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s390/qeth: Fix potential loss of L3-IP@ in case of network issues 

commit 2fe8a236436fe40d8d26a1af8d150fc80f04ee1a upstream.

Symptom:
In case of a bad cable connection (e.g. dirty optics) a fast sequence of
network DOWN-UP-DOWN-UP could happen. UP triggers recovery of the qeth
interface. In case of a second DOWN while recovery is still ongoing, it
can happen that the IP@ of a Layer3 qeth interface is lost and will not
be recovered by the second UP.

Problem:
When registration of IP addresses with Layer 3 qeth devices fails, (e.g.
because of bad address format) the respective IP address is deleted from
its hash-table in the driver. If registration fails because of a ENETDOWN
condition, the address should stay in the hashtable, so a subsequent
recovery can restore it.

3caa4af834 ("qeth: keep ip-address after LAN_OFFLINE failure")
fixes this for registration failures during normal operation, but not
during recovery.

Solution:
Keep L3-IP address in case of ENETDOWN in qeth_l3_recover_ip(). For
consistency with qeth_l3_add_ip() we also keep it in case of EADDRINUSE,
i.e. for some reason the card already/still has this address registered.

Fixes: 4a71df5004 ("qeth: new qeth device driver")
Cc: stable@vger.kernel.org
Signed-off-by: Alexandra Winter <wintera@linux.ibm.com>
Link: https://lore.kernel.org/r/20240206085849.2902775-1-wintera@linux.ibm.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Alexandra Winter 2024-02-06 09:58:49 +01:00 committed by Greg Kroah-Hartman
parent 058fbaf771
commit 5140c4d5f4
1 changed files with 6 additions and 3 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

9
drivers/s390/net/qeth_l3_main.c
View File

@ -254,9 +254,10 @@ static void qeth_l3_clear_ip_htable(struct qeth_card *card, int recover)
if (!recover) {
hash_del(&addr->hnode);
kfree(addr);
continue;
} else {
/* prepare for recovery */
addr->disp_flag = QETH_DISP_ADDR_ADD;
}
addr->disp_flag = QETH_DISP_ADDR_ADD;
}
mutex_unlock(&card->ip_lock);
@ -277,9 +278,11 @@ static void qeth_l3_recover_ip(struct qeth_card *card)
if (addr->disp_flag == QETH_DISP_ADDR_ADD) {
rc = qeth_l3_register_addr_entry(card, addr);
if (!rc) {
if (!rc || rc == -EADDRINUSE || rc == -ENETDOWN) {
/* keep it in the records */
addr->disp_flag = QETH_DISP_ADDR_DO_NOTHING;
} else {
/* bad address */
hash_del(&addr->hnode);
kfree(addr);
}