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| author | Christian Borntraeger <borntraeger@de.ibm.com> | 2013-01-07 15:51:52 +0100 |
|---|---|---|
| committer | Marcelo Tosatti <mtosatti@redhat.com> | 2013-01-09 18:40:19 -0200 |
| commit | b26ba22bb4f12289f9d5eb878c490e674934a197 (patch) | |
| tree | 0782745449e21009e95e74ff6efbfbf7b14cf1d5 /drivers/s390 | |
| parent | 73fa21ea4fc662a2e8e85f84c4ca3fcb55fa4da2 (diff) | |
| download | linux-stable-b26ba22bb4f12289f9d5eb878c490e674934a197.tar.gz linux-stable-b26ba22bb4f12289f9d5eb878c490e674934a197.tar.bz2 linux-stable-b26ba22bb4f12289f9d5eb878c490e674934a197.zip | |
KVM: s390: Gracefully handle busy conditions on ccw_device_start
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@de.ibm.com>
Signed-off-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Signed-off-by: Marcelo Tosatti <mtosatti@redhat.com>
Diffstat (limited to 'drivers/s390')
| -rw-r--r-- | drivers/s390/kvm/virtio_ccw.c | 13 |
1 files changed, 8 insertions, 5 deletions
diff --git a/drivers/s390/kvm/virtio_ccw.c b/drivers/s390/kvm/virtio_ccw.c index 70419a75d0e0..2edd94af131c 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; } |