[dm-devel] Re: [2.6.22 PATCH 22/26] dm: bio list helpers
Andrew Morton
akpm at linux-foundation.org
Wed May 9 00:41:59 UTC 2007
On Tue, 8 May 2007 20:48:45 +0100
Alasdair G Kergon <agk at redhat.com> wrote:
> +#define BIO_LIST_INIT { .head = NULL, .tail = NULL }
> +
> +#define BIO_LIST(bl) \
> + struct bio_list bl = BIO_LIST_INIT
BIO_LIST is a strange name for something which initialises storage.
> static inline void bio_list_init(struct bio_list *bl)
> {
> bl->head = bl->tail = NULL;
> }
>
> +#define bio_list_for_each(bio, bl) \
> + for (bio = (bl)->head; bio && ({ prefetch(bio->bi_next); 1; }); \
> + bio = bio->bi_next)
> +
I have this vague memory from a long time ago that one particular CPU type
wants to go oops when prefetching from an invalid address.
Maybe that went away for some reason - we'd have hit it again if it was
real.
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