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Now that all of the tcp_input() and all its branches are executed

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in the network epoch, we can greatly simplify synchronization.
Remove all unneccesary epoch enters hidden under INP_INFO_RLOCK macro.
Remove some unneccesary assertions and convert necessary ones into the
NET_EPOCH_ASSERT macro.
This commit is contained in:
Gleb Smirnoff 2019-11-07 21:23:07 +00:00
parent bff7f83d39
commit d40c0d47cd
4 changed files with 11 additions and 136 deletions
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109
sys/netinet/tcp_input.c
View File

@ -561,7 +561,6 @@ tcp_input(struct mbuf **mp, int *offp, int proto)
int rstreason = 0; /* For badport_bandlim accounting purposes */
uint8_t iptos;
struct m_tag *fwd_tag = NULL;
struct epoch_tracker et;
#ifdef INET6
struct ip6_hdr *ip6 = NULL;
int isipv6;
@ -570,7 +569,6 @@ tcp_input(struct mbuf **mp, int *offp, int proto)
#endif /* INET6 */
struct tcpopt to; /* options in this segment */
char *s = NULL; /* address and port logging */
int ti_locked;
#ifdef TCPDEBUG
/*
* The size of tcp_saveipgen must be the size of the max ip header,
@ -581,6 +579,8 @@ tcp_input(struct mbuf **mp, int *offp, int proto)
short ostate = 0;
#endif
NET_EPOCH_ASSERT();
#ifdef INET6
isipv6 = (mtod(m, struct ip *)->ip_v == 6) ? 1 : 0;
#endif
@ -746,19 +746,6 @@ tcp_input(struct mbuf **mp, int *offp, int proto)
*/
drop_hdrlen = off0 + off;
/*
* Locate pcb for segment; if we're likely to add or remove a
* connection then first acquire pcbinfo lock. There are three cases
* where we might discover later we need a write lock despite the
* flags: ACKs moving a connection out of the syncache, ACKs for a
* connection in TIMEWAIT and SYNs not targeting a listening socket.
*/
if ((thflags & (TH_FIN | TH_RST)) != 0) {
INP_INFO_RLOCK_ET(&V_tcbinfo, et);
ti_locked = TI_RLOCKED;
} else
ti_locked = TI_UNLOCKED;
/*
* Grab info from PACKET_TAG_IPFORWARD tag prepended to the chain.
*/
@ -776,13 +763,6 @@ tcp_input(struct mbuf **mp, int *offp, int proto)
fwd_tag = m_tag_find(m, PACKET_TAG_IPFORWARD, NULL);
findpcb:
#ifdef INVARIANTS
if (ti_locked == TI_RLOCKED) {
INP_INFO_RLOCK_ASSERT(&V_tcbinfo);
} else {
INP_INFO_WUNLOCK_ASSERT(&V_tcbinfo);
}
#endif
#ifdef INET6
if (isipv6 && fwd_tag != NULL) {
struct sockaddr_in6 *next_hop6;
@ -942,12 +922,6 @@ tcp_input(struct mbuf **mp, int *offp, int proto)
* XXXRW: It may be time to rethink timewait locking.
*/
if (inp->inp_flags & INP_TIMEWAIT) {
if (ti_locked == TI_UNLOCKED) {
INP_INFO_RLOCK_ET(&V_tcbinfo, et);
ti_locked = TI_RLOCKED;
}
INP_INFO_RLOCK_ASSERT(&V_tcbinfo);
if (thflags & TH_SYN)
tcp_dooptions(&to, optp, optlen, TO_SYN);
/*
@ -955,7 +929,6 @@ tcp_input(struct mbuf **mp, int *offp, int proto)
*/
if (tcp_twcheck(inp, &to, th, m, tlen))
goto findpcb;
INP_INFO_RUNLOCK_ET(&V_tcbinfo, et);
return (IPPROTO_DONE);
}
/*
@ -977,27 +950,6 @@ tcp_input(struct mbuf **mp, int *offp, int proto)
}
#endif
/*
* We've identified a valid inpcb, but it could be that we need an
* inpcbinfo write lock but don't hold it. In this case, attempt to
* acquire using the same strategy as the TIMEWAIT case above. If we
* relock, we have to jump back to 'relocked' as the connection might
* now be in TIMEWAIT.
