streamline copyin/copyout code in usertests

fix bugs in read/write return values when there's an error

1 files changed, 1 insertions, 1 deletions

diff --git a/kernel/pipe.c b/kernel/pipe.c
index c066afb..7ed402d 100644
--- a/kernel/pipe.c
+++ b/kernel/pipe.c
@@ -96,7 +96,7 @@ pipewrite(struct pipe *pi, uint64 addr, int n)
   }
   wakeup(&pi->nread);
   release(&pi->lock);
-  return n;
+  return i;
 }
 
 int