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@samsung.com>
---
 drivers/block/ublk_drv.c      | 145 ++++++++++++++++++++++++++++++++--
 include/uapi/linux/ublk_cmd.h |  18 +++++
 2 files changed, 157 insertions(+), 6 deletions(-)

diff --git a/drivers/block/ublk_drv.c b/drivers/block/ublk_drv.c
index 6368b56eacf1..9741b4b1647b 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;
@@ -212,6 +215,11 @@ 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 (IS_ENABLED(CONFIG_BLK_DEV_ZONED) &&
+	    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_discard_apply(struct ublk_device *ub)
@@ -227,6 +235,19 @@ static void ublk_dev_param_discard_apply(struct ublk_device *ub)
 	blk_queue_max_discard_segments(q, p->max_discard_segments);
 }
 
+static void ublk_dev_param_zoned_apply(struct ublk_device *ub)
+{
+	const struct ublk_param_zoned *p = &ub->params.zoned;
+
+	if (IS_ENABLED(CONFIG_BLK_DEV_ZONED) &&
+	    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);
+		/* We do not support zone append yet */
+		//blk_queue_max_zone_append_sectors(q, zone_size);
+	}
+}
+
 static int ublk_validate_params(const struct ublk_device *ub)
 {
 	/* basic param is the only one which must be set */
@@ -268,6 +289,9 @@ static int ublk_apply_params(struct ublk_device *ub)
 	if (ub->params.types & UBLK_PARAM_TYPE_DISCARD)
 		ublk_dev_param_discard_apply(ub);
 
+	if (ub->params.types & UBLK_PARAM_TYPE_ZONED)
+		ublk_dev_param_zoned_apply(ub);
+
 	return 0;
 }
 
@@ -361,9 +385,18 @@ static void ublk_free_disk(struct gendisk *disk)
 	put_device(&ub->cdev_dev);
 }
 
+#if IS_ENABLED(CONFIG_BLK_DEV_ZONED)
+static int ublk_report_zones(struct gendisk *disk, sector_t sector,
+			     unsigned int nr_zones, report_zones_cb cb,
+			     void *data);
+#endif
+
 static const struct block_device_operations ub_fops = {
-	.owner =	THIS_MODULE,
-	.free_disk =	ublk_free_disk,
+	.owner = THIS_MODULE,
+	.free_disk = ublk_free_disk,
+#if IS_ENABLED(CONFIG_BLK_DEV_ZONED)
+	.report_zones = ublk_report_zones,
+#endif
 };
 
 #define UBLK_MAX_PIN_PAGES	32
@@ -499,7 +532,7 @@ 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 +599,26 @@ 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
 	default:
 		return BLK_STS_IOERR;
 	}
@@ -612,7 +665,8 @@ 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;
 	}
@@ -1493,6 +1547,73 @@ static struct ublk_device *ublk_get_device_from_id(int idx)
 	return ub;
 }
 
+#ifdef CONFIG_BLK_DEV_ZONED
+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;
+
+		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;
+}
+#endif
+
 static int ublk_ctrl_start_dev(struct io_uring_cmd *cmd)
 {
 	struct ublksrv_ctrl_cmd *header = (struct ublksrv_ctrl_cmd *)cmd->cmd;
@@ -1535,6 +1656,15 @@ 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 = blk_revalidate_disk_zones(disk, NULL);
+		if (ret)
+			goto out_put_disk;
+	}
+
 	get_device(&ub->cdev_dev);
 	ret = add_disk(disk);
 	if (ret) {
@@ -1673,6 +1803,9 @@ 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;
+};
+
 struct ublk_params {
 	/*
 	 * Total length of parameters, userspace has to set 'len' for both
@@ -224,10 +240,12 @@ struct ublk_params {
 	__u32	len;
 #define UBLK_PARAM_TYPE_BASIC           (1 << 0)
 #define UBLK_PARAM_TYPE_DISCARD         (1 << 1)
+#define UBLK_PARAM_TYPE_ZONED           (1 << 2)
 	__u32	types;			/* types of parameter included */
 
 	struct ublk_param_basic		basic;
 	struct ublk_param_discard	discard;
+	struct ublk_param_zoned		zoned;
 };
 
 #endif
-- 
2.39.2

Hi Andreas,

Thank you for the patch! Yet something to improve:

