Greatly improve the boot-up unblocking time of the entropy device.

3 files changed, 19 insertions, 4 deletions

diff --git a/sys/dev/random/randomdev.c b/sys/dev/random/randomdev.c
index 13230db..37aeb3d 100644
--- a/sys/dev/random/randomdev.c
+++ b/sys/dev/random/randomdev.c
@@ -51,6 +51,7 @@
 #include "opt_noblockrandom.h"
 
 static d_open_t random_open;
+static d_close_t random_close;
 static d_read_t random_read;
 static d_write_t random_write;
 static d_ioctl_t random_ioctl;
@@ -62,7 +63,7 @@ static d_poll_t random_poll;
 
 static struct cdevsw random_cdevsw = {
 	/* open */	random_open,
-	/* close */	(d_close_t *)nullop,
+	/* close */	random_close,
 	/* read */	random_read,
 	/* write */	random_write,
 	/* ioctl */	random_ioctl,
@@ -104,6 +105,14 @@ random_open(dev_t dev, int flags, int fmt, struct proc *p)
 }
 
 static int
+random_close(dev_t dev, int flags, int fmt, struct proc *p)
+{
+	if ((flags & FWRITE) && (securelevel > 0 || suser(p)))
+		random_reseed();
+	return 0;
+}
+
+static int
 random_read(dev_t dev, struct uio *uio, int flag)
 {
 	u_int c, ret;
diff --git a/sys/dev/random/yarrow.c b/sys/dev/random/yarrow.c
index 8480897..c53e7c1 100644
--- a/sys/dev/random/yarrow.c
+++ b/sys/dev/random/yarrow.c
@@ -455,9 +455,6 @@ write_random(void *buf, u_int count)
 		random_harvest_internal(get_cyclecount(), (char *)buf + i, count,
 			0, 0, RANDOM_WRITE);
 	}
-
-	/* Explicit reseed */
-	reseed(FAST);
 }
 
 static void
@@ -527,3 +524,10 @@ random_harvest_internal(u_int64_t somecounter, void *entropy, u_int count,
 		mtx_exit(&random_harvest_mtx, MTX_DEF);
 	}
 }
+
+/* Helper routine to perform explicit reseeds */
+void
+random_reseed(void)
+{
+	reseed(FAST);
+}
diff --git a/sys/dev/random/yarrow.h b/sys/dev/random/yarrow.h
index 9904d24..49cc602 100644
--- a/sys/dev/random/yarrow.h
+++ b/sys/dev/random/yarrow.h
@@ -45,6 +45,8 @@ void random_init_harvester(void (*)(u_int64_t, void *, u_int, u_int, u_int, enum
 void random_deinit_harvester(void);
 void random_set_wakeup_exit(void *);
 
+void random_reseed(void);
+
 u_int read_random_real(void *, u_int);
 void write_random(void *, u_int);