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ipv6: cleanup after rt6_genid removal

PATCH In review Hannes Frederic Sowa 2 participants 7 messages Oct 6, 2014 – Oct 7, 2014

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Networking Network drivers IPv4/IPv6
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Hannes Frederic Sowa

author
#0 lore raw

v2 cover ipv6: cleanup after rt6_genid removal

Leftover patches after rt6_genid removal after 705f1c869d577c ("ipv6:
remove rt6i_genid").

Major two changes are:
* keep fib6_sernum per namespace to reduce number of flushes in case system has high number of namespaces
* make fn_sernum updates cheaper

v2: Incorporated feedback from Cong Wang, thanks a lot!

Hannes Frederic Sowa (5):
ipv6: minor fib6 cleanups like type safety, bool conversion, inline
removal
ipv6: make rt_sernum atomic and serial number fields ordinary ints
ipv6: only generate one new serial number per fib mutation
ipv6: make fib6 serial number per namespace
ipv6: don't walk node's leaf during serial number update

 include/net/ip6_fib.h    |  20 +++++--
 include/net/netns/ipv6.h |   2 +-
 net/ipv6/af_inet6.c      |   2 +-
 net/ipv6/ip6_fib.c       | 142 ++++++++++++++++++++++++-----------------------
 4 files changed, 91 insertions(+), 75 deletions(-)
Signature · 1 line
1.9.3
author
#1 lore raw

PATCH v2 1/5 ipv6: minor fib6 cleanups like type safety, bool conversion, inline removal

Also renamed struct fib6_walker_t to fib6_walker and enum fib_walk_state_t to fib6_walk_state as recommended by Cong Wang.

Cc Cong Wang <[email protected]>
Cc YOSHIFUJI Hideaki <[email protected]>
Cc Martin Lau <[email protected]>
Signed-off-by Hannes Frederic Sowa <[email protected]>
---
 include/net/ip6_fib.h | 18 ++++++++++---
 net/ipv6/ip6_fib.c    | 71 ++++++++++++++++++++++-----------------------------
 2 files changed, 45 insertions(+), 44 deletions(-)
include/net/ip6_fib.h +14 -4
index cf485f9..9221bf4 100644
@@ -202,15 +202,25 @@ static inline void ip6_rt_put(struct rt6_info *rt)
 	dst_release(&rt->dst);
 }
 
-struct fib6_walker_t {
+enum fib6_walk_state {
+#ifdef CONFIG_IPV6_SUBTREES
+	FWS_S,
+#endif
+	FWS_L,
+	FWS_R,
+	FWS_C,
+	FWS_U
+};
+
+struct fib6_walker {
 	struct list_head lh;
 	struct fib6_node *root, *node;
 	struct rt6_info *leaf;
-	unsigned char state;
-	unsigned char prune;
+	enum fib6_walk_state state;
+	bool prune;
 	unsigned int skip;
 	unsigned int count;
-	int (*func)(struct fib6_walker_t *);
+	int (*func)(struct fib6_walker *);
 	void *args;
 };
net/ipv6/ip6_fib.c +31 -40

228 lines not on this page · raw message

Signature · 1 line
1.9.3
author
#2 lore raw

PATCH v2 2/5 ipv6: make rt_sernum atomic and serial number fields ordinary ints

In reply to Hannes Frederic Sowa
Cc YOSHIFUJI Hideaki <[email protected]>
Cc Martin Lau <[email protected]>
Signed-off-by Hannes Frederic Sowa <[email protected]>
---
 include/net/ip6_fib.h |  2 +-
 net/ipv6/ip6_fib.c    | 23 +++++++++++++----------
 2 files changed, 14 insertions(+), 11 deletions(-)
include/net/ip6_fib.h +1 -1
index 9221bf4..8eea35d 100644
@@ -64,7 +64,7 @@ struct fib6_node {
 
 	__u16			fn_bit;		/* bit key */
 	__u16			fn_flags;
-	__u32			fn_sernum;
+	int			fn_sernum;
 	struct rt6_info		*rr_ptr;
 };
net/ipv6/ip6_fib.c +13 -10
index e8d7465..332f1e0 100644
@@ -74,7 +74,7 @@ static int fib6_walk_continue(struct fib6_walker *w);
  *	result of redirects, path MTU changes, etc.
  */
 
-static __u32 rt_sernum;
+static atomic_t rt_sernum = ATOMIC_INIT(1);
 
 static void fib6_gc_timer_cb(unsigned long arg);
 

@@ -95,12 +95,15 @@ static void fib6_walker_unlink(struct fib6_walker *w)
 	write_unlock_bh(&fib6_walker_lock);
 }
 
