[PATCH v4 2/2] ubi: expose the volume CRC check skip flag

From: Quentin Schulz
Date: Mon Jul 02 2018 - 04:34:14 EST


Now that we have the logic for skipping CRC check for static UBI volumes
in the core, let's expose it to users.

This makes use of a padding byte in the volume description data
structure as a flag. This flag only tell for now whether we should skip
the CRC check of a volume.

This checks the UBI volume for which we are trying to skip the CRC check
is static.

Suggested-by: Boris Brezillon <boris.brezillon@xxxxxxxxxxx>
Signed-off-by: Quentin Schulz <quentin.schulz@xxxxxxxxxxx>
Reviewed-by: Boris Brezillon <boris.brezillon@xxxxxxxxxxx>
---
drivers/mtd/ubi/cdev.c | 7 +++++++
drivers/mtd/ubi/vmt.c | 3 +++
include/uapi/mtd/ubi-user.h | 18 ++++++++++++++++--
3 files changed, 26 insertions(+), 2 deletions(-)

diff --git a/drivers/mtd/ubi/cdev.c b/drivers/mtd/ubi/cdev.c
index 45c3296..6fe3fe9 100644
--- a/drivers/mtd/ubi/cdev.c
+++ b/drivers/mtd/ubi/cdev.c
@@ -622,6 +622,13 @@ static int verify_mkvol_req(const struct ubi_device *ubi,
req->vol_type != UBI_STATIC_VOLUME)
goto bad;

+ if (req->flags & ~UBI_VOL_VALID_FLGS)
+ goto bad;
+
+ if (req->flags & UBI_VOL_SKIP_CRC_CHECK_FLG &&
+ req->vol_type != UBI_STATIC_VOLUME)
+ goto bad;
+
if (req->alignment > ubi->leb_size)
goto bad;

diff --git a/drivers/mtd/ubi/vmt.c b/drivers/mtd/ubi/vmt.c
index e2606a4..729588b 100644
--- a/drivers/mtd/ubi/vmt.c
+++ b/drivers/mtd/ubi/vmt.c
@@ -174,6 +174,9 @@ int ubi_create_volume(struct ubi_device *ubi, struct ubi_mkvol_req *req)
vol->dev.class = &ubi_class;
vol->dev.groups = volume_dev_groups;

+ if (req->flags & UBI_VOL_SKIP_CRC_CHECK_FLG)
+ vol->skip_check = 1;
+
spin_lock(&ubi->volumes_lock);
if (vol_id == UBI_VOL_NUM_AUTO) {
/* Find unused volume ID */
diff --git a/include/uapi/mtd/ubi-user.h b/include/uapi/mtd/ubi-user.h
index 5b04a49..aad3b62 100644
--- a/include/uapi/mtd/ubi-user.h
+++ b/include/uapi/mtd/ubi-user.h
@@ -285,6 +285,20 @@ struct ubi_attach_req {
__s8 padding[10];
};

+/*
+ * UBI volume flags.
+ *
+ * @UBI_VOL_SKIP_CRC_CHECK_FLG: skip the CRC check done on a static volume at
+ * open time. Only valid for static volumes and
+ * should only be used if the volume user has a
+ * way to verify data integrity
+ */
+enum {
+ UBI_VOL_SKIP_CRC_CHECK_FLG = 0x1,
+};
+
+#define UBI_VOL_VALID_FLGS (UBI_VOL_SKIP_CRC_CHECK_FLG)
+
/**
* struct ubi_mkvol_req - volume description data structure used in
* volume creation requests.
@@ -292,7 +306,7 @@ struct ubi_attach_req {
* @alignment: volume alignment
* @bytes: volume size in bytes
* @vol_type: volume type (%UBI_DYNAMIC_VOLUME or %UBI_STATIC_VOLUME)
- * @padding1: reserved for future, not used, has to be zeroed
+ * @flags: volume flags (%UBI_VOL_SKIP_CRC_CHECK_FLG)
* @name_len: volume name length
* @padding2: reserved for future, not used, has to be zeroed
* @name: volume name
@@ -321,7 +335,7 @@ struct ubi_mkvol_req {
__s32 alignment;
__s64 bytes;
__s8 vol_type;
- __s8 padding1;
+ __u8 flags;
__s16 name_len;
__s8 padding2[4];
char name[UBI_MAX_VOLUME_NAME + 1];
--
git-series 0.9.1