commit d41861ca19c9e96f12a4f1ebbc8255d00909a232
author Peter Hurley <peter@hurleysoftware.com> Sat Apr 09 17:53:25 2016 -0700
committer Greg Kroah-Hartman <gregkh@linuxfoundation.org> Sat Apr 30 09:26:55 2016 -0700
tree 4b09c15500d404b0b375469dd673f0bc8fd05f5f
parent 80f02d5424301bf4df195d09b1a664f394435851

tty: Replace ASYNC_INITIALIZED bit and update atomically

Replace ASYNC_INITIALIZED bit in the tty_port::flags field with
TTY_PORT_INITIALIZED bit in the tty_port::iflags field. Introduce helpers
tty_port_set_initialized() and tty_port_initialized() to abstract
atomic bit ops.

Note: the transforms for test_and_set_bit() and test_and_clear_bit()
are unnecessary as the state transitions are already mutually exclusive;
the tty lock prevents concurrent open/close/hangup.

Signed-off-by: Peter Hurley <peter@hurleysoftware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

net/irda/ircomm/ircomm_tty.c

diff --git a/net/irda/ircomm/ircomm_tty.c b/net/irda/ircomm/ircomm_tty.c
index 5b7ce59..873c4b7 100644
--- a/net/irda/ircomm/ircomm_tty.c
+++ b/net/irda/ircomm/ircomm_tty.c
@@ -220,10 +220,11 @@
 	IRDA_ASSERT(self->magic == IRCOMM_TTY_MAGIC, return -1;);
 
 	/* Check if already open */
-	if (test_and_set_bit(ASYNCB_INITIALIZED, &self->port.flags)) {
+	if (tty_port_initialized(&self->port)) {
 		pr_debug("%s(), already open so break out!\n", __func__);
 		return 0;
 	}
+	tty_port_set_initialized(&self->port, 1);
 
 	/* Register with IrCOMM */
 	irda_notify_init(&notify);
@@ -257,7 +258,7 @@
 
 	return 0;
 err:
-	clear_bit(ASYNCB_INITIALIZED, &self->port.flags);
+	tty_port_set_initialized(&self->port, 0);
 	return ret;
 }
 
@@ -318,13 +319,12 @@
 	spin_unlock_irqrestore(&port->lock, flags);
 
 	while (1) {
-		if (C_BAUD(tty) && test_bit(ASYNCB_INITIALIZED, &port->flags))
+		if (C_BAUD(tty) && tty_port_initialized(port))
 			tty_port_raise_dtr_rts(port);
 
 		set_current_state(TASK_INTERRUPTIBLE);
 
-		if (tty_hung_up_p(filp) ||
-		    !test_bit(ASYNCB_INITIALIZED, &port->flags)) {
+		if (tty_hung_up_p(filp) || !tty_port_initialized(port)) {
 			retval = (port->flags & ASYNC_HUP_NOTIFY) ?
 					-EAGAIN : -ERESTARTSYS;
 			break;
@@ -876,8 +876,9 @@
 	IRDA_ASSERT(self != NULL, return;);
 	IRDA_ASSERT(self->magic == IRCOMM_TTY_MAGIC, return;);
 
-	if (!test_and_clear_bit(ASYNCB_INITIALIZED, &self->port.flags))
+	if (!tty_port_initialized(&self->port))
 		return;
+	tty_port_set_initialized(&self->port, 0);
 
 	ircomm_tty_detach_cable(self);
 
@@ -1259,7 +1260,7 @@
 		seq_printf(m, "%cASYNC_CHECK_CD", sep);
 		sep = '|';
 	}
-	if (self->port.flags & ASYNC_INITIALIZED) {
+	if (tty_port_initialized(&self->port)) {
 		seq_printf(m, "%cASYNC_INITIALIZED", sep);
 		sep = '|';
 	}