usb: cdc-acm: bugfix release()

Bugfixes to the usb_driver_release_interface() usage;

  (a) make sure releasing *either* interface first will release
      the other, instead of insisting it be the control interface;

  (b) remove the recently-added self-deadlock.

(The "fix disconnect bug in cdc-acm" patch was incomplete and incorrect.)

Plus a small "sparse" fix:  rename a local variable so it doesn't
shadow a function parameter.

Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Acked-by: Oliver Neukum <oneukum@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 9 insertions, 6 deletions

diff --git a/drivers/usb/class/cdc-acm.c b/drivers/usb/class/cdc-acm.c
index a92395bf5f5b..910247d191e8 100644
--- a/drivers/usb/class/cdc-acm.c
+++ b/drivers/usb/class/cdc-acm.c
@@ -1108,9 +1108,11 @@ skip_normal_probe:
                 rcv->instance = acm;
         }
         for (i = 0; i < num_rx_buf; i++) {
-                struct acm_rb *buf = &(acm->rb[i]);
+                struct acm_rb *rb = &(acm->rb[i]);
 
-                if (!(buf->base = usb_buffer_alloc(acm->dev, readsize, GFP_KERNEL, &buf->dma))) {
+                rb->base = usb_buffer_alloc(acm->dev, readsize,
+                                GFP_KERNEL, &rb->dma);
+                if (!rb->base) {
                         dev_dbg(&intf->dev, "out of memory (read bufs usb_buffer_alloc)\n");
                         goto alloc_fail7;
                 }
@@ -1172,6 +1174,7 @@ skip_countries:
         acm_set_line(acm, &acm->line);
 
         usb_driver_claim_interface(&acm_driver, data_interface, acm);
+        usb_set_intfdata(data_interface, acm);
 
         usb_get_intf(control_interface);
         tty_register_device(acm_tty_driver, minor, &control_interface->dev);
@@ -1221,11 +1224,11 @@ static void acm_disconnect(struct usb_interface *intf)
         struct acm *acm = usb_get_intfdata(intf);
         struct usb_device *usb_dev = interface_to_usbdev(intf);
 
-        mutex_lock(&open_mutex);
-        if (!acm || !acm->dev) {
-                mutex_unlock(&open_mutex);
+        /* sibling interface is already cleaning up */
+        if (!acm)
                 return;
-        }
+
+        mutex_lock(&open_mutex);
         if (acm->country_codes){
                 device_remove_file(&acm->control->dev,
                                 &dev_attr_wCountryCodes);