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Subject[PATCH 07/24] TTY: ircomm, use tty from tty_port
Date
This also includes a switch to tty refcounting. It makes sure, the
code no longer can access a freed TTY struct.

Sometimes the only thing needed is to pass tty down to the callies.

Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Cc: Samuel Ortiz <samuel@sortiz.org>
Cc: netdev@vger.kernel.org
---
include/net/irda/ircomm_tty.h | 1 -
net/irda/ircomm/ircomm_param.c | 5 ---
net/irda/ircomm/ircomm_tty.c | 62 ++++++++++++++++++++++-------------
net/irda/ircomm/ircomm_tty_attach.c | 33 ++++++++++++++-----
net/irda/ircomm/ircomm_tty_ioctl.c | 11 ++++---
5 files changed, 70 insertions(+), 42 deletions(-)
diff --git a/include/net/irda/ircomm_tty.h b/include/net/irda/ircomm_tty.h
index a9027d8..80ffde3 100644
--- a/include/net/irda/ircomm_tty.h
+++ b/include/net/irda/ircomm_tty.h
@@ -62,7 +62,6 @@ struct ircomm_tty_cb {

int state; /* Connect state */

- struct tty_struct *tty;
struct ircomm_cb *ircomm; /* IrCOMM layer instance */

struct sk_buff *tx_skb; /* Transmit buffer */
diff --git a/net/irda/ircomm/ircomm_param.c b/net/irda/ircomm/ircomm_param.c
index 8b915f3..3089391 100644
--- a/net/irda/ircomm/ircomm_param.c
+++ b/net/irda/ircomm/ircomm_param.c
@@ -99,7 +99,6 @@ pi_param_info_t ircomm_param_info = { pi_major_call_table, 3, 0x0f, 4 };
*/
int ircomm_param_request(struct ircomm_tty_cb *self, __u8 pi, int flush)
{
- struct tty_struct *tty;
unsigned long flags;
struct sk_buff *skb;
int count;
@@ -109,10 +108,6 @@ int ircomm_param_request(struct ircomm_tty_cb *self, __u8 pi, int flush)
IRDA_ASSERT(self != NULL, return -1;);
IRDA_ASSERT(self->magic == IRCOMM_TTY_MAGIC, return -1;);

- tty = self->tty;
- if (!tty)
- return 0;
-
/* Make sure we don't send parameters for raw mode */
if (self->service_type == IRCOMM_3_WIRE_RAW)
return 0;
diff --git a/net/irda/ircomm/ircomm_tty.c b/net/irda/ircomm/ircomm_tty.c
index 7b2152c..03acc07 100644
--- a/net/irda/ircomm/ircomm_tty.c
+++ b/net/irda/ircomm/ircomm_tty.c
@@ -242,18 +242,15 @@ err:
*
*/
static int ircomm_tty_block_til_ready(struct ircomm_tty_cb *self,
- struct file *filp)
+ struct tty_struct *tty, struct file *filp)
{
DECLARE_WAITQUEUE(wait, current);
int retval;
int do_clocal = 0, extra_count = 0;
unsigned long flags;
- struct tty_struct *tty;

IRDA_DEBUG(2, "%s()\n", __func__ );

- tty = self->tty;
-
/*
* If non-blocking mode is set, or the port is not enabled,
* then make the check up front and then exit.
@@ -412,8 +409,8 @@ static int ircomm_tty_open(struct tty_struct *tty, struct file *filp)
self->port.count++;

tty->driver_data = self;
- self->tty = tty;
spin_unlock_irqrestore(&self->port.lock, flags);
+ tty_port_tty_set(&self->port, tty);

IRDA_DEBUG(1, "%s(), %s%d, count = %d\n", __func__ , tty->driver->name,
self->line, self->port.count);
@@ -467,7 +464,7 @@ static int ircomm_tty_open(struct tty_struct *tty, struct file *filp)
if (ret)
return ret;

