mirror of https://github.com/Qortal/Brooklyn
You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
111 lines
3.2 KiB
111 lines
3.2 KiB
/* |
|
* Copyright (c) 2011 Chelsio Communications. All rights reserved. |
|
* |
|
* This software is available to you under a choice of one of two |
|
* licenses. You may choose to be licensed under the terms of the GNU |
|
* General Public License (GPL) Version 2, available from the file |
|
* COPYING in the main directory of this source tree, or the |
|
* OpenIB.org BSD license below: |
|
* |
|
* Redistribution and use in source and binary forms, with or |
|
* without modification, are permitted provided that the following |
|
* conditions are met: |
|
* |
|
* - Redistributions of source code must retain the above |
|
* copyright notice, this list of conditions and the following |
|
* disclaimer. |
|
* |
|
* - Redistributions in binary form must reproduce the above |
|
* copyright notice, this list of conditions and the following |
|
* disclaimer in the documentation and/or other materials |
|
* provided with the distribution. |
|
* |
|
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, |
|
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF |
|
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND |
|
* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS |
|
* BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN |
|
* ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN |
|
* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE |
|
* SOFTWARE. |
|
*/ |
|
#include <linux/kernel.h> |
|
#include <linux/random.h> |
|
#include "iw_cxgb4.h" |
|
|
|
#define RANDOM_SKIP 16 |
|
|
|
/* |
|
* Trivial bitmap-based allocator. If the random flag is set, the |
|
* allocator is designed to: |
|
* - pseudo-randomize the id returned such that it is not trivially predictable. |
|
* - avoid reuse of recently used id (at the expense of predictability) |
|
*/ |
|
u32 c4iw_id_alloc(struct c4iw_id_table *alloc) |
|
{ |
|
unsigned long flags; |
|
u32 obj; |
|
|
|
spin_lock_irqsave(&alloc->lock, flags); |
|
|
|
obj = find_next_zero_bit(alloc->table, alloc->max, alloc->last); |
|
if (obj >= alloc->max) |
|
obj = find_first_zero_bit(alloc->table, alloc->max); |
|
|
|
if (obj < alloc->max) { |
|
if (alloc->flags & C4IW_ID_TABLE_F_RANDOM) |
|
alloc->last += prandom_u32() % RANDOM_SKIP; |
|
else |
|
alloc->last = obj + 1; |
|
if (alloc->last >= alloc->max) |
|
alloc->last = 0; |
|
set_bit(obj, alloc->table); |
|
obj += alloc->start; |
|
} else |
|
obj = -1; |
|
|
|
spin_unlock_irqrestore(&alloc->lock, flags); |
|
return obj; |
|
} |
|
|
|
void c4iw_id_free(struct c4iw_id_table *alloc, u32 obj) |
|
{ |
|
unsigned long flags; |
|
|
|
obj -= alloc->start; |
|
|
|
spin_lock_irqsave(&alloc->lock, flags); |
|
clear_bit(obj, alloc->table); |
|
spin_unlock_irqrestore(&alloc->lock, flags); |
|
} |
|
|
|
int c4iw_id_table_alloc(struct c4iw_id_table *alloc, u32 start, u32 num, |
|
u32 reserved, u32 flags) |
|
{ |
|
int i; |
|
|
|
alloc->start = start; |
|
alloc->flags = flags; |
|
if (flags & C4IW_ID_TABLE_F_RANDOM) |
|
alloc->last = prandom_u32() % RANDOM_SKIP; |
|
else |
|
alloc->last = 0; |
|
alloc->max = num; |
|
spin_lock_init(&alloc->lock); |
|
alloc->table = kmalloc_array(BITS_TO_LONGS(num), sizeof(long), |
|
GFP_KERNEL); |
|
if (!alloc->table) |
|
return -ENOMEM; |
|
|
|
bitmap_zero(alloc->table, num); |
|
if (!(alloc->flags & C4IW_ID_TABLE_F_EMPTY)) |
|
for (i = 0; i < reserved; ++i) |
|
set_bit(i, alloc->table); |
|
|
|
return 0; |
|
} |
|
|
|
void c4iw_id_table_free(struct c4iw_id_table *alloc) |
|
{ |
|
kfree(alloc->table); |
|
}
|
|
|