102 lines
3.1 KiB
C
102 lines
3.1 KiB
C
/*
|
|
include/proto/port_range.h
|
|
This file defines everything needed to manage port ranges
|
|
|
|
Copyright (C) 2000-2009 Willy Tarreau - w@1wt.eu
|
|
|
|
This library is free software; you can redistribute it and/or
|
|
modify it under the terms of the GNU Lesser General Public
|
|
License as published by the Free Software Foundation, version 2.1
|
|
exclusively.
|
|
|
|
This library is distributed in the hope that it will be useful,
|
|
but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
|
|
Lesser General Public License for more details.
|
|
|
|
You should have received a copy of the GNU Lesser General Public
|
|
License along with this library; if not, write to the Free Software
|
|
Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
|
|
*/
|
|
|
|
#ifndef _PROTO_PORT_RANGE_H
|
|
#define _PROTO_PORT_RANGE_H
|
|
|
|
#include <types/port_range.h>
|
|
|
|
#define GET_NEXT_OFF(range, off) ((off) == (range)->size - 1 ? 0 : (off) + 1)
|
|
|
|
/* return an available port from range <range>, or zero if none is left */
|
|
static inline int port_range_alloc_port(struct port_range *range)
|
|
{
|
|
int ret;
|
|
int get;
|
|
int put;
|
|
|
|
get = _HA_ATOMIC_LOAD(&range->get);
|
|
do {
|
|
/* barrier ot make sure get is loaded before put */
|
|
__ha_barrier_atomic_load();
|
|
put = _HA_ATOMIC_LOAD(&range->put_t);
|
|
if (unlikely(put == get))
|
|
return 0;
|
|
ret = range->ports[get];
|
|
} while (!(_HA_ATOMIC_CAS(&range->get, &get, GET_NEXT_OFF(range, get))));
|
|
return ret;
|
|
}
|
|
|
|
/* release port <port> into port range <range>. Does nothing if <port> is zero
|
|
* nor if <range> is null. The caller is responsible for marking the port
|
|
* unused by either setting the port to zero or the range to NULL.
|
|
*/
|
|
static inline void port_range_release_port(struct port_range *range, int port)
|
|
{
|
|
int put;
|
|
|
|
if (!port || !range)
|
|
return;
|
|
|
|
put = range->put_h;
|
|
/* put_h is reserved for producers, so that they can each get a
|
|
* free slot, put_t is what is used by consumers to know if there's
|
|
* elements available or not
|
|
*/
|
|
/* First reserve or slot, we know the ring buffer can't be full,
|
|
* as we will only ever release port we allocated before
|
|
*/
|
|
while (!(_HA_ATOMIC_CAS(&range->put_h, &put, GET_NEXT_OFF(range, put))));
|
|
_HA_ATOMIC_STORE(&range->ports[put], port);
|
|
/* Barrier to make sure the new port is visible before we change put_t */
|
|
__ha_barrier_atomic_store();
|
|
/* Wait until all the threads that got a slot before us are done */
|
|
while ((volatile int)range->put_t != put)
|
|
__ha_compiler_barrier();
|
|
/* Let the world know we're done, and any potential consumer they
|
|
* can use that port.
|
|
*/
|
|
_HA_ATOMIC_STORE(&range->put_t, GET_NEXT_OFF(range, put));
|
|
}
|
|
|
|
/* return a new initialized port range of N ports. The ports are not
|
|
* filled in, it's up to the caller to do it.
|
|
*/
|
|
static inline struct port_range *port_range_alloc_range(int n)
|
|
{
|
|
struct port_range *ret;
|
|
ret = calloc(1, sizeof(struct port_range) +
|
|
(n + 1) * sizeof(((struct port_range *)0)->ports[0]));
|
|
ret->size = n + 1;
|
|
/* Start at the first free element */
|
|
ret->put_h = ret->put_t = n;
|
|
return ret;
|
|
}
|
|
|
|
#endif /* _PROTO_PORT_RANGE_H */
|
|
|
|
/*
|
|
* Local variables:
|
|
* c-indent-level: 8
|
|
* c-basic-offset: 8
|
|
* End:
|
|
*/
|