linux/rcu_sync.h>
 #include <linux/lockdep.h>
+#include <linux/cleanup.h>
 
 struct percpu_rw_semaphore {
 	struct rcu_sync		rss;
@@ -42,9 +43,10 @@ is_static struct percpu_rw_semaphore name = {				\
 #define DEFINE_STATIC_PERCPU_RWSEM(name)	\
 	__DEFINE_PERCPU_RWSEM(name, static)
 
-extern bool __percpu_down_read(struct percpu_rw_semaphore *, bool);
+extern bool __percpu_down_read(struct percpu_rw_semaphore *, bool, bool);
 
-static inline void percpu_down_read(struct percpu_rw_semaphore *sem)
+static inline void percpu_down_read_internal(struct percpu_rw_semaphore *sem,
+					     bool freezable)
 {
 	might_sleep();
 
@@ -60,9 +62,9 @@ static inline void percpu_down_read(struct percpu_rw_semaphore *sem)
 	 * anything we did within this RCU-sched read-size critical section.
 	 */
 	if (likely(rcu_sync_is_idle(&sem->rss)))
-		__this_cpu_inc(*sem->read_count);
+		this_cpu_inc(*sem->read_count);
 	else
-		__percpu_down_read(sem, false); /* Unconditional memory barrier */
+		__percpu_down_read(sem, false, freezable); /* Unconditional memory barrier */
 	/*
 	 * The preempt_enable() prevents the compiler from
 	 * bleeding the critical section out.
@@ -70,6 +72,17 @@ static inline void percpu_down_read(struct percpu_rw_semaphore *sem)
 	preempt_enable();
 }
 
+static inline void percpu_down_read(struct percpu_rw_semaphore *sem)
+{
+	percpu_down_read_internal(sem, false);
+}
+
+static inline void percpu_down_read_freezable(struct percpu_rw_semaphore *sem,
+					      bool freeze)
+{
+	percpu_down_read_internal(sem, freeze);
+}
+
 static inline bool percpu_down_read_trylock(struct percpu_rw_semaphore *sem)
 {
 	bool ret = true;
@@ -79,9 +92,9 @@ static inline bool percpu_down_read_trylock(struct percpu_rw_semaphore *sem)
 	 * Same as in percpu_down_read().
 	 */
 	if (likely(rcu_sync_is_idle(&sem->rss)))
-		__this_cpu_inc(*sem->read_count);
+		this_cpu_inc(*sem->read_count);
 	else
-		ret = __percpu_down_read(sem, true); /* Unconditional memory barrier */
+		ret = __percpu_down_read(sem, true, false); /* Unconditional memory barrier */
 	preempt_enable();
 	/*
 	 * The barrier() from preempt_enable() prevents the compiler from
@@ -103,7 +116,7 @@ static inline void percpu_up_read(struct percpu_rw_semaphore *sem)
 	 * Same as in percpu_down_read().
 	 */
 	if (likely(rcu_sync_is_idle(&sem->rss))) {
-		__this_cpu_dec(*sem->read_count);
+		this_cpu_dec(*sem->read_count);
 	} else {
 		/*
 		 * slowpath; reader will only ever wake a single blocked
@@ -115,15 +128,28 @@ static inline void percpu_up_read(struct percpu_rw_semaphore *sem)
 		 * aggregate zero, as that is the only time it matters) they
 		 * will also see our critical section.
 		 */
-		__this_cpu_dec(*sem->read_count);
+		this_cpu_dec(*sem->read_count);
 		rcuwait_wake_up(&sem->writer);
 	}
 	preempt_enable();
 }
 
+extern bool percpu_is_read_locked(struct percpu_rw_semaphore *);
 extern void percpu_down_write(struct percpu_rw_semaphore *);
 extern void percpu_up_write(struct percpu_rw_semaphore *);
 
+DEFINE_GUARD(percpu_read, struct percpu_rw_semaphore *,
+	     percpu_down_read(_T), percpu_up_read(_T))
+DEFINE_GUARD_COND(percpu_read, _try, percpu_down_read_trylock(_T))
+
+DEFINE_GUARD(percpu_write, struct percpu_rw_semaphore *,
+	     percpu_down_write(_T), percpu_up_write(_T))
+
+static inline bool percpu_is_write_locked(struct percpu_rw_semaphore *sem)
+{
+	return atomic_read(&sem->block);
+}
+
 extern int __percpu_init_rwsem(struct percpu_rw_semaphore *,
 				const char *, struct lock_class_key *);
 
@@ -139,7 +165,7 @@ extern void percpu_free_rwsem(struct percpu_rw_semaphore *);
 #define percpu_rwsem_assert_held(sem)	lockdep_assert_held(sem)
 
 static inline void percpu_rwsem_release(struct percpu_rw_semaphore *sem,
-					bool read, unsigned long ip)
+					unsigned long ip)
 {
 	lock_release(&sem->dep_map, ip);
 }