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: Matthew Wilcox <willy@linux.intel.com>
Reviewed-by: Ross 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: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/lib/radix-tree.c b/lib/radix-tree.c
index dd04b51..648da908 100644
--- a/lib/radix-tree.c
+++ b/lib/radix-tree.c
@@ -223,10 +223,10 @@
{
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 @@
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 @@
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 @@
}
/* 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 @@
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 @@
{
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 @@
}
}
- 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 @@
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 @@
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;