drm/nouveau/core/memory: add reference counting

We need to be able to prevent memory from being freed while it's still
mapped in a GPU's address-space.

Will be used by upcoming MMU changes.
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>

drivers/gpu/drm/nouveau/include/nvkm/core/memory.h

@@ -20,6 +20,7 @@ enum nvkm_memory_target {
 struct nvkm_memory {
 	const struct nvkm_memory_func *func;
 	const struct nvkm_memory_ptrs *ptrs;
+	struct kref kref;
 	struct nvkm_tags *tags;
 };
 
@@ -44,7 +45,8 @@ struct nvkm_memory_ptrs {
 void nvkm_memory_ctor(const struct nvkm_memory_func *, struct nvkm_memory *);
 int nvkm_memory_new(struct nvkm_device *, enum nvkm_memory_target,
 		    u64 size, u32 align, bool zero, struct nvkm_memory **);
-void nvkm_memory_del(struct nvkm_memory **);
+struct nvkm_memory *nvkm_memory_ref(struct nvkm_memory *);
+void nvkm_memory_unref(struct nvkm_memory **);
 int nvkm_memory_tags_get(struct nvkm_memory *, struct nvkm_device *, u32 tags,
 			 void (*clear)(struct nvkm_device *, u32, u32),
 			 struct nvkm_tags **);

drivers/gpu/drm/nouveau/nvkm/core/gpuobj.c

@@ -219,7 +219,7 @@ nvkm_gpuobj_del(struct nvkm_gpuobj **pgpuobj)
 		if (gpuobj->parent)
 			nvkm_mm_free(&gpuobj->parent->heap, &gpuobj->node);
 		nvkm_mm_fini(&gpuobj->heap);
-		nvkm_memory_del(&gpuobj->memory);
+		nvkm_memory_unref(&gpuobj->memory);
 		kfree(*pgpuobj);
 		*pgpuobj = NULL;
 	}

drivers/gpu/drm/nouveau/nvkm/core/memory.c

@@ -100,20 +100,38 @@ nvkm_memory_ctor(const struct nvkm_memory_func *func,
 		 struct nvkm_memory *memory)
 {
 	memory->func = func;
+	kref_init(&memory->kref);
+}
+
+static void
+nvkm_memory_del(struct kref *kref)
+{
+	struct nvkm_memory *memory = container_of(kref, typeof(*memory), kref);
+	if (!WARN_ON(!memory->func)) {
+		if (memory->func->dtor)
+			memory = memory->func->dtor(memory);
+		kfree(memory);
+	}
 }
 
 void
-nvkm_memory_del(struct nvkm_memory **pmemory)
+nvkm_memory_unref(struct nvkm_memory **pmemory)
 {
 	struct nvkm_memory *memory = *pmemory;
-	if (memory && !WARN_ON(!memory->func)) {
-		if (memory->func->dtor)
-			*pmemory = memory->func->dtor(memory);
-		kfree(*pmemory);
+	if (memory) {
+		kref_put(&memory->kref, nvkm_memory_del);
 		*pmemory = NULL;
 	}
 }
 
+struct nvkm_memory *
+nvkm_memory_ref(struct nvkm_memory *memory)
+{
+	if (memory)
+		kref_get(&memory->kref);
+	return memory;
+}
+
 int
 nvkm_memory_new(struct nvkm_device *device, enum nvkm_memory_target target,
 		u64 size, u32 align, bool zero,

drivers/gpu/drm/nouveau/nvkm/engine/falcon.c

@@ -99,7 +99,7 @@ nvkm_falcon_fini(struct nvkm_engine *engine, bool suspend)
 	const u32 base = falcon->addr;
 
 	if (!suspend) {
-		nvkm_memory_del(&falcon->core);
+		nvkm_memory_unref(&falcon->core);
 		if (falcon->external) {
 			vfree(falcon->data.data);
 			vfree(falcon->code.data);

drivers/gpu/drm/nouveau/nvkm/engine/fifo/gf100.c

@@ -642,9 +642,9 @@ gf100_fifo_dtor(struct nvkm_fifo *base)
 {
 	struct gf100_fifo *fifo = gf100_fifo(base);
 	nvkm_vm_put(&fifo->user.bar);
-	nvkm_memory_del(&fifo->user.mem);
-	nvkm_memory_del(&fifo->runlist.mem[0]);
-	nvkm_memory_del(&fifo->runlist.mem[1]);
+	nvkm_memory_unref(&fifo->user.mem);
+	nvkm_memory_unref(&fifo->runlist.mem[0]);
+	nvkm_memory_unref(&fifo->runlist.mem[1]);
 	return fifo;
 }
 

