This is a note to let you know that I've just added the patch titled
s390/virtio_ccw: Fix dma_parm pointer not set up
to the 6.12-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
s390-virtio_ccw-fix-dma_parm-pointer-not-set-up.patch
and it can be found in the queue-6.12 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 60e5c449179c19389de7ea8b6fdfda78e93f94b1
Author: Halil Pasic <pasic@xxxxxxxxxxxxx>
Date: Mon Oct 7 22:10:30 2024 +0200
s390/virtio_ccw: Fix dma_parm pointer not set up
[ Upstream commit 14c7579376279e507e52bf022192b46097a55377 ]
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!
Fixes: 334304ac2bac ("dma-mapping: don't return errors from dma_set_max_seg_size")
Reported-by: Marc Hartmayer <mhartmay@xxxxxxxxxxxxx>
Reviewed-by: Eric Farman <farman@xxxxxxxxxxxxx>
Reviewed-by: Cornelia Huck <cohuck@xxxxxxxxxx>
Tested-by: Marc Hartmayer <mhartmay@xxxxxxxxxxxxx>
Link: https://lore.kernel.org/r/20241007201030.204028-1-pasic@xxxxxxxxxxxxx
Signed-off-by: Halil Pasic <pasic@xxxxxxxxxxxxx>
Signed-off-by: Heiko Carstens <hca@xxxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/s390/virtio/virtio_ccw.c b/drivers/s390/virtio/virtio_ccw.c
index 62eca9419ad76..21fa7ac849e5c 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);
