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Commit ca4b2a01 authored by Matias Bjørling's avatar Matias Bjørling Committed by Jens Axboe
Browse files

null_blk: add zone support 



Adds support for exposing a null_blk device through the zone device
interface.

The interface is managed with the parameters zoned and zone_size.
If zoned is set, the null_blk instance registers as a zoned block
device. The zone_size parameter defines how big each zone will be.

Signed-off-by: default avatarMatias Bjørling <matias.bjorling@wdc.com>
Signed-off-by: default avatarBart Van Assche <bart.vanassche@wdc.com>
Signed-off-by: default avatarDamien Le Moal <damien.lemoal@wdc.com>
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 6dad38d3

Documentation/block/null_blk.txt

+7 −0
Original line number Diff line number Diff line
@@ -85,3 +85,10 @@ shared_tags=[0/1]: Default: 0 
  0: Tag set is not shared.

  1: Tag set shared between devices for blk-mq. Only makes sense with

     nr_devices > 1, otherwise there's no tag set to share.



zoned=[0/1]: Default: 0

  0: Block device is exposed as a random-access block device.

  1: Block device is exposed as a host-managed zoned block device.



zone_size=[MB]: Default: 256

  Per zone size when exposed as a zoned block device. Must be a power of two.

drivers/block/Makefile

+4 −1
Original line number Diff line number Diff line
@@ -36,8 +36,11 @@ obj-$(CONFIG_BLK_DEV_RBD) += rbd.o 
obj-$(CONFIG_BLK_DEV_PCIESSD_MTIP32XX)	+= mtip32xx/



obj-$(CONFIG_BLK_DEV_RSXX) += rsxx/

obj-$(CONFIG_BLK_DEV_NULL_BLK)	+= null_blk.o

obj-$(CONFIG_ZRAM) += zram/



obj-$(CONFIG_BLK_DEV_NULL_BLK)	+= null_blk_mod.o

null_blk_mod-objs	:= null_blk.o

null_blk_mod-$(CONFIG_BLK_DEV_ZONED) += null_blk_zoned.o



skd-y		:= skd_main.o

swim_mod-y	:= swim.o swim_asm.o

drivers/block/null_blk.c

+46 −2
Original line number Diff line number Diff line
@@ -180,6 +180,14 @@ static bool g_use_per_node_hctx; 
module_param_named(use_per_node_hctx, g_use_per_node_hctx, bool, 0444);

MODULE_PARM_DESC(use_per_node_hctx, "Use per-node allocation for hardware context queues. Default: false");



static bool g_zoned;

module_param_named(zoned, g_zoned, bool, S_IRUGO);

MODULE_PARM_DESC(zoned, "Make device as a host-managed zoned block device. Default: false");



static unsigned long g_zone_size = 256;

module_param_named(zone_size, g_zone_size, ulong, S_IRUGO);

MODULE_PARM_DESC(zone_size, "Zone size in MB when block device is zoned. Must be power-of-two: Default: 256");



static struct nullb_device *null_alloc_dev(void);

static void null_free_dev(struct nullb_device *dev);

static void null_del_dev(struct nullb *nullb);
@@ -283,6 +291,8 @@ NULLB_DEVICE_ATTR(memory_backed, bool); 
NULLB_DEVICE_ATTR(discard, bool);

NULLB_DEVICE_ATTR(mbps, uint);

NULLB_DEVICE_ATTR(cache_size, ulong);

NULLB_DEVICE_ATTR(zoned, bool);

NULLB_DEVICE_ATTR(zone_size, ulong);



static ssize_t nullb_device_power_show(struct config_item *item, char *page)

{
@@ -395,6 +405,8 @@ static struct configfs_attribute *nullb_device_attrs[] = { 
	&nullb_device_attr_mbps,

	&nullb_device_attr_cache_size,

	&nullb_device_attr_badblocks,

	&nullb_device_attr_zoned,

	&nullb_device_attr_zone_size,

	NULL,

};
@@ -447,7 +459,7 @@ nullb_group_drop_item(struct config_group *group, struct config_item *item) 


static ssize_t memb_group_features_show(struct config_item *item, char *page)

{

	return snprintf(page, PAGE_SIZE, "memory_backed,discard,bandwidth,cache,badblocks\n");

	return snprintf(page, PAGE_SIZE, "memory_backed,discard,bandwidth,cache,badblocks,zoned,zone_size\n");

}



CONFIGFS_ATTR_RO(memb_group_, features);
@@ -506,6 +518,8 @@ static struct nullb_device *null_alloc_dev(void) 
	dev->hw_queue_depth = g_hw_queue_depth;

	dev->blocking = g_blocking;

	dev->use_per_node_hctx = g_use_per_node_hctx;

	dev->zoned = g_zoned;

	dev->zone_size = g_zone_size;

	return dev;

}
@@ -514,6 +528,7 @@ static void null_free_dev(struct nullb_device *dev) 
	if (!dev)

		return;



	null_zone_exit(dev);

	badblocks_exit(&dev->badblocks);

	kfree(dev);