[auto build test ERROR on v6.2]
[cannot apply to axboe-block/for-next linus/master next-20230224]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Andreas-Hindborg/block-ublk-enable-zoned-storage-support/20230224-210205
patch link:    https://lore.kernel.org/r/20230224125950.214779-1-nmi%40metaspace.dk
patch subject: [PATCH] block: ublk: enable zoned storage support
config: mips-allyesconfig (https://download.01.org/0day-ci/archive/20230225/202302250349.1eKfsTvO-lkp@intel.com/config)
compiler: mips-linux-gcc (GCC) 12.1.0
reproduce (this is a W=1 build):
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # https://github.com/intel-lab-lkp/linux/commit/6d088fc1b115a63e8888b12fa47aabd45be97460
        git remote add linux-review https://github.com/intel-lab-lkp/linux
        git fetch --no-tags linux-review Andreas-Hindborg/block-ublk-enable-zoned-storage-support/20230224-210205
        git checkout 6d088fc1b115a63e8888b12fa47aabd45be97460
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-12.1.0 make.cross W=1 O=build_dir ARCH=mips olddefconfig
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-12.1.0 make.cross W=1 O=build_dir ARCH=mips SHELL=/bin/bash

If you fix the issue, kindly add following tag where applicable
| Reported-by: kernel test robot <lkp@intel.com>
| Link: https://lore.kernel.org/oe-kbuild-all/202302250349.1eKfsTvO-lkp@intel.com/

All errors (new ones prefixed by >>):

   arch/mips/kernel/head.o: in function `kernel_entry':
   (.ref.text+0xac): relocation truncated to fit: R_MIPS_26 against `start_kernel'
   init/main.o: in function `set_reset_devices':
   main.c:(.init.text+0x20): relocation truncated to fit: R_MIPS_26 against `_mcount'
   main.c:(.init.text+0x30): relocation truncated to fit: R_MIPS_26 against `__sanitizer_cov_trace_pc'
   init/main.o: in function `debug_kernel':
   main.c:(.init.text+0xa4): relocation truncated to fit: R_MIPS_26 against `_mcount'
   main.c:(.init.text+0xb4): relocation truncated to fit: R_MIPS_26 against `__sanitizer_cov_trace_pc'
   init/main.o: in function `quiet_kernel':
   main.c:(.init.text+0x128): relocation truncated to fit: R_MIPS_26 against `_mcount'
   main.c:(.init.text+0x138): relocation truncated to fit: R_MIPS_26 against `__sanitizer_cov_trace_pc'
   init/main.o: in function `warn_bootconfig':
   main.c:(.init.text+0x1ac): relocation truncated to fit: R_MIPS_26 against `_mcount'
   main.c:(.init.text+0x1bc): relocation truncated to fit: R_MIPS_26 against `__sanitizer_cov_trace_pc'
   init/main.o: in function `init_setup':
   main.c:(.init.text+0x234): relocation truncated to fit: R_MIPS_26 against `_mcount'
   main.c:(.init.text+0x254): additional relocation overflows omitted from the output
   mips-linux-ld: drivers/block/ublk_drv.o: in function `ublk_dev_param_basic_apply':
>> ublk_drv.c:(.text.ublk_dev_param_basic_apply+0x2d8): undefined reference to `__udivdi3'

-- 
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests

Hi Andreas,

Thank you for the patch! Yet something to improve:

[auto build test ERROR on v6.2]
[cannot apply to axboe-block/for-next linus/master next-20230224]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Andreas-Hindborg/block-ublk-enable-zoned-storage-support/20230224-210205
patch link:    https://lore.kernel.org/r/20230224125950.214779-1-nmi%40metaspace.dk
patch subject: [PATCH] block: ublk: enable zoned storage support
config: ia64-buildonly-randconfig-r006-20230222 (https://download.01.org/0day-ci/archive/20230225/202302250222.XOrw9j6z-lkp@intel.com/config)
compiler: ia64-linux-gcc (GCC) 12.1.0
reproduce (this is a W=1 build):
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # https://github.com/intel-lab-lkp/linux/commit/6d088fc1b115a63e8888b12fa47aabd45be97460
        git remote add linux-review https://github.com/intel-lab-lkp/linux
        git fetch --no-tags linux-review Andreas-Hindborg/block-ublk-enable-zoned-storage-support/20230224-210205
        git checkout 6d088fc1b115a63e8888b12fa47aabd45be97460
        # save the config file
        mkdir build_dir && cp config build_dir/.config
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-12.1.0 make.cross W=1 O=build_dir ARCH=ia64 olddefconfig
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-12.1.0 make.cross W=1 O=build_dir ARCH=ia64 SHELL=/bin/bash drivers/

