// SPDX-License-Identifier: GPL-2.0

  /*
   * Zoned block device handling
   *
   * Copyright (c) 2015, Hannes Reinecke
   * Copyright (c) 2015, SUSE Linux GmbH
   *
   * Copyright (c) 2016, Damien Le Moal
   * Copyright (c) 2016, Western Digital
   */
  
  #include <linux/kernel.h>
  #include <linux/module.h>
  #include <linux/rbtree.h>
  #include <linux/blkdev.h>

  #include <linux/blk-mq.h>

  #include <linux/mm.h>
  #include <linux/vmalloc.h>

  #include <linux/sched/mm.h>

  #include "blk.h"

  #define ZONE_COND_NAME(name) [BLK_ZONE_COND_##name] = #name
  static const char *const zone_cond_name[] = {
  	ZONE_COND_NAME(NOT_WP),
  	ZONE_COND_NAME(EMPTY),
  	ZONE_COND_NAME(IMP_OPEN),
  	ZONE_COND_NAME(EXP_OPEN),
  	ZONE_COND_NAME(CLOSED),
  	ZONE_COND_NAME(READONLY),
  	ZONE_COND_NAME(FULL),
  	ZONE_COND_NAME(OFFLINE),
  };
  #undef ZONE_COND_NAME
  
  /**
   * blk_zone_cond_str - Return string XXX in BLK_ZONE_COND_XXX.
   * @zone_cond: BLK_ZONE_COND_XXX.
   *
   * Description: Centralize block layer function to convert BLK_ZONE_COND_XXX
   * into string format. Useful in the debugging and tracing zone conditions. For
   * invalid BLK_ZONE_COND_XXX it returns string "UNKNOWN".
   */
  const char *blk_zone_cond_str(enum blk_zone_cond zone_cond)
  {
  	static const char *zone_cond_str = "UNKNOWN";
  
  	if (zone_cond < ARRAY_SIZE(zone_cond_name) && zone_cond_name[zone_cond])
  		zone_cond_str = zone_cond_name[zone_cond];
  
  	return zone_cond_str;
  }
  EXPORT_SYMBOL_GPL(blk_zone_cond_str);

  static inline sector_t blk_zone_start(struct request_queue *q,
  				      sector_t sector)
  {

  	sector_t zone_mask = blk_queue_zone_sectors(q) - 1;

  
  	return sector & ~zone_mask;
  }
  
  /*

   * Return true if a request is a write requests that needs zone write locking.
   */
  bool blk_req_needs_zone_write_lock(struct request *rq)
  {
  	if (!rq->q->seq_zones_wlock)
  		return false;
  
  	if (blk_rq_is_passthrough(rq))
  		return false;
  
  	switch (req_op(rq)) {
  	case REQ_OP_WRITE_ZEROES:
  	case REQ_OP_WRITE_SAME:
  	case REQ_OP_WRITE:
  		return blk_rq_zone_is_seq(rq);
  	default:
  		return false;
  	}
  }
  EXPORT_SYMBOL_GPL(blk_req_needs_zone_write_lock);

  bool blk_req_zone_write_trylock(struct request *rq)
  {
  	unsigned int zno = blk_rq_zone_no(rq);
  
  	if (test_and_set_bit(zno, rq->q->seq_zones_wlock))
  		return false;
  
  	WARN_ON_ONCE(rq->rq_flags & RQF_ZONE_WRITE_LOCKED);
  	rq->rq_flags |= RQF_ZONE_WRITE_LOCKED;
  
  	return true;
  }
  EXPORT_SYMBOL_GPL(blk_req_zone_write_trylock);

  void __blk_req_zone_write_lock(struct request *rq)
  {
  	if (WARN_ON_ONCE(test_and_set_bit(blk_rq_zone_no(rq),
  					  rq->q->seq_zones_wlock)))
  		return;
  
