fs: port mnt_idmap_{get,put}() to const mnt_idmap

struct mnt_idmap is immutable once alloc_mnt_idmap() has set it up. The
only thing that changes afterwards is the reference count. Model
mnt_idmap_{get,put}() after struct cred's reference count handling and
take a const pointer.

This model is forced upon us because ceph stores the idmapping in mds
requests and need to be able to take and put references.

mnt_idmap_get() keeps returning a non-const pointer for now because
struct vfsmount still stores a non-const pointer. We can only change
that at the end of the series once every user of mnt_idmap() has been
ported.

Link: https://patch.msgid.link/20260901-work-idmap-const-v1-2-54ccd48e100b@kernel.org
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Seth Forshee <sforshee@kernel.org>
Signed-off-by: Christian Brauner (Amutable) <brauner@kernel.org>

0 files changed, 0 insertions, 0 deletions