If you fix the issue, kindly add following tag where applicable
| Reported-by: kernel test robot <lkp@intel.com>
| Link: https://lore.kernel.org/oe-kbuild-all/202302250222.XOrw9j6z-lkp@intel.com/

All errors (new ones prefixed by >>):

   drivers/block/ublk_drv.c: In function 'ublk_dev_param_basic_apply':
>> drivers/block/ublk_drv.c:221:28: error: 'struct gendisk' has no member named 'nr_zones'
     221 |                 ub->ub_disk->nr_zones = p->dev_sectors / p->chunk_sectors;
         |                            ^~
   drivers/block/ublk_drv.c: In function 'ublk_dev_param_zoned_apply':
>> drivers/block/ublk_drv.c:244:17: error: implicit declaration of function 'disk_set_max_active_zones'; did you mean 'bdev_max_active_zones'? [-Werror=implicit-function-declaration]
     244 |                 disk_set_max_active_zones(ub->ub_disk, p->max_active_zones);
         |                 ^~~~~~~~~~~~~~~~~~~~~~~~~
         |                 bdev_max_active_zones
>> drivers/block/ublk_drv.c:245:17: error: implicit declaration of function 'disk_set_max_open_zones'; did you mean 'bdev_max_open_zones'? [-Werror=implicit-function-declaration]
     245 |                 disk_set_max_open_zones(ub->ub_disk, p->max_open_zones);
         |                 ^~~~~~~~~~~~~~~~~~~~~~~
         |                 bdev_max_open_zones
   drivers/block/ublk_drv.c: In function 'ublk_ctrl_start_dev':
>> drivers/block/ublk_drv.c:1663:23: error: implicit declaration of function 'blk_revalidate_disk_zones' [-Werror=implicit-function-declaration]
    1663 |                 ret = blk_revalidate_disk_zones(disk, NULL);
         |                       ^~~~~~~~~~~~~~~~~~~~~~~~~
   cc1: some warnings being treated as errors


vim +221 drivers/block/ublk_drv.c

   192	
   193	static void ublk_dev_param_basic_apply(struct ublk_device *ub)
   194	{
   195		struct request_queue *q = ub->ub_disk->queue;
   196		const struct ublk_param_basic *p = &ub->params.basic;
   197	
   198		blk_queue_logical_block_size(q, 1 << p->logical_bs_shift);
   199		blk_queue_physical_block_size(q, 1 << p->physical_bs_shift);
   200		blk_queue_io_min(q, 1 << p->io_min_shift);
   201		blk_queue_io_opt(q, 1 << p->io_opt_shift);
   202	
   203		blk_queue_write_cache(q, p->attrs & UBLK_ATTR_VOLATILE_CACHE,
   204				p->attrs & UBLK_ATTR_FUA);
   205		if (p->attrs & UBLK_ATTR_ROTATIONAL)
   206			blk_queue_flag_clear(QUEUE_FLAG_NONROT, q);
   207		else
   208			blk_queue_flag_set(QUEUE_FLAG_NONROT, q);
   209	
   210		blk_queue_max_hw_sectors(q, p->max_sectors);
   211		blk_queue_chunk_sectors(q, p->chunk_sectors);
   212		blk_queue_virt_boundary(q, p->virt_boundary_mask);
   213	
   214		if (p->attrs & UBLK_ATTR_READ_ONLY)
   215			set_disk_ro(ub->ub_disk, true);
   216	
   217		set_capacity(ub->ub_disk, p->dev_sectors);
   218	
   219		if (IS_ENABLED(CONFIG_BLK_DEV_ZONED) &&
   220		    ub->dev_info.flags & UBLK_F_ZONED && p->chunk_sectors) {
 > 221			ub->ub_disk->nr_zones = p->dev_sectors / p->chunk_sectors;
   222		}
   223	}
   224	
   225	static void ublk_dev_param_discard_apply(struct ublk_device *ub)
   226	{
   227		struct request_queue *q = ub->ub_disk->queue;
   228		const struct ublk_param_discard *p = &ub->params.discard;
   229	
   230		q->limits.discard_alignment = p->discard_alignment;
   231		q->limits.discard_granularity = p->discard_granularity;
   232		blk_queue_max_discard_sectors(q, p->max_discard_sectors);
   233		blk_queue_max_write_zeroes_sectors(q,
   234				p->max_write_zeroes_sectors);
   235		blk_queue_max_discard_segments(q, p->max_discard_segments);
   236	}
   237	
   238	static void ublk_dev_param_zoned_apply(struct ublk_device *ub)
   239	{
   240		const struct ublk_param_zoned *p = &ub->params.zoned;
   241	
   242		if (IS_ENABLED(CONFIG_BLK_DEV_ZONED) &&
   243		    ub->dev_info.flags & UBLK_F_ZONED) {
 > 244			disk_set_max_active_zones(ub->ub_disk, p->max_active_zones);
 > 245			disk_set_max_open_zones(ub->ub_disk, p->max_open_zones);
   246			/* We do not support zone append yet */
   247			//blk_queue_max_zone_append_sectors(q, zone_size);
   248		}
   249	}
   250	

