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radix-tree: rewrite gang lookup using iterator
Rewrite radix_tree_gang_lookup_* functions using the new radix-tree iterator. Signed-off-by: Konstantin Khlebnikov <khlebnikov@openvz.org> Tested-by: Hugh Dickins <hughd@google.com> Cc: Christoph Hellwig <hch@lst.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Konstantin Khlebnikov
Linus Torvalds
parent
78c1d78488
commit
cebbd29e1c
1 changed files with 33 additions and 258 deletions
291
lib/radix-tree.c
291
lib/radix-tree.c
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@ -968,57 +968,6 @@ unsigned long radix_tree_prev_hole(struct radix_tree_root *root,
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}
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EXPORT_SYMBOL(radix_tree_prev_hole);
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static unsigned int
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__lookup(struct radix_tree_node *slot, void ***results, unsigned long *indices,
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unsigned long index, unsigned int max_items, unsigned long *next_index)
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{
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unsigned int nr_found = 0;
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unsigned int shift, height;
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unsigned long i;
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height = slot->height;
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if (height == 0)
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goto out;
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shift = (height-1) * RADIX_TREE_MAP_SHIFT;
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for ( ; height > 1; height--) {
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i = (index >> shift) & RADIX_TREE_MAP_MASK;
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for (;;) {
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if (slot->slots[i] != NULL)
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break;
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index &= ~((1UL << shift) - 1);
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index += 1UL << shift;
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if (index == 0)
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goto out; /* 32-bit wraparound */
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i++;
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if (i == RADIX_TREE_MAP_SIZE)
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goto out;
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}
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shift -= RADIX_TREE_MAP_SHIFT;
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slot = rcu_dereference_raw(slot->slots[i]);
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if (slot == NULL)
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goto out;
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}
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/* Bottom level: grab some items */
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for (i = index & RADIX_TREE_MAP_MASK; i < RADIX_TREE_MAP_SIZE; i++) {
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if (slot->slots[i]) {
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results[nr_found] = &(slot->slots[i]);
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if (indices)
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indices[nr_found] = index;
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if (++nr_found == max_items) {
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index++;
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goto out;
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}
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}
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index++;
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}
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out:
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*next_index = index;
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return nr_found;
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}
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/**
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* radix_tree_gang_lookup - perform multiple lookup on a radix tree
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* @root: radix tree root
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@ -1042,48 +991,19 @@ unsigned int
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radix_tree_gang_lookup(struct radix_tree_root *root, void **results,
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unsigned long first_index, unsigned int max_items)
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{
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unsigned long max_index;
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struct radix_tree_node *node;
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unsigned long cur_index = first_index;
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unsigned int ret;
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struct radix_tree_iter iter;
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void **slot;
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unsigned int ret = 0;
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node = rcu_dereference_raw(root->rnode);
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if (!node)
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if (unlikely(!max_items))
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return 0;
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if (!radix_tree_is_indirect_ptr(node)) {
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if (first_index > 0)
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return 0;
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results[0] = node;
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return 1;
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}
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node = indirect_to_ptr(node);
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max_index = radix_tree_maxindex(node->height);
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ret = 0;
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while (ret < max_items) {
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unsigned int nr_found, slots_found, i;
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unsigned long next_index; /* Index of next search */
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if (cur_index > max_index)
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radix_tree_for_each_slot(slot, root, &iter, first_index) {
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results[ret] = indirect_to_ptr(rcu_dereference_raw(*slot));
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if (!results[ret])
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continue;
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if (++ret == max_items)
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break;
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slots_found = __lookup(node, (void ***)results + ret, NULL,
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cur_index, max_items - ret, &next_index);
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nr_found = 0;
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for (i = 0; i < slots_found; i++) {
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struct radix_tree_node *slot;
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slot = *(((void ***)results)[ret + i]);
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if (!slot)
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continue;
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results[ret + nr_found] =
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indirect_to_ptr(rcu_dereference_raw(slot));
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nr_found++;
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}
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ret += nr_found;
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if (next_index == 0)
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break;
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cur_index = next_index;
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}
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return ret;
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@ -1113,112 +1033,25 @@ radix_tree_gang_lookup_slot(struct radix_tree_root *root,
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void ***results, unsigned long *indices,
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unsigned long first_index, unsigned int max_items)
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{
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unsigned long max_index;
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struct radix_tree_node *node;
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unsigned long cur_index = first_index;
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unsigned int ret;
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struct radix_tree_iter iter;
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void **slot;
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unsigned int ret = 0;
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node = rcu_dereference_raw(root->rnode);
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if (!node)
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if (unlikely(!max_items))
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return 0;
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if (!radix_tree_is_indirect_ptr(node)) {
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if (first_index > 0)
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return 0;
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results[0] = (void **)&root->rnode;
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radix_tree_for_each_slot(slot, root, &iter, first_index) {
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results[ret] = slot;
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if (indices)
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indices[0] = 0;
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return 1;
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}
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node = indirect_to_ptr(node);
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max_index = radix_tree_maxindex(node->height);
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ret = 0;
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while (ret < max_items) {
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unsigned int slots_found;
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unsigned long next_index; /* Index of next search */
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if (cur_index > max_index)
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indices[ret] = iter.index;
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if (++ret == max_items)
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break;
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slots_found = __lookup(node, results + ret,
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indices ? indices + ret : NULL,
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cur_index, max_items - ret, &next_index);
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ret += slots_found;
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if (next_index == 0)
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break;
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cur_index = next_index;
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}
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return ret;
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}
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EXPORT_SYMBOL(radix_tree_gang_lookup_slot);
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/*
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* FIXME: the two tag_get()s here should use find_next_bit() instead of
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* open-coding the search.
