1 /*
2  * VMware VMCI Driver
3  *
4  * Copyright (C) 2012 VMware, Inc. All rights reserved.
5  *
6  * This program is free software; you can redistribute it and/or modify it
7  * under the terms of the GNU General Public License as published by the
8  * Free Software Foundation version 2 and no later version.
9  *
10  * This program is distributed in the hope that it will be useful, but
11  * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
12  * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
13  * for more details.
14  */
15 
16 #include <linux/slab.h>
17 #include "vmci_handle_array.h"
18 
19 static size_t handle_arr_calc_size(size_t capacity)
20 {
21 	return sizeof(struct vmci_handle_arr) +
22 	    capacity * sizeof(struct vmci_handle);
23 }
24 
25 struct vmci_handle_arr *vmci_handle_arr_create(size_t capacity)
26 {
27 	struct vmci_handle_arr *array;
28 
29 	if (capacity == 0)
30 		capacity = VMCI_HANDLE_ARRAY_DEFAULT_SIZE;
31 
32 	array = kmalloc(handle_arr_calc_size(capacity), GFP_ATOMIC);
33 	if (!array)
34 		return NULL;
35 
36 	array->capacity = capacity;
37 	array->size = 0;
38 
39 	return array;
40 }
41 
42 void vmci_handle_arr_destroy(struct vmci_handle_arr *array)
43 {
44 	kfree(array);
45 }
46 
47 void vmci_handle_arr_append_entry(struct vmci_handle_arr **array_ptr,
48 				  struct vmci_handle handle)
49 {
50 	struct vmci_handle_arr *array = *array_ptr;
51 
52 	if (unlikely(array->size >= array->capacity)) {
53 		/* reallocate. */
54 		struct vmci_handle_arr *new_array;
55 		size_t new_capacity = array->capacity * VMCI_ARR_CAP_MULT;
56 		size_t new_size = handle_arr_calc_size(new_capacity);
57 
58 		new_array = krealloc(array, new_size, GFP_ATOMIC);
59 		if (!new_array)
60 			return;
61 
62 		new_array->capacity = new_capacity;
63 		*array_ptr = array = new_array;
64 	}
65 
66 	array->entries[array->size] = handle;
67 	array->size++;
68 }
69 
70 /*
71  * Handle that was removed, VMCI_INVALID_HANDLE if entry not found.
72  */
73 struct vmci_handle vmci_handle_arr_remove_entry(struct vmci_handle_arr *array,
74 						struct vmci_handle entry_handle)
75 {
76 	struct vmci_handle handle = VMCI_INVALID_HANDLE;
77 	size_t i;
78 
79 	for (i = 0; i < array->size; i++) {
80 		if (vmci_handle_is_equal(array->entries[i], entry_handle)) {
81 			handle = array->entries[i];
82 			array->size--;
83 			array->entries[i] = array->entries[array->size];
84 			array->entries[array->size] = VMCI_INVALID_HANDLE;
85 			break;
86 		}
87 	}
88 
89 	return handle;
90 }
91 
92 /*
93  * Handle that was removed, VMCI_INVALID_HANDLE if array was empty.
94  */
95 struct vmci_handle vmci_handle_arr_remove_tail(struct vmci_handle_arr *array)
96 {
97 	struct vmci_handle handle = VMCI_INVALID_HANDLE;
98 
99 	if (array->size) {
100 		array->size--;
101 		handle = array->entries[array->size];
102 		array->entries[array->size] = VMCI_INVALID_HANDLE;
103 	}
104 
105 	return handle;
106 }
107 
108 /*
109  * Handle at given index, VMCI_INVALID_HANDLE if invalid index.
110  */
111 struct vmci_handle
112 vmci_handle_arr_get_entry(const struct vmci_handle_arr *array, size_t index)
113 {
114 	if (unlikely(index >= array->size))
115 		return VMCI_INVALID_HANDLE;
116 
117 	return array->entries[index];
118 }
119 
120 bool vmci_handle_arr_has_entry(const struct vmci_handle_arr *array,
121 			       struct vmci_handle entry_handle)
122 {
123 	size_t i;
124 
125 	for (i = 0; i < array->size; i++)
126 		if (vmci_handle_is_equal(array->entries[i], entry_handle))
127 			return true;
128 
129 	return false;
130 }
131 
132 /*
133  * NULL if the array is empty. Otherwise, a pointer to the array
134  * of VMCI handles in the handle array.
135  */
136 struct vmci_handle *vmci_handle_arr_get_handles(struct vmci_handle_arr *array)
137 {
138 	if (array->size)
139 		return array->entries;
140 
141 	return NULL;
142 }
143