drm/i915: Import the kfence selftests for i915_sw_fence

A long time ago, I wrote some selftests for the struct kfence idea. Now
that we have infrastructure in i915/igt for running kselftests, include
some for i915_sw_fence.

v2: INIT_WORK_ONSTACK/destroy_work_on_stack (Mika)
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Mika Kuoppala <mika.kuoppala@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20170517121007.27224-2-chris@chris-wilson.co.uk

drivers/gpu/drm/i915/Kconfig.debug

@@ -61,6 +61,18 @@ config DRM_I915_SW_FENCE_DEBUG_OBJECTS
 
           If in doubt, say "N".
 
+config DRM_I915_SW_FENCE_CHECK_DAG
+        bool "Enable additional driver debugging for detecting dependency cycles"
+        depends on DRM_I915
+        default n
+        help
+          Choose this option to turn on extra driver debugging that may affect
+          performance but will catch some internal issues.
+
+          Recommended for driver developers only.
+
+          If in doubt, say "N".
+
 config DRM_I915_SELFTEST
 	bool "Enable selftests upon driver load"
 	depends on DRM_I915

drivers/gpu/drm/i915/i915_sw_fence.c

@@ -12,6 +12,7 @@
 #include <linux/reservation.h>
 
 #include "i915_sw_fence.h"
+#include "i915_selftest.h"
 
 #define I915_SW_FENCE_FLAG_ALLOC BIT(3) /* after WQ_FLAG_* for safety */
 
@@ -274,7 +275,7 @@ static bool i915_sw_fence_check_if_after(struct i915_sw_fence *fence,
 	unsigned long flags;
 	bool err;
 
-	if (!IS_ENABLED(CONFIG_I915_SW_FENCE_CHECK_DAG))
+	if (!IS_ENABLED(CONFIG_DRM_I915_SW_FENCE_CHECK_DAG))
 		return false;
 
 	spin_lock_irqsave(&i915_sw_fence_lock, flags);
@@ -490,3 +491,7 @@ int i915_sw_fence_await_reservation(struct i915_sw_fence *fence,
 
 	return ret;
 }
+
+#if IS_ENABLED(CONFIG_DRM_I915_SELFTEST)
+#include "selftests/i915_sw_fence.c"
+#endif

drivers/gpu/drm/i915/selftests/i915_mock_selftests.h

@@ -9,6 +9,7 @@
  * Tests are executed in order by igt/drv_selftest
  */
 selftest(sanitycheck, i915_mock_sanitycheck) /* keep first (igt selfcheck) */
+selftest(fence, i915_sw_fence_mock_selftests)
 selftest(scatterlist, scatterlist_mock_selftests)
 selftest(syncmap, i915_syncmap_mock_selftests)
 selftest(uncore, intel_uncore_mock_selftests)

