Re: [PATCH v4 1/4] drm/i915: Fix up seqno -> request merge issues

Daniel Vetter
2014-12-05T20:36:37Z

On Fri, Dec 05, 2014 at 01:49:33PM +0000, John.C.Harrison@Intel.com wrote:
> From: John Harrison <John.C.Harrison@Intel.com>
>
> The display related patches earlier in this series were edited during merge to
> improve the request unreferencing. Specifically, the need for de-referencing at
> interrupt time was removed. However, the resulting code did a 'deref(req) ; req
> = NULL' sequence rather than using the 'req_assign(req, NULL)' wrapper. The two
> are functionally equivalent, but using the wrapper is more consistent with all
> the other places where requests are assigned.
>
> Note that the whole point of the wrapper is that using it everywhere that
> request pointers are assigned means that the reference counting is done
> automatically and can't be accidentally forgotten about. Plus it allows simpler
> future maintainance if the reference counting mechanisms ever need to change.
>
> For: VIZ-4377
> Signed-off-by: John Harrison <John.C.Harrison@Intel.com>

I guess it's fairly clear that i915 hasn't used this patter previously ;-)

Thanks for fixing this up. Aside, if you have a slow day: Coccinelle might
be able to automatically hunt for refactorings like this for you. And even
if not playing with that tool is worth it all on its own.
-Daniel
--
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch