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>

diff --git a/drivers/char/random.c b/drivers/char/random.c
index ee0c0d1..e027e7f 100644 (file)
--- 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();
 }