lightnvm: set default lun range when no luns are specified

The create target ioctl takes a lun begin and lun end parameter, which
defines the range of luns to initialize a target with. If the user does
not set the parameters, it default to only using lun 0. Instead,
defaults to use all luns in the OCSSD, as it is the usual behaviour
users want.

Signed-off-by: Matias Bjørling <matias@cnexlabs.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
diff --git a/drivers/lightnvm/core.c b/drivers/lightnvm/core.c
index 6ce76c0..5262ba6 100644
--- a/drivers/lightnvm/core.c
+++ b/drivers/lightnvm/core.c
@@ -1102,6 +1102,11 @@
 	}
 	s = &create->conf.s;
 
+	if (s->lun_begin == -1 && s->lun_end == -1) {
+		s->lun_begin = 0;
+		s->lun_end = dev->geo.nr_luns - 1;
+	}
+
 	if (s->lun_begin > s->lun_end || s->lun_end >= dev->geo.nr_luns) {
 		pr_err("nvm: lun out of bound (%u:%u > %u)\n",
 			s->lun_begin, s->lun_end, dev->geo.nr_luns - 1);