Refactor: Move destroying mmap data into process_exit instead of thread

src/threads/thread.c

@@ -401,10 +401,6 @@ thread_exit (void)
   process_exit ();
 #endif
 
-#ifdef VM
-  mmap_destroy ();
-#endif
-
   /* Remove thread from all threads list, set our status to dying,
      and schedule another process.  That process will destroy us
      when it calls thread_schedule_tail(). */

src/userprog/process.c

@@ -25,6 +25,7 @@
 #include "threads/synch.h"
 #include "devices/timer.h"
 #include "vm/page.h"
+#include "vm/mmap.h"
 #ifdef VM
 #include "vm/frame.h"
 #endif
@@ -363,6 +364,9 @@ process_exit (void)
   struct thread *cur = thread_current ();
   uint32_t *pd;
 
+  /* Unmap all memory mapped files */
+  mmap_destroy ();
+
   /* Clean up all open files */
   hash_destroy (&cur->open_files, fd_cleanup);
   hash_destroy (&cur->pages, page_cleanup);