vfio/ccw: Remove UUID from s390 debug log

As vfio-ccw devices are created/destroyed, the uuid of the associated
mdevs that are recorded in $S390DBF/vfio_ccw_msg/sprintf get lost.
This is because a pointer to the UUID is stored instead of the UUID
itself, and that memory may have been repurposed if/when the logs are
examined. The result is usually garbage UUID data in the logs, though
there is an outside chance of an oops happening here.

Simply remove the UUID from the traces, as the subchannel number will
provide useful configuration information for problem determination,
and is stored directly into the log instead of a pointer.

As we were the only consumer of mdev_uuid(), remove that too.

Cc: Kirti Wankhede <kwankhede@nvidia.com>
Signed-off-by: Michael Kawano <mkawano@linux.ibm.com>
Fixes: 60e05d1cf0875 ("vfio-ccw: add some logging")
Fixes: b7701dfbf9832 ("vfio-ccw: Register a chp_event callback for vfio-ccw")
[farman: reworded commit message, added Fixes: tags]
Signed-off-by: Eric Farman <farman@linux.ibm.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Reviewed-by: Matthew Rosato <mjrosato@linux.ibm.com>
Reviewed-by: Kirti Wankhede <kwankhede@nvidia.com>
Link: https://lore.kernel.org/r/20220707135737.720765-2-farman@linux.ibm.com
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>

1 files changed, 0 insertions, 5 deletions

diff --git a/include/linux/mdev.h b/include/linux/mdev.h
index bb539794f54a..47ad3b104d9e 100644
--- a/include/linux/mdev.h
+++ b/include/linux/mdev.h
@@ -65,11 +65,6 @@ struct mdev_driver {
 	struct device_driver driver;
 };
 
-static inline const guid_t *mdev_uuid(struct mdev_device *mdev)
-{
-	return &mdev->uuid;
-}
-
 extern struct bus_type mdev_bus_type;
 
 int mdev_register_device(struct device *dev, struct mdev_driver *mdev_driver);