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    SubjectRe: 2.6.27-rc4: lots of 'in_atomic():1, irqs_disabled():0' with software-raid1
    On Thursday August 28, wrote:
    > On Thu, Aug 28 2008, Andrew Morton wrote:
    > >
    > > Cant sleep inside rcu_read_lock(), with CONFIG_PREEMPT_RCU=n, at least.
    > >
    > > Dunno if it's legal if CONFIG_PREEMPT_RCU=y. Hopefully not - that
    > > would be insane. But I've failed to keep up with rcu goings-on
    > > recently.
    > Doh right, we of course can't block inside a RCU section. Then
    > bitmap.c:write_sb_page() wants fixing:
    > rcu_read_lock();
    > rdev_for_each_rcu(...)
    > md_super_write(...)
    > bio_alloc(GFP_NOIO, 1);
    > Neil?


    And not only can't I call bio_alloc inside the rcu_read_lock, I also
    cannot call submit_bio, as that can do a mempool alloc for a request
    I can get around that by putting the bios on the ->biolist that
    md_super_wait will resubmit requests from. But I still need to
    allocate those bios.
    Maybe I can count how many there need to be, then allocate them and
    make a list, then pass them down into md_super_write.
    It's a bit ugly but it should work.

    I think I'll have to think about it a bit more.


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      Last update: 2008-08-28 10:29    [W:0.020 / U:16.992 seconds]
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