drm/nouveau/mmu: don't attempt to dereference vmm without valid instance pointer

Fixes oopses in certain failure paths.

Signed-off-by: Ben Skeggs <bskeggs@redhat.com>

diff --git a/drivers/gpu/drm/nouveau/nvkm/subdev/mmu/vmm.c b/drivers/gpu/drm/nouveau/nvkm/subdev/mmu/vmm.c
index de269eb..7459def 100644 (file)
--- a/drivers/gpu/drm/nouveau/nvkm/subdev/mmu/vmm.c
+++ b/drivers/gpu/drm/nouveau/nvkm/subdev/mmu/vmm.c
@@ -1423,7 +1423,7 @@ nvkm_vmm_get(struct nvkm_vmm *vmm, u8 page, u64 size, struct nvkm_vma **pvma)
 void
 nvkm_vmm_part(struct nvkm_vmm *vmm, struct nvkm_memory *inst)
 {
-       if (vmm->func->part && inst) {
+       if (inst && vmm->func->part) {
                mutex_lock(&vmm->mutex);
                vmm->func->part(vmm, inst);
                mutex_unlock(&vmm->mutex);