drm/nv50/kms: fix pin refcnt leaks

Weren't critical previously, the buffers would go away anyway.  But with
recent changes to core drm/ttm lockdep will get pissed off now, so let's
fix it.
Reported-by: Maarten Lankhorst <maarten.lankhorst@canonical.com>
Signed-off-by: Ben Skeggs <bskeggs@redhat.com>
Acked-by: Maarten Lankhorst <maarten.lankhorst@canonical.com>

drivers/gpu/drm/nouveau/nv50_display.c

@@ -355,6 +355,7 @@ struct nv50_oimm {
 
 struct nv50_head {
 	struct nouveau_crtc base;
+	struct nouveau_bo *image;
 	struct nv50_curs curs;
 	struct nv50_sync sync;
 	struct nv50_ovly ovly;
@@ -517,9 +518,10 @@ nv50_display_flip_next(struct drm_crtc *crtc, struct drm_framebuffer *fb,
 {
 	struct nouveau_framebuffer *nv_fb = nouveau_framebuffer(fb);
 	struct nouveau_crtc *nv_crtc = nouveau_crtc(crtc);
+	struct nv50_head *head = nv50_head(crtc);
 	struct nv50_sync *sync = nv50_sync(crtc);
-	int head = nv_crtc->index, ret;
 	u32 *push;
+	int ret;
 
 	swap_interval <<= 4;
 	if (swap_interval == 0)
@@ -537,7 +539,7 @@ nv50_display_flip_next(struct drm_crtc *crtc, struct drm_framebuffer *fb,
 			return ret;
 
 		BEGIN_NV04(chan, 0, NV11_SUBCHAN_DMA_SEMAPHORE, 2);
-		OUT_RING  (chan, NvEvoSema0 + head);
+		OUT_RING  (chan, NvEvoSema0 + nv_crtc->index);
 		OUT_RING  (chan, sync->addr ^ 0x10);
 		BEGIN_NV04(chan, 0, NV11_SUBCHAN_SEMAPHORE_RELEASE, 1);
 		OUT_RING  (chan, sync->data + 1);
@@ -546,7 +548,7 @@ nv50_display_flip_next(struct drm_crtc *crtc, struct drm_framebuffer *fb,
 		OUT_RING  (chan, sync->data);
 	} else
 	if (chan && nv_mclass(chan->object) < NVC0_CHANNEL_IND_CLASS) {
-		u64 addr = nv84_fence_crtc(chan, head) + sync->addr;
+		u64 addr = nv84_fence_crtc(chan, nv_crtc->index) + sync->addr;
 		ret = RING_SPACE(chan, 12);
 		if (ret)
 			return ret;
@@ -565,7 +567,7 @@ nv50_display_flip_next(struct drm_crtc *crtc, struct drm_framebuffer *fb,
 		OUT_RING  (chan, NV84_SUBCHAN_SEMAPHORE_TRIGGER_ACQUIRE_EQUAL);
 	} else
 	if (chan) {
-		u64 addr = nv84_fence_crtc(chan, head) + sync->addr;
+		u64 addr = nv84_fence_crtc(chan, nv_crtc->index) + sync->addr;
 		ret = RING_SPACE(chan, 10);
 		if (ret)
 			return ret;
@@ -630,6 +632,8 @@ nv50_display_flip_next(struct drm_crtc *crtc, struct drm_framebuffer *fb,
 	evo_mthd(push, 0x0080, 1);
 	evo_data(push, 0x00000000);
 	evo_kick(push, sync);
+
+	nouveau_bo_ref(nv_fb->nvbo, &head->image);
 	return 0;
 }
 
@@ -1038,18 +1042,17 @@ static int
 nv50_crtc_swap_fbs(struct drm_crtc *crtc, struct drm_framebuffer *old_fb)
 {
 	struct nouveau_framebuffer *nvfb = nouveau_framebuffer(crtc->fb);
+	struct nv50_head *head = nv50_head(crtc);
 	int ret;
 
 	ret = nouveau_bo_pin(nvfb->nvbo, TTM_PL_FLAG_VRAM);
-	if (ret)
-		return ret;
-
-	if (old_fb) {
-		nvfb = nouveau_framebuffer(old_fb);
-		nouveau_bo_unpin(nvfb->nvbo);
+	if (ret == 0) {
+		if (head->image)
+			nouveau_bo_unpin(head->image);
+		nouveau_bo_ref(nvfb->nvbo, &head->image);
 	}
 
-	return 0;
+	return ret;
 }
 
 static int
@@ -1198,6 +1201,15 @@ nv50_crtc_lut_load(struct drm_crtc *crtc)
 	}
 }
 
+static void
+nv50_crtc_disable(struct drm_crtc *crtc)
+{
+	struct nv50_head *head = nv50_head(crtc);
+	if (head->image)
+		nouveau_bo_unpin(head->image);
+	nouveau_bo_ref(NULL, &head->image);
+}
+
 static int
 nv50_crtc_cursor_set(struct drm_crtc *crtc, struct drm_file *file_priv,
 		     uint32_t handle, uint32_t width, uint32_t height)
@@ -1271,18 +1283,29 @@ nv50_crtc_destroy(struct drm_crtc *crtc)
 	struct nouveau_crtc *nv_crtc = nouveau_crtc(crtc);
 	struct nv50_disp *disp = nv50_disp(crtc->dev);
 	struct nv50_head *head = nv50_head(crtc);
+
 	nv50_dmac_destroy(disp->core, &head->ovly.base);
 	nv50_pioc_destroy(disp->core, &head->oimm.base);
 	nv50_dmac_destroy(disp->core, &head->sync.base);
 	nv50_pioc_destroy(disp->core, &head->curs.base);
+
+	/*XXX: this shouldn't be necessary, but the core doesn't call
+	 *     disconnect() during the cleanup paths
+	 */
+	if (head->image)
+		nouveau_bo_unpin(head->image);
+	nouveau_bo_ref(NULL, &head->image);
+
 	nouveau_bo_unmap(nv_crtc->cursor.nvbo);
 	if (nv_crtc->cursor.nvbo)
 		nouveau_bo_unpin(nv_crtc->cursor.nvbo);
 	nouveau_bo_ref(NULL, &nv_crtc->cursor.nvbo);
+
 	nouveau_bo_unmap(nv_crtc->lut.nvbo);
 	if (nv_crtc->lut.nvbo)
 		nouveau_bo_unpin(nv_crtc->lut.nvbo);
 	nouveau_bo_ref(NULL, &nv_crtc->lut.nvbo);
+
 	drm_crtc_cleanup(crtc);
 	kfree(crtc);
 }
@@ -1296,6 +1319,7 @@ static const struct drm_crtc_helper_funcs nv50_crtc_hfunc = {
 	.mode_set_base = nv50_crtc_mode_set_base,
 	.mode_set_base_atomic = nv50_crtc_mode_set_base_atomic,
 	.load_lut = nv50_crtc_lut_load,
+	.disable = nv50_crtc_disable,
 };
 
 static const struct drm_crtc_funcs nv50_crtc_func = {