[PATCH 2.4.22-pre1][NET] timer cleanups

[PATCH 2.4.22-pre1][NET] timer cleanups

[Vinay K Nallamothu]

Hi,

This patch does the following timer code cleanup:

1. Change del_timer/add_timer to mod_timer
2. Use static timer initialisation wherever applicable


 drivers/net/hamradio/6pack.c            |   38 ++++++++++----------------------
 drivers/net/wan/sdla_ppp.c              |    4 ---
 net/atm/lec.c                           |    5 ----
 net/ipv4/netfilter/ip_conntrack_core.c  |   12 ++++------
 net/ipv4/netfilter/ip_fw_compat_redir.c |   12 +++-------
 net/ipv6/ip6_flowlabel.c                |   12 ++++------
 net/netrom/nr_loopback.c                |   19 +++-------------
 net/rose/rose_loopback.c                |   20 +++-------------
 net/sched/sch_cbq.c                     |    7 ++---
 net/sched/sch_sfq.c                     |   11 ++++-----
 net/wanrouter/af_wanpipe.c              |    7 +----
 11 files changed, 46 insertions(+), 101 deletions(-)

diff -urN linux-2.4.22/drivers/net/hamradio/6pack.c linux-2.4.22-nvk/drivers/net/hamradio/6pack.c
--- linux-2.4.22/drivers/net/hamradio/6pack.c	2003-06-14 10:03:18.000000000 +0530
+++ linux-2.4.22-nvk/drivers/net/hamradio/6pack.c	2003-08-30 15:26:04.000000000 +0530
@@ -140,7 +140,7 @@
 MODULE_PARM(sixpack_maxdev, "i");
 MODULE_PARM_DESC(sixpack_maxdev, "number of 6PACK devices");
 
-static void sp_start_tx_timer(struct sixpack *);
+static inline void sp_start_tx_timer(struct sixpack *);
 static void sp_xmit_on_air(unsigned long);
 static void resync_tnc(unsigned long);
 static void sixpack_decode(struct sixpack *, unsigned char[], int);
@@ -480,7 +480,12 @@
 	netif_start_queue(dev);
 
 	init_timer(&sp->tx_t);
+	sp->tx_t.data = (unsigned long) sp;
+	sp->tx_t.function = sp_xmit_on_air;
+
 	init_timer(&sp->resync_t);
+	sp->resync_t.data = (unsigned long) sp;
+	sp->resync_t.function = resync_tnc;
 	return 0;
 }
 
@@ -803,15 +808,10 @@
 
 
 /* ----> 6pack timer interrupt handler and friends. <---- */
-static void sp_start_tx_timer(struct sixpack *sp)
+static inline void sp_start_tx_timer(struct sixpack *sp)
 {
 	int when = sp->slottime;
-
-	del_timer(&sp->tx_t);
-	sp->tx_t.data = (unsigned long) sp;
-	sp->tx_t.function = sp_xmit_on_air;
-	sp->tx_t.expires = jiffies + ((when+1)*HZ)/100;
-	add_timer(&sp->tx_t);
+	mod_timer(&sp->tx_t, jiffies + ((when+1)*HZ)/100);
 }
 
 
@@ -883,12 +883,7 @@
 
 	sp->tty->driver.write(sp->tty, 0, &inbyte, 1);
 
-	del_timer(&sp->resync_t);
-	sp->resync_t.data = (unsigned long) sp;
-	sp->resync_t.function = resync_tnc;
-	sp->resync_t.expires = jiffies + SIXP_RESYNC_TIMEOUT;
-	add_timer(&sp->resync_t);
-
+	mod_timer(&sp->resync_t.expires, jiffies + SIXP_RESYNC_TIMEOUT);
 	return 0;
 }
 
@@ -940,13 +935,8 @@
         /* if the state byte has been received, the TNC is present,
            so the resync timer can be reset. */
 
