diff options
| author |   Rasmus Villemoes <linux@rasmusvillemoes.dk> | 2018-03-01 00:22:47 +0100 |
|---|---|---|
| committer |   Theodore Ts'o <tytso@mit.edu> | 2018-02-28 19:03:19 -0500 |
| commit | 5e747dd9be54be190dd6ebeebf4a4a01ba765625 (patch) | |
| tree | 43d66c53cb93bd12976d8059653eb74ff7bebb11 /drivers/char | |
| parent | random: optimize add_interrupt_randomness (diff) | |
| download | linux-dev-5e747dd9be54be190dd6ebeebf4a4a01ba765625.tar.xz linux-dev-5e747dd9be54be190dd6ebeebf4a4a01ba765625.zip | |
drivers/char/random.c: remove unused dont_count_entropy
Ever since "random: kill dead extract_state struct" [1], the
dont_count_entropy member of struct timer_rand_state has been
effectively unused. Since it hasn't found a new use in 12 years, it's
probably safe to finally kill it.
[1] Pre-git, https://git.kernel.org/pub/scm/linux/kernel/git/tglx/history.git/commit/?id=c1c48e61c251f57e7a3f1bf11b3c462b2de9dcb5
Signed-off-by: Rasmus Villemoes <linux@rasmusvillemoes.dk>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Diffstat (limited to 'drivers/char')
| -rw-r--r-- | drivers/char/random.c | 53 |
1 files changed, 25 insertions, 28 deletions
diff --git a/drivers/char/random.c b/drivers/char/random.c index ee0c0d18f1eb..e027e7fa1472 100644 --- a/drivers/char/random.c +++ b/drivers/char/random.c @@ -964,7 +964,6 @@ static ssize_t extract_crng_user(void __user *buf, size_t nbytes) struct timer_rand_state { cycles_t last_time; long last_delta, last_delta2; - unsigned dont_count_entropy:1; }; #define INIT_TIMER_RAND_STATE { INITIAL_JIFFIES, }; @@ -1030,35 +1029,33 @@ static void add_timer_randomness(struct timer_rand_state *state, unsigned num) * We take into account the first, second and third-order deltas * in order to make our estimate. */ + delta = sample.jiffies - state->last_time; + state->last_time = sample.jiffies; + + delta2 = delta - state->last_delta; + state->last_delta = delta; + + delta3 = delta2 - state->last_delta2; + state->last_delta2 = delta2; + + if (delta < 0) + delta = -delta; + if (delta2 < 0) + delta2 = -delta2; + if (delta3 < 0) + delta3 = -delta3; + if (delta > delta2) + delta = delta2; + if (delta > delta3) + delta = delta3; - if (!state->dont_count_entropy) { - delta = sample.jiffies - state->last_time; - state->last_time = sample.jiffies; - - delta2 = delta - state->last_delta; - state->last_delta = delta; - - delta3 = delta2 - state->last_delta2; - state->last_delta2 = delta2; - - if (delta < 0) - delta = -delta; - if (delta2 < 0) - delta2 = -delta2; - if (delta3 < 0) - delta3 = -delta3; - if (delta > delta2) - delta = delta2; - if (delta > delta3) - delta = delta3; + /* + * delta is now minimum absolute delta. + * Round down by 1 bit on general principles, + * and limit entropy entimate to 12 bits. + */ + credit_entropy_bits(r, min_t(int, fls(delta>>1), 11)); - /* - * delta is now minimum absolute delta. - * Round down by 1 bit on general principles, - * and limit entropy entimate to 12 bits. - */ - credit_entropy_bits(r, min_t(int, fls(delta>>1), 11)); - } preempt_enable(); } |