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l2tp: fix locking of 64-bit counters for smp
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L2TP uses 64-bit counters but since these are not updated atomically,
we need to make them safe for smp. This patch addresses that.

Signed-off-by: James Chapman <[email protected]>
Signed-off-by: David S. Miller <[email protected]>
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@j-c-h @davem330
j-c-h authored and davem330 committed May 1, 2012
1 parent 80bcb42 commit 5de7aee
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Showing 3 changed files with 103 additions and 35 deletions.
75 changes: 56 additions & 19 deletions net/l2tp/l2tp_core.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -330,16 +330,20 @@ static void l2tp_recv_queue_skb(struct l2tp_session *session, struct sk_buff *sk
struct sk_buff *skbp;
struct sk_buff *tmp;
u32 ns = L2TP_SKB_CB(skb)->ns;
struct l2tp_stats *sstats;

spin_lock_bh(&session->reorder_q.lock);
sstats = &session->stats;
skb_queue_walk_safe(&session->reorder_q, skbp, tmp) {
if (L2TP_SKB_CB(skbp)->ns > ns) {
__skb_queue_before(&session->reorder_q, skbp, skb);
PRINTK(session->debug, L2TP_MSG_SEQ, KERN_DEBUG,
"%s: pkt %hu, inserted before %hu, reorder_q len=%d\n",
session->name, ns, L2TP_SKB_CB(skbp)->ns,
skb_queue_len(&session->reorder_q));
session->stats.rx_oos_packets++;
u64_stats_update_begin(&sstats->syncp);
sstats->rx_oos_packets++;
u64_stats_update_end(&sstats->syncp);
goto out;
}
}
Expand All @@ -356,16 +360,23 @@ static void l2tp_recv_dequeue_skb(struct l2tp_session *session, struct sk_buff *
{
struct l2tp_tunnel *tunnel = session->tunnel;
int length = L2TP_SKB_CB(skb)->length;
struct l2tp_stats *tstats, *sstats;

/* We're about to requeue the skb, so return resources
* to its current owner (a socket receive buffer).
*/
skb_orphan(skb);

tunnel->stats.rx_packets++;
tunnel->stats.rx_bytes += length;
session->stats.rx_packets++;
session->stats.rx_bytes += length;
tstats = &tunnel->stats;
u64_stats_update_begin(&tstats->syncp);
sstats = &session->stats;
u64_stats_update_begin(&sstats->syncp);
tstats->rx_packets++;
tstats->rx_bytes += length;
sstats->rx_packets++;
sstats->rx_bytes += length;
u64_stats_update_end(&tstats->syncp);
u64_stats_update_end(&sstats->syncp);

if (L2TP_SKB_CB(skb)->has_seq) {
/* Bump our Nr */
Expand Down Expand Up @@ -396,17 +407,21 @@ static void l2tp_recv_dequeue(struct l2tp_session *session)
{
struct sk_buff *skb;
struct sk_buff *tmp;
struct l2tp_stats *sstats;

/* If the pkt at the head of the queue has the nr that we
* expect to send up next, dequeue it and any other
* in-sequence packets behind it.
*/
start:
spin_lock_bh(&session->reorder_q.lock);
sstats = &session->stats;
skb_queue_walk_safe(&session->reorder_q, skb, tmp) {
if (time_after(jiffies, L2TP_SKB_CB(skb)->expires)) {
session->stats.rx_seq_discards++;
session->stats.rx_errors++;
u64_stats_update_begin(&sstats->syncp);
sstats->rx_seq_discards++;
sstats->rx_errors++;
u64_stats_update_end(&sstats->syncp);
PRINTK(session->debug, L2TP_MSG_SEQ, KERN_DEBUG,
"%s: oos pkt %u len %d discarded (too old), "
"waiting for %u, reorder_q_len=%d\n",
Expand Down Expand Up @@ -558,6 +573,7 @@ void l2tp_recv_common(struct l2tp_session *session, struct sk_buff *skb,
struct l2tp_tunnel *tunnel = session->tunnel;
int offset;
u32 ns, nr;
struct l2tp_stats *sstats = &session->stats;

