kho: disallow wide keys in radix tree

The KHO radix tree was designed to track preserved pages. So it does not
provide the capability to track any 64-bit key. Instead, it limits the
key width to how much it needs for tracking PFNs and their orders.
Limiting the width reduces the number of levels in the tree.

KHO is not expected to be the only user of the radix tree. With the API
generalized to allow other users, now it is possible to add any key to
the tree.

Check the key width at kho_radix_add_key(), and error out if it exceeds
what the tree can handle. Do this instead of increasing the tree depth
since right now there are no users that need to use wider keys, so this
avoids memory overhead and ABI breakage.

Signed-off-by: Pratyush Yadav (Google) <pratyush@kernel.org>
Link: https://patch.msgid.link/20260801084833.1897543-4-pratyush@kernel.org
Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org>

0 files changed, 0 insertions, 0 deletions