tty: usb-serial krefs

Use kref in the USB serial drivers so that we don't free tty structures
from under the URB receive handlers as has historically been the case if
you were unlucky. This also gives us a framework for general tty drivers to
use tty_port objects and refcount.

Contains two err->dev_err changes merged together to fix clashes in the
-next tree.

Signed-off-by: Alan Cox <alan@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 40 insertions, 37 deletions

diff --git a/drivers/usb/serial/keyspan.c b/drivers/usb/serial/keyspan.c
index 704716f6f6d3..15447af48691 100644
--- a/drivers/usb/serial/keyspan.c
+++ b/drivers/usb/serial/keyspan.c
@@ -430,7 +430,7 @@ static void	usa26_indat_callback(struct urb *urb)
         }
 
         port =  urb->context;
-        tty = port->port.tty;
+        tty = tty_port_tty_get(&port->port);
         if (tty && urb->actual_length) {
                 /* 0x80 bit is error flag */
                 if ((data[0] & 0x80) == 0) {
@@ -459,6 +459,7 @@ static void	usa26_indat_callback(struct urb *urb)
                 }
                 tty_flip_buffer_push(tty);
         }
+        tty_kref_put(tty);
 
         /* Resubmit urb so we continue receiving */
         urb->dev = port->serial->dev;
@@ -513,6 +514,7 @@ static void	usa26_instat_callback(struct urb *urb)
         struct usb_serial                       *serial;
         struct usb_serial_port                  *port;
         struct keyspan_port_private             *p_priv;
+        struct tty_struct                       *tty;
         int old_dcd_state, err;
         int status = urb->status;
 
@@ -553,12 +555,11 @@ static void	usa26_instat_callback(struct urb *urb)
         p_priv->dcd_state = ((msg->gpia_dcd) ? 1 : 0);
         p_priv->ri_state = ((msg->ri) ? 1 : 0);
 
-        if (port->port.tty && !C_CLOCAL(port->port.tty)
-            && old_dcd_state != p_priv->dcd_state) {
-                if (old_dcd_state)
-                        tty_hangup(port->port.tty);
-                /*  else */
-                /*      wake_up_interruptible(&p_priv->open_wait); */
+        if (old_dcd_state != p_priv->dcd_state) {
+                tty = tty_port_tty_get(&port->port);
+                if (tty && !C_CLOCAL(tty))
+                        tty_hangup(tty);
+                tty_kref_put(tty);
         }
 
         /* Resubmit urb so we continue receiving */
@@ -604,11 +605,12 @@ static void usa28_indat_callback(struct urb *urb)
                 p_priv = usb_get_serial_port_data(port);
                 data = urb->transfer_buffer;
 
-                tty = port->port.tty;
-                if (urb->actual_length) {
+                tty =tty_port_tty_get(&port->port);
+                if (tty && urb->actual_length) {
                         tty_insert_flip_string(tty, data, urb->actual_length);
                         tty_flip_buffer_push(tty);
                 }
+                tty_kref_put(tty);
 
                 /* Resubmit urb so we continue receiving */
                 urb->dev = port->serial->dev;
@@ -652,6 +654,7 @@ static void	usa28_instat_callback(struct urb *urb)
         struct usb_serial                       *serial;
         struct usb_serial_port                  *port;
         struct keyspan_port_private             *p_priv;
+        struct tty_struct                       *tty;
         int old_dcd_state;
         int status = urb->status;
 
@@ -689,12 +692,11 @@ static void	usa28_instat_callback(struct urb *urb)
         p_priv->dcd_state = ((msg->dcd) ? 1 : 0);
         p_priv->ri_state = ((msg->ri) ? 1 : 0);
 
-        if (port->port.tty && !C_CLOCAL(port->port.tty)
-            && old_dcd_state != p_priv->dcd_state) {
-                if (old_dcd_state)
-                        tty_hangup(port->port.tty);
-                /*  else */
-                /*      wake_up_interruptible(&p_priv->open_wait); */
+        if( old_dcd_state != p_priv->dcd_state && old_dcd_state) {
+                tty = tty_port_tty_get(&port->port);
+                if (tty && !C_CLOCAL(tty)) 
+                        tty_hangup(tty);
+                tty_kref_put(tty);
         }
 
                 /* Resubmit urb so we continue receiving */
@@ -785,12 +787,11 @@ static void	usa49_instat_callback(struct urb *urb)
         p_priv->dcd_state = ((msg->dcd) ? 1 : 0);
         p_priv->ri_state = ((msg->ri) ? 1 : 0);
 
