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-rw-r--r--target/linux/generic/pending-3.18/080-09-fib_trie-Update-meaning-of-pos-to-represent-unchecke.patch346
1 files changed, 0 insertions, 346 deletions
diff --git a/target/linux/generic/pending-3.18/080-09-fib_trie-Update-meaning-of-pos-to-represent-unchecke.patch b/target/linux/generic/pending-3.18/080-09-fib_trie-Update-meaning-of-pos-to-represent-unchecke.patch
deleted file mode 100644
index a0d34762b8..0000000000
--- a/target/linux/generic/pending-3.18/080-09-fib_trie-Update-meaning-of-pos-to-represent-unchecke.patch
+++ /dev/null
@@ -1,346 +0,0 @@
-From: Alexander Duyck <alexander.h.duyck@redhat.com>
-Date: Wed, 31 Dec 2014 10:56:12 -0800
-Subject: [PATCH] fib_trie: Update meaning of pos to represent unchecked
- bits
-
-This change moves the pos value to the other side of the "bits" field. By
-doing this it actually simplifies a significant amount of code in the trie.
-
-For example when halving a tree we know that the bit lost exists at
-oldnode->pos, and if we inflate the tree the new bit being add is at
-tn->pos. Previously to find those bits you would have to subtract pos and
-bits from the keylength or start with a value of (1 << 31) and then shift
-that.
-
-There are a number of spots throughout the code that benefit from this. In
-the case of the hot-path searches the main advantage is that we can drop 2
-or more operations from the search path as we no longer need to compute the
-value for the index to be shifted by and can instead just use the raw pos
-value.
-
-In addition the tkey_extract_bits is now defunct and can be replaced by
-get_index since the two operations were doing the same thing, but now
-get_index does it much more quickly as it is only an xor and shift versus a
-pair of shifts and a subtraction.
-
-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
-@@ -90,8 +90,7 @@ typedef unsigned int t_key;
- #define IS_TNODE(n) ((n)->bits)
- #define IS_LEAF(n) (!(n)->bits)
-
--#define get_shift(_kv) (KEYLENGTH - (_kv)->pos - (_kv)->bits)
--#define get_index(_key, _kv) (((_key) ^ (_kv)->key) >> get_shift(_kv))
-+#define get_index(_key, _kv) (((_key) ^ (_kv)->key) >> (_kv)->pos)
-
- struct tnode {
- t_key key;
-@@ -209,81 +208,64 @@ static inline struct tnode *tnode_get_ch
- return rcu_dereference_rtnl(tn->child[i]);
- }
-
--static inline t_key mask_pfx(t_key k, unsigned int l)
--{
-- return (l == 0) ? 0 : k >> (KEYLENGTH-l) << (KEYLENGTH-l);
--}
--
--static inline t_key tkey_extract_bits(t_key a, unsigned int offset, unsigned int bits)
--{
-- if (offset < KEYLENGTH)
-- return ((t_key)(a << offset)) >> (KEYLENGTH - bits);
-- else
-- return 0;
--}
--
--/*
-- To understand this stuff, an understanding of keys and all their bits is
-- necessary. Every node in the trie has a key associated with it, but not
-- all of the bits in that key are significant.
--
-- Consider a node 'n' and its parent 'tp'.
--
-- If n is a leaf, every bit in its key is significant. Its presence is
-- necessitated by path compression, since during a tree traversal (when
-- searching for a leaf - unless we are doing an insertion) we will completely
-- ignore all skipped bits we encounter. Thus we need to verify, at the end of
-- a potentially successful search, that we have indeed been walking the
-- correct key path.
--
-- Note that we can never "miss" the correct key in the tree if present by
-- following the wrong path. Path compression ensures that segments of the key
-- that are the same for all keys with a given prefix are skipped, but the
-- skipped part *is* identical for each node in the subtrie below the skipped
-- bit! trie_insert() in this implementation takes care of that - note the
-- call to tkey_sub_equals() in trie_insert().
--
-- if n is an internal node - a 'tnode' here, the various parts of its key
-- have many different meanings.
--
-- Example:
-- _________________________________________________________________
-- | i | i | i | i | i | i | i | N | N | N | S | S | S | S | S | C |
-- -----------------------------------------------------------------
-- 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
--
-- _________________________________________________________________
-- | C | C | C | u | u | u | u | u | u | u | u | u | u | u | u | u |
-- -----------------------------------------------------------------
-- 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31
--
-- tp->pos = 7
-- tp->bits = 3
-- n->pos = 15
-- n->bits = 4
--
-- First, let's just ignore the bits that come before the parent tp, that is
-- the bits from 0 to (tp->pos-1). They are *known* but at this point we do
-- not use them for anything.
--
-- The bits from (tp->pos) to (tp->pos + tp->bits - 1) - "N", above - are the
-- index into the parent's child array. That is, they will be used to find
-- 'n' among tp's children.
--
-- The bits from (tp->pos + tp->bits) to (n->pos - 1) - "S" - are skipped bits
-- for the node n.
