// SPDX-License-Identifier: GPL-2.0

  /*
   *  Code extracted from drivers/block/genhd.c
   *  Copyright (C) 1991-1998  Linus Torvalds
   *  Re-organised Feb 1998 Russell King
   *
   *  We now have independent partition support from the
   *  block drivers, which allows all the partition code to
   *  be grouped in one location, and it to be mostly self
   *  contained.
   */
  
  #include <linux/init.h>
  #include <linux/module.h>
  #include <linux/fs.h>
  #include <linux/slab.h>
  #include <linux/kmod.h>
  #include <linux/ctype.h>
  #include <linux/genhd.h>
  #include <linux/blktrace_api.h>
  
  #include "partitions/check.h"
  
  #ifdef CONFIG_BLK_DEV_MD
  extern void md_autodetect_dev(dev_t dev);
  #endif
   
  /*
   * disk_name() is used by partition check code and the genhd driver.
   * It formats the devicename of the indicated disk into
   * the supplied buffer (of size at least 32), and returns
   * a pointer to that same buffer (for convenience).
   */
  
  char *disk_name(struct gendisk *hd, int partno, char *buf)
  {
  	if (!partno)
  		snprintf(buf, BDEVNAME_SIZE, "%s", hd->disk_name);
  	else if (isdigit(hd->disk_name[strlen(hd->disk_name)-1]))
  		snprintf(buf, BDEVNAME_SIZE, "%sp%d", hd->disk_name, partno);
  	else
  		snprintf(buf, BDEVNAME_SIZE, "%s%d", hd->disk_name, partno);
  
  	return buf;
  }
  
  const char *bdevname(struct block_device *bdev, char *buf)
  {
  	return disk_name(bdev->bd_disk, bdev->bd_part->partno, buf);
  }
  
  EXPORT_SYMBOL(bdevname);

  const char *bio_devname(struct bio *bio, char *buf)
  {
  	return disk_name(bio->bi_disk, bio->bi_partno, buf);
  }
  EXPORT_SYMBOL(bio_devname);

  /*
   * There's very little reason to use this, you should really
   * have a struct block_device just about everywhere and use
   * bdevname() instead.
   */
  const char *__bdevname(dev_t dev, char *buffer)
  {
  	scnprintf(buffer, BDEVNAME_SIZE, "unknown-block(%u,%u)",
  				MAJOR(dev), MINOR(dev));
  	return buffer;
  }
  
  EXPORT_SYMBOL(__bdevname);
  
  static ssize_t part_partition_show(struct device *dev,
  				   struct device_attribute *attr, char *buf)
  {
  	struct hd_struct *p = dev_to_part(dev);
  
  	return sprintf(buf, "%d
  ", p->partno);
  }
  
  static ssize_t part_start_show(struct device *dev,
  			       struct device_attribute *attr, char *buf)
  {
  	struct hd_struct *p = dev_to_part(dev);
  
  	return sprintf(buf, "%llu
  ",(unsigned long long)p->start_sect);
  }
  
  ssize_t part_size_show(struct device *dev,
  		       struct device_attribute *attr, char *buf)
  {
  	struct hd_struct *p = dev_to_part(dev);

  	return sprintf(buf, "%llu
  ",(unsigned long long)part_nr_sects_read(p));

  }
  
  static ssize_t part_ro_show(struct device *dev,
  			    struct device_attribute *attr, char *buf)
  {
  	struct hd_struct *p = dev_to_part(dev);
  	return sprintf(buf, "%d
  ", p->policy ? 1 : 0);
  }
  
  static ssize_t part_alignment_offset_show(struct device *dev,
  					  struct device_attribute *attr, char *buf)
  {
  	struct hd_struct *p = dev_to_part(dev);
  	return sprintf(buf, "%llu
  ", (unsigned long long)p->alignment_offset);
  }
  
  static ssize_t part_discard_alignment_show(struct device *dev,
  					   struct device_attribute *attr, char *buf)
  {
  	struct hd_struct *p = dev_to_part(dev);
  	return sprintf(buf, "%u
  ", p->discard_alignment);
  }
  
  ssize_t part_stat_show(struct device *dev,
  		       struct device_attribute *attr, char *buf)
  {
  	struct hd_struct *p = dev_to_part(dev);

  	struct request_queue *q = part_to_disk(p)->queue;

  	unsigned int inflight;

  	inflight = part_in_flight(q, p);

  	return sprintf(buf,
  		"%8lu %8lu %8llu %8u "
  		"%8lu %8lu %8llu %8u "