  	WARN_ON_ONCE(rq->rq_flags & RQF_ZONE_WRITE_LOCKED);
  	rq->rq_flags |= RQF_ZONE_WRITE_LOCKED;
  }
  EXPORT_SYMBOL_GPL(__blk_req_zone_write_lock);
  
  void __blk_req_zone_write_unlock(struct request *rq)
  {
  	rq->rq_flags &= ~RQF_ZONE_WRITE_LOCKED;
  	if (rq->q->seq_zones_wlock)
  		WARN_ON_ONCE(!test_and_clear_bit(blk_rq_zone_no(rq),
  						 rq->q->seq_zones_wlock));
  }
  EXPORT_SYMBOL_GPL(__blk_req_zone_write_unlock);

  /**
   * blkdev_nr_zones - Get number of zones

   * @disk:	Target gendisk

   *

   * Return the total number of zones of a zoned block device.  For a block
   * device without zone capabilities, the number of zones is always 0.

   */

  unsigned int blkdev_nr_zones(struct gendisk *disk)

  {

  	sector_t zone_sectors = blk_queue_zone_sectors(disk->queue);

  	if (!blk_queue_is_zoned(disk->queue))

  		return 0;

  	return (get_capacity(disk) + zone_sectors - 1) >> ilog2(zone_sectors);

  }
  EXPORT_SYMBOL_GPL(blkdev_nr_zones);

  /**
   * blkdev_report_zones - Get zones information
   * @bdev:	Target block device
   * @sector:	Sector from which to report zones

   * @nr_zones:	Maximum number of zones to report
   * @cb:		Callback function called for each reported zone
   * @data:	Private data for the callback

   *
   * Description:

   *    Get zone information starting from the zone containing @sector for at most
   *    @nr_zones, and call @cb for each zone reported by the device.
   *    To report all zones in a device starting from @sector, the BLK_ALL_ZONES
   *    constant can be passed to @nr_zones.
   *    Returns the number of zones reported by the device, or a negative errno
   *    value in case of failure.
   *
   *    Note: The caller must use memalloc_noXX_save/restore() calls to control
   *    memory allocations done within this function.

   */

  int blkdev_report_zones(struct block_device *bdev, sector_t sector,

  			unsigned int nr_zones, report_zones_cb cb, void *data)

  {

  	struct gendisk *disk = bdev->bd_disk;

  	sector_t capacity = get_capacity(disk);

  	if (!blk_queue_is_zoned(bdev_get_queue(bdev)) ||
  	    WARN_ON_ONCE(!disk->fops->report_zones))

  		return -EOPNOTSUPP;

  	if (!nr_zones || sector >= capacity)

  		return 0;

  	return disk->fops->report_zones(disk, sector, nr_zones, cb, data);

  }
  EXPORT_SYMBOL_GPL(blkdev_report_zones);

  static inline bool blkdev_allow_reset_all_zones(struct block_device *bdev,

  						sector_t sector,

  						sector_t nr_sectors)
  {
  	if (!blk_queue_zone_resetall(bdev_get_queue(bdev)))
  		return false;

  	/*

  	 * REQ_OP_ZONE_RESET_ALL can be executed only if the number of sectors
  	 * of the applicable zone range is the entire disk.

  	 */

  	return !sector && nr_sectors == get_capacity(bdev->bd_disk);

  }

  /**

   * blkdev_zone_mgmt - Execute a zone management operation on a range of zones

   * @bdev:	Target block device

   * @op:		Operation to be performed on the zones
   * @sector:	Start sector of the first zone to operate on
   * @nr_sectors:	Number of sectors, should be at least the length of one zone and
   *		must be zone size aligned.

   * @gfp_mask:	Memory allocation flags (for bio_alloc)
   *
   * Description:

   *    Perform the specified operation on the range of zones specified by

   *    @sector..@sector+@nr_sectors. Specifying the entire disk sector range
   *    is valid, but the specified range should not contain conventional zones.

   *    The operation to execute on each zone can be a zone reset, open, close
   *    or finish request.

