diff options
Diffstat (limited to 'sys/netinet/tcp_timewait.c')
| -rw-r--r-- | sys/netinet/tcp_timewait.c | 39 |
1 files changed, 22 insertions, 17 deletions
diff --git a/sys/netinet/tcp_timewait.c b/sys/netinet/tcp_timewait.c index 8139c6d..73d23d8 100644 --- a/sys/netinet/tcp_timewait.c +++ b/sys/netinet/tcp_timewait.c @@ -201,10 +201,10 @@ tcp_tw_destroy(void) { struct tcptw *tw; - INP_INFO_WLOCK(&V_tcbinfo); + INP_INFO_RLOCK(&V_tcbinfo); while ((tw = TAILQ_FIRST(&V_twq_2msl)) != NULL) tcp_twclose(tw, 0); - INP_INFO_WUNLOCK(&V_tcbinfo); + INP_INFO_RUNLOCK(&V_tcbinfo); TW_LOCK_DESTROY(V_tw_lock); uma_zdestroy(V_tcptw_zone); @@ -227,7 +227,7 @@ tcp_twstart(struct tcpcb *tp) int isipv6 = inp->inp_inc.inc_flags & INC_ISIPV6; #endif - INP_INFO_WLOCK_ASSERT(&V_tcbinfo); + INP_INFO_RLOCK_ASSERT(&V_tcbinfo); INP_WLOCK_ASSERT(inp); /* A dropped inp should never transition to TIME_WAIT state. */ @@ -268,8 +268,8 @@ tcp_twstart(struct tcpcb *tp) * allowed. Remove a connection from TIMEWAIT queue in LRU * fashion to make room for this connection. * - * pcbinfo lock is needed here to prevent deadlock as - * two inpcb locks can be acquired simultaneously. + * XXX: Check if it possible to always have enough room + * in advance based on guarantees provided by uma_zalloc(). */ tw = tcp_tw_2msl_scan(1); if (tw == NULL) { @@ -380,7 +380,7 @@ tcp_twrecycleable(struct tcptw *tw) tcp_seq new_iss = tw->iss; tcp_seq new_irs = tw->irs; - INP_INFO_WLOCK_ASSERT(&V_tcbinfo); + INP_INFO_RLOCK_ASSERT(&V_tcbinfo); new_iss += (ticks - tw->t_starttime) * (ISN_BYTES_PER_SECOND / hz); new_irs += (ticks - tw->t_starttime) * (MS_ISN_BYTES_PER_SECOND / hz); @@ -403,7 +403,7 @@ tcp_twcheck(struct inpcb *inp, struct tcpopt *to __unused, struct tcphdr *th, int thflags; tcp_seq seq; - INP_INFO_WLOCK_ASSERT(&V_tcbinfo); + INP_INFO_RLOCK_ASSERT(&V_tcbinfo); INP_WLOCK_ASSERT(inp); /* @@ -504,7 +504,7 @@ tcp_twclose(struct tcptw *tw, int reuse) inp = tw->tw_inpcb; KASSERT((inp->inp_flags & INP_TIMEWAIT), ("tcp_twclose: !timewait")); KASSERT(intotw(inp) == tw, ("tcp_twclose: inp_ppcb != tw")); - INP_INFO_WLOCK_ASSERT(&V_tcbinfo); /* in_pcbfree() */ + INP_INFO_RLOCK_ASSERT(&V_tcbinfo); /* in_pcbfree() */ INP_WLOCK_ASSERT(inp); tcp_tw_2msl_stop(tw, reuse); @@ -659,7 +659,7 @@ static void tcp_tw_2msl_reset(struct tcptw *tw, int rearm) { - INP_INFO_WLOCK_ASSERT(&V_tcbinfo); + INP_INFO_RLOCK_ASSERT(&V_tcbinfo); INP_WLOCK_ASSERT(tw->tw_inpcb); TW_WLOCK(V_tw_lock); @@ -677,7 +677,7 @@ tcp_tw_2msl_stop(struct tcptw *tw, int reuse) struct inpcb *inp; int released; - INP_INFO_WLOCK_ASSERT(&V_tcbinfo); + INP_INFO_RLOCK_ASSERT(&V_tcbinfo); TW_WLOCK(V_tw_lock); inp = tw->tw_inpcb; @@ -707,13 +707,18 @@ tcp_tw_2msl_scan(int reuse) #ifdef INVARIANTS if (reuse) { /* - * pcbinfo lock is needed in reuse case to prevent deadlock - * as two inpcb locks can be acquired simultaneously: + * Exclusive pcbinfo lock is not required in reuse case even if + * two inpcb locks can be acquired simultaneously: * - the inpcb transitioning to TIME_WAIT state in * tcp_tw_start(), * - the inpcb closed by tcp_twclose(). + * + * It is because only inpcbs in FIN_WAIT2 or CLOSING states can + * transition in TIME_WAIT state. Then a pcbcb cannot be in + * TIME_WAIT list and transitioning to TIME_WAIT state at same + * time. */ - INP_INFO_WLOCK_ASSERT(&V_tcbinfo); + INP_INFO_RLOCK_ASSERT(&V_tcbinfo); } #endif @@ -731,26 +736,26 @@ tcp_tw_2msl_scan(int reuse) in_pcbref(inp); TW_RUNLOCK(V_tw_lock); - if (INP_INFO_TRY_WLOCK(&V_tcbinfo)) { + if (INP_INFO_TRY_RLOCK(&V_tcbinfo)) { INP_WLOCK(inp); tw = intotw(inp); if (in_pcbrele_wlocked(inp)) { KASSERT(tw == NULL, ("%s: held last inp " "reference but tw not NULL", __func__)); - INP_INFO_WUNLOCK(&V_tcbinfo); + INP_INFO_RUNLOCK(&V_tcbinfo); continue; } if (tw == NULL) { /* tcp_twclose() has already been called */ INP_WUNLOCK(inp); - INP_INFO_WUNLOCK(&V_tcbinfo); + INP_INFO_RUNLOCK(&V_tcbinfo); continue; } tcp_twclose(tw, reuse); - INP_INFO_WUNLOCK(&V_tcbinfo); + INP_INFO_RUNLOCK(&V_tcbinfo); if (reuse) return tw; } else { |