  		"%8u %8u %8u "
  		"%8lu %8lu %8llu %8u"

  		"
  ",

  		part_stat_read(p, ios[STAT_READ]),
  		part_stat_read(p, merges[STAT_READ]),
  		(unsigned long long)part_stat_read(p, sectors[STAT_READ]),

  		(unsigned int)part_stat_read_msecs(p, STAT_READ),

  		part_stat_read(p, ios[STAT_WRITE]),
  		part_stat_read(p, merges[STAT_WRITE]),
  		(unsigned long long)part_stat_read(p, sectors[STAT_WRITE]),

  		(unsigned int)part_stat_read_msecs(p, STAT_WRITE),

  		inflight,

  		jiffies_to_msecs(part_stat_read(p, io_ticks)),

  		jiffies_to_msecs(part_stat_read(p, time_in_queue)),
  		part_stat_read(p, ios[STAT_DISCARD]),
  		part_stat_read(p, merges[STAT_DISCARD]),
  		(unsigned long long)part_stat_read(p, sectors[STAT_DISCARD]),

  		(unsigned int)part_stat_read_msecs(p, STAT_DISCARD));

  }

  ssize_t part_inflight_show(struct device *dev, struct device_attribute *attr,
  			   char *buf)

  {
  	struct hd_struct *p = dev_to_part(dev);

  	struct request_queue *q = part_to_disk(p)->queue;
  	unsigned int inflight[2];

  	part_in_flight_rw(q, p, inflight);
  	return sprintf(buf, "%8u %8u
  ", inflight[0], inflight[1]);

  }
  
  #ifdef CONFIG_FAIL_MAKE_REQUEST
  ssize_t part_fail_show(struct device *dev,
  		       struct device_attribute *attr, char *buf)
  {
  	struct hd_struct *p = dev_to_part(dev);
  
  	return sprintf(buf, "%d
  ", p->make_it_fail);
  }
  
  ssize_t part_fail_store(struct device *dev,
  			struct device_attribute *attr,
  			const char *buf, size_t count)
  {
  	struct hd_struct *p = dev_to_part(dev);
  	int i;
  
  	if (count > 0 && sscanf(buf, "%d", &i) > 0)
  		p->make_it_fail = (i == 0) ? 0 : 1;
  
  	return count;
  }
  #endif

  static DEVICE_ATTR(partition, 0444, part_partition_show, NULL);
  static DEVICE_ATTR(start, 0444, part_start_show, NULL);
  static DEVICE_ATTR(size, 0444, part_size_show, NULL);
  static DEVICE_ATTR(ro, 0444, part_ro_show, NULL);
  static DEVICE_ATTR(alignment_offset, 0444, part_alignment_offset_show, NULL);
  static DEVICE_ATTR(discard_alignment, 0444, part_discard_alignment_show, NULL);
  static DEVICE_ATTR(stat, 0444, part_stat_show, NULL);
  static DEVICE_ATTR(inflight, 0444, part_inflight_show, NULL);

