ipv6: Remove BACKTRACK macro

It is the prep work to reduce the number of calls to fib6_lookup(). The BACKTRACK macro could be hard-to-read and error-prone due to its side effects (mainly goto). This patch is to: 1. Replace BACKTRACK macro with a function (fib6_backtrack) with the following return values: * If it is backtrack-able, returns next fn for retry. * If it reaches the root, returns NULL. 2. The caller needs to decide if a backtrack is needed (by testing rt == net->ipv6.ip6_null_entry). 3. Rename the goto labels in ip6_pol_route() to make the next few patches easier to read. Cc: David Miller <davem@davemloft.net> Cc: Hannes Frederic Sowa <hannes@stressinduktion.org> Signed-off-by: Martin KaFai Lau <kafai@fb.com> Signed-off-by: David S. Miller <davem@davemloft.net>
author: Martin KaFai Lau <kafai@fb.com> 2014-10-20 16:42:43 -0400
committer: David S. Miller <davem@davemloft.net> 2014-10-24 00:14:39 -0400
commit: a3c00e46efdb4009369971c97203ea67f7630fe4 (patch)
tree: 98789f21ff6f3fd596ec49933fc69d5d0979be44 /net/ipv6
parent: 105970f6087ae240b00deaff85773ed9bf381145 (diff)
1 files changed, 40 insertions, 30 deletions
diff --git a/net/ipv6/route.c b/net/ipv6/route.c
index a318dd89b6d9..f1ab2f4f4529 100644
--- a/net/ipv6/route.c
+++ b/net/ipv6/route.c
@@ -772,23 +772,22 @@ int rt6_route_rcv(struct net_device *dev, u8 *opt, int len,
 }
 #endif
-#define BACKTRACK(__net, saddr)                 \
+static struct fib6_node* fib6_backtrack(struct fib6_node *fn,
-do { \
+                                        struct in6_addr *saddr)
-        if (rt == __net->ipv6.ip6_null_entry) { \
+{
-                struct fib6_node *pn; \
+        struct fib6_node *pn;
-                while (1) { \
+        while (1) {
-                        if (fn->fn_flags & RTN_TL_ROOT) \
+                if (fn->fn_flags & RTN_TL_ROOT)
-                                goto out; \
+                        return NULL;
-                        pn = fn->parent; \
+                pn = fn->parent;
-                        if (FIB6_SUBTREE(pn) && FIB6_SUBTREE(pn) != fn) \
+                if (FIB6_SUBTREE(pn) && FIB6_SUBTREE(pn) != fn)
-                                fn = fib6_lookup(FIB6_SUBTREE(pn), NULL, saddr); \
+                        fn = fib6_lookup(FIB6_SUBTREE(pn), NULL, saddr);
-                        else \
+                else
-                                fn = pn; \
+                        fn = pn;
-                        if (fn->fn_flags & RTN_RTINFO) \
+                if (fn->fn_flags & RTN_RTINFO)
-                                goto restart; \
+                        return fn;
-                } \
+        }
-        } \
+}
-} while (0)
 static struct rt6_info *ip6_pol_route_lookup(struct net *net,
                                             struct fib6_table *table,
@@ -804,8 +803,11 @@ restart:
        rt = rt6_device_match(net, rt, &fl6->saddr, fl6->flowi6_oif, flags);
        if (rt->rt6i_nsiblings && fl6->flowi6_oif == 0)
                rt = rt6_multipath_select(rt, fl6, fl6->flowi6_oif, flags);
-        BACKTRACK(net, &fl6->saddr);
+        if (rt == net->ipv6.ip6_null_entry) {
-out:
+                fn = fib6_backtrack(fn, &fl6->saddr);
+                if (fn)
+                        goto restart;
+        }
        dst_use(&rt->dst, jiffies);
        read_unlock_bh(&table->tb6_lock);
        return rt;
@@ -924,19 +926,25 @@ static struct rt6_info *ip6_pol_route(struct net *net, struct fib6_table *table,
        strict |= flags & RT6_LOOKUP_F_IFACE;
-relookup:
+redo_fib6_lookup_lock:
        read_lock_bh(&table->tb6_lock);
-restart_2:
+redo_fib6_lookup:
        fn = fib6_lookup(&table->tb6_root, &fl6->daddr, &fl6->saddr);
-restart:
+redo_rt6_select:
        rt = rt6_select(fn, oif, strict | reachable);
        if (rt->rt6i_nsiblings)
                rt = rt6_multipath_select(rt, fl6, oif, strict | reachable);
-        BACKTRACK(net, &fl6->saddr);
+        if (rt == net->ipv6.ip6_null_entry) {
-        if (rt == net->ipv6.ip6_null_entry ||
+                fn = fib6_backtrack(fn, &fl6->saddr);
-            rt->rt6i_flags & RTF_CACHE)
+                if (fn)
+                        goto redo_rt6_select;
+                else
+                        goto out;
+        }
+        if (rt->rt6i_flags & RTF_CACHE)
                goto out;
        dst_hold(&rt->dst);
@@ -967,12 +975,12 @@ restart:
         * released someone could insert this route.  Relookup.
