Commit e1e05a2a authored by Zizhi Wo's avatar Zizhi Wo Committed by Baokun Li
Browse files

wait_on_bit: Add wait_on_bit_acquire() to provide memory barrier 

hulk inclusion
category: other
bugzilla: https://gitee.com/openeuler/kernel/issues/IB5UKT



--------------------------------

For the previously combined 8238b457 ("wait_on_bit: add an acquire
memory barrier") mainline patch, in order to avoid additional effects,
revert the test_bit_acquire() in the wait_on_bit_xx function to the
original test_bit().

In addition, define wait_on_bit_acquire() to narrow down the scope, which
contains test_bit_acquire() that provide memory barrier.

Signed-off-by: default avatarZizhi Wo <wozizhi@huawei.com>
Signed-off-by: default avatarBaokun Li <libaokun1@huawei.com>
parent d78601ed

include/linux/wait_bit.h

+29 −4
Original line number Diff line number Diff line
@@ -28,7 +28,9 @@ int __wait_on_bit(struct wait_queue_head *wq_head, struct wait_bit_queue_entry * 
int __wait_on_bit_lock(struct wait_queue_head *wq_head, struct wait_bit_queue_entry *wbq_entry, wait_bit_action_f *action, unsigned int mode);

void wake_up_bit(void *word, int bit);

int out_of_line_wait_on_bit(void *word, int, wait_bit_action_f *action, unsigned int mode);

int out_of_line_wait_on_bit_acquire(void *word, int, wait_bit_action_f *action, unsigned int mode);

int out_of_line_wait_on_bit_timeout(void *word, int, wait_bit_action_f *action, unsigned int mode, unsigned long timeout);

int out_of_line_wait_on_bit_timeout_acquire(void *word, int, wait_bit_action_f *action, unsigned int mode, unsigned long timeout);

int out_of_line_wait_on_bit_lock(void *word, int, wait_bit_action_f *action, unsigned int mode);

struct wait_queue_head *bit_waitqueue(void *word, int bit);

extern void __init wait_bit_init(void);
@@ -71,7 +73,7 @@ static inline int 
wait_on_bit(unsigned long *word, int bit, unsigned mode)

{

	might_sleep();

	if (!test_bit_acquire(bit, word))

	if (!test_bit(bit, word))

		return 0;

	return out_of_line_wait_on_bit(word, bit,

				       bit_wait,
@@ -96,7 +98,7 @@ static inline int 
wait_on_bit_io(unsigned long *word, int bit, unsigned mode)

{

	might_sleep();

	if (!test_bit_acquire(bit, word))

	if (!test_bit(bit, word))

		return 0;

	return out_of_line_wait_on_bit(word, bit,

				       bit_wait_io,
@@ -123,7 +125,7 @@ wait_on_bit_timeout(unsigned long *word, int bit, unsigned mode, 
		    unsigned long timeout)

{

	might_sleep();

	if (!test_bit_acquire(bit, word))

	if (!test_bit(bit, word))

		return 0;

	return out_of_line_wait_on_bit_timeout(word, bit,

					       bit_wait_timeout,
@@ -151,7 +153,7 @@ wait_on_bit_action(unsigned long *word, int bit, wait_bit_action_f *action, 
		   unsigned mode)

{

	might_sleep();

	if (!test_bit_acquire(bit, word))

	if (!test_bit(bit, word))

		return 0;

	return out_of_line_wait_on_bit(word, bit, action, mode);

}
@@ -235,6 +237,29 @@ wait_on_bit_lock_action(unsigned long *word, int bit, wait_bit_action_f *action, 
	return out_of_line_wait_on_bit_lock(word, bit, action, mode);

}



static inline int

wait_on_bit_acquire(unsigned long *word, int bit, unsigned mode)

{

	might_sleep();

	if (!test_bit_acquire(bit, word))

		return 0;

	return out_of_line_wait_on_bit_acquire(word, bit,

					       bit_wait,

					       mode);

}



static inline int

wait_on_bit_timeout_acquire(unsigned long *word, int bit, unsigned mode,

			    unsigned long timeout)

{

	might_sleep();

	if (!test_bit_acquire(bit, word))

		return 0;

	return out_of_line_wait_on_bit_timeout_acquire(word, bit,

						       bit_wait_timeout,

						       mode, timeout);

}



extern void init_wait_var_entry(struct wait_bit_queue_entry *wbq_entry, void *var, int flags);

extern void wake_up_var(void *var);

extern wait_queue_head_t *__var_waitqueue(void *p);

kernel/sched/wait_bit.c

+41 −1
Original line number Diff line number Diff line
@@ -47,7 +47,7 @@ __wait_on_bit(struct wait_queue_head *wq_head, struct wait_bit_queue_entry *wbq_ 
		prepare_to_wait(wq_head, &wbq_entry->wq_entry, mode);

		if (test_bit(wbq_entry->key.bit_nr, wbq_entry->key.flags))

			ret = (*action)(&wbq_entry->key, mode);

	} while (test_bit_acquire(wbq_entry->key.bit_nr, wbq_entry->key.flags) && !ret);

	} while (test_bit(wbq_entry->key.bit_nr, wbq_entry->key.flags) && !ret);



	finish_wait(wq_head, &wbq_entry->wq_entry);
@@ -55,6 +55,23 @@ __wait_on_bit(struct wait_queue_head *wq_head, struct wait_bit_queue_entry *wbq_ 
}

EXPORT_SYMBOL(__wait_on_bit);



static int __sched

__wait_on_bit_acquire(struct wait_queue_head *wq_head, struct wait_bit_queue_entry *wbq_entry,

	      wait_bit_action_f *action, unsigned mode)

{

	int ret = 0;



	do {

		prepare_to_wait(wq_head, &wbq_entry->wq_entry, mode);

		if (test_bit(wbq_entry->key.bit_nr, wbq_entry->key.flags))

			ret = (*action)(&wbq_entry->key, mode);

	} while (test_bit_acquire(wbq_entry->key.bit_nr, wbq_entry->key.flags) && !ret);



	finish_wait(wq_head, &wbq_entry->wq_entry);



	return ret;

}



int __sched out_of_line_wait_on_bit(void *word, int bit,

				    wait_bit_action_f *action, unsigned mode)

{
@@ -65,6 +82,29 @@ int __sched out_of_line_wait_on_bit(void *word, int bit, 
}

EXPORT_SYMBOL(out_of_line_wait_on_bit);



int __sched out_of_line_wait_on_bit_acquire(void *word, int bit,

					    wait_bit_action_f *action, unsigned mode)

{

	struct wait_queue_head *wq_head = bit_waitqueue(word, bit);

	DEFINE_WAIT_BIT(wq_entry, word, bit);



	return __wait_on_bit_acquire(wq_head, &wq_entry, action, mode);

}

EXPORT_SYMBOL(out_of_line_wait_on_bit_acquire);



int __sched out_of_line_wait_on_bit_timeout_acquire(

	void *word, int bit, wait_bit_action_f *action,

	unsigned mode, unsigned long timeout)

{

	struct wait_queue_head *wq_head = bit_waitqueue(word, bit);

	DEFINE_WAIT_BIT(wq_entry, word, bit);



	wq_entry.key.timeout = jiffies + timeout;



	return __wait_on_bit_acquire(wq_head, &wq_entry, action, mode);

}

EXPORT_SYMBOL_GPL(out_of_line_wait_on_bit_timeout_acquire);



int __sched out_of_line_wait_on_bit_timeout(

	void *word, int bit, wait_bit_action_f *action,

	unsigned mode, unsigned long timeout)