xnu-6153.41.3.tar.gz

[apple/xnu.git] / iokit / Kernel / IOWorkLoop.cpp

diff --git a/iokit/Kernel/IOWorkLoop.cpp b/iokit/Kernel/IOWorkLoop.cpp
index f2c11d9486da297fb715d8dddab212b631a771ef..d046938d2aa690f549472f9a73b348225031cbf9 100644 (file)
--- a/iokit/Kernel/IOWorkLoop.cpp
+++ b/iokit/Kernel/IOWorkLoop.cpp
@@ -1,8 +1,8 @@
 /*
 /*

- * Copyright (c) 1998-2000 Apple Computer, Inc. All rights reserved.
+ * Copyright (c) 1998-2010 Apple Inc. All rights reserved.

  *
  * @APPLE_OSREFERENCE_LICENSE_HEADER_START@
  *
  * @APPLE_OSREFERENCE_LICENSE_HEADER_START@

- * 
+ *

  * This file contains Original Code and/or Modifications of Original Code
  * as defined in and that are subject to the Apple Public Source License
  * Version 2.0 (the 'License'). You may not use this file except in
  * This file contains Original Code and/or Modifications of Original Code
  * as defined in and that are subject to the Apple Public Source License
  * Version 2.0 (the 'License'). You may not use this file except in


@@ -11,10 +11,10 @@
  * unlawful or unlicensed copies of an Apple operating system, or to
  * circumvent, violate, or enable the circumvention or violation of, any
  * terms of an Apple operating system software license agreement.
  * unlawful or unlicensed copies of an Apple operating system, or to
  * circumvent, violate, or enable the circumvention or violation of, any
  * terms of an Apple operating system software license agreement.

- * 
+ *

  * Please obtain a copy of the License at
  * http://www.opensource.apple.com/apsl/ and read it before using this file.
  * Please obtain a copy of the License at
  * http://www.opensource.apple.com/apsl/ and read it before using this file.

- * 
+ *

  * The Original Code and all software distributed under the License are
  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
  * The Original Code and all software distributed under the License are
  * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
  * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,


@@ -22,31 +22,35 @@
  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  * Please see the License for the specific language governing rights and
  * limitations under the License.
  * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
  * Please see the License for the specific language governing rights and
  * limitations under the License.

- * 
+ *

  * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
  */
  * @APPLE_OSREFERENCE_LICENSE_HEADER_END@
  */

-/*
-Copyright (c) 1998 Apple Computer, Inc.  All rights reserved.

 
 

-HISTORY
-    1998-7-13  Godfrey van der Linden(gvdl)
-        Created.
-*/
+#include <pexpert/pexpert.h>

 #include <IOKit/IOWorkLoop.h>
 #include <IOKit/IOEventSource.h>
 #include <IOKit/IOInterruptEventSource.h>
 #include <IOKit/IOCommandGate.h>
 #include <IOKit/IOWorkLoop.h>
 #include <IOKit/IOEventSource.h>
 #include <IOKit/IOInterruptEventSource.h>
 #include <IOKit/IOCommandGate.h>

+#include <IOKit/IOCommandPool.h>

 #include <IOKit/IOTimeStamp.h>
 #include <IOKit/IOTimeStamp.h>

+#include <IOKit/IOKitDebug.h>
+#include <libkern/OSDebug.h>
+#include <kern/thread.h>

 
 #define super OSObject
 
 OSDefineMetaClassAndStructors(IOWorkLoop, OSObject);
 
 // Block of unused functions intended for future use
 
 #define super OSObject
 
 OSDefineMetaClassAndStructors(IOWorkLoop, OSObject);
 
 // Block of unused functions intended for future use

-OSMetaClassDefineReservedUsed(IOWorkLoop, 0);
-
+#if __LP64__
+OSMetaClassDefineReservedUnused(IOWorkLoop, 0);

 OSMetaClassDefineReservedUnused(IOWorkLoop, 1);
 OSMetaClassDefineReservedUnused(IOWorkLoop, 2);
 OSMetaClassDefineReservedUnused(IOWorkLoop, 1);
 OSMetaClassDefineReservedUnused(IOWorkLoop, 2);

+#else
+OSMetaClassDefineReservedUsed(IOWorkLoop, 0);
+OSMetaClassDefineReservedUsed(IOWorkLoop, 1);
+OSMetaClassDefineReservedUsed(IOWorkLoop, 2);
+#endif

 OSMetaClassDefineReservedUnused(IOWorkLoop, 3);
 OSMetaClassDefineReservedUnused(IOWorkLoop, 4);
 OSMetaClassDefineReservedUnused(IOWorkLoop, 5);
 OSMetaClassDefineReservedUnused(IOWorkLoop, 3);
 OSMetaClassDefineReservedUnused(IOWorkLoop, 4);
 OSMetaClassDefineReservedUnused(IOWorkLoop, 5);


