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| author | Julian Wiedmann <jwi@linux.ibm.com> | 2020-09-23 10:36:56 +0200 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2020-09-23 12:07:54 -0700 |
| commit | f3380b1edc1dd06d874227570a5fe0fbf50eb607 (patch) | |
| tree | 8df096b76fe9a3caa4e2f196619deac3fcc815bc /drivers/s390 | |
| parent | ab29c480b19465a5174ea8eddfa1bd42becf72c9 (diff) | |
| download | lwn-f3380b1edc1dd06d874227570a5fe0fbf50eb607.tar.gz lwn-f3380b1edc1dd06d874227570a5fe0fbf50eb607.zip | |
s390/qeth: tighten ucast IP locking
The programming of ucast IPs via qeth_l3_modify_ip() is driven
independently from any of our typical locking mechanisms (eg. detaching
the netdevice, or holding the conf_mutex).
So when we inspect the card state to check whether the required cmd IO
should be deferred, there is no protection against concurrent state
changes.
But by slightly re-ordering the teardown sequence, we can rely on the
ip_lock to sufficiently serialize things:
1. when running concurrently to qeth_l3_set_online(), any instance of
qeth_l3_modify_ip() that aquires the ip_lock _after_
qeth_l3_recover_ip() will observe the state as CARD_STATE_SOFTSETUP
and not defer the IO.
2. when running concurrently to qeth_l3_set_offline(), any instance of
qeth_l3_modify_ip() that aquires the ip_lock _after_
qeth_l3_clear_ip_htable() will observe the state as CARD_STATE_DOWN
and defer the IO.
These guarantees in mind, we can now drop the conf_mutex from the
qeth_l3_modify_rxip_vipa() wrapper.
Signed-off-by: Julian Wiedmann <jwi@linux.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'drivers/s390')
| -rw-r--r-- | drivers/s390/net/qeth_l3_main.c | 9 |
1 files changed, 2 insertions, 7 deletions
diff --git a/drivers/s390/net/qeth_l3_main.c b/drivers/s390/net/qeth_l3_main.c index 876a21d451f5..0815b64c9797 100644 --- a/drivers/s390/net/qeth_l3_main.c +++ b/drivers/s390/net/qeth_l3_main.c @@ -591,7 +591,6 @@ int qeth_l3_modify_rxip_vipa(struct qeth_card *card, bool add, const u8 *ip, enum qeth_prot_versions proto) { struct qeth_ipaddr addr; - int rc; qeth_l3_init_ipaddr(&addr, type, proto); if (proto == QETH_PROT_IPV4) @@ -599,11 +598,7 @@ int qeth_l3_modify_rxip_vipa(struct qeth_card *card, bool add, const u8 *ip, else memcpy(&addr.u.a6.addr, ip, 16); - mutex_lock(&card->conf_mutex); - rc = qeth_l3_modify_ip(card, &addr, add); - mutex_unlock(&card->conf_mutex); - - return rc; + return qeth_l3_modify_ip(card, &addr, add); } int qeth_l3_modify_hsuid(struct qeth_card *card, bool add) @@ -1161,9 +1156,9 @@ static void qeth_l3_stop_card(struct qeth_card *card) qeth_diags_trace(card, QETH_DIAGS_CMD_TRACE_DISABLE); if (card->state == CARD_STATE_SOFTSETUP) { + card->state = CARD_STATE_DOWN; qeth_l3_clear_ip_htable(card, 1); qeth_clear_ipacmd_list(card); - card->state = CARD_STATE_DOWN; } qeth_qdio_clear_card(card, 0); |