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    SubjectRe: [PATCH 1/4] async: introduce 'async_domain' type
    On Fri, 2012-05-25 at 01:18 -0700, Dan Williams wrote:
    > On Fri, May 25, 2012 at 12:51 AM, James Bottomley
    > <> wrote:
    > > On Fri, 2012-05-25 at 00:50 -0700, Dan Williams wrote:
    > >> This is in preparation for teaching async_synchronize_full() to sync all
    > >> pending async work, and not just on the async_running domain. This
    > >> conversion is functionally equivalent, just embedding the existing list
    > >> in a new async_domain type.
    > >
    > > This looks good, but I want Arjan and others who invented the async code
    > > to speed up boot to comment on all of this. What was the intention of
    > > async_synchronize_full() and if it wasn't to synchronise all domains,
    > > should we fix the documentation and add a new primitive to do that,
    > > since boot clearly assumes the all domains behaviour.
    > >
    > > In the mean time, this is probably all a bit much for a merge window, so
    > > I'll revert
    > >
    > > commit a7a20d103994fd760766e6c9d494daa569cbfe06
    > > Author: Dan Williams <>
    > > Date: Thu Mar 22 17:05:11 2012 -0700
    > >
    > > [SCSI] sd: limit the scope of the async probe domain
    > >
    > > And we'll put whatever is chosen in early for the next merge window.
    > >
    > Makes sense... but could also go ahead with the smaller fix I posted
    > for 3.5. Meelis confirms it is working.

    OK, that's what I hadn't seen. I can't think of another way we could
    fail at the moment, except in suspend/resume because the
    scsi_complete_async_scans will be a nop. Can someone test the
    suspend/resume case?

    There is actually one good thing to come out of this: Rafael's commit

    commit c751085943362143f84346d274e0011419c84202
    Author: Rafael J. Wysocki <>
    Date: Sun Apr 12 20:06:56 2009 +0200

    PM/Hibernate: Wait for SCSI devices scan to complete during resume

    Actually broke the scsi_wait_scan module, because for modular SCSI
    (which is effectively all distributions) its scsi_complete_async_scans()
    is also a nop. I assume this means that no distributions rely on it any
    more and we can remove it?

    > Otherwise this leaves the pending libsas suspend/resume support in
    > limbo, since it will certainly deadlock in the case where any device
    > fails, or is slow to come back from resume.

    I appreciate this is a bug, but it's not quite as serious as breaking
    suspend and hibernate ... can we demonstrate they're still working?


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