@@ -54,384 +58,688 @@ OSMetaClassDefineReservedUnused(IOWorkLoop, 6);
 OSMetaClassDefineReservedUnused(IOWorkLoop, 7);
 
 enum IOWorkLoopState { kLoopRestart = 0x1, kLoopTerminate = 0x2 };
 OSMetaClassDefineReservedUnused(IOWorkLoop, 7);
 
 enum IOWorkLoopState { kLoopRestart = 0x1, kLoopTerminate = 0x2 };

-static inline void SETP(void *addr, unsigned int flag)
-    { unsigned int *num = (unsigned int *) addr; *num |= flag; }
-static inline void CLRP(void *addr, unsigned int flag)
-    { unsigned int *num = (unsigned int *) addr; *num &= ~flag; }
-static inline bool ISSETP(void *addr, unsigned int flag)
-    { unsigned int *num = (unsigned int *) addr; return (*num & flag) != 0; }
+static inline void
+SETP(void *addr, unsigned int flag)
+{
+       unsigned char *num = (unsigned char *) addr; *num |= flag;
+}
+static inline void
+CLRP(void *addr, unsigned int flag)
+{
+       unsigned char *num = (unsigned char *) addr; *num &= ~flag;
+}
+static inline bool
+ISSETP(void *addr, unsigned int flag)
+{
+       unsigned char *num = (unsigned char *) addr; return (*num & flag) != 0;
+}

 
 #define fFlags loopRestart
 
 
 #define fFlags loopRestart
 

-bool IOWorkLoop::init()
-{
-    // The super init and gateLock allocation MUST be done first
-    if ( !super::init() )
-        return false;
-
-    if ( !(gateLock = IORecursiveLockAlloc()) )
-        return false;
+#define passiveEventChain       reserved->passiveEventChain

 
 

-    if ( !(workToDoLock = IOSimpleLockAlloc()) )
-        return false;
+#if IOKITSTATS

 
 

-    controlG = IOCommandGate::
-       commandGate(this, (IOCommandGate::Action) &IOWorkLoop::_maintRequest);
-    if ( !controlG )
-        return false;
+#define IOStatisticsRegisterCounter() \
+do { \
+       reserved->counter = IOStatistics::registerWorkLoop(this); \
+} while(0)

 
 

-    IOSimpleLockInit(workToDoLock);
-    workToDo = false;
+#define IOStatisticsUnregisterCounter() \
+do { \
+       if (reserved) \
+               IOStatistics::unregisterWorkLoop(reserved->counter); \
+} while(0)

 
 

-    // Point the controlGate at the workLoop.  Usually addEventSource
-    // does this automatically.  The problem is in this case addEventSource
-    // uses the control gate and it has to be bootstrapped.
-    controlG->setWorkLoop(this);
-    if (addEventSource(controlG) != kIOReturnSuccess)
-        return false;
+#define IOStatisticsOpenGate() \
+do { \
+       IOStatistics::countWorkLoopOpenGate(reserved->counter); \
+       if (reserved->lockInterval) lockTime();                 \
+} while(0)
+#define IOStatisticsCloseGate() \
+do { \
+       IOStatistics::countWorkLoopCloseGate(reserved->counter);                    \
+       if (reserved->lockInterval) reserved->lockTime = mach_absolute_time();      \
+} while(0)

 
 

-    workThread = IOCreateThread((thread_continue_t)threadMainContinuation, this);
-    if (!workThread)
-        return false;
+#define IOStatisticsAttachEventSource() \
+do { \
+       IOStatistics::attachWorkLoopEventSource(reserved->counter, inEvent->reserved->counter); \
+} while(0)

 
 

-    return true;
-}
+#define IOStatisticsDetachEventSource() \
+do { \
+       IOStatistics::detachWorkLoopEventSource(reserved->counter, inEvent->reserved->counter); \
+} while(0)

 
 

-IOWorkLoop *
-IOWorkLoop::workLoop()
-{
-    IOWorkLoop *me = new IOWorkLoop;
+#else

 
 

-    if (me && !me->init()) {
-        me->release();
-        return 0;
-    }
+#define IOStatisticsRegisterCounter()
+#define IOStatisticsUnregisterCounter()
+#define IOStatisticsOpenGate()
+#define IOStatisticsCloseGate()
+#define IOStatisticsAttachEventSource()
+#define IOStatisticsDetachEventSource()

 
 

-    return me;
-}
+#endif /* IOKITSTATS */

 
 

-// Free is called twice:
-// First when the atomic retainCount transitions from 1 -> 0
-// Secondly when the work loop itself is commiting hari kari
-// Hence the each leg of the free must be single threaded.
-void IOWorkLoop::free()
+bool
+IOWorkLoop::init()

