3 files changed, 24 insertions, 14 deletions

diff --git a/drivers/usb/class/Kconfig b/drivers/usb/class/Kconfig
index 2519e320098..316aac8e4ca 100644
--- a/drivers/usb/class/Kconfig
+++ b/drivers/usb/class/Kconfig
@@ -6,7 +6,7 @@ comment "USB Device Class drivers"
 
 config USB_ACM
 	tristate "USB Modem (CDC ACM) support"
-	depends on USB
+	depends on USB && TTY
 	---help---
 	  This driver supports USB modems and ISDN adapters which support the
 	  Communication Device Class Abstract Control Model interface.
diff --git a/drivers/usb/class/cdc-acm.c b/drivers/usb/class/cdc-acm.c
index 2d92cce260d..8ac25adf31b 100644
--- a/drivers/usb/class/cdc-acm.c
+++ b/drivers/usb/class/cdc-acm.c
@@ -410,19 +410,12 @@ static int acm_submit_read_urbs(struct acm *acm, gfp_t mem_flags)
 
 static void acm_process_read_urb(struct acm *acm, struct urb *urb)
 {
-	struct tty_struct *tty;
-
 	if (!urb->actual_length)
 		return;
 
-	tty = tty_port_tty_get(&acm->port);
-	if (!tty)
-		return;
-
-	tty_insert_flip_string(tty, urb->transfer_buffer, urb->actual_length);
-	tty_flip_buffer_push(tty);
-
-	tty_kref_put(tty);
+	tty_insert_flip_string(&acm->port, urb->transfer_buffer,
+			urb->actual_length);
+	tty_flip_buffer_push(&acm->port);
 }
 
 static void acm_read_bulk_callback(struct urb *urb)
diff --git a/drivers/usb/class/cdc-wdm.c b/drivers/usb/class/cdc-wdm.c
index 5f0cb417b73..122d056d96d 100644
--- a/drivers/usb/class/cdc-wdm.c
+++ b/drivers/usb/class/cdc-wdm.c
@@ -56,6 +56,7 @@ MODULE_DEVICE_TABLE (usb, wdm_ids);
 #define WDM_RESPONDING		7
 #define WDM_SUSPENDING		8
 #define WDM_RESETTING		9
+#define WDM_OVERFLOW		10
 
 #define WDM_MAX			16
 
@@ -155,6 +156,7 @@ static void wdm_in_callback(struct urb *urb)
 {
 	struct wdm_device *desc = urb->context;
 	int status = urb->status;
+	int length = urb->actual_length;
 
 	spin_lock(&desc->iuspin);
 	clear_bit(WDM_RESPONDING, &desc->flags);
@@ -185,9 +187,17 @@ static void wdm_in_callback(struct urb *urb)
 	}
 
 	desc->rerr = status;
-	desc->reslength = urb->actual_length;
-	memmove(desc->ubuf + desc->length, desc->inbuf, desc->reslength);
-	desc->length += desc->reslength;
+	if (length + desc->length > desc->wMaxCommand) {
+		/* The buffer would overflow */
+		set_bit(WDM_OVERFLOW, &desc->flags);
+	} else {
+		/* we may already be in overflow */
+		if (!test_bit(WDM_OVERFLOW, &desc->flags)) {
+			memmove(desc->ubuf + desc->length, desc->inbuf, length);
+			desc->length += length;
+			desc->reslength = length;
+		}
+	}
 skip_error:
 	wake_up(&desc->wait);
 
@@ -435,6 +445,11 @@ retry:
 			rv = -ENODEV;
 			goto err;
 		}
+		if (test_bit(WDM_OVERFLOW, &desc->flags)) {
+			clear_bit(WDM_OVERFLOW, &desc->flags);
+			rv = -ENOBUFS;
+			goto err;
+		}
 		i++;
 		if (file->f_flags & O_NONBLOCK) {
 			if (!test_bit(WDM_READ, &desc->flags)) {
@@ -478,6 +493,7 @@ retry:
 			spin_unlock_irq(&desc->iuspin);
 			goto retry;
 		}
+
 		if (!desc->reslength) { /* zero length read */
 			dev_dbg(&desc->intf->dev, "%s: zero length - clearing WDM_READ\n", __func__);
 			clear_bit(WDM_READ, &desc->flags);
@@ -1004,6 +1020,7 @@ static int wdm_post_reset(struct usb_interface *intf)
 	struct wdm_device *desc = wdm_find_device(intf);
 	int rv;
 
+	clear_bit(WDM_OVERFLOW, &desc->flags);
 	clear_bit(WDM_RESETTING, &desc->flags);
 	rv = recover_from_urb_loss(desc);
 	mutex_unlock(&desc->wlock);