mirror of
https://github.com/bolucat/Archive.git
synced 2026-04-23 00:17:16 +08:00
github-action[bot]
125 lines
3.8 KiB
Diff
125 lines
3.8 KiB
Diff
From 4f54dff818d7b5b1d84becd5d90bc46e6233c0d7 Mon Sep 17 00:00:00 2001
|
|
From: Qingfang Deng <dqfext@gmail.com>
|
|
Date: Thu, 28 Aug 2025 09:20:17 +0800
|
|
Subject: [PATCH] pppoe: drop sock reference counting on fast path
|
|
|
|
Now that PPPoE sockets are freed via RCU (SOCK_RCU_FREE), it is no longer
|
|
necessary to take a reference count when looking up sockets on the receive
|
|
path. Readers are protected by RCU, so the socket memory remains valid
|
|
until after a grace period.
|
|
|
|
Convert fast-path lookups to avoid refcounting:
|
|
- Replace get_item() and sk_receive_skb() in pppoe_rcv() with
|
|
__get_item() and __sk_receive_skb().
|
|
- Rework get_item_by_addr() into __get_item_by_addr() (no refcount and
|
|
move RCU lock into pppoe_ioctl)
|
|
- Remove unnecessary sock_put() calls.
|
|
|
|
This avoids cacheline bouncing from atomic reference counting and improves
|
|
performance on the receive fast path.
|
|
|
|
Signed-off-by: Qingfang Deng <dqfext@gmail.com>
|
|
Reviewed-by: Eric Dumazet <edumazet@google.com>
|
|
Link: https://patch.msgid.link/20250828012018.15922-2-dqfext@gmail.com
|
|
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
|
|
---
|
|
drivers/net/ppp/pppoe.c | 35 +++++++++++++----------------------
|
|
1 file changed, 13 insertions(+), 22 deletions(-)
|
|
|
|
--- a/drivers/net/ppp/pppoe.c
|
|
+++ b/drivers/net/ppp/pppoe.c
|
|
@@ -237,8 +237,8 @@ static inline struct pppox_sock *get_ite
|
|
return po;
|
|
}
|
|
|
|
-static inline struct pppox_sock *get_item_by_addr(struct net *net,
|
|
- struct sockaddr_pppox *sp)
|
|
+static inline struct pppox_sock *__get_item_by_addr(struct net *net,
|
|
+ struct sockaddr_pppox *sp)
|
|
{
|
|
struct net_device *dev;
|
|
struct pppoe_net *pn;
|
|
@@ -246,15 +246,13 @@ static inline struct pppox_sock *get_ite
|
|
|
|
int ifindex;
|
|
|
|
- rcu_read_lock();
|
|
dev = dev_get_by_name_rcu(net, sp->sa_addr.pppoe.dev);
|
|
if (dev) {
|
|
ifindex = dev->ifindex;
|
|
pn = pppoe_pernet(net);
|
|
- pppox_sock = get_item(pn, sp->sa_addr.pppoe.sid,
|
|
- sp->sa_addr.pppoe.remote, ifindex);
|
|
+ pppox_sock = __get_item(pn, sp->sa_addr.pppoe.sid,
|
|
+ sp->sa_addr.pppoe.remote, ifindex);
|
|
}
|
|
- rcu_read_unlock();
|
|
return pppox_sock;
|
|
}
|
|
|
|
@@ -384,18 +382,16 @@ static int pppoe_rcv_core(struct sock *s
|
|
if (sk->sk_state & PPPOX_BOUND) {
|
|
ppp_input(&po->chan, skb);
|
|
} else if (sk->sk_state & PPPOX_RELAY) {
|
|
- relay_po = get_item_by_addr(sock_net(sk),
|
|
- &po->pppoe_relay);
|
|
+ relay_po = __get_item_by_addr(sock_net(sk),
|
|
+ &po->pppoe_relay);
|
|
if (relay_po == NULL)
|
|
goto abort_kfree;
|
|
|
|
if ((sk_pppox(relay_po)->sk_state & PPPOX_CONNECTED) == 0)
|
|
- goto abort_put;
|
|
+ goto abort_kfree;
|
|
|
|
if (!__pppoe_xmit(sk_pppox(relay_po), skb))
|
|
- goto abort_put;
|
|
-
|
|
- sock_put(sk_pppox(relay_po));
|
|
+ goto abort_kfree;
|
|
} else {
|
|
if (sock_queue_rcv_skb(sk, skb))
|
|
goto abort_kfree;
|
|
@@ -403,9 +399,6 @@ static int pppoe_rcv_core(struct sock *s
|
|
|
|
return NET_RX_SUCCESS;
|
|
|
|
-abort_put:
|
|
- sock_put(sk_pppox(relay_po));
|
|
-
|
|
abort_kfree:
|
|
kfree_skb(skb);
|
|
return NET_RX_DROP;
|
|
@@ -447,14 +440,11 @@ static int pppoe_rcv(struct sk_buff *skb
|
|
ph = pppoe_hdr(skb);
|
|
pn = pppoe_pernet(dev_net(dev));
|
|
|
|
- /* Note that get_item does a sock_hold(), so sk_pppox(po)
|
|
- * is known to be safe.
|
|
- */
|
|
- po = get_item(pn, ph->sid, eth_hdr(skb)->h_source, dev->ifindex);
|
|
+ po = __get_item(pn, ph->sid, eth_hdr(skb)->h_source, dev->ifindex);
|
|
if (!po)
|
|
goto drop;
|
|
|
|
- return sk_receive_skb(sk_pppox(po), skb, 0);
|
|
+ return __sk_receive_skb(sk_pppox(po), skb, 0, 1, false);
|
|
|
|
drop:
|
|
kfree_skb(skb);
|
|
@@ -820,11 +810,12 @@ static int pppoe_ioctl(struct socket *so
|
|
|
|
/* Check that the socket referenced by the address
|
|
actually exists. */
|
|
- relay_po = get_item_by_addr(sock_net(sk), &po->pppoe_relay);
|
|
+ rcu_read_lock();
|
|
+ relay_po = __get_item_by_addr(sock_net(sk), &po->pppoe_relay);
|
|
+ rcu_read_unlock();
|
|
if (!relay_po)
|
|
break;
|
|
|
|
- sock_put(sk_pppox(relay_po));
|
|
sk->sk_state |= PPPOX_RELAY;
|
|
err = 0;
|
|
break;
|