Commit 9e85d811 authored by Matthew Wilcox's avatar Matthew Wilcox Committed by Linus Torvalds
Browse files

radix-tree: make radix_tree_descend() more useful 



Now that the shift amount is stored in the node, radix_tree_descend()
can calculate offset itself from index, which removes several lines of
code from each of the tree walkers.

Signed-off-by: default avatarMatthew Wilcox <willy@linux.intel.com>
Cc: Konstantin Khlebnikov <koct9i@gmail.com>
Cc: Kirill Shutemov <kirill.shutemov@linux.intel.com>
Cc: Jan Kara <jack@suse.com>
Cc: Neil Brown <neilb@suse.de>
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent d604c324

lib/radix-tree.c

+26 −52
Original line number Diff line number Diff line
@@ -94,9 +94,10 @@ static inline unsigned long get_slot_offset(struct radix_tree_node *parent, 
	return slot - parent->slots;

}



static unsigned radix_tree_descend(struct radix_tree_node *parent,

				struct radix_tree_node **nodep, unsigned offset)

static unsigned int radix_tree_descend(struct radix_tree_node *parent,

			struct radix_tree_node **nodep, unsigned long index)

{

	unsigned int offset = (index >> parent->shift) & RADIX_TREE_MAP_MASK;

	void **entry = rcu_dereference_raw(parent->slots[offset]);



#ifdef CONFIG_RADIX_TREE_MULTIORDER
@@ -536,8 +537,7 @@ int __radix_tree_create(struct radix_tree_root *root, unsigned long index, 


		/* Go a level down */

		node = entry_to_node(child);

		offset = (index >> shift) & RADIX_TREE_MAP_MASK;

		offset = radix_tree_descend(node, &child, offset);

		offset = radix_tree_descend(node, &child, index);

		slot = &node->slots[offset];

	}
@@ -625,13 +625,12 @@ void *__radix_tree_lookup(struct radix_tree_root *root, unsigned long index, 
{

	struct radix_tree_node *node, *parent;

	unsigned long maxindex;

	unsigned int shift;

	void **slot;



 restart:

	parent = NULL;

	slot = (void **)&root->rnode;

	shift = radix_tree_load_root(root, &node, &maxindex);

	radix_tree_load_root(root, &node, &maxindex);

	if (index > maxindex)

		return NULL;
@@ -641,9 +640,7 @@ void *__radix_tree_lookup(struct radix_tree_root *root, unsigned long index, 
		if (node == RADIX_TREE_RETRY)

			goto restart;

		parent = entry_to_node(node);

		shift -= RADIX_TREE_MAP_SHIFT;

		offset = (index >> shift) & RADIX_TREE_MAP_MASK;

		offset = radix_tree_descend(parent, &node, offset);

		offset = radix_tree_descend(parent, &node, index);

		slot = parent->slots + offset;

	}
@@ -713,19 +710,15 @@ void *radix_tree_tag_set(struct radix_tree_root *root, 
{

	struct radix_tree_node *node, *parent;

	unsigned long maxindex;

	unsigned int shift;



	shift = radix_tree_load_root(root, &node, &maxindex);

	radix_tree_load_root(root, &node, &maxindex);

	BUG_ON(index > maxindex);



	while (radix_tree_is_internal_node(node)) {

		unsigned offset;



		shift -= RADIX_TREE_MAP_SHIFT;

		offset = (index >> shift) & RADIX_TREE_MAP_MASK;



		parent = entry_to_node(node);

		offset = radix_tree_descend(parent, &node, offset);

		offset = radix_tree_descend(parent, &node, index);

		BUG_ON(!node);



		if (!tag_get(parent, tag, offset))
@@ -779,21 +772,17 @@ void *radix_tree_tag_clear(struct radix_tree_root *root, 
{

	struct radix_tree_node *node, *parent;

	unsigned long maxindex;

	unsigned int shift;

	int uninitialized_var(offset);



	shift = radix_tree_load_root(root, &node, &maxindex);

	radix_tree_load_root(root, &node, &maxindex);

	if (index > maxindex)

		return NULL;



	parent = NULL;



	while (radix_tree_is_internal_node(node)) {

		shift -= RADIX_TREE_MAP_SHIFT;

		offset = (index >> shift) & RADIX_TREE_MAP_MASK;



		parent = entry_to_node(node);

		offset = radix_tree_descend(parent, &node, offset);

		offset = radix_tree_descend(parent, &node, index);

	}



	if (node)
@@ -823,25 +812,21 @@ int radix_tree_tag_get(struct radix_tree_root *root, 
{

	struct radix_tree_node *node, *parent;

	unsigned long maxindex;

	unsigned int shift;



	if (!root_tag_get(root, tag))

		return 0;



	shift = radix_tree_load_root(root, &node, &maxindex);

	radix_tree_load_root(root, &node, &maxindex);

	if (index > maxindex)

		return 0;

	if (node == NULL)

		return 0;



	while (radix_tree_is_internal_node(node)) {

		int offset;



		shift -= RADIX_TREE_MAP_SHIFT;

		offset = (index >> shift) & RADIX_TREE_MAP_MASK;

		unsigned offset;



		parent = entry_to_node(node);

		offset = radix_tree_descend(parent, &node, offset);

		offset = radix_tree_descend(parent, &node, index);



		if (!node)

			return 0;
@@ -874,7 +859,7 @@ static inline void __set_iter_shift(struct radix_tree_iter *iter, 
void **radix_tree_next_chunk(struct radix_tree_root *root,

			     struct radix_tree_iter *iter, unsigned flags)

