linux-kernel - [PATCH 3.2 141/153] s390/qeth: free netdevice when removing a card

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Message-ID: <lsq.1527677562.422910969@decadent.org.uk>
Date:   Wed, 30 May 2018 11:52:42 +0100
From:   Ben Hutchings <ben@...adent.org.uk>
To:     linux-kernel@...r.kernel.org, stable@...r.kernel.org
CC:     akpm@...ux-foundation.org, "David S. Miller" <davem@...emloft.net>,
        "Ursula Braun" <ubraun@...ux.vnet.ibm.com>,
        "Julian Wiedmann" <jwi@...ux.vnet.ibm.com>
Subject: [PATCH 3.2 141/153] s390/qeth: free netdevice when removing a card

3.2.102-rc1 review patch.  If anyone has any objections, please let me know.

------------------

From: Julian Wiedmann <jwi@...ux.vnet.ibm.com>

commit 6be687395b3124f002a653c1a50b3260222b3cd7 upstream.

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.

Fixes: 4a71df50047f ("qeth: new qeth device driver")
Signed-off-by: Julian Wiedmann <jwi@...ux.vnet.ibm.com>
Reviewed-by: Ursula Braun <ubraun@...ux.vnet.ibm.com>
Signed-off-by: David S. Miller <davem@...emloft.net>
[bwh: Backported to 3.2: adjust context]
Signed-off-by: Ben Hutchings <ben@...adent.org.uk>
---
 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(-)

--- a/drivers/s390/net/qeth_core_main.c
+++ b/drivers/s390/net/qeth_core_main.c
@@ -4578,8 +4578,6 @@ 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);
--- a/drivers/s390/net/qeth_l2_main.c
+++ b/drivers/s390/net/qeth_l2_main.c
@@ -897,8 +897,8 @@ 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;
--- a/drivers/s390/net/qeth_l3_main.c
+++ b/drivers/s390/net/qeth_l3_main.c
@@ -3395,8 +3395,8 @@ 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;
 	}