iokit/Kernel/IOCommandPool.cpp

   1 /*
   2  * Copyright (c) 2000 Apple Computer, Inc. All rights reserved.
   3  *
   4  * @APPLE_LICENSE_HEADER_START@
   5  *
   6  * The contents of this file constitute Original Code as defined in and
   7  * are subject to the Apple Public Source License Version 1.1 (the
   8  * "License").  You may not use this file except in compliance with the
   9  * License.  Please obtain a copy of the License at
  10  * http://www.apple.com/publicsource and read it before using this file.
  11  *
  12  * This Original Code and all software distributed under the License are
  13  * distributed on an "AS IS" basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  14  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  15  * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
  16  * FITNESS FOR A PARTICULAR PURPOSE OR NON-INFRINGEMENT.  Please see the
  17  * License for the specific language governing rights and limitations
  18  * under the License.
  19  *
  20  * @APPLE_LICENSE_HEADER_END@
  21  */
  22
  23 /*
  24  *
  25  *      Copyright (c) 2000 Apple Computer, Inc.  All rights reserved.
  26  *
  27  *      HISTORY
  28  *
  29  *      2001-01-17      gvdl    Re-implement on IOCommandGate::commandSleep
  30  *      10/9/2000       CJS     Created IOCommandPool class and implementation
  31  *
  32  */
  33
  34 #include <IOKit/IOCommandPool.h>
  35
  36 #define super OSObject
  37 OSDefineMetaClassAndStructors(IOCommandPool, OSObject);
  38 OSMetaClassDefineReservedUnused(IOCommandPool, 0);
  39 OSMetaClassDefineReservedUnused(IOCommandPool, 1);
  40 OSMetaClassDefineReservedUnused(IOCommandPool, 2);
  41 OSMetaClassDefineReservedUnused(IOCommandPool, 3);
  42 OSMetaClassDefineReservedUnused(IOCommandPool, 4);
  43 OSMetaClassDefineReservedUnused(IOCommandPool, 5);
  44 OSMetaClassDefineReservedUnused(IOCommandPool, 6);
  45 OSMetaClassDefineReservedUnused(IOCommandPool, 7);
  46
  47 //--------------------------------------------------------------------------
  48 //      withWorkLoop -  primary initializer and factory method
  49 //--------------------------------------------------------------------------
  50
  51 IOCommandPool *IOCommandPool::
  52 withWorkLoop(IOWorkLoop *inWorkLoop)
  53 {
  54     IOCommandPool * me = new IOCommandPool;
  55
  56     if (me && !me->initWithWorkLoop(inWorkLoop)) {
  57         me->release();
  58         return 0;
  59     }
  60
  61     return me;
  62 }
  63
  64
  65 bool IOCommandPool::
  66 initWithWorkLoop(IOWorkLoop *inWorkLoop)
  67 {
  68     assert(inWorkLoop);
  69
  70     if (!super::init())
  71         return false;
  72
  73     queue_init(&fQueueHead);
  74
  75     fSerializer = IOCommandGate::commandGate(this);
  76     assert(fSerializer);
  77     if (!fSerializer)
  78         return false;
  79
  80     if (kIOReturnSuccess != inWorkLoop->addEventSource(fSerializer))
  81         return false;
  82
  83     return true;
  84 }
  85
  86 //--------------------------------------------------------------------------
  87 //      commandPool & init -    obsolete initializer and factory method
  88 //--------------------------------------------------------------------------
  89
  90 IOCommandPool *IOCommandPool::
  91 commandPool(IOService * inOwner, IOWorkLoop *inWorkLoop, UInt32 inSize)
  92 {
  93     IOCommandPool * me = new IOCommandPool;
  94
  95     if (me && !me->init(inOwner, inWorkLoop, inSize)) {
  96         me->release();
  97         return 0;
  98     }
  99
 100     return me;
 101 }
 102
 103 bool IOCommandPool::
 104 init(IOService */* inOwner */, IOWorkLoop *inWorkLoop, UInt32 /* inSize */)
 105 {
 106     return initWithWorkLoop(inWorkLoop);
 107 }
 108
 109
 110 //--------------------------------------------------------------------------
 111 //      free -  free all allocated resources
 112 //--------------------------------------------------------------------------
 113
 114 void
 115 IOCommandPool::free(void)
 116 {
 117     if (fSerializer) {
 118         // remove our event source from owner's workloop
 119         IOWorkLoop *wl = fSerializer->getWorkLoop();
 120         if (wl)
 121             wl->removeEventSource(fSerializer);
 122
 123         fSerializer->release();
 124         fSerializer = 0;
 125     }
 126
 127     // Tell our superclass to cleanup too
 128     super::free();
 129 }
 130
 131
 132 //--------------------------------------------------------------------------
 133 //      getCommand -    Gets a command from the pool. Pass true in
 134 //                      blockForCommand if you want your thread to sleep
 135 //                      waiting for resources
 136 //--------------------------------------------------------------------------
 137
 138 IOCommand *
 139 IOCommandPool::getCommand(bool blockForCommand)
 140 {
 141     IOReturn     result  = kIOReturnSuccess;
 142     IOCommand *command = 0;
 143
 144     result = fSerializer->runAction((IOCommandGate::Action)
 145         &IOCommandPool::gatedGetCommand,
 146             (void *) &command, (void *) blockForCommand);
 147     if (kIOReturnSuccess == result)
 148         return command;
 149     else
 150         return 0;
 151 }
 152
 153
 154 //--------------------------------------------------------------------------
 155 //      gatedGetCommand -       Static callthrough function
 156 //                              (on safe side of command gate)
 157 //--------------------------------------------------------------------------
 158
 159 IOReturn IOCommandPool::
 160 gatedGetCommand(IOCommand **command, bool blockForCommand)
 161 {
 162     while (queue_empty(&fQueueHead)) {
 163         if (!blockForCommand)
 164             return kIOReturnNoResources;
 165
 166         fSleepers++;
 167         fSerializer->commandSleep(&fSleepers, THREAD_UNINT);
 168     }
 169
 170     queue_remove_first(&fQueueHead,
 171                        *command, IOCommand *, fCommandChain);
 172     return kIOReturnSuccess;
 173 }
 174
 175
 176 //--------------------------------------------------------------------------
 177 //      returnCommand -         Returns command to the pool.
 178 //--------------------------------------------------------------------------
 179
 180 void IOCommandPool::
 181 returnCommand(IOCommand *command)
 182 {
 183     (void) fSerializer->runAction((IOCommandGate::Action)
 184         &IOCommandPool::gatedReturnCommand, (void *) command);
 185 }
 186
 187
 188 //--------------------------------------------------------------------------
 189 //      gatedReturnCommand -    Callthrough function
 190 //                              (on safe side of command gate)
 191 //--------------------------------------------------------------------------
 192
 193 IOReturn IOCommandPool::
 194 gatedReturnCommand(IOCommand *command)
 195 {
 196     queue_enter(&fQueueHead, command, IOCommand *, fCommandChain);
 197     if (fSleepers) {
 198         fSerializer->commandWakeup(&fSleepers, /* oneThread */ true);
 199         fSleepers--;
 200     }
 201     return kIOReturnSuccess;
 202 }