[PATCH v5 1/2] SQUASH: tcp/dcpp: Convert timewait timer into a delayed_work

[Valentin Schneider <vschneid@redhat.com>]

!NOTE! this changes behaviour, as the tw_timer is TIMER_PINNED and delayed
works currently cannot behave as such. TIMER_PINNED timers are enqueued
onto the local base, whereas delayed_works have their timer enqueued on the
global base AND also check for HK_TYPE_TIMER isolation.

The split between this commit and the next is mainly there for ease of
reviewing. This commit should be squashed with the next one.

Signed-off-by: Valentin Schneider <vschneid@redhat.com>
---
 include/net/inet_timewait_sock.h                 |  2 +-
 net/ipv4/inet_diag.c                             |  2 +-
 net/ipv4/inet_timewait_sock.c                    | 16 +++++++++-------
 net/ipv4/tcp_ipv4.c                              |  2 +-
 net/ipv6/tcp_ipv6.c                              |  2 +-
 .../testing/selftests/bpf/progs/bpf_iter_tcp4.c  |  2 +-
 .../testing/selftests/bpf/progs/bpf_iter_tcp6.c  |  2 +-
 7 files changed, 15 insertions(+), 13 deletions(-)

diff --git a/include/net/inet_timewait_sock.h b/include/net/inet_timewait_sock.h
index f28da08a37b4e..c4d64f1f8d415 100644
--- a/include/net/inet_timewait_sock.h
+++ b/include/net/inet_timewait_sock.h
@@ -72,7 +72,7 @@ struct inet_timewait_sock {
 				tw_tos		: 8;
 	u32			tw_txhash;
 	u32			tw_priority;
-	struct timer_list	tw_timer;
+	struct delayed_work     tw_expiry_work;
 	struct inet_bind_bucket	*tw_tb;
 	struct inet_bind2_bucket	*tw_tb2;
 };
diff --git a/net/ipv4/inet_diag.c b/net/ipv4/inet_diag.c
index 7adace541fe29..ab11b688f1eeb 100644
--- a/net/ipv4/inet_diag.c
+++ b/net/ipv4/inet_diag.c
@@ -444,7 +444,7 @@ static int inet_twsk_diag_fill(struct sock *sk,
 
 	r->idiag_state	      = tw->tw_substate;
 	r->idiag_timer	      = 3;
-	tmo = tw->tw_timer.expires - jiffies;
+	tmo = tw->tw_expiry_work.timer.expires - jiffies;
 	r->idiag_expires      = jiffies_delta_to_msecs(tmo);
 	r->idiag_rqueue	      = 0;
 	r->idiag_wqueue	      = 0;
diff --git a/net/ipv4/inet_timewait_sock.c b/net/ipv4/inet_timewait_sock.c
index e8de45d34d56a..7a2dcbaa1a61e 100644
--- a/net/ipv4/inet_timewait_sock.c
+++ b/net/ipv4/inet_timewait_sock.c
@@ -150,11 +150,13 @@ void inet_twsk_hashdance(struct inet_timewait_sock *tw, struct sock *sk,
 }
 EXPORT_SYMBOL_GPL(inet_twsk_hashdance);
 
-static void tw_timer_handler(struct timer_list *t)
+static void tw_expiry_workfn(struct work_struct *work)
 {
-	struct inet_timewait_sock *tw = from_timer(tw, t, tw_timer);
-
+	struct inet_timewait_sock *tw = container_of(
+		work, struct inet_timewait_sock, tw_expiry_work.work);
+	local_bh_disable();
 	inet_twsk_kill(tw);
+	local_bh_enable();
 }
 
 struct inet_timewait_sock *inet_twsk_alloc(const struct sock *sk,
@@ -192,7 +194,7 @@ struct inet_timewait_sock *inet_twsk_alloc(const struct sock *sk,
 		tw->tw_prot	    = sk->sk_prot_creator;
 		atomic64_set(&tw->tw_cookie, atomic64_read(&sk->sk_cookie));
 		twsk_net_set(tw, sock_net(sk));
-		timer_setup(&tw->tw_timer, tw_timer_handler, TIMER_PINNED);
+		INIT_DELAYED_WORK(&tw->tw_expiry_work, tw_expiry_workfn);
 		/*
 		 * Because we use RCU lookups, we should not set tw_refcnt
 		 * to a non null value before everything is setup for this
@@ -217,7 +219,7 @@ EXPORT_SYMBOL_GPL(inet_twsk_alloc);
  */
 void inet_twsk_deschedule_put(struct inet_timewait_sock *tw)
 {
-	if (del_timer_sync(&tw->tw_timer))
+	if (cancel_delayed_work_sync(&tw->tw_expiry_work))
 		inet_twsk_kill(tw);
 	inet_twsk_put(tw);
 }
@@ -255,10 +257,10 @@ void __inet_twsk_schedule(struct inet_timewait_sock *tw, int timeo, bool rearm)
 
