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Commit 8d8e810c authored by Alexander Duyck's avatar Alexander Duyck Committed by David S. Miller
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fib_trie: Return pointer to tnode pointer in resize/inflate/halve 



Resize related functions now all return a pointer to the pointer that
references the object that was resized.

Signed-off-by: default avatarAlexander Duyck <alexander.h.duyck@redhat.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 72be7260

net/ipv4/fib_trie.c

+65 −41
Original line number Diff line number Diff line
@@ -144,7 +144,7 @@ struct trie { 
#endif

};



static void resize(struct trie *t, struct tnode *tn);

static struct tnode **resize(struct trie *t, struct tnode *tn);

static size_t tnode_free_size;



/*
@@ -468,9 +468,11 @@ static void tnode_free(struct tnode *tn) 
	}

}



static void replace(struct trie *t, struct tnode *oldtnode, struct tnode *tn)

static struct tnode __rcu **replace(struct trie *t, struct tnode *oldtnode,

				    struct tnode *tn)

{

	struct tnode *tp = node_parent(oldtnode);

	struct tnode **cptr;

	unsigned long i;



	/* setup the parent pointer out of and back into this node */
@@ -483,6 +485,9 @@ static void replace(struct trie *t, struct tnode *oldtnode, struct tnode *tn) 
	/* all pointers should be clean so we are done */

	tnode_free(oldtnode);



	/* record the pointer that is pointing to this node */

	cptr = tp ? tp->tnode : &t->trie;



	/* resize children now that oldtnode is freed */

	for (i = tnode_child_length(tn); i;) {

		struct tnode *inode = tnode_get_child(tn, --i);
@@ -491,9 +496,11 @@ static void replace(struct trie *t, struct tnode *oldtnode, struct tnode *tn) 
		if (tnode_full(tn, inode))

			resize(t, inode);

	}



	return cptr;

}



static int inflate(struct trie *t, struct tnode *oldtnode)

static struct tnode __rcu **inflate(struct trie *t, struct tnode *oldtnode)

{

	struct tnode *tn;

	unsigned long i;
@@ -503,7 +510,7 @@ static int inflate(struct trie *t, struct tnode *oldtnode) 


	tn = tnode_new(oldtnode->key, oldtnode->pos - 1, oldtnode->bits + 1);

	if (!tn)

		return -ENOMEM;

		goto notnode;



	/* prepare oldtnode to be freed */

	tnode_free_init(oldtnode);
@@ -580,16 +587,15 @@ static int inflate(struct trie *t, struct tnode *oldtnode) 
	}



	/* setup the parent pointers into and out of this node */

	replace(t, oldtnode, tn);



	return 0;

	return replace(t, oldtnode, tn);

nomem:

	/* all pointers should be clean so we are done */

	tnode_free(tn);

	return -ENOMEM;

notnode:

	return NULL;

}



static int halve(struct trie *t, struct tnode *oldtnode)

static struct tnode __rcu **halve(struct trie *t, struct tnode *oldtnode)

{

	struct tnode *tn;

	unsigned long i;
@@ -598,7 +604,7 @@ static int halve(struct trie *t, struct tnode *oldtnode) 


	tn = tnode_new(oldtnode->key, oldtnode->pos + 1, oldtnode->bits - 1);

	if (!tn)

		return -ENOMEM;

		goto notnode;



	/* prepare oldtnode to be freed */

	tnode_free_init(oldtnode);
@@ -621,10 +627,8 @@ static int halve(struct trie *t, struct tnode *oldtnode) 


		/* Two nonempty children */

		inode = tnode_new(node0->key, oldtnode->pos, 1);

		if (!inode) {

			tnode_free(tn);

			return -ENOMEM;

		}

		if (!inode)

			goto nomem;

		tnode_free_append(tn, inode);



		/* initialize pointers out of node */
@@ -637,9 +641,12 @@ static int halve(struct trie *t, struct tnode *oldtnode) 
	}



	/* setup the parent pointers into and out of this node */

	replace(t, oldtnode, tn);



	return 0;

	return replace(t, oldtnode, tn);

nomem:

	/* all pointers should be clean so we are done */

	tnode_free(tn);

notnode:

	return NULL;

}



static void collapse(struct trie *t, struct tnode *oldtnode)
@@ -796,10 +803,14 @@ static bool should_collapse(const struct tnode *tn) 
}



#define MAX_WORK 10

static void resize(struct trie *t, struct tnode *tn)

static struct tnode __rcu **resize(struct trie *t, struct tnode *tn)

{

#ifdef CONFIG_IP_FIB_TRIE_STATS

	struct trie_use_stats __percpu *stats = t->stats;

#endif

	struct tnode *tp = node_parent(tn);

	struct tnode __rcu **cptr;

	unsigned long cindex = tp ? get_index(tn->key, tp) : 0;

	struct tnode __rcu **cptr = tp ? tp->tnode : &t->trie;

	int max_work = MAX_WORK;



	pr_debug("In tnode_resize %p inflate_threshold=%d threshold=%d\n",
@@ -809,52 +820,57 @@ static void resize(struct trie *t, struct tnode *tn) 
	 * doing it ourselves.  This way we can let RCU fully do its

	 * thing without us interfering

	 */

	cptr = tp ? &tp->tnode[get_index(tn->key, tp)] : &t->trie;

	BUG_ON(tn != rtnl_dereference(*cptr));

	BUG_ON(tn != rtnl_dereference(cptr[cindex]));



	/* Double as long as the resulting node has a number of

	 * nonempty nodes that are above the threshold.