*/
#ifdef INVARIANTS
if ((thflags & (TH_FIN | TH_RST)) != 0)
INP_INFO_RLOCK_ASSERT(&V_tcbinfo);
#endif
if (!((tp->t_state == TCPS_ESTABLISHED && (thflags & TH_SYN) == 0) ||
(tp->t_state == TCPS_LISTEN && (thflags & TH_SYN) &&
!IS_FASTOPEN(tp->t_flags)))) {
if (ti_locked == TI_UNLOCKED) {
INP_INFO_RLOCK_ET(&V_tcbinfo, et);
ti_locked = TI_RLOCKED;
}
INP_INFO_RLOCK_ASSERT(&V_tcbinfo);
}
#ifdef MAC
INP_WLOCK_ASSERT(inp);
if (mac_inpcb_check_deliver(inp, m))
@ -1052,7 +1004,6 @@ tcp_input(struct mbuf **mp, int *offp, int proto)
*/
if ((thflags & (TH_RST|TH_ACK|TH_SYN)) == TH_ACK) {
INP_INFO_RLOCK_ASSERT(&V_tcbinfo);
/*
* Parse the TCP options here because
* syncookies need access to the reflected
@ -1130,8 +1081,6 @@ tcp_input(struct mbuf **mp, int *offp, int proto)
TCP_PROBE5(receive, NULL, tp, m, tp, th);
tp->t_fb->tfb_tcp_do_segment(m, th, so, tp, drop_hdrlen, tlen,
iptos);
if (ti_locked == TI_RLOCKED)
INP_INFO_RUNLOCK_ET(&V_tcbinfo, et);
return (IPPROTO_DONE);
}
/*
@ -1334,10 +1283,6 @@ tcp_input(struct mbuf **mp, int *offp, int proto)
* Entry added to syncache and mbuf consumed.
* Only the listen socket is unlocked by syncache_add().
*/
if (ti_locked == TI_RLOCKED) {
INP_INFO_RUNLOCK_ET(&V_tcbinfo, et);
ti_locked = TI_UNLOCKED;
}
INP_INFO_WUNLOCK_ASSERT(&V_tcbinfo);
return (IPPROTO_DONE);
} else if (tp->t_state == TCPS_LISTEN) {
@ -1370,25 +1315,11 @@ tcp_input(struct mbuf **mp, int *offp, int proto)
* the inpcb, and unlocks pcbinfo.
*/
tp->t_fb->tfb_tcp_do_segment(m, th, so, tp, drop_hdrlen, tlen, iptos);
if (ti_locked == TI_RLOCKED)
INP_INFO_RUNLOCK_ET(&V_tcbinfo, et);
return (IPPROTO_DONE);
dropwithreset:
TCP_PROBE5(receive, NULL, tp, m, tp, th);
if (ti_locked == TI_RLOCKED) {
INP_INFO_RUNLOCK_ET(&V_tcbinfo, et);
ti_locked = TI_UNLOCKED;
}
#ifdef INVARIANTS
else {
KASSERT(ti_locked == TI_UNLOCKED, ("%s: dropwithreset "
"ti_locked: %d", __func__, ti_locked));
INP_INFO_WUNLOCK_ASSERT(&V_tcbinfo);
}
#endif
if (inp != NULL) {
tcp_dropwithreset(m, th, tp, tlen, rstreason);
INP_WUNLOCK(inp);
@ -1401,18 +1332,6 @@ tcp_input(struct mbuf **mp, int *offp, int proto)
if (m != NULL)
TCP_PROBE5(receive, NULL, tp, m, tp, th);
if (ti_locked == TI_RLOCKED) {
INP_INFO_RUNLOCK_ET(&V_tcbinfo, et);
ti_locked = TI_UNLOCKED;
}
#ifdef INVARIANTS
else {
KASSERT(ti_locked == TI_UNLOCKED, ("%s: dropunlock "
"ti_locked: %d", __func__, ti_locked));
INP_INFO_WUNLOCK_ASSERT(&V_tcbinfo);
}
#endif
if (inp != NULL)
INP_WUNLOCK(inp);
@ -1501,7 +1420,7 @@ tcp_do_segment(struct mbuf *m, struct tcphdr *th, struct socket *so,
struct mbuf *mfree;
struct tcpopt to;
int tfo_syn;
#ifdef TCPDEBUG
/*
* The size of tcp_saveipgen must be the size of the max ip header,
@ -1516,16 +1435,8 @@ tcp_do_segment(struct mbuf *m, struct tcphdr *th, struct socket *so,
tp->sackhint.last_sack_ack = 0;
sack_changed = 0;
nsegs = max(1, m->m_pkthdr.lro_nsegs);
/*
* If this is either a state-changing packet or current state isn't
* established, we require a write lock on tcbinfo. Otherwise, we
* allow the tcbinfo to be in either alocked or unlocked, as the
* caller may have unnecessarily acquired a write lock due to a race.