drivers/gpu/drm/nouveau/nvkm/engine/fifo/gk104.c

@@ -880,11 +880,11 @@ gk104_fifo_dtor(struct nvkm_fifo *base)
 	int i;
 
 	nvkm_vm_put(&fifo->user.bar);
-	nvkm_memory_del(&fifo->user.mem);
+	nvkm_memory_unref(&fifo->user.mem);
 
 	for (i = 0; i < fifo->runlist_nr; i++) {
-		nvkm_memory_del(&fifo->runlist[i].mem[1]);
-		nvkm_memory_del(&fifo->runlist[i].mem[0]);
+		nvkm_memory_unref(&fifo->runlist[i].mem[1]);
+		nvkm_memory_unref(&fifo->runlist[i].mem[0]);
 	}
 
 	return fifo;

drivers/gpu/drm/nouveau/nvkm/engine/fifo/nv50.c

@@ -100,8 +100,8 @@ void *
 nv50_fifo_dtor(struct nvkm_fifo *base)
 {
 	struct nv50_fifo *fifo = nv50_fifo(base);
-	nvkm_memory_del(&fifo->runlist[1]);
-	nvkm_memory_del(&fifo->runlist[0]);
+	nvkm_memory_unref(&fifo->runlist[1]);
+	nvkm_memory_unref(&fifo->runlist[0]);
 	return fifo;
 }
 

drivers/gpu/drm/nouveau/nvkm/engine/gr/ctxgf100.c

@@ -1380,7 +1380,7 @@ gf100_grctx_generate(struct gf100_gr *gr)
 	}
 
 done:
-	nvkm_memory_del(&chan);
+	nvkm_memory_unref(&chan);
 	return ret;
 }
 

drivers/gpu/drm/nouveau/nvkm/engine/gr/gf100.c

@@ -354,14 +354,14 @@ gf100_gr_chan_dtor(struct nvkm_object *object)
 			nvkm_vm_unmap(&chan->data[i].vma);
 			nvkm_vm_put(&chan->data[i].vma);
 		}
-		nvkm_memory_del(&chan->data[i].mem);
+		nvkm_memory_unref(&chan->data[i].mem);
 	}
 
 	if (chan->mmio_vma.node) {
 		nvkm_vm_unmap(&chan->mmio_vma);
 		nvkm_vm_put(&chan->mmio_vma);
 	}
-	nvkm_memory_del(&chan->mmio);
+	nvkm_memory_unref(&chan->mmio);
 	return chan;
 }
 

drivers/gpu/drm/nouveau/nvkm/engine/gr/nv20.c

@@ -59,7 +59,7 @@ void *
 nv20_gr_chan_dtor(struct nvkm_object *object)
 {
 	struct nv20_gr_chan *chan = nv20_gr_chan(object);
-	nvkm_memory_del(&chan->inst);
+	nvkm_memory_unref(&chan->inst);
 	return chan;
 }
 
@@ -323,7 +323,7 @@ void *
 nv20_gr_dtor(struct nvkm_gr *base)
 {
 	struct nv20_gr *gr = nv20_gr(base);
-	nvkm_memory_del(&gr->ctxtab);
+	nvkm_memory_unref(&gr->ctxtab);
 	return gr;
 }
 

drivers/gpu/drm/nouveau/nvkm/engine/xtensa.c

@@ -86,7 +86,7 @@ nvkm_xtensa_fini(struct nvkm_engine *engine, bool suspend)
 	nvkm_wr32(device, base + 0xd94, 0); /* FIFO_CTRL */
 
 	if (!suspend)
-		nvkm_memory_del(&xtensa->gpu_fw);
+		nvkm_memory_unref(&xtensa->gpu_fw);
 	return 0;
 }
 

drivers/gpu/drm/nouveau/nvkm/subdev/bar/gf100.c

@@ -166,14 +166,14 @@ gf100_bar_dtor(struct nvkm_bar *base)
 
 	nvkm_vm_ref(NULL, &bar->bar[1].vm, bar->bar[1].pgd);
 	nvkm_gpuobj_del(&bar->bar[1].pgd);
-	nvkm_memory_del(&bar->bar[1].mem);
+	nvkm_memory_unref(&bar->bar[1].mem);
 
 	if (bar->bar[0].vm) {
-		nvkm_memory_del(&bar->bar[0].vm->pgt[0].mem[0]);
+		nvkm_memory_unref(&bar->bar[0].vm->pgt[0].mem[0]);
 		nvkm_vm_ref(NULL, &bar->bar[0].vm, bar->bar[0].pgd);
 	}
 	nvkm_gpuobj_del(&bar->bar[0].pgd);
-	nvkm_memory_del(&bar->bar[0].mem);
+	nvkm_memory_unref(&bar->bar[0].mem);
 	return bar;
 }
 

