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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>
This commit is contained in:
Peter Hurley 2013-03-06 07:20:53 -05:00 committed by Greg Kroah-Hartman
parent f3c8279d69
commit ea648a47e8
1 changed files with 50 additions and 31 deletions
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81
drivers/tty/tty_io.c
View File

@ -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