dma-buf: add dma_resv selftest v4

Just exercising a very minor subset of the functionality, but already
proven useful.

v2: add missing locking
v3: some more cleanup and consolidation, add unlocked test as well
v4: add a dma_resv_get_fences selftest

Signed-off-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin@intel.com> (v3)
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch> (v3)
Link: https://patchwork.freedesktop.org/patch/msgid/20211005113742.1101-4-christian.koenig@amd.com

drivers/dma-buf/Makefile

@@ -11,6 +11,7 @@ obj-$(CONFIG_DMABUF_SYSFS_STATS) += dma-buf-sysfs-stats.o
 dmabuf_selftests-y := \
 	selftest.o \
 	st-dma-fence.o \
-	st-dma-fence-chain.o
+	st-dma-fence-chain.o \
+	st-dma-resv.o
 
 obj-$(CONFIG_DMABUF_SELFTESTS)	+= dmabuf_selftests.o

drivers/dma-buf/selftests.h

@@ -12,3 +12,4 @@
 selftest(sanitycheck, __sanitycheck__) /* keep first (igt selfcheck) */
 selftest(dma_fence, dma_fence)
 selftest(dma_fence_chain, dma_fence_chain)
+selftest(dma_resv, dma_resv)

drivers/dma-buf/st-dma-resv.c

@@ -0,0 +1,370 @@
+/* SPDX-License-Identifier: MIT */
+
+/*
+* Copyright © 2019 Intel Corporation
+* Copyright © 2021 Advanced Micro Devices, Inc.
+*/
+
+#include <linux/slab.h>
+#include <linux/spinlock.h>
+#include <linux/dma-resv.h>
+
+#include "selftest.h"
+
+static struct spinlock fence_lock;
+
+static const char *fence_name(struct dma_fence *f)
+{
+	return "selftest";
+}
+
+static const struct dma_fence_ops fence_ops = {
+	.get_driver_name = fence_name,
+	.get_timeline_name = fence_name,
+};
+
+static struct dma_fence *alloc_fence(void)
+{
+	struct dma_fence *f;
+
+	f = kmalloc(sizeof(*f), GFP_KERNEL);
+	if (!f)
+		return NULL;
+
+	dma_fence_init(f, &fence_ops, &fence_lock, 0, 0);
+	return f;
+}
+
+static int sanitycheck(void *arg)
+{
+	struct dma_resv resv;
+	struct dma_fence *f;
+	int r;
+
+	f = alloc_fence();
+	if (!f)
+		return -ENOMEM;
+
+	dma_fence_signal(f);
+	dma_fence_put(f);
+
+	dma_resv_init(&resv);
+	r = dma_resv_lock(&resv, NULL);
+	if (r)
+		pr_err("Resv locking failed\n");
+	else
+		dma_resv_unlock(&resv);
+	dma_resv_fini(&resv);
+	return r;
+}
+
+static int test_signaling(void *arg, bool shared)
+{
+	struct dma_resv resv;
+	struct dma_fence *f;
+	int r;
+
+	f = alloc_fence();
+	if (!f)
+		return -ENOMEM;
+
+	dma_resv_init(&resv);
+	r = dma_resv_lock(&resv, NULL);
+	if (r) {
+		pr_err("Resv locking failed\n");
+		goto err_free;
+	}
+
+	if (shared) {
+		r = dma_resv_reserve_shared(&resv, 1);
+		if (r) {
+			pr_err("Resv shared slot allocation failed\n");
+			goto err_unlock;
+		}
+
+		dma_resv_add_shared_fence(&resv, f);
+	} else {
+		dma_resv_add_excl_fence(&resv, f);
+	}
+
+	if (dma_resv_test_signaled(&resv, shared)) {
+		pr_err("Resv unexpectedly signaled\n");
+		r = -EINVAL;
+		goto err_unlock;
+	}
+	dma_fence_signal(f);
