drm/i915/selftests: Always free spinner on __sseu_prepare error

Prepare a nice little onion unwind to ensure that we always free the
spinner if we __sseu_prepare fails.

Fixes: c06ee6f ("drm/i915/selftests: Context SSEU reconfiguration tests")
Reported-by: Radhakrishna Sripada <radhakrishna.sripada@intel.com>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Cc: Radhakrishna Sripada <radhakrishna.sripada@intel.com>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190215195010.16637-1-chris@chris-wilson.co.uk
Reviewed-by: Radhakrishna Sripada <radhakrishna.sripada@intel.com>

drivers/gpu/drm/i915/selftests/i915_gem_context.c

@@ -710,47 +710,45 @@ __sseu_prepare(struct drm_i915_private *i915,
 	       unsigned int flags,
 	       struct i915_gem_context *ctx,
 	       struct intel_engine_cs *engine,
-	       struct igt_spinner **spin_out)
+	       struct igt_spinner **spin)
 {
-	int ret = 0;
-
-	if (flags & (TEST_BUSY | TEST_RESET)) {
-		struct igt_spinner *spin;
-		struct i915_request *rq;
+	struct i915_request *rq;
+	int ret;
 
-		spin = kzalloc(sizeof(*spin), GFP_KERNEL);
-		if (!spin) {
-			ret = -ENOMEM;
-			goto out;
-		}
+	*spin = NULL;
+	if (!(flags & (TEST_BUSY | TEST_RESET)))
+		return 0;
 
-		ret = igt_spinner_init(spin, i915);
-		if (ret)
-			return ret;
+	*spin = kzalloc(sizeof(**spin), GFP_KERNEL);
+	if (!*spin)
+		return -ENOMEM;
 
-		rq = igt_spinner_create_request(spin, ctx, engine, MI_NOOP);
-		if (IS_ERR(rq)) {
-			ret = PTR_ERR(rq);
-			igt_spinner_fini(spin);
-			kfree(spin);
-			goto out;
-		}
+	ret = igt_spinner_init(*spin, i915);
+	if (ret)
+		goto err_free;
 
-		i915_request_add(rq);
+	rq = igt_spinner_create_request(*spin, ctx, engine, MI_NOOP);
+	if (IS_ERR(rq)) {
+		ret = PTR_ERR(rq);
+		goto err_fini;
+	}
 
-		if (!igt_wait_for_spinner(spin, rq)) {
-			pr_err("%s: Spinner failed to start!\n", name);
-			igt_spinner_end(spin);
-			igt_spinner_fini(spin);
-			kfree(spin);
-			ret = -ETIMEDOUT;
-			goto out;
-		}
+	i915_request_add(rq);
 
-		*spin_out = spin;
+	if (!igt_wait_for_spinner(*spin, rq)) {
+		pr_err("%s: Spinner failed to start!\n", name);
+		ret = -ETIMEDOUT;
+		goto err_end;
 	}
 
-out:
+	return 0;
+
+err_end:
+	igt_spinner_end(*spin);
+err_fini:
+	igt_spinner_fini(*spin);
+err_free:
+	kfree(fetch_and_zero(spin));
 	return ret;
 }
 
@@ -897,22 +895,23 @@ __sseu_test(struct drm_i915_private *i915,
 
 	ret = __sseu_prepare(i915, name, flags, ctx, engine, &spin);
 	if (ret)
-		goto out;
+		goto out_context;
 
 	ret = __i915_gem_context_reconfigure_sseu(ctx, engine, sseu);
 	if (ret)
-		goto out;
+		goto out_spin;
 
 	ret = __sseu_finish(i915, name, flags, ctx, kctx, engine, obj,
 			    hweight32(sseu.slice_mask), spin);
 
-out:
+out_spin:
 	if (spin) {
 		igt_spinner_end(spin);
 		igt_spinner_fini(spin);
 		kfree(spin);
 	}
 
+out_context:
 	kernel_context_close(kctx);
 
 	return ret;