Re: [PATCH v4 3/4] ublk: enable zoned storage support
From: Andreas Hindborg (Samsung)
Date: Fri Jun 30 2023 - 12:54:23 EST
Ming Lei <ming.lei@xxxxxxxxxx> writes:
> On Wed, Jun 28, 2023 at 09:06:48PM +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
>>
>> Note: This commit changes the ublk kernel module name from `ublk_drv.ko` to
>> `ublk.ko` in order to link multiple translation units into the module.
>>
>> Signed-off-by: Andreas Hindborg <a.hindborg@xxxxxxxxxxx>
>> ---
>> MAINTAINERS | 1 +
>> drivers/block/Kconfig | 4 +
>> drivers/block/Makefile | 4 +-
>> drivers/block/ublk_drv-zoned.c | 144 +++++++++++++++++++++++++++++++++
>> drivers/block/ublk_drv.c | 64 +++++++++++++--
>> drivers/block/ublk_drv.h | 15 ++++
>> include/uapi/linux/ublk_cmd.h | 14 ++++
>> 7 files changed, 239 insertions(+), 7 deletions(-)
>> create mode 100644 drivers/block/ublk_drv-zoned.c
>>
>> diff --git a/MAINTAINERS b/MAINTAINERS
>> index ace71c90751c..db8a8deb5926 100644
>> --- a/MAINTAINERS
>> +++ b/MAINTAINERS
>> @@ -21555,6 +21555,7 @@ S: Maintained
>> F: Documentation/block/ublk.rst
>> F: drivers/block/ublk_drv.c
>> F: drivers/block/ublk_drv.h
>> +F: drivers/block/ublk_drv-zoned.c
>> F: include/uapi/linux/ublk_cmd.h
>>
>> UCLINUX (M68KNOMMU AND COLDFIRE)
>> diff --git a/drivers/block/Kconfig b/drivers/block/Kconfig
>> index 5b9d4aaebb81..c58dfd035557 100644
>> --- a/drivers/block/Kconfig
>> +++ b/drivers/block/Kconfig
>> @@ -402,6 +402,10 @@ config BLKDEV_UBLK_LEGACY_OPCODES
>> suggested to enable N if your application(ublk server) switches to
>> ioctl command encoding.
>>
>> +config BLK_DEV_UBLK_ZONED
>> + def_bool y
>> + depends on BLK_DEV_UBLK && BLK_DEV_ZONED
>> +
>> source "drivers/block/rnbd/Kconfig"
>>
>> endif # BLK_DEV
>> diff --git a/drivers/block/Makefile b/drivers/block/Makefile
>> index 101612cba303..bc1649e20ec2 100644
>> --- a/drivers/block/Makefile
>> +++ b/drivers/block/Makefile
>> @@ -37,6 +37,8 @@ obj-$(CONFIG_BLK_DEV_RNBD) += rnbd/
>>
>> obj-$(CONFIG_BLK_DEV_NULL_BLK) += null_blk/
>>
>> -obj-$(CONFIG_BLK_DEV_UBLK) += ublk_drv.o
>> +obj-$(CONFIG_BLK_DEV_UBLK) += ublk.o
>> +ublk-$(CONFIG_BLK_DEV_UBLK) += ublk_drv.o
>> +ublk-$(CONFIG_BLK_DEV_UBLK_ZONED) += ublk_drv-zoned.o
>>
>> swim_mod-y := swim.o swim_asm.o
>> diff --git a/drivers/block/ublk_drv-zoned.c b/drivers/block/ublk_drv-zoned.c
>> new file mode 100644
>> index 000000000000..ea86bf4b3681
>> --- /dev/null
>> +++ b/drivers/block/ublk_drv-zoned.c
>> @@ -0,0 +1,144 @@
>> +// SPDX-License-Identifier: GPL-2.0
>> +/*
>> + * Copyright 2023 Andreas Hindborg <a.hindborg@xxxxxxxxxxx>
>> + */
>> +#include <linux/blkzoned.h>
>> +#include <linux/ublk_cmd.h>
>> +#include <linux/vmalloc.h>
>> +
>> +#include "ublk_drv.h"
>> +
>> +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;
>> +}
>> +
>> +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);
>> + }
>> +}
>> +
>> +int ublk_revalidate_disk_zones(struct gendisk *disk)
>> +{
>> + return blk_revalidate_disk_zones(disk, NULL);
>> +}
>> +
>> +/* Based on virtblk_alloc_report_buffer */
>> +static void *ublk_alloc_report_buffer(struct ublk_device *ublk,
>> + unsigned int nr_zones,
>> + unsigned int zone_sectors, size_t *buflen)
>> +{
>> + struct request_queue *q = ublk->ub_disk->queue;
>> + size_t bufsize;
>> + void *buf;
>> +
>> + nr_zones = min_t(unsigned int, nr_zones,
>> + get_capacity(ublk->ub_disk) >> ilog2(zone_sectors));
>> +
>> + 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);
>
> This means 'blk_zone'(includes any sub-field type) is reused as part of ublk's UAPI,
> and it is smart, please document it around UBLK_IO_OP_REPORT_ZONES's definition.
