Commit 696ab2d3 authored by Arnaldo Carvalho de Melo's avatar Arnaldo Carvalho de Melo Committed by David S. Miller
Browse files

[TIMEWAIT]: Move inet_timewait_death_row routines to net/ipv4/inet_timewait_sock.c 



Also export the ones that will be used in the next changeset, when
DCCP uses this infrastructure.

Signed-off-by: default avatarArnaldo Carvalho de Melo <acme@mandriva.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 295ff7ed

include/net/inet_timewait_sock.h

+10 −0
Original line number Diff line number Diff line
@@ -82,6 +82,10 @@ struct inet_timewait_death_row { 
	int			sysctl_max_tw_buckets;

};



extern void inet_twdr_hangman(unsigned long data);

extern void inet_twdr_twkill_work(void *data);

extern void inet_twdr_twcal_tick(unsigned long data);



#if (BITS_PER_LONG == 64)

#define INET_TIMEWAIT_ADDRCMP_ALIGN_BYTES 8

#else
@@ -206,4 +210,10 @@ extern void __inet_twsk_kill(struct inet_timewait_sock *tw, 
extern void __inet_twsk_hashdance(struct inet_timewait_sock *tw,

				  struct sock *sk,

				  struct inet_hashinfo *hashinfo);



extern void inet_twsk_schedule(struct inet_timewait_sock *tw,

			       struct inet_timewait_death_row *twdr,

			       const int timeo, const int timewait_len);

extern void inet_twsk_deschedule(struct inet_timewait_sock *tw,

				 struct inet_timewait_death_row *twdr);

#endif	/* _INET_TIMEWAIT_SOCK_ */

include/net/tcp.h

+0 −2
Original line number Diff line number Diff line
@@ -44,8 +44,6 @@ extern struct inet_hashinfo tcp_hashinfo; 


extern atomic_t tcp_orphan_count;

extern void tcp_time_wait(struct sock *sk, int state, int timeo);

extern void inet_twsk_deschedule(struct inet_timewait_sock *tw,

				 struct inet_timewait_death_row *twdr);



#define MAX_TCP_HEADER	(128 + MAX_HEADER)

net/ipv4/inet_timewait_sock.c

+270 −0
Original line number Diff line number Diff line
@@ -12,6 +12,7 @@ 


#include <net/inet_hashtables.h>

#include <net/inet_timewait_sock.h>

#include <net/ip.h>



/* Must be called with locally disabled BHs. */

void __inet_twsk_kill(struct inet_timewait_sock *tw, struct inet_hashinfo *hashinfo)
@@ -85,6 +86,8 @@ void __inet_twsk_hashdance(struct inet_timewait_sock *tw, struct sock *sk, 
	write_unlock(&ehead->lock);

}



EXPORT_SYMBOL_GPL(__inet_twsk_hashdance);



struct inet_timewait_sock *inet_twsk_alloc(const struct sock *sk, const int state)

{

	struct inet_timewait_sock *tw = kmem_cache_alloc(sk->sk_prot_creator->twsk_slab,
@@ -112,3 +115,270 @@ struct inet_timewait_sock *inet_twsk_alloc(const struct sock *sk, const int stat 


	return tw;

}



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;

	struct hlist_node *node;

	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, node, &twdr->cells[slot]) {

		__inet_twsk_del_dead_node(tw);

		spin_unlock(&twdr->death_lock);

		__inet_twsk_kill(tw, twdr->hashinfo);

		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;

	NET_ADD_STATS_BH(LINUX_MIB_TIMEWAITED, killed);



	return ret;

}



void inet_twdr_hangman(unsigned long data)

{

	struct inet_timewait_death_row *twdr;

	int unsigned 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);

		mb();

		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);



extern void twkill_slots_invalid(void);



void inet_twdr_twkill_work(void *data)

{

	struct inet_timewait_death_row *twdr = data;

	int i;



	if ((INET_TWDR_TWKILL_SLOTS - 1) > (sizeof(twdr->thread_slots) * 8))

		twkill_slots_invalid();



	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);

}



EXPORT_SYMBOL(inet_twsk_deschedule);



void inet_twsk_schedule(struct inet_timewait_sock *tw,

		       struct inet_timewait_death_row *twdr,

		       const int timeo, const int timewait_len)

{

	struct hlist_head *list;

	int slot;



	/* timeout := RTO * 3.5

	 *

	 * 3.5 = 1+2+0.5 to wait for two retransmits.

