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Subject[PATCH 5.4 098/102] s390/qeth: fix dangling IO buffers after halt/clear
Date
From: Julian Wiedmann <jwi@linux.ibm.com>

[ Upstream commit f9e50b02a99c3ebbaa30690e8d5be28a5c2624eb ]

The cio layer's intparm logic does not align itself well with how qeth
manages cmd IOs. When an active IO gets terminated via halt/clear, the
corresponding IRQ's intparm does not reflect the cmd buffer but rather
the intparm that was passed to ccw_device_halt() / ccw_device_clear().
This behaviour was recently clarified in
commit b91d9e67e50b ("s390/cio: fix intparm documentation").

As a result, qeth_irq() currently doesn't cancel a cmd that was
terminated via halt/clear. This primarily causes us to leak
card->read_cmd after the qeth device is removed, since our IO path still
holds a refcount for this cmd.

For qeth this means that we need to keep track of which IO is pending on
a device ('active_cmd'), and use this as the intparm when calling
halt/clear. Otherwise qeth_irq() can't match the subsequent IRQ to its
cmd buffer.
Since we now keep track of the _expected_ intparm, we can also detect
any mismatch; this would constitute a bug somewhere in the lower layers.
In this case cancel the active cmd - we effectively "lost" the IRQ and
should not expect any further notification for this IO.

Fixes: 405548959cc7 ("s390/qeth: add support for dynamically allocated cmds")
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.h | 3 ++
drivers/s390/net/qeth_core_main.c | 71 ++++++++++++++++++++++---------
drivers/s390/net/qeth_core_mpc.h | 14 ------
drivers/s390/net/qeth_l2_main.c | 12 +++---
drivers/s390/net/qeth_l3_main.c | 13 +++---
5 files changed, 67 insertions(+), 46 deletions(-)

diff --git a/drivers/s390/net/qeth_core.h b/drivers/s390/net/qeth_core.h
index 65e31df37b1f6..820f2c29376c0 100644
--- a/drivers/s390/net/qeth_core.h
+++ b/drivers/s390/net/qeth_core.h
@@ -620,6 +620,7 @@ struct qeth_ipato {

struct qeth_channel {
struct ccw_device *ccwdev;
+ struct qeth_cmd_buffer *active_cmd;
enum qeth_channel_states state;
atomic_t irq_pending;
};
@@ -1024,6 +1025,8 @@ int qeth_do_run_thread(struct qeth_card *, unsigned long);
void qeth_clear_thread_start_bit(struct qeth_card *, unsigned long);
void qeth_clear_thread_running_bit(struct qeth_card *, unsigned long);
int qeth_core_hardsetup_card(struct qeth_card *card, bool *carrier_ok);
+int qeth_stop_channel(struct qeth_channel *channel);
+
void qeth_print_status_message(struct qeth_card *);
int qeth_init_qdio_queues(struct qeth_card *);
int qeth_send_ipa_cmd(struct qeth_card *, struct qeth_cmd_buffer *,
diff --git a/drivers/s390/net/qeth_core_main.c b/drivers/s390/net/qeth_core_main.c
index 5be4d800e4baa..23852888eb2ca 100644
--- a/drivers/s390/net/qeth_core_main.c
+++ b/drivers/s390/net/qeth_core_main.c
@@ -515,7 +515,9 @@ static int __qeth_issue_next_read(struct qeth_card *card)

QETH_CARD_TEXT(card, 6, "noirqpnd");
rc = ccw_device_start(channel->ccwdev, ccw, (addr_t) iob, 0, 0);
- if (rc) {
+ if (!rc) {
+ channel->active_cmd = iob;
+ } else {
QETH_DBF_MESSAGE(2, "error %i on device %x when starting next read ccw!\n",
rc, CARD_DEVID(card));
atomic_set(&channel->irq_pending, 0);
@@ -986,8 +988,21 @@ static void qeth_irq(struct ccw_device *cdev, unsigned long intparm,
QETH_CARD_TEXT(card, 5, "data");
}

- if (qeth_intparm_is_iob(intparm))
- iob = (struct qeth_cmd_buffer *) __va((addr_t)intparm);
+ if (intparm == 0) {
+ QETH_CARD_TEXT(card, 5, "irqunsol");
+ } else if ((addr_t)intparm != (addr_t)channel->active_cmd) {
+ QETH_CARD_TEXT(card, 5, "irqunexp");
+
+ dev_err(&cdev->dev,
+ "Received IRQ with intparm %lx, expected %px\n",
+ intparm, channel->active_cmd);
+ if (channel->active_cmd)
+ qeth_cancel_cmd(channel->active_cmd, -EIO);
+ } else {
+ iob = (struct qeth_cmd_buffer *) (addr_t)intparm;
+ }
+
+ channel->active_cmd = NULL;

rc = qeth_check_irb_error(card, cdev, irb);
if (rc) {
@@ -1007,15 +1022,10 @@ static void qeth_irq(struct ccw_device *cdev, unsigned long intparm,
if (irb->scsw.cmd.fctl & (SCSW_FCTL_HALT_FUNC))
channel->state = CH_STATE_HALTED;

