1 files changed, 16 insertions, 5 deletions

diff --git a/drivers/usb/class/cdc-wdm.c b/drivers/usb/class/cdc-wdm.c
index 86ee39db013f..16e7fa4d488d 100644
--- a/drivers/usb/class/cdc-wdm.c
+++ b/drivers/usb/class/cdc-wdm.c
@@ -726,7 +726,7 @@ static int wdm_open(struct inode *inode, struct file *file)
 		rv = -EBUSY;
 		goto out;
 	}
-
+	smp_rmb(); /* ordered against wdm_wwan_port_stop() */
 	rv = usb_autopm_get_interface(desc->intf);
 	if (rv < 0) {
 		dev_err(&desc->intf->dev, "Error autopm - %d\n", rv);
@@ -829,6 +829,7 @@ static struct usb_class_driver wdm_class = {
 static int wdm_wwan_port_start(struct wwan_port *port)
 {
 	struct wdm_device *desc = wwan_port_get_drvdata(port);
+	int rv;
 
 	/* The interface is both exposed via the WWAN framework and as a
 	 * legacy usbmisc chardev. If chardev is already open, just fail
@@ -848,7 +849,15 @@ static int wdm_wwan_port_start(struct wwan_port *port)
 	wwan_port_txon(port);
 
 	/* Start getting events */
-	return usb_submit_urb(desc->validity, GFP_KERNEL);
+	rv = usb_submit_urb(desc->validity, GFP_KERNEL);
+	if (rv < 0) {
+		wwan_port_txoff(port);
+		desc->manage_power(desc->intf, 0);
+		/* this must be last lest we race with chardev open */
+		clear_bit(WDM_WWAN_IN_USE, &desc->flags);
+	}
+
+	return rv;
 }
 
 static void wdm_wwan_port_stop(struct wwan_port *port)
@@ -859,8 +868,10 @@ static void wdm_wwan_port_stop(struct wwan_port *port)
 	poison_urbs(desc);
 	desc->manage_power(desc->intf, 0);
 	clear_bit(WDM_READ, &desc->flags);
-	clear_bit(WDM_WWAN_IN_USE, &desc->flags);
 	unpoison_urbs(desc);
+	smp_wmb(); /* ordered against wdm_open() */
+	/* this must be last lest we open a poisoned device */
+	clear_bit(WDM_WWAN_IN_USE, &desc->flags);
 }
 
 static void wdm_wwan_port_tx_complete(struct urb *urb)
@@ -868,7 +879,7 @@ static void wdm_wwan_port_tx_complete(struct urb *urb)
 	struct sk_buff *skb = urb->context;
 	struct wdm_device *desc = skb_shinfo(skb)->destructor_arg;
 
-	usb_autopm_put_interface(desc->intf);
+	usb_autopm_put_interface_async(desc->intf);
 	wwan_port_txon(desc->wwanp);
 	kfree_skb(skb);
 }
@@ -898,7 +909,7 @@ static int wdm_wwan_port_tx(struct wwan_port *port, struct sk_buff *skb)
 	req->bRequestType = (USB_DIR_OUT | USB_TYPE_CLASS | USB_RECIP_INTERFACE);
 	req->bRequest = USB_CDC_SEND_ENCAPSULATED_COMMAND;
 	req->wValue = 0;
-	req->wIndex = desc->inum;
+	req->wIndex = desc->inum; /* already converted */
 	req->wLength = cpu_to_le16(skb->len);
 
 	skb_shinfo(skb)->destructor_arg = desc;