[PATCH 5.4 015/240] random: delete code to pull data into pools

Greg Kroah-Hartman
2022-06-20T13:30:50Z

From: Andy Lutomirski <luto@kernel.org>

commit 84df7cdfbb215a34657b39f4257dab739efa2df9 upstream.

There is no pool that pulls, so it was just dead code.

Signed-off-by: Andy Lutomirski <luto@kernel.org>
Link: https://lore.kernel.org/r/4a05fe0c7a5c831389ef4aea51d24528ac8682c7.1577088521.git.luto@kernel.org
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/char/random.c | 40 ----------------------------------------
1 file changed, 40 deletions(-)

--- a/drivers/char/random.c
+++ b/drivers/char/random.c
@@ -529,10 +529,8 @@ struct entropy_store {
const struct poolinfo *poolinfo;
__u32 *pool;
const char *name;
- struct entropy_store *pull;

/* read-write data: */
- unsigned long last_pulled;
spinlock_t lock;
unsigned short add_ptr;
unsigned short input_rotate;
@@ -1368,41 +1366,6 @@ EXPORT_SYMBOL_GPL(add_disk_randomness);
*********************************************************************/

/*
- * This utility inline function is responsible for transferring entropy
- * from the primary pool to the secondary extraction pool. We make
- * sure we pull enough for a 'catastrophic reseed'.
- */
-static void _xfer_secondary_pool(struct entropy_store *r, size_t nbytes);
-static void xfer_secondary_pool(struct entropy_store *r, size_t nbytes)
-{
- if (!r->pull ||
- r->entropy_count >= (nbytes << (ENTROPY_SHIFT + 3)) ||
- r->entropy_count > r->poolinfo->poolfracbits)
- return;
-
- _xfer_secondary_pool(r, nbytes);
-}
-
-static void _xfer_secondary_pool(struct entropy_store *r, size_t nbytes)
-{
- __u32 tmp[OUTPUT_POOL_WORDS];
-
- int bytes = nbytes;
-
- /* pull at least as much as a wakeup */
- bytes = max_t(int, bytes, random_read_wakeup_bits / 8);
- /* but never more than the buffer size */
- bytes = min_t(int, bytes, sizeof(tmp));
-
- trace_xfer_secondary_pool(r->name, bytes * 8, nbytes * 8,
- ENTROPY_BITS(r), ENTROPY_BITS(r->pull));
- bytes = extract_entropy(r->pull, tmp, bytes,
- random_read_wakeup_bits / 8, 0);
- mix_pool_bytes(r, tmp, bytes);
- credit_entropy_bits(r, bytes*8);
-}
-
-/*
* This function decides how many bytes to actually take from the
* given pool, and also debits the entropy count accordingly.
*/
@@ -1565,7 +1528,6 @@ static ssize_t extract_entropy(struct en
spin_unlock_irqrestore(&r->lock, flags);
trace_extract_entropy(r->name, EXTRACT_SIZE,
ENTROPY_BITS(r), _RET_IP_);
- xfer_secondary_pool(r, EXTRACT_SIZE);
extract_buf(r, tmp);
spin_lock_irqsave(&r->lock, flags);
memcpy(r->last_data, tmp, EXTRACT_SIZE);
@@ -1574,7 +1536,6 @@ static ssize_t extract_entropy(struct en
}

trace_extract_entropy(r->name, nbytes, ENTROPY_BITS(r), _RET_IP_);
- xfer_secondary_pool(r, nbytes);
nbytes = account(r, nbytes, min, reserved);

return _extract_entropy(r, buf, nbytes, fips_enabled);
@@ -1846,7 +1807,6 @@ static void __init init_std_data(struct
ktime_t now = ktime_get_real();
unsigned long rv;

- r->last_pulled = jiffies;
mix_pool_bytes(r, &now, sizeof(now));
for (i = r->poolinfo->poolbytes; i > 0; i -= sizeof(rv)) {
if (!arch_get_random_seed_long(&rv) &&