   */

  int blkdev_zone_mgmt(struct block_device *bdev, enum req_opf op,
  		     sector_t sector, sector_t nr_sectors,
  		     gfp_t gfp_mask)

  {
  	struct request_queue *q = bdev_get_queue(bdev);

  	sector_t zone_sectors = blk_queue_zone_sectors(q);

  	sector_t capacity = get_capacity(bdev->bd_disk);

  	sector_t end_sector = sector + nr_sectors;

  	struct bio *bio = NULL;

  	int ret;

  	if (!blk_queue_is_zoned(q))
  		return -EOPNOTSUPP;

  	if (bdev_read_only(bdev))
  		return -EPERM;

  	if (!op_is_zone_mgmt(op))
  		return -EOPNOTSUPP;

  	if (end_sector <= sector || end_sector > capacity)

  		/* Out of range */
  		return -EINVAL;
  
  	/* Check alignment (handle eventual smaller last zone) */

  	if (sector & (zone_sectors - 1))
  		return -EINVAL;

  	if ((nr_sectors & (zone_sectors - 1)) && end_sector != capacity)

  		return -EINVAL;
  
  	while (sector < end_sector) {

  		bio = blk_next_bio(bio, 0, gfp_mask);

  		bio_set_dev(bio, bdev);

  		/*
  		 * Special case for the zone reset operation that reset all
  		 * zones, this is useful for applications like mkfs.
  		 */

  		if (op == REQ_OP_ZONE_RESET &&
  		    blkdev_allow_reset_all_zones(bdev, sector, nr_sectors)) {

  			bio->bi_opf = REQ_OP_ZONE_RESET_ALL;
  			break;
  		}

  		bio->bi_opf = op | REQ_SYNC;

  		bio->bi_iter.bi_sector = sector;

  		sector += zone_sectors;
  
  		/* This may take a while, so be nice to others */
  		cond_resched();

  	}

  	ret = submit_bio_wait(bio);
  	bio_put(bio);

  	return ret;

  }

  EXPORT_SYMBOL_GPL(blkdev_zone_mgmt);

  struct zone_report_args {
  	struct blk_zone __user *zones;
  };
  
  static int blkdev_copy_zone_to_user(struct blk_zone *zone, unsigned int idx,
  				    void *data)
  {
  	struct zone_report_args *args = data;
  
  	if (copy_to_user(&args->zones[idx], zone, sizeof(struct blk_zone)))
  		return -EFAULT;
  	return 0;
  }

  /*

   * BLKREPORTZONE ioctl processing.
   * Called from blkdev_ioctl.
   */
  int blkdev_report_zones_ioctl(struct block_device *bdev, fmode_t mode,
  			      unsigned int cmd, unsigned long arg)
  {
  	void __user *argp = (void __user *)arg;

  	struct zone_report_args args;

  	struct request_queue *q;
  	struct blk_zone_report rep;

  	int ret;
  
  	if (!argp)
  		return -EINVAL;
  
  	q = bdev_get_queue(bdev);
  	if (!q)
  		return -ENXIO;
  
  	if (!blk_queue_is_zoned(q))
  		return -ENOTTY;
  
  	if (!capable(CAP_SYS_ADMIN))
  		return -EACCES;
  
  	if (copy_from_user(&rep, argp, sizeof(struct blk_zone_report)))
  		return -EFAULT;
  
  	if (!rep.nr_zones)
  		return -EINVAL;

  	args.zones = argp + sizeof(struct blk_zone_report);
  	ret = blkdev_report_zones(bdev, rep.sector, rep.nr_zones,
  				  blkdev_copy_zone_to_user, &args);
  	if (ret < 0)
  		return ret;

  	rep.nr_zones = ret;

  	rep.flags = BLK_ZONE_REP_CAPACITY;

  	if (copy_to_user(argp, &rep, sizeof(struct blk_zone_report)))
  		return -EFAULT;
  	return 0;

  }

  /*

   * BLKRESETZONE, BLKOPENZONE, BLKCLOSEZONE and BLKFINISHZONE ioctl processing.

