[PATCH 16/19] block: don't discover partition with DPS no-auto GPT attribute

[Vincent Mailhol]

DPS [1] defines GPT attribute bit 63 as no-auto. Partitions with this
bit set must not be used by automatic discovery.

Add the new GPT_ATTRIBUTE_NO_AUTO flag to designate the GPT attribute
bit 63.

Add the new ADDPART_FLAG_NO_AUTO flag and set it when
GPT_ATTRIBUTE_NO_AUTO is set during the partition scan. Then, propagate
it to the new BD_NO_AUTO_DISCOVERY flag.

Finally, add a condition to match_dev_by_type_uuid() to exclude any
partition with that flag from the automatic discovery.

[1] The Discoverable Partitions Specification (DPS)
Link: https://uapi-group.org/specifications/specs/discoverable_partitions_specification/

Signed-off-by: Vincent Mailhol <mailhol@xxxxxxxxxx>
---
 block/blk.h               | 1 +
 block/early-lookup.c      | 1 +
 block/partitions/core.c   | 2 ++
 block/partitions/efi.c    | 2 ++
 block/partitions/efi.h    | 3 +++
 include/linux/blk_types.h | 1 +
 6 files changed, 10 insertions(+)

diff --git a/block/blk.h b/block/blk.h
index b998a7761faf..14e0f349ff14 100644
--- a/block/blk.h
+++ b/block/blk.h
@@ -604,6 +604,7 @@ void blk_free_ext_minor(unsigned int minor);
 #define ADDPART_FLAG_RAID	1
 #define ADDPART_FLAG_WHOLEDISK	2
 #define ADDPART_FLAG_READONLY	4
+#define ADDPART_FLAG_NO_AUTO	8
 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/early-lookup.c b/block/early-lookup.c
index cd10785e70ac..8db0abec141e 100644
--- a/block/early-lookup.c
+++ b/block/early-lookup.c
@@ -266,6 +266,7 @@ static int __init match_dev_by_type_uuid(struct device *dev, const void *data)
 	const struct uuidcmp *cmp = data;
 
 	return bdev->bd_disk == cmp->disk && bdev->bd_meta_info &&
+	       !bdev_test_flag(bdev, BD_NO_AUTO_DISCOVERY) &&
 	       !strcasecmp(cmp->uuid, bdev->bd_meta_info->type_uuid);
 }
 
diff --git a/block/partitions/core.c b/block/partitions/core.c
index 5d5332ce586b..4529ea1d308e 100644
--- a/block/partitions/core.c
+++ b/block/partitions/core.c
@@ -382,6 +382,8 @@ static struct block_device *add_partition(struct gendisk *disk, int partno,
 
 	if (flags & ADDPART_FLAG_READONLY)
 		bdev_set_flag(bdev, BD_READ_ONLY);
+	if (flags & ADDPART_FLAG_NO_AUTO)
+		bdev_set_flag(bdev, BD_NO_AUTO_DISCOVERY);
 
 	/* everything is up and running, commence */
 	err = xa_insert(&disk->part_tbl, partno, bdev, GFP_KERNEL);
diff --git a/block/partitions/efi.c b/block/partitions/efi.c
index 4a3835ed9561..50c21625e256 100644
--- a/block/partitions/efi.c
+++ b/block/partitions/efi.c
@@ -739,6 +739,8 @@ int efi_partition(struct parsed_partitions *state)
 		/* If this is a RAID volume, tell md */
 		if (!efi_guidcmp(ptes[i].partition_type_guid, PARTITION_LINUX_RAID_GUID))
 			state->parts[i + 1].flags = ADDPART_FLAG_RAID;
+		if (le64_to_cpu(ptes[i].attributes) & GPT_ATTRIBUTE_NO_AUTO)
+			state->parts[i + 1].flags |= ADDPART_FLAG_NO_AUTO;
 
 		info = &state->parts[i + 1].info;
 		efi_guid_to_str(&ptes[i].unique_partition_guid, info->uuid);
diff --git a/block/partitions/efi.h b/block/partitions/efi.h
index 1f56f93b2804..fb50edb66e84 100644
--- a/block/partitions/efi.h
+++ b/block/partitions/efi.h
@@ -11,6 +11,7 @@
 #ifndef FS_PART_EFI_H_INCLUDED
 #define FS_PART_EFI_H_INCLUDED
 
+#include <linux/bits.h>
 #include <linux/types.h>
 #include <linux/fs.h>
 #include <linux/kernel.h>
@@ -30,6 +31,8 @@
 #define GPT_HEADER_REVISION_V1 0x00010000
 #define GPT_PRIMARY_PARTITION_TABLE_LBA 1
 
+#define GPT_ATTRIBUTE_NO_AUTO BIT_U64(63)
+
 #define PARTITION_SYSTEM_GUID \
     EFI_GUID( 0xC12A7328, 0xF81F, 0x11d2, \
               0xBA, 0x4B, 0x00, 0xA0, 0xC9, 0x3E, 0xC9, 0x3B) 
diff --git a/include/linux/blk_types.h b/include/linux/blk_types.h
index 8808ee76e73c..c6cdc99b0490 100644
--- a/include/linux/blk_types.h
+++ b/include/linux/blk_types.h
@@ -54,6 +54,7 @@ struct block_device {
 #ifdef CONFIG_FAIL_MAKE_REQUEST
 #define BD_MAKE_IT_FAIL		(1u<<12)
 #endif
+#define BD_NO_AUTO_DISCOVERY	(1u<<13)
 	dev_t			bd_dev;
 	struct address_space	*bd_mapping;	/* page cache */
 

-- 
2.53.0