[PATCH v2 6/7] random: Delete code to pull data into pools

[Andy Lutomirski]

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

Signed-off-by: Andy Lutomirski <l...@kernel.org>
---
 drivers/char/random.c | 40 ----------------------------------------
 1 file changed, 40 deletions(-)

diff --git a/drivers/char/random.c b/drivers/char/random.c
index 4521138231ed..99fea5cc29a8 100644
--- a/drivers/char/random.c
+++ b/drivers/char/random.c
@@ -528,10 +528,8 @@ 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;
@@ -1347,41 +1345,6 @@ 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.
@@ -1545,7 +1508,6 @@ static ssize_t extract_entropy(struct entropy_store *r, 
void *buf,
                        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);
@@ -1554,7 +1516,6 @@ static ssize_t extract_entropy(struct entropy_store *r, 
void *buf,
        }
 
        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);
@@ -1765,7 +1726,6 @@ static void __init init_std_data(struct entropy_store *r)
        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) &&
-- 
2.21.0