USB: uas: Ensure we only bind to a UAS interface
While all existing UAS devices use alternate interface 1, this is not
guaranteed, and it has caused confusion with people trying to bind the
uas driver to non-uas devices.
Signed-off-by: Matthew Wilcox <willy@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
diff --git a/drivers/usb/storage/uas.c b/drivers/usb/storage/uas.c
index 06409a6..52e5ec1 100644
--- a/drivers/usb/storage/uas.c
+++ b/drivers/usb/storage/uas.c
@@ -582,6 +582,34 @@
};
MODULE_DEVICE_TABLE(usb, uas_usb_ids);
+static int uas_is_interface(struct usb_host_interface *intf)
+{
+ return (intf->desc.bInterfaceClass == USB_CLASS_MASS_STORAGE &&
+ intf->desc.bInterfaceSubClass == USB_SC_SCSI &&
+ intf->desc.bInterfaceProtocol == USB_PR_UAS);
+}
+
+static int uas_switch_interface(struct usb_device *udev,
+ struct usb_interface *intf)
+{
+ int i;
+
+ if (uas_is_interface(intf->cur_altsetting))
+ return 0;
+
+ for (i = 0; i < intf->num_altsetting; i++) {
+ struct usb_host_interface *alt = &intf->altsetting[i];
+ if (alt == intf->cur_altsetting)
+ continue;
+ if (uas_is_interface(alt))
+ return usb_set_interface(udev,
+ alt->desc.bInterfaceNumber,
+ alt->desc.bAlternateSetting);
+ }
+
+ return -ENODEV;
+}
+
static void uas_configure_endpoints(struct uas_dev_info *devinfo)
{
struct usb_host_endpoint *eps[4] = { };
@@ -655,13 +683,8 @@
struct uas_dev_info *devinfo;
struct usb_device *udev = interface_to_usbdev(intf);
- if (id->bInterfaceProtocol == 0x50) {
- int ifnum = intf->cur_altsetting->desc.bInterfaceNumber;
-/* XXX: Shouldn't assume that 1 is the alternative we want */
- int ret = usb_set_interface(udev, ifnum, 1);
- if (ret)
- return -ENODEV;
- }
+ if (uas_switch_interface(udev, intf))
+ return -ENODEV;
devinfo = kmalloc(sizeof(struct uas_dev_info), GFP_KERNEL);
if (!devinfo)