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Subject[PATCH 2/3] gigaset: in file ops, check for device disconnect before anything else
Date
When the device is disconnected, the dev structure goes away, so
trying to report another error via dev_printk is bound to oops.
To avoid that, first check whether the device is still connected
and return quietly if it isn't.

Impact: error handling

Signed-off-by: Tilman Schmidt <tilman@imap.cc>
Reported-by: Paul Bolle <pebolle@tiscali.nl>
Tested-by: Paul Bolle <pebolle@tiscali.nl>
---
drivers/isdn/gigaset/interface.c | 58 +++++++++++++++++++------------------
1 files changed, 30 insertions(+), 28 deletions(-)
diff --git a/drivers/isdn/gigaset/interface.c b/drivers/isdn/gigaset/interface.c
index 311e7ca..820a309 100644
--- a/drivers/isdn/gigaset/interface.c
+++ b/drivers/isdn/gigaset/interface.c
@@ -193,7 +193,9 @@ static void if_close(struct tty_struct *tty, struct file *filp)

mutex_lock(&cs->mutex);

- if (!cs->open_count)
+ if (!cs->connected)
+ gig_dbg(DEBUG_IF, "not connected"); /* nothing to do */
+ else if (!cs->open_count)
dev_warn(cs->dev, "%s: device not opened\n", __func__);
else {
if (!--cs->open_count) {
@@ -228,7 +230,10 @@ static int if_ioctl(struct tty_struct *tty, struct file *file,
if (mutex_lock_interruptible(&cs->mutex))
return -ERESTARTSYS; // FIXME -EINTR?

- if (!cs->open_count)
+ if (!cs->connected) {
+ gig_dbg(DEBUG_IF, "not connected");
+ retval = -ENODEV;
+ } else if (!cs->open_count)
dev_warn(cs->dev, "%s: device not opened\n", __func__);
else {
retval = 0;
@@ -248,13 +253,6 @@ static int if_ioctl(struct tty_struct *tty, struct file *file,
retval = put_user(int_arg, (int __user *) arg);
break;
case GIGASET_BRKCHARS:
- //FIXME test if MS_LOCKED
- if (!cs->connected) {
- gig_dbg(DEBUG_ANY,
- "can't communicate with unplugged device");
- retval = -ENODEV;
- break;
- }
retval = copy_from_user(&buf,
(const unsigned char __user *) arg, 6)
? -EFAULT : 0;
@@ -331,7 +329,7 @@ static int if_tiocmset(struct tty_struct *tty, struct file *file,
return -ERESTARTSYS; // FIXME -EINTR?

if (!cs->connected) {
- gig_dbg(DEBUG_ANY, "can't communicate with unplugged device");
+ gig_dbg(DEBUG_IF, "not connected");
retval = -ENODEV;
} else {
mc = (cs->control_state | set) & ~clear & (TIOCM_RTS|TIOCM_DTR);
@@ -360,14 +358,14 @@ static int if_write(struct tty_struct *tty, const unsigned char *buf, int count)
if (mutex_lock_interruptible(&cs->mutex))
return -ERESTARTSYS; // FIXME -EINTR?

- if (!cs->open_count)
+ if (!cs->connected) {
+ gig_dbg(DEBUG_IF, "not connected");
+ retval = -ENODEV;
+ } else if (!cs->open_count)
dev_warn(cs->dev, "%s: device not opened\n", __func__);
else if (cs->mstate != MS_LOCKED) {
dev_warn(cs->dev, "can't write to unlocked device\n");
retval = -EBUSY;
- } else if (!cs->connected) {
- gig_dbg(DEBUG_ANY, "can't write to unplugged device");
- retval = -EBUSY; //FIXME
} else {
retval = cs->ops->write_cmd(cs, buf, count,
&cs->if_wake_tasklet);
@@ -394,14 +392,14 @@ static int if_write_room(struct tty_struct *tty)
if (mutex_lock_interruptible(&cs->mutex))
return -ERESTARTSYS; // FIXME -EINTR?

- if (!cs->open_count)
+ if (!cs->connected) {
+ gig_dbg(DEBUG_IF, "not connected");
+ retval = -ENODEV;
+ } else if (!cs->open_count)
dev_warn(cs->dev, "%s: device not opened\n", __func__);
else if (cs->mstate != MS_LOCKED) {
dev_warn(cs->dev, "can't write to unlocked device\n");
retval = -EBUSY;
- } else if (!cs->connected) {
- gig_dbg(DEBUG_ANY, "can't write to unplugged device");
- retval = -EBUSY; //FIXME
} else
retval = cs->ops->write_room(cs);

@@ -426,14 +424,14 @@ static int if_chars_in_buffer(struct tty_struct *tty)
if (mutex_lock_interruptible(&cs->mutex))
return -ERESTARTSYS; // FIXME -EINTR?

- if (!cs->open_count)
+ if (!cs->connected) {
+ gig_dbg(DEBUG_IF, "not connected");
+ retval = -ENODEV;
+ } else if (!cs->open_count)
dev_warn(cs->dev, "%s: device not opened\n", __func__);
else if (cs->mstate != MS_LOCKED) {
dev_warn(cs->dev, "can't write to unlocked device\n");
retval = -EBUSY;
- } else if (!cs->connected) {
- gig_dbg(DEBUG_ANY, "can't write to unplugged device");
- retval = -EBUSY; //FIXME
} else
retval = cs->ops->chars_in_buffer(cs);

@@ -456,7 +454,9 @@ static void if_throttle(struct tty_struct *tty)

mutex_lock(&cs->mutex);

- if (!cs->open_count)
+ if (!cs->connected)
+ gig_dbg(DEBUG_IF, "not connected"); /* nothing to do */
+ else if (!cs->open_count)
dev_warn(cs->dev, "%s: device not opened\n", __func__);
else {
//FIXME
@@ -479,7 +479,9 @@ static void if_unthrottle(struct tty_struct *tty)

mutex_lock(&cs->mutex);

- if (!cs->open_count)
+ if (!cs->connected)
+ gig_dbg(DEBUG_IF, "not connected"); /* nothing to do */
+ else if (!cs->open_count)
dev_warn(cs->dev, "%s: device not opened\n", __func__);
else {
//FIXME
@@ -506,13 +508,13 @@ static void if_set_termios(struct tty_struct *tty, struct ktermios *old)

mutex_lock(&cs->mutex);

- if (!cs->open_count) {
- dev_warn(cs->dev, "%s: device not opened\n", __func__);
+ if (!cs->connected) {
+ gig_dbg(DEBUG_IF, "not connected");
goto out;
}

- if (!cs->connected) {
- gig_dbg(DEBUG_ANY, "can't communicate with unplugged device");
+ if (!cs->open_count) {
+ dev_warn(cs->dev, "%s: device not opened\n", __func__);
goto out;
}

--
1.6.2.1.214.ge986c


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