NdisAcquireSpinLock function

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

Syntax


VOID NdisAcquireSpinLock(
  _In_ PNDIS_SPIN_LOCK SpinLock
);

Parameters

SpinLock [in]

Pointer to an opaque spin lock, already initialized by the caller.

Return value

None

Remarks

The driver must initialize a variable of type NDIS_SPIN_LOCK with NdisAllocateSpinLock before it calls any other NdisXxxSpinLock function. The driver must provide resident storage for the spin lock(s) it uses.

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

A spin lock acquired with NdisAcquireSpinLock must be released with NdisReleaseSpinLock. A spin lock acquired with NdisDprAcquireSpinLock must be released with NdisDprReleaseSpinLock.

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 MiniportInterrupt and/or MiniportDisableInterruptEx functions. Instead, a miniport driver must call NdisMSynchronizeWithInterruptEx so that its MiniportSynchronizeInterrupt function accesses such shared resources at the same DIRQL at which its MiniportInterrupt and/or MiniportDisableInterruptEx functions do.

For more information about acquiring and releasing NDIS spin locks, see Synchronization and Notification in Network Drivers.

Requirements

Target platform

Universal

Version

Supported for NDIS 6.0 and NDIS 5.1 drivers (see NdisAcquireSpinLock (NDIS 5.1)) in Windows Vista. Supported for NDIS 5.1 drivers (see NdisAcquireSpinLock (NDIS 5.1)) in Windows XP.

Header

Ndis.h (include Ndis.h)

Library

Ndis.lib

IRQL

<= DISPATCH_LEVEL

DDI compliance rules

Irql_Synch_Function, SpinLock, SpinLockBalanced, SpinLockDpr, SpinLockDprRelease, SpinlockRelease

See also

MiniportDisableInterruptEx
MiniportHaltEx
MiniportInitializeEx
MiniportInterrupt
MiniportSynchronizeInterrupt
NdisAllocateSpinLock
NdisDprAcquireSpinLock
NdisMSynchronizeWithInterruptEx
NdisReleaseSpinLock

 

 

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