 {
 {

-    if (workThread) {
-       IOInterruptState is;
+       // The super init and gateLock allocation MUST be done first.
+       if (!super::init()) {
+               return false;
+       }

 
 

-       // If we are here then we must be trying to shut down this work loop
-       // in this case disable all of the event source, mark the loop for
-       // as terminating and wakeup the work thread itself and return
-       // Note: we hold the gate across the entire operation mainly for the 
-       // benefit of our event sources so we can disable them cleanly.
-       closeGate();
+       // Allocate our ExpansionData if it hasn't been allocated already.
+       if (!reserved) {
+               reserved = IONew(ExpansionData, 1);
+               if (!reserved) {
+                       return false;
+               }

 
 

-       disableAllEventSources();
+               bzero(reserved, sizeof(ExpansionData));
+       }

 
 

-        is = IOSimpleLockLockDisableInterrupt(workToDoLock);
-       SETP(&fFlags, kLoopTerminate);
-        thread_wakeup_one((void *) &workToDo);
-        IOSimpleLockUnlockEnableInterrupt(workToDoLock, is);
+       if (gateLock == NULL) {
+               if (!(gateLock = IORecursiveLockAlloc())) {
+                       return false;
+               }
+       }

 
 

-       openGate();
-    }
-    else /* !workThread */ {
-        IOEventSource *event, *next;
-
-        for (event = eventChain; event; event = next) {
-            next = event->getNext();
-            event->setWorkLoop(0);
-            event->setNext(0);
-            event->release();
-        }
-        eventChain = 0;
-
-       // Either we have a partial initialisation to clean up
-       // or we the workThread itself is performing hari-kari.
-       // either way clean up all of our resources and return.
-       
-       if (controlG) {
-           controlG->release();
-           controlG = 0;
+       if (workToDoLock == NULL) {
+               if (!(workToDoLock = IOSimpleLockAlloc())) {
+                       return false;
+               }
+               IOSimpleLockInit(workToDoLock);
+               workToDo = false;

        }
 
        }
 

-       if (workToDoLock) {
-           IOSimpleLockFree(workToDoLock);
-           workToDoLock = 0;
+       IOStatisticsRegisterCounter();
+
+       if (controlG == NULL) {
+               controlG = IOCommandGate::commandGate(
+                       this,
+                       OSMemberFunctionCast(
+                               IOCommandGate::Action,
+                               this,
+                               &IOWorkLoop::_maintRequest));
+
+               if (!controlG) {
+                       return false;
+               }
+               // Point the controlGate at the workLoop.  Usually addEventSource
+               // does this automatically.  The problem is in this case addEventSource
+               // uses the control gate and it has to be bootstrapped.
+               controlG->setWorkLoop(this);
+               if (addEventSource(controlG) != kIOReturnSuccess) {
+                       return false;
+               }

        }
 
        }
 

-       if (gateLock) {
-           IORecursiveLockFree(gateLock);
-           gateLock = 0;
+       if (workThread == NULL) {
+               thread_continue_t cptr = OSMemberFunctionCast(
+                       thread_continue_t,
+                       this,
+                       &IOWorkLoop::threadMain);
+               if (KERN_SUCCESS != kernel_thread_start(cptr, this, &workThread)) {
+                       return false;
+               }

        }
 
        }
 

-       super::free();
-    }
+       (void) thread_set_tag(workThread, THREAD_TAG_IOWORKLOOP);
+       return true;

 }
 
 }
 

-IOReturn IOWorkLoop::addEventSource(IOEventSource *newEvent)
-{
-    return controlG->runCommand((void *) mAddEvent, (void *) newEvent);
-}
-    
-IOReturn IOWorkLoop::removeEventSource(IOEventSource *toRemove)
+IOWorkLoop *
+IOWorkLoop::workLoop()

 {
 {

-    return controlG->runCommand((void *) mRemoveEvent, (void *) toRemove);
+       return IOWorkLoop::workLoopWithOptions(0);

 }
 
 }
 

-void IOWorkLoop::enableAllEventSources() const
+IOWorkLoop *
+IOWorkLoop::workLoopWithOptions(IOOptionBits options)

 {
 {

-    IOEventSource *event;
+       IOWorkLoop *me = new IOWorkLoop;
+
+       if (me && options) {
+               me->reserved = IONew(ExpansionData, 1);
+               if (!me->reserved) {
+                       me->release();
+                       return NULL;
+               }
+               bzero(me->reserved, sizeof(ExpansionData));
+               me->reserved->options = options;
+       }
+
+       if (me && !me->init()) {
+               me->release();
+               return NULL;
+       }

 
 

