This allows implementation of zoned storage devices in user space. An
example user space implementation based on ubdsrv is available [1].

[1] https://github.com/metaspace/ubdsrv/commit/14a2b708f74f70cfecb076d92e680dc718cc1f6d

Signed-off-by: Andreas Hindborg <redacted>
---
Changes since v1:
 - Fixed conditional compilation bug
 - Refactored to collect conditional code additions together
 - Fixed style errors
 - Zero stack allocated value used for zone report

Reported-by: Niklas Cassel <redacted>
Reported-by: kernel test robot <redacted>
Link: https://lore.kernel.org/oe-kbuild-all/202302250222.XOrw9j6z-lkp@intel.com/ (local)
v1: https://lore.kernel.org/linux-block/20230224125950.214779-1-nmi@metaspace.dk/ (local)

 drivers/block/ublk_drv.c      | 150 ++++++++++++++++++++++++++++++++--
 include/uapi/linux/ublk_cmd.h |  18 ++++
 2 files changed, 162 insertions(+), 6 deletions(-)

diff --git a/drivers/block/ublk_drv.c b/drivers/block/ublk_drv.c
index 6368b56eacf1..37e516903867 100644
--- a/drivers/block/ublk_drv.c
+++ b/drivers/block/ublk_drv.c

@@ -20,6 +20,7 @@
 #include <linux/major.h>
 #include <linux/wait.h>
 #include <linux/blkdev.h>
+#include <linux/blkzoned.h>
 #include <linux/init.h>
 #include <linux/swap.h>
 #include <linux/slab.h>

@@ -51,10 +52,12 @@
                | UBLK_F_URING_CMD_COMP_IN_TASK \
                | UBLK_F_NEED_GET_DATA \
                | UBLK_F_USER_RECOVERY \
-               | UBLK_F_USER_RECOVERY_REISSUE)
+               | UBLK_F_USER_RECOVERY_REISSUE \
+               | UBLK_F_ZONED)

 /* All UBLK_PARAM_TYPE_* should be included here */
-#define UBLK_PARAM_TYPE_ALL (UBLK_PARAM_TYPE_BASIC | UBLK_PARAM_TYPE_DISCARD)
+#define UBLK_PARAM_TYPE_ALL (UBLK_PARAM_TYPE_BASIC | UBLK_PARAM_TYPE_DISCARD \
+                            | UBLK_PARAM_TYPE_ZONED)

 struct ublk_rq_data {
        struct llist_node node;

@@ -187,6 +190,98 @@ static DEFINE_MUTEX(ublk_ctl_mutex);

 static struct miscdevice ublk_misc;

+#ifdef CONFIG_BLK_DEV_ZONED
+static void ublk_set_nr_zones(struct ublk_device *ub)
+{
+       const struct ublk_param_basic *p = &ub->params.basic;
+
+       if (ub->dev_info.flags & UBLK_F_ZONED && p->chunk_sectors)
+               ub->ub_disk->nr_zones = p->dev_sectors / p->chunk_sectors;
+}
+
+static void ublk_dev_param_zoned_apply(struct ublk_device *ub)
+{
+       const struct ublk_param_zoned *p = &ub->params.zoned;
+
+       if (ub->dev_info.flags & UBLK_F_ZONED) {
+               disk_set_max_active_zones(ub->ub_disk, p->max_active_zones);
+               disk_set_max_open_zones(ub->ub_disk, p->max_open_zones);
+       }
+}
+
+static int ublk_revalidate_disk_zones(struct gendisk *disk)
+{
+       return blk_revalidate_disk_zones(disk, 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;
+       unsigned int zone_size;
+       unsigned int first_zone;
+       int ret = 0;
+
+       ub = disk->private_data;
+
+       if (!(ub->dev_info.flags & UBLK_F_ZONED))
+               return -EINVAL;
+
+       zone_size = disk->queue->limits.chunk_sectors;
+       first_zone = sector >> ilog2(zone_size);
+       nr_zones = min(ub->ub_disk->nr_zones - first_zone, nr_zones);
+
+       for (unsigned int i = 0; i < nr_zones; i++) {
+               struct request *req;
+               blk_status_t status;
+               struct blk_zone info = {0};
+
+               req = blk_mq_alloc_request(disk->queue, REQ_OP_DRV_IN, 0);
+
+               if (IS_ERR(req)) {
+                       ret = PTR_ERR(req);
+                       goto out;
+               }
+
+               req->__sector = sector;
+
+               ret = blk_rq_map_kern(disk->queue, req, &info, sizeof(info),
+                                     GFP_KERNEL);
+
+               if (ret)
+                       goto out;
+
+               status = blk_execute_rq(req, 0);

+               ret = blk_status_to_errno(status);
+               if (ret)
+                       goto out;
+
+               blk_mq_free_request(req);
+
+               ret = cb(&info, i, data);
+               if (ret)
+                       goto out;
+
+               /* A zero length zone means don't ask for more zones */
+               if (!info.len) {
+                       nr_zones = i;
+                       break;
+               }
+
+               sector += zone_size;
+       }
+       ret = nr_zones;
+
+ out:
+       return ret;
+}
+#else
+void ublk_set_nr_zones(struct ublk_device *ub);
+void ublk_dev_param_zoned_apply(struct ublk_device *ub);
+int ublk_revalidate_disk_zones(struct gendisk *disk);
+#endif
+
 static void ublk_dev_param_basic_apply(struct ublk_device *ub)
 {
        struct request_queue *q = ub->ub_disk->queue;