drivers/gpu/drm/i915/selftests/i915_sw_fence.c

+/*
+ * Copyright © 2017 Intel Corporation
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+ * IN THE SOFTWARE.
+ *
+ */
+
+#include <linux/completion.h>
+#include <linux/delay.h>
+
+#include "../i915_selftest.h"
+
+static int __i915_sw_fence_call
+fence_notify(struct i915_sw_fence *fence, enum i915_sw_fence_notify state)
+{
+	switch (state) {
+	case FENCE_COMPLETE:
+		break;
+
+	case FENCE_FREE:
+		/* Leave the fence for the caller to free it after testing */
+		break;
+	}
+
+	return NOTIFY_DONE;
+}
+
+static struct i915_sw_fence *alloc_fence(void)
+{
+	struct i915_sw_fence *fence;
+
+	fence = kmalloc(sizeof(*fence), GFP_KERNEL);
+	if (!fence)
+		return NULL;
+
+	i915_sw_fence_init(fence, fence_notify);
+	return fence;
+}
+
+static void free_fence(struct i915_sw_fence *fence)
+{
+	i915_sw_fence_fini(fence);
+	kfree(fence);
+}
+
+static int __test_self(struct i915_sw_fence *fence)
+{
+	if (i915_sw_fence_done(fence))
+		return -EINVAL;
+
+	i915_sw_fence_commit(fence);
+	if (!i915_sw_fence_done(fence))
+		return -EINVAL;
+
+	i915_sw_fence_wait(fence);
+	if (!i915_sw_fence_done(fence))
+		return -EINVAL;
+
+	return 0;
+}
+
+static int test_self(void *arg)
+{
+	struct i915_sw_fence *fence;
+	int ret;
+
+	/* Test i915_sw_fence signaling and completion testing */
+	fence = alloc_fence();
+	if (!fence)
+		return -ENOMEM;
+
+	ret = __test_self(fence);
+
+	free_fence(fence);
+	return ret;
+}
+
+static int test_dag(void *arg)
+{
+	struct i915_sw_fence *A, *B, *C;
+	int ret = -EINVAL;
+
+	/* Test detection of cycles within the i915_sw_fence graphs */
+	if (!IS_ENABLED(CONFIG_DRM_I915_SW_FENCE_CHECK_DAG))
+		return 0;
+
+	A = alloc_fence();
+	if (!A)
+		return -ENOMEM;
+
+	if (i915_sw_fence_await_sw_fence_gfp(A, A, GFP_KERNEL) != -EINVAL) {
+		pr_err("recursive cycle not detected (AA)\n");
+		goto err_A;
+	}
+
+	B = alloc_fence();
+	if (!B) {
+		ret = -ENOMEM;
+		goto err_A;
+	}
+
+	i915_sw_fence_await_sw_fence_gfp(A, B, GFP_KERNEL);
+	if (i915_sw_fence_await_sw_fence_gfp(B, A, GFP_KERNEL) != -EINVAL) {
+		pr_err("single depth cycle not detected (BAB)\n");
+		goto err_B;
+	}
+
+	C = alloc_fence();
+	if (i915_sw_fence_await_sw_fence_gfp(B, C, GFP_KERNEL) == -EINVAL) {
+		pr_err("invalid cycle detected\n");
+		goto err_C;
+	}
+	if (i915_sw_fence_await_sw_fence_gfp(C, B, GFP_KERNEL) != -EINVAL) {
+		pr_err("single depth cycle not detected (CBC)\n");
+		goto err_C;
+	}
+	if (i915_sw_fence_await_sw_fence_gfp(C, A, GFP_KERNEL) != -EINVAL) {
+		pr_err("cycle not detected (BA, CB, AC)\n");
+		goto err_C;
+	}
+	if (i915_sw_fence_await_sw_fence_gfp(A, C, GFP_KERNEL) == -EINVAL) {
+		pr_err("invalid cycle detected\n");
+		goto err_C;
+	}
+
+	i915_sw_fence_commit(A);
+	i915_sw_fence_commit(B);
+	i915_sw_fence_commit(C);
+
+	ret = 0;
+	if (!i915_sw_fence_done(C)) {
+		pr_err("fence C not done\n");
+		ret = -EINVAL;
+	}
+	if (!i915_sw_fence_done(B)) {
+		pr_err("fence B not done\n");
+		ret = -EINVAL;
+	}
+	if (!i915_sw_fence_done(A)) {
+		pr_err("fence A not done\n");
+		ret = -EINVAL;
+	}
+err_C:
+	free_fence(C);
+err_B:
+	free_fence(B);
+err_A:
+	free_fence(A);
+	return ret;
+}
+
+static int test_AB(void *arg)
+{
+	struct i915_sw_fence *A, *B;
+	int ret;
+
+	/* Test i915_sw_fence (A) waiting on an event source (B) */
+	A = alloc_fence();
+	if (!A)
+		return -ENOMEM;
+	B = alloc_fence();
+	if (!B) {
+		ret = -ENOMEM;
+		goto err_A;
+	}
+
+	ret = i915_sw_fence_await_sw_fence_gfp(A, B, GFP_KERNEL);
+	if (ret < 0)
+		goto err_B;
+	if (ret == 0) {
+		pr_err("Incorrectly reported fence A was complete before await\n");