+	if (!dma_resv_test_signaled(&resv, shared)) {
+		pr_err("Resv not reporting signaled\n");
+		r = -EINVAL;
+		goto err_unlock;
+	}
+err_unlock:
+	dma_resv_unlock(&resv);
+err_free:
+	dma_resv_fini(&resv);
+	dma_fence_put(f);
+	return r;
+}
+
+static int test_excl_signaling(void *arg)
+{
+	return test_signaling(arg, false);
+}
+
+static int test_shared_signaling(void *arg)
+{
+	return test_signaling(arg, true);
+}
+
+static int test_for_each(void *arg, bool shared)
+{
+	struct dma_resv_iter cursor;
+	struct dma_fence *f, *fence;
+	struct dma_resv resv;
+	int r;
+
+	f = alloc_fence();
+	if (!f)
+		return -ENOMEM;
+
+	dma_resv_init(&resv);
+	r = dma_resv_lock(&resv, NULL);
+	if (r) {
+		pr_err("Resv locking failed\n");
+		goto err_free;
+	}
+
+	if (shared) {
+		r = dma_resv_reserve_shared(&resv, 1);
+		if (r) {
+			pr_err("Resv shared slot allocation failed\n");
+			goto err_unlock;
+		}
+
+		dma_resv_add_shared_fence(&resv, f);
+	} else {
+		dma_resv_add_excl_fence(&resv, f);
+	}
+
+	r = -ENOENT;
+	dma_resv_for_each_fence(&cursor, &resv, shared, fence) {
+		if (!r) {
+			pr_err("More than one fence found\n");
+			r = -EINVAL;
+			goto err_unlock;
+		}
+		if (f != fence) {
+			pr_err("Unexpected fence\n");
+			r = -EINVAL;
+			goto err_unlock;
+		}
+		if (dma_resv_iter_is_exclusive(&cursor) != !shared) {
+			pr_err("Unexpected fence usage\n");
+			r = -EINVAL;
+			goto err_unlock;
+		}
+		r = 0;
+	}
+	if (r) {
+		pr_err("No fence found\n");
+		goto err_unlock;
+	}
+	dma_fence_signal(f);
+err_unlock:
+	dma_resv_unlock(&resv);
+err_free:
+	dma_resv_fini(&resv);
+	dma_fence_put(f);
+	return r;
+}
+
+static int test_excl_for_each(void *arg)
+{
+	return test_for_each(arg, false);
+}
+
+static int test_shared_for_each(void *arg)
+{
+	return test_for_each(arg, true);
+}
+
+static int test_for_each_unlocked(void *arg, bool shared)
+{
+	struct dma_resv_iter cursor;
+	struct dma_fence *f, *fence;
+	struct dma_resv resv;
+	int r;
+
+	f = alloc_fence();
+	if (!f)
+		return -ENOMEM;
+
+	dma_resv_init(&resv);
+	r = dma_resv_lock(&resv, NULL);
+	if (r) {
+		pr_err("Resv locking failed\n");
+		goto err_free;
+	}
+
+	if (shared) {
+		r = dma_resv_reserve_shared(&resv, 1);
+		if (r) {
+			pr_err("Resv shared slot allocation failed\n");
+			dma_resv_unlock(&resv);
+			goto err_free;
+		}
+
+		dma_resv_add_shared_fence(&resv, f);
+	} else {
+		dma_resv_add_excl_fence(&resv, f);
+	}
+	dma_resv_unlock(&resv);
+
+	r = -ENOENT;
+	dma_resv_iter_begin(&cursor, &resv, shared);
+	dma_resv_for_each_fence_unlocked(&cursor, fence) {
+		if (!r) {
+			pr_err("More than one fence found\n");
+			r = -EINVAL;
+			goto err_iter_end;
+		}
+		if (!dma_resv_iter_is_restarted(&cursor)) {
+			pr_err("No restart flag\n");
+			goto err_iter_end;
+		}
+		if (f != fence) {
