[PATCH v7 3/3] ublk: enable zoned storage support

From: Andreas Hindborg
Date: Mon Jul 10 2023 - 02:46:38 EST

From: Andreas Hindborg <a.hindborg@xxxxxxxxxxx>

Add zoned storage support to ublk: report_zones and operations:
- REQ_OP_ZONE_OPEN
- REQ_OP_ZONE_CLOSE
- REQ_OP_ZONE_FINISH
- REQ_OP_ZONE_RESET
- REQ_OP_ZONE_APPEND

The zone append feature uses the `addr` field of `struct ublksrv_io_cmd` to
communicate ALBA back to the kernel. Therefore ublk must be used with the
user copy feature (UBLK_F_USER_COPY) for zoned storage support to be
available. Without this feature, ublk will not allow zoned storage support.

Signed-off-by: Andreas Hindborg <a.hindborg@xxxxxxxxxxx>
---
drivers/block/ublk_drv.c | 314 ++++++++++++++++++++++++++++++++--
include/uapi/linux/ublk_cmd.h | 30 ++++
2 files changed, 328 insertions(+), 16 deletions(-)

diff --git a/drivers/block/ublk_drv.c b/drivers/block/ublk_drv.c
index 8d271901efac..a57be961b708 100644
--- a/drivers/block/ublk_drv.c
+++ b/drivers/block/ublk_drv.c
@@ -56,16 +56,21 @@
| UBLK_F_USER_RECOVERY_REISSUE \
| UBLK_F_UNPRIVILEGED_DEV \
| UBLK_F_CMD_IOCTL_ENCODE \
- | UBLK_F_USER_COPY)
+ | UBLK_F_USER_COPY \
+ | UBLK_F_ZONED)

/* 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)
+#define UBLK_PARAM_TYPE_ALL \
+ (UBLK_PARAM_TYPE_BASIC | UBLK_PARAM_TYPE_DISCARD | \
+ UBLK_PARAM_TYPE_DEVT | UBLK_PARAM_TYPE_ZONED)

struct ublk_rq_data {
struct llist_node node;

struct kref ref;
+ __u64 sector;
+ __u32 operation;
+ __u32 nr_sectors;
};

struct ublk_uring_cmd_pdu {
@@ -110,6 +115,11 @@ struct ublk_uring_cmd_pdu {
*/
#define UBLK_IO_FLAG_NEED_GET_DATA 0x08

+/*
+ * Set when IO is Zone Append
+ */
+#define UBLK_IO_FLAG_ZONE_APPEND 0x10
+
struct ublk_io {
/* userspace buffer address from io cmd */
__u64 addr;
@@ -190,6 +200,198 @@ static inline bool ublk_dev_is_user_copy(const struct ublk_device *ub)
return ub->dev_info.flags & UBLK_F_USER_COPY;
}

