MFstable/11 r303691:

MFC r302550,r302551,r302552,r302553:

r302550:

Deobfuscate cleanup path in clnt_dg_create(..)

Similar to r300836 and r301800, cl and cu will always be non-NULL as they're
allocated using the mem_alloc routines, which always use
`malloc(..., M_WAITOK)`.

Deobfuscating the cleanup path fixes a leak where if cl was NULL and
cu was not, cu would not be free'd, and also removes a duplicate test for
cl not being NULL.

CID: 1007033, 1007344

r302551:

Deobfuscate cleanup path in clnt_vc_create(..)

Similar to r300836, r301800, and r302550, cl and ct will always
be non-NULL as they're allocated using the mem_alloc routines,
which always use `malloc(..., M_WAITOK)`.

CID: 1007342

r302552:

Convert `svc_xprt_alloc(..)` and `svc_xprt_free(..)`'s prototypes to
ANSI C style prototypes

r302553:

Don't test for xpt not being NULL before calling svc_xprt_free(..)

svc_xprt_alloc(..) will always return initialized memory as it uses
mem_alloc(..) under the covers, which uses malloc(.., M_WAITOK, ..).

CID: 1007341

MFC r260229, r260258, r260367, r260390, r260459, r260648:
Rework NFS Duplicate Request Cache cleanup logic.

- Introduce additional hash to group requests by hash of sockref. This
allows to process TCP acknowledgements without looping though all the cache,
and as result allows to do it every time.
- Indroduce additional callbacks to notify application layer about sockets
disconnection. Without this last few requests processed just before socket
disconnection never processed their ACKs and stuck in cache for many hours.
- Implement transport-specific method for tracking reply acknowledgements.
New implementation does not cross multiple stack layers to get the data and
does not have race conditions that previously made some requests stuck
in cache. This could be done more efficiently at sockbuf layer, but that
would broke some KBIs, while I don't know other consumers for it aside NFS.
- Instead of traversing all DRC twice per request, run cleaning only once
per request, and except in some conditions traverse only single hash slot
at a time.

Together this limits NFS DRC growth only to situations of real connectivity
problems. If network is working well, and so all replies are acknowledged,
cache remains almost empty even after hours of heavy load. Without this
change on the same test cache was growing to many thousand requests even
with perfectly working local network.

As another result this reduces CPU time spent on the DRC handling during
SPEC NFS benchmark from about 10% to 0.5%.

Sponsored by: iXsystems, Inc.

MFC r260036:
Introduce xprt_inactive_self() -- variant for use when sure that port
is assigned to thread. For example, withing receive handlers. In that
case the function reduces to single assignment and can avoid locking.

MFC r258578, r258580, r258581 (by hrs):
Replace Sun RPC license in TI-RPC library with a 3-clause BSD license
with the explicit permissions.

MFC r260229, r260258, r260367, r260390, r260459, r260648:
Rework NFS Duplicate Request Cache cleanup logic.

- Introduce additional hash to group requests by hash of sockref. This
allows to process TCP acknowledgements without looping though all the cache,
and as result allows to do it every time.
- Indroduce additional callbacks to notify application layer about sockets
disconnection. Without this last few requests processed just before socket
disconnection never processed their ACKs and stuck in cache for many hours.
- Implement transport-specific method for tracking reply acknowledgements.
New implementation does not cross multiple stack layers to get the data and
does not have race conditions that previously made some requests stuck
in cache. This could be done more efficiently at sockbuf layer, but that
would broke some KBIs, while I don't know other consumers for it aside NFS.
- Instead of traversing all DRC twice per request, run cleaning only once
per request, and except in some conditions traverse only single hash slot
at a time.

Together this limits NFS DRC growth only to situations of real connectivity
problems. If network is working well, and so all replies are acknowledged,
cache remains almost empty even after hours of heavy load. Without this
change on the same test cache was growing to many thousand requests even
with perfectly working local network.

As another result this reduces CPU time spent on the DRC handling during
SPEC NFS benchmark from about 10% to 0.5%.

Sponsored by: iXsystems, Inc.

MFC r260036:
Introduce xprt_inactive_self() -- variant for use when sure that port
is assigned to thread. For example, withing receive handlers. In that
case the function reduces to single assignment and can avoid locking.

MFC r258578, r258580, r258581 (by hrs):
Replace Sun RPC license in TI-RPC library with a 3-clause BSD license
with the explicit permissions.