Re: [PATCH 2/6] ide: move SFF I/O code to ide-io-sff.c

Bartlomiej Zolnierkiewicz
2009-01-19T19:13:14Z

On Monday 19 January 2009, Alan Cox wrote:
> > Tried looking at how in*()/out*() are defined on x86?
>
> Tried looking at how ide_mm_inb is defined on x86
>
> > > It's already making function calls, without the benefit of inlining and
> >
> > I'm afraid you're wrong here.
>
> I'm afraid you are the one who is wrong. The IDE layer is duplicating a
> generic level of indirection with its own code - purely because IDE
> pre-dates that core functionality. The whole IDE layer indirection can go
> away because Linux has caught up with the needs of the IDE layer.

I wish it would be so simple as I would have removed the said indirection
long time ago. Unfortunately:

- not all archs support ioread() & co.

- there is still issue with cache aliasing on some CPUs

Once above deficiences get fixed we can look into ioread() conversion again.

[ IOW right now it is the correct thing to stick to ide_mm_*() indirection
since extra hardware coverage is more valuable than minor code cleanup. ]

Thanks,
Bart