*/
if ((thflags & (TH_SYN | TH_FIN | TH_RST)) != 0 ||
tp->t_state != TCPS_ESTABLISHED) {
INP_INFO_RLOCK_ASSERT(&V_tcbinfo);
}
NET_EPOCH_ASSERT();
INP_WLOCK_ASSERT(tp->t_inpcb);
KASSERT(tp->t_state > TCPS_LISTEN, ("%s: TCPS_LISTEN",
__func__));
@ -2047,7 +1958,6 @@ tcp_do_segment(struct mbuf *m, struct tcphdr *th, struct socket *so,
tcp_state_change(tp, TCPS_SYN_RECEIVED);
}
INP_INFO_RLOCK_ASSERT(&V_tcbinfo);
INP_WLOCK_ASSERT(tp->t_inpcb);
/*
@ -2120,7 +2030,6 @@ tcp_do_segment(struct mbuf *m, struct tcphdr *th, struct socket *so,
SEQ_LT(th->th_seq, tp->last_ack_sent + tp->rcv_wnd)) ||
(tp->rcv_wnd == 0 && tp->last_ack_sent == th->th_seq)) {
INP_INFO_RLOCK_ASSERT(&V_tcbinfo);
KASSERT(tp->t_state != TCPS_SYN_SENT,
("%s: TH_RST for TCPS_SYN_SENT th %p tp %p",
__func__, th, tp));
@ -2163,8 +2072,6 @@ tcp_do_segment(struct mbuf *m, struct tcphdr *th, struct socket *so,
*/
if ((thflags & TH_SYN) && tp->t_state != TCPS_SYN_SENT &&
tp->t_state != TCPS_SYN_RECEIVED) {
INP_INFO_RLOCK_ASSERT(&V_tcbinfo);
TCPSTAT_INC(tcps_badsyn);
if (V_tcp_insecure_syn &&
SEQ_GEQ(th->th_seq, tp->last_ack_sent) &&
@ -2288,8 +2195,6 @@ tcp_do_segment(struct mbuf *m, struct tcphdr *th, struct socket *so,
*/
if ((so->so_state & SS_NOFDREF) &&
tp->t_state > TCPS_CLOSE_WAIT && tlen) {
INP_INFO_RLOCK_ASSERT(&V_tcbinfo);
if ((s = tcp_log_addrs(inc, th, NULL, NULL))) {
log(LOG_DEBUG, "%s; %s: %s: Received %d bytes of data "
"after socket was closed, "
@ -2875,7 +2780,6 @@ tcp_do_segment(struct mbuf *m, struct tcphdr *th, struct socket *so,
*/
case TCPS_CLOSING:
if (ourfinisacked) {
INP_INFO_RLOCK_ASSERT(&V_tcbinfo);
tcp_twstart(tp);
m_freem(m);
return;
@ -2890,7 +2794,6 @@ tcp_do_segment(struct mbuf *m, struct tcphdr *th, struct socket *so,
*/
case TCPS_LAST_ACK:
if (ourfinisacked) {
INP_INFO_RLOCK_ASSERT(&V_tcbinfo);
tp = tcp_close(tp);
goto drop;
}
@ -3139,8 +3042,6 @@ tcp_do_segment(struct mbuf *m, struct tcphdr *th, struct socket *so,
* standard timers.
