[PATCH 5.18 866/879] Revert "random: use static branch for crng_ready()"

Greg Kroah-Hartman
2022-06-08T01:38:21Z

From: "Jason A. Donenfeld" <Jason@zx2c4.com>

This reverts upstream commit f5bda35fba615ace70a656d4700423fa6c9bebee
from stable. It's not essential and will take some time during 5.19 to
work out properly.

Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
---
drivers/char/random.c | 12 ++----------
1 file changed, 2 insertions(+), 10 deletions(-)

--- a/drivers/char/random.c
+++ b/drivers/char/random.c
@@ -78,8 +78,7 @@ static enum {
CRNG_EARLY = 1, /* At least POOL_EARLY_BITS collected */
CRNG_READY = 2 /* Fully initialized with POOL_READY_BITS collected */
} crng_init __read_mostly = CRNG_EMPTY;
-static DEFINE_STATIC_KEY_FALSE(crng_is_ready);
-#define crng_ready() (static_branch_likely(&crng_is_ready) || crng_init >= CRNG_READY)
+#define crng_ready() (likely(crng_init >= CRNG_READY))
/* Various types of waiters for crng_init->CRNG_READY transition. */
static DECLARE_WAIT_QUEUE_HEAD(crng_init_wait);
static struct fasync_struct *fasync;
@@ -109,11 +108,6 @@ bool rng_is_initialized(void)
}
EXPORT_SYMBOL(rng_is_initialized);

-static void __cold crng_set_ready(struct work_struct *work)
-{
- static_branch_enable(&crng_is_ready);
-}
-
/* Used by wait_for_random_bytes(), and considered an entropy collector, below. */
static void try_to_generate_entropy(void);

@@ -267,7 +261,7 @@ static void crng_reseed(void)
++next_gen;
WRITE_ONCE(base_crng.generation, next_gen);
WRITE_ONCE(base_crng.birth, jiffies);
- if (!static_branch_likely(&crng_is_ready))
+ if (!crng_ready())
crng_init = CRNG_READY;
spin_unlock_irqrestore(&base_crng.lock, flags);
memzero_explicit(key, sizeof(key));
@@ -710,7 +704,6 @@ static void extract_entropy(void *buf, s

static void __cold _credit_init_bits(size_t bits)
{
- static struct execute_work set_ready;
unsigned int new, orig, add;
unsigned long flags;

@@ -726,7 +719,6 @@ static void __cold _credit_init_bits(siz

if (orig < POOL_READY_BITS && new >= POOL_READY_BITS) {
crng_reseed(); /* Sets crng_init to CRNG_READY under base_crng.lock. */
- execute_in_process_context(crng_set_ready, &set_ready);
process_random_ready_list();
wake_up_interruptible(&crng_init_wait);
kill_fasync(&fasync, SIGIO, POLL_IN);