Resguardo inicial

linux-7.2.3/drivers/block/null_blk/Kconfig

@@ -0,0 +1,12 @@
+# SPDX-License-Identifier: GPL-2.0
+#
+# Null block device driver configuration
+#
+
+config BLK_DEV_NULL_BLK
+	tristate "Null test block driver"
+	select CONFIGFS_FS
+
+config BLK_DEV_NULL_BLK_FAULT_INJECTION
+	bool "Support fault injection for Null test block driver"
+	depends on BLK_DEV_NULL_BLK && FAULT_INJECTION_CONFIGFS

linux-7.2.3/drivers/block/null_blk/Makefile

@@ -0,0 +1,11 @@
+# SPDX-License-Identifier: GPL-2.0
+
+# needed for trace events
+ccflags-y			+= -I$(src)
+
+obj-$(CONFIG_BLK_DEV_NULL_BLK)	+= null_blk.o
+null_blk-objs			:= main.o
+ifeq ($(CONFIG_BLK_DEV_ZONED), y)
+null_blk-$(CONFIG_TRACING) 	+= trace.o
+endif
+null_blk-$(CONFIG_BLK_DEV_ZONED) += zoned.o

linux-7.2.3/drivers/block/null_blk/null_blk.h

@@ -0,0 +1,185 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __BLK_NULL_BLK_H
+#define __BLK_NULL_BLK_H
+
+#undef pr_fmt
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/blkdev.h>
+#include <linux/slab.h>
+#include <linux/blk-mq.h>
+#include <linux/hrtimer.h>
+#include <linux/configfs.h>
+#include <linux/badblocks.h>
+#include <linux/fault-inject.h>
+#include <linux/spinlock.h>
+#include <linux/mutex.h>
+
+struct nullb_cmd {
+	blk_status_t error;
+	bool fake_timeout;
+	struct nullb_queue *nq;
+	struct hrtimer timer;
+};
+
+struct nullb_queue {
+	struct nullb_device *dev;
+	unsigned int requeue_selection;
+
+	struct list_head poll_list;
+	spinlock_t poll_lock;
+};
+
+struct nullb_zone {
+	/*
+	 * Zone lock to prevent concurrent modification of a zone write
+	 * pointer position and condition: with memory backing, a write
+	 * command execution may sleep on memory allocation. For this case,
+	 * use mutex as the zone lock. Otherwise, use the spinlock for
+	 * locking the zone.
+	 */
+	union {
+		spinlock_t spinlock;
+		struct mutex mutex;
+	};
+	enum blk_zone_type type;
+	enum blk_zone_cond cond;
+	sector_t start;
+	sector_t wp;
+	unsigned int len;
+	unsigned int capacity;
+};
+
+struct nullb_device {
+	struct nullb *nullb;
+	struct config_group group;
+#ifdef CONFIG_BLK_DEV_NULL_BLK_FAULT_INJECTION
+	struct fault_config timeout_config;
+	struct fault_config requeue_config;
+	struct fault_config init_hctx_fault_config;
+#endif
+	struct radix_tree_root data; /* data stored in the disk */
+	struct radix_tree_root cache; /* disk cache data */
+	unsigned long flags; /* device flags */
+	unsigned int curr_cache;
+	struct badblocks badblocks;
+	bool badblocks_once;
+	bool badblocks_partial_io;
+
+	unsigned int nr_zones;
+	unsigned int nr_zones_imp_open;
+	unsigned int nr_zones_exp_open;
+	unsigned int nr_zones_closed;
+	unsigned int imp_close_zone_no;
+	struct nullb_zone *zones;
+	sector_t zone_size_sects;
+	bool need_zone_res_mgmt;
+	spinlock_t zone_res_lock;
+
+	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 long zone_capacity; /* zone capacity in MB if device is zoned */
+	unsigned int zone_nr_conv; /* number of conventional zones */
+	unsigned int zone_max_open; /* max number of open zones */
+	unsigned int zone_max_active; /* max number of active zones */
+	unsigned int zone_append_max_sectors; /* Max sectors per zone append command */
+	unsigned int submit_queues; /* number of submission queues */
+	unsigned int prev_submit_queues; /* number of submission queues before change */
+	unsigned int poll_queues; /* number of IOPOLL submission queues */
+	unsigned int prev_poll_queues; /* number of IOPOLL submission queues before change */
+	unsigned int home_node; /* home node for the device */
+	unsigned int queue_mode; /* block interface */
+	unsigned int blocksize; /* block size */
+	unsigned int max_sectors; /* Max sectors per command */
+	unsigned int irqmode; /* IRQ completion handler */
+	unsigned int hw_queue_depth; /* queue depth */
+	unsigned int index; /* index of the disk, only valid with a disk */
+	unsigned int mbps; /* Bandwidth throttle cap (in MB/s) */
+	bool blocking; /* blocking blk-mq device */
+	bool use_per_node_hctx; /* use per-node allocation for hardware context */
+	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 */
+	bool zone_full; /* Initialize zones to be full */
+	bool virt_boundary; /* virtual boundary on/off for the device */
+	bool no_sched; /* no IO scheduler for the device */
+	bool shared_tags; /* share tag set between devices for blk-mq */
