--- zzzz-none-000/linux-3.10.107/net/ipv4/inet_timewait_sock.c 2017-06-27 09:49:32.000000000 +0000 +++ scorpion-7490-727/linux-3.10.107/net/ipv4/inet_timewait_sock.c 2021-02-04 17:41:59.000000000 +0000 @@ -18,28 +18,6 @@ /** - * inet_twsk_unhash - unhash a timewait socket from established hash - * @tw: timewait socket - * - * unhash a timewait socket from established hash, if hashed. - * ehash lock must be held by caller. - * Returns 1 if caller should call inet_twsk_put() after lock release. - */ -int inet_twsk_unhash(struct inet_timewait_sock *tw) -{ - if (hlist_nulls_unhashed(&tw->tw_node)) - return 0; - - hlist_nulls_del_rcu(&tw->tw_node); - sk_nulls_node_init(&tw->tw_node); - /* - * We cannot call inet_twsk_put() ourself under lock, - * caller must call it for us. - */ - return 1; -} - -/** * inet_twsk_bind_unhash - unhash a timewait socket from bind hash * @tw: timewait socket * @hashinfo: hashinfo pointer @@ -48,35 +26,29 @@ * bind hash lock must be held by caller. * Returns 1 if caller should call inet_twsk_put() after lock release. */ -int inet_twsk_bind_unhash(struct inet_timewait_sock *tw, +void inet_twsk_bind_unhash(struct inet_timewait_sock *tw, struct inet_hashinfo *hashinfo) { struct inet_bind_bucket *tb = tw->tw_tb; if (!tb) - return 0; + return; __hlist_del(&tw->tw_bind_node); tw->tw_tb = NULL; inet_bind_bucket_destroy(hashinfo->bind_bucket_cachep, tb); - /* - * We cannot call inet_twsk_put() ourself under lock, - * caller must call it for us. - */ - return 1; + __sock_put((struct sock *)tw); } /* Must be called with locally disabled BHs. */ -static void __inet_twsk_kill(struct inet_timewait_sock *tw, - struct inet_hashinfo *hashinfo) +static void inet_twsk_kill(struct inet_timewait_sock *tw) { - struct inet_bind_hashbucket *bhead; - int refcnt; - /* Unlink from established hashes. */ + struct inet_hashinfo *hashinfo = tw->tw_dr->hashinfo; spinlock_t *lock = inet_ehash_lockp(hashinfo, tw->tw_hash); + struct inet_bind_hashbucket *bhead; spin_lock(lock); - refcnt = inet_twsk_unhash(tw); + sk_nulls_del_node_init_rcu((struct sock *)tw); spin_unlock(lock); /* Disassociate with bind bucket. */ @@ -84,29 +56,20 @@ hashinfo->bhash_size)]; spin_lock(&bhead->lock); - refcnt += inet_twsk_bind_unhash(tw, hashinfo); + inet_twsk_bind_unhash(tw, hashinfo); spin_unlock(&bhead->lock); -#ifdef SOCK_REFCNT_DEBUG - if (atomic_read(&tw->tw_refcnt) != 1) { - pr_debug("%s timewait_sock %p refcnt=%d\n", - tw->tw_prot->name, tw, atomic_read(&tw->tw_refcnt)); - } -#endif - while (refcnt) { - inet_twsk_put(tw); - refcnt--; - } + atomic_dec(&tw->tw_dr->tw_count); + inet_twsk_put(tw); } -static noinline void inet_twsk_free(struct inet_timewait_sock *tw) +void inet_twsk_free(struct inet_timewait_sock *tw) { struct module *owner = tw->tw_prot->owner; twsk_destructor((struct sock *)tw); #ifdef SOCK_REFCNT_DEBUG pr_debug("%s timewait_sock %p released\n", tw->tw_prot->name, tw); #endif - release_net(twsk_net(tw)); kmem_cache_free(tw->tw_prot->twsk_prot->twsk_slab, tw); module_put(owner); } @@ -118,6 +81,18 @@ } EXPORT_SYMBOL_GPL(inet_twsk_put); +static void inet_twsk_add_node_rcu(struct inet_timewait_sock *tw, + struct hlist_nulls_head *list) +{ + hlist_nulls_add_head_rcu(&tw->tw_node, list); +} + +static void inet_twsk_add_bind_node(struct inet_timewait_sock *tw, + struct hlist_head *list) +{ + hlist_add_head(&tw->tw_bind_node, list); +} + /* * Enter the time wait state. This is called with locally disabled BH. * Essentially we whip up a timewait bucket, copy the relevant info into it @@ -146,40 +121,55 @@ spin_lock(lock); /* - * Step 2: Hash TW into TIMEWAIT chain. - * Should be done before removing sk from established chain - * because readers are lockless and search established first. + * Step 2: Hash TW into tcp ehash chain. + * Notes : + * - tw_refcnt is set to 4 because : + * - We have one reference from bhash chain. + * - We have one reference from ehash chain. + * - We have one reference from timer. + * - One reference for ourself (our caller will release it). + * We can use atomic_set() because prior spin_lock()/spin_unlock() + * committed into memory all tw fields. */ - inet_twsk_add_node_rcu(tw, &ehead->twchain); + atomic_set(&tw->tw_refcnt, 4); + inet_twsk_add_node_rcu(tw, &ehead->chain); - /* Step 3: Remove SK from established hash. */ + /* Step 3: Remove SK from hash chain */ if (__sk_nulls_del_node_init_rcu(sk)) sock_prot_inuse_add(sock_net(sk), sk->sk_prot, -1); - /* - * Notes : - * - We initially set tw_refcnt to 0 in inet_twsk_alloc() - * - We add one reference for the bhash link - * - We add one reference for the ehash link - * - We want this refcnt update done before allowing other - * threads to find this tw in ehash chain. - */ - atomic_add(1 + 1 + 1, &tw->tw_refcnt); - spin_unlock(lock); } EXPORT_SYMBOL_GPL(__inet_twsk_hashdance); -struct inet_timewait_sock *inet_twsk_alloc(const struct sock *sk, const int state) +static void tw_timer_handler(unsigned long data) { - struct inet_timewait_sock *tw = - kmem_cache_alloc(sk->sk_prot_creator->twsk_prot->twsk_slab, - GFP_ATOMIC); - if (tw != NULL) { + struct inet_timewait_sock *tw = (struct inet_timewait_sock *)data; + + if (tw->tw_kill) + NET_INC_STATS_BH(twsk_net(tw), LINUX_MIB_TIMEWAITKILLED); + else + NET_INC_STATS_BH(twsk_net(tw), LINUX_MIB_TIMEWAITED); + inet_twsk_kill(tw); +} + +struct inet_timewait_sock *inet_twsk_alloc(const struct sock *sk, + struct inet_timewait_death_row *dr, + const int state) +{ + struct inet_timewait_sock *tw; + + if (atomic_read(&dr->tw_count) >= dr->sysctl_max_tw_buckets) + return NULL; + + tw = kmem_cache_alloc(sk->sk_prot_creator->twsk_prot->twsk_slab, + GFP_ATOMIC); + if (tw) { const struct inet_sock *inet = inet_sk(sk); kmemcheck_annotate_bitfield(tw, flags); + tw->tw_dr = dr; /* Give us an identity. */ tw->tw_daddr = inet->inet_daddr; tw->tw_rcv_saddr = inet->inet_rcv_saddr; @@ -196,14 +186,16 @@ tw->tw_ipv6only = 0; tw->tw_transparent = inet->transparent; tw->tw_prot = sk->sk_prot_creator; - twsk_net_set(tw, hold_net(sock_net(sk))); + atomic64_set(&tw->tw_cookie, atomic64_read(&sk->sk_cookie)); + twsk_net_set(tw, sock_net(sk)); + setup_timer(&tw->tw_timer, tw_timer_handler, (unsigned long)tw); /* * Because we use RCU lookups, we should not set tw_refcnt * to a non null value before everything is setup for this * timewait socket. */ atomic_set(&tw->tw_refcnt, 0); - inet_twsk_dead_node_init(tw); + __module_get(tw->tw_prot->owner); } @@ -211,139 +203,24 @@ } EXPORT_SYMBOL_GPL(inet_twsk_alloc); -/* Returns non-zero if quota exceeded. */ -static int inet_twdr_do_twkill_work(struct inet_timewait_death_row *twdr, - const int slot) -{ - struct inet_timewait_sock *tw; - unsigned int killed; - int ret; - - /* NOTE: compare this to previous version where lock - * was released after detaching chain. It was racy, - * because tw buckets are scheduled in not serialized context - * in 2.3 (with netfilter), and with softnet it is common, because - * soft irqs are not sequenced. - */ - killed = 0; - ret = 0; -rescan: - inet_twsk_for_each_inmate(tw, &twdr->cells[slot]) { - __inet_twsk_del_dead_node(tw); - spin_unlock(&twdr->death_lock); - __inet_twsk_kill(tw, twdr->hashinfo); -#ifdef