FAILED: patch "[PATCH] drm/amd: fix scheduler fence teardown order v2" failed to apply to 4.8-stable tree

[<gregkh@linuxfoundation.org>]

The patch below does not apply to the 4.8-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@vger.kernel.org>.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

>From c24784f01549ecdf23fc00d0588423bcf8956714 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Christian=20K=C3=B6nig?= <christian.koenig@amd.com>
Date: Fri, 28 Oct 2016 17:04:07 +0200
Subject: [PATCH] drm/amd: fix scheduler fence teardown order v2
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

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/fini functions just like we do it for hw fences.

v2: make variable static, add link to bug

Fixes: https://bugs.freedesktop.org/show_bug.cgi?id=97500

Reported-by: Grazvydas Ignotas <notasas@gmail.com>
Signed-off-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com> (v1)
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Cc: stable@vger.kernel.org

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
index 71ed27eb3dde..73f2415630f8 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_drv.c
@@ -737,6 +737,7 @@ 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;
@@ -756,6 +757,7 @@ 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 910b8d5b21c5..ffe1f85ce300 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 7cbbbfb502ef..51068e6c3d9a 100644
--- a/drivers/gpu/drm/amd/scheduler/gpu_scheduler.h
+++ b/drivers/gpu/drm/amd/scheduler/gpu_scheduler.h
@@ -30,9 +30,6 @@
 struct amd_gpu_scheduler;
 struct amd_sched_rq;
 
-extern struct kmem_cache *sched_fence_slab;
-extern atomic_t sched_fence_slab_ref;
-
 /**
  * A scheduler entity is a wrapper around a job queue or a group
  * of other entities. Entities take turns emitting jobs from their
@@ -145,6 +142,9 @@ 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 3653b5a40494..88fc2d662579 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"
 
+static 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)
 {