}
@@ -1146,6 +1161,11 @@ static blk_status_t null_handle_cmd(struct nullb_cmd *cmd) 
	struct nullb *nullb = dev->nullb;

	int err = 0;



	if (req_op(cmd->rq) == REQ_OP_ZONE_REPORT) {

		cmd->error = null_zone_report(nullb, cmd);

		goto out;

	}



	if (test_bit(NULLB_DEV_FL_THROTTLED, &dev->flags)) {

		struct request *rq = cmd->rq;
@@ -1210,6 +1230,13 @@ static blk_status_t null_handle_cmd(struct nullb_cmd *cmd) 
		}

	}

	cmd->error = errno_to_blk_status(err);



	if (!cmd->error && dev->zoned) {

		if (req_op(cmd->rq) == REQ_OP_WRITE)

			null_zone_write(cmd);

		else if (req_op(cmd->rq) == REQ_OP_ZONE_RESET)

			null_zone_reset(cmd);

	}

out:

	/* Complete IO by inline, softirq or timer */

	switch (dev->irqmode) {
@@ -1737,6 +1764,15 @@ static int null_add_dev(struct nullb_device *dev) 
		blk_queue_flush_queueable(nullb->q, true);

	}



	if (dev->zoned) {

		rv = null_zone_init(dev);

		if (rv)

			goto out_cleanup_blk_queue;



		blk_queue_chunk_sectors(nullb->q, dev->zone_size_sects);

		nullb->q->limits.zoned = BLK_ZONED_HM;

	}



	nullb->q->queuedata = nullb;

	blk_queue_flag_set(QUEUE_FLAG_NONROT, nullb->q);

	blk_queue_flag_clear(QUEUE_FLAG_ADD_RANDOM, nullb->q);
@@ -1755,13 +1791,16 @@ static int null_add_dev(struct nullb_device *dev) 


	rv = null_gendisk_register(nullb);

	if (rv)

		goto out_cleanup_blk_queue;

		goto out_cleanup_zone;



	mutex_lock(&lock);

	list_add_tail(&nullb->list, &nullb_list);

	mutex_unlock(&lock);



	return 0;

out_cleanup_zone:

	if (dev->zoned)

		null_zone_exit(dev);

out_cleanup_blk_queue:

	blk_cleanup_queue(nullb->q);

out_cleanup_tags:
@@ -1788,6 +1827,11 @@ static int __init null_init(void) 
		g_bs = PAGE_SIZE;

	}



	if (!is_power_of_2(g_zone_size)) {

		pr_err("null_blk: zone_size must be power-of-two\n");

		return -EINVAL;

	}



	if (g_queue_mode == NULL_Q_MQ && g_use_per_node_hctx) {

		if (g_submit_queues != nr_online_nodes) {

			pr_warn("null_blk: submit_queues param is set to %u.\n",

drivers/block/null_blk.h

+28 −0
Original line number Diff line number Diff line
@@ -41,9 +41,14 @@ struct nullb_device { 
	unsigned int curr_cache;

	struct badblocks badblocks;



	unsigned int nr_zones;

	struct blk_zone *zones;

	sector_t zone_size_sects;



	unsigned long size; /* device size in MB */

	unsigned long completion_nsec; /* time in ns to complete a request */

	unsigned long cache_size; /* disk cache size in MB */

	unsigned long zone_size; /* zone size in MB if device is zoned */

	unsigned int submit_queues; /* number of submission queues */

	unsigned int home_node; /* home node for the device */

	unsigned int queue_mode; /* block interface */
@@ -57,6 +62,7 @@ struct nullb_device { 
	bool power; /* power on/off the device */

	bool memory_backed; /* if data is stored in memory */

	bool discard; /* if support discard */

	bool zoned; /* if device is zoned */

};



struct nullb {
@@ -77,4 +83,26 @@ struct nullb { 
	unsigned int nr_queues;

	char disk_name[DISK_NAME_LEN];

};



#ifdef CONFIG_BLK_DEV_ZONED

int null_zone_init(struct nullb_device *dev);

void null_zone_exit(struct nullb_device *dev);

blk_status_t null_zone_report(struct nullb *nullb,

					    struct nullb_cmd *cmd);

void null_zone_write(struct nullb_cmd *cmd);

void null_zone_reset(struct nullb_cmd *cmd);

#else

static inline int null_zone_init(struct nullb_device *dev)

{

	return -EINVAL;

}

static inline void null_zone_exit(struct nullb_device *dev) {}

static inline blk_status_t null_zone_report(struct nullb *nullb,

					    struct nullb_cmd *cmd)

{

	return BLK_STS_NOTSUPP;

}

static inline void null_zone_write(struct nullb_cmd *cmd) {}

static inline void null_zone_reset(struct nullb_cmd *cmd) {}

#endif /* CONFIG_BLK_DEV_ZONED */

#endif /* __NULL_BLK_H */

drivers/block/null_blk_zoned.c

0 → 100644
+149 −0
Original line number Diff line number Diff line 
// SPDX-License-Identifier: GPL-2.0

