PFREE_COMMON_BUFFER callback function (wdm.h)
The FreeCommonBuffer routine frees a common buffer allocated by AllocateCommonBuffer, along with all resources the buffer uses.
Syntax
PFREE_COMMON_BUFFER PfreeCommonBuffer;
void PfreeCommonBuffer(
[in] PDMA_ADAPTER DmaAdapter,
[in] ULONG Length,
[in] PHYSICAL_ADDRESS LogicalAddress,
[in] PVOID VirtualAddress,
[in] BOOLEAN CacheEnabled
)
{...}
Parameters
[in] DmaAdapter
Pointer to the DMA_ADAPTER structure returned by IoGetDmaAdapter that represents the bus-master adapter or DMA controller.
[in] Length
Specifies the number of bytes to deallocate.
[in] LogicalAddress
Specifies the logical address of the allocated memory range.
[in] VirtualAddress
Pointer to the corresponding virtual address of the allocated memory range.
[in] CacheEnabled
Indicates whether the allocated memory is cached.
Return value
None
Remarks
FreeCommonBuffer is not a system routine that can be called directly by name. This routine is callable only by pointer from the address returned in a DMA_OPERATIONS structure. Drivers obtain the address of this routine by calling IoGetDmaAdapter.
To release a common buffer, a driver calls FreeCommonBuffer to unmap both its logical and virtual addresses. The parameters passed to FreeCommonBuffer must match exactly those passed to and returned from AllocateCommonBuffer. A driver cannot free part of an allocated common buffer.
Requirements
| Requirement | Value |
|---|---|
| Minimum supported client | Available starting with Windows 2000. |
| Target Platform | Desktop |
| Header | wdm.h (include Wdm.h, Ntddk.h, Ntifs.h) |
| IRQL | PASSIVE_LEVEL |
| DDI compliance rules | IrqlDispatch(wdm) |