--
-- All the bits we have seen so far are significant to the node n. The rest
-- of the bits are really not needed or indeed known in n->key.
--
-- The bits from (n->pos) to (n->pos + n->bits - 1) - "C" - are the index into
-- n's child array, and will of course be different for each child.
--
--
-- The rest of the bits, from (n->pos + n->bits) onward, are completely unknown
-- at this point.
--
--*/
-+/* To understand this stuff, an understanding of keys and all their bits is
-+ * necessary. Every node in the trie has a key associated with it, but not
-+ * all of the bits in that key are significant.
-+ *
-+ * Consider a node 'n' and its parent 'tp'.
-+ *
-+ * If n is a leaf, every bit in its key is significant. Its presence is
-+ * necessitated by path compression, since during a tree traversal (when
-+ * searching for a leaf - unless we are doing an insertion) we will completely
-+ * ignore all skipped bits we encounter. Thus we need to verify, at the end of
-+ * a potentially successful search, that we have indeed been walking the
-+ * correct key path.
-+ *
-+ * Note that we can never "miss" the correct key in the tree if present by
-+ * following the wrong path. Path compression ensures that segments of the key
-+ * that are the same for all keys with a given prefix are skipped, but the
-+ * skipped part *is* identical for each node in the subtrie below the skipped
-+ * bit! trie_insert() in this implementation takes care of that.
-+ *
-+ * if n is an internal node - a 'tnode' here, the various parts of its key
-+ * have many different meanings.
-+ *
-+ * Example:
-+ * _________________________________________________________________
-+ * | i | i | i | i | i | i | i | N | N | N | S | S | S | S | S | C |
-+ * -----------------------------------------------------------------
-+ * 31 30 29 28 27 26 25 24 23 22 21 20 19 18 17 16
-+ *
-+ * _________________________________________________________________
-+ * | C | C | C | u | u | u | u | u | u | u | u | u | u | u | u | u |
-+ * -----------------------------------------------------------------
-+ * 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 0
-+ *
-+ * tp->pos = 22
-+ * tp->bits = 3
-+ * n->pos = 13
-+ * n->bits = 4
-+ *
-+ * First, let's just ignore the bits that come before the parent tp, that is
-+ * the bits from (tp->pos + tp->bits) to 31. They are *known* but at this
-+ * point we do not use them for anything.
-+ *
-+ * The bits from (tp->pos) to (tp->pos + tp->bits - 1) - "N", above - are the
-+ * index into the parent's child array. That is, they will be used to find
-+ * 'n' among tp's children.
-+ *
-+ * The bits from (n->pos + n->bits) to (tn->pos - 1) - "S" - are skipped bits
-+ * for the node n.
-+ *
-+ * All the bits we have seen so far are significant to the node n. The rest
-+ * of the bits are really not needed or indeed known in n->key.
-+ *
-+ * The bits from (n->pos) to (n->pos + n->bits - 1) - "C" - are the index into
-+ * n's child array, and will of course be different for each child.
-+ *
-+ * The rest of the bits, from 0 to (n->pos + n->bits), are completely unknown
-+ * at this point.
-+ */
-
- static const int halve_threshold = 25;
- static const int inflate_threshold = 50;
-@@ -367,7 +349,7 @@ static struct tnode *leaf_new(t_key key)
- * as the nodes are searched
- */
- l->key = key;
-- l->pos = KEYLENGTH;
-+ l->pos = 0;
- /* set bits to 0 indicating we are not a tnode */
- l->bits = 0;
-
-@@ -400,7 +382,7 @@ static struct tnode *tnode_new(t_key key
- tn->parent = NULL;
- tn->pos = pos;
- tn->bits = bits;
-- tn->key = mask_pfx(key, pos);
-+ tn->key = (shift < KEYLENGTH) ? (key >> shift) << shift : 0;
- tn->full_children = 0;
- tn->empty_children = 1<<bits;
- }
-@@ -410,14 +392,12 @@ static struct tnode *tnode_new(t_key key
- return tn;
- }
-
--/*
-- * Check whether a tnode 'n' is "full", i.e. it is an internal node
-+/* Check whether a tnode 'n' is "full", i.e. it is an internal node
- * and no bits are skipped. See discussion in dyntree paper p. 6
- */
--
- static inline int tnode_full(const struct tnode *tn, const struct tnode *n)
- {
-- return n && IS_TNODE(n) && (n->pos == (tn->pos + tn->bits));
-+ return n && ((n->pos + n->bits) == tn->pos) && IS_TNODE(n);
- }
-
- static inline void put_child(struct tnode *tn, int i,
-@@ -641,11 +621,12 @@ static struct tnode *inflate(struct trie
- {
- int olen = tnode_child_length(oldtnode);
- struct tnode *tn;
-+ t_key m;
- int i;
-
- pr_debug("In inflate\n");
-
-- tn = tnode_new(oldtnode->key, oldtnode->pos, oldtnode->bits + 1);
-+ tn = tnode_new(oldtnode->key, oldtnode->pos - 1, oldtnode->bits + 1);
-
- if (!tn)
- return ERR_PTR(-ENOMEM);
-@@ -656,21 +637,18 @@ static struct tnode *inflate(struct trie
- * fails. In case of failure we return the oldnode and inflate
- * of tnode is ignored.
