Re: [PATCH 0/5] Replace the dmabuf custom test framework with kunit

[Christian König <christian.koenig@amd.com>]

On 3/1/26 19:57, Jason Gunthorpe wrote:
> Using kunit to write tests for new work on dmabuf is coming up:
> 
> https://lore.kernel.org/all/26-v1-b5cab63049c0+191af-dmabuf_map_type_jgg@nvidia.com/
> 
> Replace the custom test framework with kunit to avoid maintaining two
> concurrent test frameworks.

Oh, yes that was on my todo list for like an eternity as well.

No idea when or even if I have time to review that, but feel free to add my Acked-by should that go upstream.

Regards,
Christian.

> 
> The conversion minimizes code changes and uses simple pattern-oriented
> reworks to reduce the chance of breaking any tests. Aside from adding the
> kunit_test_suite() boilerplate, the conversion follows a number of
> patterns:
> 
> Test failures without cleanup. For example:
>    if (!ptr)
>        return -ENOMEM;
> Becomes:
>    KUNIT_ASSERT_NOT_NULL(test, ptr);
> 
> In kunit ASSERT longjumps out of the test.
> 
> Check for error, fail and cleanup:
>    if (err) {
>        pr_err("msg\n");
>        goto cleanup;
>    }
> Becomes:
>    if (err) {
>        KUNIT_FAIL(test, "msg");
>        goto cleanup;
>    }
> Preserve the existing failure messages and cleanup code.
> 
> Cases where the test returns err but prints no message:
>    if (err)
>        goto cleanup;
> Becomes:
>    if (err) {
>        KUNIT_FAIL(test, "msg");
>        goto cleanup;
>    }
> Use KUNIT_FAIL to retain the 'cleanup on err' behavior.
> 
> Overall, the conversion is straightforward.
> 
> The result can be run with kunit.py:
> 
>     $ tools/testing/kunit/kunit.py run --build_dir build_kunit_x86_64 --arch x86_64 --kunitconfig ./drivers/dma-buf/.kunitconfig
>     [20:37:23] Configuring KUnit Kernel ...
>     [20:37:23] Building KUnit Kernel ...
>     Populating config with:
>     $ make ARCH=x86_64 O=build_kunit_x86_64 olddefconfig
>     Building with:
>     $ make all compile_commands.json scripts_gdb ARCH=x86_64 O=build_kunit_x86_64 --jobs=20
>     [20:37:29] Starting KUnit Kernel (1/1)...
>     [20:37:29] ============================================================
>     Running tests with:
>     $ qemu-system-x86_64 -nodefaults -m 1024 -kernel build_kunit_x86_64/arch/x86/boot/bzImage -append 'kunit.enable=1 console=ttyS0 kunit_shutdown=reboot' -no-reboot -nographic -accel kvm -accel hvf -accel tcg -serial stdio -bios qboot.rom
>     [20:37:30] ================ dma-buf-resv (5 subtests) =================
>     [20:37:30] [PASSED] test_sanitycheck
>     [20:37:30] ===================== test_signaling  ======================
>     [20:37:30] [PASSED] kernel
>     [20:37:30] [PASSED] write
>     [20:37:30] [PASSED] read
>     [20:37:30] [PASSED] bookkeep
>     [20:37:30] ================= [PASSED] test_signaling ==================
>     ...
>     [20:37:35] Testing complete. Ran 50 tests: passed: 49, skipped: 1
>     [20:37:35] Elapsed time: 12.635s total, 0.001s configuring, 6.551s building, 6.017s running
> 
> One test that requires two CPUs is skipped since the default VM has a
> single CPU and cannot run the test.
> 
> All other usual ways to run kunit work as well, and all tests are placed
> in a module to provide more options for how they are run.
> 
> AI was used to do the large scale semantic search and replaces described
> above, then everything was hand checked. AI also deduced the issue with
> test_race_signal_callback() in a couple of seconds from the kunit
> crash (!!), again was hand checked though I am not so familiar with this
> test to be fully certain this is the best answer.
> 
> Jason Gunthorpe (5):
>   dma-buf: Change st-dma-resv.c to use kunit
>   dma-buf: Change st-dma-fence.c to use kunit
>   dma-buf: Change st-dma-fence-unwrap.c to use kunit
>   dma-buf: Change st-dma-fence-chain.c to use kunit
>   dma-buf: Remove the old selftest
> 
>  drivers/dma-buf/.kunitconfig          |   2 +
>  drivers/dma-buf/Kconfig               |  11 +-
>  drivers/dma-buf/Makefile              |   5 +-
>  drivers/dma-buf/selftest.c            | 167 ---------------
>  drivers/dma-buf/selftest.h            |  30 ---
>  drivers/dma-buf/selftests.h           |  16 --
>  drivers/dma-buf/st-dma-fence-chain.c  | 217 +++++++++----------
>  drivers/dma-buf/st-dma-fence-unwrap.c | 290 +++++++++++---------------
>  drivers/dma-buf/st-dma-fence.c        | 200 ++++++++----------
>  drivers/dma-buf/st-dma-resv.c         | 145 +++++++------
>  drivers/gpu/drm/i915/Kconfig.debug    |   2 +-
>  11 files changed, 394 insertions(+), 691 deletions(-)
>  create mode 100644 drivers/dma-buf/.kunitconfig
>  delete mode 100644 drivers/dma-buf/selftest.c
>  delete mode 100644 drivers/dma-buf/selftest.h
>  delete mode 100644 drivers/dma-buf/selftests.h
> 
> 
> base-commit: 41dae5ac5e157b0bb260f381eb3df2f4a4610205