kernel/drivers/misc/vmw_vmci/vmci_handle_array.c

   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 }