Question

I’m writing a simple USB driver for our device using UMDF over WinUsb. The driver can be used by multiple application concurrently.
I need to achieve a custom locking system that the WdfDeviceLevel\WdfObjectLevel doesn’t give me:
I want an atomic write-read function:

1. obtain a lock on the device
2. write a value
3. read a value
4. release the lock

How can I implement such a function? I could not find how to expose custom function on top of the the interface’s functions.
In addition to this particular atomic function, it would be nice if I could give each application the ability to obtain a lock that will block all other applications from accessing the device.

Answer 1

As the driver we are using can only be accessed via a dedicated dll, I added mutex locks in the dll level to imitate an atomic function.