[PATCH] drm/amd: fix scheduler fence teardown order

[Christian König]

From: Christian König <christian.koenig at amd.com>

Some fences might be alive even after we have stopped the scheduler leading
to warnings about leaked objects from the SLUB allocator.

Fix this by allocating/freeing the SLUB allocator from the module
init/finfi functions just like we do it for hw fences.

Reported-by: Grazvydas Ignotas <notasas at gmail.com>
Signed-off-by: Christian König <christian.koenig at amd.com>
---
 drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c       |  2 ++
 drivers/gpu/drm/amd/scheduler/gpu_scheduler.c | 13 -------------
 drivers/gpu/drm/amd/scheduler/gpu_scheduler.h |  3 +++
 drivers/gpu/drm/amd/scheduler/sched_fence.c   | 19 +++++++++++++++++++
 4 files changed, 24 insertions(+), 13 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
index c1e7ccb..7224d17 100755
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
@@ -748,6 +748,7 @@ static int __init amdgpu_init(void)
 {
 	amdgpu_sync_init();
 	amdgpu_fence_slab_init();
+	amd_sched_fence_slab_init();
 	if (vgacon_text_force()) {
 		DRM_ERROR("VGACON disables amdgpu kernel modesetting.\n");
 		return -EINVAL;
@@ -767,6 +768,7 @@ static void __exit amdgpu_exit(void)
 	drm_pci_exit(driver, pdriver);
 	amdgpu_unregister_atpx_handler();
 	amdgpu_sync_fini();
+	amd_sched_fence_slab_fini();
 	amdgpu_fence_slab_fini();
 }
 
diff --git a/drivers/gpu/drm/amd/scheduler/gpu_scheduler.c b/drivers/gpu/drm/amd/scheduler/gpu_scheduler.c
index 910b8d5..ffe1f85 100644
--- a/drivers/gpu/drm/amd/scheduler/gpu_scheduler.c
+++ b/drivers/gpu/drm/amd/scheduler/gpu_scheduler.c
@@ -34,9 +34,6 @@ static bool amd_sched_entity_is_ready(struct amd_sched_entity *entity);
 static void amd_sched_wakeup(struct amd_gpu_scheduler *sched);
 static void amd_sched_process_job(struct fence *f, struct fence_cb *cb);
 
-struct kmem_cache *sched_fence_slab;
-atomic_t sched_fence_slab_ref = ATOMIC_INIT(0);
-
 /* Initialize a given run queue struct */
 static void amd_sched_rq_init(struct amd_sched_rq *rq)
 {
@@ -618,13 +615,6 @@ int amd_sched_init(struct amd_gpu_scheduler *sched,
 	INIT_LIST_HEAD(&sched->ring_mirror_list);
 	spin_lock_init(&sched->job_list_lock);
 	atomic_set(&sched->hw_rq_count, 0);
-	if (atomic_inc_return(&sched_fence_slab_ref) == 1) {
-		sched_fence_slab = kmem_cache_create(
-			"amd_sched_fence", sizeof(struct amd_sched_fence), 0,
-			SLAB_HWCACHE_ALIGN, NULL);
-		if (!sched_fence_slab)
-			return -ENOMEM;
-	}
 
 	/* Each scheduler will run on a seperate kernel thread */
 	sched->thread = kthread_run(amd_sched_main, sched, sched->name);
@@ -645,7 +635,4 @@ void amd_sched_fini(struct amd_gpu_scheduler *sched)
 {
 	if (sched->thread)
 		kthread_stop(sched->thread);
-	rcu_barrier();
-	if (atomic_dec_and_test(&sched_fence_slab_ref))
-		kmem_cache_destroy(sched_fence_slab);
 }
diff --git a/drivers/gpu/drm/amd/scheduler/gpu_scheduler.h b/drivers/gpu/drm/amd/scheduler/gpu_scheduler.h
index 7cbbbfb..28a0d8f 100644
--- a/drivers/gpu/drm/amd/scheduler/gpu_scheduler.h
+++ b/drivers/gpu/drm/amd/scheduler/gpu_scheduler.h
@@ -145,6 +145,9 @@ void amd_sched_entity_fini(struct amd_gpu_scheduler *sched,
 			   struct amd_sched_entity *entity);
 void amd_sched_entity_push_job(struct amd_sched_job *sched_job);
 
+int amd_sched_fence_slab_init(void);
+void amd_sched_fence_slab_fini(void);
+
 struct amd_sched_fence *amd_sched_fence_create(
 	struct amd_sched_entity *s_entity, void *owner);
 void amd_sched_fence_scheduled(struct amd_sched_fence *fence);
diff --git a/drivers/gpu/drm/amd/scheduler/sched_fence.c b/drivers/gpu/drm/amd/scheduler/sched_fence.c
index 3653b5a..8c7b5ee 100644
--- a/drivers/gpu/drm/amd/scheduler/sched_fence.c
+++ b/drivers/gpu/drm/amd/scheduler/sched_fence.c
@@ -27,6 +27,25 @@
 #include <drm/drmP.h>
 #include "gpu_scheduler.h"
 
+struct kmem_cache *sched_fence_slab;
+
+int amd_sched_fence_slab_init(void)
+{
+	sched_fence_slab = kmem_cache_create(
+		"amd_sched_fence", sizeof(struct amd_sched_fence), 0,
+		SLAB_HWCACHE_ALIGN, NULL);
+	if (!sched_fence_slab)
+		return -ENOMEM;
+
+	return 0;
+}
+
+void amd_sched_fence_slab_fini(void)
+{
+	rcu_barrier();
+	kmem_cache_destroy(sched_fence_slab);
+}
+
 struct amd_sched_fence *amd_sched_fence_create(struct amd_sched_entity *entity,
 					       void *owner)
 {
-- 
2.5.0