On 20/04/03 10:12, Chris Wilson wrote:
> A few very simple testcases to exercise the dma-fence-chain API.
>
> Signed-off-by: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
> ---
> drivers/dma-buf/Makefile | 3 +-
> drivers/dma-buf/selftests.h | 1 +
> drivers/dma-buf/st-dma-fence-chain.c | 713 +++++++++++++++++++++++++++
> 3 files changed, 716 insertions(+), 1 deletion(-)
> create mode 100644 drivers/dma-buf/st-dma-fence-chain.c
>
> diff --git a/drivers/dma-buf/Makefile b/drivers/dma-buf/Makefile
> index 9c190026bfab..995e05f609ff 100644
> --- a/drivers/dma-buf/Makefile
> +++ b/drivers/dma-buf/Makefile
> @@ -9,6 +9,7 @@ obj-$(CONFIG_UDMABUF) += udmabuf.o
>
> dmabuf_selftests-y := \
> selftest.o \
> - st-dma-fence.o
> + st-dma-fence.o \
> + st-dma-fence-chain.o
>
> obj-$(CONFIG_DMABUF_SELFTESTS) += dmabuf_selftests.o
> diff --git a/drivers/dma-buf/selftests.h b/drivers/dma-buf/selftests.h
> index 5320386f02e5..55918ef9adab 100644
> --- a/drivers/dma-buf/selftests.h
> +++ b/drivers/dma-buf/selftests.h
> @@ -11,3 +11,4 @@
> */
> selftest(sanitycheck, __sanitycheck__) /* keep first (igt selfcheck) */
> selftest(dma_fence, dma_fence)
> +selftest(dma_fence_chain, dma_fence_chain)
> diff --git a/drivers/dma-buf/st-dma-fence-chain.c b/drivers/dma-buf/st-dma-fence-chain.c
> new file mode 100644
> index 000000000000..bd08ba67b03b
> --- /dev/null
> +++ b/drivers/dma-buf/st-dma-fence-chain.c
> @@ -0,0 +1,713 @@
> +// SPDX-License-Identifier: MIT
> +
> +/*
> + * Copyright © 2019 Intel Corporation
> + */
> +
> +#include <linux/delay.h>
> +#include <linux/dma-fence.h>
> +#include <linux/dma-fence-chain.h>
> +#include <linux/kernel.h>
> +#include <linux/kthread.h>
> +#include <linux/mm.h>
> +#include <linux/sched/signal.h>
> +#include <linux/slab.h>
> +#include <linux/spinlock.h>
> +#include <linux/random.h>
> +
> +#include "selftest.h"
> +
> +static struct kmem_cache *slab_fences;
> +
> +static inline struct mock_fence {
> + struct dma_fence base;
> + spinlock_t 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));
> +}
> +
> +static const struct dma_fence_ops mock_ops = {
> + .get_driver_name = mock_name,
> + .get_timeline_name = mock_name,
> + .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 inline struct mock_chain {
> + struct dma_fence_chain base;
> +} *to_mock_chain(struct dma_fence *f) {
> + return container_of(f, struct mock_chain, base.base);
> +}
> +
> +static struct dma_fence *mock_chain(struct dma_fence *prev,
> + struct dma_fence *fence,
> + u64 seqno)
> +{
> + struct mock_chain *f;
> +
> + f = kmalloc(sizeof(*f), GFP_KERNEL);
> + if (!f)
> + return NULL;
> +
> + dma_fence_chain_init(&f->base,
> + dma_fence_get(prev),
> + dma_fence_get(fence),
> + seqno);
> +
> + return &f->base.base;
> +}
> +
> +static int sanitycheck(void *arg)
> +{
> + struct dma_fence *f, *chain;
> + int err = 0;
> +
> + f = mock_fence();
> + if (!f)
> + return -ENOMEM;
> +
> + chain = mock_chain(NULL, f, 1);
> + if (!chain)
> + err = -ENOMEM;
> +
> + dma_fence_signal(f);
> + dma_fence_put(f);
> +
> + dma_fence_put(chain);
> +
> + return err;
> +}
> +
> +struct fence_chains {
> + unsigned int chain_length;
> + struct dma_fence **fences;
> + struct dma_fence **chains;
> +
> + struct dma_fence *tail;
> +};
> +