-    for (event = eventChain; event; event = event->getNext())
-        event->enable();
+       return me;

 }
 
 }
 

-void IOWorkLoop::disableAllEventSources() const
+// Free is called twice:
+// First when the atomic retainCount transitions from 1 -> 0
+// Secondly when the work loop itself is commiting hari kari
+// Hence the each leg of the free must be single threaded.
+void
+IOWorkLoop::free()

 {
 {

-    IOEventSource *event;
-
-    for (event = eventChain; event; event = event->getNext())
-        if (event != controlG) // Don't disable the control gate
-            event->disable();
+       if (workThread) {
+               IOInterruptState is;
+
+               // If we are here then we must be trying to shut down this work loop
+               // in this case disable all of the event source, mark the loop
+               // as terminating and wakeup the work thread itself and return
+               // Note: we hold the gate across the entire operation mainly for the
+               // benefit of our event sources so we can disable them cleanly.
+               closeGate();
+
+               disableAllEventSources();
+
+               is = IOSimpleLockLockDisableInterrupt(workToDoLock);
+               SETP(&fFlags, kLoopTerminate);
+               thread_wakeup_thread((void *) &workToDo, workThread);
+               IOSimpleLockUnlockEnableInterrupt(workToDoLock, is);
+
+               openGate();
+       } else { /* !workThread */
+               IOEventSource *event, *next;
+
+               for (event = eventChain; event; event = next) {
+                       next = event->getNext();
+                       event->setWorkLoop(NULL);
+                       event->setNext(NULL);
+                       event->release();
+               }
+               eventChain = NULL;
+
+               for (event = passiveEventChain; event; event = next) {
+                       next = event->getNext();
+                       event->setWorkLoop(NULL);
+                       event->setNext(NULL);
+                       event->release();
+               }
+               passiveEventChain = NULL;
+
+               // Either we have a partial initialization to clean up
+               // or the workThread itself is performing hari-kari.
+               // Either way clean up all of our resources and return.
+
+               if (controlG) {
+                       controlG->workLoop = NULL;
+                       controlG->release();
+                       controlG = NULL;
+               }
+
+               if (workToDoLock) {
+                       IOSimpleLockFree(workToDoLock);
+                       workToDoLock = NULL;
+               }
+
+               if (gateLock) {
+                       IORecursiveLockFree(gateLock);
+                       gateLock = NULL;
+               }
+
+               IOStatisticsUnregisterCounter();
+
+               if (reserved) {
+                       IODelete(reserved, ExpansionData, 1);
+                       reserved = NULL;
+               }
+
+               super::free();
+       }

 }
 
 }
 

-void IOWorkLoop::enableAllInterrupts() const
+IOReturn
+IOWorkLoop::addEventSource(IOEventSource *newEvent)

 {
 {

-    IOEventSource *event;
+       if ((workThread)
+           && !thread_has_thread_name(workThread)
+           && (newEvent->owner)
+           && !OSDynamicCast(IOCommandPool, newEvent->owner)) {
+               thread_set_thread_name(workThread, newEvent->owner->getMetaClass()->getClassName());
+       }

 
 

-    for (event = eventChain; event; event = event->getNext())
-        if (OSDynamicCast(IOInterruptEventSource, event))
-            event->enable();
+       return controlG->runCommand((void *) mAddEvent, (void *) newEvent);

 }
 
 }
 

-void IOWorkLoop::disableAllInterrupts() const
+IOReturn
+IOWorkLoop::removeEventSource(IOEventSource *toRemove)

 {
 {

-    IOEventSource *event;
-
-    for (event = eventChain; event; event = event->getNext())
-        if (OSDynamicCast(IOInterruptEventSource, event))
-            event->disable();
+       return controlG->runCommand((void *) mRemoveEvent, (void *) toRemove);

 }
 
 }
 

-#if KDEBUG
-#define IOTimeClientS()                                                        \
-do {                                                                   \
-    IOTimeStampStart(IODBG_WORKLOOP(IOWL_CLIENT),                      \
-                     (unsigned int) this, (unsigned int) event);       \
-} while(0)
-
-#define IOTimeClientE()                                                        \
-do {                                                                   \
-    IOTimeStampEnd(IODBG_WORKLOOP(IOWL_CLIENT),                                \
-                   (unsigned int) this, (unsigned int) event);         \
-} while(0)
+void
+IOWorkLoop::enableAllEventSources() const
+{
+       IOEventSource *event;

 
 

-#define IOTimeWorkS()                                                  \
-do {                                                                   \
-    IOTimeStampStart(IODBG_WORKLOOP(IOWL_WORK),        (unsigned int) this);   \
-} while(0)
+       for (event = eventChain; event; event = event->getNext()) {
+               event->enable();
+       }

 
 

