/* SPDX-License-Identifier: GPL-2.0 */
#ifndef _LINUX_SLUB_DEF_H
#define _LINUX_SLUB_DEF_H

/*
 * SLUB : A Slab allocator without object queues.
 *
 * (C) 2007 SGI, Christoph Lameter
 */
#include <linux/kfence.h>
#include <linux/kobject.h>
#include <linux/reciprocal_div.h>
#include <linux/local_lock.h>

enum stat_item {
        ALLOC_FASTPATH,         /* Allocation from cpu slab */
        ALLOC_SLOWPATH,         /* Allocation by getting a new cpu slab */
        FREE_FASTPATH,          /* Free to cpu slab */
        FREE_SLOWPATH,          /* Freeing not to cpu slab */
        FREE_FROZEN,            /* Freeing to frozen slab */
        FREE_ADD_PARTIAL,       /* Freeing moves slab to partial list */
        FREE_REMOVE_PARTIAL,    /* Freeing removes last object */
        ALLOC_FROM_PARTIAL,     /* Cpu slab acquired from node partial list */
        ALLOC_SLAB,             /* Cpu slab acquired from page allocator */
        ALLOC_REFILL,           /* Refill cpu slab from slab freelist */
        ALLOC_NODE_MISMATCH,    /* Switching cpu slab */
        FREE_SLAB,              /* Slab freed to the page allocator */
        CPUSLAB_FLUSH,          /* Abandoning of the cpu slab */
        DEACTIVATE_FULL,        /* Cpu slab was full when deactivated */
        DEACTIVATE_EMPTY,       /* Cpu slab was empty when deactivated */
        DEACTIVATE_TO_HEAD,     /* Cpu slab was moved to the head of partials */
        DEACTIVATE_TO_TAIL,     /* Cpu slab was moved to the tail of partials */
        DEACTIVATE_REMOTE_FREES,/* Slab contained remotely freed objects */
        DEACTIVATE_BYPASS,      /* Implicit deactivation */
        ORDER_FALLBACK,         /* Number of times fallback was necessary */
        CMPXCHG_DOUBLE_CPU_FAIL,/* Failure of this_cpu_cmpxchg_double */
        CMPXCHG_DOUBLE_FAIL,    /* Number of times that cmpxchg double did not match */
        CPU_PARTIAL_ALLOC,      /* Used cpu partial on alloc */
        CPU_PARTIAL_FREE,       /* Refill cpu partial on free */
        CPU_PARTIAL_NODE,       /* Refill cpu partial from node partial */
        CPU_PARTIAL_DRAIN,      /* Drain cpu partial to node partial */
        NR_SLUB_STAT_ITEMS };

/*
 * When changing the layout, make sure freelist and tid are still compatible
 * with this_cpu_cmpxchg_double() alignment requirements.
 */
struct kmem_cache_cpu {
        void **freelist;        /* Pointer to next available object */
        unsigned long tid;      /* Globally unique transaction id */
        struct page *page;      /* The slab from which we are allocating */
#ifdef CONFIG_SLUB_CPU_PARTIAL
        struct page *partial;   /* Partially allocated frozen slabs */
#endif
        local_lock_t lock;      /* Protects the fields above */
#ifdef CONFIG_SLUB_STATS
        unsigned stat[NR_SLUB_STAT_ITEMS];
#endif
};

#ifdef CONFIG_SLUB_CPU_PARTIAL
#define slub_percpu_partial(c)          ((c)->partial)

#define slub_set_percpu_partial(c, p)           \
({                                              \
        slub_percpu_partial(c) = (p)->next;     \
})

#define slub_percpu_partial_read_once(c)     READ_ONCE(slub_percpu_partial(c))
#else
#define slub_percpu_partial(c)                  NULL

#define slub_set_percpu_partial(c, p)

#define slub_percpu_partial_read_once(c)        NULL
#endif // CONFIG_SLUB_CPU_PARTIAL

/*
 * Word size structure that can be atomically updated or read and that
 * contains both the order and the number of objects that a slab of the
 * given order would contain.
 */
struct kmem_cache_order_objects {
        unsigned int x;
};

