linux/net/llc/llc_proc.c
Octavian Purdila b76f5a8427 llc: convert the socket list to RCU locking
For the reclamation phase we use the SLAB_DESTROY_BY_RCU mechanism,
which require some extra checks in the lookup code:

a) If the current socket was released, reallocated & inserted in
another list it will short circuit the iteration for the current list,
thus we need to restart the lookup.

b) If the current socket was released, reallocated & inserted in the
same list we just need to recheck it matches the look-up criteria and
if not we can skip to the next element.

In this case there is no need to restart the lookup, since sockets are
inserted at the start of the list and the worst that will happen is
that we will iterate throught some of the list elements more then
once.

Note that the /proc and multicast delivery was not yet converted to
RCU, it still uses spinlocks for protection.

Signed-off-by: Octavian Purdila <opurdila@ixiacom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2009-12-26 20:41:43 -08:00

264 lines
6.3 KiB
C

/*
* proc_llc.c - proc interface for LLC
*
* Copyright (c) 2001 by Jay Schulist <jschlst@samba.org>
* 2002-2003 by Arnaldo Carvalho de Melo <acme@conectiva.com.br>
*
* This program can be redistributed or modified under the terms of the
* GNU General Public License as published by the Free Software Foundation.
* This program is distributed without any warranty or implied warranty
* of merchantability or fitness for a particular purpose.
*
* See the GNU General Public License for more details.
*/
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/proc_fs.h>
#include <linux/errno.h>
#include <linux/seq_file.h>
#include <net/net_namespace.h>
#include <net/sock.h>
#include <net/llc.h>
#include <net/llc_c_ac.h>
#include <net/llc_c_ev.h>
#include <net/llc_c_st.h>
#include <net/llc_conn.h>
static void llc_ui_format_mac(struct seq_file *seq, u8 *addr)
{
seq_printf(seq, "%pM", addr);
}
static struct sock *llc_get_sk_idx(loff_t pos)
{
struct list_head *sap_entry;
struct llc_sap *sap;
struct hlist_nulls_node *node;
struct sock *sk = NULL;
list_for_each(sap_entry, &llc_sap_list) {
sap = list_entry(sap_entry, struct llc_sap, node);
spin_lock_bh(&sap->sk_lock);
sk_nulls_for_each(sk, node, &sap->sk_list) {
if (!pos)
goto found;
--pos;
}
spin_unlock_bh(&sap->sk_lock);
}
sk = NULL;
found:
return sk;
}
static void *llc_seq_start(struct seq_file *seq, loff_t *pos)
{
loff_t l = *pos;
read_lock_bh(&llc_sap_list_lock);
return l ? llc_get_sk_idx(--l) : SEQ_START_TOKEN;
}
static void *llc_seq_next(struct seq_file *seq, void *v, loff_t *pos)
{
struct sock* sk, *next;
struct llc_sock *llc;
struct llc_sap *sap;
++*pos;
if (v == SEQ_START_TOKEN) {
sk = llc_get_sk_idx(0);
goto out;
}
sk = v;
next = sk_nulls_next(sk);
if (next) {
sk = next;
goto out;
}
llc = llc_sk(sk);
sap = llc->sap;
spin_unlock_bh(&sap->sk_lock);
sk = NULL;
for (;;) {
if (sap->node.next == &llc_sap_list)
break;
sap = list_entry(sap->node.next, struct llc_sap, node);
spin_lock_bh(&sap->sk_lock);
if (!hlist_nulls_empty(&sap->sk_list)) {
sk = sk_nulls_head(&sap->sk_list);
break;
}
spin_unlock_bh(&sap->sk_lock);
}
out:
return sk;
}
static void llc_seq_stop(struct seq_file *seq, void *v)
{
if (v && v != SEQ_START_TOKEN) {
struct sock *sk = v;
struct llc_sock *llc = llc_sk(sk);
struct llc_sap *sap = llc->sap;
spin_unlock_bh(&sap->sk_lock);
}
read_unlock_bh(&llc_sap_list_lock);
}
static int llc_seq_socket_show(struct seq_file *seq, void *v)
{
struct sock* sk;
struct llc_sock *llc;
if (v == SEQ_START_TOKEN) {
