A few very simple testcases to exercise the dma-fence-chain API.
Signed-off-by: Chris Wilson chris@chris-wilson.co.uk Reviewed-by: Venkata Sandeep Dhanalakota venkata.s.dhanalakota@intel.com --- 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; +}