s390/qeth: wake up all waiters from qeth_irq()

card->wait_q is shared by different users, for different wake-up
conditions. qeth_irq() can potentially trigger multiple of these
conditions:
1) A change to channel->irq_pending, which qeth_send_control_data() is
   waiting for.
2) A change to card->state, which qeth_clear_channel() and
   qeth_halt_channel() are waiting for.

As qeth_irq() does only a single wake_up(), we might miss to wake up
a second eligible waiter. Luckily all waiters are guarded with a
timeout, so this situation should recover on its own eventually.

To make things work robustly, add an additional wake_up() for changes
to channel->state. And extract a helper that updates
channel->irq_pending along with the needed wake_up().

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 a23875a..b54ef12 100644 (file)
--- a/drivers/s390/net/qeth_core.h
+++ b/drivers/s390/net/qeth_core.h
@@ -862,6 +862,13 @@ static inline bool qeth_card_hw_is_reachable(struct qeth_card *card)
        return card->state == CARD_STATE_SOFTSETUP;
 }
 
+static inline void qeth_unlock_channel(struct qeth_card *card,
+                                      struct qeth_channel *channel)
+{
+       atomic_set(&channel->irq_pending, 0);
+       wake_up(&card->wait_q);
+}
+
 struct qeth_trap_id {
        __u16 lparnr;
        char vmname[8];

diff --git a/drivers/s390/net/qeth_core_main.c b/drivers/s390/net/qeth_core_main.c
index 3d23748..38f3ed7 100644 (file)
--- a/drivers/s390/net/qeth_core_main.c
+++ b/drivers/s390/net/qeth_core_main.c
@@ -520,11 +520,10 @@ static int __qeth_issue_next_read(struct qeth_card *card)
        } 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);
+               qeth_unlock_channel(card, channel);
                qeth_put_cmd(iob);
                card->read_or_write_problem = 1;
                qeth_schedule_recovery(card);
-               wake_up(&card->wait_q);
        }
        return rc;
 }
@@ -1001,24 +1000,25 @@ static void qeth_irq(struct ccw_device *cdev, unsigned long intparm,
        }
 
        channel->active_cmd = NULL;
+       qeth_unlock_channel(card, channel);
 
        rc = qeth_check_irb_error(card, cdev, irb);
        if (rc) {
                /* IO was terminated, free its resources. */
                if (iob)
                        qeth_cancel_cmd(iob, rc);
-               atomic_set(&channel->irq_pending, 0);
-               wake_up(&card->wait_q);
                return;
        }
 
-       atomic_set(&channel->irq_pending, 0);
-
-       if (irb->scsw.cmd.fctl & (SCSW_FCTL_CLEAR_FUNC))
+       if (irb->scsw.cmd.fctl & SCSW_FCTL_CLEAR_FUNC) {
                channel->state = CH_STATE_STOPPED;
+               wake_up(&card->wait_q);
+       }
 
-       if (irb->scsw.cmd.fctl & (SCSW_FCTL_HALT_FUNC))
+       if (irb->scsw.cmd.fctl & SCSW_FCTL_HALT_FUNC) {
                channel->state = CH_STATE_HALTED;
+               wake_up(&card->wait_q);
+       }
 
        if (iob && (irb->scsw.cmd.fctl & (SCSW_FCTL_CLEAR_FUNC |
                                          SCSW_FCTL_HALT_FUNC))) {
@@ -1052,7 +1052,7 @@ static void qeth_irq(struct ccw_device *cdev, unsigned long intparm,
                                qeth_cancel_cmd(iob, rc);
                        qeth_clear_ipacmd_list(card);
                        qeth_schedule_recovery(card);
-                       goto out;
+                       return;
                }
        }
 
@@ -1060,16 +1060,12 @@ static void qeth_irq(struct ccw_device *cdev, unsigned long intparm,
                /* sanity check: */
                if (irb->scsw.cmd.count > iob->length) {
                        qeth_cancel_cmd(iob, -EIO);
-                       goto out;
+                       return;
                }
                if (iob->callback)
                        iob->callback(card, iob,
                                      iob->length - irb->scsw.cmd.count);
        }
-
-out:
-       wake_up(&card->wait_q);
-       return;
 }
 
 static void qeth_notify_skbs(struct qeth_qdio_out_q *q,
@@ -1780,8 +1776,7 @@ static int qeth_send_control_data(struct qeth_card *card,
                QETH_CARD_TEXT_(card, 2, " err%d", rc);
                qeth_dequeue_cmd(card, iob);
                qeth_put_cmd(iob);
-               atomic_set(&channel->irq_pending, 0);
-               wake_up(&card->wait_q);
+               qeth_unlock_channel(card, channel);
                goto out;
        }