#ifndef _BCACHE_UTIL_H
  #define _BCACHE_UTIL_H
  
  #include <linux/blkdev.h>
  #include <linux/errno.h>
  #include <linux/kernel.h>
  #include <linux/llist.h>
  #include <linux/ratelimit.h>
  #include <linux/vmalloc.h>
  #include <linux/workqueue.h>
  
  #include "closure.h"
  
  #define PAGE_SECTORS		(PAGE_SIZE / 512)
  
  struct closure;
  
  #ifdef CONFIG_BCACHE_DEBUG
  
  #define EBUG_ON(cond)			BUG_ON(cond)
  #define atomic_dec_bug(v)	BUG_ON(atomic_dec_return(v) < 0)
  #define atomic_inc_bug(v, i)	BUG_ON(atomic_inc_return(v) <= i)
  
  #else /* DEBUG */
  
  #define EBUG_ON(cond)			do { if (cond); } while (0)
  #define atomic_dec_bug(v)	atomic_dec(v)
  #define atomic_inc_bug(v, i)	atomic_inc(v)
  
  #endif
  
  #define DECLARE_HEAP(type, name)					\
  	struct {							\
  		size_t size, used;					\
  		type *data;						\
  	} name
  
  #define init_heap(heap, _size, gfp)					\
  ({									\
  	size_t _bytes;							\
  	(heap)->used = 0;						\
  	(heap)->size = (_size);						\
  	_bytes = (heap)->size * sizeof(*(heap)->data);			\
  	(heap)->data = NULL;						\
  	if (_bytes < KMALLOC_MAX_SIZE)					\
  		(heap)->data = kmalloc(_bytes, (gfp));			\
  	if ((!(heap)->data) && ((gfp) & GFP_KERNEL))			\
  		(heap)->data = vmalloc(_bytes);				\
  	(heap)->data;							\
  })
  
  #define free_heap(heap)							\
  do {									\
  	if (is_vmalloc_addr((heap)->data))				\
  		vfree((heap)->data);					\
  	else								\
  		kfree((heap)->data);					\
  	(heap)->data = NULL;						\
  } while (0)
  
  #define heap_swap(h, i, j)	swap((h)->data[i], (h)->data[j])
  
  #define heap_sift(h, i, cmp)						\
  do {									\
  	size_t _r, _j = i;						\
  									\
  	for (; _j * 2 + 1 < (h)->used; _j = _r) {			\
  		_r = _j * 2 + 1;					\
  		if (_r + 1 < (h)->used &&				\
  		    cmp((h)->data[_r], (h)->data[_r + 1]))		\
  			_r++;						\
  									\
  		if (cmp((h)->data[_r], (h)->data[_j]))			\
  			break;						\
  		heap_swap(h, _r, _j);					\
  	}								\
  } while (0)
  
  #define heap_sift_down(h, i, cmp)					\
  do {									\
  	while (i) {							\
  		size_t p = (i - 1) / 2;					\
  		if (cmp((h)->data[i], (h)->data[p]))			\
  			break;						\
  		heap_swap(h, i, p);					\
  		i = p;							\
  	}								\
  } while (0)
  
  #define heap_add(h, d, cmp)						\
  ({									\
  	bool _r = !heap_full(h);					\
  	if (_r) {							\
  		size_t _i = (h)->used++;				\
  		(h)->data[_i] = d;					\
  									\
  		heap_sift_down(h, _i, cmp);				\
  		heap_sift(h, _i, cmp);					\
  	}								\
  	_r;								\
  })
  
  #define heap_pop(h, d, cmp)						\
  ({									\
  	bool _r = (h)->used;						\
  	if (_r) {							\
  		(d) = (h)->data[0];					\
  		(h)->used--;						\
  		heap_swap(h, 0, (h)->used);				\
  		heap_sift(h, 0, cmp);					\
  	}								\
  	_r;								\
  })
  
  #define heap_peek(h)	((h)->used ? (h)->data[0] : NULL)
  
  #define heap_full(h)	((h)->used == (h)->size)
  
  #define DECLARE_FIFO(type, name)					\
  	struct {							\
  		size_t front, back, size, mask;				\
  		type *data;						\
  	} name
  
