Merge tag 'tty-3.10-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty

Pull tty/serial driver update from Greg Kroah-Hartman:
 "Here's the big tty/serial driver merge request for 3.10-rc1

  Once again, Jiri has a number of TTY driver fixes and cleanups, and
  Peter Hurley came through with a bunch of ldisc fixes that resolve a
  number of reported issues.  There are some other serial driver
  cleanups as well.

  All of these have been in the linux-next tree for a while"

* tag 'tty-3.10-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/tty: (117 commits)
  tty/serial/sirf: fix MODULE_DEVICE_TABLE
  serial: mxs: drop superfluous {get|put}_device
  serial: mxs: fix buffer overflow
  ARM: PL011: add support for extended FIFO-size of PL011-r1p5
  serial_core.c: add put_device() after device_find_child()
  tty: Fix unsafe bit ops in tty_throttle_safe/unthrottle_safe
  serial: sccnxp: Replace pdata.init/exit with regulator API
  serial: sccnxp: Do not override device name
  TTY: pty, fix compilation warning
  TTY: rocket, fix compilation warning
  TTY: ircomm: fix DTR being raised on hang up
  TTY: synclinkmp: fix DTR being raised on hang up
  TTY: synclink_gt: fix DTR being raised on hang up
  TTY: synclink: fix DTR being raised on hang up
  serial: 8250_dw: Fix the stub for dw8250_probe_acpi()
  serial: 8250_dw: Convert to devm_ioremap()
  serial: 8250_dw: Set port capabilities based on CPR register
  serial: 8250_dw: Let ACPI code extract the DMA client info
  serial: 8250_dw: Support clk framework also with ACPI
  serial: 8250_dw: Enable runtime PM
  ...

1 files changed, 118 insertions, 52 deletions

diff --git a/drivers/tty/tty_io.c b/drivers/tty/tty_io.c
index b045268..97ebc8c 100644
--- a/drivers/tty/tty_io.c
+++ b/drivers/tty/tty_io.c
@@ -533,6 +533,60 @@ void tty_wakeup(struct tty_struct *tty)
 EXPORT_SYMBOL_GPL(tty_wakeup);
 
 /**
+ *	tty_signal_session_leader	- sends SIGHUP to session leader
+ *	@tty		controlling tty
+ *	@exit_session	if non-zero, signal all foreground group processes
+ *
+ *	Send SIGHUP and SIGCONT to the session leader and its process group.
+ *	Optionally, signal all processes in the foreground 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, int exit_session)
+{
+	struct task_struct *p;
+	int refs = 0;
+	struct pid *tty_pgrp = NULL;
+
+	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(&tty->ctrl_lock);
+			tty_pgrp = get_pid(tty->pgrp);
+			if (tty->pgrp)
+				p->signal->tty_old_pgrp = get_pid(tty->pgrp);
+			spin_unlock(&tty->ctrl_lock);
+			spin_unlock_irq(&p->sighand->siglock);
+		} while_each_pid_task(tty->session, PIDTYPE_SID, p);
+	}
+	read_unlock(&tasklist_lock);
+
+	if (tty_pgrp) {
+		if (exit_session)
+			kill_pgrp(tty_pgrp, SIGHUP, exit_session);
+		put_pid(tty_pgrp);
+	}
+
+	return refs;
+}
+
+/**
  *	__tty_hangup		-	actual handler for hangup events
  *	@work: tty device
  *
@@ -554,15 +608,13 @@ EXPORT_SYMBOL_GPL(tty_wakeup);
  *		  tasklist_lock to walk task list for hangup event
  *		    ->siglock to protect ->signal/->sighand
  */
-static void __tty_hangup(struct tty_struct *tty)
+static void __tty_hangup(struct tty_struct *tty, int exit_session)
 {
 	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;
@@ -599,39 +651,18 @@ static void __tty_hangup(struct tty_struct *tty)
 	}
 	spin_unlock(&tty_files_lock);
 
+	refs = tty_signal_session_leader(tty, exit_session);
+	/* Account for the p->signal references we killed */
+	while (refs--)
+		tty_kref_put(tty);
+
 	/*
 	 * it drops BTM and thus races with reopen
 	 * we protect the race by TTY_HUPPING
 	 */
 	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);
-
-	spin_lock_irqsave(&tty->ctrl_lock, flags);
+	spin_lock_irq(&tty->ctrl_lock);
 	clear_bit(TTY_THROTTLED, &tty->flags);
 	clear_bit(TTY_PUSH, &tty->flags);
 	clear_bit(TTY_DO_WRITE_WAKEUP, &tty->flags);
@@ -640,11 +671,7 @@ static void __tty_hangup(struct tty_struct *tty)
 	tty->session = NULL;
 	tty->pgrp = NULL;
 	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);
+	spin_unlock_irq(&tty->ctrl_lock);
 
 	/*
 	 * If one of the devices matches a console pointer, we
@@ -666,7 +693,6 @@ static void __tty_hangup(struct tty_struct *tty)
 	 */
 	set_bit(TTY_HUPPED, &tty->flags);
 	clear_bit(TTY_HUPPING, &tty->flags);
-	tty_ldisc_enable(tty);
 
 	tty_unlock(tty);
 
