[PATCH 6.12 010/114] tcp_bpf: Charge receive socket buffer in bpf_tcp_ingress()

[Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>]

6.12-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Cong Wang <cong.wang@xxxxxxxxxxxxx>

[ Upstream commit 54f89b3178d5448dd4457afbb98fc1ab99090a65 ]

When bpf_tcp_ingress() is called, the skmsg is being redirected to the
ingress of the destination socket. Therefore, we should charge its
receive socket buffer, instead of sending socket buffer.

Because sk_rmem_schedule() tests pfmemalloc of skb, we need to
introduce a wrapper and call it for skmsg.

Fixes: 604326b41a6f ("bpf, sockmap: convert to generic sk_msg interface")
Signed-off-by: Cong Wang <cong.wang@xxxxxxxxxxxxx>
Signed-off-by: Daniel Borkmann <daniel@xxxxxxxxxxxxx>
Reviewed-by: John Fastabend <john.fastabend@xxxxxxxxx>
Link: https://lore.kernel.org/bpf/20241210012039.1669389-2-zijianzhang@xxxxxxxxxxxxx
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 include/net/sock.h | 10 ++++++++--
 net/ipv4/tcp_bpf.c |  2 +-
 2 files changed, 9 insertions(+), 3 deletions(-)

diff --git a/include/net/sock.h b/include/net/sock.h
index f29c14448938..fa055cf1785e 100644
--- a/include/net/sock.h
+++ b/include/net/sock.h
@@ -1521,7 +1521,7 @@ static inline bool sk_wmem_schedule(struct sock *sk, int size)
 }
 
 static inline bool
-sk_rmem_schedule(struct sock *sk, struct sk_buff *skb, int size)
+__sk_rmem_schedule(struct sock *sk, int size, bool pfmemalloc)
 {
 	int delta;
 
@@ -1529,7 +1529,13 @@ sk_rmem_schedule(struct sock *sk, struct sk_buff *skb, int size)
 		return true;
 	delta = size - sk->sk_forward_alloc;
 	return delta <= 0 || __sk_mem_schedule(sk, delta, SK_MEM_RECV) ||
-		skb_pfmemalloc(skb);
+	       pfmemalloc;
+}
+
+static inline bool
+sk_rmem_schedule(struct sock *sk, struct sk_buff *skb, int size)
+{
+	return __sk_rmem_schedule(sk, size, skb_pfmemalloc(skb));
 }
 
 static inline int sk_unused_reserved_mem(const struct sock *sk)
diff --git a/net/ipv4/tcp_bpf.c b/net/ipv4/tcp_bpf.c
index 99cef92e6290..b21ea634909c 100644
--- a/net/ipv4/tcp_bpf.c
+++ b/net/ipv4/tcp_bpf.c
@@ -49,7 +49,7 @@ static int bpf_tcp_ingress(struct sock *sk, struct sk_psock *psock,
 		sge = sk_msg_elem(msg, i);
 		size = (apply && apply_bytes < sge->length) ?
 			apply_bytes : sge->length;
-		if (!sk_wmem_schedule(sk, size)) {
+		if (!__sk_rmem_schedule(sk, size, false)) {
 			if (!copied)
 				ret = -ENOMEM;
 			break;
-- 
2.39.5