From: Niklas Cassel <[email protected]>
Date: Wed, 7 Mar 2018 18:21:57 +0100
> Considering this, you can drop/revert:
> 95eb930a40a0 ("net: stmmac: use correct barrier between coherent memory and
> MMIO")
> or perhaps you want me to send a revert?
You must submit explicit patches to do a revert or any other change.
> After reverting 95eb930a40a0, we will still have a dma_wmb() _after_ the
> last descriptor word write. You just explained that nothing else is needed
> after the last descriptor word write, so I actually think that this last
> barrier is superfluous.
You don't need one after the last descriptor write.
Look, you're only concerned with ordering within the descriptor writes.
So it's only about:
desc->a = x;
/* Write to 'a' must be visible to the hardware before 'b'. */
dma_wmb();
desc->b = y;
writel();
That's all that you need.
