lab3.1: locks

kern/thread/synch.c

@@ -156,6 +156,24 @@ lock_create(const char *name)
 
         // add stuff here as needed
 
+#if OPT_SEMLOCK
+        lock->sem = sem_create(name, 1);
+        if (lock->sem == NULL) {
+		kfree(lock->lk_name);
+		kfree(lock);
+                return NULL;
+        }
+#elif OPT_WCHANLOCK
+	lock->wchan = wchan_create(lock->lk_name);
+	if (lock->wchan == NULL) {
+		kfree(lock->lk_name);
+		kfree(lock);
+		return NULL;
+	}
+        spinlock_init(&lock->slk);
+#endif
+
+        lock->owner = NULL;
         return lock;
 }
 
@@ -167,6 +185,12 @@ lock_destroy(struct lock *lock)
         // add stuff here as needed
 
         kfree(lock->lk_name);
+#if OPT_SEMLOCK
+        sem_destroy(lock->sem);
+#elif OPT_WCHANLOCK
+        wchan_destroy(lock->wchan);
+        spinlock_cleanup(&lock->slk);
+#endif
         kfree(lock);
 }
 
@@ -175,7 +199,19 @@ lock_acquire(struct lock *lock)
 {
         // Write this
 
-        (void)lock;  // suppress warning until code gets written
+#if OPT_SEMLOCK
+        P(lock->sem);
+        lock->owner = curthread;
+#elif OPT_WCHANLOCK
+        spinlock_acquire(&lock->slk);
+        while (lock->owner != NULL) {
+		wchan_sleep(lock->wchan, &lock->slk);
+        }
+        lock->owner = curthread;
+        spinlock_release(&lock->slk);
+#else
+        lock->owner = curthread;
+#endif
 }
 
 void
@@ -183,17 +219,36 @@ lock_release(struct lock *lock)
 {
         // Write this
 
-        (void)lock;  // suppress warning until code gets written
+        KASSERT(lock != NULL);
+        KASSERT(lock_do_i_hold(lock));
+#if OPT_SEMLOCK
+        lock->owner = NULL;
+        V(lock->sem);
+#elif OPT_WCHANLOCK
+        spinlock_acquire(&lock->slk);
+        lock->owner = NULL;
+	wchan_wakeall(lock->wchan, &lock->slk);
+        spinlock_release(&lock->slk);
+#else
+        lock->owner = NULL;
+#endif
 }
 
 bool
 lock_do_i_hold(struct lock *lock)
 {
         // Write this
+        KASSERT(lock != NULL);
+#if OPT_WCHANLOCK
+        bool ret = true;
+        spinlock_acquire(&lock->slk);
+        ret = lock->owner == curthread;
+        spinlock_release(&lock->slk);
+        return ret; // dummy until code gets written
+#else
+        return lock->owner == curthread;
+#endif
 
-        (void)lock;  // suppress warning until code gets written
-
-        return true; // dummy until code gets written
 }
 
 ////////////////////////////////////////////////////////////