{

	unsigned shift, tag = flags & RADIX_TREE_ITER_TAG_MASK;

	unsigned tag = flags & RADIX_TREE_ITER_TAG_MASK;

	struct radix_tree_node *node, *child;

	unsigned long index, offset, maxindex;
@@ -895,7 +880,7 @@ void **radix_tree_next_chunk(struct radix_tree_root *root, 
		return NULL;



 restart:

	shift = radix_tree_load_root(root, &child, &maxindex);

	radix_tree_load_root(root, &child, &maxindex);

	if (index > maxindex)

		return NULL;

	if (!child)
@@ -912,9 +897,7 @@ void **radix_tree_next_chunk(struct radix_tree_root *root, 


	do {

		node = entry_to_node(child);

		shift -= RADIX_TREE_MAP_SHIFT;

		offset = (index >> shift) & RADIX_TREE_MAP_MASK;

		offset = radix_tree_descend(node, &child, offset);

		offset = radix_tree_descend(node, &child, index);



		if ((flags & RADIX_TREE_ITER_TAGGED) ?

				!tag_get(node, tag, offset) : !child) {
@@ -936,7 +919,7 @@ void **radix_tree_next_chunk(struct radix_tree_root *root, 
						break;

				}

			index &= ~node_maxindex(node);

			index += offset << shift;

			index += offset << node->shift;

			/* Overflow after ~0UL */

			if (!index)

				return NULL;
@@ -952,7 +935,7 @@ void **radix_tree_next_chunk(struct radix_tree_root *root, 
	/* Update the iterator state */

	iter->index = (index &~ node_maxindex(node)) | (offset << node->shift);

	iter->next_index = (index | node_maxindex(node)) + 1;

	__set_iter_shift(iter, shift);

	__set_iter_shift(iter, node->shift);



	/* Construct iter->tags bit-mask from node->tags[tag] array */

	if (flags & RADIX_TREE_ITER_TAGGED) {
@@ -1010,10 +993,10 @@ unsigned long radix_tree_range_tag_if_tagged(struct radix_tree_root *root, 
{

	struct radix_tree_node *parent, *node, *child;

	unsigned long maxindex;

	unsigned int shift = radix_tree_load_root(root, &child, &maxindex);

	unsigned long tagged = 0;

	unsigned long index = *first_indexp;



	radix_tree_load_root(root, &child, &maxindex);

	last_index = min(last_index, maxindex);

	if (index > last_index)

		return 0;
@@ -1030,11 +1013,9 @@ unsigned long radix_tree_range_tag_if_tagged(struct radix_tree_root *root, 
	}



	node = entry_to_node(child);

	shift -= RADIX_TREE_MAP_SHIFT;



	for (;;) {

		unsigned offset = (index >> shift) & RADIX_TREE_MAP_MASK;

		offset = radix_tree_descend(node, &child, offset);

		unsigned offset = radix_tree_descend(node, &child, index);

		if (!child)

			goto next;

		if (!tag_get(node, iftag, offset))
@@ -1042,7 +1023,6 @@ unsigned long radix_tree_range_tag_if_tagged(struct radix_tree_root *root, 
		/* Sibling slots never have tags set on them */

		if (radix_tree_is_internal_node(child)) {

			node = entry_to_node(child);

			shift -= RADIX_TREE_MAP_SHIFT;

			continue;

		}
@@ -1063,12 +1043,12 @@ unsigned long radix_tree_range_tag_if_tagged(struct radix_tree_root *root, 
			tag_set(parent, settag, offset);

		}

 next:

		/* Go to next item at level determined by 'shift' */

		index = ((index >> shift) + 1) << shift;

		/* Go to next entry in node */

		index = ((index >> node->shift) + 1) << node->shift;

		/* Overflow can happen when last_index is ~0UL... */

		if (index > last_index || !index)

			break;

		offset = (index >> shift) & RADIX_TREE_MAP_MASK;

		offset = (index >> node->shift) & RADIX_TREE_MAP_MASK;

		while (offset == 0) {

			/*

			 * We've fully scanned this node. Go up. Because
@@ -1076,8 +1056,7 @@ unsigned long radix_tree_range_tag_if_tagged(struct radix_tree_root *root, 
			 * we do below cannot wander astray.

			 */

			node = node->parent;

			shift += RADIX_TREE_MAP_SHIFT;

			offset = (index >> shift) & RADIX_TREE_MAP_MASK;

			offset = (index >> node->shift) & RADIX_TREE_MAP_MASK;

		}

		if (is_sibling_entry(node, node->slots[offset]))

			goto next;
@@ -1275,13 +1254,10 @@ struct locate_info { 
static unsigned long __locate(struct radix_tree_node *slot, void *item,

			      unsigned long index, struct locate_info *info)

{

	unsigned int shift;

	unsigned long i;



	shift = slot->shift + RADIX_TREE_MAP_SHIFT;



	do {

		shift -= RADIX_TREE_MAP_SHIFT;

		unsigned int shift = slot->shift;



		for (i = (index >> shift) & RADIX_TREE_MAP_MASK;

		     i < RADIX_TREE_MAP_SIZE;
@@ -1304,9 +1280,7 @@ static unsigned long __locate(struct radix_tree_node *slot, void *item, 
			slot = node;

			break;

		}

		if (i == RADIX_TREE_MAP_SIZE)

			break;

	} while (shift);

	} while (i < RADIX_TREE_MAP_SIZE);



out:

	if ((index == 0) && (i == RADIX_TREE_MAP_SIZE))

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