s390/qeth: detach netdevice while card is offline

When a qeth card is offline, it has no connection to the HW. So none of
our control callbacks can run IO against it, and we can only cache the
input (eg a new MAC address) without providing proper feedback to the
caller. In this context, it seems much more reasonable to simply detach
the netdevice and let the kernel reject any interaction with it.

This also makes all sorts of internal state checks and locking obsolete.

Signed-off-by: Julian Wiedmann <jwi@linux.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 11 insertions, 36 deletions

diff --git a/drivers/s390/net/qeth_l2_main.c b/drivers/s390/net/qeth_l2_main.c
index 295ec94b226f..18dfb1b5e690 100644
--- a/drivers/s390/net/qeth_l2_main.c
+++ b/drivers/s390/net/qeth_l2_main.c
@@ -283,10 +283,7 @@ static int qeth_l2_vlan_rx_add_vid(struct net_device *dev,
 	QETH_CARD_TEXT_(card, 4, "aid:%d", vid);
 	if (!vid)
 		return 0;
-	if (qeth_wait_for_threads(card, QETH_RECOVER_THREAD)) {
-		QETH_CARD_TEXT(card, 3, "aidREC");
-		return 0;
-	}
+
 	id = kmalloc(sizeof(*id), GFP_KERNEL);
 	if (id) {
 		id->vid = vid;
@@ -312,10 +309,7 @@ static int qeth_l2_vlan_rx_kill_vid(struct net_device *dev,
 	int rc = 0;
 
 	QETH_CARD_TEXT_(card, 4, "kid:%d", vid);
-	if (qeth_wait_for_threads(card, QETH_RECOVER_THREAD)) {
-		QETH_CARD_TEXT(card, 3, "kidREC");
-		return 0;
-	}
+
 	mutex_lock(&card->vid_list_mutex);
 	list_for_each_entry(id, &card->vid_list, list) {
 		if (id->vid == vid) {
@@ -496,39 +490,22 @@ static int qeth_l2_set_mac_address(struct net_device *dev, void *p)
 	if (!is_valid_ether_addr(addr->sa_data))
 		return -EADDRNOTAVAIL;
 
-	if (qeth_wait_for_threads(card, QETH_RECOVER_THREAD)) {
-		QETH_CARD_TEXT(card, 3, "setmcREC");
-		return -ERESTARTSYS;
-	}
-
-	/* avoid racing against concurrent state change: */
-	if (!mutex_trylock(&card->conf_mutex))
-		return -EAGAIN;
-
-	if (!qeth_card_hw_is_reachable(card)) {
-		ether_addr_copy(dev->dev_addr, addr->sa_data);
-		goto out_unlock;
-	}
-
 	/* don't register the same address twice */
 	if (ether_addr_equal_64bits(dev->dev_addr, addr->sa_data) &&
 	    (card->info.mac_bits & QETH_LAYER2_MAC_REGISTERED))
-		goto out_unlock;
+		return 0;
 
 	/* add the new address, switch over, drop the old */
 	rc = qeth_l2_send_setmac(card, addr->sa_data);
 	if (rc)
-		goto out_unlock;
+		return rc;
 	ether_addr_copy(old_addr, dev->dev_addr);
 	ether_addr_copy(dev->dev_addr, addr->sa_data);
 
 	if (card->info.mac_bits & QETH_LAYER2_MAC_REGISTERED)
 		qeth_l2_remove_mac(card, old_addr);
 	card->info.mac_bits |= QETH_LAYER2_MAC_REGISTERED;
-
-out_unlock:
-	mutex_unlock(&card->conf_mutex);
-	return rc;
+	return 0;
 }
 
 static void qeth_promisc_to_bridge(struct qeth_card *card)
@@ -603,9 +580,6 @@ static void qeth_l2_set_rx_mode(struct net_device *dev)
 		return;
 
 	QETH_CARD_TEXT(card, 3, "setmulti");
-	if (qeth_threads_running(card, QETH_RECOVER_THREAD) &&
-	    (card->state != CARD_STATE_UP))
-		return;
 
 	spin_lock_bh(&card->mclock);
 
@@ -959,12 +933,13 @@ static int __qeth_l2_set_online(struct ccwgroup_device *gdev, int recovery_mode)
 		else
 			netif_carrier_off(dev);
 
+		netif_device_attach(dev);
 		qeth_enable_hw_features(dev);
 
 		if (recover_flag == CARD_STATE_RECOVER) {
 			if (recovery_mode && !IS_OSN(card)) {
 				if (!qeth_l2_validate_addr(dev)) {
-					qeth_open_internal(dev);
+					qeth_open(dev);
 					qeth_l2_set_rx_mode(dev);
 				}
 			} else {
@@ -1011,7 +986,11 @@ static int __qeth_l2_set_offline(struct ccwgroup_device *cgdev,
 	QETH_DBF_TEXT(SETUP, 3, "setoffl");
 	QETH_DBF_HEX(SETUP, 3, &card, sizeof(void *));
 
+	rtnl_lock();
+	netif_device_detach(card->dev);
 	netif_carrier_off(card->dev);
+	rtnl_unlock();
+
 	recover_flag = card->state;
 	if ((!recovery_mode && card->info.hwtrap) || card->info.hwtrap == 2) {
 		qeth_hw_trap(card, QETH_DIAGS_TRAP_DISARM);
@@ -1052,7 +1031,6 @@ static int qeth_l2_recover(void *ptr)
 	QETH_CARD_TEXT(card, 2, "recover2");
 	dev_warn(&card->gdev->dev,
 		"A recovery process has been started for the device\n");
-	qeth_set_recovery_task(card);
 	__qeth_l2_set_offline(card->gdev, 1);
 	rc = __qeth_l2_set_online(card->gdev, 1);
 	if (!rc)
@@ -1063,7 +1041,6 @@ static int qeth_l2_recover(void *ptr)
 		dev_warn(&card->gdev->dev, "The qeth device driver "
 				"failed to recover an error on the device\n");
 	}
-	qeth_clear_recovery_task(card);
 	qeth_clear_thread_start_bit(card, QETH_RECOVER_THREAD);
 	qeth_clear_thread_running_bit(card, QETH_RECOVER_THREAD);
 	return 0;
@@ -1084,7 +1061,6 @@ static int qeth_l2_pm_suspend(struct ccwgroup_device *gdev)
 {
 	struct qeth_card *card = dev_get_drvdata(&gdev->dev);
 
-	netif_device_detach(card->dev);
 	qeth_set_allowed_threads(card, 0, 1);
 	wait_event(card->wait_q, qeth_threads_running(card, 0xffffffff) == 0);
 	if (gdev->state == CCWGROUP_OFFLINE)
@@ -1114,7 +1090,6 @@ static int qeth_l2_pm_resume(struct ccwgroup_device *gdev)
 		rc = __qeth_l2_set_online(card->gdev, 0);
 
 	qeth_set_allowed_threads(card, 0xffffffff, 0);
-	netif_device_attach(card->dev);
 	if (rc)
 		dev_warn(&card->gdev->dev, "The qeth device driver "
 			"failed to recover an error on the device\n");