-#define IOTimeWorkE()                                                  \
-do {                                                                   \
-    IOTimeStampEnd(IODBG_WORKLOOP(IOWL_WORK),(unsigned int) this);     \
-} while(0)
+       for (event = passiveEventChain; event; event = event->getNext()) {
+               event->enable();
+       }
+}

 
 

-#else /* !KDEBUG */
+void
+IOWorkLoop::disableAllEventSources() const
+{
+       IOEventSource *event;

 
 

-#define IOTimeClientS()
-#define IOTimeClientE()
-#define IOTimeWorkS()
-#define IOTimeWorkE()
+       for (event = eventChain; event; event = event->getNext()) {
+               event->disable();
+       }

 
 

-#endif /* KDEBUG */
+       /* NOTE: controlG is in passiveEventChain since it's an IOCommandGate */
+       for (event = passiveEventChain; event; event = event->getNext()) {
+               if (event != controlG) { // Don't disable the control gate
+                       event->disable();
+               }
+       }
+}

 
 

-void IOWorkLoop::threadMainContinuation(IOWorkLoop *self)
+void
+IOWorkLoop::enableAllInterrupts() const

 {
 {

-       self->threadMain();
+       IOEventSource *event;
+
+       for (event = eventChain; event; event = event->getNext()) {
+               if (OSDynamicCast(IOInterruptEventSource, event)) {
+                       event->enable();
+               }
+       }

 }
 
 }
 

-void IOWorkLoop::threadMain()
+void
+IOWorkLoop::disableAllInterrupts() const

 {
 {

-    CLRP(&fFlags, kLoopRestart);
+       IOEventSource *event;

 
 

-    for (;;) {
-        bool more;
-       IOInterruptState is;
-
-    IOTimeWorkS();
+       for (event = eventChain; event; event = event->getNext()) {
+               if (OSDynamicCast(IOInterruptEventSource, event)) {
+                       event->disable();
+               }
+       }
+}

 
 

-        closeGate();
-        if (ISSETP(&fFlags, kLoopTerminate))
-           goto exitThread;

 
 

-        do {
-            workToDo = more = false;
-            for (IOEventSource *event = eventChain; event; event = event->getNext()) {
+/* virtual */ bool
+IOWorkLoop::runEventSources()
+{
+       bool res = false;
+       bool traceWL = (gIOKitTrace & kIOTraceWorkLoops) ? true : false;
+       bool traceES = (gIOKitTrace & kIOTraceEventSources) ? true : false;

 
 

-            IOTimeClientS();
-                more |= event->checkForWork();
-            IOTimeClientE();
+       closeGate();
+       if (ISSETP(&fFlags, kLoopTerminate)) {
+               goto abort;
+       }

 
 

-               if (ISSETP(&fFlags, kLoopTerminate))
-                   goto exitThread;
-                else if (fFlags & kLoopRestart) {
-                   CLRP(&fFlags, kLoopRestart);
-                    continue;
-                }
-            }
-        } while (more);
+       if (traceWL) {
+               IOTimeStampStartConstant(IODBG_WORKLOOP(IOWL_WORK), VM_KERNEL_ADDRHIDE(this));
+       }

 
 

-    IOTimeWorkE();
+       bool more;
+       do {
+               CLRP(&fFlags, kLoopRestart);
+               more = false;
+               IOInterruptState is = IOSimpleLockLockDisableInterrupt(workToDoLock);
+               workToDo = false;
+               IOSimpleLockUnlockEnableInterrupt(workToDoLock, is);
+               /* NOTE: only loop over event sources in eventChain. Bypass "passive" event sources for performance */
+               for (IOEventSource *evnt = eventChain; evnt; evnt = evnt->getNext()) {
+                       if (traceES) {
+                               IOTimeStampStartConstant(IODBG_WORKLOOP(IOWL_CLIENT), VM_KERNEL_ADDRHIDE(this), VM_KERNEL_ADDRHIDE(evnt));
+                       }
+
+                       more |= evnt->checkForWork();
+
+                       if (traceES) {
+                               IOTimeStampEndConstant(IODBG_WORKLOOP(IOWL_CLIENT), VM_KERNEL_ADDRHIDE(this), VM_KERNEL_ADDRHIDE(evnt));
+                       }
+
+                       if (ISSETP(&fFlags, kLoopTerminate)) {
+                               goto abort;
+                       } else if (fFlags & kLoopRestart) {
+                               more = true;
+                               break;
+                       }
+               }
+       } while (more);
+
+       res = true;
+
+       if (traceWL) {
+               IOTimeStampEndConstant(IODBG_WORKLOOP(IOWL_WORK), VM_KERNEL_ADDRHIDE(this));
+       }

 
 

-        openGate();
+abort:
+       openGate();
+       return res;
+}

 
 