+		ret = -EINVAL;
+		goto err_B;
+	}
+
+	ret = -EINVAL;
+	i915_sw_fence_commit(A);
+	if (i915_sw_fence_done(A))
+		goto err_B;
+
+	i915_sw_fence_commit(B);
+	if (!i915_sw_fence_done(B)) {
+		pr_err("Fence B is not done\n");
+		goto err_B;
+	}
+
+	if (!i915_sw_fence_done(A)) {
+		pr_err("Fence A is not done\n");
+		goto err_B;
+	}
+
+	ret = 0;
+err_B:
+	free_fence(B);
+err_A:
+	free_fence(A);
+	return ret;
+}
+
+static int test_ABC(void *arg)
+{
+	struct i915_sw_fence *A, *B, *C;
+	int ret;
+
+	/* Test a chain of fences, A waits on B who waits on C */
+	A = alloc_fence();
+	if (!A)
+		return -ENOMEM;
+
+	B = alloc_fence();
+	if (!B) {
+		ret = -ENOMEM;
+		goto err_A;
+	}
+
+	C = alloc_fence();
+	if (!C) {
+		ret = -ENOMEM;
+		goto err_B;
+	}
+
+	ret = i915_sw_fence_await_sw_fence_gfp(A, B, GFP_KERNEL);
+	if (ret < 0)
+		goto err_C;
+	if (ret == 0) {
+		pr_err("Incorrectly reported fence B was complete before await\n");
+		goto err_C;
+	}
+
+	ret = i915_sw_fence_await_sw_fence_gfp(B, C, GFP_KERNEL);
+	if (ret < 0)
+		goto err_C;
+	if (ret == 0) {
+		pr_err("Incorrectly reported fence C was complete before await\n");
+		goto err_C;
+	}
+
+	ret = -EINVAL;
+	i915_sw_fence_commit(A);
+	if (i915_sw_fence_done(A)) {
+		pr_err("Fence A completed early\n");
+		goto err_C;
+	}
+
+	i915_sw_fence_commit(B);
+	if (i915_sw_fence_done(B)) {
+		pr_err("Fence B completed early\n");
+		goto err_C;
+	}
+
+	if (i915_sw_fence_done(A)) {
+		pr_err("Fence A completed early (after signaling B)\n");
+		goto err_C;
+	}
+
+	i915_sw_fence_commit(C);
+
+	ret = 0;
+	if (!i915_sw_fence_done(C)) {
+		pr_err("Fence C not done\n");
+		ret = -EINVAL;
+	}
+	if (!i915_sw_fence_done(B)) {
+		pr_err("Fence B not done\n");
+		ret = -EINVAL;
+	}
+	if (!i915_sw_fence_done(A)) {
+		pr_err("Fence A not done\n");
+		ret = -EINVAL;
+	}
+err_C:
+	free_fence(C);
+err_B:
+	free_fence(B);
+err_A:
+	free_fence(A);
+	return ret;
+}
+
+static int test_AB_C(void *arg)
+{
+	struct i915_sw_fence *A, *B, *C;
+	int ret = -EINVAL;
+
+	/* Test multiple fences (AB) waiting on a single event (C) */
+	A = alloc_fence();
+	if (!A)
+		return -ENOMEM;
+
+	B = alloc_fence();
+	if (!B) {
+		ret = -ENOMEM;
+		goto err_A;
+	}
+
+	C = alloc_fence();
+	if (!B) {
+		ret = -ENOMEM;
+		goto err_B;
+	}
+
+	ret = i915_sw_fence_await_sw_fence_gfp(A, C, GFP_KERNEL);
+	if (ret < 0)
+		goto err_C;
+	if (ret == 0) {
+		ret = -EINVAL;
+		goto err_C;
+	}
+
+	ret = i915_sw_fence_await_sw_fence_gfp(B, C, GFP_KERNEL);
+	if (ret < 0)
+		goto err_C;
+	if (ret == 0) {
+		ret = -EINVAL;
+		goto err_C;
+	}
+
+	i915_sw_fence_commit(A);
+	i915_sw_fence_commit(B);
+
+	ret = 0;
+	if (i915_sw_fence_done(A)) {
+		pr_err("Fence A completed early\n");
+		ret = -EINVAL;
+	}
+
+	if (i915_sw_fence_done(B)) {
+		pr_err("Fence B completed early\n");
+		ret = -EINVAL;
+	}
+
+	i915_sw_fence_commit(C);
+	if (!i915_sw_fence_done(C)) {
+		pr_err("Fence C not done\n");
+		ret = -EINVAL;
+	}
+
+	if (!i915_sw_fence_done(B)) {
+		pr_err("Fence B not done\n");
+		ret = -EINVAL;
+	}
+
+	if (!i915_sw_fence_done(A)) {
+		pr_err("Fence A not done\n");
+		ret = -EINVAL;
+	}
+
+err_C:
+	free_fence(C);
+err_B:
+	free_fence(B);
+err_A:
+	free_fence(A);
+	return ret;
+}
+
+static int test_C_AB(void *arg)
+{
+	struct i915_sw_fence *A, *B, *C;
+	int ret;
+
+	/* Test multiple event sources (A,B) for a single fence (C) */
+	A = alloc_fence();
+	if (!A)
+		return -ENOMEM;
+
+	B = alloc_fence();
+	if (!B) {
+		ret = -ENOMEM;
+		goto err_A;
+	}
+
+	C = alloc_fence();
+	if (!B) {
+		ret = -ENOMEM;
+		goto err_B;