+			pr_err("Unexpected fence\n");
+			r = -EINVAL;
+			goto err_iter_end;
+		}
+		if (dma_resv_iter_is_exclusive(&cursor) != !shared) {
+			pr_err("Unexpected fence usage\n");
+			r = -EINVAL;
+			goto err_iter_end;
+		}
+
+		/* We use r as state here */
+		if (r == -ENOENT) {
+			r = -EINVAL;
+			/* That should trigger an restart */
+			cursor.seq--;
+		} else if (r == -EINVAL) {
+			r = 0;
+		}
+	}
+	if (r)
+		pr_err("No fence found\n");
+err_iter_end:
+	dma_resv_iter_end(&cursor);
+	dma_fence_signal(f);
+err_free:
+	dma_resv_fini(&resv);
+	dma_fence_put(f);
+	return r;
+}
+
+static int test_excl_for_each_unlocked(void *arg)
+{
+	return test_for_each_unlocked(arg, false);
+}
+
+static int test_shared_for_each_unlocked(void *arg)
+{
+	return test_for_each_unlocked(arg, true);
+}
+
+static int test_get_fences(void *arg, bool shared)
+{
+	struct dma_fence *f, *excl = NULL, **fences = NULL;
+	struct dma_resv resv;
+	int r, i;
+
+	f = alloc_fence();
+	if (!f)
+		return -ENOMEM;
+
+	dma_resv_init(&resv);
+	r = dma_resv_lock(&resv, NULL);
+	if (r) {
+		pr_err("Resv locking failed\n");
+		goto err_free;
+	}
+
+	if (shared) {
+		r = dma_resv_reserve_shared(&resv, 1);
+		if (r) {
+			pr_err("Resv shared slot allocation failed\n");
+			dma_resv_unlock(&resv);
+			goto err_free;
+		}
+
+		dma_resv_add_shared_fence(&resv, f);
+	} else {
+		dma_resv_add_excl_fence(&resv, f);
+	}
+	dma_resv_unlock(&resv);
+
+	r = dma_resv_get_fences(&resv, &excl, &i, &fences);
+	if (r) {
+		pr_err("get_fences failed\n");
+		goto err_free;
+	}
+
+	if (shared) {
+		if (excl != NULL) {
+			pr_err("get_fences returned unexpected excl fence\n");
+			goto err_free;
+		}
+		if (i != 1 || fences[0] != f) {
+			pr_err("get_fences returned unexpected shared fence\n");
+			goto err_free;
+		}
+	} else {
+		if (excl != f) {
+			pr_err("get_fences returned unexpected excl fence\n");
+			goto err_free;
+		}
+		if (i != 0) {
+			pr_err("get_fences returned unexpected shared fence\n");
+			goto err_free;
+		}
+	}
+
+	dma_fence_signal(f);
+err_free:
+	dma_fence_put(excl);
+	while (i--)
+		dma_fence_put(fences[i]);
+	kfree(fences);
+	dma_resv_fini(&resv);
+	dma_fence_put(f);
+	return r;
+}
+
+static int test_excl_get_fences(void *arg)
+{
+	return test_get_fences(arg, false);
+}
+
+static int test_shared_get_fences(void *arg)
+{
+	return test_get_fences(arg, true);
+}
+
+int dma_resv(void)
+{
+	static const struct subtest tests[] = {
+		SUBTEST(sanitycheck),
+		SUBTEST(test_excl_signaling),
+		SUBTEST(test_shared_signaling),
+		SUBTEST(test_excl_for_each),
+		SUBTEST(test_shared_for_each),
+		SUBTEST(test_excl_for_each_unlocked),
+		SUBTEST(test_shared_for_each_unlocked),
+		SUBTEST(test_excl_get_fences),
+		SUBTEST(test_shared_get_fences),
+	};
+
+	spin_lock_init(&fence_lock);
+	return subtests(tests, NULL);
+}