1.3.3 Spin Locks and Interlocks

IoAcquireCancelSpinLock: Synchronizes cancelable-state transitions for IRPs in a multiprocessor-safe manner.
IoSetCancelRoutine: Sets or clears the Cancel routine in an IRP during a cancelable state transition. Setting a Cancel routine makes an IRP cancelable.
IoReleaseCancelSpinLock: Releases the cancel spin lock when the driver has changed the cancelable state of an IRP or releases the cancel spin lock from the driver’s Cancel routine.
KeInitializeSpinLock: Initializes a variable of type KSPIN_LOCK, used to synchronize access to data shared among nonISR routines. An initialized spin lock also is a required parameter to the ExInterlockedXxx routines.
KeAcquireSpinLock: Acquires a spin lock so the caller can synchronize access to shared data in a multiprocessor-safe way.
KeReleaseSpinLock: Releases a spin lock that was acquired by calling KeAcquireSpinLock and restores the original IRQL at which the caller was running.
KeAcquireSpinLockAtDpcLevel: Acquires a spin lock, provided that the caller is already running at IRQL DISPATCH_LEVEL.
KeReleaseSpinLockFromDpcLevel: Releases a spin lock that was acquired by calling KeAcquireSpinLockAtDpcLevel.
ExInterlocked..List: Insert and remove IRPs in a driver-managed internal queue, which is protected by an initialized spin lock for which the driver provides the storage.
ExInterlocked..Zone: Allocates and deallocates fixed-size entries, under spin lock control, from a driver-allocated and initialized zone buffer.
Ke..DeviceQueue: Insert and remove IRPs in a driver-allocated and managed internal device queue object, which is protected by a built-in spin lock.
ExInterlockedAddUlong: Adds a value to a variable of type ULONG as an atomic operation, using a spin lock to ensure multiprocessor-safe access to the variable; returns the original (unsummed) value of the variable.
ExInterlockedAddLargeInteger: Adds a value to a variable of type LARGE_INTEGER as an atomic operation, using a spin lock to ensure multiprocessor-safe access to the variable; returns the original (unsummed) value of the variable.
InterlockedIncrement: Increments a variable of type LONG as an atomic operation. The sign of the return value is the sign of the result of the operation.
InterlockedDecrement: Decrements a variable of type LONG as an atomic operation. The sign of the return value is the sign of the result of the operation.
InterlockedExchange: Sets a variable of type LONG to a specified value as an atomic operation; returns the original (unset) value of the variable.
KeGetCurrentProcessorNumber: Returns the current processor number when debugging spin lock usage in SMP machines.