-	if (sp->tnc_ok == 1) {
-		del_timer(&sp->resync_t);
-		sp->resync_t.data = (unsigned long) sp;
-		sp->resync_t.function = resync_tnc;
-		sp->resync_t.expires = jiffies + SIXP_INIT_RESYNC_TIMEOUT;
-		add_timer(&sp->resync_t);
-	}
+	if (sp->tnc_ok == 1)
+		mod_timer(&sp->resync_t, jiffies + SIXP_INIT_RESYNC_TIMEOUT);
 
 	sp->status1 = cmd & SIXP_PRIO_DATA_MASK;
 }
@@ -982,11 +972,7 @@
 
 	/* Start resync timer again -- the TNC might be still absent */
 
-	del_timer(&sp->resync_t);
-	sp->resync_t.data = (unsigned long) sp;
-	sp->resync_t.function = resync_tnc;
-	sp->resync_t.expires = jiffies + SIXP_RESYNC_TIMEOUT;
-	add_timer(&sp->resync_t);
+	mod_timer(&sp->resync_t, jiffies + SIXP_RESYNC_TIMEOUT);
 }
 
 
diff -urN linux-2.4.22/drivers/net/wan/sdla_ppp.c linux-2.4.22-nvk/drivers/net/wan/sdla_ppp.c
--- linux-2.4.22/drivers/net/wan/sdla_ppp.c	2003-06-14 10:03:17.000000000 +0530
+++ linux-2.4.22-nvk/drivers/net/wan/sdla_ppp.c	2003-08-26 11:12:56.000000000 +0530
@@ -841,9 +841,7 @@
 	/* Start the PPP configuration after 1sec delay.
 	 * This will give the interface initilization time
 	 * to finish its configuration */
-	del_timer(&ppp_priv_area->poll_delay_timer);
-	ppp_priv_area->poll_delay_timer.expires = jiffies+HZ;
-	add_timer(&ppp_priv_area->poll_delay_timer);
+	mod_timer(&ppp_priv_area->poll_delay_timer, jiffies + HZ);
 	return 0;
 }
 
diff -urN linux-2.4.22/net/atm/lec.c linux-2.4.22-nvk/net/atm/lec.c
--- linux-2.4.22/net/atm/lec.c	2003-08-26 10:08:26.000000000 +0530
+++ linux-2.4.22-nvk/net/atm/lec.c	2003-08-30 16:37:57.000000000 +0530
@@ -1489,8 +1489,6 @@
 
         entry = (struct lec_arp_table *)data;
 
-        del_timer(&entry->timer);
-
         DPRINTK("lec_arp_expire_arp\n");
         if (entry->status == ESI_ARP_PENDING) {
                 if (entry->no_tries <= entry->priv->max_retry_count) {
@@ -1500,8 +1498,7 @@
                                 send_to_lecd(entry->priv, l_arp_xmt, entry->mac_addr, NULL, NULL);
                         entry->no_tries++;
                 }
-                entry->timer.expires = jiffies + (1*HZ);
-                add_timer(&entry->timer);
+                mod_timer(&entry->timer, jiffies + 1 * HZ);
         }
 }
 
diff -urN linux-2.4.22/net/ipv4/netfilter/ip_conntrack_core.c linux-2.4.22-nvk/net/ipv4/netfilter/ip_conntrack_core.c
--- linux-2.4.22/net/ipv4/netfilter/ip_conntrack_core.c	2003-08-26 10:08:30.000000000 +0530
+++ linux-2.4.22-nvk/net/ipv4/netfilter/ip_conntrack_core.c	2003-08-26 21:54:45.000000000 +0530
@@ -954,13 +954,12 @@
 		   the data filled out by the helper over the old one */
 		DEBUGP("expect_related: resent packet\n");
 		if (related_to->helper->timeout) {
-			if (!del_timer(&old->timeout)) {
+			if (!timer_pending(&old->timeout)) {
 				/* expectation is dying. Fall through */
 				old = NULL;
 			} else {
-				old->timeout.expires = jiffies + 
-					related_to->helper->timeout * HZ;
-				add_timer(&old->timeout);
+				mod_timer(&old->timeout, jiffies + 
+					related_to->helper->timeout * HZ);
 			}
 		}
 
