Original cryptd thread implementation has scalability issue, this
patch solve the issue with a per-CPU thread implementation.

struct cryptd_queue is defined to be a per-CPU queue, which holds one
struct cryptd_cpu_queue for each CPU. In struct cryptd_cpu_queue, a
struct crypto_queue holds all requests for the CPU, a struct
work_struct is used to run all requests for the CPU.

Testing based on dm-crypt on an Intel Core 2 E6400 (two cores) machine
shows 19.2% performance gain. The testing script is as follow:

-------------------- script begin ---------------------------
#!/bin/sh

dmc_create()
{
        # Create a crypt device using dmsetup
        dmsetup create $2 --table "0 `blockdev --getsize $1` crypt cbc(aes-asm)?cryptd?plain:plain babebabebabebabebabebabebabebabe 0 $1 0"
}

dmsetup remove crypt0
dmsetup remove crypt1

dd if=/dev/zero of=/dev/ram0 bs=1M count=4 >& /dev/null
dd if=/dev/zero of=/dev/ram1 bs=1M count=4 >& /dev/null

dmc_create /dev/ram0 crypt0
dmc_create /dev/ram1 crypt1

cat >tr.sh <<EOF
#!/bin/sh

for n in \$(seq 10); do
        dd if=/dev/dm-0 of=/dev/null >& /dev/null &
        dd if=/dev/dm-1 of=/dev/null >& /dev/null &
done
wait
EOF

for n in $(seq 10); do
        /usr/bin/time sh tr.sh
done
rm tr.sh
-------------------- script end   ---------------------------

The separator of dm-crypt parameter is changed from "-" to "?", because
"-" is used in some cipher driver name too, and cryptds need to specify
cipher driver name instead of cipher name.

The test result on an Intel Core2 E6400 (two cores) is as follow:

without patch:
-----------------wo begin --------------------------
0.04user 0.38system 0:00.39elapsed 107%CPU (0avgtext+0avgdata 0maxresident)k
0inputs+0outputs (0major+6566minor)pagefaults 0swaps
0.07user 0.35system 0:00.35elapsed 121%CPU (0avgtext+0avgdata 0maxresident)k
0inputs+0outputs (0major+6567minor)pagefaults 0swaps
0.06user 0.34system 0:00.30elapsed 135%CPU (0avgtext+0avgdata 0maxresident)k
0inputs+0outputs (0major+6562minor)pagefaults 0swaps
0.05user 0.37system 0:00.36elapsed 119%CPU (0avgtext+0avgdata 0maxresident)k
0inputs+0outputs (0major+6607minor)pagefaults 0swaps
0.06user 0.36system 0:00.35elapsed 120%CPU (0avgtext+0avgdata 0maxresident)k
0inputs+0outputs (0major+6562minor)pagefaults 0swaps
0.05user 0.37system 0:00.31elapsed 136%CPU (0avgtext+0avgdata 0maxresident)k
0inputs+0outputs (0major+6594minor)pagefaults 0swaps
0.04user 0.34system 0:00.30elapsed 126%CPU (0avgtext+0avgdata 0maxresident)k
0inputs+0outputs (0major+6597minor)pagefaults 0swaps
0.06user 0.32system 0:00.31elapsed 125%CPU (0avgtext+0avgdata 0maxresident)k
0inputs+0outputs (0major+6571minor)pagefaults 0swaps
0.06user 0.34system 0:00.31elapsed 134%CPU (0avgtext+0avgdata 0maxresident)k
0inputs+0outputs (0major+6581minor)pagefaults 0swaps
0.05user 0.38system 0:00.31elapsed 138%CPU (0avgtext+0avgdata 0maxresident)k
0inputs+0outputs (0major+6600minor)pagefaults 0swaps
-----------------wo end   --------------------------


with patch:
------------------w begin --------------------------
0.02user 0.31system 0:00.24elapsed 141%CPU (0avgtext+0avgdata 0maxresident)k
0inputs+0outputs (0major+6554minor)pagefaults 0swaps
0.05user 0.34system 0:00.31elapsed 127%CPU (0avgtext+0avgdata 0maxresident)k
0inputs+0outputs (0major+6606minor)pagefaults 0swaps
0.07user 0.33system 0:00.26elapsed 155%CPU (0avgtext+0avgdata 0maxresident)k
0inputs+0outputs (0major+6559minor)pagefaults 0swaps
0.07user 0.32system 0:00.26elapsed 151%CPU (0avgtext+0avgdata 0maxresident)k
0inputs+0outputs (0major+6562minor)pagefaults 0swaps
0.05user 0.34system 0:00.26elapsed 150%CPU (0avgtext+0avgdata 0maxresident)k
0inputs+0outputs (0major+6603minor)pagefaults 0swaps
0.03user 0.36system 0:00.31elapsed 124%CPU (0avgtext+0avgdata 0maxresident)k
0inputs+0outputs (0major+6562minor)pagefaults 0swaps
0.04user 0.35system 0:00.26elapsed 147%CPU (0avgtext+0avgdata 0maxresident)k
0inputs+0outputs (0major+6586minor)pagefaults 0swaps
0.03user 0.37system 0:00.27elapsed 146%CPU (0avgtext+0avgdata 0maxresident)k
0inputs+0outputs (0major+6562minor)pagefaults 0swaps
0.04user 0.36system 0:00.26elapsed 154%CPU (0avgtext+0avgdata 0maxresident)k
0inputs+0outputs (0major+6594minor)pagefaults 0swaps
0.04user 0.35system 0:00.26elapsed 154%CPU (0avgtext+0avgdata 0maxresident)k
0inputs+0outputs (0major+6557minor)pagefaults 0swaps
------------------w end   --------------------------

The middle value of elapsed time is:
wo cryptwq: 0.31
w  cryptwq: 0.26

The performance gain is about (0.31-0.26)/0.26 = 0.192.
Signed-off-by: NHuang Ying <ying.huang@intel.com>
Signed-off-by: NHerbert Xu <herbert@gondor.apana.org.au>