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From:   "Andreas Hindborg (Samsung)" <nmi@metaspace.dk>
To:     aravind.ramesh@opensource.wdc.com
Cc:     Hans.Holmberg@wdc.com, Aravind.Ramesh@wdc.com, axboe@kernel.dk,
        linux-block@vger.kernel.org, hch@infradead.org,
        Matias.Bjorling@wdc.com, linux-kernel@vger.kernel.org,
        dlemoal@kernel.org, gost.dev@samsung.com, minwoo.im.dev@gmail.com,
        ming.lei@redhat.com
Subject: Re: [PATCH v4 3/4] ublk: enable zoned storage support
Date:   Fri, 30 Jun 2023 18:37:33 +0200
In-reply-to: <623b588e451bb41785375cc0711114c8@opensource.wdc.com>
Message-ID: <87y1k0dhme.fsf@metaspace.dk>
MIME-Version: 1.0
Content-Type: text/plain
Precedence: bulk


aravind.ramesh@opensource.wdc.com writes:

>> From: Andreas Hindborg <a.hindborg@samsung.com
>> <mailto:a.hindborg@samsung.com>>
>> 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@samsung.com
>> <mailto:a.hindborg@samsung.com>>
>> ---
>> 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
>
> nitpick: checkpatch.pl gives a warning on the ordering of the files.
> WARNING: Misordered MAINTAINERS entry - list file patterns in alphabetic order
>
>> 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@samsung.com
>> <mailto:a.hindborg@samsung.com>>
>> + */
>> +#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);
>> +
>> + 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) {
>> + 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;
>> + 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];
>> +};
>> +
>> struct ublk_params {
>> /*
>> * Total length of parameters, userspace has to set 'len' for both
>> @@ -353,11 +365,13 @@ struct ublk_params {
>> #define UBLK_PARAM_TYPE_BASIC (1 << 0)
>> #define UBLK_PARAM_TYPE_DISCARD (1 << 1)
>> #define UBLK_PARAM_TYPE_DEVT (1 << 2)
>> +#define UBLK_PARAM_TYPE_ZONED (1 << 3)
>> __u32 types; /* types of parameter included */
>> struct ublk_param_basic basic;
>> struct ublk_param_discard discard;
>> struct ublk_param_devt devt;
>> + struct ublk_param_zoned zoned;
>> };
>> #endif
> I applied the patches and verified it compiles with and without the
> CONFIG_BLK_DEV_ZONED flag.
> Working on creating a ublk device also.

For reference, here are my test scripts:


------------------------------------
test-append.sh:

#!/bin/bash
set -e
set -x

/mnt/nullblk.py
./ublk add -x --usercopy -t loop -f /dev/nullblk -q 8 -d 128
mkzonefs -f /dev/ublkb0
mount -t zonefs /dev/ublkb0 /zone
fio /mnt/append.fio
umount /zone
./ublk del 0


------------------------------------
nullblk.py:

#!/usr/bin/env python3

from subprocess import run
from pathlib import Path

block_size_bytes = 4096
zone_size_mib = 1024
num_zones = 32

config_path = Path("/sys/kernel/config/nullb")

# Remove all devices
for node in config_path.iterdir():
    if node.is_dir():
        node.rmdir()


device_capacity_mib = zone_size_mib * num_zones

control = config_path / "nullblk"
control.mkdir()

(control / "blocksize").write_text(str(block_size_bytes))
(control / "completion_nsec").write_text("0")
(control / "irqmode").write_text("0")
(control / "queue_mode").write_text("2")
(control / "hw_queue_depth").write_text("1024")
(control / "memory_backed").write_text("1")
(control / "size").write_text(str(device_capacity_mib))

(control / "zoned").write_text("1")
(control / "zone_size").write_text(str(zone_size_mib))
(control / "zone_nr_conv").write_text("0")
(control / "zone_max_active").write_text("14")
(control / "zone_max_open").write_text("14")

(control / "power").write_text("1")

------------------------------------

append.fio:

[global]
ioengine=psync
do_verify=1
verify=md5
random_generator=lfsr

[append0]
file_append=1
rw=write
bs=4k
direct=1
size=1024m
filename=/zone/seq/0

[append1]
file_append=1
rw=write
bs=4k
direct=1
size=1024m
filename=/zone/seq/1

[append2]
file_append=1
rw=write
bs=4k
direct=1
size=1024m
filename=/zone/seq/2

[append3]
file_append=1
rw=write
bs=4k
direct=1
size=1024m
filename=/zone/seq/3

[append4]
file_append=1
rw=write
bs=4k
direct=1
size=1024m
filename=/zone/seq/4

[append5]
file_append=1
rw=write
bs=4k
direct=1
size=1024m
filename=/zone/seq/5

...

Nothing fancy, but it will test the append path. I have been running the
ZenFS test suite as well, but that does not hit the append path. Maybe
if you run it against zonefs?

Best regards,
Andreas