[PATCH 1/2] dma-buf: add dma_fence_unwrap
Christian König
christian.koenig at amd.com
Mon Mar 21 10:31:41 UTC 2022
[Adding Daniel]
Just once more a ping for this.
It's an important bug fix and the end user already reported that it works.
Regards,
Christian.
Am 14.03.22 um 12:14 schrieb Christian König:
> Just a gentle ping.
>
> This series is an important fix for drm-misc-next-fixes.
>
> Regards,
> Christian.
>
> Am 11.03.22 um 12:02 schrieb Christian König:
>> Add a general purpose helper to deep dive into
>> dma_fence_chain/dma_fence_array
>> structures and iterate over all the fences in them.
>>
>> This is useful when we need to flatten out all fences in those
>> structures.
>>
>> Signed-off-by: Christian König <christian.koenig at amd.com>
>> ---
>> Documentation/driver-api/dma-buf.rst | 6 +
>> drivers/dma-buf/Makefile | 1 +
>> drivers/dma-buf/selftests.h | 1 +
>> drivers/dma-buf/st-dma-fence-unwrap.c | 279 ++++++++++++++++++++++++++
>> include/linux/dma-fence-unwrap.h | 99 +++++++++
>> 5 files changed, 386 insertions(+)
>> create mode 100644 drivers/dma-buf/st-dma-fence-unwrap.c
>> create mode 100644 include/linux/dma-fence-unwrap.h
>>
>> diff --git a/Documentation/driver-api/dma-buf.rst
>> b/Documentation/driver-api/dma-buf.rst
>> index 2cd7db82d9fe..7209500f08c8 100644
>> --- a/Documentation/driver-api/dma-buf.rst
>> +++ b/Documentation/driver-api/dma-buf.rst
>> @@ -194,6 +194,12 @@ DMA Fence Chain
>> .. kernel-doc:: include/linux/dma-fence-chain.h
>> :internal:
>> +DMA Fence unwrap
>> +~~~~~~~~~~~~~~~~
>> +
>> +.. kernel-doc:: include/linux/dma-fence-unwrap.h
>> + :internal:
>> +
>> DMA Fence uABI/Sync File
>> ~~~~~~~~~~~~~~~~~~~~~~~~
>> diff --git a/drivers/dma-buf/Makefile b/drivers/dma-buf/Makefile
>> index 511805dbeb75..4c9eb53ba3f8 100644
>> --- a/drivers/dma-buf/Makefile
>> +++ b/drivers/dma-buf/Makefile
>> @@ -12,6 +12,7 @@ dmabuf_selftests-y := \
>> selftest.o \
>> st-dma-fence.o \
>> st-dma-fence-chain.o \
>> + st-dma-fence-unwrap.o \
>> st-dma-resv.o
>> obj-$(CONFIG_DMABUF_SELFTESTS) += dmabuf_selftests.o
>> diff --git a/drivers/dma-buf/selftests.h b/drivers/dma-buf/selftests.h
>> index 97d73aaa31da..851965867d9c 100644
>> --- a/drivers/dma-buf/selftests.h
>> +++ b/drivers/dma-buf/selftests.h
>> @@ -12,4 +12,5 @@
>> selftest(sanitycheck, __sanitycheck__) /* keep first (igt
>> selfcheck) */
>> selftest(dma_fence, dma_fence)
>> selftest(dma_fence_chain, dma_fence_chain)
>> +selftest(dma_fence_unwrap, dma_fence_unwrap)
>> selftest(dma_resv, dma_resv)
>> diff --git a/drivers/dma-buf/st-dma-fence-unwrap.c
>> b/drivers/dma-buf/st-dma-fence-unwrap.c
>> new file mode 100644
>> index 000000000000..d821faaebe93
>> --- /dev/null
>> +++ b/drivers/dma-buf/st-dma-fence-unwrap.c
>> @@ -0,0 +1,279 @@
>> +// SPDX-License-Identifier: MIT
>> +
>> +/*
>> + * Copyright (C) 2022 Advanced Micro Devices, Inc.
>> + */
>> +
>> +#include <linux/dma-fence-unwrap.h>
>> +#if 0
>> +#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>
>> +#endif
>> +
>> +#include "selftest.h"
>> +
>> +#define CHAIN_SZ (4 << 10)
>> +
>> +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 struct dma_fence *mock_array(unsigned int num_fences, ...)