         */
        ip6_rt_put(rt);
-        goto relookup;
+        goto redo_fib6_lookup_lock;
 out:
        if (reachable) {
                reachable = 0;
-                goto restart_2;
+                goto redo_fib6_lookup;
        }
        dst_hold(&rt->dst);
        read_unlock_bh(&table->tb6_lock);
@@ -1235,10 +1243,12 @@ restart:
                rt = net->ipv6.ip6_null_entry;
        else if (rt->dst.error) {
                rt = net->ipv6.ip6_null_entry;
-                goto out;
+        } else if (rt == net->ipv6.ip6_null_entry) {
+                fn = fib6_backtrack(fn, &fl6->saddr);
+                if (fn)
+                        goto restart;
        }
-        BACKTRACK(net, &fl6->saddr);
-out:
        dst_hold(&rt->dst);
        read_unlock_bh(&table->tb6_lock);
author	Martin KaFai Lau <kafai@fb.com>	2014-10-20 16:42:43 -0400
committer	David S. Miller <davem@davemloft.net>	2014-10-24 00:14:39 -0400
commit	a3c00e46efdb4009369971c97203ea67f7630fe4 (patch)
tree	98789f21ff6f3fd596ec49933fc69d5d0979be44 /net/ipv6
parent	105970f6087ae240b00deaff85773ed9bf381145 (diff)

diff --git a/net/ipv6/route.c b/net/ipv6/route.c index a318dd89b6d9..f1ab2f4f4529 100644 --- a/net/ipv6/route.c +++ b/net/ipv6/route.c
@@ -772,23 +772,22 @@ int rt6_route_rcv(struct net_device dev, u8 opt, int len,
772	}	772	}
773	#endif	773	#endif
774		774
775	#define BACKTRACK(__net, saddr) \	775	static struct fib6_node* fib6_backtrack(struct fib6_node *fn,
776	do { \	776	struct in6_addr *saddr)
777	if (rt == __net->ipv6.ip6_null_entry) { \	777	{
778	struct fib6_node *pn; \	778	struct fib6_node *pn;
779	while (1) { \	779	while (1) {
780	if (fn->fn_flags & RTN_TL_ROOT) \	780	if (fn->fn_flags & RTN_TL_ROOT)
781	goto out; \	781	return NULL;
782	pn = fn->parent; \	782	pn = fn->parent;
783	if (FIB6_SUBTREE(pn) && FIB6_SUBTREE(pn) != fn) \	783	if (FIB6_SUBTREE(pn) && FIB6_SUBTREE(pn) != fn)
784	fn = fib6_lookup(FIB6_SUBTREE(pn), NULL, saddr); \	784	fn = fib6_lookup(FIB6_SUBTREE(pn), NULL, saddr);
785	else \	785	else
786	fn = pn; \	786	fn = pn;
787	if (fn->fn_flags & RTN_RTINFO) \	787	if (fn->fn_flags & RTN_RTINFO)
788	goto restart; \	788	return fn;
789	} \	789	}
790	} \	790	}
791	} while (0)
792		791
793	static struct rt6_info ip6_pol_route_lookup(struct net net,	792	static struct rt6_info ip6_pol_route_lookup(struct net net,
794	struct fib6_table *table,	793	struct fib6_table *table,
@@ -804,8 +803,11 @@ restart:
804	rt = rt6_device_match(net, rt, &fl6->saddr, fl6->flowi6_oif, flags);	803	rt = rt6_device_match(net, rt, &fl6->saddr, fl6->flowi6_oif, flags);
805	if (rt->rt6i_nsiblings && fl6->flowi6_oif == 0)	804	if (rt->rt6i_nsiblings && fl6->flowi6_oif == 0)
806	rt = rt6_multipath_select(rt, fl6, fl6->flowi6_oif, flags);	805	rt = rt6_multipath_select(rt, fl6, fl6->flowi6_oif, flags);