-- 
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests

Hello Andreas,

On Fri, Feb 24, 2023 at 01:59:50PM +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@samsung.com>
> ---

Did you try to build this patch with CONFIG_BLK_DEV_ZONED disabled?

I got the following build errors when building it on top of vanilla v6.2
when CONFIG_BLK_DEV_ZONED is disabled:

drivers/block/ublk_drv.c: In function ‘ublk_dev_param_basic_apply’:
drivers/block/ublk_drv.c:221:28: error: ‘struct gendisk’ has no member named ‘nr_zones’
  221 |                 ub->ub_disk->nr_zones = p->dev_sectors / p->chunk_sectors;
      |                            ^~
drivers/block/ublk_drv.c: In function ‘ublk_dev_param_zoned_apply’:
drivers/block/ublk_drv.c:244:17: error: implicit declaration of function ‘disk_set_max_active_zones’; did you mean ‘bdev_max_active_zones’? [-Werror=implicit-function-declaration]
  244 |                 disk_set_max_active_zones(ub->ub_disk, p->max_active_zones);
      |                 ^~~~~~~~~~~~~~~~~~~~~~~~~
      |                 bdev_max_active_zones
drivers/block/ublk_drv.c:245:17: error: implicit declaration of function ‘disk_set_max_open_zones’; did you mean ‘bdev_max_open_zones’? [-Werror=implicit-function-declaration]
  245 |                 disk_set_max_open_zones(ub->ub_disk, p->max_open_zones);


>  drivers/block/ublk_drv.c      | 145 ++++++++++++++++++++++++++++++++--
>  include/uapi/linux/ublk_cmd.h |  18 +++++
>  2 files changed, 157 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/block/ublk_drv.c b/drivers/block/ublk_drv.c
> index 6368b56eacf1..9741b4b1647b 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;
> @@ -212,6 +215,11 @@ 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 (IS_ENABLED(CONFIG_BLK_DEV_ZONED) &&
> +	    ub->dev_info.flags & UBLK_F_ZONED && p->chunk_sectors) {
> +		ub->ub_disk->nr_zones = p->dev_sectors / p->chunk_sectors;
> +	}

Kernel coding style says to not unnecessarily use braces where a single
statement will do:
https://www.kernel.org/doc/html/latest/process/coding-style.html#placing-braces-and-spaces

>  }
>  
>  static void ublk_dev_param_discard_apply(struct ublk_device *ub)
> @@ -227,6 +235,19 @@ static void ublk_dev_param_discard_apply(struct ublk_device *ub)
>  	blk_queue_max_discard_segments(q, p->max_discard_segments);
>  }
>  
> +static void ublk_dev_param_zoned_apply(struct ublk_device *ub)
> +{
> +	const struct ublk_param_zoned *p = &ub->params.zoned;
> +
> +	if (IS_ENABLED(CONFIG_BLK_DEV_ZONED) &&
> +	    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);
> +		/* We do not support zone append yet */
> +		//blk_queue_max_zone_append_sectors(q, zone_size);

Remove commented out code.
It can be added once that feature is added.

