usb: f_mtp: Handle OS descriptors only when bound

Handle OS descriptors and other Vendor defined requests only
when the MTP function is bound. Otherwise MTP responds for
setup requests from Windows Hosts when other gadget drivers are
active and the host ends up loading the wrong driver.

Change-Id: I324d42bd0fab743c7b40d2b119225a6d66781a52
Signed-off-by: Ravi Vembu <raviv@motorola.com>
Moto-CRs-fixed: (CR)
Reviewed-on: https://gerrit.mot.com/946404
SME-Granted: SME Approvals Granted
SLTApproved: Slta Waiver <sltawvr@motorola.com>
Tested-by: Jira Key <jirakey@motorola.com>
Submit-Approved: Jira Key <jirakey@motorola.com>
Reviewed-on: https://gerrit.mot.com/1167321
SLTApproved: Slta Waiver
Tested-by: Jira Key
Reviewed-by: Lu Chai <chailu1@motorola.com>
Reviewed-by: Jianqi Yang <yangj@motorola.com>
Submit-Approved: Jira Key
Reviewed-on: https://gerrit.mot.com/1262838
Reviewed-by: Huosheng Liao <liaohs@motorola.com>
Reviewed-on: https://gerrit.mot.com/1338858
Reviewed-on: https://gerrit.mot.com/1448946
Reviewed-on: https://gerrit.mot.com/1511632
Reviewed-by: Zonghua Liu <a17671@motorola.com>
Reviewed-by: Wang Wang <wangwang1@lenovo.com>

drivers/usb/gadget/function/f_mtp.c

@@ -376,6 +376,7 @@ struct mtp_instance {
 	struct mtp_dev *dev;
 	char mtp_ext_compat_id[16];
 	struct usb_os_desc mtp_os_desc;
+	bool is_bound;
 };
 
 /* temporary variable used between mtp_open() and mtp_gadget_bind() */
@@ -1443,6 +1444,7 @@ mtp_function_bind(struct usb_configuration *c, struct usb_function *f)
 	}
 
 	fi_mtp->func_inst.f = &dev->function;
+	fi_mtp->is_bound = true;
 	mtp_log("%s speed %s: IN/%s, OUT/%s\n",
 		gadget_is_superspeed(c->cdev->gadget) ? "super" :
 		(gadget_is_dualspeed(c->cdev->gadget) ? "dual" : "full"),
@@ -1477,6 +1479,7 @@ mtp_function_unbind(struct usb_configuration *c, struct usb_function *f)
 	kfree(f->os_desc_table);
 	f->os_desc_n = 0;
 	fi_mtp->func_inst.f = NULL;
+	fi_mtp->is_bound = false;
 }
 
 static int mtp_function_set_alt(struct usb_function *f,
@@ -1832,7 +1835,20 @@ static struct usb_function_instance *mtp_alloc_inst(void)
 static int mtp_ctrlreq_configfs(struct usb_function *f,
 				const struct usb_ctrlrequest *ctrl)
 {
-	return mtp_ctrlrequest(f->config->cdev, ctrl);
+	struct mtp_instance *fi_mtp =
+		container_of(f->fi, struct mtp_instance, func_inst);
+
+	if (!f || !f->config) {
+		pr_err("%s: Invalid input for %s function\n",
+			__func__, (f && f->name)? f->name : "unknown");
+
+		return -EINVAL;
+	}
+
+	if (!fi_mtp || (fi_mtp->is_bound == false))
+		return -EOPNOTSUPP;
+	else
+		return mtp_ctrlrequest(f->config->cdev, ctrl);
 }
 
 static void mtp_free(struct usb_function *f)