-static u32 fib6_new_sernum(void)
+static int fib6_new_sernum(void)
 {
-	u32 n = ++rt_sernum;
-	if ((__s32)n <= 0)
-		rt_sernum = n = 1;
-	return n;
+	int new, old;
+
+	do {
+		old = atomic_read(&rt_sernum);
+		new = old < INT_MAX ? old + 1 : 1;
+	} while (atomic_cmpxchg(&rt_sernum, old, new) != old);
+	return new;
 }
 
 /*

@@ -421,7 +424,7 @@ static struct fib6_node *fib6_add_1(struct fib6_node *root,
 	struct rt6key *key;
 	int	bit;
 	__be32	dir = 0;
-	__u32	sernum = fib6_new_sernum();
+	int	sernum = fib6_new_sernum();
 
 	RT6_TRACE("fib6_add_1\n");
 

@@ -1598,7 +1601,7 @@ static void fib6_prune_clones(struct net *net, struct fib6_node *fn)
 
 static int fib6_update_sernum(struct rt6_info *rt, void *arg)
 {
-	__u32 sernum = *(__u32 *)arg;
+	int sernum = *(int *)arg;
 
 	if (rt->rt6i_node &&
 	    rt->rt6i_node->fn_sernum != sernum)

@@ -1609,7 +1612,7 @@ static int fib6_update_sernum(struct rt6_info *rt, void *arg)
 
 static void fib6_flush_trees(struct net *net)
 {
-	__u32 new_sernum = fib6_new_sernum();
+	int new_sernum = fib6_new_sernum();
 
 	fib6_clean_all(net, fib6_update_sernum, &new_sernum);
 }

@@ -1822,7 +1825,7 @@ struct ipv6_route_iter {
 	struct fib6_walker w;
 	loff_t skip;
 	struct fib6_table *tbl;
-	__u32 sernum;
+	int sernum;
 };
 
 static int ipv6_route_seq_show(struct seq_file *seq, void *v)
Signature · 1 line
1.9.3
author
#3 lore raw

PATCH v2 3/5 ipv6: only generate one new serial number per fib mutation

In reply to Hannes Frederic Sowa
Cc YOSHIFUJI Hideaki <[email protected]>
Cc Martin Lau <[email protected]>
Signed-off-by Hannes Frederic Sowa <[email protected]>
---
 net/ipv6/ip6_fib.c | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)
net/ipv6/ip6_fib.c +6 -6
index 332f1e0..be9cb09 100644
@@ -417,14 +417,13 @@ out:
 static struct fib6_node *fib6_add_1(struct fib6_node *root,
 				     struct in6_addr *addr, int plen,
 				     int offset, int allow_create,
-				     int replace_required)
+				     int replace_required, int sernum)
 {
 	struct fib6_node *fn, *in, *ln;
 	struct fib6_node *pn = NULL;
 	struct rt6key *key;
 	int	bit;
 	__be32	dir = 0;
-	int	sernum = fib6_new_sernum();
 
 	RT6_TRACE("fib6_add_1\n");
 

@@ -842,6 +841,7 @@ int fib6_add(struct fib6_node *root, struct rt6_info *rt, struct nl_info *info,
 	int err = -ENOMEM;
 	int allow_create = 1;
 	int replace_required = 0;
+	int sernum = fib6_new_sernum();
 
 	if (info->nlh) {
 		if (!(info->nlh->nlmsg_flags & NLM_F_CREATE))

@@ -854,7 +854,7 @@ int fib6_add(struct fib6_node *root, struct rt6_info *rt, struct nl_info *info,
 
 	fn = fib6_add_1(root, &rt->rt6i_dst.addr, rt->rt6i_dst.plen,
 			offsetof(struct rt6_info, rt6i_dst), allow_create,
-			replace_required);
+			replace_required, sernum);
 	if (IS_ERR(fn)) {
 		err = PTR_ERR(fn);
 		fn = NULL;

@@ -888,14 +888,14 @@ int fib6_add(struct fib6_node *root, struct rt6_info *rt, struct nl_info *info,
 			sfn->leaf = info->nl_net->ipv6.ip6_null_entry;
 			atomic_inc(&info->nl_net->ipv6.ip6_null_entry->rt6i_ref);
 			sfn->fn_flags = RTN_ROOT;
-			sfn->fn_sernum = fib6_new_sernum();
+			sfn->fn_sernum = sernum;
 
 			/* Now add the first leaf node to new subtree */
 
 			sn = fib6_add_1(sfn, &rt->rt6i_src.addr,
 					rt->rt6i_src.plen,
 					offsetof(struct rt6_info, rt6i_src),
-					allow_create, replace_required);
+					allow_create, replace_required, sernum);
 
 			if (IS_ERR(sn)) {
 				/* If it is failed, discard just allocated

@@ -914,7 +914,7 @@ int fib6_add(struct fib6_node *root, struct rt6_info *rt, struct nl_info *info,
 			sn = fib6_add_1(fn->subtree, &rt->rt6i_src.addr,
 					rt->rt6i_src.plen,
 					offsetof(struct rt6_info, rt6i_src),
-					allow_create, replace_required);
+					allow_create, replace_required, sernum);
 
 			if (IS_ERR(sn)) {
 				err = PTR_ERR(sn);
Signature · 1 line
1.9.3
author
#4 lore raw

PATCH v2 4/5 ipv6: make fib6 serial number per namespace

In reply to Hannes Frederic Sowa

Try to reduce number of possible fn_sernum mutation by constraining them to their namespace.