 		__NET_INC_STATS(twsk_net(tw), kill ? LINUX_MIB_TIMEWAITKILLED :
 						     LINUX_MIB_TIMEWAITED);
-		BUG_ON(mod_timer(&tw->tw_timer, jiffies + timeo));
+		BUG_ON(!queue_delayed_work(system_unbound_wq, &tw->tw_expiry_work, timeo));
 		refcount_inc(&tw->tw_dr->tw_refcount);
 	} else {
-		mod_timer_pending(&tw->tw_timer, jiffies + timeo);
+		mod_delayed_work(system_unbound_wq, &tw->tw_expiry_work, timeo);
 	}
 }
 EXPORT_SYMBOL_GPL(__inet_twsk_schedule);
diff --git a/net/ipv4/tcp_ipv4.c b/net/ipv4/tcp_ipv4.c
index a22ee58387518..4b106f017a81f 100644
--- a/net/ipv4/tcp_ipv4.c
+++ b/net/ipv4/tcp_ipv4.c
@@ -2920,7 +2920,7 @@ static void get_tcp4_sock(struct sock *sk, struct seq_file *f, int i)
 static void get_timewait4_sock(const struct inet_timewait_sock *tw,
 			       struct seq_file *f, int i)
 {
-	long delta = tw->tw_timer.expires - jiffies;
+	long delta = tw->tw_expiry_work.timer.expires - jiffies;
 	__be32 dest, src;
 	__u16 destp, srcp;
 
diff --git a/net/ipv6/tcp_ipv6.c b/net/ipv6/tcp_ipv6.c
index 3f4cba49e9ee6..58cd12fdc91a5 100644
--- a/net/ipv6/tcp_ipv6.c
+++ b/net/ipv6/tcp_ipv6.c
@@ -2242,7 +2242,7 @@ static void get_tcp6_sock(struct seq_file *seq, struct sock *sp, int i)
 static void get_timewait6_sock(struct seq_file *seq,
 			       struct inet_timewait_sock *tw, int i)
 {
-	long delta = tw->tw_timer.expires - jiffies;
+	long delta = tw->tw_expiry_work.timer.expires - jiffies;
 	const struct in6_addr *dest, *src;
 	__u16 destp, srcp;
 
diff --git a/tools/testing/selftests/bpf/progs/bpf_iter_tcp4.c b/tools/testing/selftests/bpf/progs/bpf_iter_tcp4.c
index 92267abb462fc..a429f4eb9939c 100644
--- a/tools/testing/selftests/bpf/progs/bpf_iter_tcp4.c
+++ b/tools/testing/selftests/bpf/progs/bpf_iter_tcp4.c
@@ -152,7 +152,7 @@ static int dump_tw_sock(struct seq_file *seq, struct tcp_timewait_sock *ttw,
 	__be32 dest, src;
 	long delta;
 
-	delta = tw->tw_timer.expires - bpf_jiffies64();
+	delta = tw->tw_expiry_work.timer.expires - bpf_jiffies64();
 	dest = tw->tw_daddr;
 	src  = tw->tw_rcv_saddr;
 	destp = bpf_ntohs(tw->tw_dport);
diff --git a/tools/testing/selftests/bpf/progs/bpf_iter_tcp6.c b/tools/testing/selftests/bpf/progs/bpf_iter_tcp6.c
index 943f7bba180e7..795bb34c95f72 100644
--- a/tools/testing/selftests/bpf/progs/bpf_iter_tcp6.c
+++ b/tools/testing/selftests/bpf/progs/bpf_iter_tcp6.c
@@ -157,7 +157,7 @@ static int dump_tw_sock(struct seq_file *seq, struct tcp_timewait_sock *ttw,
 	__u16 destp, srcp;
 	long delta;
 
-	delta = tw->tw_timer.expires - bpf_jiffies64();
+	delta = tw->tw_expiry_work.timer.expires - bpf_jiffies64();
 	dest = &tw->tw_v6_daddr;
 	src  = &tw->tw_v6_rcv_saddr;
 	destp = bpf_ntohs(tw->tw_dport);
-- 
2.43.0