@@ -1182,9 +1181,8 @@
 		ct->timeout.expires = extra_jiffies;
 	else {
 		/* Need del_timer for race avoidance (may already be dying). */
-		if (del_timer(&ct->timeout)) {
-			ct->timeout.expires = jiffies + extra_jiffies;
-			add_timer(&ct->timeout);
+		if (timer_pending(&ct->timeout)) {
+			mod_timer(&ct->timeout, extra_jiffies);
 		}
 	}
 	WRITE_UNLOCK(&ip_conntrack_lock);
diff -urN linux-2.4.22/net/ipv4/netfilter/ip_fw_compat_redir.c linux-2.4.22-nvk/net/ipv4/netfilter/ip_fw_compat_redir.c
--- linux-2.4.22/net/ipv4/netfilter/ip_fw_compat_redir.c	2003-06-14 10:03:12.000000000 +0530
+++ linux-2.4.22-nvk/net/ipv4/netfilter/ip_fw_compat_redir.c	2003-08-30 14:41:23.000000000 +0530
@@ -270,10 +270,8 @@
 	if (redir) {
 		DEBUGP("Doing tcp redirect again.\n");
 		do_tcp_redir(skb, redir);
-		if (del_timer(&redir->destroyme)) {
-			redir->destroyme.expires = jiffies + REDIR_TIMEOUT;
-			add_timer(&redir->destroyme);
-		}
+		if (timer_pending(&redir->destroyme))
+			mod_timer(&redir->destroyme, jiffies + REDIR_TIMEOUT);
 	}
 	UNLOCK_BH(&redir_lock);
 }
@@ -298,10 +296,8 @@
 	if (redir) {
 		DEBUGP("Doing tcp unredirect.\n");
 		do_tcp_unredir(skb, redir);
-		if (del_timer(&redir->destroyme)) {
-			redir->destroyme.expires = jiffies + REDIR_TIMEOUT;
-			add_timer(&redir->destroyme);
-		}
+		if (timer_pending(&redir->destroyme))
+			mod_timer(&redir->destroyme, jiffies + REDIR_TIMEOUT);
 	}
 	UNLOCK_BH(&redir_lock);
 }
diff -urN linux-2.4.22/net/ipv6/ip6_flowlabel.c linux-2.4.22-nvk/net/ipv6/ip6_flowlabel.c
--- linux-2.4.22/net/ipv6/ip6_flowlabel.c	2003-06-14 10:03:12.000000000 +0530
+++ linux-2.4.22-nvk/net/ipv6/ip6_flowlabel.c	2003-08-26 21:10:46.000000000 +0530
@@ -48,7 +48,8 @@
 static atomic_t fl_size = ATOMIC_INIT(0);
 static struct ip6_flowlabel *fl_ht[FL_HASH_MASK+1];
 
-static struct timer_list ip6_fl_gc_timer;
+static void ip6_fl_gc(unsigned long dummy);
+static struct timer_list ip6_fl_gc_timer = TIMER_INITIALIZER(ip6_fl_gc, 0, 0);
 
 /* FL hash table lock: it protects only of GC */
 
@@ -103,10 +104,9 @@
 			fl->opt = NULL;
 			kfree(opt);
 		}
-		if (!del_timer(&ip6_fl_gc_timer) ||
-		    (long)(ip6_fl_gc_timer.expires - ttd) > 0)
-			ip6_fl_gc_timer.expires = ttd;
-		add_timer(&ip6_fl_gc_timer);
+		if (!timer_pending(&ip6_fl_gc_timer) ||
+		    time_after(ip6_fl_gc_timer.expires, ttd))
+			mod_timer(&ip6_fl_gc_timer, ttd);
 	}
 }
 
@@ -609,8 +609,6 @@
 
 void ip6_flowlabel_init()
 {
-	init_timer(&ip6_fl_gc_timer);
-	ip6_fl_gc_timer.function = ip6_fl_gc;
 #ifdef CONFIG_PROC_FS
 	create_proc_read_entry("net/ip6_flowlabel", 0, 0, ip6_fl_read_proc, NULL);
 #endif
diff -urN linux-2.4.22/net/netrom/nr_loopback.c linux-2.4.22-nvk/net/netrom/nr_loopback.c
--- linux-2.4.22/net/netrom/nr_loopback.c	2003-06-14 10:03:12.000000000 +0530
+++ linux-2.4.22-nvk/net/netrom/nr_loopback.c	2003-08-30 16:21:47.000000000 +0530
@@ -23,8 +23,10 @@
 #include <net/netrom.h>
 #include <linux/init.h>
 
+static void nr_loopback_timer(unsigned long);
+
 static struct sk_buff_head loopback_queue;
-static struct timer_list loopback_timer;
+static struct timer_list loopback_timer = TIMER_INITIALIZER(nr_loopback_timer, 0, 0);
 
 static void nr_set_loopback_timer(void);
 