-       is = IOSimpleLockLockDisableInterrupt(workToDoLock);
-        if ( !ISSETP(&fFlags, kLoopTerminate) && !workToDo) {
-           assert_wait((void *) &workToDo, false);
-           IOSimpleLockUnlockEnableInterrupt(workToDoLock, is);
+/* virtual */ void
+IOWorkLoop::threadMain()
+{
+restartThread:
+       do {
+               if (!runEventSources()) {
+                       goto exitThread;
+               }
+
+               IOInterruptState is = IOSimpleLockLockDisableInterrupt(workToDoLock);
+               if (!ISSETP(&fFlags, kLoopTerminate) && !workToDo) {
+                       assert_wait((void *) &workToDo, false);
+                       IOSimpleLockUnlockEnableInterrupt(workToDoLock, is);
+                       thread_continue_t cptr = NULL;
+                       if (!reserved || !(kPreciousStack & reserved->options)) {
+                               cptr = OSMemberFunctionCast(
+                                       thread_continue_t, this, &IOWorkLoop::threadMain);
+                       }
+                       thread_block_parameter(cptr, this);
+                       goto restartThread;
+                       /* NOTREACHED */
+               }
+
+               // At this point we either have work to do or we need
+               // to commit suicide.  But no matter
+               // Clear the simple lock and retore the interrupt state
+               IOSimpleLockUnlockEnableInterrupt(workToDoLock, is);
+       } while (workToDo);

 
 

-           thread_block_parameter((thread_continue_t)threadMainContinuation, this);
-           /* NOTREACHED */
-       }
+exitThread:
+       closeGate();
+       thread_t thread = workThread;
+       workThread = NULL; // Say we don't have a loop and free ourselves
+       openGate();

 
 

-       // At this point we either have work to do or we need
-       // to commit suicide.  But no matter 
-       // Clear the simple lock and retore the interrupt state
-       IOSimpleLockUnlockEnableInterrupt(workToDoLock, is);
-       if (workToDo)
-           continue;
-       else
-           break;
-    }
+       free();

 
 

-exitThread:
-    workThread = 0;    // Say we don't have a loop and free ourselves
-    free();
-    IOExitThread();
+       thread_deallocate(thread);
+       (void) thread_terminate(thread);

 }
 
 }
 

-IOThread IOWorkLoop::getThread() const
+IOThread
+IOWorkLoop::getThread() const

 {
 {

-    return workThread;
+       return workThread;

 }
 
 }
 

-bool IOWorkLoop::onThread() const
+bool
+IOWorkLoop::onThread() const

 {
 {

-    return (IOThreadSelf() == workThread);
+       return IOThreadSelf() == workThread;

 }
 
 }
 

-bool IOWorkLoop::inGate() const
+bool
+IOWorkLoop::inGate() const

 {
 {

-    return IORecursiveLockHaveLock(gateLock);
+       return IORecursiveLockHaveLock(gateLock);

 }
 
 // Internal APIs used by event sources to control the thread
 }
 
 // Internal APIs used by event sources to control the thread

-void IOWorkLoop::signalWorkAvailable()
+void
+IOWorkLoop::signalWorkAvailable()
+{
+       if (workToDoLock) {
+               IOInterruptState is = IOSimpleLockLockDisableInterrupt(workToDoLock);
+               workToDo = true;
+               thread_wakeup_thread((void *) &workToDo, workThread);
+               IOSimpleLockUnlockEnableInterrupt(workToDoLock, is);
+       }
+}
+
+void
+IOWorkLoop::openGate()
+{
+       IOStatisticsOpenGate();
+       IORecursiveLockUnlock(gateLock);
+}
+
+void
+IOWorkLoop::closeGate()
+{
+       IORecursiveLockLock(gateLock);
+       IOStatisticsCloseGate();
+}
+
+bool
+IOWorkLoop::tryCloseGate()

 {
 {

-    if (workToDoLock) {
-        IOInterruptState is = IOSimpleLockLockDisableInterrupt(workToDoLock);
-        workToDo = true;
-        thread_wakeup_one((void *) &workToDo);
-        IOSimpleLockUnlockEnableInterrupt(workToDoLock, is);
-    }
+       bool res = (IORecursiveLockTryLock(gateLock) != 0);
+       if (res) {
+               IOStatisticsCloseGate();
+       }
+       return res;

 }
 
 }
 

-void IOWorkLoop::openGate()
+int
+IOWorkLoop::sleepGate(void *event, UInt32 interuptibleType)

 {
 {

-    IORecursiveLockUnlock(gateLock);
+       int res;
+       IOStatisticsOpenGate();
+       res = IORecursiveLockSleep(gateLock, event, interuptibleType);
+       IOStatisticsCloseGate();
+       return res;

