do_wait: simplify retval/tsk_result/notask_error mess

Now that we don't pass &retval down to other helpers we can simplify
the code more.

- kill tsk_result, just use retval

- add the "notask" label right after the main loop, and
  s/got end/goto notask/ after the fastpath pid check.

  This way we don't need to initialize retval before this
  check and the code becomes a bit more clean, if this pid
  has no attached tasks we should just skip the list search.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Cc: Ingo Molnar <mingo@elte.hu>
Acked-by: Roland McGrath <roland@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 8 insertions, 12 deletions

diff --git a/kernel/exit.c b/kernel/exit.c
index 29622e468b7f..9c6881a0a8b4 100644
--- a/kernel/exit.c
+++ b/kernel/exit.c
@@ -1576,27 +1576,22 @@ repeat:
          * might later match our criteria, even if we are not able to reap
          * it yet.
          */
-        retval = wo->notask_error = -ECHILD;
+        wo->notask_error = -ECHILD;
         if ((wo->wo_type < PIDTYPE_MAX) &&
            (!wo->wo_pid || hlist_empty(&wo->wo_pid->tasks[wo->wo_type])))
-                goto end;
+                goto notask;
 
         current->state = TASK_INTERRUPTIBLE;
         read_lock(&tasklist_lock);
         tsk = current;
         do {
-                int tsk_result = do_wait_thread(wo, tsk);
-
-                if (!tsk_result)
-                        tsk_result = ptrace_do_wait(wo, tsk);
+                retval = do_wait_thread(wo, tsk);
+                if (retval)
+                        goto end;
 
-                if (tsk_result) {
-                        /*
-                         * tasklist_lock is unlocked and we have a final result.
-                         */
-                        retval = tsk_result;
+                retval = ptrace_do_wait(wo, tsk);
+                if (retval)
                         goto end;
-                }
 
                 if (wo->wo_flags & __WNOTHREAD)
                         break;
@@ -1605,6 +1600,7 @@ repeat:
         } while (tsk != current);
         read_unlock(&tasklist_lock);
 
+notask:
         retval = wo->notask_error;
         if (!retval && !(wo->wo_flags & WNOHANG)) {
                 retval = -ERESTARTSYS;