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 | |
| 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')
| -rw-r--r-- | net/ipv4/tcp.c | 18 | ||||
| -rw-r--r-- | net/ipv4/tcp_fastopen.c | 2 | ||||
| -rw-r--r-- | net/ipv4/tcp_input.c | 6 |
3 files changed, 6 insertions, 20 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); diff --git a/net/ipv4/tcp_fastopen.c b/net/ipv4/tcp_fastopen.c index ca40665145c6..1a6b1bc54245 100644 --- a/net/ipv4/tcp_fastopen.c +++ b/net/ipv4/tcp_fastopen.c @@ -189,7 +189,7 @@ void tcp_fastopen_add_skb(struct sock *sk, struct sk_buff *skb) tcp_segs_in(tp, skb); __skb_pull(skb, tcp_hdrlen(skb)); sk_forced_mem_schedule(sk, skb->truesize); - tcp_skb_set_owner_r(skb, sk); + skb_set_owner_r(skb, sk); TCP_SKB_CB(skb)->seq++; TCP_SKB_CB(skb)->tcp_flags &= ~TCPHDR_SYN; diff --git a/net/ipv4/tcp_input.c b/net/ipv4/tcp_input.c index e1f952fbac48..a35018e2d0ba 100644 --- a/net/ipv4/tcp_input.c +++ b/net/ipv4/tcp_input.c @@ -5171,7 +5171,7 @@ end: if (tcp_is_sack(tp)) tcp_grow_window(sk, skb, false); skb_condense(skb); - tcp_skb_set_owner_r(skb, sk); + skb_set_owner_r(skb, sk); } } @@ -5187,7 +5187,7 @@ static int __must_check tcp_queue_rcv(struct sock *sk, struct sk_buff *skb, tcp_rcv_nxt_update(tcp_sk(sk), TCP_SKB_CB(skb)->end_seq); if (!eaten) { tcp_add_receive_queue(sk, skb); - tcp_skb_set_owner_r(skb, sk); + skb_set_owner_r(skb, sk); } return eaten; } @@ -5504,7 +5504,7 @@ skip_this: __skb_queue_before(list, skb, nskb); else __skb_queue_tail(&tmp, nskb); /* defer rbtree insertion */ - tcp_skb_set_owner_r(nskb, sk); + skb_set_owner_r(nskb, sk); mptcp_skb_ext_move(nskb, skb); /* Copy data, releasing collapsed skbs. */ |