drm/nouveau: don't fini scheduler if not initialized

nouveau_abi16_ioctl_channel_alloc() and nouveau_cli_init() simply call
their corresponding *_fini() counterpart. This can lead to
nouveau_sched_fini() being called without struct nouveau_sched ever
being initialized in the first place.

Instead of embedding struct nouveau_sched into struct nouveau_cli and
struct nouveau_chan_abi16, allocate struct nouveau_sched separately,
such that we can check for the corresponding pointer to be NULL in the
particular *_fini() functions.

It makes sense to allocate struct nouveau_sched separately anyway, since
in a subsequent commit we can also avoid to allocate a struct
nouveau_sched in nouveau_abi16_ioctl_channel_alloc() at all, if the
VM_BIND uAPI has been disabled due to the legacy uAPI being used.

Fixes: 5f03a507b2 ("drm/nouveau: implement 1:1 scheduler - entity relationship")
Reported-by: Timur Tabi <ttabi@nvidia.com>
Tested-by: Timur Tabi <ttabi@nvidia.com>
Closes: https://lore.kernel.org/nouveau/20240131213917.1545604-1-ttabi@nvidia.com/
Reviewed-by: Dave Airlie <airlied@redhat.com>
Signed-off-by: Danilo Krummrich <dakr@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240202000606.3526-1-dakr@redhat.com

drivers/gpu/drm/nouveau/nouveau_abi16.c

@@ -128,12 +128,14 @@ nouveau_abi16_chan_fini(struct nouveau_abi16 *abi16,
 	struct nouveau_abi16_ntfy *ntfy, *temp;
 
 	/* Cancel all jobs from the entity's queue. */
-	drm_sched_entity_fini(&chan->sched.entity);
+	if (chan->sched)
+		drm_sched_entity_fini(&chan->sched->entity);
 
 	if (chan->chan)
 		nouveau_channel_idle(chan->chan);
 
-	nouveau_sched_fini(&chan->sched);
+	if (chan->sched)
+		nouveau_sched_destroy(&chan->sched);
 
 	/* cleanup notifier state */
 	list_for_each_entry_safe(ntfy, temp, &chan->notifiers, head) {
@@ -337,8 +339,8 @@ nouveau_abi16_ioctl_channel_alloc(ABI16_IOCTL_ARGS)
 	if (ret)
 		goto done;
 
-	ret = nouveau_sched_init(&chan->sched, drm, drm->sched_wq,
-				 chan->chan->dma.ib_max);
+	ret = nouveau_sched_create(&chan->sched, drm, drm->sched_wq,
+				   chan->chan->dma.ib_max);
 	if (ret)
 		goto done;
 

drivers/gpu/drm/nouveau/nouveau_abi16.h

@@ -26,7 +26,7 @@ struct nouveau_abi16_chan {
 	struct nouveau_bo *ntfy;
 	struct nouveau_vma *ntfy_vma;
 	struct nvkm_mm  heap;
-	struct nouveau_sched sched;
+	struct nouveau_sched *sched;
 };
 
 struct nouveau_abi16 {

drivers/gpu/drm/nouveau/nouveau_drm.c

@@ -201,7 +201,8 @@ nouveau_cli_fini(struct nouveau_cli *cli)
 	WARN_ON(!list_empty(&cli->worker));
 
 	usif_client_fini(cli);
-	nouveau_sched_fini(&cli->sched);
+	if (cli->sched)
+		nouveau_sched_destroy(&cli->sched);
 	if (uvmm)
 		nouveau_uvmm_fini(uvmm);
 	nouveau_vmm_fini(&cli->svm);
@@ -311,7 +312,7 @@ nouveau_cli_init(struct nouveau_drm *drm, const char *sname,
 	cli->mem = &mems[ret];
 
