From f278b6d5bb465c7fd66f3d103812947e55b376ed Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Mon, 31 Mar 2025 07:59:46 +0000 Subject: 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 Link: https://patch.msgid.link/20250331075946.31960-1-edumazet@google.com Signed-off-by: Jakub Kicinski --- include/net/tcp.h | 15 --------------- 1 file changed, 15 deletions(-) (limited to 'include') diff --git a/include/net/tcp.h b/include/net/tcp.h index df04dc09c519..4450c384ef17 100644 --- a/include/net/tcp.h +++ b/include/net/tcp.h @@ -779,7 +779,6 @@ static inline int tcp_bound_to_half_wnd(struct tcp_sock *tp, int pktsize) /* tcp.c */ void tcp_get_info(struct sock *, struct tcp_info *); -void tcp_sock_rfree(struct sk_buff *skb); /* Read 'sendfile()'-style from a TCP socket */ int tcp_read_sock(struct sock *sk, read_descriptor_t *desc, @@ -2899,18 +2898,4 @@ enum skb_drop_reason tcp_inbound_hash(struct sock *sk, const void *saddr, const void *daddr, int family, int dif, int sdif); -/* version of skb_set_owner_r() avoiding one atomic_add() */ -static inline void tcp_skb_set_owner_r(struct sk_buff *skb, struct sock *sk) -{ - skb_orphan(skb); - skb->sk = sk; - skb->destructor = tcp_sock_rfree; - - sock_owned_by_me(sk); - atomic_set(&sk->sk_rmem_alloc, - atomic_read(&sk->sk_rmem_alloc) + skb->truesize); - - sk_forward_alloc_add(sk, -skb->truesize); -} - #endif /* _TCP_H */ -- cgit v1.2.3