Sometimes drivers need to be able to submit multiple jobs which depend on
each other to different schedulers at the same time, but using
drm_sched_job_add_dependency() can't fail any more after the first job is
initialized.
This function preallocate memory for dependency slots so that no ENOMEM
can come later while adding dependencies.
Signed-off-by: Christian König <christian.koe...@amd.com>
---
drivers/gpu/drm/scheduler/sched_main.c | 37 ++++++++++++++++++++++++++
include/drm/gpu_scheduler.h | 2 ++
2 files changed, 39 insertions(+)
diff --git a/drivers/gpu/drm/scheduler/sched_main.c
b/drivers/gpu/drm/scheduler/sched_main.c
index d2d64bf17c96..84713214fbf3 100644
--- a/drivers/gpu/drm/scheduler/sched_main.c
+++ b/drivers/gpu/drm/scheduler/sched_main.c
@@ -858,6 +858,43 @@ void drm_sched_job_arm(struct drm_sched_job *job)
}
EXPORT_SYMBOL(drm_sched_job_arm);
+/**
+ * drm_sched_job_prealloc_dependency_slots - avoid ENOMEM on adding
dependencies
+ * @job: scheduler job where dependencies will be added
+ * @num_slots: number of slots to reserve
+ *
+ * Sometimes drivers need to be able to submit multiple jobs which depend on
+ * each other to different schedulers at the same time, but using
+ * drm_sched_job_add_dependency() can't fail any more after the first job is
+ * initialized.
+ *
+ * This function preallocate memory for dependency slots so that no ENOMEM can
+ * come later while adding dependencies.
+ *
+ * Return:
+ * 0 on success, or an error on failing to expand the array.
+ */
+int drm_sched_job_prealloc_dependency_slots(struct drm_sched_job *job,
+ unsigned int num_slots)
+{
+ int ret;
+ u32 id;
+
+ /*
+ * This works because NULL entries are not returned by xa_for_each. So
+ * drm_sched_job_add_dependency() will ignore those while checking for
+ * duplicates, but can then use the entry when storing the new fence.
+ */
+ while (num_slots--) {
+ ret = xa_alloc(&job->dependencies, &id, NULL, xa_limit_32b,
+ GFP_KERNEL);
+ if (ret)
+ return ret;
+ }
+ return 0;
+}
+EXPORT_SYMBOL(drm_sched_job_prealloc_dependency_slots);
+
/**
* drm_sched_job_add_dependency - adds the fence as a job dependency
* @job: scheduler job to add the dependencies to
diff --git a/include/drm/gpu_scheduler.h b/include/drm/gpu_scheduler.h
index d860db087ea5..a560a00c6275 100644
--- a/include/drm/gpu_scheduler.h
+++ b/include/drm/gpu_scheduler.h
@@ -632,6 +632,8 @@ int drm_sched_job_init(struct drm_sched_job *job,
u32 credits, void *owner);
void drm_sched_job_arm(struct drm_sched_job *job);
void drm_sched_entity_push_job(struct drm_sched_job *sched_job);
+int drm_sched_job_prealloc_dependency_slots(struct drm_sched_job *job,
+ unsigned int num_slots);
int drm_sched_job_add_dependency(struct drm_sched_job *job,
struct dma_fence *fence);
int drm_sched_job_add_syncobj_dependency(struct drm_sched_job *job,
--
2.34.1
