iokit/Kernel/IOCommandPool.cpp

   1 /*
   2  * Copyright (c) 2000 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_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. Please obtain a copy of the License at
  10  * http://www.opensource.apple.com/apsl/ and read it before using this
  11  * file.
  12  *
  13  * The Original Code and all software distributed under the License are
  14  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  15  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  16  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  17  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  18  * Please see the License for the specific language governing rights and
  19  * limitations under the License.
  20  *
  21  * @APPLE_LICENSE_HEADER_END@
  22  */
  23
  24 /*
  25  *
  26  *      Copyright (c) 2000 Apple Computer, Inc.  All rights reserved.
  27  *
  28  *      HISTORY
  29  *
  30  *      2001-01-17      gvdl    Re-implement on IOCommandGate::commandSleep
  31  *      10/9/2000       CJS     Created IOCommandPool class and implementation
  32  *
  33  */
  34
  35 #include <IOKit/IOCommandPool.h>
  36
  37 #define super OSObject
  38 OSDefineMetaClassAndStructors(IOCommandPool, OSObject);
  39 OSMetaClassDefineReservedUnused(IOCommandPool, 0);
  40 OSMetaClassDefineReservedUnused(IOCommandPool, 1);
  41 OSMetaClassDefineReservedUnused(IOCommandPool, 2);
  42 OSMetaClassDefineReservedUnused(IOCommandPool, 3);
  43 OSMetaClassDefineReservedUnused(IOCommandPool, 4);
  44 OSMetaClassDefineReservedUnused(IOCommandPool, 5);
  45 OSMetaClassDefineReservedUnused(IOCommandPool, 6);
  46 OSMetaClassDefineReservedUnused(IOCommandPool, 7);
  47
  48 //--------------------------------------------------------------------------
  49 //      withWorkLoop -  primary initializer and factory method
  50 //--------------------------------------------------------------------------
  51
  52 IOCommandPool *IOCommandPool::
  53 withWorkLoop(IOWorkLoop *inWorkLoop)
  54 {
  55     IOCommandPool * me = new IOCommandPool;
  56
  57     if (me && !me->initWithWorkLoop(inWorkLoop)) {
  58         me->release();
  59         return 0;
  60     }
  61
  62     return me;
  63 }
  64
  65
  66 bool IOCommandPool::
  67 initWithWorkLoop(IOWorkLoop *inWorkLoop)
  68 {
  69     assert(inWorkLoop);
  70
  71     if (!super::init())
  72         return false;
  73
  74     queue_init(&fQueueHead);
  75
  76     fSerializer = IOCommandGate::commandGate(this);
  77     assert(fSerializer);
  78     if (!fSerializer)
  79         return false;
  80
  81     if (kIOReturnSuccess != inWorkLoop->addEventSource(fSerializer))
  82         return false;
  83
  84     return true;
  85 }
  86
  87 //--------------------------------------------------------------------------
  88 //      commandPool & init -    obsolete initializer and factory method
  89 //--------------------------------------------------------------------------
  90
  91 IOCommandPool *IOCommandPool::
  92 commandPool(IOService * inOwner, IOWorkLoop *inWorkLoop, UInt32 inSize)
  93 {
  94     IOCommandPool * me = new IOCommandPool;
  95
  96     if (me && !me->init(inOwner, inWorkLoop, inSize)) {
  97         me->release();
  98         return 0;
  99     }
 100
 101     return me;
 102 }
 103
 104 bool IOCommandPool::
 105 init(IOService */* inOwner */, IOWorkLoop *inWorkLoop, UInt32 /* inSize */)
 106 {
 107     return initWithWorkLoop(inWorkLoop);
 108 }
 109
 110
 111 //--------------------------------------------------------------------------
 112 //      free -  free all allocated resources
 113 //--------------------------------------------------------------------------
 114
 115 void
 116 IOCommandPool::free(void)
 117 {
 118     if (fSerializer) {
 119         // remove our event source from owner's workloop
 120         IOWorkLoop *wl = fSerializer->getWorkLoop();
 121         if (wl)
 122             wl->removeEventSource(fSerializer);
 123
 124         fSerializer->release();
 125         fSerializer = 0;
 126     }
 127
 128     // Tell our superclass to cleanup too
 129     super::free();
 130 }
 131
 132
 133 //--------------------------------------------------------------------------
 134 //      getCommand -    Gets a command from the pool. Pass true in
 135 //                      blockForCommand if you want your thread to sleep
 136 //                      waiting for resources
 137 //--------------------------------------------------------------------------
 138
 139 IOCommand *
 140 IOCommandPool::getCommand(bool blockForCommand)
 141 {
 142     IOReturn     result  = kIOReturnSuccess;
 143     IOCommand *command = 0;
 144
 145     result = fSerializer->runAction((IOCommandGate::Action)
 146         &IOCommandPool::gatedGetCommand,
 147             (void *) &command, (void *) blockForCommand);
 148     if (kIOReturnSuccess == result)
 149         return command;
 150     else
 151         return 0;
 152 }
 153
 154
 155 //--------------------------------------------------------------------------
 156 //      gatedGetCommand -       Static callthrough function
 157 //                              (on safe side of command gate)
 158 //--------------------------------------------------------------------------
 159
 160 IOReturn IOCommandPool::
 161 gatedGetCommand(IOCommand **command, bool blockForCommand)
 162 {
 163     while (queue_empty(&fQueueHead)) {
 164         if (!blockForCommand)
 165             return kIOReturnNoResources;
 166
 167         fSleepers++;
 168         fSerializer->commandSleep(&fSleepers, THREAD_UNINT);
 169     }
 170
 171     queue_remove_first(&fQueueHead,
 172                        *command, IOCommand *, fCommandChain);
 173     return kIOReturnSuccess;
 174 }
 175
 176
 177 //--------------------------------------------------------------------------
 178 //      returnCommand -         Returns command to the pool.
 179 //--------------------------------------------------------------------------
 180
 181 void IOCommandPool::
 182 returnCommand(IOCommand *command)
 183 {
 184     (void) fSerializer->runAction((IOCommandGate::Action)
 185         &IOCommandPool::gatedReturnCommand, (void *) command);
 186 }
 187
 188
 189 //--------------------------------------------------------------------------
 190 //      gatedReturnCommand -    Callthrough function
 191 //                              (on safe side of command gate)
 192 //--------------------------------------------------------------------------
 193
 194 IOReturn IOCommandPool::
 195 gatedReturnCommand(IOCommand *command)
 196 {
 197     queue_enter(&fQueueHead, command, IOCommand *, fCommandChain);
 198     if (fSleepers) {
 199         fSerializer->commandWakeup(&fSleepers, /* oneThread */ true);
 200         fSleepers--;
 201     }
 202     return kIOReturnSuccess;
 203 }