VMCI: handle array implementation.

/*

 * VMware VMCI Driver

 *

 * Copyright (C) 2012 VMware, Inc. All rights reserved.

 *

 * This program is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License as published by the

 * Free Software Foundation version 2 and no later version.

 *

 * This program is distributed in the hope that it will be useful, but

 * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY

 * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

 * for more details.

 */

#include <linux/slab.h>

#include "vmci_handle_array.h"

static size_t handle_arr_calc_size(size_t capacity)

{

	return sizeof(struct vmci_handle_arr) +

	    capacity * sizeof(struct vmci_handle);

}

struct vmci_handle_arr *vmci_handle_arr_create(size_t capacity)

{

	struct vmci_handle_arr *array;

	if (capacity == 0)

		capacity = VMCI_HANDLE_ARRAY_DEFAULT_SIZE;

	array = kmalloc(handle_arr_calc_size(capacity), GFP_ATOMIC);

	if (!array)

		return NULL;

	array->capacity = capacity;

	array->size = 0;

	return array;

}

void vmci_handle_arr_destroy(struct vmci_handle_arr *array)

{

	kfree(array);

}

void 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;

		size_t new_capacity = array->capacity * VMCI_ARR_CAP_MULT;

		size_t new_size = handle_arr_calc_size(new_capacity);

		new_array = krealloc(array, new_size, GFP_ATOMIC);

		if (!new_array)

			return;

		new_array->capacity = new_capacity;

		*array_ptr = array = new_array;

	}

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

	array->size++;

}

/*

 * 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;

	size_t 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, size_t 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)

{

	size_t 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;

}

/*

 * VMware VMCI Driver

 *

 * Copyright (C) 2012 VMware, Inc. All rights reserved.

 *

 * This program is free software; you can redistribute it and/or modify it

 * under the terms of the GNU General Public License as published by the

 * Free Software Foundation version 2 and no later version.

 *

 * This program is distributed in the hope that it will be useful, but

 * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY

 * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

 * for more details.

 */

#ifndef _VMCI_HANDLE_ARRAY_H_

#define _VMCI_HANDLE_ARRAY_H_

#include <linux/vmw_vmci_defs.h>

#include <linux/types.h>

#define VMCI_HANDLE_ARRAY_DEFAULT_SIZE 4

#define VMCI_ARR_CAP_MULT 2	/* Array capacity multiplier */

struct vmci_handle_arr {

	size_t capacity;

	size_t size;

	struct vmci_handle entries[];

};

struct vmci_handle_arr *vmci_handle_arr_create(size_t capacity);

void vmci_handle_arr_destroy(struct vmci_handle_arr *array);

void vmci_handle_arr_append_entry(struct vmci_handle_arr **array_ptr,

				  struct vmci_handle handle);

struct vmci_handle vmci_handle_arr_remove_entry(struct vmci_handle_arr *array,

						struct vmci_handle

						entry_handle);

struct vmci_handle vmci_handle_arr_remove_tail(struct vmci_handle_arr *array);

struct vmci_handle

vmci_handle_arr_get_entry(const struct vmci_handle_arr *array, size_t index);

bool vmci_handle_arr_has_entry(const struct vmci_handle_arr *array,

			       struct vmci_handle entry_handle);

struct vmci_handle *vmci_handle_arr_get_handles(struct vmci_handle_arr *array);

static inline size_t vmci_handle_arr_get_size(

	const struct vmci_handle_arr *array)

{

	return array->size;

}

#endif /* _VMCI_HANDLE_ARRAY_H_ */