The KLOCK_QUEUE_HANDLE structure is an opaque structure that describes a queued spin lock. The driver allocates the KLOCK_QUEUE_HANDLE structure, and passes it to KeAcquireInStackQueuedSpinLock and KeAcquireInStackQueuedSpinLockAtDpcLevel to acquire the queued spin lock. Those routines initialize the structure to represent the queued spin lock. The driver passes the structure to KeReleaseInStackQueuedSpinLock and KeReleaseInStackQueuedSpinLockFromDpcLevel when releasing the spin lock.
For more information, see Queued Spin Locks.