Commit 607638fa authored by Peter Oberparleiter's avatar Peter Oberparleiter Committed by Alexander Gordeev
Browse files

s390/qdio: handle deferred cc1 



A deferred condition code 1 response indicates that I/O was not started
and should be retried. The current QDIO implementation handles a cc1
response as I/O error, resulting in a failed QDIO setup. This can happen
for example when a path verification request arrives at the same time
as QDIO setup I/O is started.

Fix this by retrying the QDIO setup I/O when a cc1 response is received.

Note that since

commit 2297791c ("s390/cio: dont unregister subchannel from child-drivers")
commit 5ef1dc40 ("s390/cio: fix invalid -EBUSY on ccw_device_start")

deferred cc1 responses are much more likely to occur. See the commit
message of the latter for more background information.

Fixes: 2297791c ("s390/cio: dont unregister subchannel from child-drivers")
Reviewed-by: default avatarAlexandra Winter <wintera@linux.ibm.com>
Signed-off-by: default avatarPeter Oberparleiter <oberpar@linux.ibm.com>
Signed-off-by: default avatarAlexander Gordeev <agordeev@linux.ibm.com>
parent 378ca2d2

drivers/s390/cio/qdio_main.c

+23 −5
Original line number Diff line number Diff line
@@ -722,8 +722,8 @@ static void qdio_handle_activate_check(struct qdio_irq *irq_ptr, 
	lgr_info_log();

}



static void qdio_establish_handle_irq(struct qdio_irq *irq_ptr, int cstat,

				      int dstat)

static int qdio_establish_handle_irq(struct qdio_irq *irq_ptr, int cstat,

				     int dstat, int dcc)

{

	DBF_DEV_EVENT(DBF_INFO, irq_ptr, "qest irq");
@@ -731,15 +731,18 @@ static void qdio_establish_handle_irq(struct qdio_irq *irq_ptr, int cstat, 
		goto error;

	if (dstat & ~(DEV_STAT_DEV_END | DEV_STAT_CHN_END))

		goto error;

	if (dcc == 1)

		return -EAGAIN;

	if (!(dstat & DEV_STAT_DEV_END))

		goto error;

	qdio_set_state(irq_ptr, QDIO_IRQ_STATE_ESTABLISHED);

	return;

	return 0;



error:

	DBF_ERROR("%4x EQ:error", irq_ptr->schid.sch_no);

	DBF_ERROR("ds: %2x cs:%2x", dstat, cstat);

	qdio_set_state(irq_ptr, QDIO_IRQ_STATE_ERR);

	return -EIO;

}



/* qdio interrupt handler */
@@ -748,7 +751,7 @@ void qdio_int_handler(struct ccw_device *cdev, unsigned long intparm, 
{

	struct qdio_irq *irq_ptr = cdev->private->qdio_data;

	struct subchannel_id schid;

	int cstat, dstat;

	int cstat, dstat, rc, dcc;



	if (!intparm || !irq_ptr) {

		ccw_device_get_schid(cdev, &schid);
@@ -768,10 +771,12 @@ void qdio_int_handler(struct ccw_device *cdev, unsigned long intparm, 
	qdio_irq_check_sense(irq_ptr, irb);

	cstat = irb->scsw.cmd.cstat;

	dstat = irb->scsw.cmd.dstat;

	dcc   = scsw_cmd_is_valid_cc(&irb->scsw) ? irb->scsw.cmd.cc : 0;

	rc    = 0;



	switch (irq_ptr->state) {

	case QDIO_IRQ_STATE_INACTIVE:

		qdio_establish_handle_irq(irq_ptr, cstat, dstat);

		rc = qdio_establish_handle_irq(irq_ptr, cstat, dstat, dcc);

		break;

	case QDIO_IRQ_STATE_CLEANUP:

		qdio_set_state(irq_ptr, QDIO_IRQ_STATE_INACTIVE);
@@ -785,12 +790,25 @@ void qdio_int_handler(struct ccw_device *cdev, unsigned long intparm, 
		if (cstat || dstat)

			qdio_handle_activate_check(irq_ptr, intparm, cstat,

						   dstat);

		else if (dcc == 1)

			rc = -EAGAIN;

		break;

	case QDIO_IRQ_STATE_STOPPED:

		break;

	default:

		WARN_ON_ONCE(1);

	}



	if (rc == -EAGAIN) {

		DBF_DEV_EVENT(DBF_INFO, irq_ptr, "qint retry");

		rc = ccw_device_start(cdev, irq_ptr->ccw, intparm, 0, 0);

		if (!rc)

			return;

		DBF_ERROR("%4x RETRY ERR", irq_ptr->schid.sch_no);

		DBF_ERROR("rc:%4x", rc);

		qdio_set_state(irq_ptr, QDIO_IRQ_STATE_ERR);

	}



	wake_up(&cdev->private->wait_q);

}