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    SubjectRe: [dm-devel] [PATCH v5 12/12] block: Only clone bio vecs that are in use
    On Wed, Aug 8, 2012 at 8:19 PM, Kent Overstreet <> wrote:
    > In particular, if this change breaks anything then the new bio_split()
    > _will_ break things.
    > We need to be clear about our interfaces; in this case bi_idx and
    > bi_vcnt, in particular. Either this is a safe change, or it's not. If
    > no one knows... that's a bigger problem, and not just for this patch...
    > Fortunately this code actually has been tested quite a bit (and the bio
    > splitting code for even longer), and (somewhat to my surprise) I haven't
    > run into any bugs caused by it.

    Oh, it's worse than that - remember how bio_kmalloc() works for up to
    1024 pages, but bio_alloc_bioset() only up to 256?

    We can already have situations where bios are allocated that are
    impossible to clone (or if we don't, it's only because of
    queue_limits. That's not sketchy at all.)

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      Last update: 2012-08-09 06:01    [W:0.022 / U:17.044 seconds]
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