/* 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 */