Will do 👍
>
>> +
>> + while (bufsize >= sizeof(struct blk_zone)) {
>> + buf = __vmalloc(bufsize, GFP_KERNEL | __GFP_NORETRY);
>> + if (buf) {
>> + *buflen = bufsize;
>> + return buf;
>> + }
>> + bufsize >>= 1;
>> + }
>> +
>> + bufsize = 0;
>> + return NULL;
>> +}
>> +
>> +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;
>> + struct blk_zone *buffer;
>> + size_t buffer_length;
>> +
>> + if (!(ub->dev_info.flags & UBLK_F_ZONED))
>> + 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, zone_size_sectors,
>> + &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);
>> + int err = 0;
>> + 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))
>> + return PTR_ERR(req);
>> +
>> + 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;
>> +
>> + err = blk_rq_map_kern(disk->queue, req, buffer, buffer_length,
>> + GFP_KERNEL);
>> + if (err) {
>> + blk_mq_free_request(req);
>> + kvfree(buffer);
>> + return err;
>> + }
>> +
>> + status = blk_execute_rq(req, 0);
>> + err = blk_status_to_errno(status);
>> + blk_mq_free_request(req);
>> + if (err) {
>> + kvfree(buffer);
>> + return err;
>> + }
>> +
>> + for (unsigned int i = 0; i < zones_in_request; i++) {
>> + struct blk_zone *zone = buffer + i;
>> +
>> + err = cb(zone, i, data);
>> + if (err)
>> + return err;
>> +
>> + done_zones++;
>> + sector += zone_size_sectors;
>> +
>> + /* A zero length zone means don't ask for more zones */
>> + if (!zone->len) {
>
> This way is part of UAPI UBLK_IO_OP_REPORT_ZONES, please document it
> around UBLK_IO_OP_REPORT_ZONES.
OK 👍
>
>> + kvfree(buffer);
>> + return done_zones;
>> + }
>> + }
>> + }
>> +
>> + kvfree(buffer);
>> + return done_zones;
>> +}
>> diff --git a/drivers/block/ublk_drv.c b/drivers/block/ublk_drv.c
>> index e519dc0d9fe7..88fa39853c61 100644
>> --- a/drivers/block/ublk_drv.c
>> +++ b/drivers/block/ublk_drv.c
>> @@ -57,12 +57,13 @@
>> | 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_uring_cmd_pdu {
>> struct ublk_queue *ubq;
>> @@ -209,6 +210,9 @@ 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)
>> @@ -269,6 +273,9 @@ 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;
>> }
>>
>> @@ -439,6 +446,7 @@ 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
>> @@ -553,7 +561,8 @@ 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,
>> @@ -637,6 +646,7 @@ 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)) {
>> @@ -655,6 +665,35 @@ 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;
>> + iod->addr = io->addr;
>
> As Damien commented, zone append needs to be moved into this patch,
> so zoned depends on user copy feature, and you can simply fail to
> add device if user copy isn't enabled.
