disable pwm7

hc

2024-05-10 23fa18eaa71266feff7ba8d83022d9e1cc83c65a

 kernel/include/linux/percpu-rwsem.h
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@@ -3,37 +3,60 @@
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 #define _LINUX_PERCPU_RWSEM_H
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 #include <linux/atomic.h>
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-#include <linux/rwsem.h>
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 #include <linux/percpu.h>
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 #include <linux/rcuwait.h>
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+#include <linux/wait.h>
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 #include <linux/rcu_sync.h>
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 #include <linux/lockdep.h>
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+
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+void _trace_android_vh_record_pcpu_rwsem_starttime(
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+		struct task_struct *tsk, unsigned long settime);
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 struct percpu_rw_semaphore {
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 	struct rcu_sync		rss;
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 	unsigned int __percpu	*read_count;
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-	struct rw_semaphore	rw_sem; /* slowpath */
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-	struct rcuwait          writer; /* blocked writer */
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-	int			readers_block;
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+	struct rcuwait		writer;
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+	wait_queue_head_t	waiters;
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+	atomic_t		block;
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+#ifdef CONFIG_DEBUG_LOCK_ALLOC
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+	struct lockdep_map	dep_map;
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+#endif
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 };
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-#define DEFINE_STATIC_PERCPU_RWSEM(name)				\
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+struct percpu_rw_semaphore_atomic {
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+	struct percpu_rw_semaphore rw_sem;
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+	struct list_head destroy_list_entry;
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+};
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+
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+#ifdef CONFIG_DEBUG_LOCK_ALLOC
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+#define __PERCPU_RWSEM_DEP_MAP_INIT(lockname)	.dep_map = { .name = #lockname },
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+#else
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+#define __PERCPU_RWSEM_DEP_MAP_INIT(lockname)
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+#endif
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+
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+#define __DEFINE_PERCPU_RWSEM(name, is_static)				\
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 static DEFINE_PER_CPU(unsigned int, __percpu_rwsem_rc_##name);		\
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-static struct percpu_rw_semaphore name = {				\
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-	.rss = __RCU_SYNC_INITIALIZER(name.rss, RCU_SCHED_SYNC),	\
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+is_static struct percpu_rw_semaphore name = {				\
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+	.rss = __RCU_SYNC_INITIALIZER(name.rss),			\
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 	.read_count = &__percpu_rwsem_rc_##name,			\
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-	.rw_sem = __RWSEM_INITIALIZER(name.rw_sem),			\
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 	.writer = __RCUWAIT_INITIALIZER(name.writer),			\
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+	.waiters = __WAIT_QUEUE_HEAD_INITIALIZER(name.waiters),		\
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+	.block = ATOMIC_INIT(0),					\
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+	__PERCPU_RWSEM_DEP_MAP_INIT(name)				\
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 }
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-extern int __percpu_down_read(struct percpu_rw_semaphore *, int);
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-extern void __percpu_up_read(struct percpu_rw_semaphore *);
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+#define DEFINE_PERCPU_RWSEM(name)		\
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+	__DEFINE_PERCPU_RWSEM(name, /* not static */)
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+#define DEFINE_STATIC_PERCPU_RWSEM(name)	\
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+	__DEFINE_PERCPU_RWSEM(name, static)
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52
 
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-static inline void percpu_down_read_preempt_disable(struct percpu_rw_semaphore *sem)
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+extern bool __percpu_down_read(struct percpu_rw_semaphore *, bool);
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+
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+static inline void percpu_down_read(struct percpu_rw_semaphore *sem)
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 {
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 	might_sleep();
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-	rwsem_acquire_read(&sem->rw_sem.dep_map, 0, 0, _RET_IP_);
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+	rwsem_acquire_read(&sem->dep_map, 0, 0, _RET_IP_);
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 	preempt_disable();
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 	/*
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@@ -41,35 +64,32 @@
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 	 * cannot both change sem->state from readers_fast and start checking
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 	 * counters while we are here. So if we see !sem->state, we know that
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 	 * the writer won't be checking until we're past the preempt_enable()
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-	 * and that one the synchronize_sched() is done, the writer will see
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+	 * and that once the synchronize_rcu() is done, the writer will see
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 	 * anything we did within this RCU-sched read-size critical section.
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 	 */
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-	__this_cpu_inc(*sem->read_count);
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-	if (unlikely(!rcu_sync_is_idle(&sem->rss)))
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+	if (likely(rcu_sync_is_idle(&sem->rss)))
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+		this_cpu_inc(*sem->read_count);
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+	else
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 		__percpu_down_read(sem, false); /* Unconditional memory barrier */
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-	barrier();
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 	/*
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-	 * The barrier() prevents the compiler from
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+	 * The preempt_enable() prevents the compiler from
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 	 * bleeding the critical section out.
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 	 */
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-}
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-
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-static inline void percpu_down_read(struct percpu_rw_semaphore *sem)
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-{
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-	percpu_down_read_preempt_disable(sem);
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 	preempt_enable();
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+	_trace_android_vh_record_pcpu_rwsem_starttime(current, jiffies);
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 }
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-static inline int percpu_down_read_trylock(struct percpu_rw_semaphore *sem)
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+static inline bool percpu_down_read_trylock(struct percpu_rw_semaphore *sem)
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 {
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-	int ret = 1;
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+	bool ret = true;
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85
 