 	/* Don't pass in the (shared) sched_wq in order to let
-	 * nouveau_sched_init() create a dedicated one for VM_BIND jobs.
+	 * nouveau_sched_create() create a dedicated one for VM_BIND jobs.
 	 *
 	 * This is required to ensure that for VM_BIND jobs free_job() work and
 	 * run_job() work can always run concurrently and hence, free_job() work
@@ -320,7 +321,7 @@ nouveau_cli_init(struct nouveau_drm *drm, const char *sname,
 	 * locks which indirectly or directly are held for allocations
 	 * elsewhere.
 	 */
-	ret = nouveau_sched_init(&cli->sched, drm, NULL, 1);
+	ret = nouveau_sched_create(&cli->sched, drm, NULL, 1);
 	if (ret)
 		goto done;
 

drivers/gpu/drm/nouveau/nouveau_drv.h

@@ -98,7 +98,7 @@ struct nouveau_cli {
 		bool disabled;
 	} uvmm;
 
-	struct nouveau_sched sched;
+	struct nouveau_sched *sched;
 
 	const struct nvif_mclass *mem;
 

drivers/gpu/drm/nouveau/nouveau_exec.c

@@ -389,7 +389,7 @@ nouveau_exec_ioctl_exec(struct drm_device *dev,
 	if (ret)
 		goto out;
 
-	args.sched = &chan16->sched;
+	args.sched = chan16->sched;
 	args.file_priv = file_priv;
 	args.chan = chan;
 

drivers/gpu/drm/nouveau/nouveau_sched.c

@@ -398,7 +398,7 @@ static const struct drm_sched_backend_ops nouveau_sched_ops = {
 	.free_job = nouveau_sched_free_job,
 };
 
-int
+static int
 nouveau_sched_init(struct nouveau_sched *sched, struct nouveau_drm *drm,
 		   struct workqueue_struct *wq, u32 credit_limit)
 {
@@ -453,7 +453,30 @@ fail_wq:
 	return ret;
 }
 
-void
+int
+nouveau_sched_create(struct nouveau_sched **psched, struct nouveau_drm *drm,
+		     struct workqueue_struct *wq, u32 credit_limit)
+{
+	struct nouveau_sched *sched;
+	int ret;
+
+	sched = kzalloc(sizeof(*sched), GFP_KERNEL);
+	if (!sched)
+		return -ENOMEM;
+
+	ret = nouveau_sched_init(sched, drm, wq, credit_limit);
+	if (ret) {
+		kfree(sched);
+		return ret;
+	}
+
+	*psched = sched;
+
+	return 0;
+}
+
+
+static void
 nouveau_sched_fini(struct nouveau_sched *sched)
 {
 	struct drm_gpu_scheduler *drm_sched = &sched->base;
@@ -471,3 +494,14 @@ nouveau_sched_fini(struct nouveau_sched *sched)
 	if (sched->wq)
 		destroy_workqueue(sched->wq);
 }
+
+void
+nouveau_sched_destroy(struct nouveau_sched **psched)
+{
+	struct nouveau_sched *sched = *psched;
+
+	nouveau_sched_fini(sched);
+	kfree(sched);
+
+	*psched = NULL;
+}

drivers/gpu/drm/nouveau/nouveau_sched.h

@@ -111,8 +111,8 @@ struct nouveau_sched {
 	} job;
 };
 
-int nouveau_sched_init(struct nouveau_sched *sched, struct nouveau_drm *drm,
-		       struct workqueue_struct *wq, u32 credit_limit);
-void nouveau_sched_fini(struct nouveau_sched *sched);
+int nouveau_sched_create(struct nouveau_sched **psched, struct nouveau_drm *drm,
+			 struct workqueue_struct *wq, u32 credit_limit);
+void nouveau_sched_destroy(struct nouveau_sched **psched);
 
 #endif

drivers/gpu/drm/nouveau/nouveau_uvmm.c

@@ -1740,7 +1740,7 @@ nouveau_uvmm_ioctl_vm_bind(struct drm_device *dev,
 	if (ret)
 		return ret;
 
-	args.sched = &cli->sched;
+	args.sched = cli->sched;
 	args.file_priv = file_priv;
 
 	ret = nouveau_uvmm_vm_bind(&args);