   * Called from blkdev_ioctl.
   */

  int blkdev_zone_mgmt_ioctl(struct block_device *bdev, fmode_t mode,
  			   unsigned int cmd, unsigned long arg)

  {
  	void __user *argp = (void __user *)arg;
  	struct request_queue *q;
  	struct blk_zone_range zrange;

  	enum req_opf op;

  
  	if (!argp)
  		return -EINVAL;
  
  	q = bdev_get_queue(bdev);
  	if (!q)
  		return -ENXIO;
  
  	if (!blk_queue_is_zoned(q))
  		return -ENOTTY;
  
  	if (!capable(CAP_SYS_ADMIN))
  		return -EACCES;
  
  	if (!(mode & FMODE_WRITE))
  		return -EBADF;
  
  	if (copy_from_user(&zrange, argp, sizeof(struct blk_zone_range)))
  		return -EFAULT;

  	switch (cmd) {
  	case BLKRESETZONE:
  		op = REQ_OP_ZONE_RESET;
  		break;
  	case BLKOPENZONE:
  		op = REQ_OP_ZONE_OPEN;
  		break;
  	case BLKCLOSEZONE:
  		op = REQ_OP_ZONE_CLOSE;
  		break;
  	case BLKFINISHZONE:
  		op = REQ_OP_ZONE_FINISH;
  		break;
  	default:
  		return -ENOTTY;
  	}
  
  	return blkdev_zone_mgmt(bdev, op, zrange.sector, zrange.nr_sectors,
  				GFP_KERNEL);

  }

  
  static inline unsigned long *blk_alloc_zone_bitmap(int node,
  						   unsigned int nr_zones)
  {
  	return kcalloc_node(BITS_TO_LONGS(nr_zones), sizeof(unsigned long),
  			    GFP_NOIO, node);
  }

  void blk_queue_free_zone_bitmaps(struct request_queue *q)
  {

  	kfree(q->conv_zones_bitmap);
  	q->conv_zones_bitmap = NULL;

  	kfree(q->seq_zones_wlock);
  	q->seq_zones_wlock = NULL;
  }

  struct blk_revalidate_zone_args {
  	struct gendisk	*disk;

  	unsigned long	*conv_zones_bitmap;

  	unsigned long	*seq_zones_wlock;

  	unsigned int	nr_zones;

  	sector_t	zone_sectors;

  	sector_t	sector;
  };

  /*
   * Helper function to check the validity of zones of a zoned block device.
   */

  static int blk_revalidate_zone_cb(struct blk_zone *zone, unsigned int idx,
  				  void *data)

  {

  	struct blk_revalidate_zone_args *args = data;
  	struct gendisk *disk = args->disk;

  	struct request_queue *q = disk->queue;

  	sector_t capacity = get_capacity(disk);
  
  	/*
  	 * All zones must have the same size, with the exception on an eventual
  	 * smaller last zone.
  	 */

  	if (zone->start == 0) {
  		if (zone->len == 0 || !is_power_of_2(zone->len)) {
  			pr_warn("%s: Invalid zoned device with non power of two zone size (%llu)
  ",
  				disk->disk_name, zone->len);
  			return -ENODEV;
  		}

  		args->zone_sectors = zone->len;
  		args->nr_zones = (capacity + zone->len - 1) >> ilog2(zone->len);
  	} else if (zone->start + args->zone_sectors < capacity) {
  		if (zone->len != args->zone_sectors) {
  			pr_warn("%s: Invalid zoned device with non constant zone size
  ",
  				disk->disk_name);
  			return -ENODEV;
  		}
  	} else {
  		if (zone->len > args->zone_sectors) {
  			pr_warn("%s: Invalid zoned device with larger last zone size
  ",
  				disk->disk_name);
  			return -ENODEV;
  		}