	 */

	while (should_inflate(tp, tn) && max_work) {

		if (inflate(t, tn)) {

		struct tnode __rcu **tcptr = inflate(t, tn);



		if (!tcptr) {

#ifdef CONFIG_IP_FIB_TRIE_STATS

			this_cpu_inc(t->stats->resize_node_skipped);

			this_cpu_inc(stats->resize_node_skipped);

#endif

			break;

		}



		max_work--;

		tn = rtnl_dereference(*cptr);

		cptr = tcptr;

		tn = rtnl_dereference(cptr[cindex]);

	}



	/* Return if at least one inflate is run */

	if (max_work != MAX_WORK)

		return;

		return cptr;



	/* Halve as long as the number of empty children in this

	 * node is above threshold.

	 */

	while (should_halve(tp, tn) && max_work) {

		if (halve(t, tn)) {

		struct tnode __rcu **tcptr = halve(t, tn);



		if (!tcptr) {

#ifdef CONFIG_IP_FIB_TRIE_STATS

			this_cpu_inc(t->stats->resize_node_skipped);

			this_cpu_inc(stats->resize_node_skipped);

#endif

			break;

		}



		max_work--;

		tn = rtnl_dereference(*cptr);

		cptr = tcptr;

		tn = rtnl_dereference(cptr[cindex]);

	}



	/* Only one child remains */

	if (should_collapse(tn)) {

		collapse(t, tn);

		return;

		return cptr;

	}



	/* Return if at least one deflate was run */

	if (max_work != MAX_WORK)

		return;

		return cptr;



	/* push the suffix length to the parent node */

	if (tn->slen > tn->pos) {
@@ -863,6 +879,8 @@ static void resize(struct trie *t, struct tnode *tn) 
		if (tp && (slen > tp->slen))

			tp->slen = slen;

	}



	return cptr;

}



static void leaf_pull_suffix(struct tnode *tp, struct tnode *l)
@@ -952,16 +970,18 @@ static struct fib_alias *fib_find_alias(struct hlist_head *fah, u8 slen, 


static void trie_rebalance(struct trie *t, struct tnode *tn)

{

	struct tnode *tp;

	struct tnode __rcu **cptr = &t->trie;



	while (tn) {

		tp = node_parent(tn);

		resize(t, tn);

		tn = tp;

		struct tnode *tp = node_parent(tn);



		cptr = resize(t, tn);

		if (!tp)

			break;

		tn = container_of(cptr, struct tnode, tnode[0]);

	}

}



/* only used from updater-side */

static int fib_insert_node(struct trie *t, struct tnode *tp,

			   struct fib_alias *new, t_key key)

{
@@ -969,7 +989,7 @@ static int fib_insert_node(struct trie *t, struct tnode *tp, 


	l = leaf_new(key, new);

	if (!l)

		return -ENOMEM;

		goto noleaf;



	/* retrieve child from parent node */

	if (tp)
@@ -987,10 +1007,8 @@ static int fib_insert_node(struct trie *t, struct tnode *tp, 
		struct tnode *tn;



		tn = tnode_new(key, __fls(key ^ n->key), 1);

		if (!tn) {

			node_free(l);

			return -ENOMEM;

		}

		if (!tn)

			goto notnode;



		/* initialize routes out of node */

		NODE_INIT_PARENT(tn, tp);
@@ -1010,6 +1028,10 @@ static int fib_insert_node(struct trie *t, struct tnode *tp, 
	trie_rebalance(t, tp);



	return 0;

notnode:

	node_free(l);

noleaf:

	return -ENOMEM;

}



static int fib_insert_alias(struct trie *t, struct tnode *tp,
@@ -1642,18 +1664,20 @@ int fib_table_flush(struct fib_table *tb) 
		/* walk trie in reverse order */

		do {

			while (!(cindex--)) {

				struct tnode __rcu **cptr;

				t_key pkey = pn->key;



				n = pn;

				pn = node_parent(n);



				/* resize completed node */

				resize(t, n);

				cptr = resize(t, n);



				/* if we got the root we are done */

				if (!pn)

					goto flush_complete;



				pn = container_of(cptr, struct tnode, tnode[0]);

				cindex = get_index(pkey, pn);

			}