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Date: Sun, 28 Mar 2021 13:20:02 -0700
From: Cong Wang <xiyou.wangcong@...il.com>
To: netdev@...r.kernel.org
Cc: bpf@...r.kernel.org, duanxiongchun@...edance.com,
wangdongdong.6@...edance.com, jiang.wang@...edance.com,
Cong Wang <cong.wang@...edance.com>,
John Fastabend <john.fastabend@...il.com>,
Daniel Borkmann <daniel@...earbox.net>,
Lorenz Bauer <lmb@...udflare.com>,
Jakub Sitnicki <jakub@...udflare.com>
Subject: [Patch bpf-next v7 02/13] skmsg: introduce a spinlock to protect ingress_msg
From: Cong Wang <cong.wang@...edance.com>
Currently we rely on lock_sock to protect ingress_msg,
it is too big for this, we can actually just use a spinlock
to protect this list like protecting other skb queues.
__tcp_bpf_recvmsg() is still special because of peeking,
it still has to use lock_sock.
Cc: John Fastabend <john.fastabend@...il.com>
Cc: Daniel Borkmann <daniel@...earbox.net>
Cc: Lorenz Bauer <lmb@...udflare.com>
Acked-by: Jakub Sitnicki <jakub@...udflare.com>
Signed-off-by: Cong Wang <cong.wang@...edance.com>
---
include/linux/skmsg.h | 46 +++++++++++++++++++++++++++++++++++++++++++
net/core/skmsg.c | 3 +++
net/ipv4/tcp_bpf.c | 18 ++++++-----------
3 files changed, 55 insertions(+), 12 deletions(-)
diff --git a/include/linux/skmsg.h b/include/linux/skmsg.h
index 6c09d94be2e9..f2d45a73b2b2 100644
--- a/include/linux/skmsg.h
+++ b/include/linux/skmsg.h
@@ -89,6 +89,7 @@ struct sk_psock {
#endif
struct sk_buff_head ingress_skb;
struct list_head ingress_msg;
+ spinlock_t ingress_lock;
unsigned long state;
struct list_head link;
spinlock_t link_lock;
@@ -284,7 +285,45 @@ static inline struct sk_psock *sk_psock(const struct sock *sk)
static inline void sk_psock_queue_msg(struct sk_psock *psock,
struct sk_msg *msg)
{
+ spin_lock_bh(&psock->ingress_lock);
list_add_tail(&msg->list, &psock->ingress_msg);
+ spin_unlock_bh(&psock->ingress_lock);
+}
+
+static inline struct sk_msg *sk_psock_dequeue_msg(struct sk_psock *psock)
+{
+ struct sk_msg *msg;
+
+ spin_lock_bh(&psock->ingress_lock);
+ msg = list_first_entry_or_null(&psock->ingress_msg, struct sk_msg, list);
+ if (msg)
+ list_del(&msg->list);
+ spin_unlock_bh(&psock->ingress_lock);
+ return msg;
+}
+
+static inline struct sk_msg *sk_psock_peek_msg(struct sk_psock *psock)
+{
+ struct sk_msg *msg;
+
+ spin_lock_bh(&psock->ingress_lock);
+ msg = list_first_entry_or_null(&psock->ingress_msg, struct sk_msg, list);
+ spin_unlock_bh(&psock->ingress_lock);
+ return msg;
+}
+
+static inline struct sk_msg *sk_psock_next_msg(struct sk_psock *psock,
+ struct sk_msg *msg)
+{
+ struct sk_msg *ret;
+
+ spin_lock_bh(&psock->ingress_lock);
+ if (list_is_last(&msg->list, &psock->ingress_msg))
+ ret = NULL;
+ else
+ ret = list_next_entry(msg, list);
+ spin_unlock_bh(&psock->ingress_lock);
+ return ret;
}
static inline bool sk_psock_queue_empty(const struct sk_psock *psock)
@@ -292,6 +331,13 @@ static inline bool sk_psock_queue_empty(const struct sk_psock *psock)
return psock ? list_empty(&psock->ingress_msg) : true;
}
+static inline void kfree_sk_msg(struct sk_msg *msg)
+{
+ if (msg->skb)
+ consume_skb(msg->skb);
+ kfree(msg);
+}
+
static inline void sk_psock_report_error(struct sk_psock *psock, int err)
{
struct sock *sk = psock->sk;
diff --git a/net/core/skmsg.c b/net/core/skmsg.c
index bebf84ed4e30..305dddc51857 100644
--- a/net/core/skmsg.c
+++ b/net/core/skmsg.c
@@ -592,6 +592,7 @@ struct sk_psock *sk_psock_init(struct sock *sk, int node)
INIT_WORK(&psock->work, sk_psock_backlog);
INIT_LIST_HEAD(&psock->ingress_msg);
+ spin_lock_init(&psock->ingress_lock);
skb_queue_head_init(&psock->ingress_skb);
sk_psock_set_state(psock, SK_PSOCK_TX_ENABLED);
@@ -638,7 +639,9 @@ static void sk_psock_zap_ingress(struct sk_psock *psock)
skb_bpf_redirect_clear(skb);
kfree_skb(skb);
}
+ spin_lock_bh(&psock->ingress_lock);
__sk_psock_purge_ingress_msg(psock);
+ spin_unlock_bh(&psock->ingress_lock);
}
static void sk_psock_link_destroy(struct sk_psock *psock)
diff --git a/net/ipv4/tcp_bpf.c b/net/ipv4/tcp_bpf.c
index 17c322b875fd..ae980716d896 100644
--- a/net/ipv4/tcp_bpf.c
+++ b/net/ipv4/tcp_bpf.c
@@ -18,9 +18,7 @@ int __tcp_bpf_recvmsg(struct sock *sk, struct sk_psock *psock,
struct sk_msg *msg_rx;
int i, copied = 0;
- msg_rx = list_first_entry_or_null(&psock->ingress_msg,
- struct sk_msg, list);
-
+ msg_rx = sk_psock_peek_msg(psock);
while (copied != len) {
struct scatterlist *sge;
@@ -68,22 +66,18 @@ int __tcp_bpf_recvmsg(struct sock *sk, struct sk_psock *psock,
} while (i != msg_rx->sg.end);
if (unlikely(peek)) {
- if (msg_rx == list_last_entry(&psock->ingress_msg,
- struct sk_msg, list))
+ msg_rx = sk_psock_next_msg(psock, msg_rx);
+ if (!msg_rx)
break;
- msg_rx = list_next_entry(msg_rx, list);
continue;
}
msg_rx->sg.start = i;
if (!sge->length && msg_rx->sg.start == msg_rx->sg.end) {
- list_del(&msg_rx->list);
- if (msg_rx->skb)
- consume_skb(msg_rx->skb);
- kfree(msg_rx);
+ msg_rx = sk_psock_dequeue_msg(psock);
+ kfree_sk_msg(msg_rx);
}
- msg_rx = list_first_entry_or_null(&psock->ingress_msg,
- struct sk_msg, list);
+ msg_rx = sk_psock_peek_msg(psock);
}
return copied;
--
2.25.1
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