  #define fifo_for_each(c, fifo, iter)					\
  	for (iter = (fifo)->front;					\
  	     c = (fifo)->data[iter], iter != (fifo)->back;		\
  	     iter = (iter + 1) & (fifo)->mask)
  
  #define __init_fifo(fifo, gfp)						\
  ({									\
  	size_t _allocated_size, _bytes;					\
  	BUG_ON(!(fifo)->size);						\
  									\
  	_allocated_size = roundup_pow_of_two((fifo)->size + 1);		\
  	_bytes = _allocated_size * sizeof(*(fifo)->data);		\
  									\
  	(fifo)->mask = _allocated_size - 1;				\
  	(fifo)->front = (fifo)->back = 0;				\
  	(fifo)->data = NULL;						\
  									\
  	if (_bytes < KMALLOC_MAX_SIZE)					\
  		(fifo)->data = kmalloc(_bytes, (gfp));			\
  	if ((!(fifo)->data) && ((gfp) & GFP_KERNEL))			\
  		(fifo)->data = vmalloc(_bytes);				\
  	(fifo)->data;							\
  })
  
  #define init_fifo_exact(fifo, _size, gfp)				\
  ({									\
  	(fifo)->size = (_size);						\
  	__init_fifo(fifo, gfp);						\
  })
  
  #define init_fifo(fifo, _size, gfp)					\
  ({									\
  	(fifo)->size = (_size);						\
  	if ((fifo)->size > 4)						\
  		(fifo)->size = roundup_pow_of_two((fifo)->size) - 1;	\
  	__init_fifo(fifo, gfp);						\
  })
  
  #define free_fifo(fifo)							\
  do {									\
  	if (is_vmalloc_addr((fifo)->data))				\
  		vfree((fifo)->data);					\
  	else								\
  		kfree((fifo)->data);					\
  	(fifo)->data = NULL;						\
  } while (0)
  
  #define fifo_used(fifo)		(((fifo)->back - (fifo)->front) & (fifo)->mask)
  #define fifo_free(fifo)		((fifo)->size - fifo_used(fifo))
  
  #define fifo_empty(fifo)	(!fifo_used(fifo))
  #define fifo_full(fifo)		(!fifo_free(fifo))
  
  #define fifo_front(fifo)	((fifo)->data[(fifo)->front])
  #define fifo_back(fifo)							\
  	((fifo)->data[((fifo)->back - 1) & (fifo)->mask])
  
  #define fifo_idx(fifo, p)	(((p) - &fifo_front(fifo)) & (fifo)->mask)
  
  #define fifo_push_back(fifo, i)						\
  ({									\
  	bool _r = !fifo_full((fifo));					\
  	if (_r) {							\
  		(fifo)->data[(fifo)->back++] = (i);			\
  		(fifo)->back &= (fifo)->mask;				\
  	}								\
  	_r;								\
  })
  
  #define fifo_pop_front(fifo, i)						\
  ({									\
  	bool _r = !fifo_empty((fifo));					\
  	if (_r) {							\
  		(i) = (fifo)->data[(fifo)->front++];			\
  		(fifo)->front &= (fifo)->mask;				\
  	}								\
  	_r;								\
  })
  
  #define fifo_push_front(fifo, i)					\
  ({									\
  	bool _r = !fifo_full((fifo));					\
  	if (_r) {							\
  		--(fifo)->front;					\
  		(fifo)->front &= (fifo)->mask;				\
  		(fifo)->data[(fifo)->front] = (i);			\
  	}								\
  	_r;								\
  })
  
  #define fifo_pop_back(fifo, i)						\
  ({									\
  	bool _r = !fifo_empty((fifo));					\
  	if (_r) {							\
  		--(fifo)->back;						\
  		(fifo)->back &= (fifo)->mask;				\
  		(i) = (fifo)->data[(fifo)->back]			\
  	}								\
  	_r;								\
  })
  
  #define fifo_push(fifo, i)	fifo_push_back(fifo, (i))
  #define fifo_pop(fifo, i)	fifo_pop_front(fifo, (i))
  
  #define fifo_swap(l, r)							\
  do {									\
  	swap((l)->front, (r)->front);					\
  	swap((l)->back, (r)->back);					\
  	swap((l)->size, (r)->size);					\
  	swap((l)->mask, (r)->mask);					\
  	swap((l)->data, (r)->data);					\
  } while (0)
  
