Copy stable/9 to releng/9.3 as part of the 9.3-RELEASE cycle.

Approved by: re (implicit)
Sponsored by: The FreeBSD Foundation

Copy head to stable/9 as part of 9.0-RELEASE release cycle.

Approved by: re (implicit)

Style nits.

(S)LIST_HEAD_INITIALIZER takes a (S)LIST_HEAD as an argument.
Fix some wrong usages.
Note: this does not affect generated binaries as this argument is not used.

PR: 137213
Submitted by: Eygene Ryabinkin (initial version)
MFC after: 1 month

The signature for a pthread function requires that it
return a pointer to a void. The send_thread() and disk_thread()
funtions; however, do not have a return value because they run for
the duration of the daemon's lifetime. This causes gcc to barf when
running with -O3. Make these functions return a null pointer to quiet it.

PR: bin/124342
Submitted by: Garrett Cooper <gcooper@FreeBSD.org> (minus his comments)
MFC after: 1 week

Fix spelling

PR: kern/124723
Event: Bugathon#5

For consistency use 'unsigned' instead of 'u_int'.

Fix ggated for platforms with 64bit size_t. The DIOCGSECTORSIZE ioctl
returns u_int.

Reported by: Javier Martín Rueda <jmrueda@diatel.upm.es>
PR: amd64/91799
MFC after: 3 days

Reimplement ggatec/ggated applications.

Change communication protocol to be much more resistant on network
problems and to allow for much better performance.

Better performance is achieved by creating two connections between
ggatec and ggated one for sending the data and one for receiving it.
Every connection is handled by separeted thread, so there is no more
synchronous data flow (send and wait for response), now one threads
sends all requests and another receives the data.

Use two threads in ggatec(8):
- sendtd, which takes I/O requests from the kernel and sends them to the
ggated daemon on the other end;
- recvtd, which waits for ggated responses and forwards them to the kernel.

Use three threads in ggated(8):
- recvtd, which waits for I/O requests and puts them onto incoming queue;
- disktd, which takes requests from the incoming queue, does disk operations
and puts finished requests onto outgoing queue;
- sendtd, which takes finished requests from the outgoing queue and sends
responses back to ggatec.

Because there were major changes in communication protocol, there is no
backward compatibility, from now on, both client and server has to run
on 5.x or 6.x (or at least ggated should be from the same FreeBSD version
on which ggatec is running).

For Gbit networks some buffers need to be increased. I use those settings:
kern.ipc.maxsockbuf=16777216
net.inet.tcp.sendspace=8388608
net.inet.tcp.recvspace=8388608
and I use '-S 4194304 -R 4194304' options for both, ggatec and ggated.

Approved by: re (scottl)

Sort sections.

Added the EXIT STATUS section where appropriate.

Fix/clean up return values checking.

Remove extra semicolon.

Inspired by: fjoe

Various style.Makefile(5) improvements.

Provoked by: ru

Polish the mdoc(7) markup.

Include <sys/time.h> for the declaration of struct bintime instead of
depending on namespace pollution in <sys/stat.h>. struct bintime is
only needed to satisfy leakage of kernel interfaces to userland and
namespace bugs in those interfaces...

Paths correction.

Pointed out by: ache, make buildworld

Fix compiling on 64-bit architectures.

GEOM Gate network daemon.