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 	preempt_disable();
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 	/*
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 	 * Same as in percpu_down_read().
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 	 */
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-	__this_cpu_inc(*sem->read_count);
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-	if (unlikely(!rcu_sync_is_idle(&sem->rss)))
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+	if (likely(rcu_sync_is_idle(&sem->rss)))
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+		this_cpu_inc(*sem->read_count);
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+	else
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 		ret = __percpu_down_read(sem, true); /* Unconditional memory barrier */
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 	preempt_enable();
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 	/*
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@@ -77,35 +97,40 @@
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 	 * bleeding the critical section out.
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 	 */
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-	if (ret)
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-		rwsem_acquire_read(&sem->rw_sem.dep_map, 0, 1, _RET_IP_);
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+	if (ret) {
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+		_trace_android_vh_record_pcpu_rwsem_starttime(current, jiffies);
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+		rwsem_acquire_read(&sem->dep_map, 0, 1, _RET_IP_);
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+	}
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 	return ret;
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 }
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-static inline void percpu_up_read_preempt_enable(struct percpu_rw_semaphore *sem)
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+static inline void percpu_up_read(struct percpu_rw_semaphore *sem)
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 {
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-	/*
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-	 * The barrier() prevents the compiler from
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-	 * bleeding the critical section out.
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-	 */
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-	barrier();
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+	rwsem_release(&sem->dep_map, _RET_IP_);
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+
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+	preempt_disable();
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 	/*
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 	 * Same as in percpu_down_read().
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 	 */
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-	if (likely(rcu_sync_is_idle(&sem->rss)))
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-		__this_cpu_dec(*sem->read_count);
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-	else
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-		__percpu_up_read(sem); /* Unconditional memory barrier */
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+	if (likely(rcu_sync_is_idle(&sem->rss))) {
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+		this_cpu_dec(*sem->read_count);
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+	} else {
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+		/*
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+		 * slowpath; reader will only ever wake a single blocked
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+		 * writer.
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+		 */
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+		smp_mb(); /* B matches C */
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+		/*
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+		 * In other words, if they see our decrement (presumably to
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+		 * aggregate zero, as that is the only time it matters) they
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+		 * will also see our critical section.
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+		 */
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+		this_cpu_dec(*sem->read_count);
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+		rcuwait_wake_up(&sem->writer);
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+	}
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+	_trace_android_vh_record_pcpu_rwsem_starttime(current, 0);
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 	preempt_enable();
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-
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-	rwsem_release(&sem->rw_sem.dep_map, 1, _RET_IP_);
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-}
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-
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-static inline void percpu_up_read(struct percpu_rw_semaphore *sem)
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-{
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-	preempt_disable();
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-	percpu_up_read_preempt_enable(sem);
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 }
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 extern void percpu_down_write(struct percpu_rw_semaphore *);
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@@ -114,7 +139,11 @@
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 extern int __percpu_init_rwsem(struct percpu_rw_semaphore *,
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 				const char *, struct lock_class_key *);
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+/* Can't be called in atomic context. */
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 extern void percpu_free_rwsem(struct percpu_rw_semaphore *);
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+
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+/* Invokes percpu_free_rwsem and frees the semaphore from a worker thread. */
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+extern void percpu_rwsem_async_destroy(struct percpu_rw_semaphore_atomic *sem);
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 #define percpu_init_rwsem(sem)					\
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 ({								\
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@@ -122,29 +151,19 @@
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 	__percpu_init_rwsem(sem, #sem, &rwsem_key);		\
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 })
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-#define percpu_rwsem_is_held(sem) lockdep_is_held(&(sem)->rw_sem)
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-
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-#define percpu_rwsem_assert_held(sem)				\
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-	lockdep_assert_held(&(sem)->rw_sem)
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+#define percpu_rwsem_is_held(sem)	lockdep_is_held(sem)
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+#define percpu_rwsem_assert_held(sem)	lockdep_assert_held(sem)
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 static inline void percpu_rwsem_release(struct percpu_rw_semaphore *sem,
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 					bool read, unsigned long ip)
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 {
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-	lock_release(&sem->rw_sem.dep_map, 1, ip);
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-#ifdef CONFIG_RWSEM_SPIN_ON_OWNER
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-	if (!read)
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-		sem->rw_sem.owner = RWSEM_OWNER_UNKNOWN;
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-#endif
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+	lock_release(&sem->dep_map, ip);
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 }
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 static inline void percpu_rwsem_acquire(struct percpu_rw_semaphore *sem,
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 					bool read, unsigned long ip)
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 {
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-	lock_acquire(&sem->rw_sem.dep_map, 0, 1, read, 1, NULL, ip);
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-#ifdef CONFIG_RWSEM_SPIN_ON_OWNER
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-	if (!read)
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-		sem->rw_sem.owner = current;
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-#endif
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+	lock_acquire(&sem->dep_map, 0, 1, read, 1, NULL, ip);
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 }
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 #endif