From: Torsten Duwe <duwe@lst.de>
Date: Sun, 15 Jun 2014 03:46:03 +0000 (-0400)
Subject: hwrng: create filler thread
X-Git-Tag: omap-for-v3.17/fixes-against-rc2~106^2~5
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=be4000bc4644d027c519b6361f5ae3bbfc52c347;p=pandora-kernel.git

hwrng: create filler thread

This can be viewed as the in-kernel equivalent of hwrngd;
like FUSE it is a good thing to have a mechanism in user land,
but for some reasons (simplicity, secrecy, integrity, speed)
it may be better to have it in kernel space.

This patch creates a thread once a hwrng registers, and uses
the previously established add_hwgenerator_randomness() to feed
its data to the input pool as long as needed. A derating factor
is used to bias the entropy estimation and to disable this
mechanism entirely when set to zero.

Signed-off-by: Torsten Duwe <duwe@suse.de>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Acked-by: H. Peter Anvin <hpa@zytor.com>
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