On Fri, Jan 02, 2026 at 05:45:14PM -0700, Caleb Sander Mateos wrote:
> Indicate to the ublk server when an incoming request has integrity data
> by setting UBLK_IO_F_INTEGRITY in the ublksrv_io_desc's op_flags field.
> If the ublk device doesn't support integrity, the request will never
> provide integrity data. If the ublk device supports integrity, the
> request may omit the integrity buffer only if metadata_size matches the
> PI tuple size determined by csum_type. In this case, the ublk server
> should internally generate/verify the protection information from the
> data and sector offset.
> Set the UBLK_IO_F_CHECK_{GUARD,REFTAG,APPTAG} flags based on the
> request's BIP_CHECK_{GUARD,REFTAG,APPTAG} flags, indicating whether to
> verify the guard, reference, and app tags in the protection information.
> The expected reference tag (32 or 48 bits) and app tag (16 bits) are
> indicated in ublksrv_io_desc's new struct ublksrv_io_integrity integrity
> field. This field is unioned with the addr field to avoid changing theIt might be fine to set per-rq app_tag, but bios in one request might have different app_tag in case of io merge actually. Also block layer builds ref_tag for each internal, please see t10_pi_generate() and ext_pi_crc64_generate(). So looks this way is wrong. More importantly reusing iod->addr for other purpose not related with IO buffer is very unfriendly for adding new features, and one lesson is for ZONED support by reusing ublksrv_io_cmd->addr for zoned's append lba. For example, there is chance to support dma-buf based zero copy for ublk, and please see the io-uring dma-buf support[1], and iod->addr might carry IO buffer info in dma-buf format in future. [1] https://lore.kernel.org/io-uring/[email protected]/#t > size of struct ublksrv_io_desc. UBLK_F_INTEGRITY requires > UBLK_F_USER_COPY and the addr field isn't used for UBLK_F_USER_COPY, so > the two fields aren't needed simultaneously. > > Signed-off-by: Caleb Sander Mateos <[email protected]> > --- > drivers/block/ublk_drv.c | 43 +++++++++++++++++++++++++++++++---- > include/uapi/linux/ublk_cmd.h | 27 ++++++++++++++++++++-- > 2 files changed, 64 insertions(+), 6 deletions(-) > > diff --git a/drivers/block/ublk_drv.c b/drivers/block/ublk_drv.c > index 2f9316febf83..51469e0627ff 100644 > --- a/drivers/block/ublk_drv.c > +++ b/drivers/block/ublk_drv.c > @@ -316,10 +316,36 @@ static inline bool ublk_dev_is_zoned(const struct > ublk_device *ub) > static inline bool ublk_queue_is_zoned(const struct ublk_queue *ubq) > { > return ubq->flags & UBLK_F_ZONED; > } > > +static void ublk_setup_iod_buf(const struct ublk_queue *ubq, > + const struct request *req, > + struct ublksrv_io_desc *iod) > +{ > +#ifdef CONFIG_BLK_DEV_INTEGRITY > + if (ubq->flags & UBLK_F_INTEGRITY) { > + struct bio_integrity_payload *bip; > + sector_t ref_tag_seed; > + > + if (!blk_integrity_rq(req)) > + return; > + > + bip = bio_integrity(req->bio); > + ref_tag_seed = bip_get_seed(bip); As mentioned, t10_pi_generate() and ext_pi_crc64_generate() builds per-internal ref tag. > + iod->integrity.ref_tag_lo = ref_tag_seed; > + iod->integrity.ref_tag_hi = ref_tag_seed >> 32; > + iod->integrity.app_tag = bip->app_tag; In case of io merge, each bio may have different ->app_tag. Given you have to copy meta data via user copy, I suggest to follow the PI standard and make it per-internal. Thanks, Ming
