Commit 2989f645 authored by Chris Wilson's avatar Chris Wilson
Browse files

dma-buf: Add selftests for dma-fence 



Exercise the dma-fence API exported to drivers.

Signed-off-by: default avatarChris Wilson <chris@chris-wilson.co.uk>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Acked-by: default avatarDaniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20190819095928.32091-2-chris@chris-wilson.co.uk
parent 9536b64a

drivers/dma-buf/Makefile

+4 −1
Original line number Diff line number Diff line
@@ -5,5 +5,8 @@ obj-$(CONFIG_SYNC_FILE) += sync_file.o 
obj-$(CONFIG_SW_SYNC)		+= sw_sync.o sync_debug.o

obj-$(CONFIG_UDMABUF)		+= udmabuf.o



dmabuf_selftests-y := selftest.o

dmabuf_selftests-y := \

	selftest.o \

	st-dma-fence.o



obj-$(CONFIG_DMABUF_SELFTESTS)	+= dmabuf_selftests.o

drivers/dma-buf/selftests.h

+1 −0
Original line number Diff line number Diff line
@@ -10,3 +10,4 @@ 
 * Tests are executed in order by igt/dmabuf_selftest

 */

selftest(sanitycheck, __sanitycheck__) /* keep first (igt selfcheck) */

selftest(dma_fence, dma_fence)

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

0 → 100644
+573 −0
Original line number Diff line number Diff line 
/* SPDX-License-Identifier: MIT */



/*

 * Copyright © 2019 Intel Corporation

 */



#include <linux/delay.h>

#include <linux/dma-fence.h>

#include <linux/kernel.h>

#include <linux/kthread.h>

#include <linux/sched/signal.h>

#include <linux/slab.h>

#include <linux/spinlock.h>



#include "selftest.h"



static struct kmem_cache *slab_fences;



static struct mock_fence {

	struct dma_fence base;

	struct spinlock lock;

} *to_mock_fence(struct dma_fence *f) {

	return container_of(f, struct mock_fence, base);

}



static const char *mock_name(struct dma_fence *f)

{

	return "mock";

}



static void mock_fence_release(struct dma_fence *f)

{

	kmem_cache_free(slab_fences, to_mock_fence(f));

}



struct wait_cb {

	struct dma_fence_cb cb;

	struct task_struct *task;

};



static void mock_wakeup(struct dma_fence *f, struct dma_fence_cb *cb)

{

	wake_up_process(container_of(cb, struct wait_cb, cb)->task);

}



static long mock_wait(struct dma_fence *f, bool intr, long timeout)

{

	const int state = intr ? TASK_INTERRUPTIBLE : TASK_UNINTERRUPTIBLE;

	struct wait_cb cb = { .task = current };



	if (dma_fence_add_callback(f, &cb.cb, mock_wakeup))

		return timeout;



	while (timeout) {

		set_current_state(state);



		if (test_bit(DMA_FENCE_FLAG_SIGNALED_BIT, &f->flags))

			break;



		if (signal_pending_state(state, current))

			break;



		timeout = schedule_timeout(timeout);

	}

	__set_current_state(TASK_RUNNING);



	if (!dma_fence_remove_callback(f, &cb.cb))

		return timeout;



	if (signal_pending_state(state, current))

		return -ERESTARTSYS;



	return -ETIME;

}



static const struct dma_fence_ops mock_ops = {

	.get_driver_name = mock_name,

	.get_timeline_name = mock_name,

	.wait = mock_wait,

	.release = mock_fence_release,

};



static struct dma_fence *mock_fence(void)

{

	struct mock_fence *f;



	f = kmem_cache_alloc(slab_fences, GFP_KERNEL);

	if (!f)

		return NULL;



	spin_lock_init(&f->lock);

	dma_fence_init(&f->base, &mock_ops, &f->lock, 0, 0);



	return &f->base;

}



static int sanitycheck(void *arg)

{

	struct dma_fence *f;



	f = mock_fence();

	if (!f)

		return -ENOMEM;



	dma_fence_signal(f);

	dma_fence_put(f);



	return 0;

}



static int test_signaling(void *arg)

{

	struct dma_fence *f;

	int err = -EINVAL;



	f = mock_fence();

	if (!f)

		return -ENOMEM;



	if (dma_fence_is_signaled(f)) {

		pr_err("Fence unexpectedly signaled on creation\n");

		goto err_free;

	}



	if (dma_fence_signal(f)) {

		pr_err("Fence reported being already signaled\n");

		goto err_free;

	}



	if (!dma_fence_is_signaled(f)) {

		pr_err("Fence not reporting signaled\n");

		goto err_free;

	}



	if (!dma_fence_signal(f)) {

		pr_err("Fence reported not being already signaled\n");

		goto err_free;

	}



	err = 0;

err_free:

	dma_fence_put(f);

	return err;

}



struct simple_cb {

	struct dma_fence_cb cb;

	bool seen;

};



static void simple_callback(struct dma_fence *f, struct dma_fence_cb *cb)

{

	smp_store_mb(container_of(cb, struct simple_cb, cb)->seen, true);

