/* SPDX-License-Identifier: GPL-2.0 */

#ifndef _BCACHE_UTIL_H
#define _BCACHE_UTIL_H

#include <linux/blkdev.h>
#include <linux/errno.h>
#include <linux/kernel.h>
#include <linux/sched/clock.h>
#include <linux/llist.h>
#include <linux/ratelimit.h>
#include <linux/vmalloc.h>
#include <linux/workqueue.h>
#include <linux/crc64.h>

#include "closure.h"

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) do {} while (0); } 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 = kvmalloc(_bytes, (gfp) & GFP_KERNEL);            \
        (heap)->data;                                                   \
})

#define free_heap(heap)                                                 \
do {                                                                    \
        kvfree((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 = kvmalloc(_bytes, (gfp) & GFP_KERNEL);            \
        (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 {                                                                    \
        kvfree((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 *cp, int *res);
int bch_strtouint_h(const char *cp, unsigned int *res);
int bch_strtoll_h(const char *cp, long long *res);
int bch_strtoull_h(const char *cp, unsigned long long *res);

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;                                                             \
})

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);

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 int 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);        \
        sysfs_print(name ## _ ##max_duration ## _ ## duration_units,    \
                        div_u64((stats)->max_duration,                  \
                                NSEC_PER_ ## 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 second
         * The units here correspond to the units passed to bch_next_delay()
         */
        atomic_long_t           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)

static inline uint64_t bch_crc64(const void *p, size_t len)
{
        uint64_t crc = 0xffffffffffffffffULL;

        crc = crc64_be(crc, p, len);
        return crc ^ 0xffffffffffffffffULL;
}

/*
 * A stepwise-linear pseudo-exponential.  This returns 1 << (x >>
 * frac_bits), with the less-significant bits filled in by linear
 * interpolation.
 *
 * This can also be interpreted as a floating-point number format,
 * where the low frac_bits are the mantissa (with implicit leading
 * 1 bit), and the more significant bits are the exponent.
 * The return value is 1.mantissa * 2^exponent.
 *
 * The way this is used, fract_bits is 6 and the largest possible
 * input is CONGESTED_MAX-1 = 1023 (exponent 16, mantissa 0x1.fc),
 * so the maximum output is 0x1fc00.
 */
static inline unsigned int fract_exp_two(unsigned int x,
                                         unsigned int fract_bits)
{
        unsigned int mantissa = 1 << fract_bits;        /* Implicit bit */

        mantissa += x & (mantissa - 1);
        x >>= fract_bits;       /* The exponent */
        /* Largest intermediate value 0x7f0000 */
        return mantissa << x >> fract_bits;
}

void bch_bio_map(struct bio *bio, void *base);
int bch_bio_alloc_pages(struct bio *bio, gfp_t gfp_mask);

#endif /* _BCACHE_UTIL_H */