/*
 * Slab cache management.
 */
struct kmem_cache {
        struct kmem_cache_cpu __percpu *cpu_slab;
        /* Used for retrieving partial slabs, etc. */
        slab_flags_t flags;
        unsigned long min_partial;
        unsigned int size;      /* The size of an object including metadata */
        unsigned int object_size;/* The size of an object without metadata */
        struct reciprocal_value reciprocal_size;
        unsigned int offset;    /* Free pointer offset */
#ifdef CONFIG_SLUB_CPU_PARTIAL
        /* Number of per cpu partial objects to keep around */
        unsigned int cpu_partial;
#endif
        struct kmem_cache_order_objects oo;

        /* Allocation and freeing of slabs */
        struct kmem_cache_order_objects max;
        struct kmem_cache_order_objects min;
        gfp_t allocflags;       /* gfp flags to use on each alloc */
        int refcount;           /* Refcount for slab cache destroy */
        void (*ctor)(void *);
        unsigned int inuse;             /* Offset to metadata */
        unsigned int align;             /* Alignment */
        unsigned int red_left_pad;      /* Left redzone padding size */
        const char *name;       /* Name (only for display!) */
        struct list_head list;  /* List of slab caches */
#ifdef CONFIG_SYSFS
        struct kobject kobj;    /* For sysfs */
#endif
#ifdef CONFIG_SLAB_FREELIST_HARDENED
        unsigned long random;
#endif

#ifdef CONFIG_NUMA
        /*
         * Defragmentation by allocating from a remote node.
         */
        unsigned int remote_node_defrag_ratio;
#endif

#ifdef CONFIG_SLAB_FREELIST_RANDOM
        unsigned int *random_seq;
#endif

#ifdef CONFIG_KASAN
        struct kasan_cache kasan_info;
#endif

        unsigned int useroffset;        /* Usercopy region offset */
        unsigned int usersize;          /* Usercopy region size */

        struct kmem_cache_node *node[MAX_NUMNODES];
};

#ifdef CONFIG_SLUB_CPU_PARTIAL
#define slub_cpu_partial(s)             ((s)->cpu_partial)
#define slub_set_cpu_partial(s, n)              \
({                                              \
        slub_cpu_partial(s) = (n);              \
})
#else
#define slub_cpu_partial(s)             (0)
#define slub_set_cpu_partial(s, n)
#endif /* CONFIG_SLUB_CPU_PARTIAL */

#ifdef CONFIG_SYSFS
#define SLAB_SUPPORTS_SYSFS
void sysfs_slab_unlink(struct kmem_cache *);
void sysfs_slab_release(struct kmem_cache *);
#else
static inline void sysfs_slab_unlink(struct kmem_cache *s)
{
}
static inline void sysfs_slab_release(struct kmem_cache *s)
{
}
#endif

void object_err(struct kmem_cache *s, struct page *page,
                u8 *object, char *reason);

void *fixup_red_left(struct kmem_cache *s, void *p);

static inline void *nearest_obj(struct kmem_cache *cache, struct page *page,
                                void *x) {
        void *object = x - (x - page_address(page)) % cache->size;
        void *last_object = page_address(page) +
                (page->objects - 1) * cache->size;
        void *result = (unlikely(object > last_object)) ? last_object : object;

        result = fixup_red_left(cache, result);
        return result;
}

/* Determine object index from a given position */
static inline unsigned int __obj_to_index(const struct kmem_cache *cache,
                                          void *addr, void *obj)
{
        return reciprocal_divide(kasan_reset_tag(obj) - addr,
                                 cache->reciprocal_size);
}

static inline unsigned int obj_to_index(const struct kmem_cache *cache,
                                        const struct page *page, void *obj)
{
        if (is_kfence_address(obj))
                return 0;
        return __obj_to_index(cache, page_address(page), obj);
}

static inline int objs_per_slab_page(const struct kmem_cache *cache,
                                     const struct page *page)
{
        return page->objects;
}
#endif /* _LINUX_SLUB_DEF_H */