Commit c12e51b0 authored by Matthew Wilcox's avatar Matthew Wilcox Committed by Linus Torvalds
Browse files

radix-tree: replace node->height with node->shift 



node->shift represents the shift necessary for looking in the slots
array at this level.  It is equal to the old (node->height - 1) *
RADIX_TREE_MAP_SHIFT.

Signed-off-by: default avatarMatthew Wilcox <willy@linux.intel.com>
Reviewed-by: default avatarRoss Zwisler <ross.zwisler@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>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 0c7fa0a8

include/linux/radix-tree.h

+1 −1
Original line number Diff line number Diff line
@@ -89,7 +89,7 @@ static inline int radix_tree_is_indirect_ptr(void *ptr) 
#define RADIX_TREE_COUNT_MASK	((1UL << RADIX_TREE_COUNT_SHIFT) - 1)



struct radix_tree_node {

	unsigned char	height;	/* From the bottom */

	unsigned char	shift;	/* Bits remaining in each slot */

	unsigned char	offset;	/* Slot offset in parent */

	unsigned int	count;

	union {

lib/radix-tree.c

+16 −14
Original line number Diff line number Diff line
@@ -223,10 +223,10 @@ static void dump_node(struct radix_tree_node *node, 
{

	unsigned long i;



	pr_debug("radix node: %p offset %d tags %lx %lx %lx height %d count %d parent %p\n",

	pr_debug("radix node: %p offset %d tags %lx %lx %lx shift %d count %d parent %p\n",

		node, node->offset,

		node->tags[0][0], node->tags[1][0], node->tags[2][0],

		node->height, node->count, node->parent);

		node->shift, node->count, node->parent);



	for (i = 0; i < RADIX_TREE_MAP_SIZE; i++) {

		unsigned long first = index | (i << shift);
@@ -419,9 +419,14 @@ static inline unsigned long radix_tree_maxindex(unsigned int height) 
	return height_to_maxindex[height];

}



static inline unsigned long shift_maxindex(unsigned int shift)

{

	return (RADIX_TREE_MAP_SIZE << shift) - 1;

}



static inline unsigned long node_maxindex(struct radix_tree_node *node)

{

	return radix_tree_maxindex(node->height);

	return shift_maxindex(node->shift);

}



static unsigned radix_tree_load_root(struct radix_tree_root *root,
@@ -434,7 +439,7 @@ static unsigned radix_tree_load_root(struct radix_tree_root *root, 
	if (likely(radix_tree_is_indirect_ptr(node))) {

		node = indirect_to_ptr(node);

		*maxindex = node_maxindex(node);

		return node->height * RADIX_TREE_MAP_SHIFT;

		return node->shift + RADIX_TREE_MAP_SHIFT;

	}



	*maxindex = 0;
@@ -475,9 +480,9 @@ static int radix_tree_extend(struct radix_tree_root *root, 
		}



		/* Increase the height.  */

		newheight = root->height + 1;

		newheight = root->height;

		BUG_ON(newheight > BITS_PER_LONG);

		node->height = newheight;

		node->shift = newheight * RADIX_TREE_MAP_SHIFT;

		node->offset = 0;

		node->count = 1;

		node->parent = NULL;
@@ -490,7 +495,7 @@ static int radix_tree_extend(struct radix_tree_root *root, 
		node->slots[0] = slot;

		node = ptr_to_indirect(node);

		rcu_assign_pointer(root->rnode, node);

		root->height = newheight;

		root->height = ++newheight;

	} while (height > root->height);

out:

	return height * RADIX_TREE_MAP_SHIFT;
@@ -519,7 +524,7 @@ int __radix_tree_create(struct radix_tree_root *root, unsigned long index, 
{

	struct radix_tree_node *node = NULL, *slot;

	unsigned long maxindex;

	unsigned int height, shift, offset;

	unsigned int shift, offset;

	unsigned long max = index | ((1UL << order) - 1);



	shift = radix_tree_load_root(root, &slot, &maxindex);
@@ -537,16 +542,15 @@ int __radix_tree_create(struct radix_tree_root *root, unsigned long index, 
		}

	}



	height = root->height;



	offset = 0;			/* uninitialised var warning */

	while (shift > order) {

		shift -= RADIX_TREE_MAP_SHIFT;

		if (slot == NULL) {

			/* Have to add a child node.  */

			slot = radix_tree_node_alloc(root);

			if (!slot)

				return -ENOMEM;

			slot->height = height;

			slot->shift = shift;

			slot->offset = offset;

			slot->parent = node;

			if (node) {
@@ -560,8 +564,6 @@ int __radix_tree_create(struct radix_tree_root *root, unsigned long index, 
			break;



		/* Go a level down */

		height--;

		shift -= RADIX_TREE_MAP_SHIFT;

		node = indirect_to_ptr(slot);

		offset = (index >> shift) & RADIX_TREE_MAP_MASK;

		offset = radix_tree_descend(node, &slot, offset);
@@ -1322,7 +1324,7 @@ static unsigned long __locate(struct radix_tree_node *slot, void *item, 
	unsigned int shift;

	unsigned long i;



	shift = slot->height * RADIX_TREE_MAP_SHIFT;

	shift = slot->shift + RADIX_TREE_MAP_SHIFT;



	do {

		shift -= RADIX_TREE_MAP_SHIFT;

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