patch "parport: fix attempt to write duplicate procfiles" added to char-misc-linus

patch "parport: fix attempt to write duplicate procfiles" added to char-misc-linus

[gregkh]

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

    parport: fix attempt to write duplicate procfiles

to my char-misc git tree which can be found at
    git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/char-misc.git
in the char-misc-linus branch.

The patch will show up in the next release of the linux-next tree
(usually sometime within the next 24 hours during the week.)

The patch will hopefully also be merged in Linus's tree for the
next -rc kernel release.

If you have any questions about this process, please let me know.


>From 03270c6ac6207fc55bbf9d20d195029dca210c79 Mon Sep 17 00:00:00 2001
From: Sudip Mukherjee <sudipm.mukherjee@gmail.com>
Date: Mon, 6 Mar 2017 23:23:42 +0000
Subject: parport: fix attempt to write duplicate procfiles

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.

Fixes: 6fa45a226897 ("parport: add device-model to parport subsystem")
Cc: stable <stable@vger.kernel.org> # v4.4+
Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=1414656
Bugzilla: https://bugs.archlinux.org/task/52322
Tested-by: James Feeney <james@nurealm.net>
Signed-off-by: Sudip Mukherjee <sudip.mukherjee@codethink.co.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/parport/share.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/parport/share.c b/drivers/parport/share.c
index bc090daa850a..5dc53d420ca8 100644
--- a/drivers/parport/share.c
+++ b/drivers/parport/share.c
@@ -939,8 +939,10 @@ parport_register_dev_model(struct parport *port, const char *name,
 	 * 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;
 
-- 
2.12.0