>> +{
>> + struct dma_fence_array *array;
>> + struct dma_fence **fences;
>> + va_list valist;
>> + int i;
>> +
>> + fences = kcalloc(num_fences, sizeof(*fences), GFP_KERNEL);
>> + if (!fences)
>> + return NULL;
>> +
>> + va_start(valist, num_fences);
>> + for (i = 0; i < num_fences; ++i)
>> + fences[i] = va_arg(valist, typeof(*fences));
>> + va_end(valist);
>> +
>> + array = dma_fence_array_create(num_fences, fences,
>> + dma_fence_context_alloc(1),
>> + 1, false);
>> + if (!array)
>> + goto cleanup;
>> + return &array->base;
>> +
>> +cleanup:
>> + for (i = 0; i < num_fences; ++i)
>> + dma_fence_put(fences[i]);
>> + kfree(fences);
>> + return NULL;
>> +}
>> +
>> +static struct dma_fence *mock_chain(struct dma_fence *prev,
>> + struct dma_fence *fence)
>> +{
>> + struct dma_fence_chain *f;
>> +
>> + f = dma_fence_chain_alloc();
>> + if (!f) {
>> + dma_fence_put(prev);
>> + dma_fence_put(fence);
>> + return NULL;
>> + }
>> +
>> + dma_fence_chain_init(f, prev, fence, 1);
>> + return &f->base;
>> +}
>> +
>> +static int sanitycheck(void *arg)
>> +{
>> + struct dma_fence *f, *chain, *array;
>> + int err = 0;
>> +
>> + f = mock_fence();
>> + if (!f)
>> + return -ENOMEM;
>> +
>> + array = mock_array(1, f);
>> + if (!array)
>> + return -ENOMEM;
>> +
>> + chain = mock_chain(NULL, array);
>> + if (!chain)
>> + return -ENOMEM;
>> +
>> + dma_fence_signal(f);
>> + dma_fence_put(chain);
>> + return err;
>> +}
>> +
>> +static int unwrap_array(void *arg)
>> +{
>> + struct dma_fence *fence, *f1, *f2, *array;
>> + struct dma_fence_unwrap iter;
>> + int err = 0;
>> +
>> + f1 = mock_fence();
>> + if (!f1)
>> + return -ENOMEM;
>> +
>> + f2 = mock_fence();
>> + if (!f2) {
>> + dma_fence_put(f1);
>> + return -ENOMEM;
>> + }
>> +
>> + array = mock_array(2, f1, f2);
>> + if (!array)
>> + return -ENOMEM;
>> +
>> + dma_fence_unwrap_for_each(fence, &iter, array) {
>> + if (fence == f1) {
>> + f1 = NULL;
>> + } else if (fence == f2) {
>> + f2 = NULL;
>> + } else {
>> + pr_err("Unexpected fence!\n");
>> + err = -EINVAL;
>> + }
>> + }
>> +
>> + if (f1 || f2) {
>> + pr_err("Not all fences seen!\n");
>> + err = -EINVAL;
>> + }
>> +
>> + dma_fence_signal(f1);
>> + dma_fence_signal(f2);
>> + dma_fence_put(array);
>> + return 0;
>> +}
>> +
>> +static int unwrap_chain(void *arg)
>> +{
>> + struct dma_fence *fence, *f1, *f2, *chain;
>> + struct dma_fence_unwrap iter;
>> + int err = 0;
>> +
>> + f1 = mock_fence();
>> + if (!f1)
>> + return -ENOMEM;
>> +
>> + f2 = mock_fence();
>> + if (!f2) {
>> + dma_fence_put(f1);
>> + return -ENOMEM;
>> + }
>> +
>> + chain = mock_chain(f1, f2);
>> + if (!chain)
>> + return -ENOMEM;
>> +
>> + dma_fence_unwrap_for_each(fence, &iter, chain) {
>> + if (fence == f1) {
>> + f1 = NULL;
>> + } else if (fence == f2) {
>> + f2 = NULL;
>> + } else {
>> + pr_err("Unexpected fence!\n");
>> + err = -EINVAL;
>> + }
>> + }
>> +
>> + if (f1 || f2) {
>> + pr_err("Not all fences seen!\n");
>> + err = -EINVAL;
>> + }
>> +
>> + dma_fence_signal(f1);
>> + dma_fence_signal(f2);
>> + dma_fence_put(chain);
>> + return 0;
>> +}
>> +
>> +static int unwrap_chain_array(void *arg)
>> +{
>> + struct dma_fence *fence, *f1, *f2, *array, *chain;
>> + struct dma_fence_unwrap iter;
>> + int err = 0;
>> +
>> + f1 = mock_fence();
>> + if (!f1)
>> + return -ENOMEM;
>> +
>> + f2 = mock_fence();
>> + if (!f2) {
>> + dma_fence_put(f1);
>> + return -ENOMEM;
>> + }
>> +
>> + array = mock_array(2, f1, f2);
>> + if (!array)
>> + return -ENOMEM;
>> +
>> + chain = mock_chain(NULL, array);
>> + if (!chain)
>> + return -ENOMEM;
>> +
>> + dma_fence_unwrap_for_each(fence, &iter, chain) {
>> + if (fence == f1) {
>> + f1 = NULL;
>> + } else if (fence == f2) {
>> + f2 = NULL;
>> + } else {
>> + pr_err("Unexpected fence!\n");
>> + err = -EINVAL;
>> + }
>> + }
>> +
>> + if (f1 || f2) {
>> + pr_err("Not all fences seen!\n");
>> + err = -EINVAL;
>> + }
>> +
>> + dma_fence_signal(f1);
>> + dma_fence_signal(f2);
>> + dma_fence_put(chain);
>> + return 0;
>> +}
>> +
>> +int dma_fence_unwrap(void)
>> +{
>> + static const struct subtest tests[] = {
>> + SUBTEST(sanitycheck),
>> + SUBTEST(unwrap_array),
>> + SUBTEST(unwrap_chain),
>> + SUBTEST(unwrap_chain_array),
>> + };
>> + int ret;
>> +
>> + 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;
>> +}
>> diff --git a/include/linux/dma-fence-unwrap.h
>> b/include/linux/dma-fence-unwrap.h
>> new file mode 100644
>> index 000000000000..54963df00c98
>> --- /dev/null
>> +++ b/include/linux/dma-fence-unwrap.h
>> @@ -0,0 +1,99 @@
>> +/* SPDX-License-Identifier: GPL-2.0-only */
>> +/*
>> + * fence-chain: chain fences together in a timeline
>> + *
>> + * Copyright (C) 2022 Advanced Micro Devices, Inc.