+	}
+
+	ret = i915_sw_fence_await_sw_fence_gfp(C, A, GFP_KERNEL);
+	if (ret < 0)
+		goto err_C;
+	if (ret == 0) {
+		ret = -EINVAL;
+		goto err_C;
+	}
+
+	ret = i915_sw_fence_await_sw_fence_gfp(C, B, GFP_KERNEL);
+	if (ret < 0)
+		goto err_C;
+	if (ret == 0) {
+		ret = -EINVAL;
+		goto err_C;
+	}
+
+	ret = 0;
+	i915_sw_fence_commit(C);
+	if (i915_sw_fence_done(C))
+		ret = -EINVAL;
+
+	i915_sw_fence_commit(A);
+	i915_sw_fence_commit(B);
+
+	if (!i915_sw_fence_done(A)) {
+		pr_err("Fence A not done\n");
+		ret = -EINVAL;
+	}
+
+	if (!i915_sw_fence_done(B)) {
+		pr_err("Fence B not done\n");
+		ret = -EINVAL;
+	}
+
+	if (!i915_sw_fence_done(C)) {
+		pr_err("Fence C not done\n");
+		ret = -EINVAL;
+	}
+
+err_C:
+	free_fence(C);
+err_B:
+	free_fence(B);
+err_A:
+	free_fence(A);
+	return ret;
+}
+
+static int test_chain(void *arg)
+{
+	int nfences = 4096;
+	struct i915_sw_fence **fences;
+	int ret, i;
+
+	/* Test a long chain of fences */
+	fences = kmalloc_array(nfences, sizeof(*fences), GFP_KERNEL);
+	if (!fences)
+		return -ENOMEM;
+
+	for (i = 0; i < nfences; i++) {
+		fences[i] = alloc_fence();
+		if (!fences[i]) {
+			nfences = i;
+			ret = -ENOMEM;
+			goto err;
+		}
+
+		if (i > 0) {
+			ret = i915_sw_fence_await_sw_fence_gfp(fences[i],
+							       fences[i - 1],
+							       GFP_KERNEL);
+			if (ret < 0) {
+				nfences = i + 1;
+				goto err;
+			}
+
+			i915_sw_fence_commit(fences[i]);
+		}
+	}
+
+	ret = 0;
+	for (i = nfences; --i; ) {
+		if (i915_sw_fence_done(fences[i])) {
+			if (ret == 0)
+				pr_err("Fence[%d] completed early\n", i);
+			ret = -EINVAL;
+		}
+	}
+	i915_sw_fence_commit(fences[0]);
+	for (i = 0; ret == 0 && i < nfences; i++) {
+		if (!i915_sw_fence_done(fences[i])) {
+			pr_err("Fence[%d] is not done\n", i);
+			ret = -EINVAL;
+		}
+	}
+
+err:
+	for (i = 0; i < nfences; i++)
+		free_fence(fences[i]);
+	kfree(fences);
+	return ret;
+}
+
+struct task_ipc {
+	struct work_struct work;
+	struct completion started;
+	struct i915_sw_fence *in, *out;
+	int value;
+};
+
+static void task_ipc(struct work_struct *work)
+{
+	struct task_ipc *ipc = container_of(work, typeof(*ipc), work);
+
+	complete(&ipc->started);
+
+	i915_sw_fence_wait(ipc->in);
+	smp_store_mb(ipc->value, 1);
+	i915_sw_fence_commit(ipc->out);
+}
+
+static int test_ipc(void *arg)
+{
+	struct task_ipc ipc;
+	int ret = 0;
+
+	/* Test use of i915_sw_fence as an interprocess signaling mechanism */
+	ipc.in = alloc_fence();
+	if (!ipc.in)
+		return -ENOMEM;
+	ipc.out = alloc_fence();
+	if (!ipc.out) {
+		ret = -ENOMEM;
+		goto err_in;
+	}
+
+	/* use a completion to avoid chicken-and-egg testing */
+	init_completion(&ipc.started);
+
+	ipc.value = 0;
+	INIT_WORK_ONSTACK(&ipc.work, task_ipc);
+	schedule_work(&ipc.work);
+
+	wait_for_completion(&ipc.started);
+
+	usleep_range(1000, 2000);
+	if (READ_ONCE(ipc.value)) {
+		pr_err("worker updated value before i915_sw_fence was signaled\n");
+		ret = -EINVAL;
+	}
+
+	i915_sw_fence_commit(ipc.in);
+	i915_sw_fence_wait(ipc.out);
+
+	if (!READ_ONCE(ipc.value)) {
+		pr_err("worker signaled i915_sw_fence before value was posted\n");
+		ret = -EINVAL;
+	}
+
+	flush_work(&ipc.work);
+	destroy_work_on_stack(&ipc.work);
+	free_fence(ipc.out);
+err_in:
+	free_fence(ipc.in);
+	return ret;
+}
+
+int i915_sw_fence_mock_selftests(void)
+{
+	static const struct i915_subtest tests[] = {
+		SUBTEST(test_self),
+		SUBTEST(test_dag),
+		SUBTEST(test_AB),
+		SUBTEST(test_ABC),
+		SUBTEST(test_AB_C),
+		SUBTEST(test_C_AB),
+		SUBTEST(test_chain),
+		SUBTEST(test_ipc),
+	};
+
+	return i915_subtests(tests, NULL);
+}