1 files changed, 65 insertions, 6 deletions

diff --git a/kernel/sched/wait_bit.c b/kernel/sched/wait_bit.c
index 84cb3acd9260..ed84ab245a05 100644
--- a/kernel/sched/wait_bit.c
+++ b/kernel/sched/wait_bit.c
@@ -1,10 +1,7 @@
 /*
  * The implementation of the wait_bit*() and related waiting APIs:
  */
-#include <linux/wait_bit.h>
-#include <linux/sched/signal.h>
-#include <linux/sched/debug.h>
-#include <linux/hash.h>
+#include "sched.h"
 
 #define WAIT_TABLE_BITS 8
 #define WAIT_TABLE_SIZE (1 << WAIT_TABLE_BITS)
@@ -29,8 +26,8 @@ int wake_bit_function(struct wait_queue_entry *wq_entry, unsigned mode, int sync
 			wait_bit->key.bit_nr != key->bit_nr ||
 			test_bit(key->bit_nr, key->flags))
 		return 0;
-	else
-		return autoremove_wake_function(wq_entry, mode, sync, key);
+
+	return autoremove_wake_function(wq_entry, mode, sync, key);
 }
 EXPORT_SYMBOL(wake_bit_function);
 
@@ -50,7 +47,9 @@ __wait_on_bit(struct wait_queue_head *wq_head, struct wait_bit_queue_entry *wbq_
 		if (test_bit(wbq_entry->key.bit_nr, wbq_entry->key.flags))
 			ret = (*action)(&wbq_entry->key, mode);
 	} while (test_bit(wbq_entry->key.bit_nr, wbq_entry->key.flags) && !ret);
+
 	finish_wait(wq_head, &wbq_entry->wq_entry);
+
 	return ret;
 }
 EXPORT_SYMBOL(__wait_on_bit);
@@ -73,6 +72,7 @@ int __sched out_of_line_wait_on_bit_timeout(
 	DEFINE_WAIT_BIT(wq_entry, word, bit);
 
 	wq_entry.key.timeout = jiffies + timeout;
+
 	return __wait_on_bit(wq_head, &wq_entry, action, mode);
 }
 EXPORT_SYMBOL_GPL(out_of_line_wait_on_bit_timeout);
@@ -120,6 +120,7 @@ EXPORT_SYMBOL(out_of_line_wait_on_bit_lock);
 void __wake_up_bit(struct wait_queue_head *wq_head, void *word, int bit)
 {
 	struct wait_bit_key key = __WAIT_BIT_KEY_INITIALIZER(word, bit);
+
 	if (waitqueue_active(wq_head))
 		__wake_up(wq_head, TASK_NORMAL, 1, &key);
 }
@@ -148,6 +149,54 @@ void wake_up_bit(void *word, int bit)
 }
 EXPORT_SYMBOL(wake_up_bit);
 
+wait_queue_head_t *__var_waitqueue(void *p)
+{
+	if (BITS_PER_LONG == 64) {
+		unsigned long q = (unsigned long)p;
+
+		return bit_waitqueue((void *)(q & ~1), q & 1);
+	}
+	return bit_waitqueue(p, 0);
+}
+EXPORT_SYMBOL(__var_waitqueue);
+
+static int
+var_wake_function(struct wait_queue_entry *wq_entry, unsigned int mode,
+		  int sync, void *arg)
+{
+	struct wait_bit_key *key = arg;
+	struct wait_bit_queue_entry *wbq_entry =
+		container_of(wq_entry, struct wait_bit_queue_entry, wq_entry);
+
+	if (wbq_entry->key.flags != key->flags ||
+	    wbq_entry->key.bit_nr != key->bit_nr)
+		return 0;
+
+	return autoremove_wake_function(wq_entry, mode, sync, key);
+}
+
+void init_wait_var_entry(struct wait_bit_queue_entry *wbq_entry, void *var, int flags)
+{
+	*wbq_entry = (struct wait_bit_queue_entry){
+		.key = {
+			.flags	= (var),
+			.bit_nr = -1,
+		},
+		.wq_entry = {
+			.private = current,
+			.func	 = var_wake_function,
+			.entry	 = LIST_HEAD_INIT(wbq_entry->wq_entry.entry),
+		},
+	};
+}
+EXPORT_SYMBOL(init_wait_var_entry);
+
+void wake_up_var(void *var)
+{
+	__wake_up_bit(__var_waitqueue(var), var, -1);
+}
+EXPORT_SYMBOL(wake_up_var);
+
 /*
  * Manipulate the atomic_t address to produce a better bit waitqueue table hash
  * index (we're keying off bit -1, but that would produce a horrible hash
@@ -157,6 +206,7 @@ static inline wait_queue_head_t *atomic_t_waitqueue(atomic_t *p)
 {
 	if (BITS_PER_LONG == 64) {
 		unsigned long q = (unsigned long)p;
+
 		return bit_waitqueue((void *)(q & ~1), q & 1);
 	}
 	return bit_waitqueue(p, 0);
@@ -173,6 +223,7 @@ static int wake_atomic_t_function(struct wait_queue_entry *wq_entry, unsigned mo
 	    wait_bit->key.bit_nr != key->bit_nr ||
 	    atomic_read(val) != 0)
 		return 0;
+
 	return autoremove_wake_function(wq_entry, mode, sync, key);
 }
 
@@ -196,6 +247,7 @@ int __wait_on_atomic_t(struct wait_queue_head *wq_head, struct wait_bit_queue_en
 		ret = (*action)(val, mode);
 	} while (!ret && atomic_read(val) != 0);
 	finish_wait(wq_head, &wbq_entry->wq_entry);
+
 	return ret;
 }
 
@@ -226,6 +278,7 @@ __sched int atomic_t_wait(atomic_t *counter, unsigned int mode)
 	schedule();
 	if (signal_pending_state(mode, current))
 		return -EINTR;
+
 	return 0;
 }
 EXPORT_SYMBOL(atomic_t_wait);
@@ -250,6 +303,7 @@ __sched int bit_wait(struct wait_bit_key *word, int mode)
 	schedule();
 	if (signal_pending_state(mode, current))
 		return -EINTR;
+
 	return 0;
 }
 EXPORT_SYMBOL(bit_wait);
@@ -259,6 +313,7 @@ __sched int bit_wait_io(struct wait_bit_key *word, int mode)
 	io_schedule();
 	if (signal_pending_state(mode, current))
 		return -EINTR;
+
 	return 0;
 }
 EXPORT_SYMBOL(bit_wait_io);
@@ -266,11 +321,13 @@ EXPORT_SYMBOL(bit_wait_io);
 __sched int bit_wait_timeout(struct wait_bit_key *word, int mode)
 {
 	unsigned long now = READ_ONCE(jiffies);
+
 	if (time_after_eq(now, word->timeout))
 		return -EAGAIN;
 	schedule_timeout(word->timeout - now);
 	if (signal_pending_state(mode, current))
 		return -EINTR;
+
 	return 0;
 }
 EXPORT_SYMBOL_GPL(bit_wait_timeout);
@@ -278,11 +335,13 @@ EXPORT_SYMBOL_GPL(bit_wait_timeout);
 __sched int bit_wait_io_timeout(struct wait_bit_key *word, int mode)
 {
 	unsigned long now = READ_ONCE(jiffies);
+
 	if (time_after_eq(now, word->timeout))
 		return -EAGAIN;
 	io_schedule_timeout(word->timeout - now);
 	if (signal_pending_state(mode, current))
 		return -EINTR;
+
 	return 0;
 }
 EXPORT_SYMBOL_GPL(bit_wait_io_timeout);