iokit/Kernel/IOCommandPool.cpp

   1 /*
   2  * Copyright (c) 2000 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
   5  *
   6  * This file contains Original Code and/or Modifications of Original Code
   7  * as defined in and that are subject to the Apple Public Source License
   8  * Version 2.0 (the 'License'). You may not use this file except in
   9  * compliance with the License. The rights granted to you under the License
  10  * may not be used to create, or enable the creation or redistribution of,
  11  * unlawful or unlicensed copies of an Apple operating system, or to
  12  * circumvent, violate, or enable the circumvention or violation of, any
  13  * terms of an Apple operating system software license agreement.
  14  *
  15  * Please obtain a copy of the License at
  16  * http://www.opensource.apple.com/apsl/ and read it before using this file.
  17  *
  18  * The Original Code and all software distributed under the License are
  19  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  20  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  21  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  22  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  23  * Please see the License for the specific language governing rights and
  24  * limitations under the License.
  25  *
  26  * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
  27  */
  28
  29 /*
  30  *
  31  *      Copyright (c) 2000 Apple Computer, Inc.  All rights reserved.
  32  *
  33  *      HISTORY
  34  *
  35  *      2001-01-17      gvdl    Re-implement on IOCommandGate::commandSleep
  36  *      10/9/2000       CJS     Created IOCommandPool class and implementation
  37  *
  38  */
  39
  40 #include <IOKit/IOCommandPool.h>
  41
  42 #define super OSObject
  43 OSDefineMetaClassAndStructors(IOCommandPool, OSObject);
  44 OSMetaClassDefineReservedUnused(IOCommandPool, 0);
  45 OSMetaClassDefineReservedUnused(IOCommandPool, 1);
  46 OSMetaClassDefineReservedUnused(IOCommandPool, 2);
  47 OSMetaClassDefineReservedUnused(IOCommandPool, 3);
  48 OSMetaClassDefineReservedUnused(IOCommandPool, 4);
  49 OSMetaClassDefineReservedUnused(IOCommandPool, 5);
  50 OSMetaClassDefineReservedUnused(IOCommandPool, 6);
  51 OSMetaClassDefineReservedUnused(IOCommandPool, 7);
  52
  53 //--------------------------------------------------------------------------
  54 //      withWorkLoop -  primary initializer and factory method
  55 //--------------------------------------------------------------------------
  56
  57 IOCommandPool *IOCommandPool::
  58 withWorkLoop(IOWorkLoop *inWorkLoop)
  59 {
  60     IOCommandPool * me = new IOCommandPool;
  61
  62     if (me && !me->initWithWorkLoop(inWorkLoop)) {
  63         me->release();
  64         return 0;
  65     }
  66
  67     return me;
  68 }
  69
  70
  71 bool IOCommandPool::
  72 initWithWorkLoop(IOWorkLoop *inWorkLoop)
  73 {
  74     assert(inWorkLoop);
  75
  76     if (!super::init())
  77         return false;
  78
  79     queue_init(&fQueueHead);
  80
  81     fSerializer = IOCommandGate::commandGate(this);
  82     assert(fSerializer);
  83     if (!fSerializer)
  84         return false;
  85
  86     if (kIOReturnSuccess != inWorkLoop->addEventSource(fSerializer))
  87         return false;
  88
  89     return true;
  90 }
  91
  92 //--------------------------------------------------------------------------
  93 //      commandPool & init -    obsolete initializer and factory method
  94 //--------------------------------------------------------------------------
  95
  96 IOCommandPool *IOCommandPool::
  97 commandPool(IOService * inOwner, IOWorkLoop *inWorkLoop, UInt32 inSize)
  98 {
  99     IOCommandPool * me = new IOCommandPool;
 100
 101     if (me && !me->init(inOwner, inWorkLoop, inSize)) {
 102         me->release();
 103         return 0;
 104     }
 105
 106     return me;
 107 }
 108
 109 bool IOCommandPool::
 110 init(IOService */* inOwner */, IOWorkLoop *inWorkLoop, UInt32 /* inSize */)
 111 {
 112     return initWithWorkLoop(inWorkLoop);
 113 }
 114
 115
 116 //--------------------------------------------------------------------------
 117 //      free -  free all allocated resources
 118 //--------------------------------------------------------------------------
 119
 120 void
 121 IOCommandPool::free(void)
 122 {
 123     if (fSerializer) {
 124         // remove our event source from owner's workloop
 125         IOWorkLoop *wl = fSerializer->getWorkLoop();
 126         if (wl)
 127             wl->removeEventSource(fSerializer);
 128
 129         fSerializer->release();
 130         fSerializer = 0;
 131     }
 132
 133     // Tell our superclass to cleanup too
 134     super::free();
 135 }
 136
 137
 138 //--------------------------------------------------------------------------
 139 //      getCommand -    Gets a command from the pool. Pass true in
 140 //                      blockForCommand if you want your thread to sleep
 141 //                      waiting for resources
 142 //--------------------------------------------------------------------------
 143
 144 IOCommand *
 145 IOCommandPool::getCommand(bool blockForCommand)
 146 {
 147     IOReturn     result  = kIOReturnSuccess;
 148     IOCommand *command = 0;
 149
 150     result = fSerializer->runAction((IOCommandGate::Action)
 151         &IOCommandPool::gatedGetCommand,
 152             (void *) &command, (void *) blockForCommand);
 153     if (kIOReturnSuccess == result)
 154         return command;
 155     else
 156         return 0;
 157 }
 158
 159
 160 //--------------------------------------------------------------------------
 161 //      gatedGetCommand -       Static callthrough function
 162 //                              (on safe side of command gate)
 163 //--------------------------------------------------------------------------
 164
 165 IOReturn IOCommandPool::
 166 gatedGetCommand(IOCommand **command, bool blockForCommand)
 167 {
 168     while (queue_empty(&fQueueHead)) {
 169         if (!blockForCommand)
 170             return kIOReturnNoResources;
 171
 172         fSleepers++;
 173         fSerializer->commandSleep(&fSleepers, THREAD_UNINT);
 174     }
 175
 176     queue_remove_first(&fQueueHead,
 177                        *command, IOCommand *, fCommandChain);
 178     return kIOReturnSuccess;
 179 }
 180
 181
 182 //--------------------------------------------------------------------------
 183 //      returnCommand -         Returns command to the pool.
 184 //--------------------------------------------------------------------------
 185
 186 void IOCommandPool::
 187 returnCommand(IOCommand *command)
 188 {
 189     (void) fSerializer->runAction((IOCommandGate::Action)
 190         &IOCommandPool::gatedReturnCommand, (void *) command);
 191 }
 192
 193
 194 //--------------------------------------------------------------------------
 195 //      gatedReturnCommand -    Callthrough function
 196 //                              (on safe side of command gate)
 197 //--------------------------------------------------------------------------
 198
 199 IOReturn IOCommandPool::
 200 gatedReturnCommand(IOCommand *command)
 201 {
 202     queue_enter(&fQueueHead, command, IOCommand *, fCommandChain);
 203     if (fSleepers) {
 204         fSerializer->commandWakeup(&fSleepers, /* oneThread */ true);
 205         fSleepers--;
 206     }
 207     return kIOReturnSuccess;
 208 }