  #ifdef CONFIG_FAIL_MAKE_REQUEST
  static struct device_attribute dev_attr_fail =

  	__ATTR(make-it-fail, 0644, part_fail_show, part_fail_store);

  #endif
  
  static struct attribute *part_attrs[] = {
  	&dev_attr_partition.attr,
  	&dev_attr_start.attr,
  	&dev_attr_size.attr,
  	&dev_attr_ro.attr,
  	&dev_attr_alignment_offset.attr,
  	&dev_attr_discard_alignment.attr,
  	&dev_attr_stat.attr,
  	&dev_attr_inflight.attr,
  #ifdef CONFIG_FAIL_MAKE_REQUEST
  	&dev_attr_fail.attr,
  #endif
  	NULL
  };
  
  static struct attribute_group part_attr_group = {
  	.attrs = part_attrs,
  };
  
  static const struct attribute_group *part_attr_groups[] = {
  	&part_attr_group,
  #ifdef CONFIG_BLK_DEV_IO_TRACE
  	&blk_trace_attr_group,
  #endif
  	NULL
  };
  
  static void part_release(struct device *dev)
  {
  	struct hd_struct *p = dev_to_part(dev);

  	blk_free_devt(dev->devt);

  	hd_free_part(p);

  	kfree(p);
  }

  static int part_uevent(struct device *dev, struct kobj_uevent_env *env)
  {
  	struct hd_struct *part = dev_to_part(dev);
  
  	add_uevent_var(env, "PARTN=%u", part->partno);
  	if (part->info && part->info->volname[0])
  		add_uevent_var(env, "PARTNAME=%s", part->info->volname);
  	return 0;
  }

  struct device_type part_type = {
  	.name		= "partition",
  	.groups		= part_attr_groups,
  	.release	= part_release,

  	.uevent		= part_uevent,

  };

  static void delete_partition_work_fn(struct work_struct *work)

  {

  	struct hd_struct *part = container_of(to_rcu_work(work), struct hd_struct,
  					rcu_work);

  
  	part->start_sect = 0;
  	part->nr_sects = 0;
  	part_stat_set_all(part, 0);
  	put_device(part_to_dev(part));
  }

  void __delete_partition(struct percpu_ref *ref)

  {

  	struct hd_struct *part = container_of(ref, struct hd_struct, ref);

  	INIT_RCU_WORK(&part->rcu_work, delete_partition_work_fn);
  	queue_rcu_work(system_wq, &part->rcu_work);

  }

  /*
   * Must be called either with bd_mutex held, before a disk can be opened or
   * after all disk users are gone.
   */

  void delete_partition(struct gendisk *disk, int partno)
  {

  	struct disk_part_tbl *ptbl =
  		rcu_dereference_protected(disk->part_tbl, 1);

  	struct hd_struct *part;
  
  	if (partno >= ptbl->len)
  		return;

  	part = rcu_dereference_protected(ptbl->part[partno], 1);

  	if (!part)
  		return;

  	rcu_assign_pointer(ptbl->part[partno], NULL);
  	rcu_assign_pointer(ptbl->last_lookup, NULL);
  	kobject_put(part->holder_dir);
  	device_del(part_to_dev(part));

  	/*
  	 * Remove gendisk pointer from idr so that it cannot be looked up
  	 * while RCU period before freeing gendisk is running to prevent
  	 * use-after-free issues. Note that the device number stays
  	 * "in-use" until we really free the gendisk.
  	 */
  	blk_invalidate_devt(part_devt(part));

  	hd_struct_kill(part);

  }
  
  static ssize_t whole_disk_show(struct device *dev,
  			       struct device_attribute *attr, char *buf)
  {
  	return 0;
  }

  static DEVICE_ATTR(whole_disk, 0444, whole_disk_show, NULL);

  /*
   * Must be called either with bd_mutex held, before a disk can be opened or
   * after all disk users are gone.
   */

  struct hd_struct *add_partition(struct gendisk *disk, int partno,
  				sector_t start, sector_t len, int flags,
  				struct partition_meta_info *info)
  {
  	struct hd_struct *p;
  	dev_t devt = MKDEV(0, 0);
  	struct device *ddev = disk_to_dev(disk);
  	struct device *pdev;
  	struct disk_part_tbl *ptbl;
  	const char *dname;
  	int err;
  
  	err = disk_expand_part_tbl(disk, partno);
  	if (err)
  		return ERR_PTR(err);

