drm/i915: Consolidate i915_vma_unpin_and_release()

In a few places, we repeat a call to clear a pointer to a vma whilst
unpinning and releasing a reference to its owner. Refactor those into a
common function.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1471254551-25805-26-git-send-email-chris@chris-wilson.co.uk

drivers/gpu/drm/i915/i915_gem_gtt.c

@@ -3674,3 +3674,15 @@ void __iomem *i915_vma_pin_iomap(struct i915_vma *vma)
 	__i915_vma_pin(vma);
 	return ptr;
 }
+
+void i915_vma_unpin_and_release(struct i915_vma **p_vma)
+{
+	struct i915_vma *vma;
+
+	vma = fetch_and_zero(p_vma);
+	if (!vma)
+		return;
+
+	i915_vma_unpin(vma);
+	i915_vma_put(vma);
+}

drivers/gpu/drm/i915/i915_gem_gtt.h

@@ -232,6 +232,7 @@ struct i915_vma *
 i915_vma_create(struct drm_i915_gem_object *obj,
 		struct i915_address_space *vm,
 		const struct i915_ggtt_view *view);
+void i915_vma_unpin_and_release(struct i915_vma **p_vma);
 
 static inline bool i915_vma_is_ggtt(const struct i915_vma *vma)
 {

drivers/gpu/drm/i915/i915_guc_submission.c

@@ -653,19 +653,6 @@ static struct i915_vma *guc_allocate_vma(struct intel_guc *guc, u32 size)
 	return vma;
 }
 
-/**
- * guc_release_vma() - Release gem object allocated for GuC usage
- * @vma:	gem obj to be released
- */
-static void guc_release_vma(struct i915_vma *vma)
-{
-	if (!vma)
-		return;
-
-	i915_vma_unpin(vma);
-	i915_vma_put(vma);
-}
-
 static void
 guc_client_free(struct drm_i915_private *dev_priv,
 		struct i915_guc_client *client)
@@ -690,7 +677,7 @@ guc_client_free(struct drm_i915_private *dev_priv,
 		kunmap(kmap_to_page(client->client_base));
 	}
 
-	guc_release_vma(client->vma);
+	i915_vma_unpin_and_release(&client->vma);
 
 	if (client->ctx_index != GUC_INVALID_CTX_ID) {
 		guc_fini_ctx_desc(guc, client);
@@ -1048,12 +1035,12 @@ void i915_guc_submission_fini(struct drm_i915_private *dev_priv)
 {
 	struct intel_guc *guc = &dev_priv->guc;
 
-	guc_release_vma(fetch_and_zero(&guc->ads_vma));
-	guc_release_vma(fetch_and_zero(&guc->log_vma));
+	i915_vma_unpin_and_release(&guc->ads_vma);
+	i915_vma_unpin_and_release(&guc->log_vma);
 
 	if (guc->ctx_pool_vma)
 		ida_destroy(&guc->ctx_ids);
-	guc_release_vma(fetch_and_zero(&guc->ctx_pool_vma));
+	i915_vma_unpin_and_release(&guc->ctx_pool_vma);
 }
 
 /**

drivers/gpu/drm/i915/intel_engine_cs.c

@@ -279,14 +279,7 @@ int intel_engine_create_scratch(struct intel_engine_cs *engine, int size)
 
 static void intel_engine_cleanup_scratch(struct intel_engine_cs *engine)
 {
-	struct i915_vma *vma;
-
-	vma = fetch_and_zero(&engine->scratch);
-	if (!vma)
-		return;
-
-	i915_vma_unpin(vma);
-	i915_vma_put(vma);
+	i915_vma_unpin_and_release(&engine->scratch);
 }
 
 /**

drivers/gpu/drm/i915/intel_lrc.c

@@ -1193,14 +1193,7 @@ static int lrc_setup_wa_ctx_obj(struct intel_engine_cs *engine, u32 size)
 
 static void lrc_destroy_wa_ctx_obj(struct intel_engine_cs *engine)
 {
-	struct i915_vma *vma;
-
-	vma = fetch_and_zero(&engine->wa_ctx.vma);
-	if (!vma)
-		return;
-
-	i915_vma_unpin(vma);
-	i915_vma_put(vma);
+	i915_vma_unpin_and_release(&engine->wa_ctx.vma);
 }
 
 static int intel_init_workaround_bb(struct intel_engine_cs *engine)

drivers/gpu/drm/i915/intel_ringbuffer.c

@@ -1257,14 +1257,8 @@ static int init_render_ring(struct intel_engine_cs *engine)
 static void render_ring_cleanup(struct intel_engine_cs *engine)
 {
 	struct drm_i915_private *dev_priv = engine->i915;
-	struct i915_vma *vma;
-
-	vma = fetch_and_zero(&dev_priv->semaphore);
-	if (!vma)
-		return;
 
-	i915_vma_unpin(vma);
-	i915_vma_put(vma);
+	i915_vma_unpin_and_release(&dev_priv->semaphore);
 }
 
 static int gen8_rcs_signal(struct drm_i915_gem_request *req)