From: Michael S. Tsirkin Date: Thu, 23 Oct 2014 15:40:30 +0000 (+0300) Subject: KVM: s390 allow virtio_ccw status writes to fail X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=485551366d56c752fcd9aaac0544b9f057226ad6;p=GitHub%2FLineageOS%2FG12%2Fandroid_kernel_amlogic_linux-4.9.git KVM: s390 allow virtio_ccw status writes to fail Gracefully handle failure to write device status. We really should handle other errors as well, but this one is needed for virtio 1.0 compliance. Signed-off-by: Michael S. Tsirkin Reviewed-by: Cornelia Huck --- diff --git a/drivers/s390/kvm/virtio_ccw.c b/drivers/s390/kvm/virtio_ccw.c index 1c21c08f33be..45ab269d70db 100644 --- a/drivers/s390/kvm/virtio_ccw.c +++ b/drivers/s390/kvm/virtio_ccw.c @@ -862,7 +862,9 @@ static u8 virtio_ccw_get_status(struct virtio_device *vdev) static void virtio_ccw_set_status(struct virtio_device *vdev, u8 status) { struct virtio_ccw_device *vcdev = to_vc_device(vdev); + u8 old_status = *vcdev->status; struct ccw1 *ccw; + int ret; ccw = kzalloc(sizeof(*ccw), GFP_DMA | GFP_KERNEL); if (!ccw) @@ -874,7 +876,10 @@ static void virtio_ccw_set_status(struct virtio_device *vdev, u8 status) ccw->flags = 0; ccw->count = sizeof(status); ccw->cda = (__u32)(unsigned long)vcdev->status; - ccw_io_helper(vcdev, ccw, VIRTIO_CCW_DOING_WRITE_STATUS); + ret = ccw_io_helper(vcdev, ccw, VIRTIO_CCW_DOING_WRITE_STATUS); + /* Write failed? We assume status is unchanged. */ + if (ret) + *vcdev->status = old_status; kfree(ccw); }