Re: [PATCH v6 3/3] ublk: enable zoned storage support
From: Andreas Hindborg (Samsung)
Date: Sat Jul 08 2023 - 06:04:54 EST
Ming Lei <ming.lei@xxxxxxxxxx> writes:
> On Thu, Jul 06, 2023 at 03:09:30PM +0200, Andreas Hindborg wrote:
>> 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/Kconfig | 4 +
>> drivers/block/ublk_drv.c | 341 ++++++++++++++++++++++++++++++++--
>> include/uapi/linux/ublk_cmd.h | 30 +++
>> 3 files changed, 363 insertions(+), 12 deletions(-)
>>
>> diff --git a/drivers/block/Kconfig b/drivers/block/Kconfig
>> index 5b9d4aaebb81..3f7bedae8511 100644
>> --- a/drivers/block/Kconfig
>> +++ b/drivers/block/Kconfig
>> @@ -373,6 +373,7 @@ config BLK_DEV_RBD
>> config BLK_DEV_UBLK
>> tristate "Userspace block driver (Experimental)"
>> select IO_URING
>> + select BLK_DEV_UBLK_ZONED if BLK_DEV_ZONED
>> help
>> io_uring based userspace block driver. Together with ublk server, ublk
>> has been working well, but interface with userspace or command data
>> @@ -402,6 +403,9 @@ config BLKDEV_UBLK_LEGACY_OPCODES
>> suggested to enable N if your application(ublk server) switches to
>> ioctl command encoding.
>>
>> +config BLK_DEV_UBLK_ZONED
>> + bool
>> +
>> source "drivers/block/rnbd/Kconfig"
>>
>> endif # BLK_DEV
>> diff --git a/drivers/block/ublk_drv.c b/drivers/block/ublk_drv.c
>> index 8d271901efac..a5adcfc976a5 100644
>> --- a/drivers/block/ublk_drv.c
>> +++ b/drivers/block/ublk_drv.c
>> @@ -56,22 +56,28 @@
>> | 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;
>> + __u32 operation;
>> + __u64 sector;
>> + __u32 nr_sectors;
>> };
>
> Please put "operation" and "nr_sectors" together, then holes
> can be avoided.
Got it 👍
>
>>
>> struct ublk_uring_cmd_pdu {
>> struct ublk_queue *ubq;
>> };
>>
>> +
>
> ?
Sorry.
>
>> /*
>> * io command is active: sqe cmd is received, and its cqe isn't done
>> *
>> @@ -110,6 +116,11 @@ 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;
>> @@ -184,6 +195,31 @@ struct ublk_params_header {
>> __u32 len;
>> __u32 types;
>> };
>> +static inline int ublk_dev_params_zoned(const struct ublk_device *ub)
>> +{
>> + return ub->params.types & UBLK_PARAM_TYPE_ZONED;
>> +}
>> +
>> +static inline bool ublk_dev_is_zoned(const struct ublk_device *ub)
>> +{
>> + return ub->dev_info.flags & UBLK_F_ZONED;
>> +}
>> +
>> +static int ublk_set_nr_zones(struct ublk_device *ub);
>> +static int ublk_dev_param_zoned_validate(const struct ublk_device *ub);
>> +static int ublk_dev_param_zoned_apply(struct ublk_device *ub);
>> +static int ublk_revalidate_disk_zones(struct ublk_device *ub);
>> +
>> +#ifndef CONFIG_BLK_DEV_UBLK_ZONED
>> +
>> +#define ublk_report_zones (NULL)
>> +
>> +#else
>> +
>> +static int ublk_report_zones(struct gendisk *disk, sector_t sector,
>> + unsigned int nr_zones, report_zones_cb cb, void *data);
>> +
>> +#endif
>
> Please merge the following "#ifdef CONFIG_BLK_DEV_UBLK_ZONED" with the
> above one, then you can avoid the above declarations. Meantime, we don't
> add code after MODULE_LICENSE().
Ok 👍
>
>>
>> static inline bool ublk_dev_is_user_copy(const struct ublk_device *ub)
>> {
>> @@ -232,7 +268,7 @@ 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 +293,11 @@ 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 (ublk_dev_is_zoned(ub))
>> + return ublk_set_nr_zones(ub);
>> +
>
> The above change can be moved into ublk_dev_param_zoned_apply() which
> is always done after ublk_dev_param_basic_apply().
Ok
>
>> + return 0;
>> }
>>
>> static void ublk_dev_param_discard_apply(struct ublk_device *ub)
>> @@ -286,6 +327,9 @@ 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 +348,26 @@ static int ublk_validate_params(const struct ublk_device *ub)
>> if (ub->params.types & UBLK_PARAM_TYPE_DEVT)
>> return -EINVAL;
>>
>> - return 0;
>> + return ublk_dev_param_zoned_validate(ub);
>
> Please follow current style of:
>
> if (ub->params.types & UBLK_PARAM_TYPE_ZONED)
> return ublk_dev_param_zoned_validate(ub);
>
> Then you can avoid lots of check on ublk_dev_params_zoned().
Ok, but then I need
if (ublk_dev_is_zoned(ub) && !ublk_dev_params_zoned(ub))
return -EINVAL;
here to check if user is forgetting zoned parameters for zoned ublk dev.