+static inline bool ublk_dev_is_zoned(const struct ublk_device *ub)
+{
+ return ub->dev_info.flags & UBLK_F_ZONED;
+}
+
+static inline bool ublk_queue_is_zoned(struct ublk_queue *ubq)
+{
+ return ubq->flags & UBLK_F_ZONED;
+}
+
+#ifdef CONFIG_BLK_DEV_ZONED
+
+static int ublk_get_nr_zones(const struct ublk_device *ub)
+{
+ const struct ublk_param_basic *p = &ub->params.basic;
+
+ /* Zone size is a power of 2 */
+ return p->dev_sectors >> ilog2(p->chunk_sectors);
+}
+
+static int ublk_revalidate_disk_zones(struct ublk_device *ub)
+{
+ return blk_revalidate_disk_zones(ub->ub_disk, NULL);
+}
+
+static int ublk_dev_param_zoned_validate(const struct ublk_device *ub)
+{
+ const struct ublk_param_zoned *p = &ub->params.zoned;
+ int nr_zones;
+
+ if (!ublk_dev_is_zoned(ub))
+ return -EINVAL;
+
+ if (!p->max_zone_append_sectors)
+ return -EINVAL;
+
+ nr_zones = ublk_get_nr_zones(ub);
+
+ if (p->max_active_zones > nr_zones)
+ return -EINVAL;
+
+ if (p->max_open_zones > nr_zones)
+ return -EINVAL;
+
+ return 0;
+}
+
+static int ublk_dev_param_zoned_apply(struct ublk_device *ub)
+{
+ const struct ublk_param_zoned *p = &ub->params.zoned;
+
+ disk_set_zoned(ub->ub_disk, BLK_ZONED_HM);
+ blk_queue_required_elevator_features(ub->ub_disk->queue,
+ ELEVATOR_F_ZBD_SEQ_WRITE);
+ disk_set_max_active_zones(ub->ub_disk, p->max_active_zones);
+ disk_set_max_open_zones(ub->ub_disk, p->max_open_zones);
+ blk_queue_max_zone_append_sectors(ub->ub_disk->queue, p->max_zone_append_sectors);
+
+ ub->ub_disk->nr_zones = ublk_get_nr_zones(ub);
+
+ return 0;
+}
+
+/* Based on virtblk_alloc_report_buffer */
+static void *ublk_alloc_report_buffer(struct ublk_device *ublk,
+ unsigned int nr_zones, size_t *buflen)
+{
+ struct request_queue *q = ublk->ub_disk->queue;
+ size_t bufsize;
+ void *buf;
+
+ nr_zones = min_t(unsigned int, nr_zones,
+ ublk->ub_disk->nr_zones);
+
+ bufsize = nr_zones * sizeof(struct blk_zone);
+ bufsize =
+ min_t(size_t, bufsize, queue_max_hw_sectors(q) << SECTOR_SHIFT);
+ bufsize = min_t(size_t, bufsize, queue_max_segments(q) << PAGE_SHIFT);
+
+ while (bufsize >= sizeof(struct blk_zone)) {
+ buf = __vmalloc(bufsize, GFP_KERNEL | __GFP_NORETRY);
+ if (buf) {
+ *buflen = bufsize;
+ return buf;
+ }
+ bufsize >>= 1;
+ }
+
+ *buflen = 0;
+ return NULL;
+}
+
+static int ublk_report_zones(struct gendisk *disk, sector_t sector,
+ unsigned int nr_zones, report_zones_cb cb, void *data)
+{
+ struct ublk_device *ub = disk->private_data;
+ unsigned int zone_size_sectors = disk->queue->limits.chunk_sectors;
+ unsigned int first_zone = sector >> ilog2(zone_size_sectors);
+ unsigned int done_zones = 0;
+ unsigned int max_zones_per_request;
+ int ret;
+ struct blk_zone *buffer;
+ size_t buffer_length;
+
+ nr_zones = min_t(unsigned int, ub->ub_disk->nr_zones - first_zone,
+ nr_zones);
+
+ buffer = ublk_alloc_report_buffer(ub, nr_zones, &buffer_length);
+ if (!buffer)
+ return -ENOMEM;
+
+ max_zones_per_request = buffer_length / sizeof(struct blk_zone);
+
+ while (done_zones < nr_zones) {
+ unsigned int remaining_zones = nr_zones - done_zones;
+ unsigned int zones_in_request =
+ min_t(unsigned int, remaining_zones, max_zones_per_request);
+ struct request *req;
+ struct ublk_rq_data *pdu;
+ blk_status_t status;
+
+ memset(buffer, 0, buffer_length);
+
+ req = blk_mq_alloc_request(disk->queue, REQ_OP_DRV_IN, 0);
+ if (IS_ERR(req)) {
+ ret = PTR_ERR(req);
+ goto out;
+ }
+
+ pdu = blk_mq_rq_to_pdu(req);
+ pdu->operation = UBLK_IO_OP_REPORT_ZONES;
+ pdu->sector = sector;
+ pdu->nr_sectors = remaining_zones * zone_size_sectors;
+
+ ret = blk_rq_map_kern(disk->queue, req, buffer, buffer_length,
+ GFP_KERNEL);
+ if (ret) {
+ blk_mq_free_request(req);
+ goto out;
+ }
+
+ status = blk_execute_rq(req, 0);
+ ret = blk_status_to_errno(status);
+ blk_mq_free_request(req);
+ if (ret)
+ goto out;
+
+ for (unsigned int i = 0; i < zones_in_request; i++) {
+ struct blk_zone *zone = buffer + i;
+
+ /* A zero length zone means no more zones in this response */
+ if (!zone->len)
+ break;
+
+ ret = cb(zone, i, data);
+ if (ret)
+ goto out;
+
+ done_zones++;
+ sector += zone_size_sectors;
+
+ }
+ }
+
+ ret = done_zones;
+
+out:
+ kvfree(buffer);
+ return ret;
+}
+
+#else
+
+#define ublk_report_zones (NULL)
+
+static int ublk_dev_param_zoned_validate(const struct ublk_device *ub)
+{
+ return -EOPNOTSUPP;
+}
+
+static int ublk_dev_param_zoned_apply(struct ublk_device *ub)
+{
+ return -EOPNOTSUPP;
+}
+
+static int ublk_revalidate_disk_zones(struct ublk_device *ub)
+{
+ return 0;
+}
+
+#endif
+
static inline void __ublk_complete_rq(struct request *req);
static void ublk_complete_rq(struct kref *ref);