@@ -679,7 +705,7 @@ static void do_tty_hangup(struct work_struct *work)
 	struct tty_struct *tty =
 		container_of(work, struct tty_struct, hangup_work);
 
-	__tty_hangup(tty);
+	__tty_hangup(tty, 0);
 }
 
 /**
@@ -717,7 +743,7 @@ void tty_vhangup(struct tty_struct *tty)
 
 	printk(KERN_DEBUG "%s vhangup...\n", tty_name(tty, buf));
 #endif
-	__tty_hangup(tty);
+	__tty_hangup(tty, 0);
 }
 
 EXPORT_SYMBOL(tty_vhangup);
@@ -741,6 +767,27 @@ void tty_vhangup_self(void)
 }
 
 /**
+ *	tty_vhangup_session		-	hangup session leader exit
+ *	@tty: tty to hangup
+ *
+ *	The session leader is exiting and hanging up its controlling terminal.
+ *	Every process in the foreground process group is signalled SIGHUP.
+ *
+ *	We do this synchronously so that when the syscall returns the process
+ *	is complete. That guarantee is necessary for security reasons.
+ */
+
+static void tty_vhangup_session(struct tty_struct *tty)
+{
+#ifdef TTY_DEBUG_HANGUP
+	char	buf[64];
+
+	printk(KERN_DEBUG "%s vhangup session...\n", tty_name(tty, buf));
+#endif
+	__tty_hangup(tty, 1);
+}
+
+/**
  *	tty_hung_up_p		-	was tty hung up
  *	@filp: file pointer of tty
  *
@@ -797,18 +844,18 @@ void disassociate_ctty(int on_exit)
 
 	tty = get_current_tty();
 	if (tty) {
-		struct pid *tty_pgrp = get_pid(tty->pgrp);
-		if (on_exit) {
-			if (tty->driver->type != TTY_DRIVER_TYPE_PTY)
-				tty_vhangup(tty);
-		}
-		tty_kref_put(tty);
-		if (tty_pgrp) {
-			kill_pgrp(tty_pgrp, SIGHUP, on_exit);
-			if (!on_exit)
+		if (on_exit && tty->driver->type != TTY_DRIVER_TYPE_PTY) {
+			tty_vhangup_session(tty);
+		} else {
+			struct pid *tty_pgrp = tty_get_pgrp(tty);
+			if (tty_pgrp) {
+				kill_pgrp(tty_pgrp, SIGHUP, on_exit);
 				kill_pgrp(tty_pgrp, SIGCONT, on_exit);
-			put_pid(tty_pgrp);
+				put_pid(tty_pgrp);
+			}
 		}
+		tty_kref_put(tty);
+
 	} else if (on_exit) {
 		struct pid *old_pgrp;
 		spin_lock_irq(&current->sighand->siglock);
@@ -1358,9 +1405,7 @@ static int tty_reopen(struct tty_struct *tty)
 	}
 	tty->count++;
 
-	mutex_lock(&tty->ldisc_mutex);
 	WARN_ON(!test_bit(TTY_LDISC, &tty->flags));
-	mutex_unlock(&tty->ldisc_mutex);
 
 	return 0;
 }
@@ -1477,6 +1522,17 @@ void tty_free_termios(struct tty_struct *tty)
 }
 EXPORT_SYMBOL(tty_free_termios);
 
+/**
+ *	tty_flush_works		-	flush all works of a tty
+ *	@tty: tty device to flush works for
+ *
+ *	Sync flush all works belonging to @tty.
+ */
+static void tty_flush_works(struct tty_struct *tty)
+{
+	flush_work(&tty->SAK_work);
+	flush_work(&tty->hangup_work);
+}
 
 /**
  *	release_one_tty		-	release tty structure memory
@@ -1562,6 +1618,7 @@ static void release_tty(struct tty_struct *tty, int idx)
 	tty_free_termios(tty);
 	tty_driver_remove_tty(tty->driver, tty);
 	tty->port->itty = NULL;
+	cancel_work_sync(&tty->port->buf.work);
 
 	if (tty->link)
 		tty_kref_put(tty->link);
@@ -1791,12 +1848,21 @@ int tty_release(struct inode *inode, struct file *filp)
 		return 0;
 
 #ifdef TTY_DEBUG_HANGUP
-	printk(KERN_DEBUG "%s: freeing tty structure...\n", __func__);
+	printk(KERN_DEBUG "%s: %s: final close\n", __func__, tty_name(tty, buf));
 #endif
 	/*
 	 * Ask the line discipline code to release its structures
 	 */
 	tty_ldisc_release(tty, o_tty);
+
+	/* Wait for pending work before tty destruction commmences */
+	tty_flush_works(tty);
+	if (o_tty)
+		tty_flush_works(o_tty);
+
+#ifdef TTY_DEBUG_HANGUP
+	printk(KERN_DEBUG "%s: %s: freeing structure...\n", __func__, tty_name(tty, buf));
+#endif
 	/*
 	 * The release_tty function takes care of the details of clearing
 	 * the slots and preserving the termios structure. The tty_unlock_pair