Or do you want to drop this check?
>
>> }
>>
>> 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 (ublk_dev_params_zoned(ub))
>> + return ublk_dev_param_zoned_apply(ub);
>> +
>> return 0;
>> }
>>
>> @@ -487,6 +538,7 @@ 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 +653,8 @@ 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,
>> @@ -685,6 +738,7 @@ 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);
>> u32 ublk_op;
>>
>> switch (req_op(req)) {
>> @@ -703,6 +757,37 @@ 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:
>
> BLK_STS_NOTSUPP should be returned, since in future we may support it,
> and userspace need to know what is wrong.
Ok
>
>> + case REQ_OP_DRV_OUT:
>> + /* We do not support reset_all and drv_out */
>> + fallthrough;
>> default:
>> return BLK_STS_IOERR;
>> }
>> @@ -756,7 +841,8 @@ 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 +1206,11 @@ 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 +1510,8 @@ 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 +1634,14 @@ 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;
>> @@ -1883,8 +1978,12 @@ static int ublk_ctrl_start_dev(struct ublk_device *ub, struct io_uring_cmd *cmd)
>> if (ub->nr_privileged_daemon != ub->nr_queues_ready)
>> set_bit(GD_SUPPRESS_PART_SCAN, &disk->state);
>>
>> - get_device(&ub->cdev_dev);
>> ub->dev_info.state = UBLK_S_DEV_LIVE;
>> + ret = ublk_revalidate_disk_zones(ub);
>> + if (ret)
>> + goto out_put_disk;
>> +
>> + get_device(&ub->cdev_dev);
>> ret = add_disk(disk);
>> if (ret) {
>> /*
>> @@ -2045,6 +2144,13 @@ 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_UBLK_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;
>>
>> @@ -2629,3 +2735,214 @@ MODULE_PARM_DESC(ublks_max, "max number of ublk devices allowed to add(default:
>>
>> MODULE_AUTHOR("Ming Lei <ming.lei@xxxxxxxxxx>");
>> MODULE_LICENSE("GPL");
>> +
>> +#ifdef CONFIG_BLK_DEV_UBLK_ZONED
>> +
>> +static int get_nr_zones(const struct ublk_device *ub)
>> +{
>> + const struct ublk_param_basic *p = &ub->params.basic;
>> +
>> + if (!p->chunk_sectors)
>> + return 0;
>
> There isn't zoned device if the above check fails, so no
> need to check it.
Ok, but this is called from `ublk_dev_param_zoned_validate()` to
validate user sets params correct. Should we not report error to user
space during parameter validation if user space sets chunk_sectors to
zero for zoned device?
>
>> +
>> + /* Zone size is a power of 2 */
>> + return p->dev_sectors >> ilog2(p->chunk_sectors);
>> +}
>> +
>> +static int ublk_set_nr_zones(struct ublk_device *ub)
>> +{
>> + ub->ub_disk->nr_zones = get_nr_zones(ub);
>> + if (!ub->ub_disk->nr_zones)
>> + return -EINVAL;
>
> Is nr_zones one must for zoned?
Zero zones for a zoned storage device is not allowed, as far as I am
aware. Am I mistaken?
>
>> +
>> + return 0;
>> +}
>> +
>> +static int ublk_revalidate_disk_zones(struct ublk_device *ub)
>> +{
>> + if (ublk_dev_is_zoned(ub))
>> + return blk_revalidate_disk_zones(ub->ub_disk, NULL);
>> +
>> + return 0;
>> +}
>> +
>> +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) && !ublk_dev_params_zoned(ub))
>> + return -EINVAL;
>> +
>> + if (!ublk_dev_is_zoned(ub) && ublk_dev_params_zoned(ub))
>> + return -EINVAL;
>> +
>> + if (!ublk_dev_params_zoned(ub))
>> + return 0;
>
> The above can be simplified as single check if we follow current
> validate/apply code style:
>
> if (!ublk_dev_is_zoned(ub))
> return -EINVAL;
If we do that we will not be able to check if user space sets the
`UBLK_F_ZONED` flag without setting zoned parameters. Should I validate
that at call site or drop the check?
>> +
>> + if (!p->max_zone_append_sectors)
>> + return -EINVAL;
>> +
>> + nr_zones = 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);
>> +
>> + 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;
>> +
>> + if (!ublk_dev_is_zoned(ub))
>> + return -EOPNOTSUPP;
>> +
>> + 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
>> +
>> +static int ublk_set_nr_zones(struct ublk_device *ub)
>> +{
>> + return 0;
>> +}
>> +
>> +static int ublk_dev_param_zoned_validate(const struct ublk_device *ub)
>> +{
>> + if (ublk_dev_params_zoned(ub))
>> + return -EINVAL;
>> + return 0;
>
> Please move the check outside by following current code style, then:
>
> return -EINVAL;
>
Ok, but then we move the check for user applying zoned params to
non-zoned device when CONFIG_BLK_DEV_ZONED to call site?
>> +}
>> +
>> +static int ublk_dev_param_zoned_apply(struct ublk_device *ub)
>> +{
>> + if (ublk_dev_params_zoned(ub))
>> + return -EINVAL;
>> + return 0;
>
> It is enough to change
>
> return -EINVAL;
>
> directly.
Ok
Best regards,
Andreas