WdfDeviceInitSetRemoveLockOptions function

Description

[Applies to KMDF only]

The WdfDeviceInitSetRemoveLockOptions method causes the framework to acquire a remove lock before delivering an IRP of any type to the driver.

Parameters

DeviceInit [in]

A caller-supplied pointer to a WDFDEVICE_INIT structure.

Options [in]

A pointer to a WDF_REMOVE_LOCK_OPTIONS structure.

Remarks

By default, the framework acquires a remove lock before it delivers IRPs of the following major types to the driver:

IRP_MJ_PNP

IRP_MJ_POWER

IRP_MJ_SYSTEM_CONTROL

When the IRP completes, the framework releases the remove lock.

Starting in KMDF 1.11, the driver can optionally call WdfDeviceInitSetRemoveLockOptions to cause the framework to acquire a remove lock before delivering all IRP types, not just those listed above.

If your driver has kernel-mode clients that send I/O unsynchronized with the PnP state of your device, you may experience crashes due to I/O IRPs arriving after the framework device object has been removed. In this case, you can call WdfDeviceInitSetRemoveLockOptions. Then, when a client sends an I/O request to your device:

• If the device has not yet been removed, the remove lock is acquired successfully and the request is delivered. If removal happens later, the framework calls IoReleaseRemoveLockAndWait which blocks until all successful lock acquisitions are released (I/O requests are completed).
• If the device has already processed IRP_MN_REMOVE_DEVICE, but there is an outstanding reference to a WDM device object preventing the device from being released, the remove lock is not acquired and the framework completes the request immediately.

Note WdfDeviceInitSetRemoveLockOptions is not supported on control objects.

Typically, a driver calls WdfDeviceInitSetRemoveLockOptions from within its EvtDriverDeviceAdd callback function, just before calling WdfDeviceCreate.

After a driver calls WdfDeviceInitSetRemoveLockOptions, the setting remains in effect for the lifetime of the framework device object.

For more information about remove locks, see Using Remove Locks.

Examples

This code example initializes a WDF_REMOVE_LOCK_OPTIONS structure and calls WdfDeviceInitSetRemoveLockOptions.

WDF_REMOVE_LOCK_OPTIONS RemoveLockOptions;

WDF_REMOVE_LOCK_OPTIONS_INIT(
                             &RemoveLockOptions,
                             WDF_REMOVE_LOCK_OPTION_ACQUIRE_FOR_IO
                             );
WdfDeviceInitSetRemoveLockOptions(
                                  DeviceInit,
                                  &RemoveLockOptions
                                  );

See also

WDF_REMOVE_LOCK_OPTIONS

WDF_REMOVE_LOCK_OPTIONS_FLAGS

WDF_REMOVE_LOCK_OPTIONS_INIT