- if (intparm == QETH_CLEAR_CHANNEL_PARM) {
- QETH_CARD_TEXT(card, 6, "clrchpar");
- /* we don't have to handle this further */
- intparm = 0;
- }
- if (intparm == QETH_HALT_CHANNEL_PARM) {
- QETH_CARD_TEXT(card, 6, "hltchpar");
- /* we don't have to handle this further */
- intparm = 0;
+ if (iob && (irb->scsw.cmd.fctl & (SCSW_FCTL_CLEAR_FUNC |
+ SCSW_FCTL_HALT_FUNC))) {
+ qeth_cancel_cmd(iob, -ECANCELED);
+ iob = NULL;
}

cstat = irb->scsw.cmd.cstat;
@@ -1408,7 +1418,7 @@ static int qeth_clear_channel(struct qeth_card *card,

QETH_CARD_TEXT(card, 3, "clearch");
spin_lock_irq(get_ccwdev_lock(channel->ccwdev));
- rc = ccw_device_clear(channel->ccwdev, QETH_CLEAR_CHANNEL_PARM);
+ rc = ccw_device_clear(channel->ccwdev, (addr_t)channel->active_cmd);
spin_unlock_irq(get_ccwdev_lock(channel->ccwdev));

if (rc)
@@ -1430,7 +1440,7 @@ static int qeth_halt_channel(struct qeth_card *card,

QETH_CARD_TEXT(card, 3, "haltch");
spin_lock_irq(get_ccwdev_lock(channel->ccwdev));
- rc = ccw_device_halt(channel->ccwdev, QETH_HALT_CHANNEL_PARM);
+ rc = ccw_device_halt(channel->ccwdev, (addr_t)channel->active_cmd);
spin_unlock_irq(get_ccwdev_lock(channel->ccwdev));

if (rc)
@@ -1444,6 +1454,25 @@ static int qeth_halt_channel(struct qeth_card *card,
return 0;
}

+int qeth_stop_channel(struct qeth_channel *channel)
+{
+ struct ccw_device *cdev = channel->ccwdev;
+ int rc;
+
+ rc = ccw_device_set_offline(cdev);
+
+ spin_lock_irq(get_ccwdev_lock(cdev));
+ if (channel->active_cmd) {
+ dev_err(&cdev->dev, "Stopped channel while cmd %px was still active\n",
+ channel->active_cmd);
+ channel->active_cmd = NULL;
+ }
+ spin_unlock_irq(get_ccwdev_lock(cdev));
+
+ return rc;
+}
+EXPORT_SYMBOL_GPL(qeth_stop_channel);
+
static int qeth_halt_channels(struct qeth_card *card)
{
int rc1 = 0, rc2 = 0, rc3 = 0;
@@ -1747,6 +1776,8 @@ static int qeth_send_control_data(struct qeth_card *card,
spin_lock_irq(get_ccwdev_lock(channel->ccwdev));
rc = ccw_device_start_timeout(channel->ccwdev, __ccw_from_cmd(iob),
(addr_t) iob, 0, 0, timeout);
+ if (!rc)
+ channel->active_cmd = iob;
spin_unlock_irq(get_ccwdev_lock(channel->ccwdev));
if (rc) {
QETH_DBF_MESSAGE(2, "qeth_send_control_data on device %x: ccw_device_start rc = %i\n",
@@ -4625,12 +4656,12 @@ EXPORT_SYMBOL_GPL(qeth_vm_request_mac);

static void qeth_determine_capabilities(struct qeth_card *card)
{
+ struct qeth_channel *channel = &card->data;
+ struct ccw_device *ddev = channel->ccwdev;
int rc;
- struct ccw_device *ddev;
int ddev_offline = 0;