+	bool shared_tag_bitmap; /* use hostwide shared tags */
+	bool fua; /* Support FUA */
+	bool rotational; /* Fake rotational device */
+};
+
+struct nullb {
+	struct nullb_device *dev;
+	struct list_head list;
+	unsigned int index;
+	struct request_queue *q;
+	struct gendisk *disk;
+	struct blk_mq_tag_set *tag_set;
+	struct blk_mq_tag_set __tag_set;
+	atomic_long_t cur_bytes;
+	struct hrtimer bw_timer;
+	unsigned long cache_flush_pos;
+	spinlock_t lock;
+
+	struct nullb_queue *queues;
+	char disk_name[DISK_NAME_LEN];
+};
+
+blk_status_t null_handle_discard(struct nullb_device *dev, sector_t sector,
+				 sector_t nr_sectors);
+blk_status_t null_process_cmd(struct nullb_cmd *cmd, enum req_op op,
+			      sector_t sector, unsigned int nr_sectors);
+blk_status_t null_handle_badblocks(struct nullb_cmd *cmd, sector_t sector,
+				   unsigned int *nr_sectors);
+blk_status_t null_handle_memory_backed(struct nullb_cmd *cmd, enum req_op op,
+				       sector_t sector, sector_t nr_sectors);
+
+#ifdef CONFIG_BLK_DEV_ZONED
+int null_init_zoned_dev(struct nullb_device *dev, struct queue_limits *lim);
+int null_register_zoned_dev(struct nullb *nullb);
+void null_free_zoned_dev(struct nullb_device *dev);
+int null_report_zones(struct gendisk *disk, sector_t sector,
+		      unsigned int nr_zones,
+		      struct blk_report_zones_args *args);
+blk_status_t null_process_zoned_cmd(struct nullb_cmd *cmd, enum req_op op,
+				    sector_t sector, sector_t nr_sectors);
+size_t null_zone_valid_read_len(struct nullb *nullb,
+				sector_t sector, unsigned int len);
+ssize_t zone_cond_store(struct nullb_device *dev, const char *page,
+			size_t count, enum blk_zone_cond cond);
+#else
+static inline int null_init_zoned_dev(struct nullb_device *dev,
+		struct queue_limits *lim)
+{
+	pr_err("CONFIG_BLK_DEV_ZONED not enabled\n");
+	return -EINVAL;
+}
+static inline int null_register_zoned_dev(struct nullb *nullb)
+{
+	return -ENODEV;
+}
+static inline void null_free_zoned_dev(struct nullb_device *dev) {}
+static inline blk_status_t null_process_zoned_cmd(struct nullb_cmd *cmd,
+			enum req_op op, sector_t sector, sector_t nr_sectors)
+{
+	return BLK_STS_NOTSUPP;
+}
+static inline size_t null_zone_valid_read_len(struct nullb *nullb,
+					      sector_t sector,
+					      unsigned int len)
+{
+	return len;
+}
+static inline ssize_t zone_cond_store(struct nullb_device *dev,
+				      const char *page, size_t count,
+				      enum blk_zone_cond cond)
+{
+	return -EOPNOTSUPP;
+}
+#define null_report_zones	NULL
+#endif /* CONFIG_BLK_DEV_ZONED */
+#endif /* __NULL_BLK_H */

linux-7.2.3/drivers/block/null_blk/trace.c

@@ -0,0 +1,21 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * null_blk trace related helpers.
+ *
+ * Copyright (C) 2020 Western Digital Corporation or its affiliates.
+ */
+#include "trace.h"
+
+/*
+ * Helper to use for all null_blk traces to extract disk name.
+ */
+const char *nullb_trace_disk_name(struct trace_seq *p, char *name)
+{
+	const char *ret = trace_seq_buffer_ptr(p);
+
+	if (name && *name)
+		trace_seq_printf(p, "disk=%s, ", name);
+	trace_seq_putc(p, 0);
+
+	return ret;
+}

linux-7.2.3/drivers/block/null_blk/trace.h

@@ -0,0 +1,85 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/*
+ * null_blk device driver tracepoints.
+ *
+ * Copyright (C) 2020 Western Digital Corporation or its affiliates.
+ */
+
+#undef TRACE_SYSTEM
+#define TRACE_SYSTEM nullb
+
+#if !defined(_TRACE_NULLB_H) || defined(TRACE_HEADER_MULTI_READ)
+#define _TRACE_NULLB_H
+
+#include <linux/tracepoint.h>
+#include <linux/trace_seq.h>
+
+#include "null_blk.h"
+
+const char *nullb_trace_disk_name(struct trace_seq *p, char *name);
+
+#define __print_disk_name(name) nullb_trace_disk_name(p, name)
+
+#ifndef TRACE_HEADER_MULTI_READ
+static inline void __assign_disk_name(char *name, struct gendisk *disk)
+{
+	if (disk)
+		memcpy(name, disk->disk_name, DISK_NAME_LEN);
+	else
+		memset(name, 0, DISK_NAME_LEN);
+}
+#endif
+
+TRACE_EVENT(nullb_zone_op,
+	    TP_PROTO(struct nullb_cmd *cmd, unsigned int zone_no,
+		     unsigned int zone_cond),
+	    TP_ARGS(cmd, zone_no, zone_cond),
+	    TP_STRUCT__entry(
+		__array(char, disk, DISK_NAME_LEN)
+		/*
+		 * __field() uses is_signed_type(). is_signed_type() does not
+		 * support bitwise types. Use __field_struct() instead because
+		 * it does not use is_signed_type().