- ret = ircomm_tty_block_til_ready(self, filp);
+ ret = ircomm_tty_block_til_ready(self, tty, filp);
if (ret) {
IRDA_DEBUG(2,
"%s(), returning after block_til_ready with %d\n", __func__ ,
@@ -548,7 +545,6 @@ static void ircomm_tty_close(struct tty_struct *tty, struct file *filp)

spin_lock_irqsave(&self->port.lock, flags);
tty->closing = 0;
- self->tty = NULL;

if (self->port.blocked_open) {
if (self->port.close_delay) {
@@ -562,6 +558,7 @@ static void ircomm_tty_close(struct tty_struct *tty, struct file *filp)
self->port.flags &= ~(ASYNC_NORMAL_ACTIVE|ASYNC_CLOSING);
spin_unlock_irqrestore(&self->port.lock, flags);
wake_up_interruptible(&self->port.close_wait);
+ tty_port_tty_set(&self->port, NULL);
}

/*
@@ -604,7 +601,7 @@ static void ircomm_tty_do_softint(struct work_struct *work)
if (!self || self->magic != IRCOMM_TTY_MAGIC)
return;

- tty = self->tty;
+ tty = tty_port_tty_get(&self->port);
if (!tty)
return;

@@ -625,7 +622,7 @@ static void ircomm_tty_do_softint(struct work_struct *work)
}

if (tty->hw_stopped)
- return;
+ goto put;

/* Unlink transmit buffer */
spin_lock_irqsave(&self->spinlock, flags);
@@ -644,6 +641,8 @@ static void ircomm_tty_do_softint(struct work_struct *work)

/* Check if user (still) wants to be waken up */
tty_wakeup(tty);
+put:
+ tty_kref_put(tty);
}

/*
@@ -1004,7 +1003,11 @@ static void ircomm_tty_hangup(struct tty_struct *tty)

spin_lock_irqsave(&self->port.lock, flags);
self->port.flags &= ~ASYNC_NORMAL_ACTIVE;
- self->tty = NULL;
+ if (self->port.tty) {
+ set_bit(TTY_IO_ERROR, &self->port.tty->flags);
+ tty_kref_put(self->port.tty);
+ }
+ self->port.tty = NULL;
self->port.count = 0;
spin_unlock_irqrestore(&self->port.lock, flags);

@@ -1068,7 +1071,7 @@ void ircomm_tty_check_modem_status(struct ircomm_tty_cb *self)
IRDA_ASSERT(self != NULL, return;);
IRDA_ASSERT(self->magic == IRCOMM_TTY_MAGIC, return;);

- tty = self->tty;
+ tty = tty_port_tty_get(&self->port);

status = self->settings.dce;

@@ -1089,10 +1092,10 @@ void ircomm_tty_check_modem_status(struct ircomm_tty_cb *self)
tty_hangup(tty);

/* Hangup will remote the tty, so better break out */
- return;
+ goto put;
}
}
- if (self->port.flags & ASYNC_CTS_FLOW) {
+ if (tty && self->port.flags & ASYNC_CTS_FLOW) {
if (tty->hw_stopped) {
if (status & IRCOMM_CTS) {
IRDA_DEBUG(2,
@@ -1103,7 +1106,7 @@ void ircomm_tty_check_modem_status(struct ircomm_tty_cb *self)
wake_up_interruptible(&self->port.open_wait);

schedule_work(&self->tqueue);
- return;
+ goto put;
}
} else {
if (!(status & IRCOMM_CTS)) {
@@ -1113,6 +1116,8 @@ void ircomm_tty_check_modem_status(struct ircomm_tty_cb *self)
}
}
}
+put:
+ tty_kref_put(tty);
}

/*
@@ -1125,6 +1130,7 @@ static int ircomm_tty_data_indication(void *instance, void *sap,
struct sk_buff *skb)
{
struct ircomm_tty_cb *self = (struct ircomm_tty_cb *) instance;
+ struct tty_struct *tty;

IRDA_DEBUG(2, "%s()\n", __func__ );

@@ -1132,7 +1138,8 @@ static int ircomm_tty_data_indication(void *instance, void *sap,
IRDA_ASSERT(self->magic == IRCOMM_TTY_MAGIC, return -1;);
IRDA_ASSERT(skb != NULL, return -1;);

- if (!self->tty) {
+ tty = tty_port_tty_get(&self->port);
+ if (!tty) {
IRDA_DEBUG(0, "%s(), no tty!\n", __func__ );
return 0;
}
@@ -1143,7 +1150,7 @@ static int ircomm_tty_data_indication(void *instance, void *sap,
* Devices like WinCE can do this, and since they don't send any
* params, we can just as well declare the hardware for running.
*/
- if (self->tty->hw_stopped && (self->flow == FLOW_START)) {
+ if (tty->hw_stopped && (self->flow == FLOW_START)) {
IRDA_DEBUG(0, "%s(), polling for line settings!\n", __func__ );
ircomm_param_request(self, IRCOMM_POLL, TRUE);

