Exercise the dma-fence API exported to drivers.
Signed-off-by: Chris Wilson chris@chris-wilson.co.uk Cc: Daniel Vetter daniel.vetter@ffwll.ch --- drivers/dma-buf/Makefile | 5 +- drivers/dma-buf/selftests.h | 1 + drivers/dma-buf/st-dma-fence.c | 571 +++++++++++++++++++++++++++++++++ 3 files changed, 576 insertions(+), 1 deletion(-) create mode 100644 drivers/dma-buf/st-dma-fence.c
diff --git a/drivers/dma-buf/Makefile b/drivers/dma-buf/Makefile index b5ae122a9349..03479da06422 100644 --- a/drivers/dma-buf/Makefile +++ b/drivers/dma-buf/Makefile @@ -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 diff --git a/drivers/dma-buf/selftests.h b/drivers/dma-buf/selftests.h index 44b44390d23a..5320386f02e5 100644 --- a/drivers/dma-buf/selftests.h +++ b/drivers/dma-buf/selftests.h @@ -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) diff --git a/drivers/dma-buf/st-dma-fence.c b/drivers/dma-buf/st-dma-fence.c new file mode 100644 index 000000000000..a365dc7440e5 --- /dev/null +++ b/drivers/dma-buf/st-dma-fence.c @@ -0,0 +1,571 @@ +/* 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); + + ret = subtests(tests, NULL); + + kmem_cache_destroy(slab_fences); + + return ret; +}