Hi Ming, Ming Lei <ming.lei@xxxxxxxxxx> writes: > On Fri, Feb 24, 2023 at 09:05:01PM +0100, Andreas Hindborg wrote: >> 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 >> >> 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 > > As I suggested, please write one simple & clean zoned target for verifying > the interface, and better to not add to tgt_null.c. For ubdsrv, I understand that you prefer to reimplement null and loop targets for zoned storage. I don't understand why you think this is a good idea, since we will have massive code duplication. This would be comparable to having a separate null_blk driver for zoned storage. Am I understanding you correctly? Anyway, I think we can discuss the kernel patch even though the ubdsrv implementation is not a separate target yet? The code would be almost identical, it would just live in a separate translation unit. > >> >> Signed-off-by: Andreas Hindborg <a.hindborg@xxxxxxxxxxx> >> --- >> 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 <Niklas.Cassel@xxxxxxx> >> Reported-by: kernel test robot <lkp@xxxxxxxxx> >> Link: https://lore.kernel.org/oe-kbuild-all/202302250222.XOrw9j6z-lkp@xxxxxxxxx/ >> v1: https://lore.kernel.org/linux-block/20230224125950.214779-1-nmi@xxxxxxxxxxxx/ >> >> 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++) { > > The local variable 'i' needs to be declared in the front part > of this function body. Ok. > >> + 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; > > Why is req->__sector set? I use it to carry information about the first zone of the report request. > >> + >> + 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; >> + } > > I'd suggest to report as many as possible zones in one command, and > the dev_info.max_io_buf_bytes is the max allowed buffer size for one > command, please refer to nvme_ns_report_zones(). I agree about fetching more zones. However, it is no good to fetch up to a max, since the requested zone report may less than max. I was considering overloading req->__data_len and iod->nr_sectors to convey the number of requested zones. What do you think about that? > > Also we are going to extend ublk in the multiple LUN/NS style, and I > guess that won't be one issue since ->report_zones() is always done on > disk level, right? Yes, that should be fine. > >> + 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 one null ublk_report_zones in #else branch of the above #ifdef, then we > can save one #ifdef. I would have to define it as a null pointer in the #else case then? > >> }; >> >> #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 > > The above '#ifdef' is needn't, since OP_ZONE should be defined no > matter if CONFIG_BLK_DEV_ZONED is enabled or not. I see. But do we want to process the requests if BLK_DEV_ZONED is not enabled, or do we want to fail the IO? > >> 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; >> +}; > > Is the above zoned parameter enough for future extension? > Does ZNS need extra parameter? Or some zoned new(important) features? @Damien, @Hans, @Matias, what do you think? > > I highly suggest to reserve some fields for extension, given > it is one ABI interface, which is supposed to be defined well > enough from the beginning. How many bytes would you reserve? Thanks! Best regards, Andreas