+		 */
+		__field_struct(enum req_op, op)
+		__field(unsigned int, zone_no)
+		__field(unsigned int, zone_cond)
+	    ),
+	    TP_fast_assign(
+		__entry->op = req_op(blk_mq_rq_from_pdu(cmd));
+		__entry->zone_no = zone_no;
+		__entry->zone_cond = zone_cond;
+		__assign_disk_name(__entry->disk,
+			blk_mq_rq_from_pdu(cmd)->q->disk);
+	    ),
+	    TP_printk("%s req=%-15s zone_no=%u zone_cond=%-10s",
+		      __print_disk_name(__entry->disk),
+		      blk_op_str(__entry->op),
+		      __entry->zone_no,
+		      blk_zone_cond_str(__entry->zone_cond))
+);
+
+TRACE_EVENT(nullb_report_zones,
+	    TP_PROTO(struct nullb *nullb, unsigned int nr_zones),
+	    TP_ARGS(nullb, nr_zones),
+	    TP_STRUCT__entry(
+		__array(char, disk, DISK_NAME_LEN)
+		__field(unsigned int, nr_zones)
+	    ),
+	    TP_fast_assign(
+		__entry->nr_zones = nr_zones;
+		__assign_disk_name(__entry->disk, nullb->disk);
+	    ),
+	    TP_printk("%s nr_zones=%u",
+		      __print_disk_name(__entry->disk), __entry->nr_zones)
+);
+
+#endif /* _TRACE_NULLB_H */
+
+#undef TRACE_INCLUDE_PATH
+#define TRACE_INCLUDE_PATH .
+#undef TRACE_INCLUDE_FILE
+#define TRACE_INCLUDE_FILE trace
+
+/* This part must be outside protection */
+#include <trace/define_trace.h>

linux-7.2.3/drivers/block/null_blk/zoned.c

@@ -0,0 +1,819 @@
+// SPDX-License-Identifier: GPL-2.0
+#include <linux/vmalloc.h>
+#include <linux/bitmap.h>
+#include "null_blk.h"
+
+#define CREATE_TRACE_POINTS
+#include "trace.h"
+
+#undef pr_fmt
+#define pr_fmt(fmt)	"null_blk: " fmt
+
+#define NULL_ZONE_INVALID_WP	((sector_t)-1)
+
+static inline sector_t mb_to_sects(unsigned long mb)
+{
+	return ((sector_t)mb * SZ_1M) >> SECTOR_SHIFT;
+}
+
+static inline unsigned int null_zone_no(struct nullb_device *dev, sector_t sect)
+{
+	if (WARN_ON_ONCE(!dev->zone_size_sects))
+		return 0;
+	return sect >> ilog2(dev->zone_size_sects);
+}
+
+static inline void null_init_zone_lock(struct nullb_device *dev,
+				       struct nullb_zone *zone)
+{
+	if (!dev->memory_backed)
+		spin_lock_init(&zone->spinlock);
+	else
+		mutex_init(&zone->mutex);
+}
+
+static inline void null_lock_zone(struct nullb_device *dev,
+				  struct nullb_zone *zone)
+{
+	if (!dev->memory_backed)
+		spin_lock_irq(&zone->spinlock);
+	else
+		mutex_lock(&zone->mutex);
+}
+
+static inline void null_unlock_zone(struct nullb_device *dev,
+				    struct nullb_zone *zone)
+{
+	if (!dev->memory_backed)
+		spin_unlock_irq(&zone->spinlock);
+	else
+		mutex_unlock(&zone->mutex);
+}
+
+int null_init_zoned_dev(struct nullb_device *dev,
+			struct queue_limits *lim)
+{
+	sector_t dev_capacity_sects, zone_capacity_sects;
+	struct nullb_zone *zone;
+	sector_t sector = 0;
+	unsigned int i;
+
+	if (!dev->zone_size || !is_power_of_2(dev->zone_size)) {
+		pr_err("zone_size must be non-zero power-of-two\n");
+		return -EINVAL;
+	}
+	if (dev->zone_size > dev->size) {
+		pr_err("Zone size larger than device capacity\n");
+		return -EINVAL;
+	}
+
+	if (!dev->zone_capacity)
+		dev->zone_capacity = dev->zone_size;
+
+	if (dev->zone_capacity > dev->zone_size) {
+		pr_err("zone capacity (%lu MB) larger than zone size (%lu MB)\n",
+		       dev->zone_capacity, dev->zone_size);
+		return -EINVAL;
+	}
+
+	/*
+	 * If a smaller zone capacity was requested, do not allow a smaller last
+	 * zone at the same time as such zone configuration does not correspond
+	 * to any real zoned device.
