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: Matthew 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: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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d604c32452
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9e85d81119
1 changed files with 26 additions and 52 deletions
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@ -94,9 +94,10 @@ static inline unsigned long get_slot_offset(struct radix_tree_node *parent,
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return slot - parent->slots;
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}
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static unsigned radix_tree_descend(struct radix_tree_node *parent,
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struct radix_tree_node **nodep, unsigned offset)
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static unsigned int radix_tree_descend(struct radix_tree_node *parent,
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struct radix_tree_node **nodep, unsigned long index)
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{
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unsigned int offset = (index >> parent->shift) & RADIX_TREE_MAP_MASK;
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void **entry = rcu_dereference_raw(parent->slots[offset]);
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#ifdef CONFIG_RADIX_TREE_MULTIORDER
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@ -536,8 +537,7 @@ int __radix_tree_create(struct radix_tree_root *root, unsigned long index,
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/* Go a level down */
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node = entry_to_node(child);
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offset = (index >> shift) & RADIX_TREE_MAP_MASK;
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offset = radix_tree_descend(node, &child, offset);
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offset = radix_tree_descend(node, &child, index);
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slot = &node->slots[offset];
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}
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@ -625,13 +625,12 @@ void *__radix_tree_lookup(struct radix_tree_root *root, unsigned long index,
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{
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struct radix_tree_node *node, *parent;
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unsigned long maxindex;
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unsigned int shift;
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void **slot;
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restart:
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parent = NULL;
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slot = (void **)&root->rnode;
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shift = radix_tree_load_root(root, &node, &maxindex);
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radix_tree_load_root(root, &node, &maxindex);
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if (index > maxindex)
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return NULL;
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@ -641,9 +640,7 @@ void *__radix_tree_lookup(struct radix_tree_root *root, unsigned long index,
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if (node == RADIX_TREE_RETRY)
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goto restart;
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parent = entry_to_node(node);
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shift -= RADIX_TREE_MAP_SHIFT;
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offset = (index >> shift) & RADIX_TREE_MAP_MASK;
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offset = radix_tree_descend(parent, &node, offset);
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offset = radix_tree_descend(parent, &node, index);
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slot = parent->slots + offset;
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}
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@ -713,19 +710,15 @@ void *radix_tree_tag_set(struct radix_tree_root *root,
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{
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struct radix_tree_node *node, *parent;
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unsigned long maxindex;
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unsigned int shift;
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shift = radix_tree_load_root(root, &node, &maxindex);
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radix_tree_load_root(root, &node, &maxindex);
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BUG_ON(index > maxindex);
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while (radix_tree_is_internal_node(node)) {
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unsigned offset;
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shift -= RADIX_TREE_MAP_SHIFT;
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offset = (index >> shift) & RADIX_TREE_MAP_MASK;
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parent = entry_to_node(node);
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offset = radix_tree_descend(parent, &node, offset);
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offset = radix_tree_descend(parent, &node, index);
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BUG_ON(!node);
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if (!tag_get(parent, tag, offset))
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@ -779,21 +772,17 @@ void *radix_tree_tag_clear(struct radix_tree_root *root,
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{
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struct radix_tree_node *node, *parent;
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unsigned long maxindex;
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unsigned int shift;
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int uninitialized_var(offset);
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shift = radix_tree_load_root(root, &node, &maxindex);
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radix_tree_load_root(root, &node, &maxindex);
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if (index > maxindex)
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return NULL;
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parent = NULL;
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while (radix_tree_is_internal_node(node)) {
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shift -= RADIX_TREE_MAP_SHIFT;
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offset = (index >> shift) & RADIX_TREE_MAP_MASK;
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parent = entry_to_node(node);
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offset = radix_tree_descend(parent, &node, offset);
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offset = radix_tree_descend(parent, &node, index);
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}
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if (node)
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@ -823,25 +812,21 @@ int radix_tree_tag_get(struct radix_tree_root *root,
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{
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struct radix_tree_node *node, *parent;
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unsigned long maxindex;
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unsigned int shift;
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if (!root_tag_get(root, tag))
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return 0;
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shift = radix_tree_load_root(root, &node, &maxindex);
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radix_tree_load_root(root, &node, &maxindex);
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if (index > maxindex)
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return 0;
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if (node == NULL)
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return 0;
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while (radix_tree_is_internal_node(node)) {
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int offset;
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shift -= RADIX_TREE_MAP_SHIFT;
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offset = (index >> shift) & RADIX_TREE_MAP_MASK;
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unsigned offset;
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parent = entry_to_node(node);
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offset = radix_tree_descend(parent, &node, offset);
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offset = radix_tree_descend(parent, &node, index);
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if (!node)
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return 0;
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@ -874,7 +859,7 @@ static inline void __set_iter_shift(struct radix_tree_iter *iter,
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void **radix_tree_next_chunk(struct radix_tree_root *root,
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struct radix_tree_iter *iter, unsigned flags)
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{
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unsigned shift, tag = flags & RADIX_TREE_ITER_TAG_MASK;
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unsigned tag = flags & RADIX_TREE_ITER_TAG_MASK;
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struct radix_tree_node *node, *child;
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unsigned long index, offset, maxindex;
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@ -895,7 +880,7 @@ void **radix_tree_next_chunk(struct radix_tree_root *root,
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return NULL;
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restart:
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shift = radix_tree_load_root(root, &child, &maxindex);
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radix_tree_load_root(root, &child, &maxindex);
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if (index > maxindex)
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return NULL;
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if (!child)
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@ -912,9 +897,7 @@ void **radix_tree_next_chunk(struct radix_tree_root *root,
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do {
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node = entry_to_node(child);
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shift -= RADIX_TREE_MAP_SHIFT;
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offset = (index >> shift) & RADIX_TREE_MAP_MASK;
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offset = radix_tree_descend(node, &child, offset);
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offset = radix_tree_descend(node, &child, index);
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if ((flags & RADIX_TREE_ITER_TAGGED) ?