  	ptbl = rcu_dereference_protected(disk->part_tbl, 1);

  
  	if (ptbl->part[partno])
  		return ERR_PTR(-EBUSY);
  
  	p = kzalloc(sizeof(*p), GFP_KERNEL);
  	if (!p)
  		return ERR_PTR(-EBUSY);
  
  	if (!init_part_stats(p)) {
  		err = -ENOMEM;
  		goto out_free;
  	}

  
  	seqcount_init(&p->nr_sects_seq);

  	pdev = part_to_dev(p);
  
  	p->start_sect = start;
  	p->alignment_offset =
  		queue_limit_alignment_offset(&disk->queue->limits, start);
  	p->discard_alignment =
  		queue_limit_discard_alignment(&disk->queue->limits, start);
  	p->nr_sects = len;
  	p->partno = partno;
  	p->policy = get_disk_ro(disk);
  
  	if (info) {
  		struct partition_meta_info *pinfo = alloc_part_info(disk);

  		if (!pinfo) {
  			err = -ENOMEM;

  			goto out_free_stats;

  		}

  		memcpy(pinfo, info, sizeof(*info));
  		p->info = pinfo;
  	}
  
  	dname = dev_name(ddev);
  	if (isdigit(dname[strlen(dname) - 1]))
  		dev_set_name(pdev, "%sp%d", dname, partno);
  	else
  		dev_set_name(pdev, "%s%d", dname, partno);
  
  	device_initialize(pdev);
  	pdev->class = &block_class;
  	pdev->type = &part_type;
  	pdev->parent = ddev;
  
  	err = blk_alloc_devt(p, &devt);
  	if (err)
  		goto out_free_info;
  	pdev->devt = devt;
  
  	/* delay uevent until 'holders' subdir is created */
  	dev_set_uevent_suppress(pdev, 1);
  	err = device_add(pdev);
  	if (err)
  		goto out_put;
  
  	err = -ENOMEM;
  	p->holder_dir = kobject_create_and_add("holders", &pdev->kobj);
  	if (!p->holder_dir)
  		goto out_del;
  
  	dev_set_uevent_suppress(pdev, 0);
  	if (flags & ADDPART_FLAG_WHOLEDISK) {
  		err = device_create_file(pdev, &dev_attr_whole_disk);
  		if (err)
  			goto out_del;
  	}

  	err = hd_ref_init(p);
  	if (err) {
  		if (flags & ADDPART_FLAG_WHOLEDISK)
  			goto out_remove_file;
  		goto out_del;
  	}

  	/* everything is up and running, commence */
  	rcu_assign_pointer(ptbl->part[partno], p);
  
  	/* suppress uevent if the disk suppresses it */
  	if (!dev_get_uevent_suppress(ddev))
  		kobject_uevent(&pdev->kobj, KOBJ_ADD);

  	return p;

  
  out_free_info:
  	free_part_info(p);
  out_free_stats:
  	free_part_stats(p);
  out_free:
  	kfree(p);
  	return ERR_PTR(err);

  out_remove_file:
  	device_remove_file(pdev, &dev_attr_whole_disk);

  out_del:
  	kobject_put(p->holder_dir);
  	device_del(pdev);
  out_put:
  	put_device(pdev);

  	return ERR_PTR(err);
  }
  
  static bool disk_unlock_native_capacity(struct gendisk *disk)
  {
  	const struct block_device_operations *bdops = disk->fops;
  
  	if (bdops->unlock_native_capacity &&
  	    !(disk->flags & GENHD_FL_NATIVE_CAPACITY)) {
  		printk(KERN_CONT "enabling native capacity
  ");
  		bdops->unlock_native_capacity(disk);
  		disk->flags |= GENHD_FL_NATIVE_CAPACITY;
  		return true;
  	} else {
  		printk(KERN_CONT "truncated
  ");
  		return false;
  	}
  }

  static int drop_partitions(struct gendisk *disk, struct block_device *bdev)

