Implement MDIOCLIST which returns the unit numbers of configured md(4)

devices.

We use the md_pad[] array and if there are more units than its size the
last returned unit number will be -1, but the number of units returned
is correct.

1 files changed, 11 insertions, 0 deletions

diff --git a/sys/dev/md/md.c b/sys/dev/md/md.c
index 4befee3..f405b62 100644
--- a/sys/dev/md/md.c
+++ b/sys/dev/md/md.c
@@ -1133,6 +1133,7 @@ mdctlioctl(dev_t dev, u_long cmd, caddr_t addr, int flags, struct thread *td)
 {
 	struct md_ioctl *mdio;
 	struct md_s *sc;
+	int i;
 
 	if (md_debug)
 		printf("mdctlioctl(%s %lx %p %x %p)\n",
@@ -1195,6 +1196,16 @@ mdctlioctl(dev_t dev, u_long cmd, caddr_t addr, int flags, struct thread *td)
 			break;
 		}
 		return (0);
+	case MDIOCLIST:
+		i = 1;
+		LIST_FOREACH(sc, &md_softc_list, list) {
+			if (i == MDNPAD - 1)
+				mdio->md_pad[i] = -1;
+			else
+				mdio->md_pad[i++] = sc->unit;
+		}
+		mdio->md_pad[0] = i - 1;
+		return (0);
 	default:
 		return (ENOIOCTL);
 	};