  #define fifo_move(dest, src)						\
  do {									\
  	typeof(*((dest)->data)) _t;					\
  	while (!fifo_full(dest) &&					\
  	       fifo_pop(src, _t))					\
  		fifo_push(dest, _t);					\
  } while (0)
  
  /*
   * Simple array based allocator - preallocates a number of elements and you can
   * never allocate more than that, also has no locking.
   *
   * Handy because if you know you only need a fixed number of elements you don't
   * have to worry about memory allocation failure, and sometimes a mempool isn't
   * what you want.
   *
   * We treat the free elements as entries in a singly linked list, and the
   * freelist as a stack - allocating and freeing push and pop off the freelist.
   */
  
  #define DECLARE_ARRAY_ALLOCATOR(type, name, size)			\
  	struct {							\
  		type	*freelist;					\
  		type	data[size];					\
  	} name
  
  #define array_alloc(array)						\
  ({									\
  	typeof((array)->freelist) _ret = (array)->freelist;		\
  									\
  	if (_ret)							\
  		(array)->freelist = *((typeof((array)->freelist) *) _ret);\
  									\
  	_ret;								\
  })
  
  #define array_free(array, ptr)						\
  do {									\
  	typeof((array)->freelist) _ptr = ptr;				\
  									\
  	*((typeof((array)->freelist) *) _ptr) = (array)->freelist;	\
  	(array)->freelist = _ptr;					\
  } while (0)
  
  #define array_allocator_init(array)					\
  do {									\
  	typeof((array)->freelist) _i;					\
  									\
  	BUILD_BUG_ON(sizeof((array)->data[0]) < sizeof(void *));	\
  	(array)->freelist = NULL;					\
  									\
  	for (_i = (array)->data;					\
  	     _i < (array)->data + ARRAY_SIZE((array)->data);		\
  	     _i++)							\
  		array_free(array, _i);					\
  } while (0)
  
  #define array_freelist_empty(array)	((array)->freelist == NULL)
  
  #define ANYSINT_MAX(t)							\
  	((((t) 1 << (sizeof(t) * 8 - 2)) - (t) 1) * (t) 2 + (t) 1)
  
  int bch_strtoint_h(const char *, int *);
  int bch_strtouint_h(const char *, unsigned int *);
  int bch_strtoll_h(const char *, long long *);
  int bch_strtoull_h(const char *, unsigned long long *);
  
  static inline int bch_strtol_h(const char *cp, long *res)
  {
  #if BITS_PER_LONG == 32
  	return bch_strtoint_h(cp, (int *) res);
  #else
  	return bch_strtoll_h(cp, (long long *) res);
  #endif
  }
  
  static inline int bch_strtoul_h(const char *cp, long *res)
  {
  #if BITS_PER_LONG == 32
  	return bch_strtouint_h(cp, (unsigned int *) res);
  #else
  	return bch_strtoull_h(cp, (unsigned long long *) res);
  #endif
  }
  
  #define strtoi_h(cp, res)						\
  	(__builtin_types_compatible_p(typeof(*res), int)		\
  	? bch_strtoint_h(cp, (void *) res)				\
  	: __builtin_types_compatible_p(typeof(*res), long)		\
  	? bch_strtol_h(cp, (void *) res)				\
  	: __builtin_types_compatible_p(typeof(*res), long long)		\
  	? bch_strtoll_h(cp, (void *) res)				\
  	: __builtin_types_compatible_p(typeof(*res), unsigned int)	\
  	? bch_strtouint_h(cp, (void *) res)				\
  	: __builtin_types_compatible_p(typeof(*res), unsigned long)	\
  	? bch_strtoul_h(cp, (void *) res)				\
  	: __builtin_types_compatible_p(typeof(*res), unsigned long long)\
  	? bch_strtoull_h(cp, (void *) res) : -EINVAL)
  
  #define strtoul_safe(cp, var)						\
  ({									\
  	unsigned long _v;						\
  	int _r = kstrtoul(cp, 10, &_v);					\
  	if (!_r)							\
  		var = _v;						\
  	_r;								\
  })
  
  #define strtoul_safe_clamp(cp, var, min, max)				\
  ({									\
  	unsigned long _v;						\
  	int _r = kstrtoul(cp, 10, &_v);					\
  	if (!_r)							\
  		var = clamp_t(typeof(var), _v, min, max);		\
  	_r;								\
  })
  