807	BACKTRACK(net, &fl6->saddr);	806	if (rt == net->ipv6.ip6_null_entry) {
808	out:	807	fn = fib6_backtrack(fn, &fl6->saddr);
		808	if (fn)
		809	goto restart;
		810	}
809	dst_use(&rt->dst, jiffies);	811	dst_use(&rt->dst, jiffies);
810	read_unlock_bh(&table->tb6_lock);	812	read_unlock_bh(&table->tb6_lock);
811	return rt;	813	return rt;
@@ -924,19 +926,25 @@ static struct rt6_info ip6_pol_route(struct net net, struct fib6_table *table,
924		926
925	strict \|= flags & RT6_LOOKUP_F_IFACE;	927	strict \|= flags & RT6_LOOKUP_F_IFACE;
926		928
927	relookup:	929	redo_fib6_lookup_lock:
928	read_lock_bh(&table->tb6_lock);	930	read_lock_bh(&table->tb6_lock);
929		931
930	restart_2:	932	redo_fib6_lookup:
931	fn = fib6_lookup(&table->tb6_root, &fl6->daddr, &fl6->saddr);	933	fn = fib6_lookup(&table->tb6_root, &fl6->daddr, &fl6->saddr);
932		934
933	restart:	935	redo_rt6_select:
934	rt = rt6_select(fn, oif, strict \| reachable);	936	rt = rt6_select(fn, oif, strict \| reachable);
935	if (rt->rt6i_nsiblings)	937	if (rt->rt6i_nsiblings)
936	rt = rt6_multipath_select(rt, fl6, oif, strict \| reachable);	938	rt = rt6_multipath_select(rt, fl6, oif, strict \| reachable);
937	BACKTRACK(net, &fl6->saddr);	939	if (rt == net->ipv6.ip6_null_entry) {
938	if (rt == net->ipv6.ip6_null_entry \|\|	940	fn = fib6_backtrack(fn, &fl6->saddr);
939	rt->rt6i_flags & RTF_CACHE)	941	if (fn)
		942	goto redo_rt6_select;
		943	else
		944	goto out;
		945	}
		946
		947	if (rt->rt6i_flags & RTF_CACHE)
940	goto out;	948	goto out;
941		949
942	dst_hold(&rt->dst);	950	dst_hold(&rt->dst);
@@ -967,12 +975,12 @@ restart:
967	* released someone could insert this route. Relookup.	975	* released someone could insert this route. Relookup.
968	*/	976	*/
969	ip6_rt_put(rt);	977	ip6_rt_put(rt);
970	goto relookup;	978	goto redo_fib6_lookup_lock;
971		979
972	out:	980	out:
973	if (reachable) {	981	if (reachable) {
974	reachable = 0;	982	reachable = 0;
975	goto restart_2;	983	goto redo_fib6_lookup;
976	}	984	}
977	dst_hold(&rt->dst);	985	dst_hold(&rt->dst);
978	read_unlock_bh(&table->tb6_lock);	986	read_unlock_bh(&table->tb6_lock);
@@ -1235,10 +1243,12 @@ restart:
1235	rt = net->ipv6.ip6_null_entry;	1243	rt = net->ipv6.ip6_null_entry;
1236	else if (rt->dst.error) {	1244	else if (rt->dst.error) {
1237	rt = net->ipv6.ip6_null_entry;	1245	rt = net->ipv6.ip6_null_entry;
1238	goto out;	1246	} else if (rt == net->ipv6.ip6_null_entry) {
		1247	fn = fib6_backtrack(fn, &fl6->saddr);
		1248	if (fn)
		1249	goto restart;
1239	}	1250	}
1240	BACKTRACK(net, &fl6->saddr);	1251
1241	out:
1242	dst_hold(&rt->dst);	1252	dst_hold(&rt->dst);
1243		1253
1244	read_unlock_bh(&table->tb6_lock);	1254	read_unlock_bh(&table->tb6_lock);