@@ -232,7 +434,7 @@ static inline unsigned ublk_pos_to_tag(loff_t pos)
UBLK_TAG_BITS_MASK;
}

-static void ublk_dev_param_basic_apply(struct ublk_device *ub)
+static int ublk_dev_param_basic_apply(struct ublk_device *ub)
{
struct request_queue *q = ub->ub_disk->queue;
const struct ublk_param_basic *p = &ub->params.basic;
@@ -257,6 +459,8 @@ 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);
+
+ return 0;
}

static void ublk_dev_param_discard_apply(struct ublk_device *ub)
@@ -286,6 +490,9 @@ static int ublk_validate_params(const struct ublk_device *ub)

if (p->max_sectors > (ub->dev_info.max_io_buf_bytes >> 9))
return -EINVAL;
+
+ if (ublk_dev_is_zoned(ub) && !p->chunk_sectors)
+ return -EINVAL;
} else
return -EINVAL;

@@ -304,19 +511,31 @@ static int ublk_validate_params(const struct ublk_device *ub)
if (ub->params.types & UBLK_PARAM_TYPE_DEVT)
return -EINVAL;

+ if (ub->params.types & UBLK_PARAM_TYPE_ZONED)
+ return ublk_dev_param_zoned_validate(ub);
+ else if (ublk_dev_is_zoned(ub))
+ return -EINVAL;
+
return 0;
}

static int ublk_apply_params(struct ublk_device *ub)
{
+ int ret;
+
if (!(ub->params.types & UBLK_PARAM_TYPE_BASIC))
return -EINVAL;

- ublk_dev_param_basic_apply(ub);
+ ret = ublk_dev_param_basic_apply(ub);
+ if (ret)
+ return ret;

if (ub->params.types & UBLK_PARAM_TYPE_DISCARD)
ublk_dev_param_discard_apply(ub);

+ if (ub->params.types & UBLK_PARAM_TYPE_ZONED)
+ return ublk_dev_param_zoned_apply(ub);
+
return 0;
}

@@ -487,6 +706,7 @@ static const struct block_device_operations ub_fops = {
.owner = THIS_MODULE,
.open = ublk_open,
.free_disk = ublk_free_disk,
+ .report_zones = ublk_report_zones,
};

#define UBLK_MAX_PIN_PAGES 32
@@ -601,7 +821,8 @@ static inline bool ublk_need_map_req(const struct request *req)

static inline bool ublk_need_unmap_req(const struct request *req)
{
- return ublk_rq_has_data(req) && req_op(req) == REQ_OP_READ;
+ return ublk_rq_has_data(req) &&
+ (req_op(req) == REQ_OP_READ || req_op(req) == REQ_OP_DRV_IN);
}

static int ublk_map_io(const struct ublk_queue *ubq, const struct request *req,
@@ -685,8 +906,14 @@ static blk_status_t ublk_setup_iod(struct ublk_queue *ubq, struct request *req)
{
struct ublksrv_io_desc *iod = ublk_get_iod(ubq, req->tag);
struct ublk_io *io = &ubq->ios[req->tag];
+ struct ublk_rq_data *pdu = blk_mq_rq_to_pdu(req);
+ enum req_op op = req_op(req);
u32 ublk_op;

