RxInitializeContext function (rxcontx.h)

Artikel
02/22/2024

RxInitializeContext initializes an existing RX_CONTEXT data structure.

Syntax

void RxInitializeContext(
  [in, optional] IN PIRP                 Irp,
  [in]           IN PRDBSS_DEVICE_OBJECT RxDeviceObject,
  [in]           IN ULONG                InitialContextFlags,
  [in, out]      IN OUT PRX_CONTEXT      RxContext
);

Parameters

[in, optional] Irp

A pointer to the IRP to be encapsulated by this RX_CONTEXT structure.

[in] RxDeviceObject

A pointer to the device object to which this RX_CONTEXT and IRP apply.

[in] InitialContextFlags

The set of initial values for Flags member of the RX_CONTEXT data structure to be stored in the RX_CONTEXT structure. These initial values can be any combination of the following enumerations:

RX_CONTEXT_FLAG_WAIT

When this value is set, the IRP should be not be posted for later execution by the file system process, but should be waited on to complete.

RX_CONTEXT_FLAG_MUST_SUCCEED

When this value is set, the operation must succeed. This value is not currently used by RDBSS, but it may be used by network mini-redirector drivers.

RX_CONTEXT_FLAG_MUST_SUCCEED_NONBLOCKING

When this value is set, the operation must succeed for non-blocking operations. This value is not currently used by RDBSS, but it may be used by network mini-redirector drivers.

[in, out] RxContext

Pointer to the RX_CONTEXT to be initialized.

Return value

None

Remarks

RxInitializeContext is called internally by the RxCreateRxContext routine. So the RxInitializeContext routine would normally only be used by network min-redirector drivers that allocate RX_CONTEXT structures directly rather than calling the RxCreateRxContext routine to allocate and initialize an RX_CONTEXT structure.

If the Irp parameter is configured for asynchronous operation, then the Flags member of the RX_CONTEXT structure pointed to by RxContext also has the following value set:

RX_CONTEXT_FLAG_ASYNC_OPERATION is also set for the following conditions:

The MajorFunction member of the Irp is IRP_MJ_READ, IRP_MJ_WRITE, or IRP_MJ_DEVICE_CONTROL.
The MajorFunction member of the Irp is an IRP_MJ_DIRECTORY_CONTROL and the MinorFunction member of the IRP is an IRP_MN_NOTIFY_CHANGE_DIRECTORY.
The MajorFunction member of the Irp is an IRP_MJ_FILE_SYSTEM_CONTROL and NetRoot member of the associated FCB is not NULL and the Type member of the NET_ROOT is NET_ROOT_PIPE.

If this is a recursive file system call (the TopLevelIrp member in the thread local storage is the current Irp) then the Flags member of RxContext also has the following value set:

If the RxDeviceObject parameter indicates that this is the top level RDBSS device object, then the Flags member of the RX_CONTEXT structure also has the following value set:

If the Irp FileObject Flags member has the FO_WRITE_THROUGH option set, then the Flags member of the RX_CONTEXT structure also has the following value set:

RxInitializeContext sets a number of other members in the RX_CONTEXT structure including the following:

Sets the proper NodeTypeCode, NodeByteSize, SerialNumber, RxDeviceObject, and initializes the ReferenceCount to 1.
Initializes the SyncEvent
Initialize the associated ScavengerEntry
Initializes the list entry of BlockedOperations
Sets the RX_CONTEXT members based on the Irp. These include CurrentIrp, OriginalThread, MajorFunction, MinorFunction, CurrentIrpSp, pFcb, NonPagedFcb, pFobx, pRelevantSrvOpen, and FobxSerialNumber members.

Requirements

Requirement	Value
Target Platform	Desktop
Header	rxcontx.h (include Rxprocs.h rxcontx.h)
IRQL	<= APC_LEVEL

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