ublk: support UBLK_PARAM_TYPE_INTEGRITY in device creation

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.

[csander: drop redundant pi_tuple_size field, use block metadata UAPI
 constants, add param validation]

Signed-off-by: Stanley Zhang <stazhang@purestorage.com>
Signed-off-by: Caleb Sander Mateos <csander@purestorage.com>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

2 files changed, 119 insertions, 1 deletions

diff --git a/drivers/block/ublk_drv.c b/drivers/block/ublk_drv.c
index 53df4bfa2c92..a4d62e8e4f6b 100644
--- a/drivers/block/ublk_drv.c
+++ b/drivers/block/ublk_drv.c
@@ -44,6 +44,8 @@
 #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)
@@ -83,7 +85,8 @@
 #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 {
 	/*
@@ -301,6 +304,11 @@ static inline bool ublk_queue_is_zoned(const struct ublk_queue *ubq)
 	return ubq->flags & UBLK_F_ZONED;
 }
 
+static inline bool ublk_dev_support_integrity(const struct ublk_device *ub)
+{
+	return ub->dev_info.flags & UBLK_F_INTEGRITY;
+}
+
 #ifdef CONFIG_BLK_DEV_ZONED
 
 struct ublk_zoned_report_desc {
@@ -616,6 +624,53 @@ static void ublk_dev_param_basic_apply(struct ublk_device *ub)
 	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 */
@@ -678,6 +733,29 @@ static int ublk_validate_params(const struct ublk_device *ub)
 			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 (!ublk_dev_support_integrity(ub))
+			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;
 }
 
@@ -2950,6 +3028,23 @@ static int ublk_ctrl_start_dev(struct ublk_device *ub,
 		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.max_integrity_segments =
+			p->max_integrity_segments ?: USHRT_MAX;
+		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;
 
@@ -3140,6 +3235,10 @@ static int ublk_ctrl_add_dev(const struct ublksrv_ctrl_cmd *header)
 			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);
 
diff --git a/include/uapi/linux/ublk_cmd.h b/include/uapi/linux/ublk_cmd.h
index ec77dabba45b..4c141d7e4710 100644
--- a/include/uapi/linux/ublk_cmd.h
+++ b/include/uapi/linux/ublk_cmd.h
@@ -311,6 +311,12 @@
  */
 #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
@@ -600,6 +606,17 @@ struct ublk_param_segment {
 	__u8	pad[2];
 };
 
+struct ublk_param_integrity {
+	__u32	flags; /* LBMD_PI_CAP_* from linux/fs.h */
+	__u16	max_integrity_segments; /* 0 means no limit */
+	__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[5];
+};
+
 struct ublk_params {
 	/*
 	 * Total length of parameters, userspace has to set 'len' for both
@@ -614,6 +631,7 @@ struct ublk_params {
 #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;
@@ -622,6 +640,7 @@ struct ublk_params {
 	struct ublk_param_zoned	zoned;
 	struct ublk_param_dma_align	dma;
 	struct ublk_param_segment	seg;
+	struct ublk_param_integrity	integrity;
 };
 
 #endif