On Tue, Jan 06, 2026 at 08:32:08AM -0800, Caleb Sander Mateos wrote: > On Tue, Jan 6, 2026 at 5:09 AM Ming Lei <[email protected]> wrote: > > > > On Mon, Jan 05, 2026 at 05:57:35PM -0700, Caleb Sander Mateos wrote: > > > From: Stanley Zhang <[email protected]> > > > > > > Add a feature flag UBLK_F_INTEGRITY for a ublk server to request > > > integrity/metadata support when creating a ublk device. The ublk server > > > can also check for the feature flag on the created device or the result > > > of UBLK_U_CMD_GET_FEATURES to tell if the ublk driver supports it. > > > UBLK_F_INTEGRITY requires UBLK_F_USER_COPY, as user copy is the only > > > data copy mode initially supported for integrity data. > > > Add UBLK_PARAM_TYPE_INTEGRITY and struct ublk_param_integrity to struct > > > ublk_params to specify the integrity params of a ublk device. > > > UBLK_PARAM_TYPE_INTEGRITY requires UBLK_F_INTEGRITY and a nonzero > > > metadata_size. The LBMD_PI_CAP_* and LBMD_PI_CSUM_* values from the > > > linux/fs.h UAPI header are used for the flags and csum_type fields. > > > If the UBLK_PARAM_TYPE_INTEGRITY flag is set, validate the integrity > > > parameters and apply them to the blk_integrity limits. > > > The struct ublk_param_integrity validations are based on the checks in > > > blk_validate_integrity_limits(). Any invalid parameters should be > > > rejected before being applied to struct blk_integrity. > > > > > > Signed-off-by: Stanley Zhang <[email protected]> > > > [csander: drop redundant pi_tuple_size field, use block metadata UAPI > > > constants, add param validation] > > > Signed-off-by: Caleb Sander Mateos <[email protected]> > > > --- > > > drivers/block/ublk_drv.c | 94 ++++++++++++++++++++++++++++++++++- > > > include/uapi/linux/ublk_cmd.h | 18 +++++++ > > > 2 files changed, 111 insertions(+), 1 deletion(-) > > > > > > diff --git a/drivers/block/ublk_drv.c b/drivers/block/ublk_drv.c > > > index 8e3da9b2b93a..066c6ae062a0 100644 > > > --- a/drivers/block/ublk_drv.c > > > +++ b/drivers/block/ublk_drv.c > > > @@ -42,10 +42,12 @@ > > > #include <linux/mm.h> > > > #include <asm/page.h> > > > #include <linux/task_work.h> > > > #include <linux/namei.h> > > > #include <linux/kref.h> > > > +#include <linux/blk-integrity.h> > > > +#include <uapi/linux/fs.h> > > > #include <uapi/linux/ublk_cmd.h> > > > > > > #define UBLK_MINORS (1U << MINORBITS) > > > > > > #define UBLK_INVALID_BUF_IDX ((u16)-1) > > > @@ -81,11 +83,12 @@ > > > > > > /* All UBLK_PARAM_TYPE_* should be included here */ > > > #define UBLK_PARAM_TYPE_ALL \ > > > (UBLK_PARAM_TYPE_BASIC | UBLK_PARAM_TYPE_DISCARD | \ > > > UBLK_PARAM_TYPE_DEVT | UBLK_PARAM_TYPE_ZONED | \ > > > - UBLK_PARAM_TYPE_DMA_ALIGN | UBLK_PARAM_TYPE_SEGMENT) > > > + UBLK_PARAM_TYPE_DMA_ALIGN | UBLK_PARAM_TYPE_SEGMENT | \ > > > + UBLK_PARAM_TYPE_INTEGRITY) > > > > > > struct ublk_uring_cmd_pdu { > > > /* > > > * Store requests in same batch temporarily for queuing them to > > > * daemon context. > > > @@ -628,10 +631,57 @@ static void ublk_dev_param_basic_apply(struct > > > ublk_device *ub) > > > set_disk_ro(ub->ub_disk, true); > > > > > > set_capacity(ub->ub_disk, p->dev_sectors); > > > } > > > > > > +static int ublk_integrity_flags(u32 