Also remove rt_genid which I forgot to remove in 705f1c869d577c ("ipv6:
remove rt6i_genid").

Cc YOSHIFUJI Hideaki <[email protected]>
Cc Martin Lau <[email protected]>
Signed-off-by Hannes Frederic Sowa <[email protected]>
---
 include/net/netns/ipv6.h |  2 +-
 net/ipv6/af_inet6.c      |  2 +-
 net/ipv6/ip6_fib.c       | 13 ++++++-------
 3 files changed, 8 insertions(+), 9 deletions(-)
include/net/netns/ipv6.h +1 -1
index eade27a..69ae41f 100644
@@ -76,7 +76,7 @@ struct netns_ipv6 {
 #endif
 #endif
 	atomic_t		dev_addr_genid;
-	atomic_t		rt_genid;
+	atomic_t		fib6_sernum;
 };
 
 #if IS_ENABLED(CONFIG_NF_DEFRAG_IPV6)
net/ipv6/af_inet6.c +1 -1
index 34f726f..e8c4400 100644
@@ -766,7 +766,7 @@ static int __net_init inet6_net_init(struct net *net)
 	net->ipv6.sysctl.icmpv6_time = 1*HZ;
 	net->ipv6.sysctl.flowlabel_consistency = 1;
 	net->ipv6.sysctl.auto_flowlabels = 0;
-	atomic_set(&net->ipv6.rt_genid, 0);
+	atomic_set(&net->ipv6.fib6_sernum, 1);
 
 	err = ipv6_init_mibs(net);
 	if (err)
net/ipv6/ip6_fib.c +6 -7
index be9cb09..6f9beb1 100644
@@ -74,8 +74,6 @@ static int fib6_walk_continue(struct fib6_walker *w);
  *	result of redirects, path MTU changes, etc.
  */
 
-static atomic_t rt_sernum = ATOMIC_INIT(1);
-
 static void fib6_gc_timer_cb(unsigned long arg);
 
 static LIST_HEAD(fib6_walkers);

@@ -95,14 +93,15 @@ static void fib6_walker_unlink(struct fib6_walker *w)
 	write_unlock_bh(&fib6_walker_lock);
 }
 
-static int fib6_new_sernum(void)
+static int fib6_new_sernum(struct net *net)
 {
 	int new, old;
 
 	do {
-		old = atomic_read(&rt_sernum);
+		old = atomic_read(&net->ipv6.fib6_sernum);
 		new = old < INT_MAX ? old + 1 : 1;
-	} while (atomic_cmpxchg(&rt_sernum, old, new) != old);
+	} while (atomic_cmpxchg(&net->ipv6.fib6_sernum,
+				old, new) != old);
 	return new;
 }
 

@@ -841,7 +840,7 @@ int fib6_add(struct fib6_node *root, struct rt6_info *rt, struct nl_info *info,
 	int err = -ENOMEM;
 	int allow_create = 1;
 	int replace_required = 0;
-	int sernum = fib6_new_sernum();
+	int sernum = fib6_new_sernum(info->nl_net);
 
 	if (info->nlh) {
 		if (!(info->nlh->nlmsg_flags & NLM_F_CREATE))

@@ -1612,7 +1611,7 @@ static int fib6_update_sernum(struct rt6_info *rt, void *arg)
 
 static void fib6_flush_trees(struct net *net)
 {
-	int new_sernum = fib6_new_sernum();
+	int new_sernum = fib6_new_sernum(net);
 
 	fib6_clean_all(net, fib6_update_sernum, &new_sernum);
 }
Signature · 1 line
1.9.3
author
#5 lore raw

PATCH v2 5/5 ipv6: don't walk node's leaf during serial number update

In reply to Hannes Frederic Sowa
Cc YOSHIFUJI Hideaki <[email protected]>
Cc Martin Lau <[email protected]>
Signed-off-by Hannes Frederic Sowa <[email protected]>
---
 net/ipv6/ip6_fib.c | 47 ++++++++++++++++++++++++++++++-----------------
 1 file changed, 30 insertions(+), 17 deletions(-)
net/ipv6/ip6_fib.c +30 -17
index 6f9beb1..b2d1838 100644
@@ -50,6 +50,7 @@ struct fib6_cleaner {
 	struct fib6_walker w;
 	struct net *net;
 	int (*func)(struct rt6_info *, void *arg);
+	int sernum;
 	void *arg;
 };
 

