ide: move ide_remove_port_from_hwgroup() to ide-probe.c

Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
diff --git a/drivers/ide/ide-probe.c b/drivers/ide/ide-probe.c
index fdf00cd..21cdd9c 100644
--- a/drivers/ide/ide-probe.c
+++ b/drivers/ide/ide-probe.c
@@ -992,6 +992,41 @@
 	mutex_unlock(&ide_cfg_mtx);
 }
 
+void ide_remove_port_from_hwgroup(ide_hwif_t *hwif)
+{
+	ide_hwgroup_t *hwgroup = hwif->hwgroup;
+
+	spin_lock_irq(&ide_lock);
+	/*
+	 * Remove us from the hwgroup, and free
+	 * the hwgroup if we were the only member
+	 */
+	if (hwif->next == hwif) {
+		BUG_ON(hwgroup->hwif != hwif);
+		kfree(hwgroup);
+	} else {
+		/* There is another interface in hwgroup.
+		 * Unlink us, and set hwgroup->drive and ->hwif to
+		 * something sane.
+		 */
+		ide_hwif_t *g = hwgroup->hwif;
+
+		while (g->next != hwif)
+			g = g->next;
+		g->next = hwif->next;
+		if (hwgroup->hwif == hwif) {
+			/* Chose a random hwif for hwgroup->hwif.
+			 * It's guaranteed that there are no drives
+			 * left in the hwgroup.
+			 */
+			BUG_ON(hwgroup->drive != NULL);
+			hwgroup->hwif = g;
+		}
+		BUG_ON(hwgroup->hwif == hwif);
+	}
+	spin_unlock_irq(&ide_lock);
+}
+
 /*
  * This routine sets up the irq for an ide interface, and creates a new
  * hwgroup for the irq/hwif if none was previously assigned.