@@ -1156,8 +1163,9 @@ static int ircomm_tty_data_indication(void *instance, void *sap,
* Use flip buffer functions since the code may be called from interrupt
* context
*/
- tty_insert_flip_string(self->tty, skb->data, skb->len);
- tty_flip_buffer_push(self->tty);
+ tty_insert_flip_string(tty, skb->data, skb->len);
+ tty_flip_buffer_push(tty);
+ tty_kref_put(tty);

/* No need to kfree_skb - see ircomm_ttp_data_indication() */

@@ -1208,12 +1216,13 @@ static void ircomm_tty_flow_indication(void *instance, void *sap,
IRDA_ASSERT(self != NULL, return;);
IRDA_ASSERT(self->magic == IRCOMM_TTY_MAGIC, return;);

- tty = self->tty;
+ tty = tty_port_tty_get(&self->port);

switch (cmd) {
case FLOW_START:
IRDA_DEBUG(2, "%s(), hw start!\n", __func__ );
- tty->hw_stopped = 0;
+ if (tty)
+ tty->hw_stopped = 0;

/* ircomm_tty_do_softint will take care of the rest */
schedule_work(&self->tqueue);
@@ -1221,15 +1230,19 @@ static void ircomm_tty_flow_indication(void *instance, void *sap,
default: /* If we get here, something is very wrong, better stop */
case FLOW_STOP:
IRDA_DEBUG(2, "%s(), hw stopped!\n", __func__ );
- tty->hw_stopped = 1;
+ if (tty)
+ tty->hw_stopped = 1;
break;
}
+
+ tty_kref_put(tty);
self->flow = cmd;
}

#ifdef CONFIG_PROC_FS
static void ircomm_tty_line_info(struct ircomm_tty_cb *self, struct seq_file *m)
{
+ struct tty_struct *tty;
char sep;

seq_printf(m, "State: %s\n", ircomm_tty_state[self->state]);
@@ -1356,9 +1369,12 @@ static void ircomm_tty_line_info(struct ircomm_tty_cb *self, struct seq_file *m)
seq_printf(m, "Max data size: %d\n", self->max_data_size);
seq_printf(m, "Max header size: %d\n", self->max_header_size);

- if (self->tty)
+ tty = tty_port_tty_get(&self->port);
+ if (tty) {
seq_printf(m, "Hardware: %s\n",
- self->tty->hw_stopped ? "Stopped" : "Running");
+ tty->hw_stopped ? "Stopped" : "Running");
+ tty_kref_put(tty);
+ }
}

static int ircomm_tty_proc_show(struct seq_file *m, void *v)
diff --git a/net/irda/ircomm/ircomm_tty_attach.c b/net/irda/ircomm/ircomm_tty_attach.c
index bed311a..3ab70e7 100644
--- a/net/irda/ircomm/ircomm_tty_attach.c
+++ b/net/irda/ircomm/ircomm_tty_attach.c
@@ -130,6 +130,8 @@ static int (*state[])(struct ircomm_tty_cb *self, IRCOMM_TTY_EVENT event,
*/
int ircomm_tty_attach_cable(struct ircomm_tty_cb *self)
{
+ struct tty_struct *tty;
+
IRDA_DEBUG(0, "%s()\n", __func__ );

IRDA_ASSERT(self != NULL, return -1;);
@@ -142,7 +144,11 @@ int ircomm_tty_attach_cable(struct ircomm_tty_cb *self)
}

/* Make sure nobody tries to write before the link is up */
- self->tty->hw_stopped = 1;
+ tty = tty_port_tty_get(&self->port);
+ if (tty) {
+ tty->hw_stopped = 1;
+ tty_kref_put(tty);
+ }

ircomm_tty_ias_register(self);

@@ -398,23 +404,26 @@ void ircomm_tty_disconnect_indication(void *instance, void *sap,
struct sk_buff *skb)
{
struct ircomm_tty_cb *self = (struct ircomm_tty_cb *) instance;
+ struct tty_struct *tty;

IRDA_DEBUG(2, "%s()\n", __func__ );

