Revert "USB: gadget core: Issue ->disconnect() callback from usb_gadget_disconnect()"

This reverts commit 0a55187.

The commit triggers the following warning when removing a gadget module
from the kernel:

WARNING: CPU: 0 PID: 462 at drivers/usb/gadget/composite.c:2030 __composite_unbind+0xcc/0xd0 [libcomposite]
Modules linked in: cfg80211 usb_f_acm u_serial g_serial libcomposite atmel_usba_udc(-)
CPU: 0 PID: 462 Comm: rmmod Not tainted 5.4.32-linux4sam-2020.04-rc2 #1
Hardware name: Atmel SAMA5
[<c010da74>] (unwind_backtrace) from [<c010ae84>] (show_stack+0x10/0x14)
[<c010ae84>] (show_stack) from [<c011822c>] (__warn+0xb8/0xd0)
[<c011822c>] (__warn) from [<c01182f4>] (warn_slowpath_fmt+0xb0/0xb8)
[<c01182f4>] (warn_slowpath_fmt) from [<bf00b514>] (__composite_unbind+0xcc/0xd0 [libcomposite])
[<bf00b514>] (__composite_unbind [libcomposite]) from [<c0546988>] (usb_gadget_remove_driver+0x2c/0x54)
[<c0546988>] (usb_gadget_remove_driver) from [<c0546a8c>] (usb_del_gadget_udc+0x58/0xbc)
[<c0546a8c>] (usb_del_gadget_udc) from [<bf000840>] (usba_udc_remove+0x1c/0x24 [atmel_usba_udc])
[<bf000840>] (usba_udc_remove [atmel_usba_udc]) from [<c047c734>] (platform_drv_remove+0x20/0x40)
[<c047c734>] (platform_drv_remove) from [<c047b1bc>] (device_release_driver_internal+0xe8/0x1b8)
[<c047b1bc>] (device_release_driver_internal) from [<c047b2dc>] (driver_detach+0x38/0x60)
[<c047b2dc>] (driver_detach) from [<c0479edc>] (bus_remove_driver+0x4c/0xa0)
[<c0479edc>] (bus_remove_driver) from [<c016fbe0>] (sys_delete_module+0x164/0x204)
[<c016fbe0>] (sys_delete_module) from [<c0101000>] (ret_fast_syscall+0x0/0x54)
Exception stack(0xd5557fa8 to 0xd5557ff0)
7fa0:                   00000000 00000002 0044f184 00000800 f92b1100 beadabbc
7fc0: 00000000 00000002 beadac10 00000081 00000000 beadadfc 0044f148 00000001
7fe0: 0044cf70 beadabc4 004336fb b6e63668

There is no functionity issue related to this warning.

Author: cristibirsan

drivers/usb/gadget/udc/core.c

@@ -701,9 +701,6 @@ EXPORT_SYMBOL_GPL(usb_gadget_connect);
  * as a disconnect (when a VBUS session is active).  Not all systems
  * support software pullup controls.
  *
- * Following a successful disconnect, invoke the ->disconnect() callback
- * for the current gadget driver so that UDC drivers don't need to.
- *
  * Returns zero on success, else negative errno.
  */
 int usb_gadget_disconnect(struct usb_gadget *gadget)
@@ -725,10 +722,8 @@ int usb_gadget_disconnect(struct usb_gadget *gadget)
 	}
 
 	ret = gadget->ops->pullup(gadget, 0);
-	if (!ret) {
+	if (!ret)
 		gadget->connected = 0;
-		gadget->udc->driver->disconnect(gadget);
-	}
 
 out:
 	trace_usb_gadget_disconnect(gadget, ret);
@@ -1297,6 +1292,7 @@ static void usb_gadget_remove_driver(struct usb_udc *udc)
 	kobject_uevent(&udc->dev.kobj, KOBJ_CHANGE);
 
 	usb_gadget_disconnect(udc->gadget);
+	udc->driver->disconnect(udc->gadget);
 	udc->driver->unbind(udc->gadget);
 	usb_gadget_udc_stop(udc);
 
@@ -1486,6 +1482,7 @@ static ssize_t soft_connect_store(struct device *dev,
 		usb_gadget_connect(udc->gadget);
 	} else if (sysfs_streq(buf, "disconnect")) {
 		usb_gadget_disconnect(udc->gadget);
+		udc->driver->disconnect(udc->gadget);
 		usb_gadget_udc_stop(udc);
 	} else {
 		dev_err(dev, "unsupported command '%s'\n", buf);