flags) > > > +{ > > > + int ret_flags = 0; > > > + > > > + if (flags & LBMD_PI_CAP_INTEGRITY) { > > > + flags &= ~LBMD_PI_CAP_INTEGRITY; > > > + ret_flags |= BLK_INTEGRITY_DEVICE_CAPABLE; > > > + } > > > + if (flags & LBMD_PI_CAP_REFTAG) { > > > + flags &= ~LBMD_PI_CAP_REFTAG; > > > + ret_flags |= BLK_INTEGRITY_REF_TAG; > > > + } > > > + return flags ? -EINVAL : ret_flags; > > > +} > > > + > > > +static int ublk_integrity_pi_tuple_size(u8 csum_type) > > > +{ > > > + switch (csum_type) { > > > + case LBMD_PI_CSUM_NONE: > > > + return 0; > > > + case LBMD_PI_CSUM_IP: > > > + case LBMD_PI_CSUM_CRC16_T10DIF: > > > + return 8; > > > + case LBMD_PI_CSUM_CRC64_NVME: > > > + return 16; > > > + default: > > > + return -EINVAL; > > > + } > > > +} > > > + > > > +static enum blk_integrity_checksum ublk_integrity_csum_type(u8 csum_type) > > > +{ > > > + switch (csum_type) { > > > + case LBMD_PI_CSUM_NONE: > > > + return BLK_INTEGRITY_CSUM_NONE; > > > + case LBMD_PI_CSUM_IP: > > > + return BLK_INTEGRITY_CSUM_IP; > > > + case LBMD_PI_CSUM_CRC16_T10DIF: > > > + return BLK_INTEGRITY_CSUM_CRC; > > > + case LBMD_PI_CSUM_CRC64_NVME: > > > + return BLK_INTEGRITY_CSUM_CRC64; > > > + default: > > > + WARN_ON_ONCE(1); > > > + return BLK_INTEGRITY_CSUM_NONE; > > > + } > > > +} > > > + > > > static int ublk_validate_params(const struct ublk_device *ub) > > > { > > > /* basic param is the only one which must be set */ > > > if (ub->params.types & UBLK_PARAM_TYPE_BASIC) { > > > const struct ublk_param_basic *p = &ub->params.basic; > > > @@ -690,10 +740,33 @@ static int ublk_validate_params(const struct > > > ublk_device *ub) > > > return -EINVAL; > > > if (p->max_segment_size < UBLK_MIN_SEGMENT_SIZE) > > > return -EINVAL; > > > } > > > > > > + if (ub->params.types & UBLK_PARAM_TYPE_INTEGRITY) { > > > + const struct ublk_param_integrity *p = > > > &ub->params.integrity; > > > + int pi_tuple_size = > > > ublk_integrity_pi_tuple_size(p->csum_type); > > > + int flags = ublk_integrity_flags(p->flags); > > > + > > > + if (!(ub->dev_info.flags & UBLK_F_INTEGRITY)) > > > + return -EINVAL; > > > + if (flags < 0) > > > + return flags; > > > + if (pi_tuple_size < 0) > > > + return pi_tuple_size; > > > + if (!p->metadata_size) > > > + return -EINVAL; > > > + if (p->csum_type == LBMD_PI_CSUM_NONE && > > > + p->flags & LBMD_PI_CAP_REFTAG) > > > + return -EINVAL; > > > + if (p->pi_offset + pi_tuple_size > p->metadata_size) > > > + return -EINVAL; > > > + if (p->interval_exp < SECTOR_SHIFT || > > > + p->interval_exp > ub->params.basic.logical_bs_shift) > > > + return -EINVAL; > > > + } > > > + > > > return 0; > > > } > > > > > > static void ublk_apply_params(struct ublk_device *ub) > > > { > > > @@ -2941,10 +3014,25 @@ static int ublk_ctrl_start_dev(struct ublk_device > > > *ub, > > > lim.seg_boundary_mask = ub->params.seg.seg_boundary_mask; > > > lim.max_segment_size = ub->params.seg.max_segment_size; > > > lim.max_segments = ub->params.seg.max_segments; > > > } > > > > > > + if (ub->params.types & UBLK_PARAM_TYPE_INTEGRITY) { > > > + const struct ublk_param_integrity *p = > > > &ub->params.integrity; > > > + int pi_tuple_size = > > > ublk_integrity_pi_tuple_size(p->csum_type); > > > + > > > + lim.integrity = (struct blk_integrity) { > > > + .flags = ublk_integrity_flags(p->flags), > > > + .csum_type = ublk_integrity_csum_type(p->csum_type), > > > + .metadata_size = p->metadata_size, > > > + .pi_offset = p->pi_offset, > > > + .interval_exp = p->interval_exp, > > > + .tag_size = p->tag_size, > > > + .pi_tuple_size = pi_tuple_size, > > > + }; > > > + } > > > + > > > if (wait_for_completion_interruptible(&ub->completion) != 0) > > > return -EINTR; > > > > > > if (ub->ublksrv_tgid != ublksrv_pid) > > > return -EINVAL; > > > @@ -3131,10 +3219,14 @@ static int ublk_ctrl_add_dev(const struct > > > ublksrv_ctrl_cmd *header) > > > if (info.flags & (UBLK_F_USER_COPY | > > > UBLK_F_SUPPORT_ZERO_COPY | > > > UBLK_F_AUTO_BUF_REG)) > > > return -EINVAL; > > > } > > > > > > + /* User copy is required to access integrity buffer */ > > > + if (info.flags & UBLK_F_INTEGRITY && !(info.flags & > > > UBLK_F_USER_COPY)) > > > + return -EINVAL; > > > + > > > /* the created device is always owned by current user */ > > > ublk_store_owner_uid_gid(&info.owner_uid, &info.owner_gid); > > > > > > if (header->dev_id != info.dev_id) { > > > pr_warn("%s: dev id not match %u %u\n", > > > diff --git a/include/uapi/linux/ublk_cmd.h b/include/uapi/linux/ublk_cmd.h > > > index ec77dabba45b..a54c47832fa2 100644 > > > --- a/include/uapi/linux/ublk_cmd.h > > > +++ b/include/uapi/linux/ublk_cmd.h > > > @@ -309,10 +309,16 @@ > > > * the I/O's daemon task. The q_id and tag of the registered buffer are > > > required > > > * in UBLK_U_IO_UNREGISTER_IO_BUF's ublksrv_io_cmd. > > > */ > > > #define UBLK_F_BUF_REG_OFF_DAEMON (1ULL << 14) > > > > > > +/* > > > + * ublk device supports requests with integrity/metadata buffer. > > > + * Requires UBLK_F_USER_COPY. > > > + */ > > > +#define UBLK_F_INTEGRITY (1ULL << 16) > > > + > > > /* device state */ > > > #define UBLK_S_DEV_DEAD 0 > > > #define UBLK_S_DEV_LIVE 1 > > > #define UBLK_S_DEV_QUIESCED 2 > > > #define UBLK_S_DEV_FAIL_IO 3 > > > @@ -598,10 +604,20 @@ struct ublk_param_segment { > > > __u32 max_segment_size; > > > __u16 max_segments; > > > __u8 pad[2]; > > > }; > > > > > > +struct ublk_param_integrity { > > > + __u32 flags; /* LBMD_PI_CAP_* from linux/fs.h */ > > > + __u8 interval_exp; > > > + __u8 metadata_size; /* UBLK_PARAM_TYPE_INTEGRITY requires > > > nonzero */ > > > + __u8 pi_offset; > > > + __u8 csum_type; /* LBMD_PI_CSUM_* from linux/fs.h */ > > > + __u8 tag_size; > > > + __u8 pad[7]; > > > +}; > > > > Looks max_integrity_segments is missed, otherwise this patch is fine for me. > > My thinking was that there isn't any reason why a ublk server would > need to limit the number of integrity segments. The request integrity > segments aren't directly exposed to the ublk server through user copy. > And since zero copy isn't supported for integrity data, there's no > concern about needing to align the ublk integrity limits with the > backing device limits. What do you think?
Yeah, it isn't needed in current implementation, but things may change in future. How about adding it(__u16) to `ublk_param_integrity`? And document it is ignored for user-copy based implementation. It is usually part of HW/SW interface wrt. PI. Thanks, Ming
