linux-kernel - [PATCH] USB: mos7720: delete parport

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Date:	Mon, 30 May 2016 19:16:33 +0530
From:	Sudip Mukherjee <sudipm.mukherjee@...il.com>
To:	Johan Hovold <johan@...nel.org>,
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Cc:	linux-kernel@...r.kernel.org, linux-usb@...r.kernel.org,
	Sudip Mukherjee <sudipm.mukherjee@...il.com>,
	<stable@...r.kernel.org>
Subject: [PATCH] USB: mos7720: delete parport

parport subsystem has introduced parport_del_port() to delete a port
when it is going away. Without parport_del_port() the registered port
will not be unregistered.
To reproduce and verify the error:
Command to be used is : ls /sys/bus/parport/devices
1) without the device attached there is no output as there is no
registered parport.
2) Attach the device, and the command will show "parport0".
3) Remove the device and the command still shows "parport0".
4) Attach the device again and we get "parport1".

With the patch applied:
1) without the device attached there is no output as there is no
registered parport.
2) Attach the device, and the command will show "parport0".
3) Remove the device and there is no output as "parport0" is now
removed.
4) Attach device again to get "parport0" again.

Cc: <stable@...r.kernel.org> # 4.2+
Signed-off-by: Sudip Mukherjee <sudip.mukherjee@...ethink.co.uk>
---

Tested with MosChip Semiconductor MCS7715 Parallel and serial port
adapter.

Just a minor hitch.
Please perform the above test after removing ppdev and lp modules. They
are having some problems in the release functions and are not releasing
the parport on which they are attached. Separate patches are getting
ready for them.

 drivers/usb/serial/mos7720.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/usb/serial/mos7720.c b/drivers/usb/serial/mos7720.c
index 2eddbe5..5608af4 100644
--- a/drivers/usb/serial/mos7720.c
+++ b/drivers/usb/serial/mos7720.c
@@ -2007,6 +2007,7 @@ static void mos7720_release(struct usb_serial *serial)
 				    urblist_entry)
 			usb_unlink_urb(urbtrack->urb);
 		spin_unlock_irqrestore(&mos_parport->listlock, flags);
+		parport_del_port(mos_parport->pp);

 		kref_put(&mos_parport->ref_count, destroy_mos_parport);
 	}
-- 
1.9.1