> +	}
> +}
> +
>  static int ublk_validate_params(const struct ublk_device *ub)
>  {
>  	/* basic param is the only one which must be set */
> @@ -268,6 +289,9 @@ static int ublk_apply_params(struct ublk_device *ub)
>  	if (ub->params.types & UBLK_PARAM_TYPE_DISCARD)
>  		ublk_dev_param_discard_apply(ub);
>  
> +	if (ub->params.types & UBLK_PARAM_TYPE_ZONED)
> +		ublk_dev_param_zoned_apply(ub);
> +
>  	return 0;
>  }
>  
> @@ -361,9 +385,18 @@ static void ublk_free_disk(struct gendisk *disk)
>  	put_device(&ub->cdev_dev);
>  }
>  
> +#if IS_ENABLED(CONFIG_BLK_DEV_ZONED)

Here you use "#if IS_ENABLED(CONFIG_BLK_DEV_ZONED)"
yet further down you use
"#ifdef CONFIG_BLK_DEV_ZONED".

IS_ENABLED() is usually used when testing for a Kconfig within
a normal C conditional, e.g. if (IS_ENABLED()), where possible,
in order to avoid ugly C preprocessor conditionals completely.

However, if you have to use C preprocessor conditionals, then
#ifdef CONFIG_SOMETHING
is the most common way to conditionally include something.

> +static int ublk_report_zones(struct gendisk *disk, sector_t sector,
> +			     unsigned int nr_zones, report_zones_cb cb,
> +			     void *data);
> +#endif
> +
>  static const struct block_device_operations ub_fops = {
> -	.owner =	THIS_MODULE,
> -	.free_disk =	ublk_free_disk,
> +	.owner = THIS_MODULE,
> +	.free_disk = ublk_free_disk,
> +#if IS_ENABLED(CONFIG_BLK_DEV_ZONED)
> +	.report_zones = ublk_report_zones,
> +#endif
>  };
>  
>  #define UBLK_MAX_PIN_PAGES	32
> @@ -499,7 +532,7 @@ 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 +599,26 @@ 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
>  	default:
>  		return BLK_STS_IOERR;
>  	}
> @@ -612,7 +665,8 @@ 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;
>  	}
> @@ -1493,6 +1547,73 @@ static struct ublk_device *ublk_get_device_from_id(int idx)
>  	return ub;
>  }
>  
> +#ifdef CONFIG_BLK_DEV_ZONED
> +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++) {
> +

No need for empty line here.

> +		struct request *req;
> +		blk_status_t status;
> +		struct blk_zone info;

Since this is allocated on the stack, does it need memset()?

null_blk seems to memset blk_zone before the loop, but not inside the loop:
https://github.com/torvalds/linux/blob/v6.2/drivers/block/null_blk/zoned.c#L206

So I'm a bit confused...

If e.g. cb() is blkdev_copy_zone_to_user()
https://github.com/torvalds/linux/blob/v6.2/block/blk-zoned.c#L318

It will copy whatever the kernel allocated.
So I guess that since you can't guarantee that the ublk user space driver
will fill in all fields in the zone when receiving a REQ_OP_DRV_IN,
I assume that you do need to do a memset() in order to not potentially
leak kernel space data.


> +
> +		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;
> +}
> +#endif
> +
>  static int ublk_ctrl_start_dev(struct io_uring_cmd *cmd)
>  {
>  	struct ublksrv_ctrl_cmd *header = (struct ublksrv_ctrl_cmd *)cmd->cmd;
> @@ -1535,6 +1656,15 @@ 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 = blk_revalidate_disk_zones(disk, NULL);
> +		if (ret)
> +			goto out_put_disk;
> +	}
> +
>  	get_device(&ub->cdev_dev);
>  	ret = add_disk(disk);
>  	if (ret) {
> @@ -1673,6 +1803,9 @@ 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;
> +};
> +
>  struct ublk_params {
>  	/*
>  	 * Total length of parameters, userspace has to set 'len' for both
> @@ -224,10 +240,12 @@ struct ublk_params {
>  	__u32	len;
>  #define UBLK_PARAM_TYPE_BASIC           (1 << 0)
>  #define UBLK_PARAM_TYPE_DISCARD         (1 << 1)
> +#define UBLK_PARAM_TYPE_ZONED           (1 << 2)
>  	__u32	types;			/* types of parameter included */
>  
>  	struct ublk_param_basic		basic;
>  	struct ublk_param_discard	discard;
> +	struct ublk_param_zoned		zoned;
>  };
>  
>  #endif
> -- 
> 2.39.2
> 

