1 /*- 2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD 3 * 4 * Copyright (c) 2011-2013 Chelsio Communications. All rights reserved. 5 * 6 * This software is available to you under a choice of one of two 7 * licenses. You may choose to be licensed under the terms of the GNU 8 * General Public License (GPL) Version 2, available from the file 9 * COPYING in the main directory of this source tree, or the 10 * OpenIB.org BSD license below: 11 * 12 * Redistribution and use in source and binary forms, with or 13 * without modification, are permitted provided that the following 14 * conditions are met: 15 * 16 * - Redistributions of source code must retain the above 17 * copyright notice, this list of conditions and the following 18 * disclaimer. 19 * 20 * - Redistributions in binary form must reproduce the above 21 * copyright notice, this list of conditions and the following 22 * disclaimer in the documentation and/or other materials 23 * provided with the distribution. 24 * 25 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, 26 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF 27 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND 28 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS 29 * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN 30 * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN 31 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE 32 * SOFTWARE. 33 */ 34 #include <sys/cdefs.h> 35 __FBSDID("$FreeBSD$"); 36 37 #include "opt_inet.h" 38 39 #ifdef TCP_OFFLOAD 40 #include <sys/libkern.h> 41 #include "iw_cxgbe.h" 42 43 #define RANDOM_SKIP 16 44 45 /* 46 * Trivial bitmap-based allocator. If the random flag is set, the 47 * allocator is designed to: 48 * - pseudo-randomize the id returned such that it is not trivially predictable. 49 * - avoid reuse of recently used id (at the expense of predictability) 50 */ 51 u32 c4iw_id_alloc(struct c4iw_id_table *alloc) 52 { 53 unsigned long flags; 54 u32 obj; 55 56 spin_lock_irqsave(&alloc->lock, flags); 57 58 obj = find_next_zero_bit(alloc->table, alloc->max, alloc->last); 59 if (obj >= alloc->max) 60 obj = find_first_zero_bit(alloc->table, alloc->max); 61 62 if (obj < alloc->max) { 63 if (alloc->flags & C4IW_ID_TABLE_F_RANDOM) 64 alloc->last += arc4random() % RANDOM_SKIP; 65 else 66 alloc->last = obj + 1; 67 if (alloc->last >= alloc->max) 68 alloc->last = 0; 69 set_bit(obj, alloc->table); 70 obj += alloc->start; 71 } else 72 obj = -1; 73 74 spin_unlock_irqrestore(&alloc->lock, flags); 75 return obj; 76 } 77 78 void c4iw_id_free(struct c4iw_id_table *alloc, u32 obj) 79 { 80 unsigned long flags; 81 82 obj -= alloc->start; 83 BUG_ON((int)obj < 0); 84 85 spin_lock_irqsave(&alloc->lock, flags); 86 clear_bit(obj, alloc->table); 87 spin_unlock_irqrestore(&alloc->lock, flags); 88 } 89 90 int c4iw_id_table_alloc(struct c4iw_id_table *alloc, u32 start, u32 num, 91 u32 reserved, u32 flags) 92 { 93 int i; 94 95 alloc->start = start; 96 alloc->flags = flags; 97 if (flags & C4IW_ID_TABLE_F_RANDOM) 98 alloc->last = arc4random() % RANDOM_SKIP; 99 else 100 alloc->last = 0; 101 alloc->max = num; 102 spin_lock_init(&alloc->lock); 103 alloc->table = kmalloc(BITS_TO_LONGS(num) * sizeof(long), 104 GFP_KERNEL); 105 if (!alloc->table) 106 return -ENOMEM; 107 108 bitmap_zero(alloc->table, num); 109 if (!(alloc->flags & C4IW_ID_TABLE_F_EMPTY)) 110 for (i = 0; i < reserved; ++i) 111 set_bit(i, alloc->table); 112 113 return 0; 114 } 115 116 void c4iw_id_table_free(struct c4iw_id_table *alloc) 117 { 118 kfree(alloc->table); 119 } 120 #endif 121