1 /*- 2 * Copyright (c) 2017 Hans Petter Selasky 3 * All rights reserved. 4 * 5 * Redistribution and use in source and binary forms, with or without 6 * modification, are permitted provided that the following conditions 7 * are met: 8 * 1. Redistributions of source code must retain the above copyright 9 * notice unmodified, this list of conditions, and the following 10 * disclaimer. 11 * 2. Redistributions in binary form must reproduce the above copyright 12 * notice, this list of conditions and the following disclaimer in the 13 * documentation and/or other materials provided with the distribution. 14 * 15 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR 16 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES 17 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. 18 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, 19 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT 20 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, 21 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY 22 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT 23 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF 24 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. 25 */ 26 27 #include <sys/cdefs.h> 28 #include <linux/compat.h> 29 #include <linux/kthread.h> 30 #include <linux/sched.h> 31 #include <linux/wait.h> 32 33 #include <sys/bus.h> 34 #include <sys/interrupt.h> 35 #include <sys/priority.h> 36 37 enum { 38 KTHREAD_SHOULD_STOP_MASK = (1 << 0), 39 KTHREAD_SHOULD_PARK_MASK = (1 << 1), 40 KTHREAD_IS_PARKED_MASK = (1 << 2), 41 }; 42 43 bool 44 linux_kthread_should_stop_task(struct task_struct *task) 45 { 46 47 return (atomic_read(&task->kthread_flags) & KTHREAD_SHOULD_STOP_MASK); 48 } 49 50 bool 51 linux_kthread_should_stop(void) 52 { 53 54 return (atomic_read(¤t->kthread_flags) & KTHREAD_SHOULD_STOP_MASK); 55 } 56 57 int 58 linux_kthread_stop(struct task_struct *task) 59 { 60 int retval; 61 62 /* 63 * Assume task is still alive else caller should not call 64 * kthread_stop(): 65 */ 66 atomic_or(KTHREAD_SHOULD_STOP_MASK, &task->kthread_flags); 67 kthread_unpark(task); 68 wake_up_process(task); 69 wait_for_completion(&task->exited); 70 71 /* 72 * Get return code and free task structure: 73 */ 74 retval = task->task_ret; 75 put_task_struct(task); 76 77 return (retval); 78 } 79 80 int 81 linux_kthread_park(struct task_struct *task) 82 { 83 84 atomic_or(KTHREAD_SHOULD_PARK_MASK, &task->kthread_flags); 85 wake_up_process(task); 86 wait_for_completion(&task->parked); 87 return (0); 88 } 89 90 void 91 linux_kthread_parkme(void) 92 { 93 struct task_struct *task; 94 95 task = current; 96 set_task_state(task, TASK_PARKED | TASK_UNINTERRUPTIBLE); 97 while (linux_kthread_should_park()) { 98 while ((atomic_fetch_or(KTHREAD_IS_PARKED_MASK, 99 &task->kthread_flags) & KTHREAD_IS_PARKED_MASK) == 0) 100 complete(&task->parked); 101 schedule(); 102 set_task_state(task, TASK_PARKED | TASK_UNINTERRUPTIBLE); 103 } 104 atomic_andnot(KTHREAD_IS_PARKED_MASK, &task->kthread_flags); 105 set_task_state(task, TASK_RUNNING); 106 } 107 108 bool 109 linux_kthread_should_park(void) 110 { 111 struct task_struct *task; 112 113 task = current; 114 return (atomic_read(&task->kthread_flags) & KTHREAD_SHOULD_PARK_MASK); 115 } 116 117 void 118 linux_kthread_unpark(struct task_struct *task) 119 { 120 121 atomic_andnot(KTHREAD_SHOULD_PARK_MASK, &task->kthread_flags); 122 if ((atomic_fetch_andnot(KTHREAD_IS_PARKED_MASK, &task->kthread_flags) & 123 KTHREAD_IS_PARKED_MASK) != 0) 124 wake_up_state(task, TASK_PARKED); 125 } 126 127 struct task_struct * 128 linux_kthread_setup_and_run(struct thread *td, linux_task_fn_t *task_fn, void *arg) 129 { 130 struct task_struct *task; 131 132 linux_set_current(td); 133 134 task = td->td_lkpi_task; 135 task->task_fn = task_fn; 136 task->task_data = arg; 137 138 thread_lock(td); 139 /* make sure the scheduler priority is raised */ 140 sched_prio(td, PI_SWI(SWI_NET)); 141 /* put thread into run-queue */ 142 sched_add(td, SRQ_BORING); 143 144 return (task); 145 } 146 147 void 148 linux_kthread_fn(void *arg __unused) 149 { 150 struct task_struct *task = current; 151 152 if (linux_kthread_should_stop_task(task) == 0) 153 task->task_ret = task->task_fn(task->task_data); 154 155 if (linux_kthread_should_stop_task(task) != 0) { 156 struct thread *td = curthread; 157 158 /* let kthread_stop() free data */ 159 td->td_lkpi_task = NULL; 160 161 /* wakeup kthread_stop() */ 162 complete(&task->exited); 163 } 164 kthread_exit(); 165 } 166 167 void 168 lkpi_kthread_work_fn(void *context, int pending __unused) 169 { 170 struct kthread_work *work = context; 171 172 work->func(work); 173 } 174 175 void 176 lkpi_kthread_worker_init_fn(void *context, int pending __unused) 177 { 178 struct kthread_worker *worker = context; 179 180 worker->task = current; 181 } 182