1 /* 2 * Copyright (c) 2014 The DragonFly Project. All rights reserved. 3 * 4 * This code is derived from software contributed to The DragonFly Project 5 * by Matthew Dillon <dillon@backplane.com> 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 * 11 * 1. Redistributions of source code must retain the above copyright 12 * notice, this list of conditions and the following disclaimer. 13 * 2. Redistributions in binary form must reproduce the above copyright 14 * notice, this list of conditions and the following disclaimer in 15 * the documentation and/or other materials provided with the 16 * distribution. 17 * 3. Neither the name of The DragonFly Project nor the names of its 18 * contributors may be used to endorse or promote products derived 19 * from this software without specific, prior written permission. 20 * 21 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS 22 * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT 23 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS 24 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE 25 * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, 26 * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING, 27 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; 28 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED 29 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, 30 * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT 31 * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 32 * SUCH DAMAGE. 33 */ 34 /* 35 * Copyright (c) 1990, 1993 36 * The Regents of the University of California. All rights reserved. 37 * (c) UNIX System Laboratories, Inc. 38 * 39 * All or some portions of this file are derived from material licensed 40 * to the University of California by American Telephone and Telegraph 41 * Co. or Unix System Laboratories, Inc. and are reproduced herein with 42 * the permission of UNIX System Laboratories, Inc. 43 * 44 * Redistribution and use in source and binary forms, with or without 45 * modification, are permitted provided that the following conditions 46 * are met: 47 * 1. Redistributions of source code must retain the above copyright 48 * notice, this list of conditions and the following disclaimer. 49 * 2. Redistributions in binary form must reproduce the above copyright 50 * notice, this list of conditions and the following disclaimer in the 51 * documentation and/or other materials provided with the distribution. 52 * 3. All advertising materials mentioning features or use of this software 53 * must display the following acknowledgement: 54 * This product includes software developed by the University of 55 * California, Berkeley and its contributors. 56 * 4. Neither the name of the University nor the names of its contributors 57 * may be used to endorse or promote products derived from this software 58 * without specific prior written permission. 59 * 60 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 61 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 62 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 63 * ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 64 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 65 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 66 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 67 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 68 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 69 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 70 * SUCH DAMAGE. 71 */ 72 73 #ifndef _SYS_CALLOUT_H_ 74 #define _SYS_CALLOUT_H_ 75 76 #ifndef _SYS_QUEUE_H_ 77 #include <sys/queue.h> 78 #endif 79 #ifndef _SYS_LOCK_H_ 80 #include <sys/lock.h> 81 #endif 82 #ifndef _CPU_ATOMIC_H_ 83 #include <machine/atomic.h> 84 #endif 85 86 SLIST_HEAD(callout_list, callout); 87 TAILQ_HEAD(callout_tailq, callout); 88 89 /* 90 * Callwheel linkages are only adjusted on the target cpu. All other 91 * actions are handled with atomic ops on any cpu. callout_reset() and 92 * callout_stop() are always synchronous and will interlock against a 93 * running callout. The caller might block, and a deadlock is possible 94 * if the caller does not use callout_init_lk() or is not careful with 95 * locks acquired in the callout function. 96 * 97 * Programers should note that our lockmgr locks have a cancelation feature 98 * which can be used to avoid deadlocks. callout_init_lk() also uses this 99 * feature. 100 * 101 * callout_deactivate() is asynchronous and will not interlock against 102 * callout which is already running. 103 */ 104 struct callout { 105 union { 106 SLIST_ENTRY(callout) sle; 107 TAILQ_ENTRY(callout) tqe; 108 } c_links; 109 int c_time; /* match tick on event */ 110 int c_load; /* load value for reset ipi */ 111 void *c_arg; /* function argument */ 112 void (*c_func) (void *); /* function to call */ 113 int c_flags; /* state of this entry */ 114 int c_unused02; 115 struct lock *c_lk; /* auto-lock */ 116 }; 117 118 #define CALLOUT_ACTIVE 0x80000000 /* quick [de]activation flag */ 119 #define CALLOUT_PENDING 0x40000000 /* callout is on callwheel */ 120 #define CALLOUT_MPSAFE 0x20000000 /* callout does not need the BGL */ 121 #define CALLOUT_DID_INIT 0x10000000 /* safety check */ 122 #define CALLOUT_AUTOLOCK 0x08000000 /* auto locking / cancel feature */ 123 #define CALLOUT_WAITING 0x04000000 /* interlocked waiter */ 124 #define CALLOUT_EXECUTED 0x02000000 /* (generates stop status) */ 125 #define CALLOUT_ARMED 0x01000000 /* callout is assigned to cpu */ 126 #define CALLOUT_IPI_MASK 0x00000FFF /* ipi in-flight count mask */ 127 #define CALLOUT_CPU_MASK 0x00FFF000 /* ipi in-flight count mask */ 128 129 #define CALLOUT_FLAGS_TO_CPU(flags) (((flags) & CALLOUT_CPU_MASK) >> 12) 130 #define CALLOUT_CPU_TO_FLAGS(cpuid) ((cpuid) << 12) 131 132 /* 133 * WARNING! The caller is responsible for stabilizing the callout state, 134 * our suggestion is to either manage the callout on the same cpu 135 * or to use the callout_init_lk() feature and hold the lock while 136 * making callout_*() calls. The lock will be held automatically 137 * by the callout wheel for any call-back and the callout wheel 138 * will handle any callout_stop() deadlocks properly. 139 * 140 * active - Indicates that the callout is armed. The callout can be in 141 * any state other than a stopped state. That is, the callout 142 * reset could still be inflight to the target cpu and not yet 143 * pending on the target cpu's callwheel, could be pending on 144 * the callwheel, may have already executed (but not have been 145 * stopped), or might be executing concurrently. 146 * 147 * deactivate - Disarm the callout, preventing it from being executed if it 148 * is queued or the queueing operation is in-flight. Has no 149 * effect if the callout has already been dispatched. Does not 150 * dequeue the callout. Does not affect the status returned 151 * by callout_stop(). 152 * 153 * Not serialized, caller must be careful when racing a new 154 * callout_reset() that might be issued by the callback, which 155 * will re-arm the callout. 156 * 157 * pending - Only useful for same-cpu callouts, indicates that the callout 158 * is pending on the callwheel or that a callout_reset() ipi 159 * is in-flight. 160 */ 161 #define callout_active(c) ((c)->c_flags & CALLOUT_ACTIVE) 162 163 #define callout_deactivate(c) atomic_clear_int(&(c)->c_flags, CALLOUT_ACTIVE) 164 165 #define callout_pending(c) ((c)->c_flags & (CALLOUT_PENDING | \ 166 CALLOUT_IPI_MASK)) 167 168 #ifdef _KERNEL 169 extern int ncallout; 170 171 struct globaldata; 172 173 void hardclock_softtick(struct globaldata *); 174 void callout_init (struct callout *); 175 void callout_init_mp (struct callout *); 176 void callout_init_lk (struct callout *, struct lock *); 177 void callout_reset (struct callout *, int, void (*)(void *), void *); 178 int callout_stop (struct callout *); 179 void callout_stop_async (struct callout *); 180 int callout_stop_sync (struct callout *); 181 void callout_terminate (struct callout *); 182 void callout_reset_bycpu (struct callout *, int, void (*)(void *), void *, 183 int); 184 185 #define callout_drain(x) callout_stop_sync(x) 186 187 #endif 188 189 #endif /* _SYS_CALLOUT_H_ */ 190