[PATCH 4.9 109/264] random: only call crng_finalize_init() for primary_crng

Greg Kroah-Hartman
2022-06-23T16:54:49Z

From: Dominik Brodowski <linux@dominikbrodowski.net>

commit 9d5505f1eebeca778074a0260ed077fd85f8792c upstream.

crng_finalize_init() returns instantly if it is called for another pool
than primary_crng. The test whether crng_finalize_init() is still required
can be moved to the relevant caller in crng_reseed(), and
crng_need_final_init can be reset to false if crng_finalize_init() is
called with workqueues ready. Then, no previous callsite will call
crng_finalize_init() unless it is needed, and we can get rid of the
superfluous function parameter.

Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/char/random.c | 10 +++++-----
1 file changed, 5 insertions(+), 5 deletions(-)

--- a/drivers/char/random.c
+++ b/drivers/char/random.c
@@ -800,10 +800,8 @@ static void __init crng_initialize_prima
primary_crng.init_time = jiffies - CRNG_RESEED_INTERVAL - 1;
}

-static void crng_finalize_init(struct crng_state *crng)
+static void crng_finalize_init(void)
{
- if (crng != &primary_crng || crng_init >= 2)
- return;
if (!system_wq) {
/* We can't call numa_crng_init until we have workqueues,
* so mark this for processing later. */
@@ -814,6 +812,7 @@ static void crng_finalize_init(struct cr
invalidate_batched_entropy();
numa_crng_init();
crng_init = 2;
+ crng_need_final_init = false;
process_random_ready_list();
wake_up_interruptible(&crng_init_wait);
kill_fasync(&fasync, SIGIO, POLL_IN);
@@ -1031,7 +1030,8 @@ static void crng_reseed(struct crng_stat
memzero_explicit(&buf, sizeof(buf));
WRITE_ONCE(crng->init_time, jiffies);
spin_unlock_irqrestore(&crng->lock, flags);
- crng_finalize_init(crng);
+ if (crng == &primary_crng && crng_init < 2)
+ crng_finalize_init();
}

static void _extract_crng(struct crng_state *crng, u8 out[CHACHA20_BLOCK_SIZE])
@@ -1748,7 +1748,7 @@ int __init rand_initialize(void)
{
init_std_data();
if (crng_need_final_init)
- crng_finalize_init(&primary_crng);
+ crng_finalize_init();
crng_initialize_primary();
crng_global_init_time = jiffies;
if (ratelimit_disable) {