+	 */
+	if (dev->zone_capacity != dev->zone_size &&
+	    dev->size & (dev->zone_size - 1)) {
+		pr_err("A smaller last zone is not allowed with zone capacity smaller than zone size.\n");
+		return -EINVAL;
+	}
+
+	zone_capacity_sects = mb_to_sects(dev->zone_capacity);
+	dev_capacity_sects = mb_to_sects(dev->size);
+	dev->zone_size_sects = mb_to_sects(dev->zone_size);
+	if (!dev->zone_size_sects) {
+		pr_err("zone_size too large or too small, leads to zero sectors\n");
+		return -EINVAL;
+	}
+	dev->nr_zones = round_up(dev_capacity_sects, dev->zone_size_sects)
+		>> ilog2(dev->zone_size_sects);
+
+	dev->zones = kvmalloc_objs(struct nullb_zone, dev->nr_zones,
+				   GFP_KERNEL | __GFP_ZERO);
+	if (!dev->zones)
+		return -ENOMEM;
+
+	spin_lock_init(&dev->zone_res_lock);
+
+	if (dev->zone_nr_conv >= dev->nr_zones) {
+		dev->zone_nr_conv = dev->nr_zones - 1;
+		pr_info("changed the number of conventional zones to %u",
+			dev->zone_nr_conv);
+	}
+
+	dev->zone_append_max_sectors =
+		min(ALIGN_DOWN(dev->zone_append_max_sectors,
+			       dev->blocksize >> SECTOR_SHIFT),
+		    zone_capacity_sects);
+
+	/* Max active zones has to be < nbr of seq zones in order to be enforceable */
+	if (dev->zone_max_active >= dev->nr_zones - dev->zone_nr_conv) {
+		dev->zone_max_active = 0;
+		pr_info("zone_max_active limit disabled, limit >= zone count\n");
+	}
+
+	/* Max open zones has to be <= max active zones */
+	if (dev->zone_max_active && dev->zone_max_open > dev->zone_max_active) {
+		dev->zone_max_open = dev->zone_max_active;
+		pr_info("changed the maximum number of open zones to %u\n",
+			dev->zone_max_open);
+	} else if (dev->zone_max_open >= dev->nr_zones - dev->zone_nr_conv) {
+		dev->zone_max_open = 0;
+		pr_info("zone_max_open limit disabled, limit >= zone count\n");
+	}
+	dev->need_zone_res_mgmt = dev->zone_max_active || dev->zone_max_open;
+	dev->imp_close_zone_no = dev->zone_nr_conv;
+
+	for (i = 0; i <  dev->zone_nr_conv; i++) {
+		zone = &dev->zones[i];
+
+		null_init_zone_lock(dev, zone);
+		zone->start = sector;
+		zone->len = dev->zone_size_sects;
+		zone->capacity = zone->len;
+		zone->wp = zone->start + zone->len;
+		zone->type = BLK_ZONE_TYPE_CONVENTIONAL;
+		zone->cond = BLK_ZONE_COND_NOT_WP;
+
+		sector += dev->zone_size_sects;
+	}
+
+	for (i = dev->zone_nr_conv; i < dev->nr_zones; i++) {
+		zone = &dev->zones[i];
+
+		null_init_zone_lock(dev, zone);
+		zone->start = sector;
+		if (zone->start + dev->zone_size_sects > dev_capacity_sects)
+			zone->len = dev_capacity_sects - zone->start;
+		else
+			zone->len = dev->zone_size_sects;
+		zone->capacity =
+			min_t(sector_t, zone->len, zone_capacity_sects);
+		zone->type = BLK_ZONE_TYPE_SEQWRITE_REQ;
+		if (dev->zone_full) {
+			zone->cond = BLK_ZONE_COND_FULL;
+			zone->wp = zone->start + zone->capacity;
+		} else{
+			zone->cond = BLK_ZONE_COND_EMPTY;
+			zone->wp = zone->start;
+		}
+
+		sector += dev->zone_size_sects;
+	}
+
+	lim->features |= BLK_FEAT_ZONED;
+	lim->chunk_sectors = dev->zone_size_sects;
+	lim->max_hw_zone_append_sectors = dev->zone_append_max_sectors;
+	lim->max_open_zones = dev->zone_max_open;
+	lim->max_active_zones = dev->zone_max_active;
+	return 0;
+}
+
+int null_register_zoned_dev(struct nullb *nullb)
+{
+	struct request_queue *q = nullb->q;
+	struct gendisk *disk = nullb->disk;
+
+	pr_info("%s: using %s zone append\n",
+		disk->disk_name,
+		queue_emulates_zone_append(q) ? "emulated" : "native");
+
+	return blk_revalidate_disk_zones(disk);
+}
+
+void null_free_zoned_dev(struct nullb_device *dev)
+{
+	kvfree(dev->zones);
+	dev->zones = NULL;
+}
+
+int null_report_zones(struct gendisk *disk, sector_t sector,
+		unsigned int nr_zones, struct blk_report_zones_args *args)
+{
+	struct nullb *nullb = disk->private_data;
+	struct nullb_device *dev = nullb->dev;
+	unsigned int first_zone, i;
+	struct nullb_zone *zone;
+	struct blk_zone blkz;
+	int error;
+
+	first_zone = null_zone_no(dev, sector);
+	if (first_zone >= dev->nr_zones)
+		return 0;
+
+	nr_zones = min(nr_zones, dev->nr_zones - first_zone);
+	trace_nullb_report_zones(nullb, nr_zones);
+
+	memset(&blkz, 0, sizeof(struct blk_zone));
+	zone = &dev->zones[first_zone];
+	for (i = 0; i < nr_zones; i++, zone++) {
+		/*
+		 * Stacked DM target drivers will remap the zone information by
+		 * modifying the zone information passed to the report callback.
