Merge branch 'net-tls-add-a-TX-lock'

Jakub Kicinski says:

====================
net/tls: add a TX lock

Some time ago Pooja and Mallesham started reporting crashes with
an async accelerator. After trying to poke the existing logic into
shape I came to the conclusion that it can't be trusted, and to
preserve our sanity we should just add a lock around the TX side.

First patch removes the sk_write_pending checks from the write
space callbacks. Those don't seem to have a logical justification.

Patch 2 adds the TX lock and patch 3 associated test (which should
hang with current net).

Mallesham reports that even with these fixes applied the async
accelerator workload still occasionally hangs waiting for socket
memory. I suspect that's strictly related to the way async crypto
is integrated in TLS, so I think we should get these into net or
net-next and move from there.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>