iokit/Kernel/IOCommandPool.cpp

   1 /*
   2  * Copyright (c) 2000 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   6  * Copyright (c) 1999-2003 Apple Computer, Inc.  All Rights Reserved.
   7  *
   8  * This file contains Original Code and/or Modifications of Original Code
   9  * as defined in and that are subject to the Apple Public Source License
  10  * Version 2.0 (the 'License'). You may not use this file except in
  11  * compliance with the License. Please obtain a copy of the License at
  12  * http://www.opensource.apple.com/apsl/ and read it before using this
  13  * file.
  14  *
  15  * The Original Code and all software distributed under the License are
  16  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  17  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  18  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  19  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  20  * Please see the License for the specific language governing rights and
  21  * limitations under the License.
  22  *
  23  * @APPLE_LICENSE_HEADER_END@
  24  */
  25
  26 /*
  27  *
  28  *      Copyright (c) 2000 Apple Computer, Inc.  All rights reserved.
  29  *
  30  *      HISTORY
  31  *
  32  *      2001-01-17      gvdl    Re-implement on IOCommandGate::commandSleep
  33  *      10/9/2000       CJS     Created IOCommandPool class and implementation
  34  *
  35  */
  36
  37 #include <IOKit/IOCommandPool.h>
  38
  39 #define super OSObject
  40 OSDefineMetaClassAndStructors(IOCommandPool, OSObject);
  41 OSMetaClassDefineReservedUnused(IOCommandPool, 0);
  42 OSMetaClassDefineReservedUnused(IOCommandPool, 1);
  43 OSMetaClassDefineReservedUnused(IOCommandPool, 2);
  44 OSMetaClassDefineReservedUnused(IOCommandPool, 3);
  45 OSMetaClassDefineReservedUnused(IOCommandPool, 4);
  46 OSMetaClassDefineReservedUnused(IOCommandPool, 5);
  47 OSMetaClassDefineReservedUnused(IOCommandPool, 6);
  48 OSMetaClassDefineReservedUnused(IOCommandPool, 7);
  49
  50 //--------------------------------------------------------------------------
  51 //      withWorkLoop -  primary initializer and factory method
  52 //--------------------------------------------------------------------------
  53
  54 IOCommandPool *IOCommandPool::
  55 withWorkLoop(IOWorkLoop *inWorkLoop)
  56 {
  57     IOCommandPool * me = new IOCommandPool;
  58
  59     if (me && !me->initWithWorkLoop(inWorkLoop)) {
  60         me->release();
  61         return 0;
  62     }
  63
  64     return me;
  65 }
  66
  67
  68 bool IOCommandPool::
  69 initWithWorkLoop(IOWorkLoop *inWorkLoop)
  70 {
  71     assert(inWorkLoop);
  72
  73     if (!super::init())
  74         return false;
  75
  76     queue_init(&fQueueHead);
  77
  78     fSerializer = IOCommandGate::commandGate(this);
  79     assert(fSerializer);
  80     if (!fSerializer)
  81         return false;
  82
  83     if (kIOReturnSuccess != inWorkLoop->addEventSource(fSerializer))
  84         return false;
  85
  86     return true;
  87 }
  88
  89 //--------------------------------------------------------------------------
  90 //      commandPool & init -    obsolete initializer and factory method
  91 //--------------------------------------------------------------------------
  92
  93 IOCommandPool *IOCommandPool::
  94 commandPool(IOService * inOwner, IOWorkLoop *inWorkLoop, UInt32 inSize)
  95 {
  96     IOCommandPool * me = new IOCommandPool;
  97
  98     if (me && !me->init(inOwner, inWorkLoop, inSize)) {
  99         me->release();
 100         return 0;
 101     }
 102
 103     return me;
 104 }
 105
 106 bool IOCommandPool::
 107 init(IOService */* inOwner */, IOWorkLoop *inWorkLoop, UInt32 /* inSize */)
 108 {
 109     return initWithWorkLoop(inWorkLoop);
 110 }
 111
 112
 113 //--------------------------------------------------------------------------
 114 //      free -  free all allocated resources
 115 //--------------------------------------------------------------------------
 116
 117 void
 118 IOCommandPool::free(void)
 119 {
 120     if (fSerializer) {
 121         // remove our event source from owner's workloop
 122         IOWorkLoop *wl = fSerializer->getWorkLoop();
 123         if (wl)
 124             wl->removeEventSource(fSerializer);
 125
 126         fSerializer->release();
 127         fSerializer = 0;
 128     }
 129
 130     // Tell our superclass to cleanup too
 131     super::free();
 132 }
 133
 134
 135 //--------------------------------------------------------------------------
 136 //      getCommand -    Gets a command from the pool. Pass true in
 137 //                      blockForCommand if you want your thread to sleep
 138 //                      waiting for resources
 139 //--------------------------------------------------------------------------
 140
 141 IOCommand *
 142 IOCommandPool::getCommand(bool blockForCommand)
 143 {
 144     IOReturn     result  = kIOReturnSuccess;
 145     IOCommand *command = 0;
 146
 147     result = fSerializer->runAction((IOCommandGate::Action)
 148         &IOCommandPool::gatedGetCommand,
 149             (void *) &command, (void *) blockForCommand);
 150     if (kIOReturnSuccess == result)
 151         return command;
 152     else
 153         return 0;
 154 }
 155
 156
 157 //--------------------------------------------------------------------------
 158 //      gatedGetCommand -       Static callthrough function
 159 //                              (on safe side of command gate)
 160 //--------------------------------------------------------------------------
 161
 162 IOReturn IOCommandPool::
 163 gatedGetCommand(IOCommand **command, bool blockForCommand)
 164 {
 165     while (queue_empty(&fQueueHead)) {
 166         if (!blockForCommand)
 167             return kIOReturnNoResources;
 168
 169         fSleepers++;
 170         fSerializer->commandSleep(&fSleepers, THREAD_UNINT);
 171     }
 172
 173     queue_remove_first(&fQueueHead,
 174                        *command, IOCommand *, fCommandChain);
 175     return kIOReturnSuccess;
 176 }
 177
 178
 179 //--------------------------------------------------------------------------
 180 //      returnCommand -         Returns command to the pool.
 181 //--------------------------------------------------------------------------
 182
 183 void IOCommandPool::
 184 returnCommand(IOCommand *command)
 185 {
 186     (void) fSerializer->runAction((IOCommandGate::Action)
 187         &IOCommandPool::gatedReturnCommand, (void *) command);
 188 }
 189
 190
 191 //--------------------------------------------------------------------------
 192 //      gatedReturnCommand -    Callthrough function
 193 //                              (on safe side of command gate)
 194 //--------------------------------------------------------------------------
 195
 196 IOReturn IOCommandPool::
 197 gatedReturnCommand(IOCommand *command)
 198 {
 199     queue_enter(&fQueueHead, command, IOCommand *, fCommandChain);
 200     if (fSleepers) {
 201         fSerializer->commandWakeup(&fSleepers, /* oneThread */ true);
 202         fSleepers--;
 203     }
 204     return kIOReturnSuccess;
 205 }