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!tag_get(node, tag, offset) : !child) {
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@ -936,7 +919,7 @@ void **radix_tree_next_chunk(struct radix_tree_root *root,
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break;
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}
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index &= ~node_maxindex(node);
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index += offset << shift;
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index += offset << node->shift;
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/* Overflow after ~0UL */
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if (!index)
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return NULL;
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@ -952,7 +935,7 @@ void **radix_tree_next_chunk(struct radix_tree_root *root,
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/* Update the iterator state */
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iter->index = (index &~ node_maxindex(node)) | (offset << node->shift);
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iter->next_index = (index | node_maxindex(node)) + 1;
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__set_iter_shift(iter, shift);
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__set_iter_shift(iter, node->shift);
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/* Construct iter->tags bit-mask from node->tags[tag] array */
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if (flags & RADIX_TREE_ITER_TAGGED) {
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@ -1010,10 +993,10 @@ unsigned long radix_tree_range_tag_if_tagged(struct radix_tree_root *root,
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{
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struct radix_tree_node *parent, *node, *child;
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unsigned long maxindex;
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unsigned int shift = radix_tree_load_root(root, &child, &maxindex);
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unsigned long tagged = 0;
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unsigned long index = *first_indexp;
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radix_tree_load_root(root, &child, &maxindex);
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last_index = min(last_index, maxindex);
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if (index > last_index)
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return 0;
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@ -1030,11 +1013,9 @@ unsigned long radix_tree_range_tag_if_tagged(struct radix_tree_root *root,
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}
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node = entry_to_node(child);
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shift -= RADIX_TREE_MAP_SHIFT;
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for (;;) {
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unsigned offset = (index >> shift) & RADIX_TREE_MAP_MASK;
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offset = radix_tree_descend(node, &child, offset);
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unsigned offset = radix_tree_descend(node, &child, index);
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if (!child)
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goto next;
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if (!tag_get(node, iftag, offset))
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@ -1042,7 +1023,6 @@ unsigned long radix_tree_range_tag_if_tagged(struct radix_tree_root *root,
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/* Sibling slots never have tags set on them */
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if (radix_tree_is_internal_node(child)) {
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node = entry_to_node(child);
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shift -= RADIX_TREE_MAP_SHIFT;
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continue;
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}
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@ -1063,12 +1043,12 @@ unsigned long radix_tree_range_tag_if_tagged(struct radix_tree_root *root,
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tag_set(parent, settag, offset);
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}
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next:
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/* Go to next item at level determined by 'shift' */
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index = ((index >> shift) + 1) << shift;
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/* Go to next entry in node */
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index = ((index >> node->shift) + 1) << node->shift;
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/* Overflow can happen when last_index is ~0UL... */
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if (index > last_index || !index)
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break;
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offset = (index >> shift) & RADIX_TREE_MAP_MASK;
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offset = (index >> node->shift) & RADIX_TREE_MAP_MASK;
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while (offset == 0) {
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/*
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* We've fully scanned this node. Go up. Because
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@ -1076,8 +1056,7 @@ unsigned long radix_tree_range_tag_if_tagged(struct radix_tree_root *root,
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* we do below cannot wander astray.
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*/
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node = node->parent;
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shift += RADIX_TREE_MAP_SHIFT;
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offset = (index >> shift) & RADIX_TREE_MAP_MASK;
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offset = (index >> node->shift) & RADIX_TREE_MAP_MASK;
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}
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if (is_sibling_entry(node, node->slots[offset]))
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goto next;
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@ -1275,13 +1254,10 @@ struct locate_info {
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static unsigned long __locate(struct radix_tree_node *slot, void *item,
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unsigned long index, struct locate_info *info)
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{
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unsigned int shift;
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unsigned long i;
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shift = slot->shift + RADIX_TREE_MAP_SHIFT;
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do {
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shift -= RADIX_TREE_MAP_SHIFT;
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unsigned int shift = slot->shift;
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for (i = (index >> shift) & RADIX_TREE_MAP_MASK;
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i < RADIX_TREE_MAP_SIZE;
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@ -1304,9 +1280,7 @@ static unsigned long __locate(struct radix_tree_node *slot, void *item,
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slot = node;
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break;
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}
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if (i == RADIX_TREE_MAP_SIZE)
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break;
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} while (shift);
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} while (i < RADIX_TREE_MAP_SIZE);
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out:
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if ((index == 0) && (i == RADIX_TREE_MAP_SIZE))
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