Merge branch 'mptcp-fixes'

Mat Martineau says:

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mptcp: Miscellaneous fixes

Here are five changes we've collected and tested in the mptcp-tree:

Patch 1 changes handling of the MPTCP-level snd_next value during the
recovery phase after a subflow link failure.

Patches 2 and 3 are some small refactoring changes to replace some
open-coded bits.

Patch 4 removes an unused field in struct mptcp_sock.

Patch 5 restarts the MPTCP retransmit timer when there is
not-yet-transmitted data to send and all previously sent data has been
acknowledged. This prevents some sending stalls.
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Signed-off-by: David S. Miller <davem@davemloft.net>