+		 * So use a local copy to avoid corruption of the device zone
+		 * array.
+		 */
+		null_lock_zone(dev, zone);
+		blkz.start = zone->start;
+		blkz.len = zone->len;
+		blkz.wp = zone->wp;
+		blkz.type = zone->type;
+		blkz.cond = zone->cond;
+		blkz.capacity = zone->capacity;
+		null_unlock_zone(dev, zone);
+
+		error = disk_report_zone(disk, &blkz, i, args);
+		if (error)
+			return error;
+	}
+
+	return nr_zones;
+}
+
+/*
+ * This is called in the case of memory backing from null_process_cmd()
+ * with the target zone already locked.
+ */
+size_t null_zone_valid_read_len(struct nullb *nullb,
+				sector_t sector, unsigned int len)
+{
+	struct nullb_device *dev = nullb->dev;
+	struct nullb_zone *zone = &dev->zones[null_zone_no(dev, sector)];
+	unsigned int nr_sectors = DIV_ROUND_UP(len, SECTOR_SIZE);
+
+	/* Read must be below the write pointer position */
+	if (zone->type == BLK_ZONE_TYPE_CONVENTIONAL ||
+	    sector + nr_sectors <= zone->wp)
+		return len;
+
+	if (sector > zone->wp)
+		return 0;
+
+	return (zone->wp - sector) << SECTOR_SHIFT;
+}
+
+static void null_close_imp_open_zone(struct nullb_device *dev)
+{
+	struct nullb_zone *zone;
+	unsigned int zno, i;
+
+	zno = dev->imp_close_zone_no;
+	if (zno >= dev->nr_zones)
+		zno = dev->zone_nr_conv;
+
+	for (i = dev->zone_nr_conv; i < dev->nr_zones; i++) {
+		zone = &dev->zones[zno];
+		zno++;
+		if (zno >= dev->nr_zones)
+			zno = dev->zone_nr_conv;
+
+		if (zone->cond == BLK_ZONE_COND_IMP_OPEN) {
+			dev->nr_zones_imp_open--;
+			if (zone->wp == zone->start) {
+				zone->cond = BLK_ZONE_COND_EMPTY;
+			} else {
+				zone->cond = BLK_ZONE_COND_CLOSED;
+				dev->nr_zones_closed++;
+			}
+			dev->imp_close_zone_no = zno;
+			return;
+		}
+	}
+}
+
+static blk_status_t null_check_active(struct nullb_device *dev)
+{
+	if (!dev->zone_max_active)
+		return BLK_STS_OK;
+
+	if (dev->nr_zones_exp_open + dev->nr_zones_imp_open +
+			dev->nr_zones_closed < dev->zone_max_active)
+		return BLK_STS_OK;
+
+	return BLK_STS_ZONE_ACTIVE_RESOURCE;
+}
+
+static blk_status_t null_check_open(struct nullb_device *dev)
+{
+	if (!dev->zone_max_open)
+		return BLK_STS_OK;
+
+	if (dev->nr_zones_exp_open + dev->nr_zones_imp_open < dev->zone_max_open)
+		return BLK_STS_OK;
+
+	if (dev->nr_zones_imp_open) {
+		if (null_check_active(dev) == BLK_STS_OK) {
+			null_close_imp_open_zone(dev);
+			return BLK_STS_OK;
+		}
+	}
+
+	return BLK_STS_ZONE_OPEN_RESOURCE;
+}
+
+/*
+ * This function matches the manage open zone resources function in the ZBC standard,
+ * with the addition of max active zones support (added in the ZNS standard).
+ *
+ * The function determines if a zone can transition to implicit open or explicit open,
+ * while maintaining the max open zone (and max active zone) limit(s). It may close an
+ * implicit open zone in order to make additional zone resources available.
+ *
+ * ZBC states that an implicit open zone shall be closed only if there is not
+ * room within the open limit. However, with the addition of an active limit,
+ * it is not certain that closing an implicit open zone will allow a new zone
+ * to be opened, since we might already be at the active limit capacity.
+ */
+static blk_status_t null_check_zone_resources(struct nullb_device *dev,
+					      struct nullb_zone *zone)
+{
+	blk_status_t ret;
+
+	switch (zone->cond) {
+	case BLK_ZONE_COND_EMPTY:
+		ret = null_check_active(dev);
+		if (ret != BLK_STS_OK)
+			return ret;
+		fallthrough;
+	case BLK_ZONE_COND_CLOSED:
+		return null_check_open(dev);
+	default:
+		/* Should never be called for other states */
+		WARN_ON(1);
+		return BLK_STS_IOERR;
+	}
+}
+
+static blk_status_t null_zone_write(struct nullb_cmd *cmd, sector_t sector,
+				    unsigned int nr_sectors, bool append)
+{
+	struct nullb_device *dev = cmd->nq->dev;
+	unsigned int zno = null_zone_no(dev, sector);
+	struct nullb_zone *zone = &dev->zones[zno];
+	blk_status_t badblocks_ret = BLK_STS_OK;
+	blk_status_t ret;
+
+	trace_nullb_zone_op(cmd, zno, zone->cond);
+
+	if (zone->type == BLK_ZONE_TYPE_CONVENTIONAL) {
+		if (append)
+			return BLK_STS_IOERR;
+		return null_process_cmd(cmd, REQ_OP_WRITE, sector, nr_sectors);
+	}
+
+	null_lock_zone(dev, zone);
+
+	/*
+	 * Regular writes must be at the write pointer position. Zone append
+	 * writes are automatically issued at the write pointer and the position
+	 * returned using the request sector. Note that we do not check the zone
+	 * condition because for FULL, READONLY and OFFLINE zones, the sector
+	 * check against the zone write pointer will always result in failing
+	 * the command.
