tx path circular buffer

Hi,

I am attempting to implement a circular buffer for the tx path of a
networking driver. From my understanding this is something that is
very common, yet I am struggling to find a clear way to do it.

I have tried to read the source for ath6kl, brcmfmac without
success.

I have read Documentation/circular-buffers.txt and this seems like the
solution however grep'ing drivers/net hints that this is not that
common a way to solve this problem. Also I'm getting in knots with
atomic_t types when copying the text document.

Before I bore you with all my non-working code, does any one please
know, off the top of their heads, a driver with simple-ish / nice clean
implementation that I can learn from?

thanks,
Tobin.