On Wed, 27 Jun 2018 13:33:19 +0200
Quentin Schulz <quentin.sch...@bootlin.com> wrote:
> Some users of static UBI volumes implement their own integrity check,
> thus making the volume CRC check done at open time useless. For
> instance, this is the case when one use the ubiblock + dm-verity +
> squashfs combination, where dm-verity already checks integrity of the
> block device but this time at the block granularity instead of verifying
> the whole volume.
>
> Skipping this test drastically improves the boot-time.
>
> Suggested-by: Boris Brezillon <boris.brezil...@bootlin.com>
> Signed-off-by: Quentin Schulz <quentin.sch...@bootlin.com>
Just a few minor comments (see below).
Reviewed-by: Boris Brezillon <boris.brezil...@bootlin.com>
> ---
> drivers/mtd/ubi/kapi.c | 2 +-
> drivers/mtd/ubi/ubi-media.h | 6 ++++++
> drivers/mtd/ubi/ubi.h | 4 ++++
> drivers/mtd/ubi/vmt.c | 9 +++++++++
> drivers/mtd/ubi/vtbl.c | 3 +++
> 5 files changed, 23 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/mtd/ubi/kapi.c b/drivers/mtd/ubi/kapi.c
> index d4b2e87..e9e9ecb 100644
> --- a/drivers/mtd/ubi/kapi.c
> +++ b/drivers/mtd/ubi/kapi.c
> @@ -202,7 +202,7 @@ struct ubi_volume_desc *ubi_open_volume(int ubi_num, int
> vol_id, int mode)
> desc->mode = mode;
>
> mutex_lock(&ubi->ckvol_mutex);
> - if (!vol->checked) {
> + if (!vol->checked && !vol->skip_check) {
> /* This is the first open - check the volume */
> err = ubi_check_volume(ubi, vol_id);
> if (err < 0) {
> diff --git a/drivers/mtd/ubi/ubi-media.h b/drivers/mtd/ubi/ubi-media.h
> index 195ff8c..f43a4ff 100644
> --- a/drivers/mtd/ubi/ubi-media.h
> +++ b/drivers/mtd/ubi/ubi-media.h
> @@ -45,6 +45,11 @@ enum {
> * Volume flags used in the volume table record.
> *
> * @UBI_VTBL_AUTORESIZE_FLG: auto-resize this volume
> + * @UBI_VTBL_SKIP_CRC_CHECK_FLG: skip the CRC check done on static volume at
^ volumes?
> + * open time. Should only be set on volumes that
> + * are used by upper layers doing this kind of
> + * check. Main use-case for this flag is
> + * boot-time reduction
> *
> * %UBI_VTBL_AUTORESIZE_FLG flag can be set only for one volume in the volume
> * table. UBI automatically re-sizes the volume which has this flag and makes
> @@ -76,6 +81,7 @@ enum {
> */
> enum {
> UBI_VTBL_AUTORESIZE_FLG = 0x01,
> + UBI_VTBL_SKIP_CRC_CHECK_FLG = 0x02,
> };
>
> /*
> diff --git a/drivers/mtd/ubi/ubi.h b/drivers/mtd/ubi/ubi.h
> index f5ba97c..429102b 100644
> --- a/drivers/mtd/ubi/ubi.h
> +++ b/drivers/mtd/ubi/ubi.h
> @@ -327,6 +327,9 @@ struct ubi_eba_leb_desc {
> * atomic LEB change
> *
> * @eba_tbl: EBA table of this volume (LEB->PEB mapping)
> + * @skip_check: %1 if CRC check of static volumes should be skipped. Directly
> + * reflect the presence of the %UBI_VTBL_SKIP_CRC_CHECK_FLG in the
^ reflects? ^ %UBI_VTBL_SKIP_CRC_CHECK_FLG
*flag* in
> + * vtbl entry
> * @checked: %1 if this static volume was checked
> * @corrupted: %1 if the volume is corrupted (static volumes only)
> * @upd_marker: %1 if the update marker is set for this volume
> @@ -374,6 +377,7 @@ struct ubi_volume {
> void *upd_buf;
>
> struct ubi_eba_table *eba_tbl;
> + unsigned int skip_check:1;
> unsigned int checked:1;
> unsigned int corrupted:1;
> unsigned int upd_marker:1;
> diff --git a/drivers/mtd/ubi/vmt.c b/drivers/mtd/ubi/vmt.c
> index 0be5167..e2606a4 100644
> --- a/drivers/mtd/ubi/vmt.c
> +++ b/drivers/mtd/ubi/vmt.c
> @@ -299,6 +299,10 @@ int ubi_create_volume(struct ubi_device *ubi, struct
> ubi_mkvol_req *req)
> vtbl_rec.vol_type = UBI_VID_DYNAMIC;
> else
> vtbl_rec.vol_type = UBI_VID_STATIC;
> +
> + if (vol->skip_check)
> + vtbl_rec.flags |= UBI_VTBL_SKIP_CRC_CHECK_FLG;
> +
> memcpy(vtbl_rec.name, vol->name, vol->name_len);
>
> err = ubi_change_vtbl_record(ubi, vol_id, &vtbl_rec);
> @@ -733,6 +737,11 @@ static int self_check_volume(struct ubi_device *ubi, int
> vol_id)
> ubi_err(ubi, "bad used_bytes");
> goto fail;
> }
> +
> + if (vol->skip_check) {
> + ubi_err(ubi, "bad skip_check");
> + goto fail;
> + }
> } else {
> if (vol->used_ebs < 0 || vol->used_ebs > vol->reserved_pebs) {
> ubi_err(ubi, "bad used_ebs");
> diff --git a/drivers/mtd/ubi/vtbl.c b/drivers/mtd/ubi/vtbl.c
> index 94d7a86..2c133cd 100644
> --- a/drivers/mtd/ubi/vtbl.c
> +++ b/drivers/mtd/ubi/vtbl.c
> @@ -560,6 +560,9 @@ static int init_volumes(struct ubi_device *ubi,
> vol->name[vol->name_len] = '\0';
> vol->vol_id = i;
>
> + if (vtbl[i].flags & UBI_VTBL_SKIP_CRC_CHECK_FLG)
> + vol->skip_check = 1;
> +
> if (vtbl[i].flags & UBI_VTBL_AUTORESIZE_FLG) {
> /* Auto re-size flag may be set only for one volume */
> if (ubi->autoresize_vol_id != -1) {