  	}
  
  	/* Check for holes in the zone report */

  	if (zone->start != args->sector) {

  		pr_warn("%s: Zone gap at sectors %llu..%llu
  ",

  			disk->disk_name, args->sector, zone->start);
  		return -ENODEV;

  	}
  
  	/* Check zone type */
  	switch (zone->type) {
  	case BLK_ZONE_TYPE_CONVENTIONAL:

  		if (!args->conv_zones_bitmap) {
  			args->conv_zones_bitmap =
  				blk_alloc_zone_bitmap(q->node, args->nr_zones);
  			if (!args->conv_zones_bitmap)
  				return -ENOMEM;
  		}
  		set_bit(idx, args->conv_zones_bitmap);
  		break;

  	case BLK_ZONE_TYPE_SEQWRITE_REQ:
  	case BLK_ZONE_TYPE_SEQWRITE_PREF:

  		if (!args->seq_zones_wlock) {
  			args->seq_zones_wlock =
  				blk_alloc_zone_bitmap(q->node, args->nr_zones);
  			if (!args->seq_zones_wlock)
  				return -ENOMEM;
  		}

  		break;
  	default:
  		pr_warn("%s: Invalid zone type 0x%x at sectors %llu
  ",
  			disk->disk_name, (int)zone->type, zone->start);

  		return -ENODEV;

  	}

  	args->sector += zone->len;
  	return 0;
  }

  /**
   * blk_revalidate_disk_zones - (re)allocate and initialize zone bitmaps
   * @disk:	Target disk

   * @update_driver_data:	Callback to update driver data on the frozen disk

   *
   * Helper function for low-level device drivers to (re) allocate and initialize
   * a disk request queue zone bitmaps. This functions should normally be called

   * within the disk ->revalidate method for blk-mq based drivers.  For BIO based
   * drivers only q->nr_zones needs to be updated so that the sysfs exposed value
   * is correct.

   * If the @update_driver_data callback function is not NULL, the callback is
   * executed with the device request queue frozen after all zones have been
   * checked.

   */

  int blk_revalidate_disk_zones(struct gendisk *disk,
  			      void (*update_driver_data)(struct gendisk *disk))

  {
  	struct request_queue *q = disk->queue;

  	struct blk_revalidate_zone_args args = {
  		.disk		= disk,

  	};

  	unsigned int noio_flag;
  	int ret;

  	if (WARN_ON_ONCE(!blk_queue_is_zoned(q)))
  		return -EIO;

  	if (WARN_ON_ONCE(!queue_is_mq(q)))
  		return -EIO;

  	if (!get_capacity(disk))
  		return -EIO;

  	/*

  	 * Ensure that all memory allocations in this context are done as if
  	 * GFP_NOIO was specified.

  	 */

  	noio_flag = memalloc_noio_save();
  	ret = disk->fops->report_zones(disk, 0, UINT_MAX,
  				       blk_revalidate_zone_cb, &args);
  	memalloc_noio_restore(noio_flag);

  	/*

  	 * Install the new bitmaps and update nr_zones only once the queue is
  	 * stopped and all I/Os are completed (i.e. a scheduler is not
  	 * referencing the bitmaps).

  	 */
  	blk_mq_freeze_queue(q);

  	if (ret >= 0) {

  		blk_queue_chunk_sectors(q, args.zone_sectors);

  		q->nr_zones = args.nr_zones;

  		swap(q->seq_zones_wlock, args.seq_zones_wlock);

  		swap(q->conv_zones_bitmap, args.conv_zones_bitmap);

  		if (update_driver_data)
  			update_driver_data(disk);

  		ret = 0;
  	} else {

  		pr_warn("%s: failed to revalidate zones
  ", disk->disk_name);

  		blk_queue_free_zone_bitmaps(q);

  	}

  	blk_mq_unfreeze_queue(q);

  	kfree(args.seq_zones_wlock);

  	kfree(args.conv_zones_bitmap);

  	return ret;
  }
  EXPORT_SYMBOL_GPL(blk_revalidate_disk_zones);