ipvs: Embed estimator object into stats object

There's no reason for dynamically allocating an estimator object for every
stats object. Directly embed an estimator object into every stats object and
switch to using the kernel-provided list implementation. This makes the code
much simpler and faster, as we do not need to traverse the list of all
estimators to find the one belonging to a stats object. There's no need to use
an rwlock, as we only have one reader. Also reorder the members of the
estimator structure slightly to avoid padding overhead. This can't be done
with the stats object as the members are currently copied to our user space
object via memcpy() and changing it would break ABI.

Signed-off-by: Sven Wegener <sven.wegener@stealer.net>
Acked-by: Simon Horman <horms@verge.net.au>

2 files changed, 39 insertions, 80 deletions

diff --git a/net/ipv4/ipvs/ip_vs_ctl.c b/net/ipv4/ipvs/ip_vs_ctl.c
index 999d884e8862ba..d651bce054931d 100644
--- a/net/ipv4/ipvs/ip_vs_ctl.c
+++ b/net/ipv4/ipvs/ip_vs_ctl.c
@@ -684,8 +684,8 @@ ip_vs_zero_stats(struct ip_vs_stats *stats)
 {
 	spin_lock_bh(&stats->lock);
 	memset(stats, 0, (char *)&stats->lock - (char *)stats);
-	spin_unlock_bh(&stats->lock);
 	ip_vs_zero_estimator(stats);
+	spin_unlock_bh(&stats->lock);
 }
 
 /*
diff --git a/net/ipv4/ipvs/ip_vs_est.c b/net/ipv4/ipvs/ip_vs_est.c
index 1d6e58e502fd8f..5a20f93bd7f940 100644
--- a/net/ipv4/ipvs/ip_vs_est.c
+++ b/net/ipv4/ipvs/ip_vs_est.c
@@ -17,6 +17,7 @@
 #include <linux/types.h>
 #include <linux/interrupt.h>
 #include <linux/sysctl.h>
+#include <linux/list.h>
 
 #include <net/ip_vs.h>
 
@@ -44,28 +45,11 @@
  */
 
 
-struct ip_vs_estimator
-{
-	struct ip_vs_estimator	*next;
-	struct ip_vs_stats	*stats;
-
-	u32			last_conns;
-	u32			last_inpkts;
-	u32			last_outpkts;
-	u64			last_inbytes;
-	u64			last_outbytes;
-
-	u32			cps;
-	u32			inpps;
-	u32			outpps;
-	u32			inbps;
-	u32			outbps;
-};
+static void estimation_timer(unsigned long arg);
 
-
-static struct ip_vs_estimator *est_list = NULL;
-static DEFINE_RWLOCK(est_lock);
-static struct timer_list est_timer;
+static LIST_HEAD(est_list);
+static DEFINE_SPINLOCK(est_lock);
+static DEFINE_TIMER(est_timer, estimation_timer, 0, 0);
 
 static void estimation_timer(unsigned long arg)
 {
@@ -76,9 +60,9 @@ static void estimation_timer(unsigned long arg)
 	u64 n_inbytes, n_outbytes;
 	u32 rate;
 
-	read_lock(&est_lock);
-	for (e = est_list; e; e = e->next) {
-		s = e->stats;
+	spin_lock(&est_lock);
+	list_for_each_entry(e, &est_list, list) {
+		s = container_of(e, struct ip_vs_stats, est);
 
 		spin_lock(&s->lock);
 		n_conns = s->conns;
@@ -114,19 +98,16 @@ static void estimation_timer(unsigned long arg)
 		s->outbps = (e->outbps+0xF)>>5;
 		spin_unlock(&s->lock);
 	}
-	read_unlock(&est_lock);
+	spin_unlock(&est_lock);
 	mod_timer(&est_timer, jiffies + 2*HZ);
 }
 
-int ip_vs_new_estimator(struct ip_vs_stats *stats)
+void ip_vs_new_estimator(struct ip_vs_stats *stats)
 {
-	struct ip_vs_estimator *est;
+	struct ip_vs_estimator *est = &stats->est;
 
-	est = kzalloc(sizeof(*est), GFP_KERNEL);
-	if (est == NULL)
-		return -ENOMEM;
+	INIT_LIST_HEAD(&est->list);
 
-	est->stats = stats;
 	est->last_conns = stats->conns;
 	est->cps = stats->cps<<10;
 
@@ -142,62 +123,40 @@ int ip_vs_new_estimator(struct ip_vs_stats *stats)
 	est->last_outbytes = stats->outbytes;
 	est->outbps = stats->outbps<<5;
 
-	write_lock_bh(&est_lock);
-	est->next = est_list;
-	if (est->next == NULL) {
-		setup_timer(&est_timer, estimation_timer, 0);
-		est_timer.expires = jiffies + 2*HZ;
-		add_timer(&est_timer);
-	}
-	est_list = est;
-	write_unlock_bh(&est_lock);
-	return 0;
+	spin_lock_bh(&est_lock);
+	if (list_empty(&est_list))
+		mod_timer(&est_timer, jiffies + 2 * HZ);
+	list_add(&est->list, &est_list);
+	spin_unlock_bh(&est_lock);
 }
 
 void ip_vs_kill_estimator(struct ip_vs_stats *stats)
 {
-	struct ip_vs_estimator *est, **pest;
-	int killed = 0;
-
-	write_lock_bh(&est_lock);
-	pest = &est_list;
-	while ((est=*pest) != NULL) {
-		if (est->stats != stats) {
-			pest = &est->next;
-			continue;
-		}
-		*pest = est->next;
-		kfree(est);
-		killed++;
-	}
-	while (killed && !est_list && try_to_del_timer_sync(&est_timer) < 0) {
-		write_unlock_bh(&est_lock);
+	struct ip_vs_estimator *est = &stats->est;
+
+	spin_lock_bh(&est_lock);
+	list_del(&est->list);
+	while (list_empty(&est_list) && try_to_del_timer_sync(&est_timer) < 0) {
+		spin_unlock_bh(&est_lock);
 		cpu_relax();
-		write_lock_bh(&est_lock);
+		spin_lock_bh(&est_lock);
 	}
-	write_unlock_bh(&est_lock);
+	spin_unlock_bh(&est_lock);
 }
 
 void ip_vs_zero_estimator(struct ip_vs_stats *stats)
 {
-	struct ip_vs_estimator *e;
-
-	write_lock_bh(&est_lock);
-	for (e = est_list; e; e = e->next) {
-		if (e->stats != stats)
-			continue;
-
-		/* set counters zero */
-		e->last_conns = 0;
-		e->last_inpkts = 0;
-		e->last_outpkts = 0;
-		e->last_inbytes = 0;
-		e->last_outbytes = 0;
-		e->cps = 0;
-		e->inpps = 0;
-		e->outpps = 0;
-		e->inbps = 0;
-		e->outbps = 0;
-	}
-	write_unlock_bh(&est_lock);
+	struct ip_vs_estimator *est = &stats->est;
+
+	/* set counters zero, caller must hold the stats->lock lock */
+	est->last_inbytes = 0;
+	est->last_outbytes = 0;
+	est->last_conns = 0;
+	est->last_inpkts = 0;
+	est->last_outpkts = 0;
+	est->cps = 0;
+	est->inpps = 0;
+	est->outpps = 0;
+	est->inbps = 0;
+	est->outbps = 0;
 }