1 files changed, 95 insertions, 0 deletions
diff --git a/target/linux/generic/patches-3.18/080-17-fib_trie-Remove-checks-for-index-tnode_child_length-.patch b/target/linux/generic/patches-3.18/080-17-fib_trie-Remove-checks-for-index-tnode_child_length-.patch
new file mode 100644
index 0000000..8f7c671
--- /dev/null
+++ b/target/linux/generic/patches-3.18/080-17-fib_trie-Remove-checks-for-index-tnode_child_length-.patch
@@ -0,0 +1,95 @@
+From: Alexander Duyck <alexander.h.duyck@redhat.com>
+Date: Wed, 31 Dec 2014 10:57:02 -0800
+Subject: [PATCH] fib_trie: Remove checks for index >= tnode_child_length
+ from tnode_get_child
+
+For some reason the compiler doesn't seem to understand that when we are in
+a loop that runs from tnode_child_length - 1 to 0 we don't expect the value
+of tn->bits to change.  As such every call to tnode_get_child was rerunning
+tnode_chile_length which ended up consuming quite a bit of space in the
+resultant assembly code.
+
+I have gone though and verified that in all cases where tnode_get_child
+is used we are either winding though a fixed loop from tnode_child_length -
+1 to 0, or are in a fastpath case where we are verifying the value by
+either checking for any remaining bits after shifting index by bits and
+testing for leaf, or by using tnode_child_length.
+
+size net/ipv4/fib_trie.o
+Before:
+   text	   data	    bss	    dec	    hex	filename
+  15506	    376	      8	  15890	   3e12	net/ipv4/fib_trie.o
+
+After:
+   text	   data	    bss	    dec	    hex	filename
+  14827	    376	      8	  15211	   3b6b	net/ipv4/fib_trie.o
+
+Signed-off-by: Alexander Duyck <alexander.h.duyck@redhat.com>
+Signed-off-by: David S. Miller <davem@davemloft.net>
+---
+
+--- a/net/ipv4/fib_trie.c
++++ b/net/ipv4/fib_trie.c
+@@ -186,8 +186,6 @@ static inline unsigned long tnode_child_
+ static inline struct tnode *tnode_get_child(const struct tnode *tn,
+ 					    unsigned long i)
+ {
+-	BUG_ON(i >= tnode_child_length(tn));
+-
+ 	return rtnl_dereference(tn->child[i]);
+ }
+ 
+@@ -195,8 +193,6 @@ static inline struct tnode *tnode_get_ch
+ static inline struct tnode *tnode_get_child_rcu(const struct tnode *tn,
+ 						unsigned long i)
+ {
+-	BUG_ON(i >= tnode_child_length(tn));
+-
+ 	return rcu_dereference_rtnl(tn->child[i]);
+ }
+ 
+@@ -371,7 +367,7 @@ static inline int tnode_full(const struc
+  */
+ static void put_child(struct tnode *tn, unsigned long i, struct tnode *n)
+ {
+-	struct tnode *chi = rtnl_dereference(tn->child[i]);
++	struct tnode *chi = tnode_get_child(tn, i);
+ 	int isfull, wasfull;
+ 
+ 	BUG_ON(i >= tnode_child_length(tn));
+@@ -867,7 +863,7 @@ static struct tnode *fib_find_node(struc
+ 		if (IS_LEAF(n))
+ 			break;
+ 
+-		n = rcu_dereference_rtnl(n->child[index]);
++		n = tnode_get_child_rcu(n, index);
+ 	}
+ 
+ 	return n;
+@@ -934,7 +930,7 @@ static struct list_head *fib_insert_node
+ 		}
+ 
+ 		tp = n;
+-		n = rcu_dereference_rtnl(n->child[index]);
++		n = tnode_get_child_rcu(n, index);
+ 	}
+ 
+ 	l = leaf_new(key);
+@@ -1215,7 +1211,7 @@ int fib_table_lookup(struct fib_table *t
+ 			cindex = index;
+ 		}
+ 
+-		n = rcu_dereference(n->child[index]);
++		n = tnode_get_child_rcu(n, index);
+ 		if (unlikely(!n))
+ 			goto backtrace;
+ 	}
+@@ -1835,7 +1831,7 @@ static void trie_collect_stats(struct tr
+ 			if (n->bits < MAX_STAT_DEPTH)
+ 				s->nodesizes[n->bits]++;
+ 
+-			for (i = 0; i < tnode_child_length(n); i++) {
++			for (i = tnode_child_length(n); i--;) {
+ 				if (!rcu_access_pointer(n->child[i]))
+ 					s->nullpointers++;
+ 			}