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