1 /* $NetBSD: task_barrier.h,v 1.1 2021/12/19 10:58:29 riastradh Exp $ */ 2 3 /*- 4 * Copyright (c) 2020 The NetBSD Foundation, Inc. 5 * All rights reserved. 6 * 7 * Redistribution and use in source and binary forms, with or without 8 * modification, are permitted provided that the following conditions 9 * are met: 10 * 1. Redistributions of source code must retain the above copyright 11 * notice, this list of conditions and the following disclaimer. 12 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 16 * THIS SOFTWARE IS PROVIDED BY THE NETBSD FOUNDATION, INC. AND CONTRIBUTORS 17 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED 18 * TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR 19 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE FOUNDATION OR CONTRIBUTORS 20 * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 21 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 22 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 23 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 24 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 25 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 26 * POSSIBILITY OF SUCH DAMAGE. 27 */ 28 29 #ifndef _DRM_TASK_BARRIER_H_ 30 #define _DRM_TASK_BARRIER_H_ 31 32 #include <sys/condvar.h> 33 #include <sys/mutex.h> 34 35 struct task_barrier { 36 kmutex_t tb_lock; 37 kcondvar_t tb_cv; 38 unsigned tb_cur; 39 unsigned tb_gen; 40 unsigned tb_max; 41 }; 42 43 static inline void 44 task_barrier_init(struct task_barrier *tb) 45 { 46 47 mutex_init(&tb->tb_lock, MUTEX_DEFAULT, IPL_VM); 48 cv_init(&tb->tb_cv, "taskbar"); 49 tb->tb_cur = 0; 50 tb->tb_gen = 0; 51 tb->tb_max = 0; 52 } 53 54 static inline void 55 task_barrier_destroy(struct task_barrier *tb) 56 { 57 58 KASSERT(tb->tb_cur == 0); 59 cv_destroy(&tb->tb_cv); 60 mutex_destroy(&tb->tb_lock); 61 } 62 63 static inline void 64 task_barrier_add_task(struct task_barrier *tb) 65 { 66 67 tb->tb_max++; 68 } 69 70 static inline void 71 task_barrier_rem_task(struct task_barrier *tb) 72 { 73 74 tb->tb_max--; 75 } 76 77 static inline void 78 task_barrier_enter(struct task_barrier *tb) 79 { 80 81 mutex_enter(&tb->tb_lock); 82 KASSERT(tb->tb_cur < tb->tb_max); 83 if (++tb->tb_cur < tb->tb_max) { 84 unsigned gen = tb->tb_gen; 85 do { 86 cv_wait(&tb->tb_cv, &tb->tb_lock); 87 } while (gen == tb->tb_gen); 88 } else { 89 tb->tb_gen++; 90 cv_broadcast(&tb->tb_cv); 91 } 92 mutex_exit(&tb->tb_lock); 93 } 94 95 static inline void 96 task_barrier_exit(struct task_barrier *tb) 97 { 98 99 mutex_enter(&tb->tb_lock); 100 KASSERT(tb->tb_cur > 0); 101 if (--tb->tb_cur > 0) { 102 unsigned gen = tb->tb_gen; 103 do { 104 cv_wait(&tb->tb_cv, &tb->tb_lock); 105 } while (gen == tb->tb_gen); 106 } else { 107 tb->tb_gen++; 108 cv_broadcast(&tb->tb_cv); 109 } 110 } 111 112 static inline void 113 task_barrier_full(struct task_barrier *tb) 114 { 115 116 task_barrier_enter(tb); 117 task_barrier_exit(tb); 118 } 119 120 #endif /* _DRM_TASK_BARRIER_H_ */ 121