linux-kernel - [PATCH] random: remove use_input_pool parameter from crng

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Date:   Fri,  4 Feb 2022 14:17:33 -0800
From:   Eric Biggers <ebiggers@...nel.org>
To:     "Jason A . Donenfeld " <Jason@...c4.com>,
        Theodore Ts'o <tytso@....edu>
Cc:     linux-crypto@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [PATCH] random: remove use_input_pool parameter from crng_reseed()

From: Eric Biggers <ebiggers@...gle.com>

The primary_crng is always reseeded from the input_pool, while the NUMA
crngs are always reseeded from the primary_crng.  Remove the redundant
'use_input_pool' parameter from crng_reseed() and just directly check
whether the crng is the primary_crng.

Signed-off-by: Eric Biggers <ebiggers@...gle.com>
---
 drivers/char/random.c | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/drivers/char/random.c b/drivers/char/random.c
index e16cf254db15..964bce981235 100644
--- a/drivers/char/random.c
+++ b/drivers/char/random.c
@@ -371,7 +371,7 @@ static struct {
 
 static void extract_entropy(void *buf, size_t nbytes);
 
-static void crng_reseed(struct crng_state *crng, bool use_input_pool);
+static void crng_reseed(struct crng_state *crng);
 
 /*
  * This function adds bytes into the entropy "pool".  It does not
@@ -470,7 +470,7 @@ static void credit_entropy_bits(int nbits)
 	trace_credit_entropy_bits(nbits, entropy_count, _RET_IP_);
 
 	if (crng_init < 2 && entropy_count >= POOL_MIN_BITS)
-		crng_reseed(&primary_crng, true);
+		crng_reseed(&primary_crng);
 }
 
 /*********************************************************************
@@ -707,7 +707,7 @@ static int crng_slow_load(const u8 *cp, size_t len)
 	return 1;
 }
 
-static void crng_reseed(struct crng_state *crng, bool use_input_pool)
+static void crng_reseed(struct crng_state *crng)
 {
 	unsigned long flags;
 	int i;
@@ -716,7 +716,7 @@ static void crng_reseed(struct crng_state *crng, bool use_input_pool)
 		u32 key[8];
 	} buf;
 
-	if (use_input_pool) {
+	if (crng == &primary_crng) {
 		int entropy_count;
 		do {
 			entropy_count = READ_ONCE(input_pool.entropy_count);
@@ -756,7 +756,7 @@ static void _extract_crng(struct crng_state *crng, u8 out[CHACHA_BLOCK_SIZE])
 		init_time = READ_ONCE(crng->init_time);
 		if (time_after(READ_ONCE(crng_global_init_time), init_time) ||
 		    time_after(jiffies, init_time + CRNG_RESEED_INTERVAL))
-			crng_reseed(crng, crng == &primary_crng);
+			crng_reseed(crng);
 	}
 	spin_lock_irqsave(&crng->lock, flags);
 	chacha20_block(&crng->state[0], out);
@@ -1555,7 +1555,7 @@ static long random_ioctl(struct file *f, unsigned int cmd, unsigned long arg)
 			return -EPERM;
 		if (crng_init < 2)
 			return -ENODATA;
-		crng_reseed(&primary_crng, true);
+		crng_reseed(&primary_crng);
 		WRITE_ONCE(crng_global_init_time, jiffies - 1);
 		return 0;
 	default:

base-commit: 4bccade22d405309cbc588094f956f4d310e4677
-- 
2.35.1