IRDA_ASSERT(self != NULL, return;);
IRDA_ASSERT(self->magic == IRCOMM_TTY_MAGIC, return;);

- if (!self->tty)
+ tty = tty_port_tty_get(&self->port);
+ if (!tty)
return;

/* This will stop control data transfers */
self->flow = FLOW_STOP;

/* Stop data transfers */
- self->tty->hw_stopped = 1;
+ tty->hw_stopped = 1;

ircomm_tty_do_event(self, IRCOMM_TTY_DISCONNECT_INDICATION, NULL,
NULL);
+ tty_kref_put(tty);
}

/*
@@ -550,12 +559,15 @@ void ircomm_tty_connect_indication(void *instance, void *sap,
*/
void ircomm_tty_link_established(struct ircomm_tty_cb *self)
{
+ struct tty_struct *tty;
+
IRDA_DEBUG(2, "%s()\n", __func__ );

IRDA_ASSERT(self != NULL, return;);
IRDA_ASSERT(self->magic == IRCOMM_TTY_MAGIC, return;);

- if (!self->tty)
+ tty = tty_port_tty_get(&self->port);
+ if (!tty)
return;

del_timer(&self->watchdog_timer);
@@ -569,17 +581,19 @@ void ircomm_tty_link_established(struct ircomm_tty_cb *self)
if ((self->port.flags & ASYNC_CTS_FLOW) &&
((self->settings.dce & IRCOMM_CTS) == 0)) {
IRDA_DEBUG(0, "%s(), waiting for CTS ...\n", __func__ );
- return;
+ goto put;
} else {
IRDA_DEBUG(1, "%s(), starting hardware!\n", __func__ );

- self->tty->hw_stopped = 0;
+ tty->hw_stopped = 0;

/* Wake up processes blocked on open */
wake_up_interruptible(&self->port.open_wait);
}

schedule_work(&self->tqueue);
+put:
+ tty_kref_put(tty);
}

/*
@@ -983,9 +997,12 @@ static int ircomm_tty_state_ready(struct ircomm_tty_cb *self,
self->settings.dce = IRCOMM_DELTA_CD;
ircomm_tty_check_modem_status(self);
} else {
+ struct tty_struct *tty = tty_port_tty_get(&self->port);
IRDA_DEBUG(0, "%s(), hanging up!\n", __func__ );
- if (self->tty)
- tty_hangup(self->tty);
+ if (tty) {
+ tty_hangup(tty);
+ tty_kref_put(tty);
+ }
}
break;
default:
diff --git a/net/irda/ircomm/ircomm_tty_ioctl.c b/net/irda/ircomm/ircomm_tty_ioctl.c
index 31b917e..0eab650 100644
--- a/net/irda/ircomm/ircomm_tty_ioctl.c
+++ b/net/irda/ircomm/ircomm_tty_ioctl.c
@@ -52,17 +52,18 @@
* Change speed of the driver. If the remote device is a DCE, then this
* should make it change the speed of its serial port
*/
-static void ircomm_tty_change_speed(struct ircomm_tty_cb *self)
+static void ircomm_tty_change_speed(struct ircomm_tty_cb *self,
+ struct tty_struct *tty)
{
unsigned int cflag, cval;
int baud;

IRDA_DEBUG(2, "%s()\n", __func__ );

- if (!self->tty || !self->tty->termios || !self->ircomm)
+ if (!self->ircomm)
return;

- cflag = self->tty->termios->c_cflag;
+ cflag = tty->termios->c_cflag;

/* byte size and parity */
switch (cflag & CSIZE) {
@@ -81,7 +82,7 @@ static void ircomm_tty_change_speed(struct ircomm_tty_cb *self)
cval |= IRCOMM_PARITY_EVEN;

/* Determine divisor based on baud rate */
- baud = tty_get_baud_rate(self->tty);
+ baud = tty_get_baud_rate(tty);
if (!baud)
baud = 9600; /* B0 transition handled in rs_set_termios */

@@ -159,7 +160,7 @@ void ircomm_tty_set_termios(struct tty_struct *tty,
return;
}

- ircomm_tty_change_speed(self);
+ ircomm_tty_change_speed(self, tty);

/* Handle transition to B0 status */
if ((old_termios->c_cflag & CBAUD) &&
--
1.7.10.3



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