NdisAcquireSpinLock macro (ndis.h)
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] _SpinLock
);
Parameters
[in] _SpinLock
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
| Requirement | Value |
|---|---|
| Minimum supported client | 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. |
| Target Platform | Universal |
| Header | ndis.h (include Ndis.h) |
| Library | Ndis.lib |
| IRQL | <= DISPATCH_LEVEL |
| DDI compliance rules | Irql_Synch_Function(ndis), SpinLock(ndis), SpinLockBalanced(ndis), SpinLockDpr(ndis), SpinLockDprRelease(ndis), SpinlockRelease(ndis) |