tty: kref usage for isicom and moxa
Rather than blindly keep taking krefs we reorder the code in a few places
to pass the tty down to the right place (which is important as from the user
side it is not the case that tty == port->tty in all situations). For the irq
and related paths use the krefs to stop the tty being freed under us.
Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/drivers/char/isicom.c b/drivers/char/isicom.c
index 8f7cc19..7d30ee1 100644
--- a/drivers/char/isicom.c
+++ b/drivers/char/isicom.c
@@ -421,17 +421,16 @@
if (retries >= 100)
goto unlock;
+ tty = tty_port_tty_get(&port->port);
+ if (tty == NULL)
+ goto put_unlock;
+
for (; count > 0; count--, port++) {
/* port not active or tx disabled to force flow control */
if (!(port->port.flags & ASYNC_INITIALIZED) ||
!(port->status & ISI_TXOK))
continue;
- tty = port->port.tty;
-
- if (tty == NULL)
- continue;
-
txcount = min_t(short, TX_SIZE, port->xmit_cnt);
if (txcount <= 0 || tty->stopped || tty->hw_stopped)
continue;
@@ -489,6 +488,8 @@
tty_wakeup(tty);
}
+put_unlock:
+ tty_kref_put(tty);
unlock:
spin_unlock_irqrestore(&isi_card[card].card_lock, flags);
/* schedule another tx for hopefully in about 10ms */
@@ -547,7 +548,7 @@
return IRQ_HANDLED;
}
- tty = port->port.tty;
+ tty = tty_port_tty_get(&port->port);
if (tty == NULL) {
word_count = byte_count >> 1;
while (byte_count > 1) {
@@ -588,7 +589,7 @@
}
if (port->port.flags & ASYNC_CTS_FLOW) {
- if (port->port.tty->hw_stopped) {
+ if (tty->hw_stopped) {
if (header & ISI_CTS) {
port->port.tty->hw_stopped = 0;
/* start tx ing */
@@ -597,7 +598,7 @@
tty_wakeup(tty);
}
} else if (!(header & ISI_CTS)) {
- port->port.tty->hw_stopped = 1;
+ tty->hw_stopped = 1;
/* stop tx ing */
port->status &= ~(ISI_TXOK | ISI_CTS);
}
@@ -660,24 +661,21 @@
}
outw(0x0000, base+0x04); /* enable interrupts */
spin_unlock(&card->card_lock);
+ tty_kref_put(tty);
return IRQ_HANDLED;
}
-static void isicom_config_port(struct isi_port *port)
+static void isicom_config_port(struct tty_struct *tty)
{
+ struct isi_port *port = tty->driver_data;
struct isi_board *card = port->card;
- struct tty_struct *tty;
unsigned long baud;
unsigned long base = card->base;
u16 channel_setup, channel = port->channel,
shift_count = card->shift_count;
unsigned char flow_ctrl;
- tty = port->port.tty;
-
- if (tty == NULL)
- return;
/* FIXME: Switch to new tty baud API */
baud = C_BAUD(tty);
if (baud & CBAUDEX) {
@@ -690,7 +688,7 @@
/* 1,2,3,4 => 57.6, 115.2, 230, 460 kbps resp. */
if (baud < 1 || baud > 4)
- port->port.tty->termios->c_cflag &= ~CBAUDEX;
+ tty->termios->c_cflag &= ~CBAUDEX;
else
baud += 15;
}
@@ -797,8 +795,9 @@
spin_unlock_irqrestore(&bp->card_lock, flags);
}
-static int isicom_setup_port(struct isi_port *port)
+static int isicom_setup_port(struct tty_struct *tty)
{
+ struct isi_port *port = tty->driver_data;
struct isi_board *card = port->card;
unsigned long flags;
@@ -808,8 +807,7 @@
return -ENOMEM;
spin_lock_irqsave(&card->card_lock, flags);
- if (port->port.tty)
- clear_bit(TTY_IO_ERROR, &port->port.tty->flags);
+ clear_bit(TTY_IO_ERROR, &tty->flags);
if (port->port.count == 1)
card->count++;
@@ -823,7 +821,7 @@
InterruptTheCard(card->base);
}
- isicom_config_port(port);
+ isicom_config_port(tty);
port->port.flags |= ASYNC_INITIALIZED;
spin_unlock_irqrestore(&card->card_lock, flags);
@@ -934,8 +932,8 @@
port->port.count++;
tty->driver_data = port;
- port->port.tty = tty;
- error = isicom_setup_port(port);
+ tty_port_tty_set(&port->port, tty);
+ error = isicom_setup_port(tty);
if (error == 0)
error = block_til_ready(tty, filp, port);
return error;
@@ -955,15 +953,17 @@
struct isi_board *card = port->card;
struct tty_struct *tty;
- tty = port->port.tty;
+ tty = tty_port_tty_get(&port->port);
- if (!(port->port.flags & ASYNC_INITIALIZED))
+ if (!(port->port.flags & ASYNC_INITIALIZED)) {
+ tty_kref_put(tty);
return;
+ }
tty_port_free_xmit_buf(&port->port);
port->port.flags &= ~ASYNC_INITIALIZED;
/* 3rd October 2000 : Vinayak P Risbud */
- port->port.tty = NULL;
+ tty_port_tty_set(&port->port, NULL);
/*Fix done by Anil .S on 30-04-2001
remote login through isi port has dtr toggle problem
@@ -1243,9 +1243,10 @@
return 0;
}
-static int isicom_set_serial_info(struct isi_port *port,
- struct serial_struct __user *info)
+static int isicom_set_serial_info(struct tty_struct *tty,
+ struct serial_struct __user *info)
{
+ struct isi_port *port = tty->driver_data;
struct serial_struct newinfo;
int reconfig_port;
@@ -1276,7 +1277,7 @@
if (reconfig_port) {
unsigned long flags;
spin_lock_irqsave(&port->card->card_lock, flags);
- isicom_config_port(port);
+ isicom_config_port(tty);
spin_unlock_irqrestore(&port->card->card_lock, flags);
}
unlock_kernel();
@@ -1318,7 +1319,7 @@
return isicom_get_serial_info(port, argp);
case TIOCSSERIAL:
- return isicom_set_serial_info(port, argp);
+ return isicom_set_serial_info(tty, argp);
default:
return -ENOIOCTLCMD;
@@ -1341,7 +1342,7 @@
return;
spin_lock_irqsave(&port->card->card_lock, flags);
- isicom_config_port(port);
+ isicom_config_port(tty);
spin_unlock_irqrestore(&port->card->card_lock, flags);
if ((old_termios->c_cflag & CRTSCTS) &&
@@ -1419,7 +1420,7 @@
port->port.count = 0;
port->port.flags &= ~ASYNC_NORMAL_ACTIVE;
- port->port.tty = NULL;
+ tty_port_tty_set(&port->port, NULL);
wake_up_interruptible(&port->port.open_wait);
}