>
> So the above 'iod->addr = io->addr' can be removed.
Thanks 👍
>
>> + return BLK_STS_OK;
>> + default:
>> + return BLK_STS_IOERR;
>> + }
>> + case REQ_OP_ZONE_APPEND:
>> + case REQ_OP_ZONE_RESET_ALL:
>> + case REQ_OP_DRV_OUT:
>> + /* We do not support zone append or reset_all yet */
>> + fallthrough;
>> default:
>> return BLK_STS_IOERR;
>> }
>> @@ -708,7 +747,8 @@ 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 */
>> @@ -1835,6 +1875,15 @@ 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);
>>
>> + 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);
>> ub->dev_info.state = UBLK_S_DEV_LIVE;
>> ret = add_disk(disk);
>> @@ -1997,6 +2046,9 @@ static int ublk_ctrl_add_dev(struct io_uring_cmd *cmd)
>> if (ub->dev_info.flags & UBLK_F_USER_COPY)
>> ub->dev_info.flags &= ~UBLK_F_NEED_GET_DATA;
>>
>> + 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/drivers/block/ublk_drv.h b/drivers/block/ublk_drv.h
>> index f81e62256456..7242430fd6b9 100644
>> --- a/drivers/block/ublk_drv.h
>> +++ b/drivers/block/ublk_drv.h
>> @@ -50,6 +50,21 @@ struct ublk_rq_data {
>> struct llist_node node;
>>
>> struct kref ref;
>> + enum ublk_op operation;
>> + __u64 sector;
>> + __u32 nr_sectors;
>> };
>>
>> +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);
>> +
>> +#ifdef CONFIG_BLK_DEV_UBLK_ZONED
>> +int ublk_report_zones(struct gendisk *disk, sector_t sector,
>> + unsigned int nr_zones, report_zones_cb cb,
>> + void *data);
>> +#else
>> +#define ublk_report_zones NULL
>> +#endif
>> +
>> #endif
>> diff --git a/include/uapi/linux/ublk_cmd.h b/include/uapi/linux/ublk_cmd.h
>> index 471b3b983045..436525afffe8 100644
>> --- a/include/uapi/linux/ublk_cmd.h
>> +++ b/include/uapi/linux/ublk_cmd.h
>> @@ -176,6 +176,11 @@
>> /* Copy between request and user buffer by pread()/pwrite() */
>> #define UBLK_F_USER_COPY (1UL << 7)
>>
>> +/*
>> + * Enable zoned device support
>> + */
>> +#define UBLK_F_ZONED (1ULL << 8)
>> +
>> /* device state */
>> #define UBLK_S_DEV_DEAD 0
>> #define UBLK_S_DEV_LIVE 1
>> @@ -242,6 +247,7 @@ enum ublk_op {
>> UBLK_IO_OP_ZONE_APPEND = 13,
>> UBLK_IO_OP_ZONE_RESET = 15,
>> __UBLK_IO_OP_DRV_IN_START = 32,
>> + UBLK_IO_OP_REPORT_ZONES = __UBLK_IO_OP_DRV_IN_START,
>> __UBLK_IO_OP_DRV_IN_END = 96,
>> __UBLK_IO_OP_DRV_OUT_START = __UBLK_IO_OP_DRV_IN_END,
>> __UBLK_IO_OP_DRV_OUT_END = 160,
>> @@ -342,6 +348,12 @@ struct ublk_param_devt {
>> __u32 disk_minor;
>> };
>>
>> +struct ublk_param_zoned {
>> + __u32 max_open_zones;
>> + __u32 max_active_zones;
>> + __u8 reserved[24];
>> +};
>
> Maybe you can simply borrow virtio_blk_zoned_characteristics definition
> here, and make several reserved words.
>
> But that is fine, given six u32 should be flexible enough compared with
> virtio_blk_zoned_characteristics.
I agree, this should be enough. One field will go to max append size, so
20 bytes left.
Best regards,
Andreas