Re: [RESEND2 PATCH 1/3] memremap: add MEMREMAP_WC flag

[Brian Starkey]

Hi Andrew,

Thanks for taking a look,

On Mon, Feb 08, 2016 at 12:03:17PM -0800, Andrew Morton wrote:
> On Mon,  8 Feb 2016 17:30:50 +0000 Brian Starkey <brian.starkey@xxxxxxx> wrote:
> The patch generally looks OK to me.  It generates rejects against
> linux-next because of some janitorial changes in memremap.c.

Ah yeah, so it does - sorry. I was hoping this could make it into 4.5,
but I can rebase onto linux-next if that's better. Annoyingly it only
conflicts because of a couple of quotation marks.

> > @@ -101,6 +107,11 @@ void *memremap(resource_size_t offset, size_t size, unsigned long flags)
> >  		addr = ioremap_wt(offset, size);
> >  	}
> >
> > +	if (!addr && (flags & MEMREMAP_WC)) {
> > +		flags &= ~MEMREMAP_WC;
> > +		addr = ioremap_wc(offset, size);
> > +	}
> > +
> >  	return addr;
> >  }
>
> The modifications of `flags' is unneeded (and the compiler will remove
> it).  And generally the modification of incoming args is a bit nasty
> IMO - I find it's better to treat them as const - part of the calling
> environment which can be relied upon to be unaltered as the code
> evolves.

To be honest I was just mirroring the rest of the function. I guess
the idea was filtering the different mapping types in case one of the
'mappers' can handle multiple flags or something. I'll remove it if
you like, I just thought that extending the functionality in-keeping
with the current semantics was a better evolution - let me know.

Thanks,
Brian