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Commit 61f87ea3 authored by Jason A. Donenfeld's avatar Jason A. Donenfeld Committed by Greg Kroah-Hartman
Browse files

Revert "random: use static branch for crng_ready()" 



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: default avatarJason A. Donenfeld <Jason@zx2c4.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 3faf33a8

drivers/char/random.c

+2 −10
Original line number Diff line number Diff line
@@ -79,8 +79,7 @@ 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;
@@ -110,11 +109,6 @@ 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);
@@ -268,7 +262,7 @@ 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));
@@ -709,7 +703,6 @@ static void extract_entropy(void *buf, size_t len) 


static void __cold _credit_init_bits(size_t bits)

{

	static struct execute_work set_ready;

	unsigned int new, orig, add;

	unsigned long flags;
@@ -725,7 +718,6 @@ static void __cold _credit_init_bits(size_t bits) 


	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);