+	 */
+	if (append) {
+		if (WARN_ON_ONCE(!dev->zone_append_max_sectors) ||
+		    zone->wp == NULL_ZONE_INVALID_WP) {
+			ret = BLK_STS_IOERR;
+			goto unlock_zone;
+		}
+		sector = zone->wp;
+		blk_mq_rq_from_pdu(cmd)->__sector = sector;
+	}
+
+	if (sector != zone->wp ||
+	    zone->wp + nr_sectors > zone->start + zone->capacity) {
+		ret = BLK_STS_IOERR;
+		goto unlock_zone;
+	}
+
+	if (zone->cond == BLK_ZONE_COND_CLOSED ||
+	    zone->cond == BLK_ZONE_COND_EMPTY) {
+		if (dev->need_zone_res_mgmt) {
+			spin_lock(&dev->zone_res_lock);
+
+			ret = null_check_zone_resources(dev, zone);
+			if (ret != BLK_STS_OK) {
+				spin_unlock(&dev->zone_res_lock);
+				goto unlock_zone;
+			}
+			if (zone->cond == BLK_ZONE_COND_CLOSED) {
+				dev->nr_zones_closed--;
+				dev->nr_zones_imp_open++;
+			} else if (zone->cond == BLK_ZONE_COND_EMPTY) {
+				dev->nr_zones_imp_open++;
+			}
+
+			spin_unlock(&dev->zone_res_lock);
+		}
+
+		zone->cond = BLK_ZONE_COND_IMP_OPEN;
+	}
+
+	if (dev->badblocks.shift != -1) {
+		badblocks_ret = null_handle_badblocks(cmd, sector, &nr_sectors);
+		if (badblocks_ret != BLK_STS_OK && !nr_sectors) {
+			ret = badblocks_ret;
+			goto unlock_zone;
+		}
+	}
+
+	if (dev->memory_backed) {
+		ret = null_handle_memory_backed(cmd, REQ_OP_WRITE, sector,
+						nr_sectors);
+		if (ret != BLK_STS_OK)
+			goto unlock_zone;
+	}
+
+	zone->wp += nr_sectors;
+	if (zone->wp == zone->start + zone->capacity) {
+		if (dev->need_zone_res_mgmt) {
+			spin_lock(&dev->zone_res_lock);
+			if (zone->cond == BLK_ZONE_COND_EXP_OPEN)
+				dev->nr_zones_exp_open--;
+			else if (zone->cond == BLK_ZONE_COND_IMP_OPEN)
+				dev->nr_zones_imp_open--;
+			spin_unlock(&dev->zone_res_lock);
+		}
+		zone->cond = BLK_ZONE_COND_FULL;
+	}
+
+	ret = badblocks_ret;
+
+unlock_zone:
+	null_unlock_zone(dev, zone);
+
+	return ret;
+}
+
+static blk_status_t null_open_zone(struct nullb_device *dev,
+				   struct nullb_zone *zone)
+{
+	blk_status_t ret = BLK_STS_OK;
+
+	if (zone->type == BLK_ZONE_TYPE_CONVENTIONAL)
+		return BLK_STS_IOERR;
+
+	switch (zone->cond) {
+	case BLK_ZONE_COND_EXP_OPEN:
+		/* Open operation on exp open is not an error */
+		return BLK_STS_OK;
+	case BLK_ZONE_COND_EMPTY:
+	case BLK_ZONE_COND_IMP_OPEN:
+	case BLK_ZONE_COND_CLOSED:
+		break;
+	case BLK_ZONE_COND_FULL:
+	default:
+		return BLK_STS_IOERR;
+	}
+
+	if (dev->need_zone_res_mgmt) {
+		spin_lock(&dev->zone_res_lock);
+
+		switch (zone->cond) {
+		case BLK_ZONE_COND_EMPTY:
+			ret = null_check_zone_resources(dev, zone);
+			if (ret != BLK_STS_OK) {
+				spin_unlock(&dev->zone_res_lock);
+				return ret;
+			}
+			break;
+		case BLK_ZONE_COND_IMP_OPEN:
+			dev->nr_zones_imp_open--;
+			break;
+		case BLK_ZONE_COND_CLOSED:
+			ret = null_check_zone_resources(dev, zone);
+			if (ret != BLK_STS_OK) {
+				spin_unlock(&dev->zone_res_lock);
+				return ret;
+			}
+			dev->nr_zones_closed--;
+			break;
+		default:
+			break;
+		}
+
+		dev->nr_zones_exp_open++;
+
+		spin_unlock(&dev->zone_res_lock);
+	}
+
+	zone->cond = BLK_ZONE_COND_EXP_OPEN;
+
+	return BLK_STS_OK;
+}
+
+static blk_status_t null_close_zone(struct nullb_device *dev,
+				    struct nullb_zone *zone)
+{
+	if (zone->type == BLK_ZONE_TYPE_CONVENTIONAL)
+		return BLK_STS_IOERR;
+
+	switch (zone->cond) {
+	case BLK_ZONE_COND_CLOSED:
+		/* close operation on closed is not an error */
+		return BLK_STS_OK;
+	case BLK_ZONE_COND_IMP_OPEN:
+	case BLK_ZONE_COND_EXP_OPEN:
+		break;
+	case BLK_ZONE_COND_EMPTY:
