On Tue, 6 Feb 2007 09:02:11 +0100 (CET) Nick Piggin <npiggin@xxxxxxx> wrote:
> +static inline void __SetPageUptodate(struct page *page)
> +{
> +#ifdef CONFIG_S390
> if (!test_and_set_bit(PG_uptodate, &page->flags))
> page_test_and_clear_dirty(page);
> -}
> #else
> -#define SetPageUptodate(page) set_bit(PG_uptodate, &(page)->flags)
> + /*
> + * Memory barrier must be issued before setting the PG_uptodate bit,
> + * so all previous writes that served to bring the page uptodate are
> + * visible before PageUptodate becomes true.
> + *
> + * S390 is guaranteed to have a barrier in the test_and_set operation
> + * (see Documentation/atomic_ops.txt).
> + *
> + * XXX: does this memory barrier need to be anything special to
> + * handle things like DMA writes into the page?
> + */
> + smp_wmb();
> + set_bit(PG_uptodate, &(page)->flags);
> #endif
> +}
> +
> +static inline void SetPageUptodate(struct page *page)
> +{
> + WARN_ON(!PageLocked(page));
> + __SetPageUptodate(page);
> +}
> +
> +static inline void SetNewPageUptodate(struct page *page)
> +{
> + __SetPageUptodate(page);
> +}
I was panicing for a minute when I saw that __SetPageUptodate() in there.
Conventionally the __SetPageFoo namespace is for nonatomic updates to
page->flags. Can we call this something different?
What a fugly patchset :(
-
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