[PATCH 4.18 083/235] s390/qeth: reset layer2 attribute on layer switch

From: Greg Kroah-Hartman
Date: Mon Sep 24 2018 - 08:34:30 EST

4.18-stable review patch. If anyone has any objections, please let me know.


From: Julian Wiedmann <jwi@xxxxxxxxxxxxx>

[ Upstream commit 70551dc46ffa3555a0b5f3545b0cd87ab67fd002 ]

After the subdriver's remove() routine has completed, the card's layer
mode is undetermined again. Reflect this in the layer2 field.

If qeth_dev_layer2_store() hits an error after remove() was called, the
card _always_ requires a setup(), even if the previous layer mode is
requested again.
But qeth_dev_layer2_store() bails out early if the requested layer mode
still matches the current one. So unless we reset the layer2 field,
re-probing the card back to its previous mode is currently not possible.

Signed-off-by: Julian Wiedmann <jwi@xxxxxxxxxxxxx>
Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <alexander.levin@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
drivers/s390/net/qeth_core_sys.c | 1 +
1 file changed, 1 insertion(+)

--- a/drivers/s390/net/qeth_core_sys.c
+++ b/drivers/s390/net/qeth_core_sys.c
@@ -426,6 +426,7 @@ static ssize_t qeth_dev_layer2_store(str
if (card->discipline) {
+ card->options.layer2 = -1;

rc = qeth_core_load_discipline(card, newdis);