- */
-+ for (i = 0, m = 1u << tn->pos; i < olen; i++) {
-+ struct tnode *inode = tnode_get_child(oldtnode, i);
-
-- for (i = 0; i < olen; i++) {
-- struct tnode *inode;
--
-- inode = tnode_get_child(oldtnode, i);
-- if (tnode_full(oldtnode, inode) && inode->bits > 1) {
-+ if (tnode_full(oldtnode, inode) && (inode->bits > 1)) {
- struct tnode *left, *right;
-- t_key m = ~0U << (KEYLENGTH - 1) >> inode->pos;
-
-- left = tnode_new(inode->key&(~m), inode->pos + 1,
-+ left = tnode_new(inode->key & ~m, inode->pos,
- inode->bits - 1);
- if (!left)
- goto nomem;
-
-- right = tnode_new(inode->key|m, inode->pos + 1,
-+ right = tnode_new(inode->key | m, inode->pos,
- inode->bits - 1);
-
- if (!right) {
-@@ -694,9 +672,7 @@ static struct tnode *inflate(struct trie
-
- /* A leaf or an internal node with skipped bits */
- if (!tnode_full(oldtnode, inode)) {
-- put_child(tn,
-- tkey_extract_bits(inode->key, tn->pos, tn->bits),
-- inode);
-+ put_child(tn, get_index(inode->key, tn), inode);
- continue;
- }
-
-@@ -767,7 +743,7 @@ static struct tnode *halve(struct trie *
-
- pr_debug("In halve\n");
-
-- tn = tnode_new(oldtnode->key, oldtnode->pos, oldtnode->bits - 1);
-+ tn = tnode_new(oldtnode->key, oldtnode->pos + 1, oldtnode->bits - 1);
-
- if (!tn)
- return ERR_PTR(-ENOMEM);
-@@ -787,7 +763,7 @@ static struct tnode *halve(struct trie *
- if (left && right) {
- struct tnode *newn;
-
-- newn = tnode_new(left->key, tn->pos + tn->bits, 1);
-+ newn = tnode_new(left->key, oldtnode->pos, 1);
-
- if (!newn)
- goto nomem;
-@@ -915,7 +891,7 @@ static void trie_rebalance(struct trie *
- key = tn->key;
-
- while (tn != NULL && (tp = node_parent(tn)) != NULL) {
-- cindex = tkey_extract_bits(key, tp->pos, tp->bits);
-+ cindex = get_index(key, tp);
- wasfull = tnode_full(tp, tnode_get_child(tp, cindex));
- tn = resize(t, tn);
-
-@@ -1005,11 +981,8 @@ static struct list_head *fib_insert_node
- */
- if (n) {
- struct tnode *tn;
-- int newpos;
--
-- newpos = KEYLENGTH - __fls(n->key ^ key) - 1;
-
-- tn = tnode_new(key, newpos, 1);
-+ tn = tnode_new(key, __fls(key ^ n->key), 1);
- if (!tn) {
- free_leaf_info(li);
- node_free(l);
-@@ -1559,12 +1532,7 @@ static int trie_flush_leaf(struct tnode
- static struct tnode *leaf_walk_rcu(struct tnode *p, struct tnode *c)
- {
- do {
-- t_key idx;
--
-- if (c)
-- idx = tkey_extract_bits(c->key, p->pos, p->bits) + 1;
-- else
-- idx = 0;
-+ t_key idx = c ? idx = get_index(c->key, p) + 1 : 0;
-
- while (idx < 1u << p->bits) {
- c = tnode_get_child_rcu(p, idx++);
-@@ -1851,7 +1819,7 @@ rescan:
- /* Current node exhausted, pop back up */
- p = node_parent_rcu(tn);
- if (p) {
-- cindex = tkey_extract_bits(tn->key, p->pos, p->bits)+1;
-+ cindex = get_index(tn->key, p) + 1;
- tn = p;
- --iter->depth;
- goto rescan;
-@@ -2186,10 +2154,10 @@ static int fib_trie_seq_show(struct seq_
- if (IS_TNODE(n)) {
- __be32 prf = htonl(n->key);
-
-- seq_indent(seq, iter->depth - 1);
-- seq_printf(seq, " +-- %pI4/%d %d %d %d\n",
-- &prf, n->pos, n->bits, n->full_children,
-- n->empty_children);
-+ seq_indent(seq, iter->depth-1);
-+ seq_printf(seq, " +-- %pI4/%zu %u %u %u\n",
-+ &prf, KEYLENGTH - n->pos - n->bits, n->bits,
-+ n->full_children, n->empty_children);
- } else {
- struct leaf_info *li;
- __be32 val = htonl(n->key);
generated by cgit v1.2.3 (git 2.25.1) at 2024-07-25 13:56:28 +0000