+	case BLK_ZONE_COND_FULL:
+	default:
+		return BLK_STS_IOERR;
+	}
+
+	if (dev->need_zone_res_mgmt) {
+		spin_lock(&dev->zone_res_lock);
+
+		switch (zone->cond) {
+		case BLK_ZONE_COND_IMP_OPEN:
+			dev->nr_zones_imp_open--;
+			break;
+		case BLK_ZONE_COND_EXP_OPEN:
+			dev->nr_zones_exp_open--;
+			break;
+		default:
+			break;
+		}
+
+		if (zone->wp > zone->start)
+			dev->nr_zones_closed++;
+
+		spin_unlock(&dev->zone_res_lock);
+	}
+
+	if (zone->wp == zone->start)
+		zone->cond = BLK_ZONE_COND_EMPTY;
+	else
+		zone->cond = BLK_ZONE_COND_CLOSED;
+
+	return BLK_STS_OK;
+}
+
+static blk_status_t null_finish_zone(struct nullb_device *dev,
+				     struct nullb_zone *zone)
+{
+	blk_status_t ret = BLK_STS_OK;
+
+	if (zone->type == BLK_ZONE_TYPE_CONVENTIONAL)
+		return BLK_STS_IOERR;
+
+	if (dev->need_zone_res_mgmt) {
+		spin_lock(&dev->zone_res_lock);
+
+		switch (zone->cond) {
+		case BLK_ZONE_COND_FULL:
+			/* Finish operation on full is not an error */
+			spin_unlock(&dev->zone_res_lock);
+			return BLK_STS_OK;
+		case BLK_ZONE_COND_EMPTY:
+			ret = null_check_zone_resources(dev, zone);
+			if (ret != BLK_STS_OK) {
+				spin_unlock(&dev->zone_res_lock);
+				return ret;
+			}
+			break;
+		case BLK_ZONE_COND_IMP_OPEN:
+			dev->nr_zones_imp_open--;
+			break;
+		case BLK_ZONE_COND_EXP_OPEN:
+			dev->nr_zones_exp_open--;
+			break;
+		case BLK_ZONE_COND_CLOSED:
+			ret = null_check_zone_resources(dev, zone);
+			if (ret != BLK_STS_OK) {
+				spin_unlock(&dev->zone_res_lock);
+				return ret;
+			}
+			dev->nr_zones_closed--;
+			break;
+		default:
+			spin_unlock(&dev->zone_res_lock);
+			return BLK_STS_IOERR;
+		}
+
+		spin_unlock(&dev->zone_res_lock);
+	}
+
+	zone->cond = BLK_ZONE_COND_FULL;
+	zone->wp = zone->start + zone->len;
+
+	return BLK_STS_OK;
+}
+
+static blk_status_t null_reset_zone(struct nullb_device *dev,
+				    struct nullb_zone *zone)
+{
+	if (zone->type == BLK_ZONE_TYPE_CONVENTIONAL)
+		return BLK_STS_IOERR;
+
+	if (dev->need_zone_res_mgmt) {
+		spin_lock(&dev->zone_res_lock);
+
+		switch (zone->cond) {
+		case BLK_ZONE_COND_IMP_OPEN:
+			dev->nr_zones_imp_open--;
+			break;
+		case BLK_ZONE_COND_EXP_OPEN:
+			dev->nr_zones_exp_open--;
+			break;
+		case BLK_ZONE_COND_CLOSED:
+			dev->nr_zones_closed--;
+			break;
+		case BLK_ZONE_COND_EMPTY:
+		case BLK_ZONE_COND_FULL:
+			break;
+		default:
+			spin_unlock(&dev->zone_res_lock);
+			return BLK_STS_IOERR;
+		}
+
+		spin_unlock(&dev->zone_res_lock);
+	}
+
+	zone->cond = BLK_ZONE_COND_EMPTY;
+	zone->wp = zone->start;
+
+	if (dev->memory_backed)
+		return null_handle_discard(dev, zone->start, zone->len);
+
+	return BLK_STS_OK;
+}
+
+static blk_status_t null_zone_mgmt(struct nullb_cmd *cmd, enum req_op op,
+				   sector_t sector)
+{
+	struct nullb_device *dev = cmd->nq->dev;
+	unsigned int zone_no;
+	struct nullb_zone *zone;
+	blk_status_t ret;
+	size_t i;
+
+	if (op == REQ_OP_ZONE_RESET_ALL) {
+		for (i = dev->zone_nr_conv; i < dev->nr_zones; i++) {
+			zone = &dev->zones[i];
+			null_lock_zone(dev, zone);
+			if (zone->cond != BLK_ZONE_COND_EMPTY &&
+			    zone->cond != BLK_ZONE_COND_READONLY &&
+			    zone->cond != BLK_ZONE_COND_OFFLINE) {
+				null_reset_zone(dev, zone);
+				trace_nullb_zone_op(cmd, i, zone->cond);
+			}
+			null_unlock_zone(dev, zone);
+		}
+		return BLK_STS_OK;
+	}
+
+	zone_no = null_zone_no(dev, sector);
+	zone = &dev->zones[zone_no];
+
+	null_lock_zone(dev, zone);
+
