drivers/infiniband/hw/mthca/mthca_allocator.c

   1 /*
   2  * Copyright (c) 2004 Topspin Communications.  All rights reserved.
   3  *
   4  * This software is available to you under a choice of one of two
   5  * licenses.  You may choose to be licensed under the terms of the GNU
   6  * General Public License (GPL) Version 2, available from the file
   7  * COPYING in the main directory of this source tree, or the
   8  * OpenIB.org BSD license below:
   9  *
  10  *     Redistribution and use in source and binary forms, with or
  11  *     without modification, are permitted provided that the following
  12  *     conditions are met:
  13  *
  14  *      - Redistributions of source code must retain the above
  15  *        copyright notice, this list of conditions and the following
  16  *        disclaimer.
  17  *
  18  *      - Redistributions in binary form must reproduce the above
  19  *        copyright notice, this list of conditions and the following
  20  *        disclaimer in the documentation and/or other materials
  21  *        provided with the distribution.
  22  *
  23  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  24  * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  25  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  26  * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
  27  * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
  28  * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
  29  * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  30  * SOFTWARE.
  31  *
  32  * $Id: mthca_allocator.c 1349 2004-12-16 21:09:43Z roland $
  33  */
  34
  35 #include <linux/errno.h>
  36 #include <linux/slab.h>
  37 #include <linux/bitmap.h>
  38
  39 #include "mthca_dev.h"
  40
  41 /* Trivial bitmap-based allocator */
  42 u32 mthca_alloc(struct mthca_alloc *alloc)
  43 {
  44         u32 obj;
  45
  46         spin_lock(&alloc->lock);
  47         obj = find_next_zero_bit(alloc->table, alloc->max, alloc->last);
  48         if (obj >= alloc->max) {
  49                 alloc->top = (alloc->top + alloc->max) & alloc->mask;
  50                 obj = find_first_zero_bit(alloc->table, alloc->max);
  51         }
  52
  53         if (obj < alloc->max) {
  54                 set_bit(obj, alloc->table);
  55                 obj |= alloc->top;
  56         } else
  57                 obj = -1;
  58
  59         spin_unlock(&alloc->lock);
  60
  61         return obj;
  62 }
  63
  64 void mthca_free(struct mthca_alloc *alloc, u32 obj)
  65 {
  66         obj &= alloc->max - 1;
  67         spin_lock(&alloc->lock);
  68         clear_bit(obj, alloc->table);
  69         alloc->last = min(alloc->last, obj);
  70         alloc->top = (alloc->top + alloc->max) & alloc->mask;
  71         spin_unlock(&alloc->lock);
  72 }
  73
  74 int mthca_alloc_init(struct mthca_alloc *alloc, u32 num, u32 mask,
  75                      u32 reserved)
  76 {
  77         int i;
  78
  79         /* num must be a power of 2 */
  80         if (num != 1 << (ffs(num) - 1))
  81                 return -EINVAL;
  82
  83         alloc->last = 0;
  84         alloc->top  = 0;
  85         alloc->max  = num;
  86         alloc->mask = mask;
  87         spin_lock_init(&alloc->lock);
  88         alloc->table = kmalloc(BITS_TO_LONGS(num) * sizeof (long),
  89                                GFP_KERNEL);
  90         if (!alloc->table)
  91                 return -ENOMEM;
  92
  93         bitmap_zero(alloc->table, num);
  94         for (i = 0; i < reserved; ++i)
  95                 set_bit(i, alloc->table);
  96
  97         return 0;
  98 }
  99
 100 void mthca_alloc_cleanup(struct mthca_alloc *alloc)
 101 {
 102         kfree(alloc->table);
 103 }
 104
 105 /*
 106  * Array of pointers with lazy allocation of leaf pages.  Callers of
 107  * _get, _set and _clear methods must use a lock or otherwise
 108  * serialize access to the array.
 109  */
 110
 111 void *mthca_array_get(struct mthca_array *array, int index)
 112 {
 113         int p = (index * sizeof (void *)) >> PAGE_SHIFT;
 114
 115         if (array->page_list[p].page) {
 116                 int i = index & (PAGE_SIZE / sizeof (void *) - 1);
 117                 return array->page_list[p].page[i];
 118         } else
 119                 return NULL;
 120 }
 121
 122 int mthca_array_set(struct mthca_array *array, int index, void *value)
 123 {
 124         int p = (index * sizeof (void *)) >> PAGE_SHIFT;
 125
 126         /* Allocate with GFP_ATOMIC because we'll be called with locks held. */
 127         if (!array->page_list[p].page)
 128                 array->page_list[p].page = (void **) get_zeroed_page(GFP_ATOMIC);
 129
 130         if (!array->page_list[p].page)
 131                 return -ENOMEM;
 132
 133         array->page_list[p].page[index & (PAGE_SIZE / sizeof (void *) - 1)] =
 134                 value;
 135         ++array->page_list[p].used;
 136
 137         return 0;
 138 }
 139
 140 void mthca_array_clear(struct mthca_array *array, int index)
 141 {
 142         int p = (index * sizeof (void *)) >> PAGE_SHIFT;
 143
 144         if (--array->page_list[p].used == 0) {
 145                 free_page((unsigned long) array->page_list[p].page);
 146                 array->page_list[p].page = NULL;
 147         }
 148
 149         if (array->page_list[p].used < 0)
 150                 pr_debug("Array %p index %d page %d with ref count %d < 0\n",
 151                          array, index, p, array->page_list[p].used);
 152 }
 153
 154 int mthca_array_init(struct mthca_array *array, int nent)
 155 {
 156         int npage = (nent * sizeof (void *) + PAGE_SIZE - 1) / PAGE_SIZE;
 157         int i;
 158
 159         array->page_list = kmalloc(npage * sizeof *array->page_list, GFP_KERNEL);
 160         if (!array->page_list)
 161                 return -ENOMEM;
 162
 163         for (i = 0; i < npage; ++i) {
 164                 array->page_list[i].page = NULL;
 165                 array->page_list[i].used = 0;
 166         }
 167
 168         return 0;
 169 }
 170
 171 void mthca_array_cleanup(struct mthca_array *array, int nent)
 172 {
 173         int i;
 174
 175         for (i = 0; i < (nent * sizeof (void *) + PAGE_SIZE - 1) / PAGE_SIZE; ++i)
 176                 free_page((unsigned long) array->page_list[i].page);
 177
 178         kfree(array->page_list);
 179 }