xnu-3789.51.2.tar.gz

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

diff --git a/iokit/Kernel/IOCommandGate.cpp b/iokit/Kernel/IOCommandGate.cpp
index 9b19d70eefeb5e7dd63bfb88997f44401ed9c654..2308daf1b5bf0a67a0699f9c35c0d0dd00fe2b2f 100644 (file)
--- a/iokit/Kernel/IOCommandGate.cpp
+++ b/iokit/Kernel/IOCommandGate.cpp
@@ -111,24 +111,41 @@ IOCommandGate::commandGate(OSObject *inOwner, Action inAction)
 
 /* virtual */ void IOCommandGate::free()
 {
-    setWorkLoop(0);
+    if (workLoop) setWorkLoop(0);
     super::free();
 }
 
+enum
+{
+    kSleepersRemoved     = 0x00000001,
+    kSleepersWaitEnabled = 0x00000002,
+    kSleepersActions     = 0x00000100,
+    kSleepersActionsMask = 0xffffff00,
+};
+
 /* virtual */ void IOCommandGate::setWorkLoop(IOWorkLoop *inWorkLoop)
 {
-    uintptr_t *sleepersP = (uintptr_t *) &reserved;
-    if (!inWorkLoop && workLoop) {             // tearing down
-       closeGate();
-       *sleepersP |= 1;
-       while (*sleepersP >> 1) {
+    IOWorkLoop * wl;
+    uintptr_t  * sleepersP = (uintptr_t *) &reserved;
+    bool         defer;
+
+    if (!inWorkLoop && (wl = workLoop)) {              // tearing down
+       wl->closeGate();
+       *sleepersP |= kSleepersRemoved;
+       while (*sleepersP & kSleepersWaitEnabled) {
            thread_wakeup_with_result(&enabled, THREAD_INTERRUPTED);
            sleepGate(sleepersP, THREAD_UNINT);
        }
-       *sleepersP = 0;
-       openGate();
+       *sleepersP &= ~kSleepersWaitEnabled;
+       defer = (0 != (kSleepersActionsMask & *sleepersP));
+       if (!defer)
+       {
+           super::setWorkLoop(0);
+           *sleepersP &= ~kSleepersRemoved;
+       }
+       wl->openGate();
+       return;
     }
-    else
 
     super::setWorkLoop(inWorkLoop);
 }
@@ -149,29 +166,38 @@ IOReturn IOCommandGate::runAction(Action inAction,
                                   void *arg0, void *arg1,
                                   void *arg2, void *arg3)
 {
+    IOWorkLoop * wl;
+    uintptr_t  * sleepersP;
+
     if (!inAction)
         return kIOReturnBadArgument;
+    if (!(wl = workLoop))
+        return kIOReturnNotReady;
 
     // closeGate is recursive needn't worry if we already hold the lock.
-    closeGate();
+    wl->closeGate();
+    sleepersP = (uintptr_t *) &reserved;
 
     // If the command gate is disabled and we aren't on the workloop thread
     // itself then sleep until we get enabled.
     IOReturn res;
-    if (!workLoop->onThread()) {
-       while (!enabled) {
-           uintptr_t *sleepersP = (uintptr_t *) &reserved;
-
-           *sleepersP += 2;
-           IOReturn res = sleepGate(&enabled, THREAD_ABORTSAFE);
-           *sleepersP -= 2;
-
-           bool wakeupTearDown = (*sleepersP & 1);
-           if (res || wakeupTearDown) {
-               openGate();
+    if (!wl->onThread())
+    {
+       while (!enabled)
+       {
+            IOReturn sleepResult = kIOReturnSuccess;
+           if (workLoop)
+           {
+               *sleepersP |= kSleepersWaitEnabled;
+               sleepResult = wl->sleepGate(&enabled, THREAD_INTERRUPTIBLE);
+               *sleepersP &= ~kSleepersWaitEnabled;
+           }
+           bool wakeupTearDown = (!workLoop || (0 != (*sleepersP & kSleepersRemoved)));
+           if ((kIOReturnSuccess != sleepResult) || wakeupTearDown) {
+               wl->openGate();
 
                 if (wakeupTearDown)
-                    commandWakeup(sleepersP);  // No further resources used
+                    wl->wakeupGate(sleepersP, false);  // No further resources used
 
                return kIOReturnAborted;
            }
@@ -180,20 +206,28 @@ IOReturn IOCommandGate::runAction(Action inAction,
 
     bool trace = ( gIOKitTrace & kIOTraceCommandGates ) ? true : false;
        
-       if (trace)
-               IOTimeStampStartConstant(IODBG_CMDQ(IOCMDQ_ACTION),
+    if (trace) IOTimeStampStartConstant(IODBG_CMDQ(IOCMDQ_ACTION),
                                         VM_KERNEL_UNSLIDE(inAction), (uintptr_t) owner);
        
     IOStatisticsActionCall();
        
     // Must be gated and on the work loop or enabled
+
+    *sleepersP += kSleepersActions;
     res = (*inAction)(owner, arg0, arg1, arg2, arg3);
-       
-       if (trace)
-               IOTimeStampEndConstant(IODBG_CMDQ(IOCMDQ_ACTION),
+    *sleepersP -= kSleepersActions;
+
+    if (trace) IOTimeStampEndConstant(IODBG_CMDQ(IOCMDQ_ACTION),
                                       VM_KERNEL_UNSLIDE(inAction), (uintptr_t) owner);
+
+    if (kSleepersRemoved == ((kSleepersActionsMask|kSleepersRemoved) & *sleepersP))
+    {
+        // no actions outstanding
+       *sleepersP &= ~kSleepersRemoved;
+       super::setWorkLoop(0);
+    }
     
-    openGate();
+    wl->openGate();
        
     return res;
 }
@@ -203,16 +237,19 @@ IOReturn IOCommandGate::attemptAction(Action inAction,
                                       void *arg2, void *arg3)
 {
     IOReturn res;
+    IOWorkLoop * wl;
 
     if (!inAction)
         return kIOReturnBadArgument;
+    if (!(wl = workLoop))
+        return kIOReturnNotReady;
 
     // Try to close the gate if can't get return immediately.
-    if (!tryCloseGate())
+    if (!wl->tryCloseGate())
         return kIOReturnCannotLock;
 
     // If the command gate is disabled then sleep until we get a wakeup
-    if (!workLoop->onThread() && !enabled)
+    if (!wl->onThread() && !enabled)
         res = kIOReturnNotPermitted;
     else {
                
@@ -231,7 +268,7 @@ IOReturn IOCommandGate::attemptAction(Action inAction,
                                   VM_KERNEL_UNSLIDE(inAction), (uintptr_t) owner);
     }
 
-    openGate();
+    wl->openGate();
 
     return res;
 }