drm/i915/selftests: add local workqueue for SW fence selftest

Instead of using a global workqueue for the SW fence selftest,
allocate a separate one temporarily only while running the test.

Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Cc: Jani Nikula <jani.nikula@intel.com>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/313f4a713053c2b4896ced5b0e9ff456eb85fe57.1686231190.git.jani.nikula@intel.com

drm/i915: Drop stealing of bits from i915_sw_fence function pointer

Rather than stealing bits from i915_sw_fence function pointer use
separate fields for function pointer and flags. If using two different
fields, the 4 byte alignment for the i915_sw_fence function pointer can
also be dropped.

v2:
(CI)
- Set new function field rather than flags in __i915_sw_fence_init
v3:
(Tvrtko)
- Remove BUG_ON(!fence->flags) in reinit as that will now blow up
- Only define fence->flags if CONFIG_DRM_I915_SW_FENCE_CHECK_DAG is
defined
v4:
- Rebase, resend for CI

Signed-off-by: Matthew Brost <matthew.brost@intel.com>
Acked-by: Jani Nikula <jani.nikula@intel.com>
Reviewed-by: Alan Previn <alan.previn.teres.alexis@intel.com>
Signed-off-by: John Harrison <John.C.Harrison@Intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20211116194929.10211-1-matthew.brost@intel.com

drm/i915/selftests: Disable preemption while setting up fence-timers

The impossible happens and a future fence expired while we were still
initialising. The probable cause is that the test was preempted and we
lost our scheduler cpu slice. Disable preemption during this test to
rule out preemption as a source of timer disruption.

References: https://bugs.freedesktop.org/show_bug.cgi?id=110039
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190313205944.5768-1-chris@chris-wilson.co.uk

drm/i915: Remove unecessary dma_fence_ops

dma_fence_default_wait is the default now, same for the trivial
enable_signaling implementation.

v2: Also remove the relase hook, dma_fence_free is the default.

Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Cc: Colin Ian King <colin.king@canonical.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Mika Kuoppala <mika.kuoppala@intel.com>
Cc: intel-gfx@lists.freedesktop.org
Link: https://patchwork.freedesktop.org/patch/msgid/20180704092909.6599-2-daniel.vetter@ffwll.ch

drm/i915/selftests: Wait for the dma-fence timeout

When testing that the timeout fired, we need to be sure we have waited
just long enough for the timeout to have occurred and for the softirq
(on another cpu) to have completed. Sleeping for an arbitrary amount is
prone to error, so wait for the timeout instead and complain if it was
too late.

v2: Use wait_event_timeout to provide an upper bound
v3: Fix inverted check for wait_event_timeout timing out
v4: Restore the check that the fences aren't signalled too early, by
inspecting them before the expected timeout.

References: https://bugs.freedesktop.org/show_bug.cgi?id=104670
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180117135713.2324-1-chris@chris-wilson.co.uk

drm/i915/selftests: Test i915_sw_fence/dma_fence interop

Check that we can successfully wait upon a dma_fence using the
i915_sw_fence, including the optional timeout mechanism.

v2: Account for the rounding up of the timeout to the next second.
Unfortunately, the minimum delay is then 1 second.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20180115204348.8480-1-chris@chris-wilson.co.uk
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>

drm/i915/selftests: Wrap a timer into a i915_sw_fence

For some selftests, we want to issue requests but delay them going to
hardware. Furthermore, we don't want those requests to block
indefinitely (or else we may hang the driver and block testing) so we
want to employ a timeout. So naturally we want a fence that is
automatically signaled by a timer.

v2: Add kselftests.
v3: Limit the API available to selftests; there isn't an overwhelming
reason to export it universally.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20171012125726.14736-2-chris@chris-wilson.co.uk
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com>

drm/i915: Check for allocation failure

The memory allocation for C is not being null checked and hence we
could end up with a null pointer dereference. Fix this with a null
pointer check. (I really should have noticed this when I was fixing an
earlier issue.)

Detected by CoverityScan, CID#1436406 ("Dereference null return")

Fixes: 47624cc3301b60 ("drm/i915: Import the kfence selftests for i915_sw_fence")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20170519175617.7036-1-colin.king@canonical.com
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>

drm/i915: Check C for null pointer rather than B

There are two occasions where pointer B is being check for a NULL
when it should be pointer C instead. Fix these.

Detected by CoverityScan, CID#1436348,1436349 ("Logically Dead Code")

Fixes: 47624cc3301b60 ("drm/i915: Import the kfence selftests for i915_sw_fence")
Signed-off-by: Colin Ian King <colin.king@canonical.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20170518133942.5660-1-colin.king@canonical.com
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>

drm/i915: Import the kfence selftests for i915_sw_fence

A long time ago, I wrote some selftests for the struct kfence idea. Now
that we have infrastructure in i915/igt for running kselftests, include
some for i915_sw_fence.

v2: INIT_WORK_ONSTACK/destroy_work_on_stack (Mika)

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Mika Kuoppala <mika.kuoppala@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20170517121007.27224-2-chris@chris-wilson.co.uk