Commit 17c1456e authored by Zheng Zengkai's avatar Zheng Zengkai
Browse files

Revert "locking/rwsem: Pass the current atomic count to rwsem_down_read_slowpath()" 

hulk inclusion
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I7F5L7


CVE: NA

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

Revert this patch due to fio performance degradation.
This reverts commit fa59b0b0.

Signed-off-by: default avatarZheng Zengkai <zhengzengkai@huawei.com>
parent d2f1b785

kernel/locking/rwsem.c

+12 −18
Original line number Diff line number Diff line
@@ -270,14 +270,14 @@ static inline void rwsem_set_nonspinnable(struct rw_semaphore *sem) 
					  owner | RWSEM_NONSPINNABLE));

}



static inline bool rwsem_read_trylock(struct rw_semaphore *sem, long *cntp)

static inline bool rwsem_read_trylock(struct rw_semaphore *sem)

{

	*cntp = atomic_long_add_return_acquire(RWSEM_READER_BIAS, &sem->count);

	long cnt = atomic_long_add_return_acquire(RWSEM_READER_BIAS, &sem->count);



	if (WARN_ON_ONCE(*cntp < 0))

	if (WARN_ON_ONCE(cnt < 0))

		rwsem_set_nonspinnable(sem);



	if (!(*cntp & RWSEM_READ_FAILED_MASK)) {

	if (!(cnt & RWSEM_READ_FAILED_MASK)) {

		rwsem_set_reader_owned(sem);

		return true;

	}
@@ -996,9 +996,9 @@ rwsem_spin_on_owner(struct rw_semaphore *sem, unsigned long nonspinnable) 
 * Wait for the read lock to be granted

 */

static struct rw_semaphore __sched *

rwsem_down_read_slowpath(struct rw_semaphore *sem, long count, int state)

rwsem_down_read_slowpath(struct rw_semaphore *sem, int state)

{

	long adjustment = -RWSEM_READER_BIAS;

	long count, adjustment = -RWSEM_READER_BIAS;

	struct rwsem_waiter waiter;

	DEFINE_WAKE_Q(wake_q);

	bool wake = false;
@@ -1344,20 +1344,16 @@ static struct rw_semaphore *rwsem_downgrade_wake(struct rw_semaphore *sem) 
 */

static inline void __down_read(struct rw_semaphore *sem)

{

	long count;



	if (!rwsem_read_trylock(sem, &count)) {

		rwsem_down_read_slowpath(sem, count, TASK_UNINTERRUPTIBLE);

	if (!rwsem_read_trylock(sem)) {

		rwsem_down_read_slowpath(sem, TASK_UNINTERRUPTIBLE);

		DEBUG_RWSEMS_WARN_ON(!is_rwsem_reader_owned(sem), sem);

	}

}



static inline int __down_read_interruptible(struct rw_semaphore *sem)

{

	long count;



	if (!rwsem_read_trylock(sem, &count)) {

		if (IS_ERR(rwsem_down_read_slowpath(sem, count, TASK_INTERRUPTIBLE)))

	if (!rwsem_read_trylock(sem)) {

		if (IS_ERR(rwsem_down_read_slowpath(sem, TASK_INTERRUPTIBLE)))

			return -EINTR;

		DEBUG_RWSEMS_WARN_ON(!is_rwsem_reader_owned(sem), sem);

	}
@@ -1366,10 +1362,8 @@ static inline int __down_read_interruptible(struct rw_semaphore *sem) 


static inline int __down_read_killable(struct rw_semaphore *sem)

{

	long count;



	if (!rwsem_read_trylock(sem, &count)) {

		if (IS_ERR(rwsem_down_read_slowpath(sem, count, TASK_KILLABLE)))

	if (!rwsem_read_trylock(sem)) {

		if (IS_ERR(rwsem_down_read_slowpath(sem, TASK_KILLABLE)))

			return -EINTR;

		DEBUG_RWSEMS_WARN_ON(!is_rwsem_reader_owned(sem), sem);

	}