backing-dev: use synchronize_rcu_expedited instead of synchronize_rcu

backing-dev: use synchronize_rcu_expedited instead of synchronize_rcu

synchronize_rcu sleeps several timer ticks. synchronize_rcu_expedited is
much faster.

With 100Hz timer frequency, when we remove 10000 block devices with
"dmsetup remove_all" command, it takes 27 minutes. With this patch,
removing 10000 block devices takes only 15 seconds.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
(cherry picked from commit ef3230880abd36553ab442363d3c9a0661f00769)
net: Compute protocol sequence numbers and fragment IDs using MD5.

Computers have become a lot faster since we compromised on the
partial MD4 hash which we use currently for performance reasons.

MD5 is a much safer choice, and is inline with both RFC1948 and
other ISS generators (OpenBSD, Solaris, etc.)

Furthermore, only having 24-bits of the sequence number be truly
unpredictable is a very serious limitation.  So the periodic
regeneration and 8-bit counter have been removed.  We compute and
use a full 32-bit sequence number.

For ipv6, DCCP was found to use a 32-bit truncated initial sequence
number (it needs 43-bits) and that is fixed here as well.

Reported-by: Dan Kaminsky <dan@doxpara.com>
Tested-by: Willy Tarreau <w@1wt.eu>
Signed-off-by: David S. Miller <davem@davemloft.net>
(cherry picked from commit 6e5714eaf77d79ae1c8b47e3e040ff5411b717ec)

Conflicts:

	drivers/char/random.c
	net/ipv4/route.c
removing useless govs