Attempts to make this device Giant-free were ill-conceived as

uiomove(9) is not properly locked. So, return to NEEDGIANT
mode. Later, when uiomove is finely locked, I'll revisit.

While I'm here, provide some temporary debugging output to
help catch blocking startups.

2 files changed, 9 insertions, 14 deletions

diff --git a/sys/dev/random/randomdev.c b/sys/dev/random/randomdev.c
index 268159a..c966097 100644
--- a/sys/dev/random/randomdev.c
+++ b/sys/dev/random/randomdev.c
@@ -61,6 +61,7 @@ static d_poll_t random_poll;
 
 static struct cdevsw random_cdevsw = {
 	.d_version = D_VERSION,
+	.d_flags = D_NEEDGIANT,
 	.d_close = random_close,
 	.d_read = random_read,
 	.d_write = random_write,
@@ -89,11 +90,10 @@ random_close(dev_t dev __unused, int flags, int fmt __unused,
 {
 	if ((flags & FWRITE) && (suser(td) == 0)
 	    && (securelevel_gt(td->td_ucred, 0) == 0)) {
-		mtx_lock(&random_systat.lock);
 		(*random_systat.reseed)();
 		random_systat.seeded = 1;
-		mtx_unlock(&random_systat.lock);
 	}
+
 	return (0);
 }
 
@@ -103,15 +103,17 @@ random_read(dev_t dev __unused, struct uio *uio, int flag)
 {
 	int c, error = 0;
 
-	mtx_lock(&random_systat.lock);
-
 	/* Blocking logic */
 	while (!random_systat.seeded && !error) {
 		if (flag & IO_NDELAY)
 			error = EWOULDBLOCK;
-		else
-			error = msleep(&random_systat, &random_systat.lock,
+		else {
+			/* No complaints please. This is temporary! */
+			printf("Entropy device is blocking. "
+			    "Dance fandango on keyboard to unblock.\n");
+			error = tsleep(&random_systat,
 			    PUSER | PCATCH, "block", 0);
+		}
 	}
 
 	/* The actual read */
@@ -123,8 +125,6 @@ random_read(dev_t dev __unused, struct uio *uio, int flag)
 		}
 	}
 
-	mtx_unlock(&random_systat.lock);
-
 	return (error);
 }
 
@@ -134,7 +134,6 @@ random_write(dev_t dev __unused, struct uio *uio, int flag __unused)
 {
 	int c, error = 0;
 
-	mtx_lock(&random_systat.lock);
 	while (uio->uio_resid > 0) {
 		c = MIN((int)uio->uio_resid, PAGE_SIZE);
 		error = uiomove(random_buf, c, uio);
@@ -142,7 +141,7 @@ random_write(dev_t dev __unused, struct uio *uio, int flag __unused)
 			break;
 		(*random_systat.write)(random_buf, c);
 	}
-	mtx_unlock(&random_systat.lock);
+
 	return (error);
 }
 
@@ -189,8 +188,6 @@ random_modevent(module_t mod __unused, int type, void *data __unused)
 	case MOD_LOAD:
 		random_buf = (void *)malloc(PAGE_SIZE, M_TEMP, M_WAITOK);
 		random_ident_hardware(&random_systat);
-		mtx_init(&random_systat.lock, "entropy device lock",
-		    NULL, MTX_DEF);
 		(*random_systat.init)();
 
 		printf("random: <entropy source, %s>\n", random_systat.ident);
@@ -204,7 +201,6 @@ random_modevent(module_t mod __unused, int type, void *data __unused)
 	case MOD_UNLOAD:
 		(*random_systat.deinit)();
 		free(random_buf, M_TEMP);
-		mtx_destroy(&random_systat.lock);
 
 		destroy_dev(random_dev);
 
diff --git a/sys/dev/random/randomdev.h b/sys/dev/random/randomdev.h
index d5e064f..bf13e1b 100644
--- a/sys/dev/random/randomdev.h
+++ b/sys/dev/random/randomdev.h
@@ -45,7 +45,6 @@ struct random_systat {
 	random_read_func_t	*read;
 	random_write_func_t	*write;
 	random_reseed_func_t	*reseed;
-	struct mtx		lock;
 };
 
 extern struct random_systat random_systat;