2.3.2.6 Synchronization Functions

The following table defines the synchronization functions included in the NDIS library for miniport drivers.

The timer functions allow the miniport to implement an operation that occurs at a driver-requested interval. For instance, a driver can use a timer to poll its NIC. Events can be used to synchronize operations between two threads, at least one running at IRQL PASSIVE_LEVEL. Spin locks are used to synchronize access to shared resources, as is the NdisMSynchronizeWithInterrupt function.

Function

Definition

NdisMCancelTimer

Cancels a timer that was previously set with NdisMSetTimer.

NdisMInitializeTimer

Initializes a timer object and associates a MiniportTimer function with the object.

NdisMSetTimer

Sets a timer to go off after a specified interval.

NdisMSetPeriodicTimer

Sets a timer that goes off automatically at a specified interval of until cancelled with a call to NdisMCancelTimer.

NdisSleep

Causes the caller’s thread to block for the specified interval. A driver calls NdisSleep during initialization or when halting the adapter, for instance, while waiting for the NIC to complete initialization. NdisSleep is only called at IRQL PASSIVE_LEVEL.

NdisStallExecution

Causes the caller’s thread to stall for a specified interval not to exceed 50 milliseconds. NdisStallExecution is only called at raised IRQL when NdisSleep cannot be used.

NdisInitializeEvent

Creates and initializes an event which can then be used to synchronize driver operations.

NdisSetEvent

Signals the specified event.

NdisResetEvent

Resets the specified event to the unsignaled state.

NdisWaitEvent

Causes the caller to wait until the specified event is signaled or the specified time interval expires.

NdisAcquireSpinLock

Acquires a spin lock to protect access to shared resources between nonISR driver functions in an SMP-safe way. Miniports that are running at IRQL < DISPATCH_LEVEL call this function to acquire a spin lock.

NdisReleaseSpinLock

Releases a spin lock previously acquired by calling NdisAcquireSpinLock.

NdisDprAcquireSpinLock

Acquires a spin lock at IRQL DISPATCH_LEVEL. Protects access to shared resources between nonISR driver functions in an SMP-safe way. Faster than calling NdisAcquireSpinLock for driver functions running at IRQL DISPATCH_LEVEL.

NdisDprReleaseSpinLock

Releases a spin lock previously acquired by calling NdisDprAcquireSpinLock.

NdisMSynchronizeWithInterrupt

Any NIC driver function that shares resources with the MiniportISR or MiniportDisableInterrupt functions must synchronize access to the resources with these two functions to prevent race conditions. Such functions that must synchronize with MiniportISR and MiniportDisableInterrupt do so by calling NdisMSynchronizeWithInterrupt with a MiniportSynchronizeISR function that also runs at DIRQL while it accesses the shared resource.

Function	Definition
NdisMCancelTimer	Cancels a timer that was previously set with NdisMSetTimer.
NdisMInitializeTimer	Initializes a timer object and associates a MiniportTimer function with the object.
NdisMSetTimer	Sets a timer to go off after a specified interval.
NdisMSetPeriodicTimer	Sets a timer that goes off automatically at a specified interval of until cancelled with a call to NdisMCancelTimer.
NdisSleep	Causes the caller’s thread to block for the specified interval. A driver calls NdisSleep during initialization or when halting the adapter, for instance, while waiting for the NIC to complete initialization. NdisSleep is only called at IRQL PASSIVE_LEVEL.
NdisStallExecution	Causes the caller’s thread to stall for a specified interval not to exceed 50 milliseconds. NdisStallExecution is only called at raised IRQL when NdisSleep cannot be used.
NdisInitializeEvent	Creates and initializes an event which can then be used to synchronize driver operations.
NdisSetEvent	Signals the specified event.
NdisResetEvent	Resets the specified event to the unsignaled state.
NdisWaitEvent	Causes the caller to wait until the specified event is signaled or the specified time interval expires.
NdisAcquireSpinLock	Acquires a spin lock to protect access to shared resources between nonISR driver functions in an SMP-safe way. Miniports that are running at IRQL < DISPATCH_LEVEL call this function to acquire a spin lock.
NdisReleaseSpinLock	Releases a spin lock previously acquired by calling NdisAcquireSpinLock.
NdisDprAcquireSpinLock	Acquires a spin lock at IRQL DISPATCH_LEVEL. Protects access to shared resources between nonISR driver functions in an SMP-safe way. Faster than calling NdisAcquireSpinLock for driver functions running at IRQL DISPATCH_LEVEL.
NdisDprReleaseSpinLock	Releases a spin lock previously acquired by calling NdisDprAcquireSpinLock.
NdisMSynchronizeWithInterrupt	Any NIC driver function that shares resources with the MiniportISR or MiniportDisableInterrupt functions must synchronize access to the resources with these two functions to prevent race conditions. Such functions that must synchronize with MiniportISR and MiniportDisableInterrupt do so by calling NdisMSynchronizeWithInterrupt with a MiniportSynchronizeISR function that also runs at DIRQL while it accesses the shared resource.