  {

  	struct disk_part_iter piter;
  	struct hd_struct *part;

  	int res;

  	if (bdev->bd_part_count || bdev->bd_super)

  		return -EBUSY;
  	res = invalidate_partition(disk, 0);
  	if (res)
  		return res;
  
  	disk_part_iter_init(&piter, disk, DISK_PITER_INCL_EMPTY);
  	while ((part = disk_part_iter_next(&piter)))
  		delete_partition(disk, part->partno);
  	disk_part_iter_exit(&piter);

  	return 0;
  }

  static bool part_zone_aligned(struct gendisk *disk,
  			      struct block_device *bdev,
  			      sector_t from, sector_t size)
  {

  	unsigned int zone_sectors = bdev_zone_sectors(bdev);

  
  	/*
  	 * If this function is called, then the disk is a zoned block device
  	 * (host-aware or host-managed). This can be detected even if the
  	 * zoned block device support is disabled (CONFIG_BLK_DEV_ZONED not
  	 * set). In this case, however, only host-aware devices will be seen
  	 * as a block device is not created for host-managed devices. Without
  	 * zoned block device support, host-aware drives can still be used as
  	 * regular block devices (no zone operation) and their zone size will
  	 * be reported as 0. Allow this case.
  	 */

  	if (!zone_sectors)

  		return true;
  
  	/*
  	 * Check partition start and size alignement. If the drive has a
  	 * smaller last runt zone, ignore it and allow the partition to
  	 * use it. Check the zone size too: it should be a power of 2 number
  	 * of sectors.
  	 */

  	if (WARN_ON_ONCE(!is_power_of_2(zone_sectors))) {

  		u32 rem;

  		div_u64_rem(from, zone_sectors, &rem);

  		if (rem)
  			return false;
  		if ((from + size) < get_capacity(disk)) {

  			div_u64_rem(size, zone_sectors, &rem);

  			if (rem)
  				return false;
  		}
  
  	} else {

  		if (from & (zone_sectors - 1))

  			return false;
  		if ((from + size) < get_capacity(disk) &&

  		    (size & (zone_sectors - 1)))

  			return false;
  
  	}
  
  	return true;
  }

  int rescan_partitions(struct gendisk *disk, struct block_device *bdev)
  {
  	struct parsed_partitions *state = NULL;
  	struct hd_struct *part;
  	int p, highest, res;
  rescan:
  	if (state && !IS_ERR(state)) {

  		free_partitions(state);

  		state = NULL;
  	}
  
  	res = drop_partitions(disk, bdev);
  	if (res)
  		return res;

  	if (disk->fops->revalidate_disk)
  		disk->fops->revalidate_disk(disk);

  	check_disk_size_change(disk, bdev, true);

  	bdev->bd_invalidated = 0;
  	if (!get_capacity(disk) || !(state = check_partition(disk, bdev)))
  		return 0;
  	if (IS_ERR(state)) {
  		/*
  		 * I/O error reading the partition table.  If any
  		 * partition code tried to read beyond EOD, retry
  		 * after unlocking native capacity.
  		 */
  		if (PTR_ERR(state) == -ENOSPC) {
  			printk(KERN_WARNING "%s: partition table beyond EOD, ",
  			       disk->disk_name);
  			if (disk_unlock_native_capacity(disk))
  				goto rescan;
  		}
  		return -EIO;
  	}
  	/*
  	 * If any partition code tried to read beyond EOD, try
  	 * unlocking native capacity even if partition table is
  	 * successfully read as we could be missing some partitions.
  	 */
  	if (state->access_beyond_eod) {
  		printk(KERN_WARNING
  		       "%s: partition table partially beyond EOD, ",
  		       disk->disk_name);
  		if (disk_unlock_native_capacity(disk))
  			goto rescan;
  	}
  
  	/* tell userspace that the media / partition table may have changed */
  	kobject_uevent(&disk_to_dev(disk)->kobj, KOBJ_CHANGE);
  
