drm/nouveau/vm: make vm refcount into a kref

Never used to be required, but a recent change made it necessary.

Reported-by: Maarten Lankhorst <maarten.lankhorst@canonical.com>
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>

diff --git a/drivers/gpu/drm/nouveau/core/include/subdev/vm.h b/drivers/gpu/drm/nouveau/core/include/subdev/vm.h
index f2e87b1..fcf57fa 100644 (file)
--- a/drivers/gpu/drm/nouveau/core/include/subdev/vm.h
+++ b/drivers/gpu/drm/nouveau/core/include/subdev/vm.h
@@ -55,7 +55,7 @@ struct nouveau_vma {
 struct nouveau_vm {
        struct nouveau_vmmgr *vmm;
        struct nouveau_mm mm;
-       int refcount;
+       struct kref refcount;
 
        struct list_head pgd_list;
        atomic_t engref[NVDEV_SUBDEV_NR];

diff --git a/drivers/gpu/drm/nouveau/core/subdev/vm/base.c b/drivers/gpu/drm/nouveau/core/subdev/vm/base.c
index 67fcb6c..ef3133e 100644 (file)
--- a/drivers/gpu/drm/nouveau/core/subdev/vm/base.c
+++ b/drivers/gpu/drm/nouveau/core/subdev/vm/base.c
@@ -361,7 +361,7 @@ nouveau_vm_create(struct nouveau_vmmgr *vmm, u64 offset, u64 length,
 
        INIT_LIST_HEAD(&vm->pgd_list);
        vm->vmm = vmm;
-       vm->refcount = 1;
+       kref_init(&vm->refcount);
        vm->fpde = offset >> (vmm->pgt_bits + 12);
        vm->lpde = (offset + length - 1) >> (vmm->pgt_bits + 12);
 
@@ -441,8 +441,9 @@ nouveau_vm_unlink(struct nouveau_vm *vm, struct nouveau_gpuobj *mpgd)
 }
 
 static void
-nouveau_vm_del(struct nouveau_vm *vm)
+nouveau_vm_del(struct kref *kref)
 {
+       struct nouveau_vm *vm = container_of(kref, typeof(*vm), refcount);
        struct nouveau_vm_pgd *vpgd, *tmp;
 
        list_for_each_entry_safe(vpgd, tmp, &vm->pgd_list, head) {
@@ -458,27 +459,19 @@ int
 nouveau_vm_ref(struct nouveau_vm *ref, struct nouveau_vm **ptr,
               struct nouveau_gpuobj *pgd)
 {
-       struct nouveau_vm *vm;
-       int ret;
-
-       vm = ref;
-       if (vm) {
-               ret = nouveau_vm_link(vm, pgd);
+       if (ref) {
+               int ret = nouveau_vm_link(ref, pgd);
                if (ret)
                        return ret;
 
-               vm->refcount++;
+               kref_get(&ref->refcount);
        }
 
-       vm = *ptr;
-       *ptr = ref;
-
-       if (vm) {
-               nouveau_vm_unlink(vm, pgd);
-
-               if (--vm->refcount == 0)
-                       nouveau_vm_del(vm);
+       if (*ptr) {
+               nouveau_vm_unlink(*ptr, pgd);
+               kref_put(&(*ptr)->refcount, nouveau_vm_del);
        }
 
+       *ptr = ref;
        return 0;
 }