[PATCH 5.4 196/203] s390/qeth: lock the card while changing its hsuid

Greg Kroah-Hartman
2020-01-16T23:27:16Z

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

[ Upstream commit 5b6c7b55cfe26224b0f41b1c226d3534c542787f ]

qeth_l3_dev_hsuid_store() initially checks the card state, but doesn't
take the conf_mutex to ensure that the card stays in this state while
being reconfigured.

Rework the code to take this lock, and drop a redundant state check in a
helper function.

Fixes: b333293058aa ("qeth: add support for af_iucv HiperSockets transport")
Signed-off-by: Julian Wiedmann <jwi@linux.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/s390/net/qeth_core_main.c | 5 ----
drivers/s390/net/qeth_l3_sys.c | 40 +++++++++++++++++++++----------
2 files changed, 28 insertions(+), 17 deletions(-)

diff --git a/drivers/s390/net/qeth_core_main.c b/drivers/s390/net/qeth_core_main.c
index 94e5b6e15ef9..5be4d800e4ba 100644
--- a/drivers/s390/net/qeth_core_main.c
+++ b/drivers/s390/net/qeth_core_main.c
@@ -3378,11 +3378,6 @@ int qeth_configure_cq(struct qeth_card *card, enum qeth_cq cq)
goto out;
}

- if (card->state != CARD_STATE_DOWN) {
- rc = -1;
- goto out;
- }
-
qeth_free_qdio_queues(card);
card->options.cq = cq;
rc = 0;
diff --git a/drivers/s390/net/qeth_l3_sys.c b/drivers/s390/net/qeth_l3_sys.c
index 2f73b33c9347..333fd4619dc6 100644
--- a/drivers/s390/net/qeth_l3_sys.c
+++ b/drivers/s390/net/qeth_l3_sys.c
@@ -270,24 +270,36 @@ static ssize_t qeth_l3_dev_hsuid_store(struct device *dev,
struct device_attribute *attr, const char *buf, size_t count)
{
struct qeth_card *card = dev_get_drvdata(dev);
+ int rc = 0;
char *tmp;
- int rc;

if (!card)
return -EINVAL;

if (!IS_IQD(card))
return -EPERM;
- if (card->state != CARD_STATE_DOWN)
- return -EPERM;
- if (card->options.sniffer)
- return -EPERM;
- if (card->options.cq == QETH_CQ_NOTAVAILABLE)
- return -EPERM;
+
+ mutex_lock(&card->conf_mutex);
+ if (card->state != CARD_STATE_DOWN) {
+ rc = -EPERM;
+ goto out;
+ }
+
+ if (card->options.sniffer) {
+ rc = -EPERM;
+ goto out;
+ }
+
+ if (card->options.cq == QETH_CQ_NOTAVAILABLE) {
+ rc = -EPERM;
+ goto out;
+ }

tmp = strsep((char **)&buf, "\n");
- if (strlen(tmp) > 8)
- return -EINVAL;
+ if (strlen(tmp) > 8) {
+ rc = -EINVAL;
+ goto out;
+ }

if (card->options.hsuid[0])
/* delete old ip address */
@@ -298,11 +310,13 @@ static ssize_t qeth_l3_dev_hsuid_store(struct device *dev,
card->options.hsuid[0] = '\0';
memcpy(card->dev->perm_addr, card->options.hsuid, 9);
qeth_configure_cq(card, QETH_CQ_DISABLED);
- return count;
+ goto out;
}

- if (qeth_configure_cq(card, QETH_CQ_ENABLED))
- return -EPERM;
+ if (qeth_configure_cq(card, QETH_CQ_ENABLED)) {
+ rc = -EPERM;
+ goto out;
+ }

snprintf(card->options.hsuid, sizeof(card->options.hsuid),
"%-8s", tmp);
@@ -311,6 +325,8 @@ static ssize_t qeth_l3_dev_hsuid_store(struct device *dev,

rc = qeth_l3_modify_hsuid(card, true);

+out:
+ mutex_unlock(&card->conf_mutex);
return rc ? rc : count;
}

--
2.20.1