@@ -51,26 +53,13 @@
 		skb_queue_tail(&loopback_queue, skbn);
 
 		if (!nr_loopback_running())
-			nr_set_loopback_timer();
+			mod_timer(&loopback_timer, jiffies + 10);
 	}
 
 	kfree_skb(skb);
 	return 1;
 }
 
-static void nr_loopback_timer(unsigned long);
-
-static void nr_set_loopback_timer(void)
-{
-	del_timer(&loopback_timer);
-
-	loopback_timer.data     = 0;
-	loopback_timer.function = &nr_loopback_timer;
-	loopback_timer.expires  = jiffies + 10;
-
-	add_timer(&loopback_timer);
-}
-
 static void nr_loopback_timer(unsigned long param)
 {
 	struct sk_buff *skb;
diff -urN linux-2.4.22/net/rose/rose_loopback.c linux-2.4.22-nvk/net/rose/rose_loopback.c
--- linux-2.4.22/net/rose/rose_loopback.c	2003-06-14 10:03:13.000000000 +0530
+++ linux-2.4.22-nvk/net/rose/rose_loopback.c	2003-08-30 15:41:40.000000000 +0530
@@ -22,10 +22,10 @@
 #include <net/rose.h>
 #include <linux/init.h>
 
-static struct sk_buff_head loopback_queue;
-static struct timer_list loopback_timer;
+static void rose_loopback_timer(unsigned long);
 
-static void rose_set_loopback_timer(void);
+static struct sk_buff_head loopback_queue;
+static struct timer_list loopback_timer = TIMER_INITIALIZER(rose_loopback_timer, 0, 0);
 
 void rose_loopback_init(void)
 {
@@ -51,24 +51,12 @@
 		skb_queue_tail(&loopback_queue, skbn);
 
 		if (!rose_loopback_running())
-			rose_set_loopback_timer();
+			mod_timer(&loopback_timer, jiffies + 10);
 	}
 
 	return 1;
 }
 
-static void rose_loopback_timer(unsigned long);
-
-static void rose_set_loopback_timer(void)
-{
-	del_timer(&loopback_timer);
-
-	loopback_timer.data     = 0;
-	loopback_timer.function = &rose_loopback_timer;
-	loopback_timer.expires  = jiffies + 10;
-
-	add_timer(&loopback_timer);
-}
 
 static void rose_loopback_timer(unsigned long param)
 {
diff -urN linux-2.4.22/net/sched/sch_cbq.c linux-2.4.22-nvk/net/sched/sch_cbq.c
--- linux-2.4.22/net/sched/sch_cbq.c	2003-08-26 10:08:36.000000000 +0530
+++ linux-2.4.22-nvk/net/sched/sch_cbq.c	2003-08-30 14:56:04.000000000 +0530
@@ -554,10 +554,9 @@
 			cl->penalized = sched;
 			cl->cpriority = TC_CBQ_MAXPRIO;
 			q->pmask |= (1<<TC_CBQ_MAXPRIO);
-			if (del_timer(&q->delay_timer) &&
-			    (long)(q->delay_timer.expires - sched) > 0)
-				q->delay_timer.expires = sched;
-			add_timer(&q->delay_timer);
+			if (timer_pending(&q->delay_timer) &&
+			    time_after(q->delay_timer.expires, sched))
+				mod_timer(&q->delay_timer, sched);
 			cl->delayed = 1;
 			cl->xstats.overactions++;
 			return;
diff -urN linux-2.4.22/net/sched/sch_sfq.c linux-2.4.22-nvk/net/sched/sch_sfq.c
--- linux-2.4.22/net/sched/sch_sfq.c	2003-08-26 10:08:36.000000000 +0530
+++ linux-2.4.22-nvk/net/sched/sch_sfq.c	2003-08-30 14:51:57.000000000 +0530
@@ -371,7 +371,6 @@
 	struct sfq_sched_data *q = (struct sfq_sched_data *)sch->data;
 
 	q->perturbation = net_random()&0x1F;
-	q->perturb_timer.expires = jiffies + q->perturb_period;
 
 	if (q->perturb_period) {
 		q->perturb_timer.expires = jiffies + q->perturb_period;
@@ -396,11 +395,11 @@
 	while (sch->q.qlen >= q->limit-1)
 		sfq_drop(sch);
 
