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 #define IOKIT_ENABLE_SHARED_PTR
  41
  42 #include <IOKit/IOCommandPool.h>
  43 #include <libkern/c++/OSSharedPtr.h>
  44
  45 #define super OSObject
  46 OSDefineMetaClassAndStructors(IOCommandPool, OSObject);
  47 OSMetaClassDefineReservedUnused(IOCommandPool, 0);
  48 OSMetaClassDefineReservedUnused(IOCommandPool, 1);
  49 OSMetaClassDefineReservedUnused(IOCommandPool, 2);
  50 OSMetaClassDefineReservedUnused(IOCommandPool, 3);
  51 OSMetaClassDefineReservedUnused(IOCommandPool, 4);
  52 OSMetaClassDefineReservedUnused(IOCommandPool, 5);
  53 OSMetaClassDefineReservedUnused(IOCommandPool, 6);
  54 OSMetaClassDefineReservedUnused(IOCommandPool, 7);
  55
  56 //--------------------------------------------------------------------------
  57 //      withWorkLoop -  primary initializer and factory method
  58 //--------------------------------------------------------------------------
  59
  60 OSSharedPtr<IOCommandPool>
  61 IOCommandPool::
  62 withWorkLoop(IOWorkLoop *inWorkLoop)
  63 {
  64         OSSharedPtr<IOCommandPool> me = OSMakeShared<IOCommandPool>();
  65
  66         if (me && !me->initWithWorkLoop(inWorkLoop)) {
  67                 return nullptr;
  68         }
  69
  70         return me;
  71 }
  72
  73
  74 bool
  75 IOCommandPool::
  76 initWithWorkLoop(IOWorkLoop *inWorkLoop)
  77 {
  78         assert(inWorkLoop);
  79
  80         if (!super::init()) {
  81                 return false;
  82         }
  83
  84         queue_init(&fQueueHead);
  85
  86         fSerializer = IOCommandGate::commandGate(this);
  87         assert(fSerializer);
  88         if (!fSerializer) {
  89                 return false;
  90         }
  91
  92         if (kIOReturnSuccess != inWorkLoop->addEventSource(fSerializer.get())) {
  93                 return false;
  94         }
  95
  96         return true;
  97 }
  98
  99 //--------------------------------------------------------------------------
 100 //      commandPool & init -    obsolete initializer and factory method
 101 //--------------------------------------------------------------------------
 102
 103 OSSharedPtr<IOCommandPool>
 104 IOCommandPool::
 105 commandPool(IOService * inOwner, IOWorkLoop *inWorkLoop, UInt32 inSize)
 106 {
 107         OSSharedPtr<IOCommandPool> me = OSMakeShared<IOCommandPool>();
 108
 109         if (me && !me->init(inOwner, inWorkLoop, inSize)) {
 110                 return nullptr;
 111         }
 112
 113         return me;
 114 }
 115
 116 bool
 117 IOCommandPool::
 118 init(IOService */* inOwner */, IOWorkLoop *inWorkLoop, UInt32 /* inSize */)
 119 {
 120         return initWithWorkLoop(inWorkLoop);
 121 }
 122
 123
 124 //--------------------------------------------------------------------------
 125 //      free -  free all allocated resources
 126 //--------------------------------------------------------------------------
 127
 128 void
 129 IOCommandPool::free(void)
 130 {
 131         if (fSerializer) {
 132                 // remove our event source from owner's workloop
 133                 IOWorkLoop *wl = fSerializer->getWorkLoop();
 134                 if (wl) {
 135                         wl->removeEventSource(fSerializer.get());
 136                 }
 137
 138                 fSerializer.reset();
 139         }
 140
 141         // Tell our superclass to cleanup too
 142         super::free();
 143 }
 144
 145
 146 //--------------------------------------------------------------------------
 147 //      getCommand -    Gets a command from the pool. Pass true in
 148 //                      blockForCommand if you want your thread to sleep
 149 //                      waiting for resources
 150 //--------------------------------------------------------------------------
 151
 152 OSSharedPtr<IOCommand>
 153 IOCommandPool::getCommand(bool blockForCommand)
 154 {
 155         IOReturn     result  = kIOReturnSuccess;
 156         IOCommand *command = NULL;
 157
 158         IOCommandGate::Action func = OSMemberFunctionCast(
 159                 IOCommandGate::Action, this, &IOCommandPool::gatedGetCommand);
 160         result = fSerializer->
 161             runAction(func, (void *) &command, (void *) blockForCommand);
 162         if (kIOReturnSuccess == result) {
 163                 return OSSharedPtr<IOCommand>(command, OSNoRetain);
 164         } else {
 165                 return NULL;
 166         }
 167 }
 168
 169
 170 //--------------------------------------------------------------------------
 171 //      gatedGetCommand -       Static callthrough function
 172 //                              (on safe side of command gate)
 173 //--------------------------------------------------------------------------
 174
 175 IOReturn
 176 IOCommandPool::
 177 gatedGetCommand(IOCommand **command, bool blockForCommand)
 178 {
 179         while (queue_empty(&fQueueHead)) {
 180                 if (!blockForCommand) {
 181                         return kIOReturnNoResources;
 182                 }
 183
 184                 fSleepers++;
 185                 fSerializer->commandSleep(&fSleepers, THREAD_UNINT);
 186         }
 187
 188         queue_remove_first(&fQueueHead,
 189             *command, IOCommand *, fCommandChain);
 190         return kIOReturnSuccess;
 191 }
 192
 193
 194 //--------------------------------------------------------------------------
 195 //      returnCommand -         Returns command to the pool.
 196 //--------------------------------------------------------------------------
 197
 198 void
 199 IOCommandPool::
 200 returnCommand(IOCommand *command)
 201 {
 202         IOCommandGate::Action func = OSMemberFunctionCast(
 203                 IOCommandGate::Action, this, &IOCommandPool::gatedReturnCommand);
 204         (void) fSerializer->runAction(func, (void *) command);
 205 }
 206
 207
 208 //--------------------------------------------------------------------------
 209 //      gatedReturnCommand -    Callthrough function
 210 //                              (on safe side of command gate)
 211 //--------------------------------------------------------------------------
 212
 213 IOReturn
 214 IOCommandPool::
 215 gatedReturnCommand(IOCommand *command)
 216 {
 217         queue_enter_first(&fQueueHead, command, IOCommand *, fCommandChain);
 218         if (fSleepers) {
 219                 fSerializer->commandWakeup(&fSleepers, /* oneThread */ true);
 220                 fSleepers--;
 221         }
 222         return kIOReturnSuccess;
 223 }