Improve comment on sema_down.

Thanks to Haobo Xu for pointing this out.

diff --git a/src/threads/synch.c b/src/threads/synch.c
index c2764bc38d1cdb3b47efb0f0a43f8d694d493947..317c68ad501301538f47a697df7a8eaf02d4e077 100644 (file)
--- a/src/threads/synch.c
+++ b/src/threads/synch.c
@@ -55,8 +55,8 @@ sema_init (struct semaphore *sema, unsigned value)
 
    This function may sleep, so it must not be called within an
    interrupt handler.  This function may be called with
 
    This function may sleep, so it must not be called within an
    interrupt handler.  This function may be called with

-   interrupts disabled, but interrupts will be turned back on if
-   we need to sleep. */
+   interrupts disabled, but if it sleeps then the next scheduled
+   thread will probably turn interrupts back on. */

 void
 sema_down (struct semaphore *sema) 
 {
 void
 sema_down (struct semaphore *sema) 
 {