drivers/gpu/drm/nouveau/nvkm/subdev/bar/nv50.c

@@ -201,7 +201,7 @@ nv50_bar_dtor(struct nvkm_bar *base)
 	nvkm_vm_ref(NULL, &bar->bar1_vm, bar->pgd);
 	nvkm_gpuobj_del(&bar->bar2);
 	if (bar->bar2_vm) {
-		nvkm_memory_del(&bar->bar2_vm->pgt[0].mem[0]);
+		nvkm_memory_unref(&bar->bar2_vm->pgt[0].mem[0]);
 		nvkm_vm_ref(NULL, &bar->bar2_vm, bar->pgd);
 	}
 	nvkm_gpuobj_del(&bar->pgd);

drivers/gpu/drm/nouveau/nvkm/subdev/fb/base.c

@@ -163,8 +163,8 @@ nvkm_fb_dtor(struct nvkm_subdev *subdev)
 	struct nvkm_fb *fb = nvkm_fb(subdev);
 	int i;
 
-	nvkm_memory_del(&fb->mmu_wr);
-	nvkm_memory_del(&fb->mmu_rd);
+	nvkm_memory_unref(&fb->mmu_wr);
+	nvkm_memory_unref(&fb->mmu_rd);
 
 	for (i = 0; i < fb->tile.regions; i++)
 		fb->func->tile.fini(fb, i, &fb->tile.region[i]);

drivers/gpu/drm/nouveau/nvkm/subdev/instmem/base.c

@@ -120,7 +120,7 @@ nvkm_instobj_new(struct nvkm_instmem *imem, u32 size, u32 align, bool zero,
 
 done:
 	if (ret)
-		nvkm_memory_del(&memory);
+		nvkm_memory_unref(&memory);
 	*pmemory = memory;
 	return ret;
 }

drivers/gpu/drm/nouveau/nvkm/subdev/instmem/nv04.c

@@ -199,10 +199,10 @@ static void *
 nv04_instmem_dtor(struct nvkm_instmem *base)
 {
 	struct nv04_instmem *imem = nv04_instmem(base);
-	nvkm_memory_del(&imem->base.ramfc);
-	nvkm_memory_del(&imem->base.ramro);
+	nvkm_memory_unref(&imem->base.ramfc);
+	nvkm_memory_unref(&imem->base.ramro);
 	nvkm_ramht_del(&imem->base.ramht);
-	nvkm_memory_del(&imem->base.vbios);
+	nvkm_memory_unref(&imem->base.vbios);
 	nvkm_mm_fini(&imem->heap);
 	return imem;
 }

drivers/gpu/drm/nouveau/nvkm/subdev/instmem/nv40.c

@@ -215,10 +215,10 @@ static void *
 nv40_instmem_dtor(struct nvkm_instmem *base)
 {
 	struct nv40_instmem *imem = nv40_instmem(base);
-	nvkm_memory_del(&imem->base.ramfc);
-	nvkm_memory_del(&imem->base.ramro);
+	nvkm_memory_unref(&imem->base.ramfc);
+	nvkm_memory_unref(&imem->base.ramro);
 	nvkm_ramht_del(&imem->base.ramht);
-	nvkm_memory_del(&imem->base.vbios);
+	nvkm_memory_unref(&imem->base.vbios);
 	nvkm_mm_fini(&imem->heap);
 	if (imem->iomem)
 		iounmap(imem->iomem);

drivers/gpu/drm/nouveau/nvkm/subdev/mmu/base.c

@@ -243,7 +243,7 @@ nvkm_vm_unmap_pgt(struct nvkm_vm *vm, int big, u32 fpde, u32 lpde)
 
 		mmu->func->flush(vm);
 
-		nvkm_memory_del(&pgt);
+		nvkm_memory_unref(&pgt);
 	}
 }
 

drivers/gpu/drm/nouveau/nvkm/subdev/mmu/nv04.c

@@ -106,7 +106,7 @@ nv04_mmu_dtor(struct nvkm_mmu *base)
 	struct nv04_mmu *mmu = nv04_mmu(base);
 	struct nvkm_device *device = mmu->base.subdev.device;
 	if (mmu->base.vmm) {
-		nvkm_memory_del(&mmu->base.vmm->pgt[0].mem[0]);
+		nvkm_memory_unref(&mmu->base.vmm->pgt[0].mem[0]);
 		nvkm_vm_ref(NULL, &mmu->base.vmm, NULL);
 	}
 	if (mmu->nullp) {