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Message-Id: <1334912573-28804-2-git-send-email-jchapman@katalix.com>
Date: Fri, 20 Apr 2012 10:02:44 +0100
From: James Chapman <jchapman@...alix.com>
To: netdev@...r.kernel.org
Cc: bcrl@...ck.org
Subject: [PATCH 01/10] l2tp: fix locking of 64-bit counters for smp
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 <jchapman@...alix.com>
---
net/l2tp/l2tp_core.c | 75 +++++++++++++++++++++++++++++++++++------------
net/l2tp/l2tp_core.h | 1 +
net/l2tp/l2tp_netlink.c | 62 ++++++++++++++++++++++++++++----------
3 files changed, 103 insertions(+), 35 deletions(-)
diff --git a/net/l2tp/l2tp_core.c b/net/l2tp/l2tp_core.c
index 8cd5f4b..5e27c05 100644
--- a/net/l2tp/l2tp_core.c
+++ b/net/l2tp/l2tp_core.c
@@ -329,8 +329,10 @@ 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);
@@ -338,7 +340,9 @@ static void l2tp_recv_queue_skb(struct l2tp_session *session, struct sk_buff *sk
"%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;
}
}
@@ -355,16 +359,23 @@ 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 */
@@ -395,6 +406,7 @@ 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
@@ -402,10 +414,13 @@ static void l2tp_recv_dequeue(struct l2tp_session *session)
*/
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",
@@ -557,6 +572,7 @@ 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
@@ -572,7 +588,9 @@ 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;
@@ -641,7 +659,9 @@ 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;
}
@@ -660,7 +680,9 @@ 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;
}
}
@@ -714,7 +736,9 @@ 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",
@@ -741,7 +765,9 @@ 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)
@@ -767,6 +793,7 @@ 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;
@@ -859,7 +886,10 @@ 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;
@@ -985,6 +1015,7 @@ 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)
@@ -1021,15 +1052,21 @@ 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;
}
diff --git a/net/l2tp/l2tp_core.h b/net/l2tp/l2tp_core.h
index 09e4a38..a8c943b 100644
--- a/net/l2tp/l2tp_core.h
+++ b/net/l2tp/l2tp_core.h
@@ -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;
diff --git a/net/l2tp/l2tp_netlink.c b/net/l2tp/l2tp_netlink.c
index bc8c334..1dbb977 100644
--- a/net/l2tp/l2tp_netlink.c
+++ b/net/l2tp/l2tp_netlink.c
@@ -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);
@@ -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);
@@ -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;
@@ -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);
--
1.7.0.4
--
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