[Bug 2095143] [NEW] Accumulative fixes for build failures against previous stable kernel releases

[Launchpad Bug Tracker]

You have been subscribed to a public bug by You-Sheng Yang (vicamo):

[ Impact ]

backport-iwlwifi-dkms, as a dkms package, is meant to provide
availability of an updated, if not the latest, driver to previously
released kernels. While maintaining such compatibility through all
multiple, branching kernel releases, some of the changes may break the
completeness in some cases.

The current backport-iwlwifi contains numeric problems compatibility to
previous kernel releases, especially when new stable fixes being back
ported to a previous LTS tree. This blocks the desire to deploy a solid,
throughout test against all supported kernels.

The solutions here, as what we have always done, are to fix the adapting
layer in backport-iwlwifi, so that they provide indirect calls the the
APIs available in older kernels.

[ Test Plan ]

1. Install mainline kernel headers of following versions from https://kernel.ubuntu.com/mainline/:
   - v6.5.x
   - v5.17.x
   - v5.12.5
   - v5.10.35
   - v5.7.x
   - v5.4.x >= 5.4.223
   - v5.0.21

2. Install backport-iwlwifi-dkms from plucky-proposed, or a prebuilt one
from https://launchpad.net/~canonical-hwe-
team/+archive/ubuntu/experimental-dkms.

3. The dkms should be compiled automatically with the running kernel. To
compile it against the just installed v6.13 kernels:

```
$ for k in $(dpkg -l| awk '$2 ~ /^linux-headers-.*-generic$/ { print substr($2, length("linux-headers-") + 1); }'|sort -V -r); do sudo dkms install --force backport-iwlwifi/0~93.12955-gite723a6f0 -k $k || break; done
```

[ Where problems could occur ]

The adaption layer was done to provide API compatibility with previously
released kernels. The upstream change may be depending on some
implicitly related fixes, but it doesn't seem to be the case for this
update. What we have here are compile problems.

[ Other Info ]

Only nominate for Plucky because there is no plan to deploy compilation
tests for previous series.

This is being SRU-ed along with bug 2095138. See debdiffs in
https://bugs.launchpad.net/ubuntu/+source/backport-iwlwifi-
dkms/+bug/2095138/comments/10.

========== original bug report ==========

* v6.3-rc1 commit e047c5eaa763 ("kunit: Expose 'static stub' API to
redirect functions") introduced `include/kunit/static_stub.h`, and
defines KUNIT_STATIC_STUB_REDIRECT when CONFIG_KUNIT is enabled, and
KUNIT_TRIGGER_STATIC_STUB otherwise, only when v6.6-rc1 commit
582eb3aeed2d ("kunit: replace KUNIT_TRIGGER_STATIC_STUB maro with
KUNIT_STATIC_STUB_REDIRECT") unified both cases.

* 5.17.15:

v5.16-rc1 commit 8587ca6f34152 ("mm: move kvmalloc-related functions to
slab.h") moved away the function from linux/mm.h to linux/slab.h.

* v5.12.8:

v4.17-rc1 commit 3c8ba0d61d04 ("kernel.h: Retain constant expression
output for max()/min()") adds __is_constexpr to
`include/linux/kernel.h`, and was then moved to `include/linux/minmax.h`
in v5.10-rc1 commit b296a6d53339 ("kernel.h: split out min()/max() et
al. helpers"). However, in v5.13-rc3 commit f747e6667ebb ("linux/bits.h:
fix compilation error with GENMASK"), which was also backported to
v5.12.9 and v5.10.42, __is_constexpr was moved into
`include/linux/const.h`.

Yet all the problem comes to backport-iwlwifi core93 commit 6acf2fe1835b
("Merge remote-tracking branch 'auto/master") that added a copy of
`include/linux/minmax.h` from v6.12-rc1 to the dkms code base, and then
all the dependency and backport efforts related become useless.

* 5.7.19:

v5.8-rc1 commit d9d200bcebc1f ("dma-mapping: add generic helpers for
mapping sgtable objects") added `dma_unmap_sgtable` and more helpers,
and had been backported to v5.4.233. backport-iwlwifi has wrong version
guards about this.

v5.8-rc1 commit 709d6d73c7561 ("scatterlist: add generic wrappers for
iterating over sgtable objects") added `for_each_sgtable_sg` helper
macros, and had been backported to v5.4.233. backport-iwlwifi has wrong
version guards about this.

* v5.0.21

must include linux/kernel.h before linux/overflow.h, and backport-
iwlwifi added a few ref to the latter without the former.

** Affects: backport-iwlwifi-dkms (Ubuntu)
     Importance: Low
     Assignee: You-Sheng Yang (vicamo)
         Status: In Progress

** Affects: backport-iwlwifi-dkms (Ubuntu Plucky)
     Importance: Low
     Assignee: You-Sheng Yang (vicamo)
         Status: In Progress

-- 
Accumulative fixes for build failures against previous stable kernel releases
https://bugs.launchpad.net/bugs/2095143
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