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lt1 (sem) pass #3

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lt1 (sem) pass #3

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3 changes: 3 additions & 0 deletions kern/include/synch.h
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Original file line number Diff line number Diff line change
Expand Up @@ -76,6 +76,9 @@ struct lock {
char *lk_name;
HANGMAN_LOCKABLE(lk_hangman); /* Deadlock detector hook. */
// add what you need here
struct thread *lk_owner;
volatile bool lk_locked;
struct semaphore *lk_sem;
// (don't forget to mark things volatile as needed)
};

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21 changes: 15 additions & 6 deletions kern/thread/synch.c
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Original file line number Diff line number Diff line change
Expand Up @@ -158,6 +158,9 @@ lock_create(const char *name)

// add stuff here as needed

lock->lk_locked = false;
lock->lk_owner = NULL;
lock->lk_sem = sem_create(name, 1);
return lock;
}

Expand All @@ -167,7 +170,7 @@ lock_destroy(struct lock *lock)
KASSERT(lock != NULL);

// add stuff here as needed

sem_destroy(lock->lk_sem);
kfree(lock->lk_name);
kfree(lock);
}
Expand All @@ -179,8 +182,10 @@ lock_acquire(struct lock *lock)
//HANGMAN_WAIT(&curthread->t_hangman, &lock->lk_hangman);

// Write this
P(lock->lk_sem);

(void)lock; // suppress warning until code gets written
lock->lk_owner = curthread;
lock->lk_locked = true;

/* Call this (atomically) once the lock is acquired */
//HANGMAN_ACQUIRE(&curthread->t_hangman, &lock->lk_hangman);
Expand All @@ -194,17 +199,21 @@ lock_release(struct lock *lock)

// Write this

(void)lock; // suppress warning until code gets written
lock->lk_locked = false;
lock->lk_owner = NULL;
V(lock->lk_sem);
}

bool
lock_do_i_hold(struct lock *lock)
{
// Write this
(void) lock;
if (curthread == NULL) {
return false;
}

(void)lock; // suppress warning until code gets written

return true; // dummy until code gets written
return (lock->lk_owner == curthread);
}

////////////////////////////////////////////////////////////
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