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authorLinus Torvalds <torvalds@linux-foundation.org>2018-04-05 00:31:53 +0300
committerLinus Torvalds <torvalds@linux-foundation.org>2018-04-05 00:31:53 +0300
commit0c21fd6e659342d6b6bb4b4c9ddc0f1c38b5216e (patch)
tree3f993ae0ff904c55b8ec8b0d44f2d4a4b4c3857e
parent3e968c9f1401088abc9a19ae6ff571644d37a355 (diff)
parent5e747dd9be54be190dd6ebeebf4a4a01ba765625 (diff)
downloadlinux-0c21fd6e659342d6b6bb4b4c9ddc0f1c38b5216e.tar.xz
Merge tag 'random_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/random
Pull /dev/random updates from Ted Ts'o: "A few random (cough, cough) cleanups for the /dev/random driver" * tag 'random_for_linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/random: drivers/char/random.c: remove unused dont_count_entropy random: optimize add_interrupt_randomness random: always fill buffer in get_random_bytes_wait random: use a tighter cap in credit_entropy_bits_safe()
-rw-r--r--drivers/char/random.c58
-rw-r--r--include/linux/random.h4
2 files changed, 29 insertions, 33 deletions
diff --git a/drivers/char/random.c b/drivers/char/random.c
index e5b3d3ba4660..e027e7fa1472 100644
--- a/drivers/char/random.c
+++ b/drivers/char/random.c
@@ -709,7 +709,8 @@ retry:
}
/* should we wake readers? */
- if (entropy_bits >= random_read_wakeup_bits) {
+ if (entropy_bits >= random_read_wakeup_bits &&
+ wq_has_sleeper(&random_read_wait)) {
wake_up_interruptible(&random_read_wait);
kill_fasync(&fasync, SIGIO, POLL_IN);
}
@@ -732,7 +733,7 @@ retry:
static int credit_entropy_bits_safe(struct entropy_store *r, int nbits)
{
- const int nbits_max = (int)(~0U >> (ENTROPY_SHIFT + 1));
+ const int nbits_max = r->poolinfo->poolwords * 32;
if (nbits < 0)
return -EINVAL;
@@ -963,7 +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, };
@@ -1029,35 +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();
}
diff --git a/include/linux/random.h b/include/linux/random.h
index 4024f7d9c77d..2ddf13b4281e 100644
--- a/include/linux/random.h
+++ b/include/linux/random.h
@@ -85,10 +85,8 @@ static inline unsigned long get_random_canary(void)
static inline int get_random_bytes_wait(void *buf, int nbytes)
{
int ret = wait_for_random_bytes();
- if (unlikely(ret))
- return ret;
get_random_bytes(buf, nbytes);
- return 0;
+ return ret;
}
#define declare_get_random_var_wait(var) \