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(u32 capacity)
  20 {
  21         return VMCI_HANDLE_ARRAY_HEADER_SIZE +
  22             capacity * sizeof(struct vmci_handle);
  23 }
  24
  25 struct vmci_handle_arr *vmci_handle_arr_create(u32 capacity, u32 max_capacity)
  26 {
  27         struct vmci_handle_arr *array;
  28
  29         if (max_capacity == 0 || capacity > max_capacity)
  30                 return NULL;
  31
  32         if (capacity == 0)
  33                 capacity = min((u32)VMCI_HANDLE_ARRAY_DEFAULT_CAPACITY,
  34                                max_capacity);
  35
  36         array = kmalloc(handle_arr_calc_size(capacity), GFP_ATOMIC);
  37         if (!array)
  38                 return NULL;
  39
  40         array->capacity = capacity;
  41         array->max_capacity = max_capacity;
  42         array->size = 0;
  43
  44         return array;
  45 }
  46
  47 void vmci_handle_arr_destroy(struct vmci_handle_arr *array)
  48 {
  49         kfree(array);
  50 }
  51
  52 int vmci_handle_arr_append_entry(struct vmci_handle_arr **array_ptr,
  53                                  struct vmci_handle handle)
  54 {
  55         struct vmci_handle_arr *array = *array_ptr;
  56
  57         if (unlikely(array->size >= array->capacity)) {
  58                 /* reallocate. */
  59                 struct vmci_handle_arr *new_array;
  60                 u32 capacity_bump = min(array->max_capacity - array->capacity,
  61                                         array->capacity);
  62                 size_t new_size = handle_arr_calc_size(array->capacity +
  63                                                        capacity_bump);
  64
  65                 if (array->size >= array->max_capacity)
  66                         return VMCI_ERROR_NO_MEM;
  67
  68                 new_array = krealloc(array, new_size, GFP_ATOMIC);
  69                 if (!new_array)
  70                         return VMCI_ERROR_NO_MEM;
  71
  72                 new_array->capacity += capacity_bump;
  73                 *array_ptr = array = new_array;
  74         }
  75
  76         array->entries[array->size] = handle;
  77         array->size++;
  78
  79         return VMCI_SUCCESS;
  80 }
  81
  82 /*
  83  * Handle that was removed, VMCI_INVALID_HANDLE if entry not found.
  84  */
  85 struct vmci_handle vmci_handle_arr_remove_entry(struct vmci_handle_arr *array,
  86                                                 struct vmci_handle entry_handle)
  87 {
  88         struct vmci_handle handle = VMCI_INVALID_HANDLE;
  89         u32 i;
  90
  91         for (i = 0; i < array->size; i++) {
  92                 if (vmci_handle_is_equal(array->entries[i], entry_handle)) {
  93                         handle = array->entries[i];
  94                         array->size--;
  95                         array->entries[i] = array->entries[array->size];
  96                         array->entries[array->size] = VMCI_INVALID_HANDLE;
  97                         break;
  98                 }
  99         }
 100
 101         return handle;
 102 }
 103
 104 /*
 105  * Handle that was removed, VMCI_INVALID_HANDLE if array was empty.
 106  */
 107 struct vmci_handle vmci_handle_arr_remove_tail(struct vmci_handle_arr *array)
 108 {
 109         struct vmci_handle handle = VMCI_INVALID_HANDLE;
 110
 111         if (array->size) {
 112                 array->size--;
 113                 handle = array->entries[array->size];
 114                 array->entries[array->size] = VMCI_INVALID_HANDLE;
 115         }
 116
 117         return handle;
 118 }
 119
 120 /*
 121  * Handle at given index, VMCI_INVALID_HANDLE if invalid index.
 122  */
 123 struct vmci_handle
 124 vmci_handle_arr_get_entry(const struct vmci_handle_arr *array, u32 index)
 125 {
 126         if (unlikely(index >= array->size))
 127                 return VMCI_INVALID_HANDLE;
 128
 129         return array->entries[index];
 130 }
 131
 132 bool vmci_handle_arr_has_entry(const struct vmci_handle_arr *array,
 133                                struct vmci_handle entry_handle)
 134 {
 135         u32 i;
 136
 137         for (i = 0; i < array->size; i++)
 138                 if (vmci_handle_is_equal(array->entries[i], entry_handle))
 139                         return true;
 140
 141         return false;
 142 }
 143
 144 /*
 145  * NULL if the array is empty. Otherwise, a pointer to the array
 146  * of VMCI handles in the handle array.
 147  */
 148 struct vmci_handle *vmci_handle_arr_get_handles(struct vmci_handle_arr *array)
 149 {
 150         if (array->size)
 151                 return array->entries;
 152
 153         return NULL;
 154 }