[PATCH 1/2] remove handle_group_stop() in favor of do_signal_stop()

[Oleg Nesterov]

Every time we set SIGNAL_GROUP_EXIT or clear SIGNAL_STOP_DEQUEUED we also
reset ->group_stop_count.

This means that the SIGNAL_GROUP_EXIT check in handle_group_stop() is not
needed, and do_signal_stop() should check SIGNAL_STOP_DEQUEUED only when
->group_stop_count == 0. With these changes handle_group_stop() becomes the
subset of do_signal_stop(), we can kill it and use do_signal_stop() instead.

Also, a preparation for the next patch.

Signed-off-by: Oleg Nesterov <[EMAIL PROTECTED]>

--- PT/kernel/signal.c~1_UNIFY_STOP     2007-12-02 14:36:22.000000000 +0300
+++ PT/kernel/signal.c  2007-12-02 16:56:16.000000000 +0300
@@ -1683,9 +1683,6 @@ static int do_signal_stop(int signr)
        struct signal_struct *sig = current->signal;
        int stop_count;
 
-       if (!likely(sig->flags & SIGNAL_STOP_DEQUEUED))
-               return 0;
-
        if (sig->group_stop_count > 0) {
                /*
                 * There is a group stop in progress.  We don't need to
@@ -1693,12 +1690,14 @@ static int do_signal_stop(int signr)
                 */
                stop_count = --sig->group_stop_count;
        } else {
+               struct task_struct *t;
+
+               if (!likely(sig->flags & SIGNAL_STOP_DEQUEUED))
+                       return 0;
                /*
                 * There is no group stop already in progress.
                 * We must initiate one now.
                 */
-               struct task_struct *t;
-
                sig->group_exit_code = signr;
 
                stop_count = 0;
@@ -1726,38 +1725,6 @@ static int do_signal_stop(int signr)
        return 1;
 }
 
-/*
- * Do appropriate magic when group_stop_count > 0.
- * We return nonzero if we stopped, after releasing the siglock.
- * We return zero if we still hold the siglock and should look
- * for another signal without checking group_stop_count again.
- */
-static int handle_group_stop(void)
-{
-       int stop_count;
-
-       if (current->signal->flags & SIGNAL_GROUP_EXIT)
-               /*
-                * Group stop is so another thread can do a core dump,
-                * or else we are racing against a death signal.
-                * Just punt the stop so we can get the next signal.
-                */
-               return 0;
-
-       /*
-        * There is a group stop in progress.  We stop
-        * without any associated signal being in our queue.
-        */
-       stop_count = --current->signal->group_stop_count;
-       if (stop_count == 0)
-               current->signal->flags = SIGNAL_STOP_STOPPED;
-       current->exit_code = current->signal->group_exit_code;
-       __set_current_state(TASK_STOPPED);
-       spin_unlock_irq(&current->sighand->siglock);
-       finish_stop(stop_count);
-       return 1;
-}
-
 int get_signal_to_deliver(siginfo_t *info, struct k_sigaction *return_ka,
                          struct pt_regs *regs, void *cookie)
 {
@@ -1772,7 +1739,7 @@ relock:
                struct k_sigaction *ka;
 
                if (unlikely(current->signal->group_stop_count > 0) &&
-                   handle_group_stop())
+                   do_signal_stop(0))
                        goto relock;
 
                signr = dequeue_signal(current, mask, info);

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