+ if (!ublk_queue_is_zoned(ubq) &&
+ (op_is_zone_mgmt(op) || op == REQ_OP_ZONE_APPEND))
+ return -EIO;
+
switch (req_op(req)) {
case REQ_OP_READ:
ublk_op = UBLK_IO_OP_READ;
@@ -703,6 +930,37 @@ static blk_status_t ublk_setup_iod(struct ublk_queue *ubq, struct request *req)
case REQ_OP_WRITE_ZEROES:
ublk_op = UBLK_IO_OP_WRITE_ZEROES;
break;
+ case REQ_OP_ZONE_OPEN:
+ ublk_op = UBLK_IO_OP_ZONE_OPEN;
+ break;
+ case REQ_OP_ZONE_CLOSE:
+ ublk_op = UBLK_IO_OP_ZONE_CLOSE;
+ break;
+ case REQ_OP_ZONE_FINISH:
+ ublk_op = UBLK_IO_OP_ZONE_FINISH;
+ break;
+ case REQ_OP_ZONE_RESET:
+ ublk_op = UBLK_IO_OP_ZONE_RESET;
+ break;
+ case REQ_OP_DRV_IN:
+ ublk_op = pdu->operation;
+ switch (ublk_op) {
+ case UBLK_IO_OP_REPORT_ZONES:
+ iod->op_flags = ublk_op | ublk_req_build_flags(req);
+ iod->nr_sectors = pdu->nr_sectors;
+ iod->start_sector = pdu->sector;
+ return BLK_STS_OK;
+ default:
+ return BLK_STS_IOERR;
+ }
+ case REQ_OP_ZONE_APPEND:
+ ublk_op = UBLK_IO_OP_ZONE_APPEND;
+ io->flags |= UBLK_IO_FLAG_ZONE_APPEND;
+ break;
+ case REQ_OP_ZONE_RESET_ALL:
+ case REQ_OP_DRV_OUT:
+ /* We do not support reset_all and drv_out */
+ return BLK_STS_NOTSUPP;
default:
return BLK_STS_IOERR;
}
@@ -756,7 +1014,8 @@ static inline void __ublk_complete_rq(struct request *req)
*
* Both the two needn't unmap.
*/
- if (req_op(req) != REQ_OP_READ && req_op(req) != REQ_OP_WRITE)
+ if (req_op(req) != REQ_OP_READ && req_op(req) != REQ_OP_WRITE &&
+ req_op(req) != REQ_OP_DRV_IN)
goto exit;

/* for READ request, writing data in iod->addr to rq buffers */
@@ -1120,6 +1379,11 @@ static void ublk_commit_completion(struct ublk_device *ub,
/* find the io request and complete */
req = blk_mq_tag_to_rq(ub->tag_set.tags[qid], tag);

+ if (io->flags & UBLK_IO_FLAG_ZONE_APPEND) {
+ req->__sector = ub_cmd->addr;
+ io->flags &= ~UBLK_IO_FLAG_ZONE_APPEND;
+ }
+
if (req && likely(!blk_should_fake_timeout(req->q)))
ublk_put_req_ref(ubq, req);
}
@@ -1419,7 +1683,8 @@ static int __ublk_ch_uring_cmd(struct io_uring_cmd *cmd,
^ (_IOC_NR(cmd_op) == UBLK_IO_NEED_GET_DATA))
goto out;

- if (ublk_support_user_copy(ubq) && ub_cmd->addr) {
+ if (ublk_support_user_copy(ubq) &&
+ !(io->flags & UBLK_IO_FLAG_ZONE_APPEND) && ub_cmd->addr) {
ret = -EINVAL;
goto out;
}
@@ -1542,11 +1807,14 @@ static inline bool ublk_check_ubuf_dir(const struct request *req,
int ubuf_dir)
{
/* copy ubuf to request pages */
- if (req_op(req) == REQ_OP_READ && ubuf_dir == ITER_SOURCE)
+ if ((req_op(req) == REQ_OP_READ || req_op(req) == REQ_OP_DRV_IN) &&
+ ubuf_dir == ITER_SOURCE)
return true;

/* copy request pages to ubuf */
- if (req_op(req) == REQ_OP_WRITE && ubuf_dir == ITER_DEST)
+ if ((req_op(req) == REQ_OP_WRITE ||
+ req_op(req) == REQ_OP_ZONE_APPEND) &&
+ ubuf_dir == ITER_DEST)
return true;

return false;
@@ -1885,17 +2153,24 @@ static int ublk_ctrl_start_dev(struct ublk_device *ub, struct io_uring_cmd *cmd)

get_device(&ub->cdev_dev);
ub->dev_info.state = UBLK_S_DEV_LIVE;
+
+ if (ublk_dev_is_zoned(ub)) {
+ ret = ublk_revalidate_disk_zones(ub);
+ if (ret)
+ goto out_put_cdev;
+ }
+
ret = add_disk(disk);
+ if (ret)
+ goto out_put_cdev;
+
+ set_bit(UB_STATE_USED, &ub->state);
+
+out_put_cdev:
if (ret) {
- /*
- * Has to drop the reference since ->free_disk won't be
- * called in case of add_disk failure.
- */
ub->dev_info.state = UBLK_S_DEV_DEAD;
ublk_put_device(ub);
- goto out_put_disk;
}
- set_bit(UB_STATE_USED, &ub->state);
out_put_disk:
if (ret)
put_disk(disk);
@@ -2045,6 +2320,13 @@ static int ublk_ctrl_add_dev(struct io_uring_cmd *cmd)
if (ublk_dev_is_user_copy(ub))
ub->dev_info.flags &= ~UBLK_F_NEED_GET_DATA;

