Patch "parport: fix attempt to write duplicate procfiles" has been added to the 4.9-stable tree

This is a note to let you know that I've just added the patch titled

parport: fix attempt to write duplicate procfiles

to the 4.9-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
parport-fix-attempt-to-write-duplicate-procfiles.patch
and it can be found in the queue-4.9 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Sudip Mukherjee <[email protected]>
Date: Mon, 6 Mar 2017 23:23:42 +0000
Subject: parport: fix attempt to write duplicate procfiles

From: Sudip Mukherjee <[email protected]>

commit 03270c6ac6207fc55bbf9d20d195029dca210c79 upstream.

Usually every parallel port will have a single pardev registered with it. But ppdev driver is an exception. This userspace parallel port driver allows to create multiple parrallel port devices for a single parallel port. And as a result we were having a nice warning like:
"sysctl table check failed:
/dev/parport/parport0/devices/ppdev0/timeslice Sysctl already exists"

Use the same logic as used in parport_register_device() and register the proc files only once for each parallel port.

Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=1414656
Bugzilla: https://bugs.archlinux.org/task/52322

---
 drivers/parport/share.c |    6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

@@ -939,8 +939,10 @@ parport_register_dev_model(struct parpor
 	 * pardevice fields. -arca
 	 */
 	port->ops->init_state(par_dev, par_dev->state);
-	port->proc_device = par_dev;
-	parport_device_proc_register(par_dev);
+	if (!test_and_set_bit(PARPORT_DEVPROC_REGISTERED, &port->devflags)) {
+		port->proc_device = par_dev;
+		parport_device_proc_register(par_dev);
+	}
 
 	return par_dev;
 

Patches currently in stable-queue which might be from [email protected] are

queue-4.9/parport-fix-attempt-to-write-duplicate-procfiles.patch