At least since commit 334304ac2bac ("dma-mapping: don't return errors
from dma_set_max_seg_size") setting up device.dma_parms is basically
mandated by the DMA API. As of now Channel (CCW) I/O in general does not
utilize the DMA API, except for virtio. For virtio-ccw however the
common virtio DMA infrastructure is such that most of the DMA stuff
hinges on the virtio parent device, which is a CCW device.
So lets set up the dma_parms pointer for the CCW parent device and hope
for the best!
Signed-off-by: Halil Pasic <pasic@xxxxxxxxxxxxx>
Fixes: 334304ac2bac ("dma-mapping: don't return errors from dma_set_max_seg_size")
Reported-by: "Marc Hartmayer" <mhartmay@xxxxxxxxxxxxx>
Closes: https://bugzilla.linux.ibm.com/show_bug.cgi?id=209131
Reviewed-by: Eric Farman <farman@xxxxxxxxxxxxx>
---
In the long run it may make sense to move dma_parms into struct
ccw_device, since layering-wise it is much cleaner. I decided
to put it in virtio_ccw_device because currently it is only used for
virtio.
---
drivers/s390/virtio/virtio_ccw.c | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/drivers/s390/virtio/virtio_ccw.c b/drivers/s390/virtio/virtio_ccw.c
index 62eca9419ad7..21fa7ac849e5 100644
--- a/drivers/s390/virtio/virtio_ccw.c
+++ b/drivers/s390/virtio/virtio_ccw.c
@@ -58,6 +58,8 @@ struct virtio_ccw_device {
struct virtio_device vdev;
__u8 config[VIRTIO_CCW_CONFIG_SIZE];
struct ccw_device *cdev;
+ /* we make cdev->dev.dma_parms point to this */
+ struct device_dma_parameters dma_parms;
__u32 curr_io;
int err;
unsigned int revision; /* Transport revision */
@@ -1303,6 +1305,7 @@ static int virtio_ccw_offline(struct ccw_device *cdev)
unregister_virtio_device(&vcdev->vdev);
spin_lock_irqsave(get_ccwdev_lock(cdev), flags);
dev_set_drvdata(&cdev->dev, NULL);
+ cdev->dev.dma_parms = NULL;
spin_unlock_irqrestore(get_ccwdev_lock(cdev), flags);
return 0;
}
@@ -1366,6 +1369,7 @@ static int virtio_ccw_online(struct ccw_device *cdev)
}
vcdev->vdev.dev.parent = &cdev->dev;
vcdev->cdev = cdev;
+ cdev->dev.dma_parms = &vcdev->dma_parms;
vcdev->dma_area = ccw_device_dma_zalloc(vcdev->cdev,
sizeof(*vcdev->dma_area),
&vcdev->dma_area_addr);
base-commit: 87d6aab2389e5ce0197d8257d5f8ee965a67c4cd
--
2.43.0