-        if (port->port.tty && !C_CLOCAL(port->port.tty)
-            && old_dcd_state != p_priv->dcd_state) {
-                if (old_dcd_state)
-                        tty_hangup(port->port.tty);
-                /*  else */
-                /*      wake_up_interruptible(&p_priv->open_wait); */
+        if (old_dcd_state != p_priv->dcd_state && old_dcd_state) {
+                struct tty_struct *tty = tty_port_tty_get(&port->port);
+                if (tty && !C_CLOCAL(tty))
+                        tty_hangup(tty);
+                tty_kref_put(tty);
         }
 
         /* Resubmit urb so we continue receiving */
@@ -827,7 +828,7 @@ static void	usa49_indat_callback(struct urb *urb)
         }
 
         port =  urb->context;
-        tty = port->port.tty;
+        tty = tty_port_tty_get(&port->port);
         if (tty && urb->actual_length) {
                 /* 0x80 bit is error flag */
                 if ((data[0] & 0x80) == 0) {
@@ -850,6 +851,7 @@ static void	usa49_indat_callback(struct urb *urb)
                 }
                 tty_flip_buffer_push(tty);
         }
+        tty_kref_put(tty);
 
         /* Resubmit urb so we continue receiving */
         urb->dev = port->serial->dev;
@@ -893,7 +895,7 @@ static void usa49wg_indat_callback(struct urb *urb)
                                 return;
                         }
                         port = serial->port[data[i++]];
-                        tty = port->port.tty;
+                        tty = tty_port_tty_get(&port->port);
                         len = data[i++];
 
                         /* 0x80 bit is error flag */
@@ -927,6 +929,7 @@ static void usa49wg_indat_callback(struct urb *urb)
                         }
                         if (port->port.count)
                                 tty_flip_buffer_push(tty);
+                        tty_kref_put(tty);
                 }
         }
 
@@ -967,8 +970,8 @@ static void usa90_indat_callback(struct urb *urb)
         port =  urb->context;
         p_priv = usb_get_serial_port_data(port);
 
-        tty = port->port.tty;
         if (urb->actual_length) {
+                tty = tty_port_tty_get(&port->port);
                 /* if current mode is DMA, looks like usa28 format
                    otherwise looks like usa26 data format */
 
@@ -1004,6 +1007,7 @@ static void usa90_indat_callback(struct urb *urb)
                         }
                 }
                 tty_flip_buffer_push(tty);
+                tty_kref_put(tty);
         }
 
         /* Resubmit urb so we continue receiving */
@@ -1025,6 +1029,7 @@ static void	usa90_instat_callback(struct urb *urb)
         struct usb_serial                       *serial;
         struct usb_serial_port                  *port;
         struct keyspan_port_private             *p_priv;
+        struct tty_struct                       *tty;
         int old_dcd_state, err;
         int status = urb->status;
 
@@ -1053,12 +1058,11 @@ static void	usa90_instat_callback(struct urb *urb)
         p_priv->dcd_state = ((msg->dcd) ? 1 : 0);
         p_priv->ri_state = ((msg->ri) ? 1 : 0);
 
-        if (port->port.tty && !C_CLOCAL(port->port.tty)
-            && old_dcd_state != p_priv->dcd_state) {
-                if (old_dcd_state)
-                        tty_hangup(port->port.tty);
-                /*  else */
-                /*      wake_up_interruptible(&p_priv->open_wait); */
+        if (old_dcd_state != p_priv->dcd_state && old_dcd_state) {
+                tty = tty_port_tty_get(&port->port);
+                if (tty && !C_CLOCAL(tty))
+                        tty_hangup(tty);
+                tty_kref_put(tty);
         }
 
         /* Resubmit urb so we continue receiving */
@@ -1130,12 +1134,11 @@ static void	usa67_instat_callback(struct urb *urb)
         p_priv->cts_state = ((msg->hskia_cts) ? 1 : 0);
         p_priv->dcd_state = ((msg->gpia_dcd) ? 1 : 0);
 
-        if (port->port.tty && !C_CLOCAL(port->port.tty)
-            && old_dcd_state != p_priv->dcd_state) {
-                if (old_dcd_state)
-                        tty_hangup(port->port.tty);
-                /*  else */
-                /*      wake_up_interruptible(&p_priv->open_wait); */
+        if (old_dcd_state != p_priv->dcd_state && old_dcd_state) {
+                struct tty_struct *tty = tty_port_tty_get(&port->port);
+                if (tty && !C_CLOCAL(tty))
+                        tty_hangup(tty);
+                tty_kref_put(tty);
         }
 
         /* Resubmit urb so we continue receiving */
@@ -1332,7 +1335,7 @@ static void keyspan_close(struct tty_struct *tty,
                         stop_urb(p_priv->out_urbs[i]);
                 }
         }
-        port->port.tty = NULL;
+        tty_port_tty_set(&port->port, NULL);
 }
 
 /* download the firmware to a pre-renumeration device */