jitterentropy: `jent_mod_init()` takes 17 ms

[Paul Menzel]

Dear Linux folks,


By mistake I built `XFRM_ESP` into the Linux kernel, resulting in

    CONFIG_CRYPTO_SEQIV=y
    CONFIG_CRYPTO_ECHAINIV=y

and also the Jitterentropy RNG to be built in.

    CRYPTO_JITTERENTROPY=y

So, on the Asus F2A85-M PRO starting Linux 4.10-rc3 with 
`initcall_debug`, the init method is run unconditionally, and it takes 
17.5 ms, which is over ten percent of the overall 900 ms the Linux 
kernel needs until loading the init process.

    [    0.300544] calling  jent_mod_init+0x0/0x2c @ 1
    [    0.318438] initcall jent_mod_init+0x0/0x2c returned 0 after 
17471 usecs

Looking at the output of systemd-bootchart, it looks like, that this 
indeed delayed the boot a little, as the other init methods seem to be 
ordered after it.

I am now building it as a module, but am wondering if the time can be 
reduced to below ten milliseconds.


Kind regards,

Paul