random: do not take pool spinlock at boot

commit afba0b80b977b2a8f16234f2acd982f82710ba33 upstream.

Since rand_initialize() is run while interrupts are still off and
nothing else is running, we don't need to repeatedly take and release
the pool spinlock, especially in the RDSEED loop.

Reviewed-by: Eric Biggers <ebiggers@google.com>
Reviewed-by: Dominik Brodowski <linux@dominikbrodowski.net>
Signed-off-by: Jason A. Donenfeld <Jason@zx2c4.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/char/random.c b/drivers/char/random.c
index 8728de2f445087aaea6730b697c1de4e1c395ad2..1d0249e017d0cda63ea92ff3fa55dc8e93aeac20 100644 (file)
--- a/drivers/char/random.c
+++ b/drivers/char/random.c
@@ -978,10 +978,10 @@ int __init rand_initialize(void)
                        rv = random_get_entropy();
                        arch_init = false;
                }
-               mix_pool_bytes(&rv, sizeof(rv));
+               _mix_pool_bytes(&rv, sizeof(rv));
        }
-       mix_pool_bytes(&now, sizeof(now));
-       mix_pool_bytes(utsname(), sizeof(*(utsname())));
+       _mix_pool_bytes(&now, sizeof(now));
+       _mix_pool_bytes(utsname(), sizeof(*(utsname())));
 
        extract_entropy(base_crng.key, sizeof(base_crng.key));
        ++base_crng.generation;