[PATCH] block: cmdline-parser: add support for hidden disk space

[Shawn Lin <shawn.lin@rock-chips.com>]

cmdline-partition now only support continuous disk space taken from
cmdline. When we need to reserve a disk space, for instance, 100m between
mmcblk0p1 and mmcblk0p2 for special use and wouldn't let kernel space
realize this "disk hole", we add this patch to ship adding this kind of
"disk hole" into the partition table. For any such cases, simply append
"hidden" to the end of subpart which is need to be reserved.

Signed-off-by: Shawn Lin <shawn.lin@rock-chips.com>
---

 block/cmdline-parser.c         | 12 +++++++++++-
 include/linux/cmdline-parser.h |  1 +
 2 files changed, 12 insertions(+), 1 deletion(-)

diff --git a/block/cmdline-parser.c b/block/cmdline-parser.c
index 9dbc67e..feecbcc 100644
--- a/block/cmdline-parser.c
+++ b/block/cmdline-parser.c
@@ -68,6 +68,11 @@ static int parse_subpart(struct cmdline_subpart **subpart, char *partdef)
 		partdef += 2;
 	}
 
+	if (!strncmp(partdef, "hidden", 6)) {
+		new_subpart->flags |= PF_HIDDEN;
+		partdef += 6;
+	}
+
 	*subpart = new_subpart;
 	return 0;
 fail:
@@ -128,7 +133,9 @@ static int parse_parts(struct cmdline_parts **parts, const char *bdevdef)
 		if (ret)
 			goto fail;
 
-		newparts->nr_subparts++;
+		if (!(subpart->flags & PF_HIDDEN))
+			newparts->nr_subparts++;
+
 		next_subpart = &(*next_subpart)->next_subpart;
 	}
 
@@ -245,6 +252,9 @@ int cmdline_parts_set(struct cmdline_parts *parts, sector_t disk_size,
 
 		from += subpart->size;
 
+		if (subpart->flags & PF_HIDDEN)
+			continue;
+
 		if (add_part(slot, subpart, param))
 			break;
 	}
diff --git a/include/linux/cmdline-parser.h b/include/linux/cmdline-parser.h
index 2e6dce6..7c1cb3c 100644
--- a/include/linux/cmdline-parser.h
+++ b/include/linux/cmdline-parser.h
@@ -14,6 +14,7 @@
 /* partition flags */
 #define PF_RDONLY                   0x01 /* Device is read only */
 #define PF_POWERUP_LOCK             0x02 /* Always locked after reset */
+#define PF_HIDDEN                   0x04 /* Hidden from partition table */
 
 struct cmdline_subpart {
 	char name[BDEVNAME_SIZE]; /* partition name, such as 'rootfs' */
-- 
2.3.7