-	del_timer(&q->perturb_timer);
-	if (q->perturb_period) {
-		q->perturb_timer.expires = jiffies + q->perturb_period;
-		add_timer(&q->perturb_timer);
-	}
+	if (q->perturb_period)
+		mod_timer(&q->perturb_timer, jiffies + q->perturb_period);
+	else
+		del_timer(&q->perturb_timer);
+
 	sch_tree_unlock(sch);
 	return 0;
 }
diff -urN linux-2.4.22/net/wanrouter/af_wanpipe.c linux-2.4.22-nvk/net/wanrouter/af_wanpipe.c
--- linux-2.4.22/net/wanrouter/af_wanpipe.c	2003-06-14 10:03:13.000000000 +0530
+++ linux-2.4.22-nvk/net/wanrouter/af_wanpipe.c	2003-08-26 11:21:31.000000000 +0530
@@ -649,11 +649,8 @@
 	skb_queue_tail(&sk->write_queue,skb);
 	atomic_inc(&sk->protinfo.af_wanpipe->packet_sent);
 
-	if (!(test_and_set_bit(0,&sk->protinfo.af_wanpipe->timer))){
-		del_timer(&sk->protinfo.af_wanpipe->tx_timer);
-		sk->protinfo.af_wanpipe->tx_timer.expires=jiffies+1;
-		add_timer(&sk->protinfo.af_wanpipe->tx_timer);
-	}	
+	if (!test_and_set_bit(0,&sk->protinfo.af_wanpipe->timer))
+		mod_timer(&sk->protinfo.af_wanpipe->tx_timer, jiffies + 1);
 	
 	return(len);
 

Re: [PATCH 2.4.22-pre1][NET] timer cleanups

[David S. Miller]

On Sat, 30 Aug 2003 21:11:37 +0530
Vinay K Nallamothu <vinay-rc@naturesoft.net> wrote:

> This patch does the following timer code cleanup:
> 
> 1. Change del_timer/add_timer to mod_timer
> 2. Use static timer initialisation wherever applicable

I'm not accepting this.  In particular, the ip6_flowlabel.c
change is a bad idea because the code remains racey.  Someone
submitted a similar move to mod_timer() for ip6_flowlabel
earlier this week so see my comments there about what needs
to occur to fix the code properly.

Just blindly doing these kinds of conversions to mod_timer()
is foolhardy.  You need to apply some brains to it to make
sure you really are getting rid of whatever potential races
exist in the code.  And in the ip6_flowlabel.c case things are
as buggy as they were before.

Re: [PATCH 2.4.22-pre1][NET] timer cleanups

[Vinay K Nallamothu]

Hi Dave,

On Sun, 2003-08-31 at 09:03, David S. Miller wrote:
> On Sat, 30 Aug 2003 21:11:37 +0530
> Vinay K Nallamothu <vinay-rc@naturesoft.net> wrote:
> 
> > This patch does the following timer code cleanup:
> > 
> > 1. Change del_timer/add_timer to mod_timer
> > 2. Use static timer initialisation wherever applicable
> 
> I'm not accepting this.  In particular, the ip6_flowlabel.c
> change is a bad idea because the code remains racey.


>   Someone
> submitted a similar move to mod_timer() for ip6_flowlabel
That too was submitted by me. Unfortunately I never got to see your
mail. No excuses though.


> 
> Just blindly doing these kinds of conversions to mod_timer()
> is foolhardy.  You need to apply some brains to it to make
> sure you really are getting rid of whatever potential races
> exist in the code. 
You are correct. While I tried to make sure that new bugs are not
introduced, I haven't paid attention to the existing ones.

>  And in the ip6_flowlabel.c case things are
> as buggy as they were before.

Please find the updated patch below and let me know if it's ok.

