NdisMFreeSharedMemory

NdisMFreeSharedMemory frees memory that was previously allocated by NdisMAllocateSharedMemory or NdisMAllocateSharedMemoryAsync by the driver of a DMA NIC.

VOID 
  NdisMFreeSharedMemory(
    IN NDIS_HANDLE  MiniportAdapterHandle,
    IN ULONG  Length,
    IN BOOLEAN  Cached,
    IN PVOID  VirtualAddress,
    IN NDIS_PHYSICAL_ADDRESS  PhysicalAddress
    );

Parameters

MiniportAdapterHandle

Specifies the handle originally input to MiniportInitialize.

Length

Specifies the number of bytes originally allocated.

Cached

Specifies TRUE if the original allocation was cacheable.

VirtualAddress

Specifies the base virtual address returned by NdisMAllocateSharedMemory or NdisMAllocateSharedMemoryAsync.

PhysicalAddress

Specifies the corresponding physical address returned by NdisMAllocateSharedMemory or NdisMAllocateSharedMemoryAsync.

Headers

Declared in Ndis.h. Include Ndis.h.

Comments

If it has already made a successful call to NdisMAllocateSharedMemory or NdisMAllocateSharedMemoryAsync, the NIC driver of a DMA device calls NdisMFreeSharedMemory if any of the following occurs:

• Its MiniportInitialize function is unable to initialize the NIC, so this function must release all existing claims on hardware resources for that NIC before it returns control.
• The NIC for which the miniport driver allocated the memory is being removed.
• The driver is being unloaded, whether because the system is shutting down or because the user reconfigured the network components used in the machine.
• The driver allocated additional shared memory with NdisMAllocateSharedMemoryAsync when I/O demand on its NIC was high but network traffic has now subsided to an average level.

A miniport driver cannot call NdisMFreeSharedMemory to free a subrange within an allocated shared memory range. The parameters passed to NdisMFreeSharedMemory must match exactly those that were passed to NdisMAllocateSharedMemory or NdisMAllocateSharedMemoryAsync.

NdisMFreeSharedMemory cannot be called from a MiniportShutdown function.

Before calling NdisMFreeMapRegisters, a miniport driver must free any shared memory that it has allocated.

Windows Server 2003 and Windows XP Service Pack 1 and later releases allow both bus-master DMA NICs and slave DMA NICs to call NdisMFreeSharedMemory. Prior releases allow only bus-master DMA NICs to call NdisMFreeSharedMemory.

Callers of NdisMFreeSharedMemory run at IRQL = DISPATCH_LEVEL, except when in the context of MiniportHalt or MiniportInitialize (a failed initialization code path), in which case callers of this function must run at IRQL = PASSIVE_LEVEL.

See Also

MiniportAllocateComplete, MiniportHalt, MiniportInitialize, MiniportShutdown, NdisMAllocateSharedMemory, NdisMAllocateSharedMemoryAsync, NdisMFreeMapRegisters