patch "mei: bus: don't clean driver pointer" added to char-misc-linus

[<gregkh@linuxfoundation.org>]

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

    mei: bus: don't clean driver pointer

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 e852c2c251ed9c23ae6e3efebc5ec49adb504207 Mon Sep 17 00:00:00 2001
From: Alexander Usyskin <alexander.usyskin@intel.com>
Date: Mon, 29 Jun 2020 01:53:59 +0300
Subject: mei: bus: don't clean driver pointer

It's not needed to set driver to NULL in mei_cl_device_remove()
which is bus_type remove() handler as this is done anyway
in __device_release_driver().

Actually this is causing an endless loop in driver_detach()
on ubuntu patched kernel, while removing (rmmod) the mei_hdcp module.
The reason list_empty(&drv->p->klist_devices.k_list) is always not-empty.
as the check is always true in  __device_release_driver()
	if (dev->driver != drv)
		return;

The non upstream patch is causing this behavior, titled:
'vfio -- release device lock before userspace requests'

Nevertheless the fix is correct also for the upstream.

Link: https://patchwork.ozlabs.org/project/ubuntu-kernel/patch/20180912085046.3401-2-apw@canonical.com/
Cc: <stable@vger.kernel.org>
Cc: Andy Whitcroft <apw@canonical.com>
Signed-off-by: Alexander Usyskin <alexander.usyskin@intel.com>
Signed-off-by: Tomas Winkler <tomas.winkler@intel.com>
Link: https://lore.kernel.org/r/20200628225359.2185929-1-tomas.winkler@intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/misc/mei/bus.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/drivers/misc/mei/bus.c b/drivers/misc/mei/bus.c
index 8d468e0a950a..f476dbc7252b 100644
--- a/drivers/misc/mei/bus.c
+++ b/drivers/misc/mei/bus.c
@@ -745,9 +745,8 @@ static int mei_cl_device_remove(struct device *dev)
 
 	mei_cl_bus_module_put(cldev);
 	module_put(THIS_MODULE);
-	dev->driver = NULL;
-	return ret;
 
+	return ret;
 }
 
 static ssize_t name_show(struct device *dev, struct device_attribute *a,
-- 
2.27.0