Thanks
Vinay

ip6_flowlabel.c: 
1. Use static timer initializer
2. Use timer macros to handle jiffie wrap in comparisions
3. Convert del_timer/add_timer to mod_timer

ip6_flowlabel.c |   30 ++++++++++++++++--------------
 1 files changed, 16 insertions(+), 14 deletions(-)

diff -urN linux-2.4.22/net/ipv6/ip6_flowlabel.c	linux-2.4.22-nvk/net/ipv6/ip6_flowlabel.c
--- linux-2.4.22/net/ipv6/ip6_flowlabel.c	2003-06-14 10:03:12.000000000 +0530
+++ linux-2.4.22-nvk/net/ipv6/ip6_flowlabel.c	2003-09-01 16:47:03.000000000 +0530
@@ -48,7 +48,8 @@
 static atomic_t fl_size = ATOMIC_INIT(0);
 static struct ip6_flowlabel *fl_ht[FL_HASH_MASK+1];
 
-static struct timer_list ip6_fl_gc_timer;
+static void ip6_fl_gc(unsigned long dummy);
+static struct timer_list ip6_fl_gc_timer = TIMER_INITIALIZER(ip6_fl_gc, 0, 0);
 
 /* FL hash table lock: it protects only of GC */
 
@@ -92,10 +93,12 @@
 
 static void fl_release(struct ip6_flowlabel *fl)
 {
+	write_lock_bh(&ip6_fl_lock);
+
 	fl->lastuse = jiffies;
 	if (atomic_dec_and_test(&fl->users)) {
 		unsigned long ttd = fl->lastuse + fl->linger;
-		if ((long)(ttd - fl->expires) > 0)
+		if (time_after(ttd, fl->expires))
 			fl->expires = ttd;
 		ttd = fl->expires;
 		if (fl->opt && fl->share == IPV6_FL_S_EXCL) {
@@ -103,11 +106,12 @@
 			fl->opt = NULL;
 			kfree(opt);
 		}
-		if (!del_timer(&ip6_fl_gc_timer) ||
-		    (long)(ip6_fl_gc_timer.expires - ttd) > 0)
-			ip6_fl_gc_timer.expires = ttd;
-		add_timer(&ip6_fl_gc_timer);
+		if (!timer_pending(&ip6_fl_gc_timer) ||
+		    time_after(ip6_fl_gc_timer.expires, ttd))
+			mod_timer(&ip6_fl_gc_timer, ttd);
 	}
+
+	write_unlock_bh(&ip6_fl_lock);
 }
 
 static void ip6_fl_gc(unsigned long dummy)
@@ -124,16 +128,16 @@
 		while ((fl=*flp) != NULL) {
 			if (atomic_read(&fl->users) == 0) {
 				unsigned long ttd = fl->lastuse + fl->linger;
-				if ((long)(ttd - fl->expires) > 0)
+				if (time_after(ttd, fl->expires))
 					fl->expires = ttd;
 				ttd = fl->expires;
-				if ((long)(now - ttd) >= 0) {
+				if (time_after_eq(now, ttd)) {
 					*flp = fl->next;
 					fl_free(fl);
 					atomic_dec(&fl_size);
 					continue;
 				}
-				if (!sched || (long)(ttd - sched) < 0)
+				if (!sched || time_before(ttd, sched))
 					sched = ttd;
 			}
 			flp = &fl->next;
@@ -262,11 +266,11 @@
 	if (!expires)
 		return -EPERM;
 	fl->lastuse = jiffies;
-	if (fl->linger < linger)
+	if (time_before(fl->linger, linger))
 		fl->linger = linger;
-	if (expires < fl->linger)
+	if (time_before(expires, fl->linger))
 		expires = fl->linger;
-	if ((long)(fl->expires - (fl->lastuse+expires)) < 0)
+	if (time_before(fl->expires, fl->lastuse + expires))
 		fl->expires = fl->lastuse + expires;
 	return 0;
 }
@@ -609,8 +613,6 @@
 
 void ip6_flowlabel_init()
 {
-	init_timer(&ip6_fl_gc_timer);
-	ip6_fl_gc_timer.function = ip6_fl_gc;
 #ifdef CONFIG_PROC_FS
 	create_proc_read_entry("net/ip6_flowlabel", 0, 0, ip6_fl_read_proc, NULL);
 #endif

Re: [PATCH 2.4.22-pre1][NET] timer cleanups

[David S. Miller]

On Mon, 01 Sep 2003 19:30:51 +0530
Vinay K Nallamothu <vinay-rc@naturesoft.net> wrote:

> >  And in the ip6_flowlabel.c case things are
> > as buggy as they were before.
> 
> Please find the updated patch below and let me know if it's ok.

Looks great, patch applied.