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 __FBSDID("$FreeBSD$"); 29 30 #include <linux/compat.h> 31 #include <linux/kthread.h> 32 #include <linux/sched.h> 33 #include <linux/wait.h> 34 35 #include <sys/bus.h> 36 #include <sys/interrupt.h> 37 #include <sys/priority.h> 38 39 enum { 40 KTHREAD_SHOULD_STOP_MASK = (1 << 0), 41 KTHREAD_SHOULD_PARK_MASK = (1 << 1), 42 KTHREAD_IS_PARKED_MASK = (1 << 2), 43 }; 44 45 bool 46 linux_kthread_should_stop_task(struct task_struct *task) 47 { 48 49 return (atomic_read(&task->kthread_flags) & KTHREAD_SHOULD_STOP_MASK); 50 } 51 52 bool 53 linux_kthread_should_stop(void) 54 { 55 56 return (atomic_read(¤t->kthread_flags) & KTHREAD_SHOULD_STOP_MASK); 57 } 58 59 int 60 linux_kthread_stop(struct task_struct *task) 61 { 62 int retval; 63 64 /* 65 * Assume task is still alive else caller should not call 66 * kthread_stop(): 67 */ 68 atomic_or(KTHREAD_SHOULD_STOP_MASK, &task->kthread_flags); 69 kthread_unpark(task); 70 wake_up_process(task); 71 wait_for_completion(&task->exited); 72 73 /* 74 * Get return code and free task structure: 75 */ 76 retval = task->task_ret; 77 put_task_struct(task); 78 79 return (retval); 80 } 81 82 int 83 linux_kthread_park(struct task_struct *task) 84 { 85 86 atomic_or(KTHREAD_SHOULD_PARK_MASK, &task->kthread_flags); 87 wake_up_process(task); 88 wait_for_completion(&task->parked); 89 return (0); 90 } 91 92 void 93 linux_kthread_parkme(void) 94 { 95 struct task_struct *task; 96 97 task = current; 98 set_task_state(task, TASK_PARKED | TASK_UNINTERRUPTIBLE); 99 while (linux_kthread_should_park()) { 100 while ((atomic_fetch_or(KTHREAD_IS_PARKED_MASK, 101 &task->kthread_flags) & KTHREAD_IS_PARKED_MASK) == 0) 102 complete(&task->parked); 103 schedule(); 104 set_task_state(task, TASK_PARKED | TASK_UNINTERRUPTIBLE); 105 } 106 atomic_andnot(KTHREAD_IS_PARKED_MASK, &task->kthread_flags); 107 set_task_state(task, TASK_RUNNING); 108 } 109 110 bool 111 linux_kthread_should_park(void) 112 { 113 struct task_struct *task; 114 115 task = current; 116 return (atomic_read(&task->kthread_flags) & KTHREAD_SHOULD_PARK_MASK); 117 } 118 119 void 120 linux_kthread_unpark(struct task_struct *task) 121 { 122 123 atomic_andnot(KTHREAD_SHOULD_PARK_MASK, &task->kthread_flags); 124 if ((atomic_fetch_andnot(KTHREAD_IS_PARKED_MASK, &task->kthread_flags) & 125 KTHREAD_IS_PARKED_MASK) != 0) 126 wake_up_state(task, TASK_PARKED); 127 } 128 129 struct task_struct * 130 linux_kthread_setup_and_run(struct thread *td, linux_task_fn_t *task_fn, void *arg) 131 { 132 struct task_struct *task; 133 134 linux_set_current(td); 135 136 task = td->td_lkpi_task; 137 task->task_fn = task_fn; 138 task->task_data = arg; 139 140 thread_lock(td); 141 /* make sure the scheduler priority is raised */ 142 sched_prio(td, PI_SWI(SWI_NET)); 143 /* put thread into run-queue */ 144 sched_add(td, SRQ_BORING); 145 146 return (task); 147 } 148 149 void 150 linux_kthread_fn(void *arg __unused) 151 { 152 struct task_struct *task = current; 153 154 if (linux_kthread_should_stop_task(task) == 0) 155 task->task_ret = task->task_fn(task->task_data); 156 157 if (linux_kthread_should_stop_task(task) != 0) { 158 struct thread *td = curthread; 159 160 /* let kthread_stop() free data */ 161 td->td_lkpi_task = NULL; 162 163 /* wakeup kthread_stop() */ 164 complete(&task->exited); 165 } 166 kthread_exit(); 167 } 168 169 void 170 lkpi_kthread_work_fn(void *context, int pending __unused) 171 { 172 struct kthread_work *work = context; 173 174 work->func(work); 175 } 176 177 void 178 lkpi_kthread_worker_init_fn(void *context, int pending __unused) 179 { 180 struct kthread_worker *worker = context; 181 182 worker->task = current; 183 } 184