> +static uint64_t seqno_inc(unsigned int i)
> +{
> + return i + 1;
> +}
> +
> +static int fence_chains_init(struct fence_chains *fc, unsigned int count,
> + uint64_t (*seqno_fn)(unsigned int))
> +{
> + unsigned int i;
> + int err = 0;
> +
> + fc->chains = kvmalloc_array(count, sizeof(*fc->chains),
> + GFP_KERNEL | __GFP_ZERO);
> + if (!fc->chains)
> + return -ENOMEM;
> +
> + fc->fences = kvmalloc_array(count, sizeof(*fc->fences),
> + GFP_KERNEL | __GFP_ZERO);
> + if (!fc->fences) {
> + err = -ENOMEM;
> + goto err_chains;
> + }
> +
> + fc->tail = NULL;
> + for (i = 0; i < count; i++) {
> + fc->fences[i] = mock_fence();
> + if (!fc->fences[i]) {
> + err = -ENOMEM;
> + goto unwind;
> + }
> +
> + fc->chains[i] = mock_chain(fc->tail,
> + fc->fences[i],
> + seqno_fn(i));
> + if (!fc->chains[i]) {
> + err = -ENOMEM;
> + goto unwind;
> + }
> +
> + fc->tail = fc->chains[i];
> + }
> +
> + fc->chain_length = i;
> + return 0;
> +
> +unwind:
> + for (i = 0; i < count; i++) {
> + dma_fence_put(fc->fences[i]);
> + dma_fence_put(fc->chains[i]);
> + }
> + kvfree(fc->fences);
> +err_chains:
> + kvfree(fc->chains);
> + return err;
> +}
> +
> +static void fence_chains_fini(struct fence_chains *fc)
> +{
> + unsigned int i;
> +
> + for (i = 0; i < fc->chain_length; i++) {
> + dma_fence_signal(fc->fences[i]);
> + dma_fence_put(fc->fences[i]);
> + }
> + kvfree(fc->fences);
> +
> + for (i = 0; i < fc->chain_length; i++)
> + dma_fence_put(fc->chains[i]);
> + kvfree(fc->chains);
> +}
> +
> +static int find_seqno(void *arg)
> +{
> + struct fence_chains fc;
> + struct dma_fence *fence;
> + int err;
> + int i;
> +
> + err = fence_chains_init(&fc, 64, seqno_inc);
> + if (err)
> + return err;
> +
> + fence = dma_fence_get(fc.tail);
> + err = dma_fence_chain_find_seqno(&fence, 0);
> + dma_fence_put(fence);
> + if (err) {
> + pr_err("Reported %d for find_seqno(0)!\n", err);
> + goto err;
> + }
> +
> + for (i = 0; i < fc.chain_length; i++) {
> + fence = dma_fence_get(fc.tail);
> + err = dma_fence_chain_find_seqno(&fence, i + 1);
> + dma_fence_put(fence);
> + if (err) {
> + pr_err("Reported %d for find_seqno(%d:%d)!\n",
> + err, fc.chain_length + 1, i + 1);
> + goto err;
> + }
> + if (fence != fc.chains[i]) {
> + pr_err("Incorrect fence reported by find_seqno(%d:%d)\n",
> + fc.chain_length + 1, i + 1);
> + err = -EINVAL;
> + goto err;
> + }
> +
> + dma_fence_get(fence);
> + err = dma_fence_chain_find_seqno(&fence, i + 1);
> + dma_fence_put(fence);
> + if (err) {
> + pr_err("Error reported for finding self\n");
> + goto err;
> + }
> + if (fence != fc.chains[i]) {
> + pr_err("Incorrect fence reported by find self\n");
> + err = -EINVAL;
> + goto err;
> + }
> +
> + dma_fence_get(fence);
> + err = dma_fence_chain_find_seqno(&fence, i + 2);
> + dma_fence_put(fence);
> + if (!err) {
> + pr_err("Error not reported for future fence: find_seqno(%d:%d)!\n",
> + i + 1, i + 2);
> + err = -EINVAL;
> + goto err;
> + }
> +
> + dma_fence_get(fence);
> + err = dma_fence_chain_find_seqno(&fence, i);
> + dma_fence_put(fence);
> + if (err) {
> + pr_err("Error reported for previous fence!\n");
> + goto err;
> + }
> + if (i > 0 && fence != fc.chains[i - 1]) {
> + pr_err("Incorrect fence reported by find_seqno(%d:%d)\n",
> + i + 1, i);
> + err = -EINVAL;
> + goto err;
