USB: composite: avoid inconsistent lock state

Avoid the following INFO from lock debugging:

[  369.126112] =================================
[  369.132063] [ INFO: inconsistent lock state ]
[  369.136457] 2.6.28-maemo1 #1
[  369.139387] ---------------------------------
[  369.143782] inconsistent {hardirq-on-W} -> {in-hardirq-W} usage.
[  369.149855] swapper/0 [HC1[1]:SC0[0]:HE0:SE1] takes:
[  369.154890]  (&cdev->lock){+-..}, at: [<bf1979f0>] composite_disconnect+0x1c/0]
[  369.163404] {hardirq-on-W} state was registered at:
[  369.168348]   [<c00788a8>] __lock_acquire+0x5d0/0x7d8
[  369.173506]   [<c0078b14>] lock_acquire+0x64/0x78
[  369.178266]   [<c0263a34>] _spin_lock+0x4c/0x80
[  369.182905]   [<bf19597c>] usb_function_deactivate+0x20/0x70 [g_nokia]
[  369.189527]   [<bf1a0a88>] 0xbf1a0a88
[  369.193281]   [<bf19f450>] 0xbf19f450
[  369.197004]   [<bf19fa3c>] 0xbf19fa3c
[  369.200758]   [<bf1a03a0>] 0xbf1a03a0
[  369.204481]   [<bf19f254>] 0xbf19f254
[  369.208204]   [<bf1a0158>] 0xbf1a0158
[  369.211927]   [<bf1a130c>] 0xbf1a130c
[  369.215650]   [<c01c21f0>] usb_gadget_register_driver+0x12c/0x28c
[  369.221846]   [<bf1a06bc>] 0xbf1a06bc
[  369.225569]   [<bf1a06e8>] 0xbf1a06e8
[  369.229322]   [<c002c2dc>] __exception_text_end+0x64/0x19c
[  369.234877]   [<c0081628>] sys_init_module+0x9c/0x194
[  369.240004]   [<c002c8e0>] ret_fast_syscall+0x0/0x2c
[  369.245039]   [<ffffffff>] 0xffffffff
[  369.248793] irq event stamp: 218356
[  369.252302] hardirqs last  enabled at (218355): [<c003a77c>] omap3_enter_idle+8
[  369.260420] hardirqs last disabled at (218356): [<c0264774>] __irq_svc+0x34/0x0
[  369.267927] softirqs last  enabled at (218348): [<c00585a4>] __do_softirq+0x134
[  369.275892] softirqs last disabled at (218335): [<c005899c>] irq_exit+0x60/0xb0
[  369.283308]
[  369.283308] other info that might help us debug this:
[  369.289930] no locks held by swapper/0.

Cc: David Brownell <david-b@pacbell.net>
Signed-off-by: Felipe Balbi <felipe.balbi@nokia.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/usb/gadget/composite.c

@@ -149,16 +149,17 @@ done:
 int usb_function_deactivate(struct usb_function *function)
 {
 	struct usb_composite_dev	*cdev = function->config->cdev;
+	unsigned long			flags;
 	int				status = 0;
 
-	spin_lock(&cdev->lock);
+	spin_lock_irqsave(&cdev->lock, flags);
 
 	if (cdev->deactivations == 0)
 		status = usb_gadget_disconnect(cdev->gadget);
 	if (status == 0)
 		cdev->deactivations++;
 
-	spin_unlock(&cdev->lock);
+	spin_unlock_irqrestore(&cdev->lock, flags);
 	return status;
 }