FreeBSD: Replace legacy make_dev() interface usage

The function make_dev_s() was introduced to replace make_dev() in
FreeBSD 11.0.  It allows further specification of properties and flags
and returns an error code on failure.  Using this we can fail loading
the module more gracefully than a panic in situations such as when a
device named zfs already exists.  We already use it for zvols.

Use make_dev_s() for /dev/zfs.

Reviewed-by: Alexander Motin <[email protected]>
Signed-off-by: Ryan Moeller <[email protected]>
Closes #13854

Author: Ryan Moeller

module/os/freebsd/zfs/kmod_core.c

@@ -219,9 +219,16 @@ static struct cdevsw zfs_cdevsw = {
 int
 zfsdev_attach(void)
 {
-	zfsdev = make_dev(&zfs_cdevsw, 0x0, UID_ROOT, GID_OPERATOR, 0666,
-	    ZFS_DRIVER);
-	return (0);
+	struct make_dev_args args;
+
+	make_dev_args_init(&args);
+	args.mda_flags = MAKEDEV_CHECKNAME | MAKEDEV_WAITOK;
+	args.mda_devsw = &zfs_cdevsw;
+	args.mda_cr = NULL;
+	args.mda_uid = UID_ROOT;
+	args.mda_gid = GID_OPERATOR;
+	args.mda_mode = 0666;
+	return (make_dev_s(&args, &zfsdev, ZFS_DRIVER));
 }
 
 void