gigaset: in file ops, check for device disconnect before anything else

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>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 30 insertions, 28 deletions

diff --git a/drivers/isdn/gigaset/interface.c b/drivers/isdn/gigaset/interface.c
index 311e7ca0fb01..820a30923fee 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;
         }