> + }
> + }
> +
> +err:
> + fence_chains_fini(&fc);
> + return err;
> +}
> +
> +static int find_signaled(void *arg)
> +{
> + struct fence_chains fc;
> + struct dma_fence *fence;
> + int err;
> +
> + err = fence_chains_init(&fc, 2, seqno_inc);
> + if (err)
> + return err;
> +
> + dma_fence_signal(fc.fences[0]);
> +
> + fence = dma_fence_get(fc.tail);
> + err = dma_fence_chain_find_seqno(&fence, 1);
> + dma_fence_put(fence);
> + if (err) {
> + pr_err("Reported %d for find_seqno()!\n", err);
> + goto err;
> + }
> +
> + if (fence && fence != fc.chains[0]) {
> + pr_err("Incorrect chain-fence.seqno:%lld reported for completed seqno:1\n",
> + fence->seqno);
> +
> + dma_fence_get(fence);
> + err = dma_fence_chain_find_seqno(&fence, 1);
> + dma_fence_put(fence);
> + if (err)
> + pr_err("Reported %d for finding self!\n", err);
> +
> + err = -EINVAL;
> + }
> +
> +err:
> + fence_chains_fini(&fc);
> + return err;
> +}
> +
> +static int find_out_of_order(void *arg)
> +{
> + struct fence_chains fc;
> + struct dma_fence *fence;
> + int err;
> +
> + err = fence_chains_init(&fc, 3, seqno_inc);
> + if (err)
> + return err;
> +
> + dma_fence_signal(fc.fences[1]);
> +
> + fence = dma_fence_get(fc.tail);
> + err = dma_fence_chain_find_seqno(&fence, 2);
> + dma_fence_put(fence);
> + if (err) {
> + pr_err("Reported %d for find_seqno()!\n", err);
> + goto err;
> + }
> +
> + if (fence && fence != fc.chains[1]) {
> + pr_err("Incorrect chain-fence.seqno:%lld reported for completed seqno:2\n",
> + fence->seqno);
> +
> + dma_fence_get(fence);
> + err = dma_fence_chain_find_seqno(&fence, 2);
> + dma_fence_put(fence);
> + if (err)
> + pr_err("Reported %d for finding self!\n", err);
> +
> + err = -EINVAL;
> + }
> +
> +err:
> + fence_chains_fini(&fc);
> + return err;
> +}
> +
> +static uint64_t seqno_inc2(unsigned int i)
> +{
> + return 2 * i + 2;
> +}
> +
> +static int find_gap(void *arg)
> +{
> + struct fence_chains fc;
> + struct dma_fence *fence;
> + int err;
> + int i;
> +
> + err = fence_chains_init(&fc, 64, seqno_inc2);
> + if (err)
> + return err;
> +
> + for (i = 0; i < fc.chain_length; i++) {
> + fence = dma_fence_get(fc.tail);
> + err = dma_fence_chain_find_seqno(&fence, 2 * i + 1);
> + dma_fence_put(fence);
> + if (err) {
> + pr_err("Reported %d for find_seqno(%d:%d)!\n",
> + err, fc.chain_length + 1, 2 * i + 1);
> + goto err;
> + }
> + if (fence != fc.chains[i]) {
> + pr_err("Incorrect fence.seqno:%lld reported by find_seqno(%d:%d)\n",
> + fence->seqno,
> + fc.chain_length + 1,
> + 2 * i + 1);
> + err = -EINVAL;
> + goto err;
> + }
> +
> + dma_fence_get(fence);
> + err = dma_fence_chain_find_seqno(&fence, 2 * i + 2);
> + dma_fence_put(fence);
> + if (err) {
> + pr_err("Error reported for finding self\n");
> + goto err;
> + }
> + if (fence != fc.chains[i]) {
> + pr_err("Incorrect fence reported by find self\n");
> + err = -EINVAL;
> + goto err;
> + }
> + }
> +
> +err:
> + fence_chains_fini(&fc);
> + return err;
> +}
> +
> +struct find_race {
> + struct fence_chains fc;
> + atomic_t children;
> +};
> +
> +static int __find_race(void *arg)
> +{
> + struct find_race *data = arg;
> + int err = 0;
> +
> + while (!kthread_should_stop()) {
> + struct dma_fence *fence = dma_fence_get(data->fc.tail);
> + int seqno;
> +
