add rwlock implementation

1 files changed, 40 insertions, 0 deletions

diff --git a/src/threads/synch.c b/src/threads/synch.c
index 317c68a..e714ce0 100644
--- a/src/threads/synch.c
+++ b/src/threads/synch.c
@@ -336,3 +336,43 @@ cond_broadcast (struct condition *cond, struct lock *lock)
   while (!list_empty (&cond->waiters))
     cond_signal (cond, lock);
 }
+
+void
+rwlock_init (struct rwlock *rwlock)
+{
+  sema_init (&rwlock->resource, 1);
+  lock_init (&rwlock->rmutex);
+  rwlock->readcount = 0;
+}
+
+void
+rwlock_write_p (struct rwlock *rwlock)
+{
+  sema_down (&rwlock->resource);
+}
+
+void
+rwlock_write_v (struct rwlock *rwlock)
+{
+  sema_up (&rwlock->resource);
+}
+
+void
+rwlock_read_p (struct rwlock *rwlock)
+{
+  lock_acquire (&rwlock->rmutex);
+  rwlock->readcount ++;
+  if (rwlock->readcount == 1)
+    sema_down (&rwlock->resource);
+  lock_release (&rwlock->rmutex);
+}
+
+void
+rwlock_read_v (struct rwlock *rwlock)
+{
+  lock_acquire (&rwlock->rmutex);
+  rwlock->readcount --;
+  if (rwlock->readcount == 0)
+    sema_up (&rwlock->resource);
+  lock_release (&rwlock->rmutex);
+}