+ /* Zoned storage support requires user copy feature */
+ if (ublk_dev_is_zoned(ub) &&
+ (!IS_ENABLED(CONFIG_BLK_DEV_ZONED) || !ublk_dev_is_user_copy(ub))) {
+ ret = -EINVAL;
+ goto out_free_dev_number;
+ }
+
/* We are not ready to support zero copy */
ub->dev_info.flags &= ~UBLK_F_SUPPORT_ZERO_COPY;

diff --git a/include/uapi/linux/ublk_cmd.h b/include/uapi/linux/ublk_cmd.h
index 521a0d2fbc06..215c596efe3a 100644
--- a/include/uapi/linux/ublk_cmd.h
+++ b/include/uapi/linux/ublk_cmd.h
@@ -176,6 +176,12 @@
/* Copy between request and user buffer by pread()/pwrite() */
#define UBLK_F_USER_COPY (1UL << 7)

+/*
+ * User space sets this flag when setting up the device to request zoned storage support. Kernel may
+ * deny the request by returning an error.
+ */
+#define UBLK_F_ZONED (1ULL << 8)
+
/* device state */
#define UBLK_S_DEV_DEAD 0
#define UBLK_S_DEV_LIVE 1
@@ -235,6 +241,11 @@ struct ublksrv_ctrl_dev_info {
#define UBLK_IO_OP_DISCARD 3
#define UBLK_IO_OP_WRITE_SAME 4
#define UBLK_IO_OP_WRITE_ZEROES 5
+#define UBLK_IO_OP_ZONE_OPEN 10
+#define UBLK_IO_OP_ZONE_CLOSE 11
+#define UBLK_IO_OP_ZONE_FINISH 12
+#define UBLK_IO_OP_ZONE_APPEND 13
+#define UBLK_IO_OP_ZONE_RESET 15
/*
* Ublk passthrough operation code ranges, and each passthrough operation
* provides generic interface between ublk kernel driver and ublk userspace, and
@@ -243,6 +254,16 @@ struct ublksrv_ctrl_dev_info {
* ublk kernel driver has to be involved for handling this operation.
*/
#define __UBLK_IO_OP_DRV_IN_START 32
+/*
+ * Construct a zone report. The report request is carried in `struct
+ * ublksrv_io_desc`. The `start_sector` field must be the first sector of a zone
+ * and shall indicate the first zone of the report. The `nr_sectors` shall
+ * indicate how many zones should be reported (divide by zone size to get number
+ * of zones in the report) and must be an integer multiple of the zone size. The
+ * report shall be delivered as a `struct blk_zone` array. To report fewer zones
+ * than requested, zero the last entry of the returned array.
+ */
+#define UBLK_IO_OP_REPORT_ZONES __UBLK_IO_OP_DRV_IN_START
#define __UBLK_IO_OP_DRV_IN_END 96
#define __UBLK_IO_OP_DRV_OUT_START __UBLK_IO_OP_DRV_IN_END
#define __UBLK_IO_OP_DRV_OUT_END 160
@@ -342,6 +363,13 @@ struct ublk_param_devt {
__u32 disk_minor;
};

+struct ublk_param_zoned {
+ __u32 max_open_zones;
+ __u32 max_active_zones;
+ __u32 max_zone_append_sectors;
+ __u8 reserved[20];
+};
+
struct ublk_params {
/*
* Total length of parameters, userspace has to set 'len' for both
@@ -353,11 +381,13 @@ struct ublk_params {
#define UBLK_PARAM_TYPE_BASIC (1 << 0)
#define UBLK_PARAM_TYPE_DISCARD (1 << 1)
#define UBLK_PARAM_TYPE_DEVT (1 << 2)
+#define UBLK_PARAM_TYPE_ZONED (1 << 3)
__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;
};

#endif
--
2.41.0