lwn.git/include/linux/dma-fence-unwrap.h, branch docs-fixes

dma-fence: Add helper to sort and deduplicate dma_fence arrays

2025-05-05T17:29:44+00:00

Export a new helper function `dma_fence_dedup_array()` that sorts an array of dma_fence pointers by context, then deduplicates the array by retaining only the most recent fence per context. This utility is useful when merging or optimizing sets of fences where redundant entries from the same context can be pruned. The operation is performed in-place and releases references to dropped fences using dma_fence_put(). v2: - Export this code from dma-fence-unwrap.c(by Christian). v3: - To split this in a dma_buf patch and amd userq patch(by Sunil). - No need to add a new function just re-use existing(by Christian). v4: - Export dma_fence_dedub_array and use it(by Christian). Cc: Alex Deucher Cc: Arunpravin Paneer Selvam Reviewed-by: Sunil Khatri Reviewed-by: Christian König Signed-off-by: Arvind Yadav Signed-off-by: Alex Deucher

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

2022-07-14T12:41:30+00:00

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 Tested-by: Karolina Drobnik Reviewed-by: Alex Deucher Link: https://patchwork.freedesktop.org/patch/msgid/20220712102849.1562-1-christian.koenig@amd.com

dma-buf: generalize dma_fence unwrap & merging v3

2022-05-30T12:24:04+00:00

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 Reviewed-by: Daniel Vetter 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

2022-05-30T12:23:21+00:00

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 Reviewed-by: Daniel Vetter Link: https://patchwork.freedesktop.org/patch/msgid/20220518135844.3338-4-christian.koenig@amd.com

dma-buf: cleanup dma_fence_unwrap implementation

2022-05-30T12:16:32+00:00

Move the code from the inline functions into exported functions. Signed-off-by: Christian König Acked-by: Daniel Vetter Link: https://patchwork.freedesktop.org/patch/msgid/20220518135844.3338-3-christian.koenig@amd.com

dma-buf: add dma_fence_unwrap v2

2022-03-25T13:18:28+00:00

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 Reviewed-by: Daniel Vetter Link: https://patchwork.freedesktop.org/patch/msgid/20220311110244.1245-1-christian.koenig@amd.com