random32: add prandom_reseed_late() and call when nonblocking pool becomes initialized

[~andy/linux] / lib / random32.c

diff --git a/lib/random32.c b/lib/random32.c
index 12215df701e87441bc0b8b09340dac815594463a..9f2f2fb03dfe83bac0529bfd9db11416e59ad91b 100644 (file)
--- a/lib/random32.c
+++ b/lib/random32.c
@@ -200,9 +200,18 @@ static void prandom_start_seed_timer(void)
  *     Generate better values after random number generator
  *     is fully initialized.
  */
-static int __init prandom_reseed(void)
+static void __prandom_reseed(bool late)
 {
        int i;
+       unsigned long flags;
+       static bool latch = false;
+       static DEFINE_SPINLOCK(lock);
+
+       /* only allow initial seeding (late == false) once */
+       spin_lock_irqsave(&lock, flags);
+       if (latch && !late)
+               goto out;
+       latch = true;
 
        for_each_possible_cpu(i) {
                struct rnd_state *state = &per_cpu(net_rand_state,i);
@@ -216,6 +225,18 @@ static int __init prandom_reseed(void)
                /* mix it in */
                prandom_u32_state(state);
        }
+out:
+       spin_unlock_irqrestore(&lock, flags);
+}
+
+void prandom_reseed_late(void)
+{
+       __prandom_reseed(true);
+}
+
+static int __init prandom_reseed(void)
+{
+       __prandom_reseed(false);
        prandom_start_seed_timer();
        return 0;
 }