fence-array.c
4.26 KB
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/*
* fence-array: aggregate fences to be waited together
*
* Copyright (C) 2016 Collabora Ltd
* Copyright (C) 2016 Advanced Micro Devices, Inc.
* Authors:
* Gustavo Padovan <gustavo@padovan.org>
* Christian König <christian.koenig@amd.com>
*
* This program is free software; you can redistribute it and/or modify it
* under the terms of the GNU General Public License version 2 as published by
* the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful, but WITHOUT
* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
* more details.
*/
#include <linux/export.h>
#include <linux/slab.h>
#include <linux/fence-array.h>
static void fence_array_cb_func(struct fence *f, struct fence_cb *cb);
static const char *fence_array_get_driver_name(struct fence *fence)
{
return "fence_array";
}
static const char *fence_array_get_timeline_name(struct fence *fence)
{
return "unbound";
}
static void fence_array_cb_func(struct fence *f, struct fence_cb *cb)
{
struct fence_array_cb *array_cb =
container_of(cb, struct fence_array_cb, cb);
struct fence_array *array = array_cb->array;
if (atomic_dec_and_test(&array->num_pending))
fence_signal(&array->base);
fence_put(&array->base);
}
static bool fence_array_enable_signaling(struct fence *fence)
{
struct fence_array *array = to_fence_array(fence);
struct fence_array_cb *cb = (void *)(&array[1]);
unsigned i;
for (i = 0; i < array->num_fences; ++i) {
cb[i].array = array;
/*
* As we may report that the fence is signaled before all
* callbacks are complete, we need to take an additional
* reference count on the array so that we do not free it too
* early. The core fence handling will only hold the reference
* until we signal the array as complete (but that is now
* insufficient).
*/
fence_get(&array->base);
if (fence_add_callback(array->fences[i], &cb[i].cb,
fence_array_cb_func)) {
fence_put(&array->base);
if (atomic_dec_and_test(&array->num_pending))
return false;
}
}
return true;
}
static bool fence_array_signaled(struct fence *fence)
{
struct fence_array *array = to_fence_array(fence);
return atomic_read(&array->num_pending) <= 0;
}
static void fence_array_release(struct fence *fence)
{
struct fence_array *array = to_fence_array(fence);
unsigned i;
for (i = 0; i < array->num_fences; ++i)
fence_put(array->fences[i]);
kfree(array->fences);
fence_free(fence);
}
const struct fence_ops fence_array_ops = {
.get_driver_name = fence_array_get_driver_name,
.get_timeline_name = fence_array_get_timeline_name,
.enable_signaling = fence_array_enable_signaling,
.signaled = fence_array_signaled,
.wait = fence_default_wait,
.release = fence_array_release,
};
EXPORT_SYMBOL(fence_array_ops);
/**
* fence_array_create - Create a custom fence array
* @num_fences: [in] number of fences to add in the array
* @fences: [in] array containing the fences
* @context: [in] fence context to use
* @seqno: [in] sequence number to use
* @signal_on_any: [in] signal on any fence in the array
*
* Allocate a fence_array object and initialize the base fence with fence_init().
* In case of error it returns NULL.
*
* The caller should allocate the fences array with num_fences size
* and fill it with the fences it wants to add to the object. Ownership of this
* array is taken and fence_put() is used on each fence on release.
*
* If @signal_on_any is true the fence array signals if any fence in the array
* signals, otherwise it signals when all fences in the array signal.
*/
struct fence_array *fence_array_create(int num_fences, struct fence **fences,
u64 context, unsigned seqno,
bool signal_on_any)
{
struct fence_array *array;
size_t size = sizeof(*array);
/* Allocate the callback structures behind the array. */
size += num_fences * sizeof(struct fence_array_cb);
array = kzalloc(size, GFP_KERNEL);
if (!array)
return NULL;
spin_lock_init(&array->lock);
fence_init(&array->base, &fence_array_ops, &array->lock,
context, seqno);
array->num_fences = num_fences;
atomic_set(&array->num_pending, signal_on_any ? 1 : num_fences);
array->fences = fences;
return array;
}
EXPORT_SYMBOL(fence_array_create);