  	/* Detect the highest partition number and preallocate
  	 * disk->part_tbl.  This is an optimization and not strictly
  	 * necessary.
  	 */
  	for (p = 1, highest = 0; p < state->limit; p++)
  		if (state->parts[p].size)
  			highest = p;
  
  	disk_expand_part_tbl(disk, highest);
  
  	/* add partitions */
  	for (p = 1; p < state->limit; p++) {
  		sector_t size, from;

  
  		size = state->parts[p].size;
  		if (!size)
  			continue;
  
  		from = state->parts[p].from;
  		if (from >= get_capacity(disk)) {
  			printk(KERN_WARNING
  			       "%s: p%d start %llu is beyond EOD, ",
  			       disk->disk_name, p, (unsigned long long) from);
  			if (disk_unlock_native_capacity(disk))
  				goto rescan;
  			continue;
  		}
  
  		if (from + size > get_capacity(disk)) {
  			printk(KERN_WARNING
  			       "%s: p%d size %llu extends beyond EOD, ",
  			       disk->disk_name, p, (unsigned long long) size);
  
  			if (disk_unlock_native_capacity(disk)) {
  				/* free state and restart */
  				goto rescan;
  			} else {
  				/*
  				 * we can not ignore partitions of broken tables
  				 * created by for example camera firmware, but
  				 * we limit them to the end of the disk to avoid
  				 * creating invalid block devices
  				 */
  				size = get_capacity(disk) - from;
  			}
  		}

  		/*
  		 * On a zoned block device, partitions should be aligned on the
  		 * device zone size (i.e. zone boundary crossing not allowed).
  		 * Otherwise, resetting the write pointer of the last zone of
  		 * one partition may impact the following partition.
  		 */
  		if (bdev_is_zoned(bdev) &&
  		    !part_zone_aligned(disk, bdev, from, size)) {
  			printk(KERN_WARNING
  			       "%s: p%d start %llu+%llu is not zone aligned
  ",
  			       disk->disk_name, p, (unsigned long long) from,
  			       (unsigned long long) size);
  			continue;
  		}

  		part = add_partition(disk, p, from, size,
  				     state->parts[p].flags,
  				     &state->parts[p].info);
  		if (IS_ERR(part)) {
  			printk(KERN_ERR " %s: p%d could not be added: %ld
  ",
  			       disk->disk_name, p, -PTR_ERR(part));
  			continue;
  		}
  #ifdef CONFIG_BLK_DEV_MD
  		if (state->parts[p].flags & ADDPART_FLAG_RAID)
  			md_autodetect_dev(part_to_dev(part)->devt);
  #endif
  	}

  	free_partitions(state);

  	return 0;
  }

  int invalidate_partitions(struct gendisk *disk, struct block_device *bdev)
  {
  	int res;
  
  	if (!bdev->bd_invalidated)
  		return 0;
  
  	res = drop_partitions(disk, bdev);
  	if (res)
  		return res;
  
  	set_capacity(disk, 0);

  	check_disk_size_change(disk, bdev, false);

  	bdev->bd_invalidated = 0;
  	/* tell userspace that the media / partition table may have changed */
  	kobject_uevent(&disk_to_dev(disk)->kobj, KOBJ_CHANGE);
  
  	return 0;
  }

  unsigned char *read_dev_sector(struct block_device *bdev, sector_t n, Sector *p)
  {

  	struct address_space *mapping = bdev->bd_inode->i_mapping;

  	struct page *page;

  	page = read_mapping_page(mapping, (pgoff_t)(n >> (PAGE_SHIFT-9)), NULL);

  	if (!IS_ERR(page)) {
  		if (PageError(page))
  			goto fail;
  		p->v = page;

  		return (unsigned char *)page_address(page) +  ((n & ((1 << (PAGE_SHIFT - 9)) - 1)) << 9);

  fail:

  		put_page(page);

  	}
  	p->v = NULL;
  	return NULL;
  }
  
  EXPORT_SYMBOL(read_dev_sector);