	 *

	 * RATIONALE: if FIN arrived and we entered TIME-WAIT state,

	 * our ACK acking that FIN can be lost. If N subsequent retransmitted

	 * FINs (or previous seqments) are lost (probability of such event

	 * is p^(N+1), where p is probability to lose single packet and

	 * time to detect the loss is about RTO*(2^N - 1) with exponential

	 * backoff). Normal timewait length is calculated so, that we

	 * waited at least for one retransmitted FIN (maximal RTO is 120sec).

	 * [ BTW Linux. following BSD, violates this requirement waiting

	 *   only for 60sec, we should wait at least for 240 secs.

	 *   Well, 240 consumes too much of resources 8)

	 * ]

	 * This interval is not reduced to catch old duplicate and

	 * responces to our wandering segments living for two MSLs.

	 * However, if we use PAWS to detect

	 * old duplicates, we can reduce the interval to bounds required

	 * by RTO, rather than MSL. So, if peer understands PAWS, we

	 * kill tw bucket after 3.5*RTO (it is important that this number

	 * 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 = (timeo + twdr->period - 1) / 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];

	} 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 *node, *safe;

			struct inet_timewait_sock *tw;



			inet_twsk_for_each_inmate_safe(tw, node, safe,

						       &twdr->twcal_row[slot]) {

				__inet_twsk_del_dead_node(tw);

				__inet_twsk_kill(tw, twdr->hashinfo);

				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);

	}

	twdr->twcal_hand = -1;



out:

	if ((twdr->tw_count -= killed) == 0)

		del_timer(&twdr->tw_timer);

	NET_ADD_STATS_BH(LINUX_MIB_TIMEWAITKILLED, killed);

	spin_unlock(&twdr->death_lock);

}



EXPORT_SYMBOL_GPL(inet_twdr_twcal_tick);

net/ipv4/tcp_minisocks.c

+10 −271
Original line number Diff line number Diff line
@@ -35,12 +35,6 @@ 
#define SYNC_INIT 1

#endif



/* New-style handling of TIME_WAIT sockets. */



static void inet_twdr_hangman(unsigned long data);

static void inet_twdr_twkill_work(void *data);

static void inet_twdr_twcal_tick(unsigned long data);



int sysctl_tcp_syncookies = SYNC_INIT; 

int sysctl_tcp_abort_on_overflow;
@@ -63,10 +57,6 @@ struct inet_timewait_death_row tcp_death_row = { 


EXPORT_SYMBOL_GPL(tcp_death_row);



static void inet_twsk_schedule(struct inet_timewait_sock *tw,

			       struct inet_timewait_death_row *twdr,

			       const int timeo);



static __inline__ int tcp_in_window(u32 seq, u32 end_seq, u32 s_win, u32 e_win)

{

	if (seq == s_win)
@@ -173,9 +163,11 @@ tcp_timewait_state_process(struct inet_timewait_sock *tw, struct sk_buff *skb, 
		if (tw->tw_family == AF_INET &&

		    tcp_death_row.sysctl_tw_recycle && tcptw->tw_ts_recent_stamp &&

		    tcp_v4_tw_remember_stamp(tw))

			inet_twsk_schedule(tw, &tcp_death_row, tw->tw_timeout);

			inet_twsk_schedule(tw, &tcp_death_row, tw->tw_timeout,

					   TCP_TIMEWAIT_LEN);

		else

			inet_twsk_schedule(tw, &tcp_death_row, TCP_TIMEWAIT_LEN);

			inet_twsk_schedule(tw, &tcp_death_row, TCP_TIMEWAIT_LEN,

					   TCP_TIMEWAIT_LEN);

		return TCP_TW_ACK;

	}
@@ -213,7 +205,8 @@ tcp_timewait_state_process(struct inet_timewait_sock *tw, struct sk_buff *skb, 
				return TCP_TW_SUCCESS;

			}

		}

		inet_twsk_schedule(tw, &tcp_death_row, TCP_TIMEWAIT_LEN);

		inet_twsk_schedule(tw, &tcp_death_row, TCP_TIMEWAIT_LEN,

				   TCP_TIMEWAIT_LEN);



		if (tmp_opt.saw_tstamp) {

			tcptw->tw_ts_recent	  = tmp_opt.rcv_tsval;
@@ -263,7 +256,8 @@ tcp_timewait_state_process(struct inet_timewait_sock *tw, struct sk_buff *skb, 
		 * Do not reschedule in the last case.

