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kernel: mutex: remove unnecessary schedule locking

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Removes an unnecessary schedule lock/unlock pair from k_mutex_unlock().

Rationale: Given that only the current thread (which would also be the
mutex owner) will be able to modify the mutex object AND that a
recursive unlock ought never trigger any reschedule (as it does not
touch the pend queue), then performing a schedule lock is not needed
prior to testing for a recursive unlock.

Furthermore, even if it is not a recursive unlock, then a schedule lock
is superfluous as the existing spinlock provides sufficient protection.

Signed-off-by: Peter Mitsis <peter.mitsis@intel.com>
This commit is contained in:
Peter Mitsis 2022-04-08 15:07:56 -04:00 committed by Anas Nashif
parent d42b2e6bed
commit e9b288b713
1 changed files with 0 additions and 4 deletions
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4
kernel/mutex.c
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@ -222,8 +222,6 @@ int z_impl_k_mutex_unlock(struct k_mutex *mutex)
*/ */
__ASSERT_NO_MSG(mutex->lock_count > 0U); __ASSERT_NO_MSG(mutex->lock_count > 0U);
z_sched_lock();
LOG_DBG("mutex %p lock_count: %d", mutex, mutex->lock_count); LOG_DBG("mutex %p lock_count: %d", mutex, mutex->lock_count);
/* /*
@ -266,8 +264,6 @@ int z_impl_k_mutex_unlock(struct k_mutex *mutex)
k_mutex_unlock_return: k_mutex_unlock_return:
SYS_PORT_TRACING_OBJ_FUNC_EXIT(k_mutex, unlock, mutex, 0); SYS_PORT_TRACING_OBJ_FUNC_EXIT(k_mutex, unlock, mutex, 0);
k_sched_unlock();
return 0; return 0;
} }