diff options
| author | Eric Dumazet <edumazet@google.com> | 2025-03-31 07:59:46 +0000 |
|---|---|---|
| committer | Jakub Kicinski <kuba@kernel.org> | 2025-03-31 16:53:54 -0700 |
| commit | f278b6d5bb465c7fd66f3d103812947e55b376ed (patch) | |
| tree | 80f0f7103f809d9a485053e203a62e15e09b4c40 /net/ipv4/tcp.c | |
| parent | dd07df9ff3d148aee87fcbab99ff14f0727752f4 (diff) | |
Revert "tcp: avoid atomic operations on sk->sk_rmem_alloc"
This reverts commit 0de2a5c4b824da2205658ebebb99a55c43cdf60f.
I forgot that a TCP socket could receive messages in its error queue.
sock_queue_err_skb() can be called without socket lock being held,
and changes sk->sk_rmem_alloc.
The fact that skbs in error queue are limited by sk->sk_rcvbuf
means that error messages can be dropped if socket receive
queues are full, which is an orthogonal issue.
In future kernels, we could use a separate sk->sk_error_mem_alloc
counter specifically for the error queue.
Fixes: 0de2a5c4b824 ("tcp: avoid atomic operations on sk->sk_rmem_alloc")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Link: https://patch.msgid.link/20250331075946.31960-1-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Diffstat (limited to 'net/ipv4/tcp.c')
| -rw-r--r-- | net/ipv4/tcp.c | 18 |
1 files changed, 2 insertions, 16 deletions
diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c index ea8de00f669d..6edc441b3702 100644 --- a/net/ipv4/tcp.c +++ b/net/ipv4/tcp.c @@ -1525,25 +1525,11 @@ void tcp_cleanup_rbuf(struct sock *sk, int copied) __tcp_cleanup_rbuf(sk, copied); } -/* private version of sock_rfree() avoiding one atomic_sub() */ -void tcp_sock_rfree(struct sk_buff *skb) -{ - struct sock *sk = skb->sk; - unsigned int len = skb->truesize; - - sock_owned_by_me(sk); - atomic_set(&sk->sk_rmem_alloc, - atomic_read(&sk->sk_rmem_alloc) - len); - - sk_forward_alloc_add(sk, len); - sk_mem_reclaim(sk); -} - static void tcp_eat_recv_skb(struct sock *sk, struct sk_buff *skb) { __skb_unlink(skb, &sk->sk_receive_queue); - if (likely(skb->destructor == tcp_sock_rfree)) { - tcp_sock_rfree(skb); + if (likely(skb->destructor == sock_rfree)) { + sock_rfree(skb); skb->destructor = NULL; skb->sk = NULL; return skb_attempt_defer_free(skb); |