On Fri, Feb 24, 2023 at 04:53:52PM +0100, Niklas Cassel wrote:
> Hello Andreas,
> 
> On Fri, Feb 24, 2023 at 01:59:50PM +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@samsung.com>
> > ---
> 
> Did you try to build this patch with CONFIG_BLK_DEV_ZONED disabled?
> 
> I got the following build errors when building it on top of vanilla v6.2
> when CONFIG_BLK_DEV_ZONED is disabled:
> 
> drivers/block/ublk_drv.c: In function ‘ublk_dev_param_basic_apply’:
> drivers/block/ublk_drv.c:221:28: error: ‘struct gendisk’ has no member named ‘nr_zones’
>   221 |                 ub->ub_disk->nr_zones = p->dev_sectors / p->chunk_sectors;
>       |                            ^~
> drivers/block/ublk_drv.c: In function ‘ublk_dev_param_zoned_apply’:
> drivers/block/ublk_drv.c:244:17: error: implicit declaration of function ‘disk_set_max_active_zones’; did you mean ‘bdev_max_active_zones’? [-Werror=implicit-function-declaration]
>   244 |                 disk_set_max_active_zones(ub->ub_disk, p->max_active_zones);
>       |                 ^~~~~~~~~~~~~~~~~~~~~~~~~
>       |                 bdev_max_active_zones
> drivers/block/ublk_drv.c:245:17: error: implicit declaration of function ‘disk_set_max_open_zones’; did you mean ‘bdev_max_open_zones’? [-Werror=implicit-function-declaration]
>   245 |                 disk_set_max_open_zones(ub->ub_disk, p->max_open_zones);
> 

The problem here is probably that blkdev.h does not have dummy functions for
disk_set_max_active_zones() and disk_set_max_open_zones()

in the:
#else /* CONFIG_BLK_DEV_ZONED */
case.

I do see dummy functions in blkdev.h for disk_nr_zones(), disk_zone_is_seq()
and disk_zone_no() when CONFIG_BLK_DEV_ZONED is not set.


Kind regards,
Niklas

Niklas Cassel <Niklas.Cassel@wdc.com> writes:

> On Fri, Feb 24, 2023 at 04:53:52PM +0100, Niklas Cassel wrote:
>> Hello Andreas,
>> 
>> On Fri, Feb 24, 2023 at 01:59:50PM +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@samsung.com>
>> > ---
>> 
>> Did you try to build this patch with CONFIG_BLK_DEV_ZONED disabled?
>> 
>> I got the following build errors when building it on top of vanilla v6.2
>> when CONFIG_BLK_DEV_ZONED is disabled:
>> 
>> drivers/block/ublk_drv.c: In function ‘ublk_dev_param_basic_apply’:
>> drivers/block/ublk_drv.c:221:28: error: ‘struct gendisk’ has no member named ‘nr_zones’
>>   221 |                 ub->ub_disk->nr_zones = p->dev_sectors / p->chunk_sectors;
>>       |                            ^~
>> drivers/block/ublk_drv.c: In function ‘ublk_dev_param_zoned_apply’:
>> drivers/block/ublk_drv.c:244:17: error: implicit declaration of function ‘disk_set_max_active_zones’; did you mean ‘bdev_max_active_zones’? [-Werror=implicit-function-declaration]
>>   244 |                 disk_set_max_active_zones(ub->ub_disk, p->max_active_zones);
>>       |                 ^~~~~~~~~~~~~~~~~~~~~~~~~
>>       |                 bdev_max_active_zones
>> drivers/block/ublk_drv.c:245:17: error: implicit declaration of function ‘disk_set_max_open_zones’; did you mean ‘bdev_max_open_zones’? [-Werror=implicit-function-declaration]
>>   245 |                 disk_set_max_open_zones(ub->ub_disk, p->max_open_zones);
>> 
>
> The problem here is probably that blkdev.h does not have dummy functions for
> disk_set_max_active_zones() and disk_set_max_open_zones()
>
> in the:
> #else /* CONFIG_BLK_DEV_ZONED */
> case.
>
> I do see dummy functions in blkdev.h for disk_nr_zones(), disk_zone_is_seq()
> and disk_zone_no() when CONFIG_BLK_DEV_ZONED is not set.

Thanks for the comments Niklas :)

I completely forgot to test without CONFIG_BLK_DEV_ZONED 🤦 What is the
preferred resolution here? Conditionally remove the lines with #ifdef
rather than use if(IS_ENABLED(...))? Dummy functions would resolve lines
244 and 245, but would not help with assignment of nr_zones at 221 as
that will not exist when CONFIG_BLK_DEV_ZONED is disabled.

BR Andreas