freebsd-dev/sys/dev/cxgbe/iw_cxgbe/id_table.c
Pedro F. Giffuni 718cf2ccb9 sys/dev: further adoption of SPDX licensing ID tags.
Mainly focus on files that use BSD 2-Clause license, however the tool I
was using misidentified many licenses so this was mostly a manual - error
prone - task.

The Software Package Data Exchange (SPDX) group provides a specification
to make it easier for automated tools to detect and summarize well known
opensource licenses. We are gradually adopting the specification, noting
that the tags are considered only advisory and do not, in any way,
superceed or replace the license texts.
2017-11-27 14:52:40 +00:00

121 lines
3.4 KiB
C

/*-
* SPDX-License-Identifier: BSD-2-Clause-FreeBSD
*
* Copyright (c) 2011-2013 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 <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include "opt_inet.h"
#ifdef TCP_OFFLOAD
#include <sys/libkern.h>
#include "iw_cxgbe.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 += arc4random() % 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;
BUG_ON((int)obj < 0);
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 = arc4random() % RANDOM_SKIP;
else
alloc->last = 0;
alloc->max = num;
spin_lock_init(&alloc->lock);
alloc->table = kmalloc(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);
}
#endif