>> + * Authors:
>> + * Christian König <christian.koenig at amd.com>
>> + */
>> +
>> +#ifndef __LINUX_DMA_FENCE_UNWRAP_H
>> +#define __LINUX_DMA_FENCE_UNWRAP_H
>> +
>> +#include <linux/dma-fence-chain.h>
>> +#include <linux/dma-fence-array.h>
>> +
>> +/**
>> + * struct dma_fence_unwrap - cursor into the container structure
>> + */
>> +struct dma_fence_unwrap {
>> + /**
>> + * @chain: potential dma_fence_chain, but can be other fence as
>> well
>> + */
>> + struct dma_fence *chain;
>> + /**
>> + * @array: potential dma_fence_array, but can be other fence as
>> well
>> + */
>> + struct dma_fence *array;
>> + /**
>> + * @index: last returned index if @array is really a
>> dma_fence_array
>> + */
>> + unsigned int index;
>> +};
>> +
>> +/**
>> + * dma_fence_unwrap_array - helper to unwrap dma_fence_arrays
>> + * @cursor: cursor to initialize
>> + *
>> + * Helper function to unwrap dma_fence_array containers, don't touch
>> directly.
>> + * Use dma_fence_unwrap_first/next instead.
>> + */
>> +static inline struct dma_fence *
>> +dma_fence_unwrap_array(struct dma_fence_unwrap * cursor)
>> +{
>> + cursor->array = dma_fence_chain_contained(cursor->chain);
>> + cursor->index = 0;
>> + return dma_fence_array_first(cursor->array);
>> +}
>> +
>> +/**
>> + * dma_fence_unwrap_first - return the first fence from fence
>> containers
>> + * @head: the entrypoint into the containers
>> + * @cursor: current position inside the containers
>> + *
>> + * Unwraps potential dma_fence_chain/dma_fence_array containers and
>> return the
>> + * first fence.
>> + */
>> +static inline struct dma_fence *
>> +dma_fence_unwrap_first(struct dma_fence *head, struct
>> dma_fence_unwrap *cursor)
>> +{
>> + cursor->chain = dma_fence_get(head);
>> + return dma_fence_unwrap_array(cursor);
>> +}
>> +
>> +/**
>> + * dma_fence_unwrap_next - return the next fence from a fence
>> containers
>> + * @cursor: current position inside the containers
>> + *
>> + * Continue unwrapping the dma_fence_chain/dma_fence_array
>> containers and return
>> + * the next fence from them.
>> + */
>> +static inline struct dma_fence *
>> +dma_fence_unwrap_next(struct dma_fence_unwrap *cursor)
>> +{
>> + struct dma_fence *tmp;
>> +
>> + ++cursor->index;
>> + tmp = dma_fence_array_next(cursor->array, cursor->index);
>> + if (tmp)
>> + return tmp;
>> +
>> + cursor->chain = dma_fence_chain_walk(cursor->chain);
>> + return dma_fence_unwrap_array(cursor);
>> +}
>> +
>> +/**
>> + * dma_fence_unwrap_for_each - iterate over all fences in containers
>> + * @fence: current fence
>> + * @cursor: current position inside the containers
>> + * @head: starting point for the iterator
>> + *
>> + * Unwrap dma_fence_chain and dma_fence_array containers and deep
>> dive into all
>> + * potential fences in them. If @head is just a normal fence only
>> that one is
>> + * returned.
>> + */
>> +#define dma_fence_unwrap_for_each(fence, cursor, head) \
>> + for (fence = dma_fence_unwrap_first(head, cursor); fence; \
>> + fence = dma_fence_unwrap_next(cursor))
>> +
>> +#endif
>
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