Commit 7359393f authored by Julian Wiedmann's avatar Julian Wiedmann Committed by David S. Miller
Browse files

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: default avatarJulian Wiedmann <jwi@linux.ibm.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 871602b1

drivers/s390/net/qeth_core.h

+7 −0
Original line number Diff line number Diff line
@@ -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];

drivers/s390/net/qeth_core_main.c

+11 −16
Original line number Diff line number Diff line
@@ -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;

	}

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