Re: [RFC PATCH 2/7] lib: Add huge I/O map capability interfaces

From: Toshi Kani
Date: Tue Jan 27 2015 - 17:17:47 EST


On Tue, 2015-01-27 at 13:37 -0800, Andrew Morton wrote:
> On Mon, 26 Jan 2015 18:01:55 -0700 Toshi Kani <toshi.kani@xxxxxx> wrote:
>
> > > > static int ioremap_pte_range(pmd_t *pmd, unsigned long addr,
> > > > unsigned long end, phys_addr_t phys_addr, pgprot_t prot)
> > > > {
> > > > @@ -74,6 +112,12 @@ int ioremap_page_range(unsigned long addr,
> > > > unsigned long start;
> > > > unsigned long next;
> > > > int err;
> > > > + static int ioremap_huge_init_done;
> > > > +
> > > > + if (!ioremap_huge_init_done) {
> > > > + ioremap_huge_init_done = 1;
> > > > + ioremap_huge_init();
> > > > + }
> > >
> > > Looks hacky. Why can't we just get the startup ordering correct? It
> > > at least needs a comment which fully explains the situation.
> >
> > How about calling it from mm_init() after vmalloc_init()?
> >
> > void __init mm_init(void)
> > :
> > percpu_init_late();
> > pgtable_init();
> > vmalloc_init();
> > + ioremap_huge_init();
> > }
>
> Sure, that would be better, assuming it can be made to work.

Yes, I verified that ioremap() works right after this point.

> Don't forget to mark ioremap_huge_init() as __init.

Right.

Thanks,
-Toshi


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