[PATCH] drm/prime: remove cargo-cult locking from map_sg helper

[Konrad Rzeszutek Wilk]

> So after a bit of irc chatting with Maarten this seems to be more
> involved. The above check is to cache the dma mapping, but the
> implementation is bogus in tons of ways:
> - If direction changes we don't bother with unmaping and freeing the
> mapping, but simply leak it.
> - This will break if the dma mapping needs explicit syncing since the
> helpers don't call sync_to_cpu/sync_to_device anywhere.

Right, and I believe I signed up for that.
> 
> So I think I'll decline to poke around more in this hornet nest and
> leave it at the locking removal.

.. and I get the hornet nest :-). Is there a IRC log of what you guys talked
about so I don't omit certain pieces of code.