1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * VMware VMCI Driver
4  *
5  * Copyright (C) 2012 VMware, Inc. All rights reserved.
6  */
7 
8 #include <linux/slab.h>
9 #include "vmci_handle_array.h"
10 
11 static size_t handle_arr_calc_size(u32 capacity)
12 {
13 	return VMCI_HANDLE_ARRAY_HEADER_SIZE +
14 	    capacity * sizeof(struct vmci_handle);
15 }
16 
17 struct vmci_handle_arr *vmci_handle_arr_create(u32 capacity, u32 max_capacity)
18 {
19 	struct vmci_handle_arr *array;
20 
21 	if (max_capacity == 0 || capacity > max_capacity)
22 		return NULL;
23 
24 	if (capacity == 0)
25 		capacity = min((u32)VMCI_HANDLE_ARRAY_DEFAULT_CAPACITY,
26 			       max_capacity);
27 
28 	array = kmalloc(handle_arr_calc_size(capacity), GFP_ATOMIC);
29 	if (!array)
30 		return NULL;
31 
32 	array->capacity = capacity;
33 	array->max_capacity = max_capacity;
34 	array->size = 0;
35 
36 	return array;
37 }
38 
39 void vmci_handle_arr_destroy(struct vmci_handle_arr *array)
40 {
41 	kfree(array);
42 }
43 
44 int vmci_handle_arr_append_entry(struct vmci_handle_arr **array_ptr,
45 				 struct vmci_handle handle)
46 {
47 	struct vmci_handle_arr *array = *array_ptr;
48 
49 	if (unlikely(array->size >= array->capacity)) {
50 		/* reallocate. */
51 		struct vmci_handle_arr *new_array;
52 		u32 capacity_bump = min(array->max_capacity - array->capacity,
53 					array->capacity);
54 		size_t new_size = handle_arr_calc_size(array->capacity +
55 						       capacity_bump);
56 
57 		if (array->size >= array->max_capacity)
58 			return VMCI_ERROR_NO_MEM;
59 
60 		new_array = krealloc(array, new_size, GFP_ATOMIC);
61 		if (!new_array)
62 			return VMCI_ERROR_NO_MEM;
63 
64 		new_array->capacity += capacity_bump;
65 		*array_ptr = array = new_array;
66 	}
67 
68 	array->entries[array->size] = handle;
69 	array->size++;
70 
71 	return VMCI_SUCCESS;
72 }
73 
74 /*
75  * Handle that was removed, VMCI_INVALID_HANDLE if entry not found.
76  */
77 struct vmci_handle vmci_handle_arr_remove_entry(struct vmci_handle_arr *array,
78 						struct vmci_handle entry_handle)
79 {
80 	struct vmci_handle handle = VMCI_INVALID_HANDLE;
81 	u32 i;
82 
83 	for (i = 0; i < array->size; i++) {
84 		if (vmci_handle_is_equal(array->entries[i], entry_handle)) {
85 			handle = array->entries[i];
86 			array->size--;
87 			array->entries[i] = array->entries[array->size];
88 			array->entries[array->size] = VMCI_INVALID_HANDLE;
89 			break;
90 		}
91 	}
92 
93 	return handle;
94 }
95 
96 /*
97  * Handle that was removed, VMCI_INVALID_HANDLE if array was empty.
98  */
99 struct vmci_handle vmci_handle_arr_remove_tail(struct vmci_handle_arr *array)
100 {
101 	struct vmci_handle handle = VMCI_INVALID_HANDLE;
102 
103 	if (array->size) {
104 		array->size--;
105 		handle = array->entries[array->size];
106 		array->entries[array->size] = VMCI_INVALID_HANDLE;
107 	}
108 
109 	return handle;
110 }
111 
112 /*
113  * Handle at given index, VMCI_INVALID_HANDLE if invalid index.
114  */
115 struct vmci_handle
116 vmci_handle_arr_get_entry(const struct vmci_handle_arr *array, u32 index)
117 {
118 	if (unlikely(index >= array->size))
119 		return VMCI_INVALID_HANDLE;
120 
121 	return array->entries[index];
122 }
123 
124 bool vmci_handle_arr_has_entry(const struct vmci_handle_arr *array,
125 			       struct vmci_handle entry_handle)
126 {
127 	u32 i;
128 
129 	for (i = 0; i < array->size; i++)
130 		if (vmci_handle_is_equal(array->entries[i], entry_handle))
131 			return true;
132 
133 	return false;
134 }
135 
136 /*
137  * NULL if the array is empty. Otherwise, a pointer to the array
138  * of VMCI handles in the handle array.
139  */
140 struct vmci_handle *vmci_handle_arr_get_handles(struct vmci_handle_arr *array)
141 {
142 	if (array->size)
143 		return array->entries;
144 
145 	return NULL;
146 }
147