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*/
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static unsigned int
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__lookup_tag(struct radix_tree_node *slot, void ***results, unsigned long index,
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unsigned int max_items, unsigned long *next_index, unsigned int tag)
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{
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unsigned int nr_found = 0;
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unsigned int shift, height;
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height = slot->height;
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if (height == 0)
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goto out;
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shift = (height-1) * RADIX_TREE_MAP_SHIFT;
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while (height > 0) {
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unsigned long i = (index >> shift) & RADIX_TREE_MAP_MASK ;
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for (;;) {
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if (tag_get(slot, tag, i))
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break;
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index &= ~((1UL << shift) - 1);
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index += 1UL << shift;
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if (index == 0)
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goto out; /* 32-bit wraparound */
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i++;
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if (i == RADIX_TREE_MAP_SIZE)
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goto out;
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}
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height--;
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if (height == 0) { /* Bottom level: grab some items */
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unsigned long j = index & RADIX_TREE_MAP_MASK;
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for ( ; j < RADIX_TREE_MAP_SIZE; j++) {
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index++;
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if (!tag_get(slot, tag, j))
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continue;
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/*
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* Even though the tag was found set, we need to
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* recheck that we have a non-NULL node, because
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* if this lookup is lockless, it may have been
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* subsequently deleted.
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*
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* Similar care must be taken in any place that
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* lookup ->slots[x] without a lock (ie. can't
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* rely on its value remaining the same).
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*/
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if (slot->slots[j]) {
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results[nr_found++] = &(slot->slots[j]);
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if (nr_found == max_items)
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goto out;
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}
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}
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}
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shift -= RADIX_TREE_MAP_SHIFT;
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slot = rcu_dereference_raw(slot->slots[i]);
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if (slot == NULL)
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break;
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}
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out:
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*next_index = index;
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return nr_found;
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}
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/**
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* radix_tree_gang_lookup_tag - perform multiple lookup on a radix tree
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* based on a tag
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@ -1237,52 +1070,19 @@ radix_tree_gang_lookup_tag(struct radix_tree_root *root, void **results,
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unsigned long first_index, unsigned int max_items,
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unsigned int tag)
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{
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struct radix_tree_node *node;
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unsigned long max_index;
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unsigned long cur_index = first_index;
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unsigned int ret;
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struct radix_tree_iter iter;
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void **slot;
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unsigned int ret = 0;
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/* check the root's tag bit */
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if (!root_tag_get(root, tag))
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if (unlikely(!max_items))
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return 0;
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node = rcu_dereference_raw(root->rnode);
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if (!node)
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return 0;
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if (!radix_tree_is_indirect_ptr(node)) {
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if (first_index > 0)
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return 0;
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results[0] = node;
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return 1;
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}
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node = indirect_to_ptr(node);
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max_index = radix_tree_maxindex(node->height);
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ret = 0;
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while (ret < max_items) {
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unsigned int nr_found, slots_found, i;
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unsigned long next_index; /* Index of next search */
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if (cur_index > max_index)
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radix_tree_for_each_tagged(slot, root, &iter, first_index, tag) {
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results[ret] = indirect_to_ptr(rcu_dereference_raw(*slot));
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if (!results[ret])
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continue;
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if (++ret == max_items)
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break;
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slots_found = __lookup_tag(node, (void ***)results + ret,
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cur_index, max_items - ret, &next_index, tag);
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nr_found = 0;
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for (i = 0; i < slots_found; i++) {
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struct radix_tree_node *slot;
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slot = *(((void ***)results)[ret + i]);
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if (!slot)
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continue;
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results[ret + nr_found] =
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indirect_to_ptr(rcu_dereference_raw(slot));
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nr_found++;
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}
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ret += nr_found;
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if (next_index == 0)
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break;
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cur_index = next_index;
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}
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return ret;
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@ -1307,42 +1107,17 @@ radix_tree_gang_lookup_tag_slot(struct radix_tree_root *root, void ***results,
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unsigned long first_index, unsigned int max_items,
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unsigned int tag)
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{
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struct radix_tree_node *node;
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unsigned long max_index;
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unsigned long cur_index = first_index;
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unsigned int ret;
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struct radix_tree_iter iter;
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void **slot;
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unsigned int ret = 0;
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/* check the root's tag bit */
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if (!root_tag_get(root, tag))
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if (unlikely(!max_items))
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return 0;
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node = rcu_dereference_raw(root->rnode);
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if (!node)
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return 0;
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if (!radix_tree_is_indirect_ptr(node)) {
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if (first_index > 0)
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return 0;
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results[0] = (void **)&root->rnode;
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return 1;
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}
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node = indirect_to_ptr(node);
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max_index = radix_tree_maxindex(node->height);
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ret = 0;
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while (ret < max_items) {
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unsigned int slots_found;
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unsigned long next_index; /* Index of next search */
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if (cur_index > max_index)
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radix_tree_for_each_tagged(slot, root, &iter, first_index, tag) {
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results[ret] = slot;
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if (++ret == max_items)
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break;
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slots_found = __lookup_tag(node, results + ret,
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cur_index, max_items - ret, &next_index, tag);
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ret += slots_found;
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if (next_index == 0)
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break;
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cur_index = next_index;
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}
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return ret;
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