Re: [patch] cache pipe buf page address for non-highmem arch

[Andrew Morton <akpm@linux-foundation.org>]

On Tue, 27 Mar 2007 15:57:53 -0700
Zach Brown <zach.brown@oracle.com> wrote:

> > +#define pipe_kmap_atomic(page, type)	pipe_kmap(page)
> > +#define pipe_kunmap(page)		do { } while (0)
> > +#define pipe_kunmap_atomic(page, type)	do { } while (0)
> 
> Please don't drop arguments in stubs.  It can let completely broken  
> code compile, like:
> 
> 	pipe_kunmap(SOME_COMPLETE_NONSENSE);
> 
> Static inlines with empty bodies are the gold standard.
> 

yup.

<fiddle, fiddle>

Does this look OK?

#ifdef CONFIG_HIGHMEM
static inline void *pipe_kmap(struct page *page)
{
	return kmap(page);
}

static inline void pipe_kunmap(struct page *page)
{
	kunmap(page);
}

static inline void *pipe_kmap_atomic(struct page *page, enum km_type type)
{
	return kmap_atomic(page, type);
}

static inline void pipe_kunmap_atomic(void *addr, enum km_type type)
{
	kunmap_atomic(addr, type);
}
#else	/* CONFIG_HIGHMEM */
static inline void *pipe_kmap(struct page *page)
{
	return (void *)page->private;
}

static inline void pipe_kunmap(struct page *page)
{
}

static inline void *pipe_kmap_atomic(struct page *page, enum km_type type)
{
	return (void *)page->private;
}

static inline void pipe_kunmap_atomic(struct page *page, enum km_type type)
{
}
#endif