tty: Refactor session leader SIGHUP from __tty_hangup()

Reduce complexity of __tty_hangup(); separate SIGHUP signalling
into tty_signal_session_leader().

Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Acked-by: Jiri Slaby <jslaby@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/tty/tty_io.c b/drivers/tty/tty_io.c
index 05400acbc456f1e9e888972e5c73c5c4f634d71c..706c23b9cb959856b98913283750859afb47f4f5 100644 (file)
--- a/drivers/tty/tty_io.c
+++ b/drivers/tty/tty_io.c
@@ -532,6 +532,51 @@ void tty_wakeup(struct tty_struct *tty)
 
 EXPORT_SYMBOL_GPL(tty_wakeup);
 
+/**
+ *     tty_signal_session_leader       - sends SIGHUP to session leader
+ *
+ *     Send SIGHUP and SIGCONT to the session leader and its
+ *     process group.
+ *
+ *     Returns the number of processes in the session with this tty
+ *     as their controlling terminal. This value is used to drop
+ *     tty references for those processes.
+ */
+static int tty_signal_session_leader(struct tty_struct *tty)
+{
+       struct task_struct *p;
+       unsigned long flags;
+       int refs = 0;
+
+       read_lock(&tasklist_lock);
+       if (tty->session) {
+               do_each_pid_task(tty->session, PIDTYPE_SID, p) {
+                       spin_lock_irq(&p->sighand->siglock);
+                       if (p->signal->tty == tty) {
+                               p->signal->tty = NULL;
+                               /* We defer the dereferences outside fo
+                                  the tasklist lock */
+                               refs++;
+                       }
+                       if (!p->signal->leader) {
+                               spin_unlock_irq(&p->sighand->siglock);
+                               continue;
+                       }
+                       __group_send_sig_info(SIGHUP, SEND_SIG_PRIV, p);
+                       __group_send_sig_info(SIGCONT, SEND_SIG_PRIV, p);
+                       put_pid(p->signal->tty_old_pgrp);  /* A noop */
+                       spin_lock_irqsave(&tty->ctrl_lock, flags);
+                       if (tty->pgrp)
+                               p->signal->tty_old_pgrp = get_pid(tty->pgrp);
+                       spin_unlock_irqrestore(&tty->ctrl_lock, flags);
+                       spin_unlock_irq(&p->sighand->siglock);
+               } while_each_pid_task(tty->session, PIDTYPE_SID, p);
+       }
+       read_unlock(&tasklist_lock);
+
+       return refs;
+}
+
 /**
  *     __tty_hangup            -       actual handler for hangup events
  *     @work: tty device
@@ -558,11 +603,10 @@ static void __tty_hangup(struct tty_struct *tty)
 {
        struct file *cons_filp = NULL;
        struct file *filp, *f = NULL;
-       struct task_struct *p;
        struct tty_file_private *priv;
        int    closecount = 0, n;
        unsigned long flags;
-       int refs = 0;
+       int refs;
 
        if (!tty)
                return;
@@ -605,31 +649,10 @@ static void __tty_hangup(struct tty_struct *tty)
         */
        tty_ldisc_hangup(tty);
 
-       read_lock(&tasklist_lock);
-       if (tty->session) {
-               do_each_pid_task(tty->session, PIDTYPE_SID, p) {
-                       spin_lock_irq(&p->sighand->siglock);
-                       if (p->signal->tty == tty) {
-                               p->signal->tty = NULL;
-                               /* We defer the dereferences outside fo
-                                  the tasklist lock */
-                               refs++;
-                       }
-                       if (!p->signal->leader) {
-                               spin_unlock_irq(&p->sighand->siglock);
-                               continue;
-                       }
-                       __group_send_sig_info(SIGHUP, SEND_SIG_PRIV, p);
-                       __group_send_sig_info(SIGCONT, SEND_SIG_PRIV, p);
-                       put_pid(p->signal->tty_old_pgrp);  /* A noop */
-                       spin_lock_irqsave(&tty->ctrl_lock, flags);
-                       if (tty->pgrp)
-                               p->signal->tty_old_pgrp = get_pid(tty->pgrp);
-                       spin_unlock_irqrestore(&tty->ctrl_lock, flags);
-                       spin_unlock_irq(&p->sighand->siglock);
-               } while_each_pid_task(tty->session, PIDTYPE_SID, p);
-       }
-       read_unlock(&tasklist_lock);
+       refs = tty_signal_session_leader(tty);
+       /* Account for the p->signal references we killed */
+       while (refs--)
+               tty_kref_put(tty);
 
        spin_lock_irqsave(&tty->ctrl_lock, flags);
        clear_bit(TTY_THROTTLED, &tty->flags);
@@ -642,10 +665,6 @@ static void __tty_hangup(struct tty_struct *tty)
        tty->ctrl_status = 0;
        spin_unlock_irqrestore(&tty->ctrl_lock, flags);
 
-       /* Account for the p->signal references we killed */
-       while (refs--)
-               tty_kref_put(tty);
-
        /*
         * If one of the devices matches a console pointer, we
         * cannot just call hangup() because that will cause