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authorTheodore Ts'o <tytso@mit.edu>2012-07-02 13:52:16 +0200
committerTheodore Ts'o <tytso@mit.edu>2012-07-15 02:17:28 +0200
commit775f4b297b780601e61787b766f306ed3e1d23eb (patch)
treee97e21669f0719636ccac0219f617bad6a0e8b54 /drivers/mfd
parentrandom: fix up sparse warnings (diff)
downloadlinux-775f4b297b780601e61787b766f306ed3e1d23eb.tar.xz
linux-775f4b297b780601e61787b766f306ed3e1d23eb.zip
random: make 'add_interrupt_randomness()' do something sane
We've been moving away from add_interrupt_randomness() for various reasons: it's too expensive to do on every interrupt, and flooding the CPU with interrupts could theoretically cause bogus floods of entropy from a somewhat externally controllable source. This solves both problems by limiting the actual randomness addition to just once a second or after 64 interrupts, whicever comes first. During that time, the interrupt cycle data is buffered up in a per-cpu pool. Also, we make sure the the nonblocking pool used by urandom is initialized before we start feeding the normal input pool. This assures that /dev/urandom is returning unpredictable data as soon as possible. (Based on an original patch by Linus, but significantly modified by tytso.) Tested-by: Eric Wustrow <ewust@umich.edu> Reported-by: Eric Wustrow <ewust@umich.edu> Reported-by: Nadia Heninger <nadiah@cs.ucsd.edu> Reported-by: Zakir Durumeric <zakir@umich.edu> Reported-by: J. Alex Halderman <jhalderm@umich.edu>. Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: "Theodore Ts'o" <tytso@mit.edu> Cc: stable@vger.kernel.org
Diffstat (limited to 'drivers/mfd')
-rw-r--r--drivers/mfd/ab3100-core.c2
1 files changed, 0 insertions, 2 deletions
diff --git a/drivers/mfd/ab3100-core.c b/drivers/mfd/ab3100-core.c
index 1efad20fb175..9522d6bda4f7 100644
--- a/drivers/mfd/ab3100-core.c
+++ b/drivers/mfd/ab3100-core.c
@@ -409,8 +409,6 @@ static irqreturn_t ab3100_irq_handler(int irq, void *data)
u32 fatevent;
int err;
- add_interrupt_randomness(irq);
-
err = ab3100_get_register_page_interruptible(ab3100, AB3100_EVENTA1,
event_regs, 3);
if (err)