}



static int test_add_callback(void *arg)

{

	struct simple_cb cb = {};

	struct dma_fence *f;

	int err = -EINVAL;



	f = mock_fence();

	if (!f)

		return -ENOMEM;



	if (dma_fence_add_callback(f, &cb.cb, simple_callback)) {

		pr_err("Failed to add callback, fence already signaled!\n");

		goto err_free;

	}



	dma_fence_signal(f);

	if (!cb.seen) {

		pr_err("Callback failed!\n");

		goto err_free;

	}



	err = 0;

err_free:

	dma_fence_put(f);

	return err;

}



static int test_late_add_callback(void *arg)

{

	struct simple_cb cb = {};

	struct dma_fence *f;

	int err = -EINVAL;



	f = mock_fence();

	if (!f)

		return -ENOMEM;



	dma_fence_signal(f);



	if (!dma_fence_add_callback(f, &cb.cb, simple_callback)) {

		pr_err("Added callback, but fence was already signaled!\n");

		goto err_free;

	}



	dma_fence_signal(f);

	if (cb.seen) {

		pr_err("Callback called after failed attachment !\n");

		goto err_free;

	}



	err = 0;

err_free:

	dma_fence_put(f);

	return err;

}



static int test_rm_callback(void *arg)

{

	struct simple_cb cb = {};

	struct dma_fence *f;

	int err = -EINVAL;



	f = mock_fence();

	if (!f)

		return -ENOMEM;



	if (dma_fence_add_callback(f, &cb.cb, simple_callback)) {

		pr_err("Failed to add callback, fence already signaled!\n");

		goto err_free;

	}



	if (!dma_fence_remove_callback(f, &cb.cb)) {

		pr_err("Failed to remove callback!\n");

		goto err_free;

	}



	dma_fence_signal(f);

	if (cb.seen) {

		pr_err("Callback still signaled after removal!\n");

		goto err_free;

	}



	err = 0;

err_free:

	dma_fence_put(f);

	return err;

}



static int test_late_rm_callback(void *arg)

{

	struct simple_cb cb = {};

	struct dma_fence *f;

	int err = -EINVAL;



	f = mock_fence();

	if (!f)

		return -ENOMEM;



	if (dma_fence_add_callback(f, &cb.cb, simple_callback)) {

		pr_err("Failed to add callback, fence already signaled!\n");

		goto err_free;

	}



	dma_fence_signal(f);

	if (!cb.seen) {

		pr_err("Callback failed!\n");

		goto err_free;

	}



	if (dma_fence_remove_callback(f, &cb.cb)) {

		pr_err("Callback removal succeed after being executed!\n");

		goto err_free;

	}



	err = 0;

err_free:

	dma_fence_put(f);

	return err;

}



static int test_status(void *arg)

{

	struct dma_fence *f;

	int err = -EINVAL;



	f = mock_fence();

	if (!f)

		return -ENOMEM;



	if (dma_fence_get_status(f)) {

		pr_err("Fence unexpectedly has signaled status on creation\n");

		goto err_free;

	}



	dma_fence_signal(f);

	if (!dma_fence_get_status(f)) {

		pr_err("Fence not reporting signaled status\n");

		goto err_free;

	}



	err = 0;

err_free:

	dma_fence_put(f);

	return err;

}



static int test_error(void *arg)

{

	struct dma_fence *f;

	int err = -EINVAL;



	f = mock_fence();

	if (!f)

		return -ENOMEM;



	dma_fence_set_error(f, -EIO);



	if (dma_fence_get_status(f)) {

		pr_err("Fence unexpectedly has error status before signal\n");

		goto err_free;

	}



	dma_fence_signal(f);

	if (dma_fence_get_status(f) != -EIO) {

		pr_err("Fence not reporting error status, got %d\n",

		       dma_fence_get_status(f));

		goto err_free;

	}



	err = 0;

err_free:

	dma_fence_put(f);

	return err;

}



static int test_wait(void *arg)

{

	struct dma_fence *f;

	int err = -EINVAL;



	f = mock_fence();

	if (!f)

		return -ENOMEM;



	if (dma_fence_wait_timeout(f, false, 0) != -ETIME) {

		pr_err("Wait reported complete before being signaled\n");

		goto err_free;

	}



	dma_fence_signal(f);



	if (dma_fence_wait_timeout(f, false, 0) != 0) {

		pr_err("Wait reported incomplete after being signaled\n");

		goto err_free;

	}



	err = 0;

err_free:

	dma_fence_signal(f);

	dma_fence_put(f);

	return err;

}



struct wait_timer {

	struct timer_list timer;

	struct dma_fence *f;

};



static void wait_timer(struct timer_list *timer)

{

	struct wait_timer *wt = from_timer(wt, timer, timer);



	dma_fence_signal(wt->f);

}



static int test_wait_timeout(void *arg)

{

	struct wait_timer wt;

	int err = -EINVAL;



	timer_setup(&wt.timer, wait_timer, 0);



	wt.f = mock_fence();

	if (!wt.f)

		return -ENOMEM;



	if (dma_fence_wait_timeout(wt.f, false, 1) != -ETIME) {

		pr_err("Wait reported complete before being signaled\n");

		goto err_free;

