drm/sched: Increment job count before swapping tail spsc queue

2025-07-17T16:35:13+00:00

commit 8af39ec5cf2be522c8eb43a3d8005ed59e4daaee upstream. A small race exists between spsc_queue_push and the run-job worker, in which spsc_queue_push may return not-first while the run-job worker has already idled due to the job count being zero. If this race occurs, job scheduling stops, leading to hangs while waiting on the job’s DMA fences. Seal this race by incrementing the job count before appending to the SPSC queue. This race was observed on a drm-tip 6.16-rc1 build with the Xe driver in an SVM test case. Fixes: 1b1f42d8fde4 ("drm: move amd_gpu_scheduler into common location") Fixes: 27105db6c63a ("drm/amdgpu: Add SPSC queue to scheduler.") Cc: stable@vger.kernel.org Signed-off-by: Matthew Brost Reviewed-by: Jonathan Cavitt Link: https://lore.kernel.org/r/20250613212013.719312-1-matthew.brost@intel.com Signed-off-by: Greg Kroah-Hartman

drm: move amd_gpu_scheduler into common location

2017-12-07T16:51:56+00:00

This moves and renames the AMDGPU scheduler to a common location in DRM in order to facilitate re-use by other drivers. This is mostly a straight forward rename with no code changes. One notable exception is the function to_drm_sched_fence(), which is no longer a inline header function to avoid the need to export the drm_sched_fence_ops_scheduled and drm_sched_fence_ops_finished structures. Reviewed-by: Chunming Zhou Tested-by: Dieter Nützel Acked-by: Alex Deucher Signed-off-by: Lucas Stach Signed-off-by: Alex Deucher

kernel/linux.git/include/drm/spsc_queue.h, branch v6.6.132

drm/sched: Increment job count before swapping tail spsc queue

drm: move amd_gpu_scheduler into common location