@@ -105,6 +106,10 @@ static int fib6_new_sernum(struct net *net)
 	return new;
 }
 
+enum {
+	FIB6_NO_SERNUM_CHANGE = 0,
+};
+
 /*
  *	Auxiliary address test functions for the radix tree.
  *

@@ -1514,6 +1519,16 @@ static int fib6_clean_node(struct fib6_walker *w)
 		.nl_net = c->net,
 	};
 
+	if (c->sernum != FIB6_NO_SERNUM_CHANGE &&
+	    w->node->fn_sernum != c->sernum)
+		w->node->fn_sernum = c->sernum;
+
+	if (!c->func) {
+		WARN_ON_ONCE(c->sernum == FIB6_NO_SERNUM_CHANGE);
+		w->leaf = NULL;
+		return 0;
+	}
+
 	for (rt = w->leaf; rt; rt = rt->dst.rt6_next) {
 		res = c->func(rt, c->arg);
 		if (res < 0) {

@@ -1547,7 +1562,7 @@ static int fib6_clean_node(struct fib6_walker *w)
 
 static void fib6_clean_tree(struct net *net, struct fib6_node *root,
 			    int (*func)(struct rt6_info *, void *arg),
-			    bool prune, void *arg)
+			    bool prune, int sernum, void *arg)
 {
 	struct fib6_cleaner c;
 

@@ -1557,14 +1572,16 @@ static void fib6_clean_tree(struct net *net, struct fib6_node *root,
 	c.w.count = 0;
 	c.w.skip = 0;
 	c.func = func;
+	c.sernum = sernum;
 	c.arg = arg;
 	c.net = net;
 
 	fib6_walk(&c.w);
 }
 
-void fib6_clean_all(struct net *net, int (*func)(struct rt6_info *, void *arg),
-		    void *arg)
+static void __fib6_clean_all(struct net *net,
+			     int (*func)(struct rt6_info *, void *),
+			     int sernum, void *arg)
 {
 	struct fib6_table *table;
 	struct hlist_head *head;

@@ -1576,13 +1593,19 @@ void fib6_clean_all(struct net *net, int (*func)(struct rt6_info *, void *arg),
 		hlist_for_each_entry_rcu(table, head, tb6_hlist) {
 			write_lock_bh(&table->tb6_lock);
 			fib6_clean_tree(net, &table->tb6_root,
-					func, false, arg);
+					func, false, sernum, arg);
 			write_unlock_bh(&table->tb6_lock);
 		}
 	}
 	rcu_read_unlock();
 }
 
+void fib6_clean_all(struct net *net, int (*func)(struct rt6_info *, void *),
+		    void *arg)
+{
+	__fib6_clean_all(net, func, FIB6_NO_SERNUM_CHANGE, arg);
+}
+
 static int fib6_prune_clone(struct rt6_info *rt, void *arg)
 {
 	if (rt->rt6i_flags & RTF_CACHE) {

@@ -1595,25 +1618,15 @@ static int fib6_prune_clone(struct rt6_info *rt, void *arg)
 
 static void fib6_prune_clones(struct net *net, struct fib6_node *fn)
 {
-	fib6_clean_tree(net, fn, fib6_prune_clone, true, NULL);
-}
-
-static int fib6_update_sernum(struct rt6_info *rt, void *arg)
-{
-	int sernum = *(int *)arg;
-
-	if (rt->rt6i_node &&
-	    rt->rt6i_node->fn_sernum != sernum)
-		rt->rt6i_node->fn_sernum = sernum;
-
-	return 0;
+	fib6_clean_tree(net, fn, fib6_prune_clone, true,
+			FIB6_NO_SERNUM_CHANGE, NULL);
 }
 
 static void fib6_flush_trees(struct net *net)
 {
 	int new_sernum = fib6_new_sernum(net);
 
-	fib6_clean_all(net, fib6_update_sernum, &new_sernum);
+	__fib6_clean_all(net, NULL, new_sernum, NULL);
 }
 
 /*
Signature · 1 line
1.9.3
maintainer
#6 lore raw
In reply to Hannes Frederic Sowa

From: Hannes Frederic Sowa <[email protected]>
Date: Mon, 6 Oct 2014 19:58:33 +0200

Quoted 9 lines

Leftover patches after rt6_genid removal after 705f1c869d577c ("ipv6:
remove rt6i_genid").

Major two changes are:
* keep fib6_sernum per namespace to reduce number of flushes in case system has high number of namespaces
* make fn_sernum updates cheaper

v2: Incorporated feedback from Cong Wang, thanks a lot!

Series applied, thanks.