// SPDX-License-Identifier: GPL-2.0-only
/*
 * VMware VMCI Driver
 *
 * Copyright (C) 2012 VMware, Inc. All rights reserved.
 */

#include <linux/slab.h>
#include "vmci_handle_array.h"

struct vmci_handle_arr *vmci_handle_arr_create(u32 capacity, u32 max_capacity)
{
        struct vmci_handle_arr *array;

        if (max_capacity == 0 || capacity > max_capacity)
                return NULL;

        if (capacity == 0)
                capacity = min((u32)VMCI_HANDLE_ARRAY_DEFAULT_CAPACITY,
                               max_capacity);

        array = kmalloc_flex(*array, entries, capacity, GFP_ATOMIC);
        if (!array)
                return NULL;

        array->capacity = capacity;
        array->max_capacity = max_capacity;
        array->size = 0;

        return array;
}

void vmci_handle_arr_destroy(struct vmci_handle_arr *array)
{
        kfree(array);
}

int vmci_handle_arr_append_entry(struct vmci_handle_arr **array_ptr,
                                 struct vmci_handle handle)
{
        struct vmci_handle_arr *array = *array_ptr;

        if (unlikely(array->size >= array->capacity)) {
                /* reallocate. */
                struct vmci_handle_arr *new_array;
                u32 capacity_bump = min(array->max_capacity - array->capacity,
                                        array->capacity);
                size_t new_size = struct_size(array, entries,
                                              size_add(array->capacity, capacity_bump));

                if (array->size >= array->max_capacity)
                        return VMCI_ERROR_NO_MEM;

                new_array = krealloc(array, new_size, GFP_ATOMIC);
                if (!new_array)
                        return VMCI_ERROR_NO_MEM;

                new_array->capacity += capacity_bump;
                *array_ptr = array = new_array;
        }

        array->entries[array->size] = handle;
        array->size++;

        return VMCI_SUCCESS;
}

/*
 * Handle that was removed, VMCI_INVALID_HANDLE if entry not found.
 */
struct vmci_handle vmci_handle_arr_remove_entry(struct vmci_handle_arr *array,
                                                struct vmci_handle entry_handle)
{
        struct vmci_handle handle = VMCI_INVALID_HANDLE;
        u32 i;

        for (i = 0; i < array->size; i++) {
                if (vmci_handle_is_equal(array->entries[i], entry_handle)) {
                        handle = array->entries[i];
                        array->size--;
                        array->entries[i] = array->entries[array->size];
                        array->entries[array->size] = VMCI_INVALID_HANDLE;
                        break;
                }
        }

        return handle;
}

/*
 * Handle that was removed, VMCI_INVALID_HANDLE if array was empty.
 */
struct vmci_handle vmci_handle_arr_remove_tail(struct vmci_handle_arr *array)
{
        struct vmci_handle handle = VMCI_INVALID_HANDLE;

        if (array->size) {
                array->size--;
                handle = array->entries[array->size];
                array->entries[array->size] = VMCI_INVALID_HANDLE;
        }

        return handle;
}

/*
 * Handle at given index, VMCI_INVALID_HANDLE if invalid index.
 */
struct vmci_handle
vmci_handle_arr_get_entry(const struct vmci_handle_arr *array, u32 index)
{
        if (unlikely(index >= array->size))
                return VMCI_INVALID_HANDLE;

        return array->entries[index];
}

bool vmci_handle_arr_has_entry(const struct vmci_handle_arr *array,
                               struct vmci_handle entry_handle)
{
        u32 i;

        for (i = 0; i < array->size; i++)
                if (vmci_handle_is_equal(array->entries[i], entry_handle))
                        return true;

        return false;
}

/*
 * NULL if the array is empty. Otherwise, a pointer to the array
 * of VMCI handles in the handle array.
 */
struct vmci_handle *vmci_handle_arr_get_handles(struct vmci_handle_arr *array)
{
        if (array->size)
                return array->entries;

        return NULL;
}