Patch "s390/qeth: free netdevice when removing a card" has been added to the 4.4-stable tree

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

s390/qeth: free netdevice when removing a card

to the 4.4-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:
s390-qeth-free-netdevice-when-removing-a-card.patch
and it can be found in the queue-4.4 subdirectory.

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

From: Julian Wiedmann <[email protected]>
Date: Tue, 20 Mar 2018 07:59:12 +0100
Subject: s390/qeth: free netdevice when removing a card

From: Julian Wiedmann <[email protected]>

[ Upstream commit 6be687395b3124f002a653c1a50b3260222b3cd7 ]

On removal, a qeth card's netdevice is currently not properly freed because the call chain looks as follows:

qeth_core_remove_device(card)

	lx_remove_device(card)
		unregister_netdev(card->dev)
		card->dev = NULL			!!!
	qeth_core_free_card(card)
		if (card->dev)				!!!
			free_netdev(card->dev)

Fix it by free'ing the netdev straight after unregistering. This also fixes the sysfs-driven layer switch case (qeth_dev_layer2_store()), where the need to free the current netdevice was not considered at all.

Note that free_netdev() takes care of the netif_napi_del() for us too.

---
 drivers/s390/net/qeth_core_main.c |    2 --
 drivers/s390/net/qeth_l2_main.c   |    2 +-
 drivers/s390/net/qeth_l3_main.c   |    2 +-
 3 files changed, 2 insertions(+), 4 deletions(-)

@@ -4969,8 +4969,6 @@ static void qeth_core_free_card(struct q
 	QETH_DBF_HEX(SETUP, 2, &card, sizeof(void *));
 	qeth_clean_channel(&card->read);
 	qeth_clean_channel(&card->write);
-	if (card->dev)
-		free_netdev(card->dev);
 	kfree(card->ip_tbd_list);
 	qeth_free_qdio_buffers(card);
 	unregister_service_level(&card->qeth_service_level);

@@ -1062,8 +1062,8 @@ static void qeth_l2_remove_device(struct
 		qeth_l2_set_offline(cgdev);
 
 	if (card->dev) {
-		netif_napi_del(&card->napi);
 		unregister_netdev(card->dev);
+		free_netdev(card->dev);
 		card->dev = NULL;
 	}
 	return;

@@ -3243,8 +3243,8 @@ static void qeth_l3_remove_device(struct
 		qeth_l3_set_offline(cgdev);
 
 	if (card->dev) {
-		netif_napi_del(&card->napi);
 		unregister_netdev(card->dev);
+		free_netdev(card->dev);
 		card->dev = NULL;
 	}
 

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

queue-4.4/s390-qeth-when-thread-completes-wake-up-all-waiters.patch queue-4.4/s390-qeth-lock-read-device-while-queueing-next-buffer.patch queue-4.4/net-iucv-free-memory-obtained-by-kzalloc.patch queue-4.4/s390-qeth-on-channel-error-reject-further-cmd-requests.patch queue-4.4/s390-qeth-free-netdevice-when-removing-a-card.patch