[RFC PATCH 2/4] block: add new flag to add partitions read-only

Daniel Golle
2022-11-17T00:43:39Z

Add flag ADDPART_FLAG_READONLY to allow partition parsers marking a
partition to be set read-only.
This is needed for the uImage.FIT partition parser added by a follow-up
commit: we need to be sure the contents of uImage.FIT sub-images
remain unaltered they are validated using a hash within the uImage.FIT
structure which also serves as partition table.

Signed-off-by: Daniel Golle <daniel@makrotopia.org>
---
block/blk.h | 1 +
block/partitions/core.c | 3 +++
2 files changed, 4 insertions(+)

diff --git a/block/blk.h b/block/blk.h
index e85703ae81dd..05ac426350b2 100644
--- a/block/blk.h
+++ b/block/blk.h
@@ -414,6 +414,7 @@ void blk_free_ext_minor(unsigned int minor);
#define ADDPART_FLAG_NONE 0
#define ADDPART_FLAG_RAID 1
#define ADDPART_FLAG_WHOLEDISK 2
+#define ADDPART_FLAG_READONLY 4
int bdev_add_partition(struct gendisk *disk, int partno, sector_t start,
sector_t length);
int bdev_del_partition(struct gendisk *disk, int partno);
diff --git a/block/partitions/core.c b/block/partitions/core.c
index b8112f52d388..355646b0707d 100644
--- a/block/partitions/core.c
+++ b/block/partitions/core.c
@@ -398,6 +398,9 @@ static struct block_device *add_partition(struct gendisk *disk, int partno,
goto out_del;
}

+ if (flags & ADDPART_FLAG_READONLY)
+ bdev->bd_read_only = true;
+
/* everything is up and running, commence */
err = xa_insert(&disk->part_tbl, partno, bdev, GFP_KERNEL);
if (err)
--
2.38.1