Hi Arnd,

quoted

quoted

Note that the microread_is_busy() logic does not protect you from 
having multiple concurrent readers, because multiple threads may 
share a single file descriptor.

It's just used to ensure that only one reader can open the device.
It's called only in open callback.
The mutex actually secures concurrent read operations. 

So if having multiple readers is safe (though possibly not 
meaningful), I guess you don't really need the 
microread_is_busy() logic.

I suppose it doesn't hurt either, it just seems a bit 
pointless when it does the right thing most of the time, but 
not always.

Could you give me an example when the microread_is_busy() logic does not do what it's intended to do.
I don't really get your point here. 


Waldek