From: Julian Wiedmann <jwi@linux.ibm.com>
Date: Thu, 7 Jan 2021 18:24:41 +0100
Subject: s390/qeth: fix locking for discipline setup / removal
Git-commit: b41b554c1ee75070a14c02a88496b1f231c7eacc
Patch-mainline: v5.11-rc3
References: git-fixes
Due to insufficient locking, qeth_core_set_online() and
qeth_dev_layer2_store() can run in parallel, both attempting to load &
setup the discipline (and stepping on each other toes along the way).
A similar race can also occur between qeth_core_remove_device() and
qeth_dev_layer2_store().
Access to .discipline is meant to be protected by the discipline_mutex,
so add/expand the locking in qeth_core_remove_device() and
qeth_core_set_online().
Adjust the locking in qeth_l*_remove_device() accordingly, as it's now
handled by the callers in a consistent manner.
Based on an initial patch by Ursula Braun.
Fixes: 9dc48ccc68b9 ("qeth: serialize sysfs-triggered device configurations")
Signed-off-by: Julian Wiedmann <jwi@linux.ibm.com>
Reviewed-by: Alexandra Winter <wintera@linux.ibm.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
[ ptesarik: Since SLE15-SP1 still contains pm callbacks, appropriate
locking must be added there. ]
Signed-off-by: Petr Tesarik <ptesarik@suse.com>
---
drivers/s390/net/qeth_core_main.c | 28 ++++++++++++++++++++--------
drivers/s390/net/qeth_l2_main.c | 5 +----
drivers/s390/net/qeth_l3_main.c | 5 +----
3 files changed, 22 insertions(+), 16 deletions(-)
--- a/drivers/s390/net/qeth_core_main.c
+++ b/drivers/s390/net/qeth_core_main.c
@@ -5869,6 +5869,7 @@ static int qeth_core_probe_device(struct
break;
default:
card->info.layer_enforced = true;
+ /* It's so early that we don't need the discipline_mutex yet. */
rc = qeth_core_load_discipline(card, enforced_disc);
if (rc)
goto err_load;
@@ -5904,10 +5905,12 @@ static void qeth_core_remove_device(stru
QETH_DBF_TEXT(SETUP, 2, "removedv");
+ mutex_lock(&card->discipline_mutex);
if (card->discipline) {
card->discipline->remove(gdev);
qeth_core_free_discipline(card);
}
+ mutex_unlock(&card->discipline_mutex);
write_lock_irq(&qeth_core_card_list.rwlock);
list_del(&card->list);
@@ -5923,6 +5926,7 @@ static int qeth_core_set_online(struct c
int rc = 0;
enum qeth_discipline_id def_discipline;
+ mutex_lock(&card->discipline_mutex);
if (!card->discipline) {
if (card->info.type == QETH_CARD_TYPE_IQD)
def_discipline = QETH_DISCIPLINE_LAYER3;
@@ -5938,11 +5942,10 @@ static int qeth_core_set_online(struct c
}
}
- mutex_lock(&card->discipline_mutex);
rc = card->discipline->set_online(gdev);
- mutex_unlock(&card->discipline_mutex);
err:
+ mutex_unlock(&card->discipline_mutex);
return rc;
}
@@ -5972,25 +5975,34 @@ static void qeth_core_shutdown(struct cc
static int qeth_core_freeze(struct ccwgroup_device *gdev)
{
struct qeth_card *card = dev_get_drvdata(&gdev->dev);
+ int rc = 0;
+ mutex_lock(&card->discipline_mutex);
if (card->discipline && card->discipline->freeze)
- return card->discipline->freeze(gdev);
- return 0;
+ rc = card->discipline->freeze(gdev);
+ mutex_unlock(&card->discipline_mutex);
+ return rc;
}
static int qeth_core_thaw(struct ccwgroup_device *gdev)
{
struct qeth_card *card = dev_get_drvdata(&gdev->dev);
+ int rc = 0;
+ mutex_lock(&card->discipline_mutex);
if (card->discipline && card->discipline->thaw)
- return card->discipline->thaw(gdev);
- return 0;
+ rc = card->discipline->thaw(gdev);
+ mutex_unlock(&card->discipline_mutex);
+ return rc;
}
static int qeth_core_restore(struct ccwgroup_device *gdev)
{
struct qeth_card *card = dev_get_drvdata(&gdev->dev);
+ int rc = 0;
+ mutex_lock(&card->discipline_mutex);
if (card->discipline && card->discipline->restore)
- return card->discipline->restore(gdev);
- return 0;
+ rc = card->discipline->restore(gdev);
+ mutex_unlock(&card->discipline_mutex);
+ return rc;
}
static ssize_t group_store(struct device_driver *ddrv, const char *buf,
--- a/drivers/s390/net/qeth_l2_main.c
+++ b/drivers/s390/net/qeth_l2_main.c
@@ -825,11 +825,8 @@ static void qeth_l2_remove_device(struct
qeth_set_allowed_threads(card, 0, 1);
wait_event(card->wait_q, qeth_threads_running(card, 0xffffffff) == 0);
- if (cgdev->state == CCWGROUP_ONLINE) {
- mutex_lock(&card->discipline_mutex);
+ if (cgdev->state == CCWGROUP_ONLINE)
qeth_l2_set_offline(cgdev);
- mutex_unlock(&card->discipline_mutex);
- }
cancel_work_sync(&card->close_dev_work);
if (qeth_netdev_is_registered(card->dev))
--- a/drivers/s390/net/qeth_l3_main.c
+++ b/drivers/s390/net/qeth_l3_main.c
@@ -2475,11 +2475,8 @@ static void qeth_l3_remove_device(struct
qeth_set_allowed_threads(card, 0, 1);
wait_event(card->wait_q, qeth_threads_running(card, 0xffffffff) == 0);
- if (cgdev->state == CCWGROUP_ONLINE) {
- mutex_lock(&card->discipline_mutex);
+ if (cgdev->state == CCWGROUP_ONLINE)
qeth_l3_set_offline(cgdev);
- mutex_unlock(&card->discipline_mutex);
- }
cancel_work_sync(&card->close_dev_work);
if (qeth_netdev_is_registered(card->dev))