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..2f9316febf83 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];
+};
+
 struct ublk_params {
        /*
         * Total length of parameters, userspace has to set 'len' for both
         * SET_PARAMS and GET_PARAMS command, and driver may update len
         * if two sides use different version of 'ublk_params', same with
@@ -612,16 +628,18 @@ struct ublk_params {
 #define UBLK_PARAM_TYPE_DISCARD         (1 << 1)
 #define UBLK_PARAM_TYPE_DEVT            (1 << 2)
 #define UBLK_PARAM_TYPE_ZONED           (1 << 3)
 #define UBLK_PARAM_TYPE_DMA_ALIGN       (1 << 4)
 #define UBLK_PARAM_TYPE_SEGMENT         (1 << 5)
+#define UBLK_PARAM_TYPE_INTEGRITY       (1 << 6) /* requires UBLK_F_INTEGRITY 
*/
        __u32   types;                  /* types of parameter included */
 
        struct ublk_param_basic         basic;
        struct ublk_param_discard       discard;
        struct ublk_param_devt          devt;
        struct ublk_param_zoned zoned;
        struct ublk_param_dma_align     dma;
        struct ublk_param_segment       seg;
+       struct ublk_param_integrity     integrity;
 };
 
 #endif
-- 
2.45.2


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