drm/v3d: Use DRM_GPU_SCHED_STAT_NO_HANG to skip the reset

When a CL/CSD job times out, we check if the GPU has made any progress
since the last timeout. If so, instead of resetting the hardware, we skip
the reset and allow the timer to be rearmed. This gives long-running jobs
a chance to complete.

Instead of manipulating scheduler's internals, inform the scheduler that
the job did not actually timeout and no reset was performed through
the new status code DRM_GPU_SCHED_STAT_NO_HANG.

Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@igalia.com>
Link: https://lore.kernel.org/r/20250714-sched-skip-reset-v6-5-5c5ba4f55039@igalia.com
Signed-off-by: Maíra Canal <mcanal@igalia.com>

Author: mairacanal

drivers/gpu/drm/v3d/v3d_sched.c

@@ -744,16 +744,6 @@ v3d_gpu_reset_for_timeout(struct v3d_dev *v3d, struct drm_sched_job *sched_job)
 	return DRM_GPU_SCHED_STAT_RESET;
 }
 
-static void
-v3d_sched_skip_reset(struct drm_sched_job *sched_job)
-{
-	struct drm_gpu_scheduler *sched = sched_job->sched;
-
-	spin_lock(&sched->job_list_lock);
-	list_add(&sched_job->list, &sched->pending_list);
-	spin_unlock(&sched->job_list_lock);
-}
-
 static enum drm_gpu_sched_stat
 v3d_cl_job_timedout(struct drm_sched_job *sched_job, enum v3d_queue q,
 		    u32 *timedout_ctca, u32 *timedout_ctra)
@@ -772,8 +762,7 @@ v3d_cl_job_timedout(struct drm_sched_job *sched_job, enum v3d_queue q,
 		*timedout_ctca = ctca;
 		*timedout_ctra = ctra;
 
-		v3d_sched_skip_reset(sched_job);
-		return DRM_GPU_SCHED_STAT_RESET;
+		return DRM_GPU_SCHED_STAT_NO_HANG;
 	}
 
 	return v3d_gpu_reset_for_timeout(v3d, sched_job);
@@ -818,8 +807,7 @@ v3d_csd_job_timedout(struct drm_sched_job *sched_job)
 	if (job->timedout_batches != batches) {
 		job->timedout_batches = batches;
 
-		v3d_sched_skip_reset(sched_job);
-		return DRM_GPU_SCHED_STAT_RESET;
+		return DRM_GPU_SCHED_STAT_NO_HANG;
 	}
 
 	return v3d_gpu_reset_for_timeout(v3d, sched_job);