 }
 
 }
 

-void IOWorkLoop::closeGate()
+int
+IOWorkLoop::sleepGate(void *event, AbsoluteTime deadline, UInt32 interuptibleType)

 {
 {

-    IORecursiveLockLock(gateLock);
+       int res;
+       IOStatisticsOpenGate();
+       res = IORecursiveLockSleepDeadline(gateLock, event, deadline, interuptibleType);
+       IOStatisticsCloseGate();
+       return res;

 }
 
 }
 

-bool IOWorkLoop::tryCloseGate()
+void
+IOWorkLoop::wakeupGate(void *event, bool oneThread)

 {
 {

-    return IORecursiveLockTryLock(gateLock) != 0;
+       IORecursiveLockWakeup(gateLock, event, oneThread);

 }
 
 }
 

-int IOWorkLoop::sleepGate(void *event, UInt32 interuptibleType)
+static IOReturn
+IOWorkLoopActionToBlock(OSObject *owner,
+    void *arg0, void *arg1,
+    void *arg2, void *arg3)

 {
 {

-    return IORecursiveLockSleep(gateLock, event, interuptibleType);
+       return ((IOWorkLoop::ActionBlock) arg0)();

 }
 
 }
 

-void IOWorkLoop::wakeupGate(void *event, bool oneThread)
+IOReturn
+IOWorkLoop::runActionBlock(ActionBlock action)

 {
 {

-    IORecursiveLockWakeup(gateLock, event, oneThread);
+       return runAction(&IOWorkLoopActionToBlock, this, action);

 }
 
 }
 

-IOReturn IOWorkLoop::runAction(Action inAction, OSObject *target,
-                                  void *arg0, void *arg1,
-                                  void *arg2, void *arg3)
+IOReturn
+IOWorkLoop::runAction(Action inAction, OSObject *target,
+    void *arg0, void *arg1,
+    void *arg2, void *arg3)

 {
 {

-    IOReturn res;
+       IOReturn res;

 
 

-    // closeGate is recursive so don't worry if we already hold the lock.
-    closeGate();
-    res = (*inAction)(target, arg0, arg1, arg2, arg3);
-    openGate();
+       // closeGate is recursive so don't worry if we already hold the lock.
+       closeGate();
+       res = (*inAction)(target, arg0, arg1, arg2, arg3);
+       openGate();

 
 

-    return res;
+       return res;

 }
 
 }
 

-IOReturn IOWorkLoop::_maintRequest(void *inC, void *inD, void *, void *)
+IOReturn
+IOWorkLoop::_maintRequest(void *inC, void *inD, void *, void *)

 {
 {

-    maintCommandEnum command = (maintCommandEnum) (vm_address_t) inC;
-    IOEventSource *inEvent = (IOEventSource *) inD;
-    IOReturn res = kIOReturnSuccess;
+       maintCommandEnum command = (maintCommandEnum) (uintptr_t) inC;
+       IOEventSource *inEvent = (IOEventSource *) inD;
+       IOReturn res = kIOReturnSuccess;
+
+       switch (command) {
+       case mAddEvent:
+               if (!inEvent->getWorkLoop()) {
+                       SETP(&fFlags, kLoopRestart);
+
+                       inEvent->retain();
+                       inEvent->setWorkLoop(this);
+                       inEvent->setNext(NULL);
+
+                       /* Check if this is a passive or active event source being added */
+                       if (eventSourcePerformsWork(inEvent)) {
+                               if (!eventChain) {
+                                       eventChain = inEvent;
+                               } else {
+                                       IOEventSource *event, *next;
+
+                                       for (event = eventChain; (next = event->getNext()); event = next) {
+                                               ;
+                                       }
+                                       event->setNext(inEvent);
+                               }
+                       } else {
+                               if (!passiveEventChain) {
+                                       passiveEventChain = inEvent;
+                               } else {
+                                       IOEventSource *event, *next;
+
+                                       for (event = passiveEventChain; (next = event->getNext()); event = next) {
+                                               ;
+                                       }
+                                       event->setNext(inEvent);
+                               }
+                       }
+                       IOStatisticsAttachEventSource();
+               }
+               break;
+
+       case mRemoveEvent:
+               if (inEvent->getWorkLoop()) {
+                       IOStatisticsDetachEventSource();
+
+                       if (eventSourcePerformsWork(inEvent)) {
+                               if (eventChain == inEvent) {
+                                       eventChain = inEvent->getNext();
+                               } else {
+                                       IOEventSource *event, *next = NULL;
+
+                                       event = eventChain;
+                                       if (event) {
+                                               while ((next = event->getNext()) && (next != inEvent)) {
+                                                       event = next;
+                                               }
+                                       }
+
+                                       if (!next) {
+                                               res = kIOReturnBadArgument;
+                                               break;
+                                       }
+                                       event->setNext(inEvent->getNext());
+                               }
+                       } else {
+                               if (passiveEventChain == inEvent) {
+                                       passiveEventChain = inEvent->getNext();
+                               } else {
+                                       IOEventSource *event, *next = NULL;
+
+                                       event = passiveEventChain;
+                                       if (event) {
+                                               while ((next = event->getNext()) && (next != inEvent)) {
+                                                       event = next;
+                                               }
+                                       }
+
+                                       if (!next) {
+                                               res = kIOReturnBadArgument;
+                                               break;
+                                       }
+                                       event->setNext(inEvent->getNext());
+                               }
+                       }
+
+                       inEvent->setWorkLoop(NULL);
+                       inEvent->setNext(NULL);
+                       inEvent->release();
+                       SETP(&fFlags, kLoopRestart);
+               }
+               break;
+
+       default:
+               return kIOReturnUnsupported;
+       }