> + seqno = prandom_u32_max(data->fc.chain_length) + 1;
> +
> + err = dma_fence_chain_find_seqno(&fence, seqno);
> + if (err) {
> + pr_err("Failed to find fence seqno:%d\n",
> + seqno);
> + dma_fence_put(fence);
> + break;
> + }
> + if (!fence)
> + goto signal;
> +
> + err = dma_fence_chain_find_seqno(&fence, seqno);
> + if (err) {
> + pr_err("Reported an invalid fence for find-self:%d\n",
> + seqno);
> + dma_fence_put(fence);
> + break;
> + }
> +
> + if (fence->seqno < seqno) {
> + pr_err("Reported an earlier fence.seqno:%lld for seqno:%d\n",
> + fence->seqno, seqno);
> + err = -EINVAL;
> + dma_fence_put(fence);
> + break;
> + }
> +
> + dma_fence_put(fence);
> +
> +signal:
> + seqno = prandom_u32_max(data->fc.chain_length - 1);
> + dma_fence_signal(data->fc.fences[seqno]);
> + cond_resched();
> + }
> +
> + if (atomic_dec_and_test(&data->children))
> + wake_up_var(&data->children);
> + return err;
> +}
> +
> +static int find_race(void *arg)
> +{
> + struct find_race data;
> + int ncpus = num_online_cpus();
> + struct task_struct **threads;
> + unsigned long count;
> + int err;
> + int i;
> +
> + err = fence_chains_init(&data.fc, 64 << 10, seqno_inc);
> + if (err)
> + return err;
> +
> + threads = kmalloc_array(ncpus, sizeof(*threads), GFP_KERNEL);
> + if (!threads) {
> + err = -ENOMEM;
> + goto err;
> + }
> +
> + atomic_set(&data.children, 0);
> + for (i = 0; i < ncpus; i++) {
> + threads[i] = kthread_run(__find_race, &data, "dmabuf/%d", i);
> + if (IS_ERR(threads[i])) {
> + ncpus = i;
> + break;
> + }
> + atomic_inc(&data.children);
> + get_task_struct(threads[i]);
> + }
> +
> + wait_var_event_timeout(&data.children,
> + !atomic_read(&data.children),
> + 5 * HZ);
> +
> + for (i = 0; i < ncpus; i++) {
> + int ret;
> +
> + ret = kthread_stop(threads[i]);
> + if (ret && !err)
> + err = ret;
> + put_task_struct(threads[i]);
> + }
> + kfree(threads);
> +
> + count = 0;
> + for (i = 0; i < data.fc.chain_length; i++)
> + if (dma_fence_is_signaled(data.fc.fences[i]))
> + count++;
> + pr_info("Completed %lu cycles\n", count);
> +
> +err:
> + fence_chains_fini(&data.fc);
> + return err;
> +}
> +
> +static int signal_forward(void *arg)
> +{
> + struct fence_chains fc;
> + int err;
> + int i;
> +
> + err = fence_chains_init(&fc, 64, seqno_inc);
> + if (err)
> + return err;
> +
> + for (i = 0; i < fc.chain_length; i++) {
> + dma_fence_signal(fc.fences[i]);
> +
> + if (!dma_fence_is_signaled(fc.chains[i])) {
> + pr_err("chain[%d] not signaled!\n", i);
> + err = -EINVAL;
> + goto err;
> + }
> +
> + if (i + 1 < fc.chain_length &&
> + dma_fence_is_signaled(fc.chains[i + 1])) {
> + pr_err("chain[%d] is signaled!\n", i);
> + err = -EINVAL;
> + goto err;
> + }
> + }
> +
> +err:
> + fence_chains_fini(&fc);
> + return err;
> +}
> +
> +static int signal_backward(void *arg)
> +{
> + struct fence_chains fc;
> + int err;
> + int i;
> +
> + err = fence_chains_init(&fc, 64, seqno_inc);
> + if (err)
> + return err;
> +
> + for (i = fc.chain_length; i--; ) {
> + dma_fence_signal(fc.fences[i]);
> +
> + if (i > 0 && dma_fence_is_signaled(fc.chains[i])) {
> + pr_err("chain[%d] is signaled!\n", i);
> + err = -EINVAL;
> + goto err;
> + }
> + }
> +
> + for (i = 0; i < fc.chain_length; i++) {
> + if (!dma_fence_is_signaled(fc.chains[i])) {