  #define snprint(buf, size, var)						\
  	snprintf(buf, size,						\
  		__builtin_types_compatible_p(typeof(var), int)		\
  		     ? "%i
  " :						\
  		__builtin_types_compatible_p(typeof(var), unsigned)	\
  		     ? "%u
  " :						\
  		__builtin_types_compatible_p(typeof(var), long)		\
  		     ? "%li
  " :					\
  		__builtin_types_compatible_p(typeof(var), unsigned long)\
  		     ? "%lu
  " :					\
  		__builtin_types_compatible_p(typeof(var), int64_t)	\
  		     ? "%lli
  " :					\
  		__builtin_types_compatible_p(typeof(var), uint64_t)	\
  		     ? "%llu
  " :					\
  		__builtin_types_compatible_p(typeof(var), const char *)	\
  		     ? "%s
  " : "%i
  ", var)
  
  ssize_t bch_hprint(char *buf, int64_t v);
  
  bool bch_is_zero(const char *p, size_t n);
  int bch_parse_uuid(const char *s, char *uuid);
  
  ssize_t bch_snprint_string_list(char *buf, size_t size, const char * const list[],
  			    size_t selected);
  
  ssize_t bch_read_string_list(const char *buf, const char * const list[]);
  
  struct time_stats {
  	spinlock_t	lock;
  	/*
  	 * all fields are in nanoseconds, averages are ewmas stored left shifted
  	 * by 8
  	 */
  	uint64_t	max_duration;
  	uint64_t	average_duration;
  	uint64_t	average_frequency;
  	uint64_t	last;
  };
  
  void bch_time_stats_update(struct time_stats *stats, uint64_t time);
  
  static inline unsigned local_clock_us(void)
  {
  	return local_clock() >> 10;
  }
  
  #define NSEC_PER_ns			1L
  #define NSEC_PER_us			NSEC_PER_USEC
  #define NSEC_PER_ms			NSEC_PER_MSEC
  #define NSEC_PER_sec			NSEC_PER_SEC
  
  #define __print_time_stat(stats, name, stat, units)			\
  	sysfs_print(name ## _ ## stat ## _ ## units,			\
  		    div_u64((stats)->stat >> 8, NSEC_PER_ ## units))
  
  #define sysfs_print_time_stats(stats, name,				\
  			       frequency_units,				\
  			       duration_units)				\
  do {									\
  	__print_time_stat(stats, name,					\
  			  average_frequency,	frequency_units);	\
  	__print_time_stat(stats, name,					\
  			  average_duration,	duration_units);	\
  	__print_time_stat(stats, name,					\
  			  max_duration,		duration_units);	\
  									\
  	sysfs_print(name ## _last_ ## frequency_units, (stats)->last	\
  		    ? div_s64(local_clock() - (stats)->last,		\
  			      NSEC_PER_ ## frequency_units)		\
  		    : -1LL);						\
  } while (0)
  
  #define sysfs_time_stats_attribute(name,				\
  				   frequency_units,			\
  				   duration_units)			\
  read_attribute(name ## _average_frequency_ ## frequency_units);		\
  read_attribute(name ## _average_duration_ ## duration_units);		\
  read_attribute(name ## _max_duration_ ## duration_units);		\
  read_attribute(name ## _last_ ## frequency_units)
  
  #define sysfs_time_stats_attribute_list(name,				\
  					frequency_units,		\
  					duration_units)			\
  &sysfs_ ## name ## _average_frequency_ ## frequency_units,		\
  &sysfs_ ## name ## _average_duration_ ## duration_units,		\
  &sysfs_ ## name ## _max_duration_ ## duration_units,			\
  &sysfs_ ## name ## _last_ ## frequency_units,
  
  #define ewma_add(ewma, val, weight, factor)				\
  ({									\
  	(ewma) *= (weight) - 1;						\
  	(ewma) += (val) << factor;					\
  	(ewma) /= (weight);						\
  	(ewma) >> factor;						\
  })
  
  struct bch_ratelimit {
  	/* Next time we want to do some work, in nanoseconds */
  	uint64_t		next;
  
