[PATCH 6.8 060/158] s390/qdio: handle deferred cc1

Greg Kroah-Hartman
2024-04-23T21:41:46Z

From: Peter Oberparleiter <oberpar@linux.ibm.com>

[ Upstream commit 607638faf2ff1cede37458111496e7cc6c977f6f ]

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 2297791c92d0 ("s390/cio: dont unregister subchannel from child-drivers")
commit 5ef1dc40ffa6 ("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: 2297791c92d0 ("s390/cio: dont unregister subchannel from child-drivers")
Reviewed-by: Alexandra Winter <wintera@linux.ibm.com>
Signed-off-by: Peter Oberparleiter <oberpar@linux.ibm.com>
Signed-off-by: Alexander Gordeev <agordeev@linux.ibm.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/s390/cio/qdio_main.c | 28 +++++++++++++++++++++++-----
1 file changed, 23 insertions(+), 5 deletions(-)

diff --git a/drivers/s390/cio/qdio_main.c b/drivers/s390/cio/qdio_main.c
index 9cde55730b65a..ebcb535809882 100644
--- a/drivers/s390/cio/qdio_main.c
+++ b/drivers/s390/cio/qdio_main.c
@@ -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);
}

--
2.43.0