netdev - [PATCH net] mctp: Remove device type check at unregister

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Date:   Wed, 14 Dec 2022 14:10:44 +0800
From:   Matt Johnston <matt@...econstruct.com.au>
To:     netdev@...r.kernel.org
Cc:     pabeni@...hat.com, kuba@...nel.org, edumazet@...gle.com,
        davem@...emloft.net, jk@...econstruct.com.au
Subject: [PATCH net] mctp: Remove device type check at unregister

The check could be incorrectly triggered if a netdev
changes its type after register. That is possible for a tun device
using TUNSETLINK ioctl, resulting in mctp unregister failing
and the netdev unregister waiting forever.

This was encountered by https://github.com/openthread/openthread/issues/8523

The check is not required, it was added in an attempt to track down mctp_ptr
being set unexpectedly, which should not happen in normal operation.

Fixes: 7b1871af75f3 ("mctp: Warn if pointer is set for a wrong dev type")
Signed-off-by: Matt Johnston <matt@...econstruct.com.au>
---
 net/mctp/device.c | 6 ------
 1 file changed, 6 deletions(-)

diff --git a/net/mctp/device.c b/net/mctp/device.c
index 99a3bda8852f..dec730b5fe7e 100644
--- a/net/mctp/device.c
+++ b/net/mctp/device.c
@@ -429,12 +429,6 @@ static void mctp_unregister(struct net_device *dev)
 	struct mctp_dev *mdev;
 
 	mdev = mctp_dev_get_rtnl(dev);
-	if (mdev && !mctp_known(dev)) {
-		// Sanity check, should match what was set in mctp_register
-		netdev_warn(dev, "%s: BUG mctp_ptr set for unknown type %d",
-			    __func__, dev->type);
-		return;
-	}
 	if (!mdev)
 		return;
 
-- 
2.37.2