WdfMemoryCreateFromLookaside - NtDoc
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headers
// wdfmemory.h
NTSTATUS WdfMemoryCreateFromLookaside(
[in] WDFLOOKASIDE Lookaside,
[out] WDFMEMORY *Memory
);
View the official Windows Driver Kit DDI referenceNo description available.
[Applies to KMDF only]
The WdfMemoryCreateFromLookaside method creates a framework memory object and obtains a memory buffer from a specified lookaside list.
Lookaside [in]A handle to a framework lookaside-list object that is obtained by calling WdfLookasideListCreate.
Memory [out]A pointer to a location that receives a handle to the new framework memory object.
WdfMemoryCreateFromLookaside returns STATUS_SUCCESS if the operation succeeds. Otherwise, this method return one of the following values:
| Return code | Description |
|---|---|
| STATUS_INVALID_PARAMETER | An invalid parameter was detected. |
| STATUS_INSUFFICIENT_RESOURCES | There was insufficient memory. |
This method also might return other NTSTATUS values.
A bug check occurs if the driver supplies an invalid object handle.
After your driver calls WdfLookasideListCreate to create a lookaside-list object, the driver can call WdfMemoryCreateFromLookaside to obtain a buffer from the lookaside list.
The framework provides a handle to a memory object that represents the buffer. When the framework creates the memory object, it uses object attributes that the driver supplied when it called WdfMemoryCreateFromLookaside.
When your driver has finished using a memory object that it obtained from a lookaside list, the driver must call WdfObjectDelete to return the memory object to the lookaside list.
For more information about framework memory objects and lookaside lists, see Using Memory Buffers.
If lookaside-list buffers are being allocated from the pageable memory pool, the WdfMemoryCreateFromLookaside method must be called at IRQL <= APC_LEVEL. Otherwise, the method can be called at IRQL <= DISPATCH_LEVEL.
The following code example creates a lookaside list and stores the list's handle in driver-defined device object context space. Then, the driver obtains a buffer from the lookaside list.
PDRIVER_CONTEXT driverContext;
WDFMEMORY memHandle;
driverContext = GetDriverContext(driver);
status = WdfLookasideListCreate(
WDF_NO_OBJECT_ATTRIBUTES,
sizeof(MY_LOOKASIDE_BUFFER),
NonPagedPool,
WDF_NO_OBJECT_ATTRIBUTES,
MY_POOL_TAG,
&driverContext->LookasideListHandle
);
...
status = WdfMemoryCreateFromLookaside(
driverContext->LookasideListHandle,
&memHandle
);