  	/*
  	 * Rate at which we want to do work, in units per nanosecond
  	 * The units here correspond to the units passed to bch_next_delay()
  	 */
  	unsigned		rate;
  };
  
  static inline void bch_ratelimit_reset(struct bch_ratelimit *d)
  {
  	d->next = local_clock();
  }
  
  uint64_t bch_next_delay(struct bch_ratelimit *d, uint64_t done);
  
  #define __DIV_SAFE(n, d, zero)						\
  ({									\
  	typeof(n) _n = (n);						\
  	typeof(d) _d = (d);						\
  	_d ? _n / _d : zero;						\
  })
  
  #define DIV_SAFE(n, d)	__DIV_SAFE(n, d, 0)
  
  #define container_of_or_null(ptr, type, member)				\
  ({									\
  	typeof(ptr) _ptr = ptr;						\
  	_ptr ? container_of(_ptr, type, member) : NULL;			\
  })
  
  #define RB_INSERT(root, new, member, cmp)				\
  ({									\
  	__label__ dup;							\
  	struct rb_node **n = &(root)->rb_node, *parent = NULL;		\
  	typeof(new) this;						\
  	int res, ret = -1;						\
  									\
  	while (*n) {							\
  		parent = *n;						\
  		this = container_of(*n, typeof(*(new)), member);	\
  		res = cmp(new, this);					\
  		if (!res)						\
  			goto dup;					\
  		n = res < 0						\
  			? &(*n)->rb_left				\
  			: &(*n)->rb_right;				\
  	}								\
  									\
  	rb_link_node(&(new)->member, parent, n);			\
  	rb_insert_color(&(new)->member, root);				\
  	ret = 0;							\
  dup:									\
  	ret;								\
  })
  
  #define RB_SEARCH(root, search, member, cmp)				\
  ({									\
  	struct rb_node *n = (root)->rb_node;				\
  	typeof(&(search)) this, ret = NULL;				\
  	int res;							\
  									\
  	while (n) {							\
  		this = container_of(n, typeof(search), member);		\
  		res = cmp(&(search), this);				\
  		if (!res) {						\
  			ret = this;					\
  			break;						\
  		}							\
  		n = res < 0						\
  			? n->rb_left					\
  			: n->rb_right;					\
  	}								\
  	ret;								\
  })
  
  #define RB_GREATER(root, search, member, cmp)				\
  ({									\
  	struct rb_node *n = (root)->rb_node;				\
  	typeof(&(search)) this, ret = NULL;				\
  	int res;							\
  									\
  	while (n) {							\
  		this = container_of(n, typeof(search), member);		\
  		res = cmp(&(search), this);				\
  		if (res < 0) {						\
  			ret = this;					\
  			n = n->rb_left;					\
  		} else							\
  			n = n->rb_right;				\
  	}								\
  	ret;								\
  })
  
  #define RB_FIRST(root, type, member)					\
  	container_of_or_null(rb_first(root), type, member)
  
  #define RB_LAST(root, type, member)					\
  	container_of_or_null(rb_last(root), type, member)
  
  #define RB_NEXT(ptr, member)						\
  	container_of_or_null(rb_next(&(ptr)->member), typeof(*ptr), member)
  
  #define RB_PREV(ptr, member)						\
  	container_of_or_null(rb_prev(&(ptr)->member), typeof(*ptr), member)
  
  /* Does linear interpolation between powers of two */
  static inline unsigned fract_exp_two(unsigned x, unsigned fract_bits)
  {
  	unsigned fract = x & ~(~0 << fract_bits);
  
  	x >>= fract_bits;
  	x   = 1 << x;
  	x  += (x * fract) >> fract_bits;
  
  	return x;
  }
  
  void bch_bio_map(struct bio *bio, void *base);
  
  static inline sector_t bdev_sectors(struct block_device *bdev)
  {
  	return bdev->bd_inode->i_size >> 9;
  }
  
  #define closure_bio_submit(bio, cl, dev)				\
  do {									\
  	closure_get(cl);						\
  	bch_generic_make_request(bio, &(dev)->bio_split_hook);		\
  } while (0)
  
  uint64_t bch_crc64_update(uint64_t, const void *, size_t);
  uint64_t bch_crc64(const void *, size_t);
  
  #endif /* _BCACHE_UTIL_H */