[PATCH net] s390/qeth: Don't call dev_close/dev_open (DOWN/UP)

[PATCH net] s390/qeth: Don't call dev_close/dev_open (DOWN/UP)

[Alexandra Winter]

dev_close() and dev_open() are issued to change the interface state to DOWN
or UP (dev->flags IFF_UP). When the netdev is set DOWN it loses e.g its
Ipv6 addresses and routes. We don't want this in cases of device recovery
(triggered by hardware or software) or when the qeth device is set
offline.

Setting a qeth device offline or online and device recovery actions call
netif_device_detach() and/or netif_device_attach(). That will reset or
set the LOWER_UP indication i.e. change the dev->state Bit
__LINK_STATE_PRESENT. That is enough to e.g. cause bond failovers, and
still preserves the interface settings that are handled by the network
stack.

Don't call dev_open() nor dev_close() from the qeth device driver. Let the
network stack handle this.

Fixes: d4560150cb47 ("s390/qeth: call dev_close() during recovery")
Signed-off-by: Alexandra Winter <wintera@linux.ibm.com>
Reviewed-by: Wenjia Zhang <wenjia@linux.ibm.com>
---
 drivers/s390/net/qeth_core.h      | 1 -
 drivers/s390/net/qeth_core_main.c | 2 --
 drivers/s390/net/qeth_l2_main.c   | 9 ++++++---
 drivers/s390/net/qeth_l3_main.c   | 8 +++++---
 4 files changed, 11 insertions(+), 9 deletions(-)

diff --git a/drivers/s390/net/qeth_core.h b/drivers/s390/net/qeth_core.h
index 1d195429753d..613eab729704 100644
--- a/drivers/s390/net/qeth_core.h
+++ b/drivers/s390/net/qeth_core.h
@@ -716,7 +716,6 @@ struct qeth_card_info {
 	u16 chid;
 	u8 ids_valid:1; /* cssid,iid,chid */
 	u8 dev_addr_is_registered:1;
-	u8 open_when_online:1;
 	u8 promisc_mode:1;
 	u8 use_v1_blkt:1;
 	u8 is_vm_nic:1;
diff --git a/drivers/s390/net/qeth_core_main.c b/drivers/s390/net/qeth_core_main.c
index 1d5b207c2b9e..cd783290bde5 100644
--- a/drivers/s390/net/qeth_core_main.c
+++ b/drivers/s390/net/qeth_core_main.c
@@ -5373,8 +5373,6 @@ int qeth_set_offline(struct qeth_card *card, const struct qeth_discipline *disc,
 	qeth_clear_ipacmd_list(card);
 
 	rtnl_lock();
-	card->info.open_when_online = card->dev->flags & IFF_UP;
-	dev_close(card->dev);
 	netif_device_detach(card->dev);
 	netif_carrier_off(card->dev);
 	rtnl_unlock();
diff --git a/drivers/s390/net/qeth_l2_main.c b/drivers/s390/net/qeth_l2_main.c
index 9f13ed170a43..75910c0bcc2b 100644
--- a/drivers/s390/net/qeth_l2_main.c
+++ b/drivers/s390/net/qeth_l2_main.c
@@ -2388,9 +2388,12 @@ static int qeth_l2_set_online(struct qeth_card *card, bool carrier_ok)
 		qeth_enable_hw_features(dev);
 		qeth_l2_enable_brport_features(card);
 
-		if (card->info.open_when_online) {
-			card->info.open_when_online = 0;
-			dev_open(dev, NULL);
+		if (netif_running(dev)) {
+			local_bh_disable();
+			napi_schedule(&card->napi);
+			/* kick-start the NAPI softirq: */
+			local_bh_enable();
+			qeth_l2_set_rx_mode(dev);
 		}
 		rtnl_unlock();
 	}
diff --git a/drivers/s390/net/qeth_l3_main.c b/drivers/s390/net/qeth_l3_main.c
index af4e60d2917e..b92a32b4b114 100644
--- a/drivers/s390/net/qeth_l3_main.c
+++ b/drivers/s390/net/qeth_l3_main.c
@@ -2018,9 +2018,11 @@ static int qeth_l3_set_online(struct qeth_card *card, bool carrier_ok)
 		netif_device_attach(dev);
 		qeth_enable_hw_features(dev);
 
-		if (card->info.open_when_online) {
-			card->info.open_when_online = 0;
-			dev_open(dev, NULL);
+		if (netif_running(dev)) {
+			local_bh_disable();
+			napi_schedule(&card->napi);
+			/* kick-start the NAPI softirq: */
+			local_bh_enable();
 		}
 		rtnl_unlock();
 	}
-- 
2.39.2

Re: [PATCH net] s390/qeth: Don't call dev_close/dev_open (DOWN/UP)

[patchwork-bot+netdevbpf]

Hello:

This patch was applied to netdev/net.git (main)
by David S. Miller <davem@davemloft.net>:

On Tue,  1 Aug 2023 10:00:16 +0200 you wrote:
> dev_close() and dev_open() are issued to change the interface state to DOWN
> or UP (dev->flags IFF_UP). When the netdev is set DOWN it loses e.g its
> Ipv6 addresses and routes. We don't want this in cases of device recovery
> (triggered by hardware or software) or when the qeth device is set
> offline.
> 
> Setting a qeth device offline or online and device recovery actions call
> netif_device_detach() and/or netif_device_attach(). That will reset or
> set the LOWER_UP indication i.e. change the dev->state Bit
> __LINK_STATE_PRESENT. That is enough to e.g. cause bond failovers, and
> still preserves the interface settings that are handled by the network
> stack.
> 
> [...]

Here is the summary with links:
  - [net] s390/qeth: Don't call dev_close/dev_open (DOWN/UP)
    https://git.kernel.org/netdev/net/c/1cfef80d4c2b

You are awesome, thank you!
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