	}



	mod_timer(&wt.timer, jiffies + 1);



	if (dma_fence_wait_timeout(wt.f, false, 2) == -ETIME) {

		if (timer_pending(&wt.timer)) {

			pr_notice("Timer did not fire within the jiffie!\n");

			err = 0; /* not our fault! */

		} else {

			pr_err("Wait reported incomplete after timeout\n");

		}

		goto err_free;

	}



	err = 0;

err_free:

	del_timer_sync(&wt.timer);

	dma_fence_signal(wt.f);

	dma_fence_put(wt.f);

	return err;

}



static int test_stub(void *arg)

{

	struct dma_fence *f[64];

	int err = -EINVAL;

	int i;



	for (i = 0; i < ARRAY_SIZE(f); i++) {

		f[i] = dma_fence_get_stub();

		if (!dma_fence_is_signaled(f[i])) {

			pr_err("Obtained unsignaled stub fence!\n");

			goto err;

		}

	}



	err = 0;

err:

	while (i--)

		dma_fence_put(f[i]);

	return err;

}



/* Now off to the races! */



struct race_thread {

	struct dma_fence __rcu **fences;

	struct task_struct *task;

	bool before;

	int id;

};



static void __wait_for_callbacks(struct dma_fence *f)

{

	spin_lock_irq(f->lock);

	spin_unlock_irq(f->lock);

}



static int thread_signal_callback(void *arg)

{

	const struct race_thread *t = arg;

	unsigned long pass = 0;

	unsigned long miss = 0;

	int err = 0;



	while (!err && !kthread_should_stop()) {

		struct dma_fence *f1, *f2;

		struct simple_cb cb;



		f1 = mock_fence();

		if (!f1) {

			err = -ENOMEM;

			break;

		}



		rcu_assign_pointer(t->fences[t->id], f1);

		smp_wmb();



		rcu_read_lock();

		do {

			f2 = dma_fence_get_rcu_safe(&t->fences[!t->id]);

		} while (!f2 && !kthread_should_stop());

		rcu_read_unlock();



		if (t->before)

			dma_fence_signal(f1);



		smp_store_mb(cb.seen, false);

		if (!f2 || dma_fence_add_callback(f2, &cb.cb, simple_callback))

			miss++, cb.seen = true;



		if (!t->before)

			dma_fence_signal(f1);



		if (!cb.seen) {

			dma_fence_wait(f2, false);

			__wait_for_callbacks(f2);

		}



		if (!READ_ONCE(cb.seen)) {

			pr_err("Callback not seen on thread %d, pass %lu (%lu misses), signaling %s add_callback; fence signaled? %s\n",

			       t->id, pass, miss,

			       t->before ? "before" : "after",

			       dma_fence_is_signaled(f2) ? "yes" : "no");

			err = -EINVAL;

		}



		dma_fence_put(f2);



		rcu_assign_pointer(t->fences[t->id], NULL);

		smp_wmb();



		dma_fence_put(f1);



		pass++;

	}



	pr_info("%s[%d] completed %lu passes, %lu misses\n",

		__func__, t->id, pass, miss);

	return err;

}



static int race_signal_callback(void *arg)

{

	struct dma_fence __rcu *f[2] = {};

	int ret = 0;

	int pass;



	for (pass = 0; !ret && pass <= 1; pass++) {

		struct race_thread t[2];

		int i;



		for (i = 0; i < ARRAY_SIZE(t); i++) {

			t[i].fences = f;

			t[i].id = i;

			t[i].before = pass;

			t[i].task = kthread_run(thread_signal_callback, &t[i],

						"dma-fence:%d", i);

			get_task_struct(t[i].task);

		}



		msleep(50);



		for (i = 0; i < ARRAY_SIZE(t); i++) {

			int err;



			err = kthread_stop(t[i].task);

			if (err && !ret)

				ret = err;



			put_task_struct(t[i].task);

		}

	}



	return ret;

}



int dma_fence(void)

{

	static const struct subtest tests[] = {

		SUBTEST(sanitycheck),

		SUBTEST(test_signaling),

		SUBTEST(test_add_callback),

		SUBTEST(test_late_add_callback),

		SUBTEST(test_rm_callback),

		SUBTEST(test_late_rm_callback),

		SUBTEST(test_status),

		SUBTEST(test_error),

		SUBTEST(test_wait),

		SUBTEST(test_wait_timeout),

		SUBTEST(test_stub),

		SUBTEST(race_signal_callback),

	};

	int ret;



	pr_info("sizeof(dma_fence)=%lu\n", sizeof(struct dma_fence));



	slab_fences = KMEM_CACHE(mock_fence,

				 SLAB_TYPESAFE_BY_RCU |

				 SLAB_HWCACHE_ALIGN);

	if (!slab_fences)

		return -ENOMEM;



	ret = subtests(tests, NULL);



	kmem_cache_destroy(slab_fences);



	return ret;

}

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