/* 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_enable_sw_signaling(f);
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;
dma_fence_enable_sw_signaling(f);
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_enable_sw_signaling(f);
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;
dma_fence_enable_sw_signaling(f);
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_enable_sw_signaling(f);
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;
dma_fence_enable_sw_signaling(f);
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_on_stack(&wt.timer, wait_timer, 0);
wt.f = mock_fence();
if (!wt.f)
return -ENOMEM;
dma_fence_enable_sw_signaling(wt.f);
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 jiffy!\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);
destroy_timer_on_stack(&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;
}
dma_fence_enable_sw_signaling(f1);
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);
if (IS_ERR(t[i].task)) {
ret = PTR_ERR(t[i].task);
while (--i >= 0)
kthread_stop_put(t[i].task);
return ret;
}
get_task_struct(t[i].task);
}
msleep(50);
for (i = 0; i < ARRAY_SIZE(t); i++) {
int err;
err = kthread_stop_put(t[i].task);
if (err && !ret)
ret = err;
}
}
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)=%zu\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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