> + pr_err("chain[%d] was not signaled!\n", i);
> + err = -EINVAL;
> + goto err;
> + }
> + }
> +
> +err:
> + fence_chains_fini(&fc);
> + return err;
> +}
> +
> +static int __wait_fence_chains(void *arg)
> +{
> + struct fence_chains *fc = arg;
> +
> + if (dma_fence_wait(fc->tail, false))
> + return -EIO;
> +
> + return 0;
> +}
> +
> +static int wait_forward(void *arg)
> +{
> + struct fence_chains fc;
> + struct task_struct *tsk;
> + int err;
> + int i;
> +
> + err = fence_chains_init(&fc, 64 << 10, seqno_inc);
> + if (err)
> + return err;
> +
> + tsk = kthread_run(__wait_fence_chains, &fc, "dmabuf/wait");
> + if (IS_ERR(tsk)) {
> + err = PTR_ERR(tsk);
> + goto err;
> + }
> + get_task_struct(tsk);
> + yield_to(tsk, true);
> +
> + for (i = 0; i < fc.chain_length; i++)
> + dma_fence_signal(fc.fences[i]);
> +
> + err = kthread_stop(tsk);
> + put_task_struct(tsk);
> +
> +err:
> + fence_chains_fini(&fc);
> + return err;
> +}
> +
> +static int wait_backward(void *arg)
> +{
> + struct fence_chains fc;
> + struct task_struct *tsk;
> + int err;
> + int i;
> +
> + err = fence_chains_init(&fc, 64 << 10, seqno_inc);
> + if (err)
> + return err;
> +
> + tsk = kthread_run(__wait_fence_chains, &fc, "dmabuf/wait");
> + if (IS_ERR(tsk)) {
> + err = PTR_ERR(tsk);
> + goto err;
> + }
> + get_task_struct(tsk);
> + yield_to(tsk, true);
> +
> + for (i = fc.chain_length; i--; )
> + dma_fence_signal(fc.fences[i]);
> +
> + err = kthread_stop(tsk);
> + put_task_struct(tsk);
> +
> +err:
> + fence_chains_fini(&fc);
> + return err;
> +}
> +
> +static void randomise_fences(struct fence_chains *fc)
> +{
> + unsigned int count = fc->chain_length;
> +
> + /* Fisher-Yates shuffle courtesy of Knuth */
> + while (--count) {
> + unsigned int swp;
> +
> + swp = prandom_u32_max(count + 1);
> + if (swp == count)
> + continue;
> +
> + swap(fc->fences[count], fc->fences[swp]);
> + }
> +}
> +
> +static int wait_random(void *arg)
> +{
> + struct fence_chains fc;
> + struct task_struct *tsk;
> + int err;
> + int i;
> +
> + err = fence_chains_init(&fc, 64 << 10, seqno_inc);
> + if (err)
> + return err;
> +
> + randomise_fences(&fc);
> +
> + tsk = kthread_run(__wait_fence_chains, &fc, "dmabuf/wait");
> + if (IS_ERR(tsk)) {
> + err = PTR_ERR(tsk);
> + goto err;
> + }
> + get_task_struct(tsk);
> + yield_to(tsk, true);
> +
> + for (i = 0; i < fc.chain_length; i++)
> + dma_fence_signal(fc.fences[i]);
> +
> + err = kthread_stop(tsk);
> + put_task_struct(tsk);
> +
> +err:
> + fence_chains_fini(&fc);
> + return err;
> +}
> +
> +int dma_fence_chain(void)
> +{
> + static const struct subtest tests[] = {
> + SUBTEST(sanitycheck),
> + SUBTEST(find_seqno),
> + SUBTEST(find_signaled),
> + SUBTEST(find_out_of_order),
> + SUBTEST(find_gap),
> + SUBTEST(find_race),
> + SUBTEST(signal_forward),
> + SUBTEST(signal_backward),
> + SUBTEST(wait_forward),
> + SUBTEST(wait_backward),
> + SUBTEST(wait_random),
> + };
> + int ret;
> +
> + pr_info("sizeof(dma_fence_chain)=%zu\n",
> + sizeof(struct dma_fence_chain));
> +
> + 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;
> +}
I think it covers all api required for fence-chain.
Reviewed-by: Venkata Sandeep Dhanalakota <venkata.s.dhanalakota@xxxxxxxxx>
> --
> 2.20.1
>
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