coredump_wait: don't call complete_vfork_done()

Now that CLONE_VFORK is killable, coredump_wait() no longer needs
complete_vfork_done().  zap_threads() should find and kill all tasks with
the same ->mm, this includes our parent if ->vfork_done is set.

mm_release() becomes the only caller, unexport complete_vfork_done().

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 2 insertions, 12 deletions

diff --git a/fs/exec.c b/fs/exec.c
index dccdcec913e9..153dee14fe55 100644
--- a/fs/exec.c
+++ b/fs/exec.c
@@ -1926,19 +1926,9 @@ static int coredump_wait(int exit_code, struct core_state *core_state)
                 core_waiters = zap_threads(tsk, mm, core_state, exit_code);
         up_write(&mm->mmap_sem);
 
-        if (unlikely(core_waiters < 0))
-                goto fail;
-
-        /*
-         * Make sure nobody is waiting for us to release the VM,
-         * otherwise we can deadlock when we wait on each other
-         */
-        if (tsk->vfork_done)
-                complete_vfork_done(tsk);
-
-        if (core_waiters)
+        if (core_waiters > 0)
                 wait_for_completion(&core_state->startup);
-fail:
+
         return core_waiters;
 }