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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Julian Wiedmann <jwi@linux.vnet.ibm.com>,
        "David S. Miller" <davem@davemloft.net>
Subject: [PATCH 4.15 091/122] s390/qeth: fix IP removal on offline cards
Date:   Wed,  7 Mar 2018 11:38:23 -0800
Message-Id: <20180307191742.558338027@linuxfoundation.org>
In-Reply-To: <20180307191729.190879024@linuxfoundation.org>
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4.15-stable review patch.  If anyone has any objections, please let me know.

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

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


[ Upstream commit 98d823ab1fbdcb13abc25b420f9bb71bade42056 ]

If the HW is not reachable, then none of the IPs in qeth's internal
table has been registered with the HW yet. So when deleting such an IP,
there's no need to stage it for deregistration - just drop it from
the table.

This fixes the "add-delete-add" scenario on an offline card, where the
the second "add" merely increments the IP's use count. But as the IP is
still set to DISP_ADDR_DELETE from the previous "delete" step,
l3_recover_ip() won't register it with the HW when the card goes online.

Fixes: 5f78e29ceebf ("qeth: optimize IP handling in rx_mode callback")
Signed-off-by: Julian Wiedmann <jwi@linux.vnet.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/s390/net/qeth_l3_main.c |   14 +++-----------
 1 file changed, 3 insertions(+), 11 deletions(-)

--- a/drivers/s390/net/qeth_l3_main.c
+++ b/drivers/s390/net/qeth_l3_main.c
@@ -256,12 +256,8 @@ int qeth_l3_delete_ip(struct qeth_card *
 	if (addr->in_progress)
 		return -EINPROGRESS;
 
-	if (!qeth_card_hw_is_reachable(card)) {
-		addr->disp_flag = QETH_DISP_ADDR_DELETE;
-		return 0;
-	}
-
-	rc = qeth_l3_deregister_addr_entry(card, addr);
+	if (qeth_card_hw_is_reachable(card))
+		rc = qeth_l3_deregister_addr_entry(card, addr);
 
 	hash_del(&addr->hnode);
 	kfree(addr);
@@ -404,11 +400,7 @@ static void qeth_l3_recover_ip(struct qe
 	spin_lock_bh(&card->ip_lock);
 
 	hash_for_each_safe(card->ip_htable, i, tmp, addr, hnode) {
-		if (addr->disp_flag == QETH_DISP_ADDR_DELETE) {
-			qeth_l3_deregister_addr_entry(card, addr);
-			hash_del(&addr->hnode);
-			kfree(addr);
-		} else if (addr->disp_flag == QETH_DISP_ADDR_ADD) {
+		if (addr->disp_flag == QETH_DISP_ADDR_ADD) {
 			if (addr->proto == QETH_PROT_IPV4) {
 				addr->in_progress = 1;
 				spin_unlock_bh(&card->ip_lock);