/* The ref count is increased since we now hold a pointer to
* the session. Take care to decrement the refcnt when exiting
Expand All @@ -573,7 +589,9 @@ void l2tp_recv_common(struct l2tp_session *session, struct sk_buff *skb,
PRINTK(tunnel->debug, L2TP_MSG_DATA, KERN_INFO,
"%s: cookie mismatch (%u/%u). Discarding.\n",
tunnel->name, tunnel->tunnel_id, session->session_id);
session->stats.rx_cookie_discards++;
u64_stats_update_begin(&sstats->syncp);
sstats->rx_cookie_discards++;
u64_stats_update_end(&sstats->syncp);
goto discard;
}
ptr += session->peer_cookie_len;
Expand Down Expand Up @@ -642,7 +660,9 @@ void l2tp_recv_common(struct l2tp_session *session, struct sk_buff *skb,
PRINTK(session->debug, L2TP_MSG_SEQ, KERN_WARNING,
"%s: recv data has no seq numbers when required. "
"Discarding\n", session->name);
session->stats.rx_seq_discards++;
u64_stats_update_begin(&sstats->syncp);
sstats->rx_seq_discards++;
u64_stats_update_end(&sstats->syncp);
goto discard;
}

Expand All @@ -661,7 +681,9 @@ void l2tp_recv_common(struct l2tp_session *session, struct sk_buff *skb,
PRINTK(session->debug, L2TP_MSG_SEQ, KERN_WARNING,
"%s: recv data has no seq numbers when required. "
"Discarding\n", session->name);
session->stats.rx_seq_discards++;
u64_stats_update_begin(&sstats->syncp);
sstats->rx_seq_discards++;
u64_stats_update_end(&sstats->syncp);
goto discard;
}
}
Expand Down Expand Up @@ -715,7 +737,9 @@ void l2tp_recv_common(struct l2tp_session *session, struct sk_buff *skb,
* packets
*/
if (L2TP_SKB_CB(skb)->ns != session->nr) {
session->stats.rx_seq_discards++;
u64_stats_update_begin(&sstats->syncp);
sstats->rx_seq_discards++;
u64_stats_update_end(&sstats->syncp);
PRINTK(session->debug, L2TP_MSG_SEQ, KERN_DEBUG,
"%s: oos pkt %u len %d discarded, "
"waiting for %u, reorder_q_len=%d\n",
Expand All @@ -742,7 +766,9 @@ void l2tp_recv_common(struct l2tp_session *session, struct sk_buff *skb,
return;

discard:
session->stats.rx_errors++;
u64_stats_update_begin(&sstats->syncp);
sstats->rx_errors++;
u64_stats_update_end(&sstats->syncp);
kfree_skb(skb);

if (session->deref)
Expand All @@ -768,6 +794,7 @@ static int l2tp_udp_recv_core(struct l2tp_tunnel *tunnel, struct sk_buff *skb,
int offset;
u16 version;
int length;
struct l2tp_stats *tstats;

if (tunnel->sock && l2tp_verify_udp_checksum(tunnel->sock, skb))
goto discard_bad_csum;
Expand Down Expand Up @@ -860,7 +887,10 @@ static int l2tp_udp_recv_core(struct l2tp_tunnel *tunnel, struct sk_buff *skb,
discard_bad_csum:
LIMIT_NETDEBUG("%s: UDP: bad checksum\n", tunnel->name);
UDP_INC_STATS_USER(tunnel->l2tp_net, UDP_MIB_INERRORS, 0);
tunnel->stats.rx_errors++;
tstats = &tunnel->stats;
u64_stats_update_begin(&tstats->syncp);
tstats->rx_errors++;
u64_stats_update_end(&tstats->syncp);
kfree_skb(skb);

return 0;
Expand Down Expand Up @@ -986,6 +1016,7 @@ static int l2tp_xmit_core(struct l2tp_session *session, struct sk_buff *skb,
struct l2tp_tunnel *tunnel = session->tunnel;
unsigned int len = skb->len;
int error;
struct l2tp_stats *tstats, *sstats;