seq_puts(seq, "SKt Mc local_mac_sap remote_mac_sap "
" tx_queue rx_queue st uid link\n");
goto out;
}
sk = v;
llc = llc_sk(sk);
/* FIXME: check if the address is multicast */
seq_printf(seq, "%2X %2X ", sk->sk_type, 0);
if (llc->dev)
llc_ui_format_mac(seq, llc->dev->dev_addr);
else {
u8 addr[6] = {0,0,0,0,0,0};
llc_ui_format_mac(seq, addr);
}
seq_printf(seq, "@%02X ", llc->sap->laddr.lsap);
llc_ui_format_mac(seq, llc->daddr.mac);
seq_printf(seq, "@%02X %8d %8d %2d %3d %4d\n", llc->daddr.lsap,
sk_wmem_alloc_get(sk),
sk_rmem_alloc_get(sk) - llc->copied_seq,
sk->sk_state,
sk->sk_socket ? SOCK_INODE(sk->sk_socket)->i_uid : -1,
llc->link);
out:
return 0;
}
static const char *const llc_conn_state_names[] = {
[LLC_CONN_STATE_ADM] = "adm",
[LLC_CONN_STATE_SETUP] = "setup",
[LLC_CONN_STATE_NORMAL] = "normal",
[LLC_CONN_STATE_BUSY] = "busy",
[LLC_CONN_STATE_REJ] = "rej",
[LLC_CONN_STATE_AWAIT] = "await",
[LLC_CONN_STATE_AWAIT_BUSY] = "await_busy",
[LLC_CONN_STATE_AWAIT_REJ] = "await_rej",
[LLC_CONN_STATE_D_CONN] = "d_conn",
[LLC_CONN_STATE_RESET] = "reset",
[LLC_CONN_STATE_ERROR] = "error",
[LLC_CONN_STATE_TEMP] = "temp",
};
static int llc_seq_core_show(struct seq_file *seq, void *v)
{
struct sock* sk;
struct llc_sock *llc;
if (v == SEQ_START_TOKEN) {
seq_puts(seq, "Connection list:\n"
"dsap state retr txw rxw pf ff sf df rs cs "
"tack tpfc trs tbs blog busr\n");
goto out;
}
sk = v;
llc = llc_sk(sk);
seq_printf(seq, " %02X %-10s %3d %3d %3d %2d %2d %2d %2d %2d %2d "
"%4d %4d %3d %3d %4d %4d\n",
llc->daddr.lsap, llc_conn_state_names[llc->state],
llc->retry_count, llc->k, llc->rw, llc->p_flag, llc->f_flag,
llc->s_flag, llc->data_flag, llc->remote_busy_flag,
llc->cause_flag, timer_pending(&llc->ack_timer.timer),
timer_pending(&llc->pf_cycle_timer.timer),
timer_pending(&llc->rej_sent_timer.timer),
timer_pending(&llc->busy_state_timer.timer),
!!sk->sk_backlog.tail, !!sock_owned_by_user(sk));
out:
return 0;
}
static const struct seq_operations llc_seq_socket_ops = {
.start = llc_seq_start,
.next = llc_seq_next,
.stop = llc_seq_stop,
.show = llc_seq_socket_show,
};
static const struct seq_operations llc_seq_core_ops = {
.start = llc_seq_start,
.next = llc_seq_next,
.stop = llc_seq_stop,
.show = llc_seq_core_show,
};
static int llc_seq_socket_open(struct inode *inode, struct file *file)
{
return seq_open(file, &llc_seq_socket_ops);
}
static int llc_seq_core_open(struct inode *inode, struct file *file)
{
return seq_open(file, &llc_seq_core_ops);
}
static const struct file_operations llc_seq_socket_fops = {
.owner = THIS_MODULE,
.open = llc_seq_socket_open,
.read = seq_read,
.llseek = seq_lseek,
.release = seq_release,
};
static const struct file_operations llc_seq_core_fops = {
.owner = THIS_MODULE,
.open = llc_seq_core_open,
.read = seq_read,
.llseek = seq_lseek,
.release = seq_release,
};
static struct proc_dir_entry *llc_proc_dir;
int __init llc_proc_init(void)
{
int rc = -ENOMEM;
struct proc_dir_entry *p;
llc_proc_dir = proc_mkdir("llc", init_net.proc_net);
if (!llc_proc_dir)
goto out;
p = proc_create("socket", S_IRUGO, llc_proc_dir, &llc_seq_socket_fops);
if (!p)
goto out_socket;
p = proc_create("core", S_IRUGO, llc_proc_dir, &llc_seq_core_fops);
if (!p)
goto out_core;
rc = 0;
out:
return rc;
out_core:
remove_proc_entry("socket", llc_proc_dir);
out_socket:
remove_proc_entry("llc", init_net.proc_net);
goto out;
}
void llc_proc_exit(void)
{
remove_proc_entry("socket", llc_proc_dir);
remove_proc_entry("core", llc_proc_dir);
remove_proc_entry("llc", init_net.proc_net);
}