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 > > 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++) { > + 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); These are declarations, shouldn't they be dummy definitions instead? e.g. static int ublk_revalidate_disk_zones(struct gendisk *disk) { return -EOPNOTSUPP; }; It would be nice if they could be avoided altogether. Looking how e.g. null-blk and btrfs has solved this: https://github.com/torvalds/linux/blob/v6.2/fs/btrfs/Makefile#L39 https://github.com/torvalds/linux/blob/v6.2/drivers/block/null_blk/Makefile#L11 They have put the zoned stuff in a separate C file that is only compiled when CONFIG_BLK_DEV_ZONED is set. I'm not sure if a similar design is desired for ublk or not. However, if a similar design pattern was used, it could probably avoid some of these unpleasant dummy definitions altogether. Kind regards, Niklas > +#endif > +