#include <linux/vmalloc.h>

#include "null_blk.h"



/* zone_size in MBs to sectors. */

#define ZONE_SIZE_SHIFT		11



static inline unsigned int null_zone_no(struct nullb_device *dev, sector_t sect)

{

	return sect >> ilog2(dev->zone_size_sects);

}



int null_zone_init(struct nullb_device *dev)

{

	sector_t dev_size = (sector_t)dev->size * 1024 * 1024;

	sector_t sector = 0;

	unsigned int i;



	if (!is_power_of_2(dev->zone_size)) {

		pr_err("null_blk: zone_size must be power-of-two\n");

		return -EINVAL;

	}



	dev->zone_size_sects = dev->zone_size << ZONE_SIZE_SHIFT;

	dev->nr_zones = dev_size >>

				(SECTOR_SHIFT + ilog2(dev->zone_size_sects));

	dev->zones = kvmalloc_array(dev->nr_zones, sizeof(struct blk_zone),

			GFP_KERNEL | __GFP_ZERO);

	if (!dev->zones)

		return -ENOMEM;



	for (i = 0; i < dev->nr_zones; i++) {

		struct blk_zone *zone = &dev->zones[i];



		zone->start = zone->wp = sector;

		zone->len = dev->zone_size_sects;

		zone->type = BLK_ZONE_TYPE_SEQWRITE_REQ;

		zone->cond = BLK_ZONE_COND_EMPTY;



		sector += dev->zone_size_sects;

	}



	return 0;

}



void null_zone_exit(struct nullb_device *dev)

{

	kvfree(dev->zones);

}



static void null_zone_fill_rq(struct nullb_device *dev, struct request *rq,

			      unsigned int zno, unsigned int nr_zones)

{

	struct blk_zone_report_hdr *hdr = NULL;

	struct bio_vec bvec;

	struct bvec_iter iter;

	void *addr;

	unsigned int zones_to_cpy;



	bio_for_each_segment(bvec, rq->bio, iter) {

		addr = kmap_atomic(bvec.bv_page);



		zones_to_cpy = bvec.bv_len / sizeof(struct blk_zone);



		if (!hdr) {

			hdr = (struct blk_zone_report_hdr *)addr;

			hdr->nr_zones = nr_zones;

			zones_to_cpy--;

			addr += sizeof(struct blk_zone_report_hdr);

		}



		zones_to_cpy = min_t(unsigned int, zones_to_cpy, nr_zones);



		memcpy(addr, &dev->zones[zno],

				zones_to_cpy * sizeof(struct blk_zone));



		kunmap_atomic(addr);



		nr_zones -= zones_to_cpy;

		zno += zones_to_cpy;



		if (!nr_zones)

			break;

	}

}



blk_status_t null_zone_report(struct nullb *nullb,

				     struct nullb_cmd *cmd)

{

	struct nullb_device *dev = nullb->dev;

	struct request *rq = cmd->rq;

	unsigned int zno = null_zone_no(dev, blk_rq_pos(rq));

	unsigned int nr_zones = dev->nr_zones - zno;

	unsigned int max_zones = (blk_rq_bytes(rq) /

					sizeof(struct blk_zone)) - 1;



	nr_zones = min_t(unsigned int, nr_zones, max_zones);



	null_zone_fill_rq(nullb->dev, rq, zno, nr_zones);



	return BLK_STS_OK;

}



void null_zone_write(struct nullb_cmd *cmd)

{

	struct nullb_device *dev = cmd->nq->dev;

	struct request *rq = cmd->rq;

	sector_t sector = blk_rq_pos(rq);

	unsigned int rq_sectors = blk_rq_sectors(rq);

	unsigned int zno = null_zone_no(dev, sector);

	struct blk_zone *zone = &dev->zones[zno];



	switch (zone->cond) {

	case BLK_ZONE_COND_FULL:

		/* Cannot write to a full zone */

		cmd->error = BLK_STS_IOERR;

		break;

	case BLK_ZONE_COND_EMPTY:

	case BLK_ZONE_COND_IMP_OPEN:

		/* Writes must be at the write pointer position */

		if (blk_rq_pos(rq) != zone->wp) {

			cmd->error = BLK_STS_IOERR;

			break;

		}



		if (zone->cond == BLK_ZONE_COND_EMPTY)

			zone->cond = BLK_ZONE_COND_IMP_OPEN;



		zone->wp += rq_sectors;

		if (zone->wp == zone->start + zone->len)

			zone->cond = BLK_ZONE_COND_FULL;

		break;

	default:

		/* Invalid zone condition */

		cmd->error = BLK_STS_IOERR;

		break;

	}

}



void null_zone_reset(struct nullb_cmd *cmd)

{

	struct nullb_device *dev = cmd->nq->dev;

	struct request *rq = cmd->rq;

	unsigned int zno = null_zone_no(dev, blk_rq_pos(rq));

	struct blk_zone *zone = &dev->zones[zno];



	zone->cond = BLK_ZONE_COND_EMPTY;

	zone->wp = zone->start;

}