+	if (zone->cond == BLK_ZONE_COND_READONLY ||
+	    zone->cond == BLK_ZONE_COND_OFFLINE) {
+		ret = BLK_STS_IOERR;
+		goto unlock;
+	}
+
+	switch (op) {
+	case REQ_OP_ZONE_RESET:
+		ret = null_reset_zone(dev, zone);
+		break;
+	case REQ_OP_ZONE_OPEN:
+		ret = null_open_zone(dev, zone);
+		break;
+	case REQ_OP_ZONE_CLOSE:
+		ret = null_close_zone(dev, zone);
+		break;
+	case REQ_OP_ZONE_FINISH:
+		ret = null_finish_zone(dev, zone);
+		break;
+	default:
+		ret = BLK_STS_NOTSUPP;
+		break;
+	}
+
+	if (ret == BLK_STS_OK)
+		trace_nullb_zone_op(cmd, zone_no, zone->cond);
+
+unlock:
+	null_unlock_zone(dev, zone);
+
+	return ret;
+}
+
+blk_status_t null_process_zoned_cmd(struct nullb_cmd *cmd, enum req_op op,
+				    sector_t sector, sector_t nr_sectors)
+{
+	struct nullb_device *dev;
+	struct nullb_zone *zone;
+	blk_status_t sts;
+
+	switch (op) {
+	case REQ_OP_WRITE:
+		return null_zone_write(cmd, sector, nr_sectors, false);
+	case REQ_OP_ZONE_APPEND:
+		return null_zone_write(cmd, sector, nr_sectors, true);
+	case REQ_OP_ZONE_RESET:
+	case REQ_OP_ZONE_RESET_ALL:
+	case REQ_OP_ZONE_OPEN:
+	case REQ_OP_ZONE_CLOSE:
+	case REQ_OP_ZONE_FINISH:
+		return null_zone_mgmt(cmd, op, sector);
+	default:
+		dev = cmd->nq->dev;
+		zone = &dev->zones[null_zone_no(dev, sector)];
+		if (zone->cond == BLK_ZONE_COND_OFFLINE)
+			return BLK_STS_IOERR;
+
+		null_lock_zone(dev, zone);
+		sts = null_process_cmd(cmd, op, sector, nr_sectors);
+		null_unlock_zone(dev, zone);
+		return sts;
+	}
+}
+
+/*
+ * Set a zone in the read-only or offline condition.
+ */
+static void null_set_zone_cond(struct nullb_device *dev,
+			       struct nullb_zone *zone, enum blk_zone_cond cond)
+{
+	if (WARN_ON_ONCE(cond != BLK_ZONE_COND_READONLY &&
+			 cond != BLK_ZONE_COND_OFFLINE))
+		return;
+
+	null_lock_zone(dev, zone);
+
+	/*
+	 * If the read-only condition is requested again to zones already in
+	 * read-only condition, restore back normal empty condition. Do the same
+	 * if the offline condition is requested for offline zones. Otherwise,
+	 * set the specified zone condition to the zones. Finish the zones
+	 * beforehand to free up zone resources.
+	 */
+	if (zone->cond == cond) {
+		zone->cond = BLK_ZONE_COND_EMPTY;
+		zone->wp = zone->start;
+		if (dev->memory_backed)
+			null_handle_discard(dev, zone->start, zone->len);
+	} else {
+		if (zone->cond != BLK_ZONE_COND_READONLY &&
+		    zone->cond != BLK_ZONE_COND_OFFLINE)
+			null_finish_zone(dev, zone);
+		zone->cond = cond;
+		zone->wp = NULL_ZONE_INVALID_WP;
+	}
+
+	null_unlock_zone(dev, zone);
+}
+
+/*
+ * Identify a zone from the sector written to configfs file. Then set zone
+ * condition to the zone.
+ */
+ssize_t zone_cond_store(struct nullb_device *dev, const char *page,
+			size_t count, enum blk_zone_cond cond)
+{
+	unsigned long long sector;
+	unsigned int zone_no;
+	int ret;
+
+	if (!dev->zoned) {
+		pr_err("null_blk device is not zoned\n");
+		return -EINVAL;
+	}
+
+	if (!dev->zones) {
+		pr_err("null_blk device is not yet powered\n");
+		return -EINVAL;
+	}
+
+	ret = kstrtoull(page, 0, &sector);
+	if (ret < 0)
+		return ret;
+
+	zone_no = null_zone_no(dev, sector);
+	if (zone_no >= dev->nr_zones) {
+		pr_err("Sector out of range\n");
+		return -EINVAL;
+	}
+
+	if (dev->zones[zone_no].type == BLK_ZONE_TYPE_CONVENTIONAL) {
+		pr_err("Can not change condition of conventional zones\n");
+		return -EINVAL;
+	}
+
+	null_set_zone_cond(dev, &dev->zones[zone_no], cond);
+
+	return count;
+}