*/
case TCPS_FIN_WAIT_2:
INP_INFO_RLOCK_ASSERT(&V_tcbinfo);
tcp_twstart(tp);
return;
}

4
sys/netinet/tcp_stacks/bbr.c
View File

@ -8618,7 +8618,6 @@ bbr_process_data(struct mbuf *m, struct tcphdr *th, struct socket *so,
bbr->rc_timer_first = 1;
bbr_timer_cancel(bbr,
__LINE__, bbr->r_ctl.rc_rcvtime);
INP_INFO_RLOCK_ASSERT(&V_tcbinfo);
INP_WLOCK_ASSERT(tp->t_inpcb);
tcp_twstart(tp);
return (1);
@ -9619,7 +9618,6 @@ bbr_check_data_after_close(struct mbuf *m, struct tcp_bbr *bbr,
struct tcpcb *tp, int32_t * tlen, struct tcphdr *th, struct socket *so)
{
INP_INFO_RLOCK_ASSERT(&V_tcbinfo);
if (bbr->rc_allow_data_af_clo == 0) {
close_now:
tp = tcp_close(tp);
@ -9861,7 +9859,6 @@ bbr_do_closing(struct mbuf *m, struct tcphdr *th, struct socket *so,
return (ret_val);
}
if (ourfinisacked) {
INP_INFO_RLOCK_ASSERT(&V_tcbinfo);
tcp_twstart(tp);
m_freem(m);
return (1);
@ -9974,7 +9971,6 @@ bbr_do_lastack(struct mbuf *m, struct tcphdr *th, struct socket *so,
return (ret_val);
}
if (ourfinisacked) {
INP_INFO_RLOCK_ASSERT(&V_tcbinfo);
tp = tcp_close(tp);
ctf_do_drop(m, tp);
return (1);

17
sys/netinet/tcp_stacks/rack.c
View File

@ -5875,7 +5875,6 @@ rack_process_data(struct mbuf *m, struct tcphdr *th, struct socket *so,
case TCPS_FIN_WAIT_2:
rack_timer_cancel(tp, rack,
rack->r_ctl.rc_rcvtime, __LINE__);
INP_INFO_RLOCK_ASSERT(&V_tcbinfo);
tcp_twstart(tp);
return (1);
}
@ -6353,7 +6352,6 @@ rack_do_syn_sent(struct mbuf *m, struct tcphdr *th, struct socket *so,
tp->t_flags |= (TF_ACKNOW | TF_NEEDSYN);
tcp_state_change(tp, TCPS_SYN_RECEIVED);
}
INP_INFO_RLOCK_ASSERT(&V_tcbinfo);
INP_WLOCK_ASSERT(tp->t_inpcb);
/*
* Advance th->th_seq to correspond to first data byte. If data,
@ -6847,7 +6845,6 @@ rack_check_data_after_close(struct mbuf *m,
{
struct tcp_rack *rack;
INP_INFO_RLOCK_ASSERT(&V_tcbinfo);
rack = (struct tcp_rack *)tp->t_fb_ptr;
if (rack->rc_allow_data_af_clo == 0) {
close_now:
@ -7079,7 +7076,6 @@ rack_do_closing(struct mbuf *m, struct tcphdr *th, struct socket *so,
return (ret_val);
}
if (ourfinisacked) {
INP_INFO_RLOCK_ASSERT(&V_tcbinfo);
tcp_twstart(tp);
m_freem(m);
return (1);
@ -7187,7 +7183,6 @@ rack_do_lastack(struct mbuf *m, struct tcphdr *th, struct socket *so,
return (ret_val);
}
if (ourfinisacked) {
INP_INFO_RLOCK_ASSERT(&V_tcbinfo);
tp = tcp_close(tp);
ctf_do_drop(m, tp);
return (1);
@ -7650,16 +7645,8 @@ rack_do_segment_nounlock(struct mbuf *m, struct tcphdr *th, struct socket *so,
kern_prefetch(rack, &prev_state);
prev_state = 0;
thflags = th->th_flags;
/*
* If this is either a state-changing packet or current state isn't
* established, we require a read lock on tcbinfo. Otherwise, we
* allow the tcbinfo to be in either locked or unlocked, as the
* caller may have unnecessarily acquired a lock due to a race.
