On Thu, Mar 02, 2023 at 08:31:07AM +0100, Andreas Hindborg wrote: > > 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? It is userspace, code duplication isn't a big deal, but putting lots of un-related things together is just one mess. > > 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. I just suggest to make the userspace test code clean & easy, which plays big role for looking kernel interface from user side. > > > > >> > >> 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. No, please do not use __sector in this way, which is supposed to be used by driver for ZNS/ZONE_APPEND only. > > > > >> + > >> + 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 Short read should always be supported, so the interface may need to return how many zones in single command, please refer to nvme_ns_report_zones(). > considering overloading req->__data_len and iod->nr_sectors to convey > the number of requested zones. What do you think about that? Any field pre-suffixed with "__" in 'struct request' should be only for block layer, but __sector is one exception and its scenario is obvious. So please do not misuse req->__data_len, but using iod is fine. > > > > > 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_report_zones NULL > > > > >> }; > >> > >> #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? Here we should trust block core code. > > > > >> 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? It really depends on storage/zoned field knowledge. Thanks, Ming