CONFIG_NET_NS - NET_INC_STATS_BH(twsk_net(tw), LINUX_MIB_TIMEWAITED); -#endif - inet_twsk_put(tw); - killed++; - spin_lock(&twdr->death_lock); - if (killed > INET_TWDR_TWKILL_QUOTA) { - ret = 1; - break; - } - - /* While we dropped twdr->death_lock, another cpu may have - * killed off the next TW bucket in the list, therefore - * do a fresh re-read of the hlist head node with the - * lock reacquired. We still use the hlist traversal - * macro in order to get the prefetches. - */ - goto rescan; - } - - twdr->tw_count -= killed; -#ifndef CONFIG_NET_NS - NET_ADD_STATS_BH(&init_net, LINUX_MIB_TIMEWAITED, killed); -#endif - return ret; -} - -void inet_twdr_hangman(unsigned long data) -{ - struct inet_timewait_death_row *twdr; - unsigned int need_timer; - - twdr = (struct inet_timewait_death_row *)data; - spin_lock(&twdr->death_lock); - - if (twdr->tw_count == 0) - goto out; - - need_timer = 0; - if (inet_twdr_do_twkill_work(twdr, twdr->slot)) { - twdr->thread_slots |= (1 << twdr->slot); - schedule_work(&twdr->twkill_work); - need_timer = 1; - } else { - /* We purged the entire slot, anything left? */ - if (twdr->tw_count) - need_timer = 1; - twdr->slot = ((twdr->slot + 1) & (INET_TWDR_TWKILL_SLOTS - 1)); - } - if (need_timer) - mod_timer(&twdr->tw_timer, jiffies + twdr->period); -out: - spin_unlock(&twdr->death_lock); -} -EXPORT_SYMBOL_GPL(inet_twdr_hangman); - -void inet_twdr_twkill_work(struct work_struct *work) -{ - struct inet_timewait_death_row *twdr = - container_of(work, struct inet_timewait_death_row, twkill_work); - int i; - - BUILD_BUG_ON((INET_TWDR_TWKILL_SLOTS - 1) > - (sizeof(twdr->thread_slots) * 8)); - - while (twdr->thread_slots) { - spin_lock_bh(&twdr->death_lock); - for (i = 0; i < INET_TWDR_TWKILL_SLOTS; i++) { - if (!(twdr->thread_slots & (1 << i))) - continue; - - while (inet_twdr_do_twkill_work(twdr, i) != 0) { - if (need_resched()) { - spin_unlock_bh(&twdr->death_lock); - schedule(); - spin_lock_bh(&twdr->death_lock); - } - } - - twdr->thread_slots &= ~(1 << i); - } - spin_unlock_bh(&twdr->death_lock); - } -} -EXPORT_SYMBOL_GPL(inet_twdr_twkill_work); - /* These are always called from BH context. See callers in * tcp_input.c to verify this. */ -/* This is for handling early-kills of TIME_WAIT sockets. */ -void inet_twsk_deschedule(struct inet_timewait_sock *tw, - struct inet_timewait_death_row *twdr) -{ - spin_lock(&twdr->death_lock); - if (inet_twsk_del_dead_node(tw)) { - inet_twsk_put(tw); - if (--twdr->tw_count == 0) - del_timer(&twdr->tw_timer); - } - spin_unlock(&twdr->death_lock); - __inet_twsk_kill(tw, twdr->hashinfo); +/* This is for handling early-kills of TIME_WAIT sockets. + * Warning : consume reference. + * Caller should not access tw anymore. + */ +void inet_twsk_deschedule_put(struct inet_timewait_sock *tw) +{ + if (del_timer_sync(&tw->tw_timer)) + inet_twsk_kill(tw); + inet_twsk_put(tw); } -EXPORT_SYMBOL(inet_twsk_deschedule); +EXPORT_SYMBOL(inet_twsk_deschedule_put); -void inet_twsk_schedule(struct inet_timewait_sock *tw, - struct inet_timewait_death_row *twdr, - const int timeo, const int timewait_len) +void __inet_twsk_schedule(struct inet_timewait_sock *tw, int timeo, bool rearm) { - struct hlist_head *list; - int slot; - /* timeout := RTO * 3.5 * * 3.5 = 1+2+0.5 to wait for two retransmits. @@ -368,114 +245,16 @@ * is greater than TS tick!) and detect old duplicates with help * of PAWS. */ - slot = (timeo + (1 << INET_TWDR_RECYCLE_TICK) - 1) >> INET_TWDR_RECYCLE_TICK; - - spin_lock(&twdr->death_lock); - - /* Unlink it, if it was scheduled */ - if (inet_twsk_del_dead_node(tw)) - twdr->tw_count--; - else - atomic_inc(&tw->tw_refcnt); - if (slot >= INET_TWDR_RECYCLE_SLOTS) { - /* Schedule to slow timer */ - if (timeo >= timewait_len) { - slot = INET_TWDR_TWKILL_SLOTS - 1; - } else { - slot = DIV_ROUND_UP(timeo, twdr->period); - if (slot >= INET_TWDR_TWKILL_SLOTS) - slot = INET_TWDR_TWKILL_SLOTS - 1; - } - tw->tw_ttd = jiffies + timeo; - slot = (twdr->slot + slot) & (INET_TWDR_TWKILL_SLOTS - 1); - list = &twdr->cells[slot]; + tw->tw_kill = timeo <= 4*HZ; + if (!rearm) { + BUG_ON(mod_timer_pinned(&tw->tw_timer, jiffies + timeo)); + atomic_inc(&tw->tw_dr->tw_count); } else { - tw->tw_ttd = jiffies + (slot << INET_TWDR_RECYCLE_TICK); - - if (twdr->twcal_hand < 0) { - twdr->twcal_hand = 0; - twdr->twcal_jiffie = jiffies; - twdr->twcal_timer.expires = twdr->twcal_jiffie + - (slot << INET_TWDR_RECYCLE_TICK); - add_timer(&twdr->twcal_timer); - } else { - if (time_after(twdr->twcal_timer.expires, - jiffies + (slot << INET_TWDR_RECYCLE_TICK))) - mod_timer(&twdr->twcal_timer, - jiffies + (slot << INET_TWDR_RECYCLE_TICK)); - slot = (twdr->twcal_hand + slot) & (INET_TWDR_RECYCLE_SLOTS - 1); - } - list = &twdr->twcal_row[slot]; - } - - hlist_add_head(&tw->tw_death_node, list); - - if (twdr->tw_count++ == 0) - mod_timer(&twdr->tw_timer, jiffies + twdr->period); - spin_unlock(&twdr->death_lock); -} -EXPORT_SYMBOL_GPL(inet_twsk_schedule); - -void inet_twdr_twcal_tick(unsigned long data) -{ - struct inet_timewait_death_row *twdr; - int n, slot; - unsigned long j; - unsigned long now = jiffies; - int killed = 0; - int adv = 0; - - twdr = (struct inet_timewait_death_row *)data; - - spin_lock(&twdr->death_lock); - if (twdr->twcal_hand < 0) - goto out; - - slot = twdr->twcal_hand; - j = twdr->twcal_jiffie; - - for (n = 0; n < INET_TWDR_RECYCLE_SLOTS; n++) { - if (time_before_eq(j, now)) { - struct hlist_node *safe; - struct inet_timewait_sock *tw; - - inet_twsk_for_each_inmate_safe(tw, safe, - &twdr->twcal_row[slot]) { - __inet_twsk_del_dead_node(tw); - __inet_twsk_kill(tw, twdr->hashinfo); -#ifdef CONFIG_NET_NS - NET_INC_STATS_BH(twsk_net(tw), LINUX_MIB_TIMEWAITKILLED); -#endif - inet_twsk_put(tw); - killed++; - } - } else { - if (!adv) { - adv = 1; - twdr->twcal_jiffie = j; - twdr->twcal_hand = slot; - } - - if (!hlist_empty(&twdr->twcal_row[slot])) { - mod_timer(&twdr->twcal_timer, j); - goto out; - } - } - j += 1 << INET_TWDR_RECYCLE_TICK; - slot = (slot + 1) & (INET_TWDR_RECYCLE_SLOTS - 1); + mod_timer_pending(&tw->tw_timer, jiffies + timeo); } - twdr->twcal_hand = -1; - -out: - if ((twdr->tw_count -= killed) == 0) - del_timer(&twdr->tw_timer); -#ifndef CONFIG_NET_NS - NET_ADD_STATS_BH(&init_net, LINUX_MIB_TIMEWAITKILLED, killed); -#endif - spin_unlock(&twdr->death_lock); } -EXPORT_SYMBOL_GPL(inet_twdr_twcal_tick); +EXPORT_SYMBOL_GPL(__inet_twsk_schedule); void inet_twsk_purge(struct inet_hashinfo *hashinfo, struct inet_timewait_death_row *twdr, int family) @@ -488,9 +267,12 @@ for (slot = 0; slot <= hashinfo->ehash_mask; slot++) { struct inet_ehash_bucket *head = &hashinfo->ehash[slot]; restart_rcu: + cond_resched(); rcu_read_lock(); restart: - sk_nulls_for_each_rcu(sk, node, &head->twchain) { + sk_nulls_for_each_rcu(sk, node, &head->chain) { + if (sk->sk_state != TCP_TIME_WAIT) + continue; tw = inet_twsk(sk); if ((tw->tw_family != family) || atomic_read(&twsk_net(tw)->count)) @@ -507,9 +289,8 @@ rcu_read_unlock(); local_bh_disable(); - inet_twsk_deschedule(tw, twdr); + inet_twsk_deschedule_put(tw); local_bh_enable(); - inet_twsk_put(tw); goto restart_rcu; } /* If the nulls value we got at the end of this lookup is