NdisAcquireSpinLock (Windows Embedded CE 6.0)

1/6/2010

This function acquires a spin lock so that the caller gains exclusive access to the resources, shared among driver functions, that the spin lock protects.

Syntax

VOID NdisAcquireSpinLock(
  PNDIS_SPIN_LOCK SpinLock
);

Parameters

• SpinLock
  [in] Pointer to an opaque spin lock, already initialized by the caller.

Return Value

None.

Remarks

In the Windows Embedded CE operating system (OS), NDIS spin locks are implemented using critical sections.

The driver must initialize a variable of type NDIS_SPIN_LOCK with the NdisAllocateSpinLock function before it calls any other NDIS SpinLock function. The driver must provide resident storage for the spin locks it uses.

After acquiring a spin lock with this function, the caller releases that lock with a call to the NdisReleaseSpinLock function. A driver must call NdisReleaseSpinLock following each call to this function. Otherwise, a deadlock occurs, hanging the driver.

A spin lock acquired with the NdisDprAcquireSpinLock function must be released with the NdisDprReleaseSpinLock function.

A driver should never hold a spin lock for an extended period — more than a few instructions. Holding a spin lock for longer than 25 microseconds degrades both system and driver performance.

A miniport driver cannot use a spin lock to protect resources that its other functions share with the MiniportISR and the MiniportDisableInterrupt functions. Instead, a miniport must call the NdisMSynchronizeWithInterrupt function so that its MiniportSynchronizeISR function does not access shared resources at the same time as its MiniportISR or MiniportDisableInterrupt function.

Requirements

See Also

Reference

NDIS Library Functions
MiniportDisableInterrupt
MiniportISR
MiniportSynchronizeISR
NdisAllocateSpinLock
NdisDprAcquireSpinLock
NdisDprReleaseSpinLock
NdisMSynchronizeWithInterrupt