/* Debug */
if (session->send_seq)
Expand Down Expand Up @@ -1022,15 +1053,21 @@ static int l2tp_xmit_core(struct l2tp_session *session, struct sk_buff *skb,
error = ip_queue_xmit(skb, fl);

/* Update stats */
tstats = &tunnel->stats;
u64_stats_update_begin(&tstats->syncp);
sstats = &session->stats;
u64_stats_update_begin(&sstats->syncp);
if (error >= 0) {
tunnel->stats.tx_packets++;
tunnel->stats.tx_bytes += len;
session->stats.tx_packets++;
session->stats.tx_bytes += len;
tstats->tx_packets++;
tstats->tx_bytes += len;
sstats->tx_packets++;
sstats->tx_bytes += len;
} else {
tunnel->stats.tx_errors++;
session->stats.tx_errors++;
tstats->tx_errors++;
sstats->tx_errors++;
}
u64_stats_update_end(&tstats->syncp);
u64_stats_update_end(&sstats->syncp);

return 0;
}
Expand Down
1 change: 1 addition & 0 deletions net/l2tp/l2tp_core.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -45,6 +45,7 @@ struct l2tp_stats {
u64 rx_oos_packets;
u64 rx_errors;
u64 rx_cookie_discards;
struct u64_stats_sync syncp;
};

struct l2tp_tunnel;
Expand Down
62 changes: 46 additions & 16 deletions net/l2tp/l2tp_netlink.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -225,6 +225,8 @@ static int l2tp_nl_tunnel_send(struct sk_buff *skb, u32 pid, u32 seq, int flags,
struct nlattr *nest;
struct sock *sk = NULL;
struct inet_sock *inet;
struct l2tp_stats stats;
unsigned int start;

hdr = genlmsg_put(skb, pid, seq, &l2tp_nl_family, flags,
L2TP_CMD_TUNNEL_GET);
Expand All @@ -242,16 +244,28 @@ static int l2tp_nl_tunnel_send(struct sk_buff *skb, u32 pid, u32 seq, int flags,
if (nest == NULL)
goto nla_put_failure;

if (nla_put_u64(skb, L2TP_ATTR_TX_PACKETS, tunnel->stats.tx_packets) ||
nla_put_u64(skb, L2TP_ATTR_TX_BYTES, tunnel->stats.tx_bytes) ||
nla_put_u64(skb, L2TP_ATTR_TX_ERRORS, tunnel->stats.tx_errors) ||
nla_put_u64(skb, L2TP_ATTR_RX_PACKETS, tunnel->stats.rx_packets) ||
nla_put_u64(skb, L2TP_ATTR_RX_BYTES, tunnel->stats.rx_bytes) ||
do {
start = u64_stats_fetch_begin(&tunnel->stats.syncp);
stats.tx_packets = tunnel->stats.tx_packets;
stats.tx_bytes = tunnel->stats.tx_bytes;
stats.tx_errors = tunnel->stats.tx_errors;
stats.rx_packets = tunnel->stats.rx_packets;
stats.rx_bytes = tunnel->stats.rx_bytes;
stats.rx_errors = tunnel->stats.rx_errors;
stats.rx_seq_discards = tunnel->stats.rx_seq_discards;
stats.rx_oos_packets = tunnel->stats.rx_oos_packets;
} while (u64_stats_fetch_retry(&tunnel->stats.syncp, start));