*/
if ((thflags & (TH_SYN | TH_FIN | TH_RST)) != 0 ||
tp->t_state != TCPS_ESTABLISHED) {
INP_INFO_RLOCK_ASSERT(&V_tcbinfo);
}
NET_EPOCH_ASSERT();
INP_WLOCK_ASSERT(tp->t_inpcb);
KASSERT(tp->t_state > TCPS_LISTEN, ("%s: TCPS_LISTEN",
__func__));

17
sys/netinet/tcp_stacks/rack_bbr_common.c
View File

@ -253,7 +253,6 @@ ctf_process_inbound_raw(struct tcpcb *tp, struct socket *so, struct mbuf *m, int
*/
struct mbuf *m_save;
struct ether_header *eh;
struct epoch_tracker et;
struct tcphdr *th;
#ifdef INET6
struct ip6_hdr *ip6 = NULL; /* Keep compiler happy. */
@ -268,14 +267,8 @@ ctf_process_inbound_raw(struct tcpcb *tp, struct socket *so, struct mbuf *m, int
uint16_t drop_hdrlen;
uint8_t iptos, no_vn=0, bpf_req=0;
/*
* This is a bit deceptive, we get the
* "info epoch" which is really the network
* epoch. This covers us on both any INP
* type change but also if the ifp goes
* away it covers us as well.
*/
INP_INFO_RLOCK_ET(&V_tcbinfo, et);
NET_EPOCH_ASSERT();
if (m && m->m_pkthdr.rcvif)
ifp = m->m_pkthdr.rcvif;
else
@ -445,7 +438,6 @@ ctf_process_inbound_raw(struct tcpcb *tp, struct socket *so, struct mbuf *m, int
}
if (no_vn == 0)
CURVNET_RESTORE();
INP_INFO_RUNLOCK_ET(&V_tcbinfo, et);
return(retval);
}
skipped_pkt:
@ -453,7 +445,6 @@ ctf_process_inbound_raw(struct tcpcb *tp, struct socket *so, struct mbuf *m, int
}
if (no_vn == 0)
CURVNET_RESTORE();
INP_INFO_RUNLOCK_ET(&V_tcbinfo, et);
return(retval);
}
@ -680,7 +671,6 @@ ctf_process_rst(struct mbuf *m, struct tcphdr *th, struct socket *so, struct tcp
SEQ_LT(th->th_seq, tp->last_ack_sent + tp->rcv_wnd)) ||
(tp->rcv_wnd == 0 && tp->last_ack_sent == th->th_seq)) {
INP_INFO_RLOCK_ASSERT(&V_tcbinfo);
KASSERT(tp->t_state != TCPS_SYN_SENT,
("%s: TH_RST for TCPS_SYN_SENT th %p tp %p",
__func__, th, tp));
@ -732,7 +722,8 @@ ctf_process_rst(struct mbuf *m, struct tcphdr *th, struct socket *so, struct tcp
void
ctf_challenge_ack(struct mbuf *m, struct tcphdr *th, struct tcpcb *tp, int32_t * ret_val)
{
INP_INFO_RLOCK_ASSERT(&V_tcbinfo);
NET_EPOCH_ASSERT();
TCPSTAT_INC(tcps_badsyn);
if (V_tcp_insecure_syn &&