Commit b1798910fc7f ("drbd: move UAPI headers to include/uapi/linux/")
broke compilation on targets without a hosted libc:

  ./usr/include/linux/drbd.h:18:10: fatal error: sys/types.h: No such
  file or directory

The underlying issue is that there were some constructs left over in
those headers that don't belong in uapi.

Drop the __KERNEL__-gated split in drbd.h. The !__KERNEL__ branch pulls
in <sys/types.h>, <sys/wait.h> and <limits.h> for symbols that the
header does not actually reference; they were carried over from when
this lived in include/linux/.
Replace <asm/types.h> and the entire #ifdef block with the standard
UAPI combo <linux/types.h> + <asm/byteorder.h>, which provides
__u32/__u64/__s32 and __{LITTLE,BIG}_ENDIAN_BITFIELD in both kernel
and userspace contexts.

drbd_limits.h references some enum values and the DRBD_PROT_C define
from drbd.h, but does not include it. Add the missing include while
we're here.

Drop the unprefixed DEBUG_RANGE_CHECK from drbd_limits.h. It has no
in-kernel users and pollutes the userspace namespace.

Switch the drbd.h and drbd_limits.h include guards to the _UAPI_LINUX_*
convention already used by drbd_genl.h.

Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202605101346.V2wwJqv1-lkp@intel.com/
Fixes: b1798910fc7f ("drbd: move UAPI headers to include/uapi/linux/")
Signed-off-by: Christoph Böhmwalder <christoph.boehmwalder@linbit.com>
Link: https://patch.msgid.link/20260513110343.3170338-1-christoph.boehmwalder@linbit.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

Replace the genl_magic multi-include macro system with explicit
serialization and parsing.

The *_gen files were initially produced from a YNL spec via a
customized ynl-gen-c, but the DRBD netlink family is effectively
frozen, so the generator is kept unmodified.
All new functionality will land in a separate, properly-designed
family.
Carry the resulting code as ordinary in-tree source rather than
landing the spec and generator changes that produced it.

The bulk of the changes are mechanical renames to fit the YNL naming
conventions:
  - Handler functions: drbd_adm_* -> drbd_nl_*_doit/dumpit
  - GENL_MAGIC_VERSION -> DRBD_FAMILY_VERSION
  - GENL_MAGIC_FAMILY_HDRSZ -> sizeof(struct drbd_genlmsghdr)
  - drbd_genl_family -> drbd_nl_family
  - Attribute IDs: T_* -> DRBD_A_*

Remove the nested_attr_tb static global buffer and move to a per-call
allocation approach: each deserialization manages its own nested
attribute table. This will be needed anyway when we eventually move
to parallel_ops, and it's actually simpler this way, so make the
move now.

Replace the functionality of the "sensitive" flag: this was only used
by a single field (shared_secret); open-code redaction logic for that
locally.

Also replace the "invariant" flag: this only had a couple of users,
and those basically never change. Hard code the check directly inline.

The genl_family struct itself is defined manually in drbd_nl.c.

Also replace a couple of drbd-specific wrappers (nla_put_u64_0pad,
drbd_nla_find_nested) with standard kernel functions while we're at
it.

Finally, completely remove the genl_magic system; DRBD was its only
user.

Signed-off-by: Christoph Böhmwalder <christoph.boehmwalder@linbit.com>
Acked-by: Jakub Kicinski <kuba@kernel.org>
Link: https://patch.msgid.link/20260506124541.1951772-3-christoph.boehmwalder@linbit.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>

drbd.h and drbd_limits.h contain only type definitions, enums, and
constants shared between kernel and userspace. These should be part of
UAPI.

Split the genl_api header into two: the genlmsghdr and the enums are
UAPI, the rest stays there for now (it will be removed by one of the
next commits in this series).

drbd_config.h is clearly DRBD-internal, so move it there.

Signed-off-by: Christoph Böhmwalder <christoph.boehmwalder@linbit.com>
Acked-by: Jakub Kicinski <kuba@kernel.org>
Link: https://patch.msgid.link/20260506124541.1951772-2-christoph.boehmwalder@linbit.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>