if (nla_put_u64(skb, L2TP_ATTR_TX_PACKETS, stats.tx_packets) ||
nla_put_u64(skb, L2TP_ATTR_TX_BYTES, stats.tx_bytes) ||
nla_put_u64(skb, L2TP_ATTR_TX_ERRORS, stats.tx_errors) ||
nla_put_u64(skb, L2TP_ATTR_RX_PACKETS, stats.rx_packets) ||
nla_put_u64(skb, L2TP_ATTR_RX_BYTES, stats.rx_bytes) ||
nla_put_u64(skb, L2TP_ATTR_RX_SEQ_DISCARDS,
tunnel->stats.rx_seq_discards) ||
stats.rx_seq_discards) ||
nla_put_u64(skb, L2TP_ATTR_RX_OOS_PACKETS,
tunnel->stats.rx_oos_packets) ||
nla_put_u64(skb, L2TP_ATTR_RX_ERRORS, tunnel->stats.rx_errors))
stats.rx_oos_packets) ||
nla_put_u64(skb, L2TP_ATTR_RX_ERRORS, stats.rx_errors))
goto nla_put_failure;
nla_nest_end(skb, nest);

Expand Down Expand Up @@ -563,6 +577,8 @@ static int l2tp_nl_session_send(struct sk_buff *skb, u32 pid, u32 seq, int flags
struct nlattr *nest;
struct l2tp_tunnel *tunnel = session->tunnel;
struct sock *sk = NULL;
struct l2tp_stats stats;
unsigned int start;

sk = tunnel->sock;

Expand Down Expand Up @@ -600,19 +616,33 @@ static int l2tp_nl_session_send(struct sk_buff *skb, u32 pid, u32 seq, int flags
(session->reorder_timeout &&
nla_put_msecs(skb, L2TP_ATTR_RECV_TIMEOUT, session->reorder_timeout)))
goto nla_put_failure;

nest = nla_nest_start(skb, L2TP_ATTR_STATS);
if (nest == NULL)
goto nla_put_failure;
if (nla_put_u64(skb, L2TP_ATTR_TX_PACKETS, session->stats.tx_packets) ||
nla_put_u64(skb, L2TP_ATTR_TX_BYTES, session->stats.tx_bytes) ||
nla_put_u64(skb, L2TP_ATTR_TX_ERRORS, session->stats.tx_errors) ||
nla_put_u64(skb, L2TP_ATTR_RX_PACKETS, session->stats.rx_packets) ||
nla_put_u64(skb, L2TP_ATTR_RX_BYTES, session->stats.rx_bytes) ||

do {
start = u64_stats_fetch_begin(&session->stats.syncp);
stats.tx_packets = session->stats.tx_packets;
stats.tx_bytes = session->stats.tx_bytes;
stats.tx_errors = session->stats.tx_errors;
stats.rx_packets = session->stats.rx_packets;
stats.rx_bytes = session->stats.rx_bytes;
stats.rx_errors = session->stats.rx_errors;
stats.rx_seq_discards = session->stats.rx_seq_discards;
stats.rx_oos_packets = session->stats.rx_oos_packets;
} while (u64_stats_fetch_retry(&session->stats.syncp, start));

if (nla_put_u64(skb, L2TP_ATTR_TX_PACKETS, stats.tx_packets) ||
nla_put_u64(skb, L2TP_ATTR_TX_BYTES, stats.tx_bytes) ||
nla_put_u64(skb, L2TP_ATTR_TX_ERRORS, stats.tx_errors) ||
nla_put_u64(skb, L2TP_ATTR_RX_PACKETS, stats.rx_packets) ||
nla_put_u64(skb, L2TP_ATTR_RX_BYTES, stats.rx_bytes) ||
nla_put_u64(skb, L2TP_ATTR_RX_SEQ_DISCARDS,
session->stats.rx_seq_discards) ||
stats.rx_seq_discards) ||
nla_put_u64(skb, L2TP_ATTR_RX_OOS_PACKETS,
session->stats.rx_oos_packets) ||
nla_put_u64(skb, L2TP_ATTR_RX_ERRORS, session->stats.rx_errors))
stats.rx_oos_packets) ||
nla_put_u64(skb, L2TP_ATTR_RX_ERRORS, stats.rx_errors))
goto nla_put_failure;
nla_nest_end(skb, nest);

Expand Down

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