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      1 /*	$NetBSD: lib_sw_fence.c,v 1.2 2021/12/18 23:45:31 riastradh Exp $	*/
      2 
      3 /*
      4  * Copyright  2017 Intel Corporation
      5  *
      6  * Permission is hereby granted, free of charge, to any person obtaining a
      7  * copy of this software and associated documentation files (the "Software"),
      8  * to deal in the Software without restriction, including without limitation
      9  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
     10  * and/or sell copies of the Software, and to permit persons to whom the
     11  * Software is furnished to do so, subject to the following conditions:
     12  *
     13  * The above copyright notice and this permission notice (including the next
     14  * paragraph) shall be included in all copies or substantial portions of the
     15  * Software.
     16  *
     17  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
     18  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
     19  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
     20  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
     21  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
     22  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
     23  * IN THE SOFTWARE.
     24  *
     25  */
     26 
     27 #include <sys/cdefs.h>
     28 __KERNEL_RCSID(0, "$NetBSD: lib_sw_fence.c,v 1.2 2021/12/18 23:45:31 riastradh Exp $");
     29 
     30 #include "lib_sw_fence.h"
     31 
     32 /* Small library of different fence types useful for writing tests */
     33 
     34 static int __i915_sw_fence_call
     35 nop_fence_notify(struct i915_sw_fence *fence, enum i915_sw_fence_notify state)
     36 {
     37 	return NOTIFY_DONE;
     38 }
     39 
     40 void __onstack_fence_init(struct i915_sw_fence *fence,
     41 			  const char *name,
     42 			  struct lock_class_key *key)
     43 {
     44 	debug_fence_init_onstack(fence);
     45 
     46 	__init_waitqueue_head(&fence->wait, name, key);
     47 	atomic_set(&fence->pending, 1);
     48 	fence->error = 0;
     49 	fence->flags = (unsigned long)nop_fence_notify;
     50 }
     51 
     52 void onstack_fence_fini(struct i915_sw_fence *fence)
     53 {
     54 	if (!fence->flags)
     55 		return;
     56 
     57 	i915_sw_fence_commit(fence);
     58 	i915_sw_fence_fini(fence);
     59 }
     60 
     61 static void timed_fence_wake(struct timer_list *t)
     62 {
     63 	struct timed_fence *tf = from_timer(tf, t, timer);
     64 
     65 	i915_sw_fence_commit(&tf->fence);
     66 }
     67 
     68 void timed_fence_init(struct timed_fence *tf, unsigned long expires)
     69 {
     70 	onstack_fence_init(&tf->fence);
     71 
     72 	timer_setup_on_stack(&tf->timer, timed_fence_wake, 0);
     73 
     74 	if (time_after(expires, jiffies))
     75 		mod_timer(&tf->timer, expires);
     76 	else
     77 		i915_sw_fence_commit(&tf->fence);
     78 }
     79 
     80 void timed_fence_fini(struct timed_fence *tf)
     81 {
     82 	if (del_timer_sync(&tf->timer))
     83 		i915_sw_fence_commit(&tf->fence);
     84 
     85 	destroy_timer_on_stack(&tf->timer);
     86 	i915_sw_fence_fini(&tf->fence);
     87 }
     88 
     89 struct heap_fence {
     90 	struct i915_sw_fence fence;
     91 	union {
     92 		struct kref ref;
     93 		struct rcu_head rcu;
     94 	};
     95 };
     96 
     97 static int __i915_sw_fence_call
     98 heap_fence_notify(struct i915_sw_fence *fence, enum i915_sw_fence_notify state)
     99 {
    100 	struct heap_fence *h = container_of(fence, typeof(*h), fence);
    101 
    102 	switch (state) {
    103 	case FENCE_COMPLETE:
    104 		break;
    105 
    106 	case FENCE_FREE:
    107 		heap_fence_put(&h->fence);
    108 	}
    109 
    110 	return NOTIFY_DONE;
    111 }
    112 
    113 struct i915_sw_fence *heap_fence_create(gfp_t gfp)
    114 {
    115 	struct heap_fence *h;
    116 
    117 	h = kmalloc(sizeof(*h), gfp);
    118 	if (!h)
    119 		return NULL;
    120 
    121 	i915_sw_fence_init(&h->fence, heap_fence_notify);
    122 	refcount_set(&h->ref.refcount, 2);
    123 
    124 	return &h->fence;
    125 }
    126 
    127 static void heap_fence_release(struct kref *ref)
    128 {
    129 	struct heap_fence *h = container_of(ref, typeof(*h), ref);
    130 
    131 	i915_sw_fence_fini(&h->fence);
    132 
    133 	kfree_rcu(h, rcu);
    134 }
    135 
    136 void heap_fence_put(struct i915_sw_fence *fence)
    137 {
    138 	struct heap_fence *h = container_of(fence, typeof(*h), fence);
    139 
    140 	kref_put(&h->ref, heap_fence_release);
    141 }
    142