		 */

		if (paws_reject || th->ack)

			inet_twsk_schedule(tw, &tcp_death_row, TCP_TIMEWAIT_LEN);

			inet_twsk_schedule(tw, &tcp_death_row, TCP_TIMEWAIT_LEN,

					   TCP_TIMEWAIT_LEN);



		/* Send ACK. Note, we do not put the bucket,

		 * it will be released by caller.
@@ -326,7 +320,8 @@ void tcp_time_wait(struct sock *sk, int state, int timeo) 
				timeo = TCP_TIMEWAIT_LEN;

		}



		inet_twsk_schedule(tw, &tcp_death_row, timeo);

		inet_twsk_schedule(tw, &tcp_death_row, timeo,

				   TCP_TIMEWAIT_LEN);

		inet_twsk_put(tw);

	} else {

		/* Sorry, if we're out of memory, just CLOSE this
@@ -341,261 +336,6 @@ void tcp_time_wait(struct sock *sk, int state, int timeo) 
	tcp_done(sk);

}



/* 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;

	struct hlist_node *node;

	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, node, &twdr->cells[slot]) {

		__inet_twsk_del_dead_node(tw);

		spin_unlock(&twdr->death_lock);

		__inet_twsk_kill(tw, twdr->hashinfo);

		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;

	NET_ADD_STATS_BH(LINUX_MIB_TIMEWAITED, killed);



	return ret;

}



static void inet_twdr_hangman(unsigned long data)

{

	struct inet_timewait_death_row *twdr;

	int unsigned 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);

		mb();

		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);

}



extern void twkill_slots_invalid(void);



static void inet_twdr_twkill_work(void *data)

{

	struct inet_timewait_death_row *twdr = data;

	int i;



	if ((INET_TWDR_TWKILL_SLOTS - 1) > (sizeof(twdr->thread_slots) * 8))

		twkill_slots_invalid();



	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);

	}

}



/* 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);

}



static void inet_twsk_schedule(struct inet_timewait_sock *tw,

			       struct inet_timewait_death_row *twdr,

			       const int timeo)

{

	struct hlist_head *list;

	int slot;



	/* timeout := RTO * 3.5

	 *

	 * 3.5 = 1+2+0.5 to wait for two retransmits.

	 *

	 * RATIONALE: if FIN arrived and we entered TIME-WAIT state,

	 * our ACK acking that FIN can be lost. If N subsequent retransmitted

	 * FINs (or previous seqments) are lost (probability of such event

	 * is p^(N+1), where p is probability to lose single packet and

	 * time to detect the loss is about RTO*(2^N - 1) with exponential

	 * backoff). Normal timewait length is calculated so, that we

	 * waited at least for one retransmitted FIN (maximal RTO is 120sec).

	 * [ BTW Linux. following BSD, violates this requirement waiting

	 *   only for 60sec, we should wait at least for 240 secs.

	 *   Well, 240 consumes too much of resources 8)

	 * ]

	 * This interval is not reduced to catch old duplicate and

	 * responces to our wandering segments living for two MSLs.

	 * However, if we use PAWS to detect

	 * old duplicates, we can reduce the interval to bounds required

	 * by RTO, rather than MSL. So, if peer understands PAWS, we

	 * kill tw bucket after 3.5*RTO (it is important that this number

	 * 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 >= TCP_TIMEWAIT_LEN) {

			slot = INET_TWDR_TWKILL_SLOTS - 1;

		} else {

			slot = (timeo + twdr->period - 1) / 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];

	} 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);

}



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 *node, *safe;

			struct inet_timewait_sock *tw;



			inet_twsk_for_each_inmate_safe(tw, node, safe,

						       &twdr->twcal_row[slot]) {

				__inet_twsk_del_dead_node(tw);

				__inet_twsk_kill(tw, twdr->hashinfo);

				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);

	}

	twdr->twcal_hand = -1;



out:

	if ((twdr->tw_count -= killed) == 0)

		del_timer(&twdr->tw_timer);

	NET_ADD_STATS_BH(LINUX_MIB_TIMEWAITKILLED, killed);

	spin_unlock(&twdr->death_lock);

}



/* This is not only more efficient than what we used to do, it eliminates

 * a lot of code duplication between IPv4/IPv6 SYN recv processing. -DaveM

 *
@@ -933,4 +673,3 @@ EXPORT_SYMBOL(tcp_check_req); 
EXPORT_SYMBOL(tcp_child_process);

EXPORT_SYMBOL(tcp_create_openreq_child);

EXPORT_SYMBOL(tcp_timewait_state_process);
 
EXPORT_SYMBOL(inet_twsk_deschedule);