 
 

-    switch (command)
-    {
-    case mAddEvent:
-        if (!inEvent->getWorkLoop()) {
-            SETP(&fFlags, kLoopRestart);
+       return res;
+}

 
 

-            inEvent->retain();
-            inEvent->setWorkLoop(this);
-            inEvent->setNext(0);
-    
-            if (!eventChain)
-                eventChain = inEvent;
-            else {
-                IOEventSource *event, *next;
-    
-                for (event = eventChain; (next = event->getNext()); event = next)
-                    ;
-                event->setNext(inEvent);
-            }
-        }
-        break;
+bool
+IOWorkLoop::eventSourcePerformsWork(IOEventSource *inEventSource)
+{
+       bool    result = true;
+
+       /*
+        * The idea here is to see if the subclass of IOEventSource has overridden checkForWork().
+        * The assumption is that if you override checkForWork(), you need to be
+        * active and not passive.
+        *
+        * We picked a known quantity controlG that does not override
+        * IOEventSource::checkForWork(), namely the IOCommandGate associated with
+        * the workloop to which this event source is getting attached.
+        *
+        * We do a pointer comparison on the offset in the vtable for inNewEvent against
+        * the offset in the vtable for inReferenceEvent. This works because
+        * IOCommandGate's slot for checkForWork() has the address of
+        * IOEventSource::checkForWork() in it.
+        *
+        * Think of OSMemberFunctionCast yielding the value at the vtable offset for
+        * checkForWork() here. We're just testing to see if it's the same or not.
+        *
+        */
+
+       if (IOEventSource::kPassive & inEventSource->flags) {
+               result = false;
+       } else if (IOEventSource::kActive & inEventSource->flags) {
+               result = true;
+       } else if (controlG) {
+               void *  ptr1;
+               void *  ptr2;
+
+               ptr1 = OSMemberFunctionCast(void*, inEventSource, &IOEventSource::checkForWork);
+               ptr2 = OSMemberFunctionCast(void*, controlG, &IOEventSource::checkForWork);
+
+               if (ptr1 == ptr2) {
+                       result = false;
+               }
+       }

 
 

-    case mRemoveEvent:
-        if (inEvent->getWorkLoop()) {
-            if (eventChain == inEvent)
-                eventChain = inEvent->getNext();
-            else {
-                IOEventSource *event, *next;
-    
-                event = eventChain;
-                while ((next = event->getNext()) && next != inEvent)
-                    event = next;
-    
-                if (!next) {
-                    res = kIOReturnBadArgument;
-                    break;
-                }
-                event->setNext(inEvent->getNext());
-            }
-    
-            inEvent->setWorkLoop(0);
-            inEvent->setNext(0);
-            inEvent->release();
-            SETP(&fFlags, kLoopRestart);
-        }
-        break;
+       return result;
+}

 
 

-    default:
-        return kIOReturnUnsupported;
-    }
+void
+IOWorkLoop::lockTime(void)
+{
+       uint64_t time;
+       time = mach_absolute_time() - reserved->lockTime;
+       if (time > reserved->lockInterval) {
+               absolutetime_to_nanoseconds(time, &time);
+               if (kTimeLockPanics & reserved->options) {
+                       panic("IOWorkLoop %p lock time %qd us", this, time / 1000ULL);
+               } else {
+                       OSReportWithBacktrace("IOWorkLoop %p lock time %qd us", this, time / 1000ULL);
+               }
+       }
+}

 
 

-    return res;
+void
+IOWorkLoop::setMaximumLockTime(uint64_t interval, uint32_t options)
+{
+       IORecursiveLockLock(gateLock);
+       reserved->lockInterval = interval;
+       reserved->options = (reserved->options & ~kTimeLockPanics) | (options & kTimeLockPanics);
+       IORecursiveLockUnlock(gateLock);

 }
 }