QETH_CARD_TEXT(card, 2, "detcapab");
- ddev = CARD_DDEV(card);
if (!ddev->online) {
ddev_offline = 1;
rc = ccw_device_set_online(ddev);
@@ -4669,7 +4700,7 @@ static void qeth_determine_capabilities(struct qeth_card *card)

out_offline:
if (ddev_offline == 1)
- ccw_device_set_offline(ddev);
+ qeth_stop_channel(channel);
out:
return;
}
@@ -4870,9 +4901,9 @@ retry:
QETH_DBF_MESSAGE(2, "Retrying to do IDX activates on device %x.\n",
CARD_DEVID(card));
rc = qeth_qdio_clear_card(card, !IS_IQD(card));
- ccw_device_set_offline(CARD_DDEV(card));
- ccw_device_set_offline(CARD_WDEV(card));
- ccw_device_set_offline(CARD_RDEV(card));
+ qeth_stop_channel(&card->data);
+ qeth_stop_channel(&card->write);
+ qeth_stop_channel(&card->read);
qdio_free(CARD_DDEV(card));
rc = ccw_device_set_online(CARD_RDEV(card));
if (rc)
diff --git a/drivers/s390/net/qeth_core_mpc.h b/drivers/s390/net/qeth_core_mpc.h
index b7c17b5c823b2..65038539b324b 100644
--- a/drivers/s390/net/qeth_core_mpc.h
+++ b/drivers/s390/net/qeth_core_mpc.h
@@ -28,20 +28,6 @@ extern unsigned char IPA_PDU_HEADER[];
#define QETH_TIMEOUT (10 * HZ)
#define QETH_IPA_TIMEOUT (45 * HZ)

-#define QETH_CLEAR_CHANNEL_PARM -10
-#define QETH_HALT_CHANNEL_PARM -11
-
-static inline bool qeth_intparm_is_iob(unsigned long intparm)
-{
- switch (intparm) {
- case QETH_CLEAR_CHANNEL_PARM:
- case QETH_HALT_CHANNEL_PARM:
- case 0:
- return false;
- }
- return true;
-}
-
/*****************************************************************************/
/* IP Assist related definitions */
/*****************************************************************************/
diff --git a/drivers/s390/net/qeth_l2_main.c b/drivers/s390/net/qeth_l2_main.c
index 11e3292c0adfc..59e220749ad1f 100644
--- a/drivers/s390/net/qeth_l2_main.c
+++ b/drivers/s390/net/qeth_l2_main.c
@@ -877,9 +877,9 @@ static int qeth_l2_set_online(struct ccwgroup_device *gdev)

out_remove:
qeth_l2_stop_card(card);
- ccw_device_set_offline(CARD_DDEV(card));
- ccw_device_set_offline(CARD_WDEV(card));
- ccw_device_set_offline(CARD_RDEV(card));
+ qeth_stop_channel(&card->data);
+ qeth_stop_channel(&card->write);
+ qeth_stop_channel(&card->read);
qdio_free(CARD_DDEV(card));

mutex_unlock(&card->conf_mutex);
@@ -910,9 +910,9 @@ static int __qeth_l2_set_offline(struct ccwgroup_device *cgdev,
rtnl_unlock();

qeth_l2_stop_card(card);
- rc = ccw_device_set_offline(CARD_DDEV(card));
- rc2 = ccw_device_set_offline(CARD_WDEV(card));
- rc3 = ccw_device_set_offline(CARD_RDEV(card));
+ rc = qeth_stop_channel(&card->data);
+ rc2 = qeth_stop_channel(&card->write);
+ rc3 = qeth_stop_channel(&card->read);
if (!rc)
rc = (rc2) ? rc2 : rc3;
if (rc)
diff --git a/drivers/s390/net/qeth_l3_main.c b/drivers/s390/net/qeth_l3_main.c
index 5152970a9aa4b..a1c23e998f977 100644
--- a/drivers/s390/net/qeth_l3_main.c
+++ b/drivers/s390/net/qeth_l3_main.c
@@ -2383,9 +2383,9 @@ static int qeth_l3_set_online(struct ccwgroup_device *gdev)
return 0;
out_remove:
qeth_l3_stop_card(card);
- ccw_device_set_offline(CARD_DDEV(card));
- ccw_device_set_offline(CARD_WDEV(card));
- ccw_device_set_offline(CARD_RDEV(card));
+ qeth_stop_channel(&card->data);
+ qeth_stop_channel(&card->write);
+ qeth_stop_channel(&card->read);
qdio_free(CARD_DDEV(card));

mutex_unlock(&card->conf_mutex);
@@ -2421,9 +2421,10 @@ static int __qeth_l3_set_offline(struct ccwgroup_device *cgdev,
call_netdevice_notifiers(NETDEV_REBOOT, card->dev);
rtnl_unlock();
}
- rc = ccw_device_set_offline(CARD_DDEV(card));
- rc2 = ccw_device_set_offline(CARD_WDEV(card));
- rc3 = ccw_device_set_offline(CARD_RDEV(card));
+
+ rc = qeth_stop_channel(&card->data);
+ rc2 = qeth_stop_channel(&card->write);
+ rc3 = qeth_stop_channel(&card->read);
if (!rc)
rc = (rc2) ? rc2 : rc3;
if (rc)
--
2.20.1


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