Merge branch 'AF_VSOCK-missed-wakeups'

Claudio Imbrenda says:

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AF_VSOCK: Shrink the area influenced by prepare_to_wait

This patchset applies on net-next.

I think I found a problem with the patch submitted by Laura Abbott
( https://lkml.org/lkml/2016/2/4/711 ): we might miss wakeups.
Since the condition is not checked between the prepare_to_wait and the
schedule(), if a wakeup happens after the condition is checked but before
the sleep happens, and we miss it. ( A description of the problem can be
found here: http://www.makelinux.net/ldd3/chp-6-sect-2 ).

The first patch reverts the previous broken patch, while the second patch
properly fixes the sleep-while-waiting issue.
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Signed-off-by: David S. Miller <davem@davemloft.net>