From d507204d3c5cc57d9a8bdf0a477615bb59ea1611 Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Mon, 24 Jan 2022 12:24:52 -0800 Subject: tcp/dccp: add tw->tw_bslot We want to allow inet_twsk_kill() working even if netns has been dismantled/freed, to get rid of inet_twsk_purge(). This patch adds tw->tw_bslot to cache the bind bucket slot so that inet_twsk_kill() no longer needs to dereference twsk_net(tw) Signed-off-by: Eric Dumazet Signed-off-by: David S. Miller --- include/net/inet_timewait_sock.h | 1 + net/ipv4/inet_timewait_sock.c | 11 +++++++---- 2 files changed, 8 insertions(+), 4 deletions(-) diff --git a/include/net/inet_timewait_sock.h b/include/net/inet_timewait_sock.h index dfd919b3119e..c221fe2b77dd 100644 --- a/include/net/inet_timewait_sock.h +++ b/include/net/inet_timewait_sock.h @@ -72,6 +72,7 @@ struct inet_timewait_sock { tw_tos : 8; u32 tw_txhash; u32 tw_priority; + u32 tw_bslot; /* bind bucket slot */ struct timer_list tw_timer; struct inet_bind_bucket *tw_tb; }; diff --git a/net/ipv4/inet_timewait_sock.c b/net/ipv4/inet_timewait_sock.c index 437afe392e66..6e8f4a6cd222 100644 --- a/net/ipv4/inet_timewait_sock.c +++ b/net/ipv4/inet_timewait_sock.c @@ -52,8 +52,7 @@ static void inet_twsk_kill(struct inet_timewait_sock *tw) spin_unlock(lock); /* Disassociate with bind bucket. */ - bhead = &hashinfo->bhash[inet_bhashfn(twsk_net(tw), tw->tw_num, - hashinfo->bhash_size)]; + bhead = &hashinfo->bhash[tw->tw_bslot]; spin_lock(&bhead->lock); inet_twsk_bind_unhash(tw, hashinfo); @@ -110,8 +109,12 @@ void inet_twsk_hashdance(struct inet_timewait_sock *tw, struct sock *sk, Note, that any socket with inet->num != 0 MUST be bound in binding cache, even if it is closed. */ - bhead = &hashinfo->bhash[inet_bhashfn(twsk_net(tw), inet->inet_num, - hashinfo->bhash_size)]; + /* Cache inet_bhashfn(), because 'struct net' might be no longer + * available later in inet_twsk_kill(). + */ + tw->tw_bslot = inet_bhashfn(twsk_net(tw), inet->inet_num, + hashinfo->bhash_size); + bhead = &hashinfo->bhash[tw->tw_bslot]; spin_lock(&bhead->lock); tw->tw_tb = icsk->icsk_bind_hash; WARN_ON(!icsk->icsk_bind_hash); -- cgit v1.2.3