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>

1 files changed, 7 insertions, 0 deletions

diff --git a/drivers/s390/net/qeth_core.h b/drivers/s390/net/qeth_core.h
index a23875a4fa2b..b54ef12840a2 100644
--- 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];