dma-buf: revert "return only unsignaled fences in dma_fence_unwrap_for_each v3"

This reverts commit 8f61973718485f3e89bc4f408f929048b7b47c83.

It turned out that this is not correct. Especially the sync_file info
IOCTL needs to see even signaled fences to correctly report back their
status to userspace.

Instead add the filter in the merge function again where it makes sense.

Signed-off-by: Christian König <christian.koenig@amd.com>
Tested-by: Karolina Drobnik <karolina.drobnik@intel.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220712102849.1562-1-christian.koenig@amd.com

dma-buf: revert "return only unsignaled fences in dma_fence_unwrap_for_each v3"

This reverts commit 8f61973718485f3e89bc4f408f929048b7b47c83.

It turned out that this is not correct. Especially the sync_file info
IOCTL needs to see even signaled fences to correctly report back their
status to userspace.

Instead add the filter in the merge function again where it makes sense.

Signed-off-by: Christian König <christian.koenig@amd.com>
Tested-by: Karolina Drobnik <karolina.drobnik@intel.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220712102849.1562-1-christian.koenig@amd.com

dma-buf: generalize dma_fence unwrap & merging v3

Introduce a dma_fence_unwrap_merge() macro which allows to unwrap fences
which potentially can be containers as well and then merge them back
together into a flat dma_fence_array.

v2: rename the function, add some more comments about how the wrapper is
used, move filtering of signaled fences into the unwrap iterator,
add complex selftest which covers more cases.
v3: fix signaled fence filtering once more

Signed-off-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20220518135844.3338-5-christian.koenig@amd.com

dma-buf: return only unsignaled fences in dma_fence_unwrap_for_each v3

dma_fence_chain containers cleanup signaled fences automatically, so
filter those out from arrays as well.

v2: fix missing walk over the array
v3: massively simplify the patch and actually update the description.

Signed-off-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20220518135844.3338-4-christian.koenig@amd.com

dma-buf: cleanup dma_fence_unwrap implementation

Move the code from the inline functions into exported functions.

Signed-off-by: Christian König <christian.koenig@amd.com>
Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20220518135844.3338-3-christian.koenig@amd.com

dma-buf: add dma_fence_unwrap v2

Add a general purpose helper to deep dive into dma_fence_chain/dma_fence_array
structures and iterate over all the fences in them.

This is useful when we need to flatten out all fences in those structures.

v2: some selftests cleanup, improved function naming and documentation

Signed-off-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20220311110244.1245-1-christian.koenig@amd.com