@@ -212,6 +307,9 @@ 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);
+
+       if (IS_ENABLED(CONFIG_BLK_DEV_ZONED))
+               ublk_set_nr_zones(ub);
 }

 static void ublk_dev_param_discard_apply(struct ublk_device *ub)

@@ -268,6 +366,9 @@ static int ublk_apply_params(struct ublk_device *ub)
        if (ub->params.types & UBLK_PARAM_TYPE_DISCARD)
                ublk_dev_param_discard_apply(ub);

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

@@ -361,9 +462,13 @@ static void ublk_free_disk(struct gendisk *disk)
        put_device(&ub->cdev_dev);
 }

+
 static const struct block_device_operations ub_fops = {
-       .owner =        THIS_MODULE,
-       .free_disk =    ublk_free_disk,
+       .owner = THIS_MODULE,
+       .free_disk = ublk_free_disk,
+#ifdef CONFIG_BLK_DEV_ZONED
+       .report_zones = ublk_report_zones,
+#endif
 };

 #define UBLK_MAX_PIN_PAGES     32

@@ -499,7 +604,7 @@ static int ublk_unmap_io(const struct ublk_queue *ubq,
 {
        const unsigned int rq_bytes = blk_rq_bytes(req);

-       if (req_op(req) == REQ_OP_READ && ublk_rq_has_data(req)) {
+       if ((req_op(req) == REQ_OP_READ || req_op(req) == REQ_OP_DRV_IN) && ublk_rq_has_data(req)) {
                struct ublk_map_data data = {
                        .ubq    =       ubq,
                        .rq     =       req,

@@ -566,6 +671,26 @@ 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;
+#ifdef CONFIG_BLK_DEV_ZONED
+       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 = UBLK_IO_OP_DRV_IN;
+               break;
+       case REQ_OP_ZONE_APPEND:
+               /* We do not support zone append yet */
+               fallthrough;
+#endif
        default:
                return BLK_STS_IOERR;
        }

@@ -612,7 +737,8 @@ static 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) {
                blk_mq_end_request(req, BLK_STS_OK);
                return;
        }

@@ -1535,6 +1661,15 @@ static int ublk_ctrl_start_dev(struct io_uring_cmd *cmd)
        if (ret)
                goto out_put_disk;

+       if (IS_ENABLED(CONFIG_BLK_DEV_ZONED) &&
+           ub->dev_info.flags & UBLK_F_ZONED) {
+               disk_set_zoned(disk, BLK_ZONED_HM);
+               blk_queue_required_elevator_features(disk->queue, ELEVATOR_F_ZBD_SEQ_WRITE);
+               ret = ublk_revalidate_disk_zones(disk);
+               if (ret)
+                       goto out_put_disk;
+       }
+
        get_device(&ub->cdev_dev);
        ret = add_disk(disk);
        if (ret) {

@@ -1673,6 +1808,9 @@ static int ublk_ctrl_add_dev(struct io_uring_cmd *cmd)
        if (!IS_BUILTIN(CONFIG_BLK_DEV_UBLK))
                ub->dev_info.flags |= UBLK_F_URING_CMD_COMP_IN_TASK;

+       if (!IS_ENABLED(CONFIG_BLK_DEV_ZONED))
+               ub->dev_info.flags &= ~UBLK_F_ZONED;
+
        /* 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 8f88e3a29998..074b97821575 100644
--- a/include/uapi/linux/ublk_cmd.h
+++ b/include/uapi/linux/ublk_cmd.h

@@ -78,6 +78,10 @@
 #define UBLK_F_USER_RECOVERY   (1UL << 3)

 #define UBLK_F_USER_RECOVERY_REISSUE   (1UL << 4)
+/*
+ * Enable zoned device support
+ */
+#define UBLK_F_ZONED (1ULL << 5)

 /* device state */
 #define UBLK_S_DEV_DEAD        0

@@ -129,6 +133,12 @@ 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
+#define                UBLK_IO_OP_DRV_IN               34

 #define                UBLK_IO_F_FAILFAST_DEV          (1U << 8)
 #define                UBLK_IO_F_FAILFAST_TRANSPORT    (1U << 9)

@@ -214,6 +224,12 @@ struct ublk_param_discard {
        __u16   reserved0;
 };

+struct ublk_param_zoned {
+       __u64   max_open_zones;
+       __u64   max_active_zones;
+       __u64   max_append_size;
+};
+
 struct ublk_params {
        /*
         * Total length of parameters, userspace has to set 'len' for both

@@ -224,10 +240,12 @@ struct ublk_params {
        __u32   len;
 #define UBLK_PARAM_TYPE_BASIC           (1 << 0)
 #define UBLK_PARAM_TYPE_DISCARD         (1 << 1)
+#define UBLK_PARAM_TYPE_ZONED           (1 << 2)
        __u32   types;                  /* types of parameter included */

        struct ublk_param_basic         basic;
        struct ublk_param_discard       discard;
+       struct ublk_param_zoned         zoned;
 };

 #endif

base-commit: c9c3395d5e3dcc6daee66c6908354d47bf98cb0c
--
2.39.2