s390/qeth: fix dangling IO buffers after halt/clear

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>

diff --git a/drivers/s390/net/qeth_core.h b/drivers/s390/net/qeth_core.h
index 7cdebd2..871d447 100644 (file)
--- a/drivers/s390/net/qeth_core.h
+++ b/drivers/s390/net/qeth_core.h
@@ -628,6 +628,7 @@ 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;
 };
@@ -1038,6 +1039,8 @@ 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 6349131..b9a2349 100644 (file)
--- 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;
@@ -1746,6 +1775,8 @@ 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",
@@ -4667,12 +4698,12 @@ 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);
@@ -4711,7 +4742,7 @@ 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;
 }
@@ -4911,9 +4942,9 @@ 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 53fcf66..88f4dc1 100644 (file)
--- a/drivers/s390/net/qeth_core_mpc.h
+++ b/drivers/s390/net/qeth_core_mpc.h
@@ -29,20 +29,6 @@ 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 989935d..9086bc0 100644 (file)
--- a/drivers/s390/net/qeth_l2_main.c
+++ b/drivers/s390/net/qeth_l2_main.c
@@ -845,9 +845,9 @@ 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);
@@ -878,9 +878,9 @@ 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 e7ce73b..2712633 100644 (file)
--- a/drivers/s390/net/qeth_l3_main.c
+++ b/drivers/s390/net/qeth_l3_main.c
@@ -2259,9 +2259,9 @@ 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);
@@ -2297,9 +2297,10 @@ 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)