From: Christian Borntraeger <borntraeger@xxxxxxxxxx>
In rare cases a virtio command might try to issue a ccw before a former
ccw was answered with a tsch. This will cause CC=2 (busy). Lets just
retry in that case.
Signed-off-by: Christian Borntraeger <borntraeger@xxxxxxxxxx>
Signed-off-by: Cornelia Huck <cornelia.huck@xxxxxxxxxx>
---
drivers/s390/kvm/virtio_ccw.c | 13 ++++++++-----
1 file changed, 8 insertions(+), 5 deletions(-)
diff --git a/drivers/s390/kvm/virtio_ccw.c b/drivers/s390/kvm/virtio_ccw.c
index 70419a7..2edd94a 100644
--- a/drivers/s390/kvm/virtio_ccw.c
+++ b/drivers/s390/kvm/virtio_ccw.c
@@ -132,11 +132,14 @@ static int ccw_io_helper(struct virtio_ccw_device *vcdev,
unsigned long flags;
int flag = intparm & VIRTIO_CCW_INTPARM_MASK;
- spin_lock_irqsave(get_ccwdev_lock(vcdev->cdev), flags);
- ret = ccw_device_start(vcdev->cdev, ccw, intparm, 0, 0);
- if (!ret)
- vcdev->curr_io |= flag;
- spin_unlock_irqrestore(get_ccwdev_lock(vcdev->cdev), flags);
+ do {
+ spin_lock_irqsave(get_ccwdev_lock(vcdev->cdev), flags);
+ ret = ccw_device_start(vcdev->cdev, ccw, intparm, 0, 0);
+ if (!ret)
+ vcdev->curr_io |= flag;
+ spin_unlock_irqrestore(get_ccwdev_lock(vcdev->cdev), flags);
+ cpu_relax();
+ } while (ret == -EBUSY);
wait_event(vcdev->wait_q, doing_io(vcdev, flag) == 0);
return ret ? ret : vcdev->err;
}
--
1.7.12.4
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