From cebbd29e1c2f7a969919f19f74583070840163d7 Mon Sep 17 00:00:00 2001 From: Konstantin Khlebnikov Date: Wed, 28 Mar 2012 14:42:53 -0700 Subject: radix-tree: rewrite gang lookup using iterator Rewrite radix_tree_gang_lookup_* functions using the new radix-tree iterator. Signed-off-by: Konstantin Khlebnikov Tested-by: Hugh Dickins Cc: Christoph Hellwig Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- lib/radix-tree.c | 291 +++++++------------------------------------------------ 1 file changed, 33 insertions(+), 258 deletions(-) (limited to 'lib') diff --git a/lib/radix-tree.c b/lib/radix-tree.c index fefa76e6ff96..86516f5588e3 100644 --- a/lib/radix-tree.c +++ b/lib/radix-tree.c @@ -968,57 +968,6 @@ unsigned long radix_tree_prev_hole(struct radix_tree_root *root, } EXPORT_SYMBOL(radix_tree_prev_hole); -static unsigned int -__lookup(struct radix_tree_node *slot, void ***results, unsigned long *indices, - unsigned long index, unsigned int max_items, unsigned long *next_index) -{ - unsigned int nr_found = 0; - unsigned int shift, height; - unsigned long i; - - height = slot->height; - if (height == 0) - goto out; - shift = (height-1) * RADIX_TREE_MAP_SHIFT; - - for ( ; height > 1; height--) { - i = (index >> shift) & RADIX_TREE_MAP_MASK; - for (;;) { - if (slot->slots[i] != NULL) - break; - index &= ~((1UL << shift) - 1); - index += 1UL << shift; - if (index == 0) - goto out; /* 32-bit wraparound */ - i++; - if (i == RADIX_TREE_MAP_SIZE) - goto out; - } - - shift -= RADIX_TREE_MAP_SHIFT; - slot = rcu_dereference_raw(slot->slots[i]); - if (slot == NULL) - goto out; - } - - /* Bottom level: grab some items */ - for (i = index & RADIX_TREE_MAP_MASK; i < RADIX_TREE_MAP_SIZE; i++) { - if (slot->slots[i]) { - results[nr_found] = &(slot->slots[i]); - if (indices) - indices[nr_found] = index; - if (++nr_found == max_items) { - index++; - goto out; - } - } - index++; - } -out: - *next_index = index; - return nr_found; -} - /** * radix_tree_gang_lookup - perform multiple lookup on a radix tree * @root: radix tree root @@ -1042,48 +991,19 @@ unsigned int radix_tree_gang_lookup(struct radix_tree_root *root, void **results, unsigned long first_index, unsigned int max_items) { - unsigned long max_index; - struct radix_tree_node *node; - unsigned long cur_index = first_index; - unsigned int ret; + struct radix_tree_iter iter; + void **slot; + unsigned int ret = 0; - node = rcu_dereference_raw(root->rnode); - if (!node) + if (unlikely(!max_items)) return 0; - if (!radix_tree_is_indirect_ptr(node)) { - if (first_index > 0) - return 0; - results[0] = node; - return 1; - } - node = indirect_to_ptr(node); - - max_index = radix_tree_maxindex(node->height); - - ret = 0; - while (ret < max_items) { - unsigned int nr_found, slots_found, i; - unsigned long next_index; /* Index of next search */ - - if (cur_index > max_index) - break; - slots_found = __lookup(node, (void ***)results + ret, NULL, - cur_index, max_items - ret, &next_index); - nr_found = 0; - for (i = 0; i < slots_found; i++) { - struct radix_tree_node *slot; - slot = *(((void ***)results)[ret + i]); - if (!slot) - continue; - results[ret + nr_found] = - indirect_to_ptr(rcu_dereference_raw(slot)); - nr_found++; - } - ret += nr_found; - if (next_index == 0) + radix_tree_for_each_slot(slot, root, &iter, first_index) { + results[ret] = indirect_to_ptr(rcu_dereference_raw(*slot)); + if (!results[ret]) + continue; + if (++ret == max_items) break; - cur_index = next_index; } return ret; @@ -1113,112 +1033,25 @@ radix_tree_gang_lookup_slot(struct radix_tree_root *root, void ***results, unsigned long *indices, unsigned long first_index, unsigned int max_items) { - unsigned long max_index; - struct radix_tree_node *node; - unsigned long cur_index = first_index; - unsigned int ret; + struct radix_tree_iter iter; + void **slot; + unsigned int ret = 0; - node = rcu_dereference_raw(root->rnode); - if (!node) + if (unlikely(!max_items)) return 0; - if (!radix_tree_is_indirect_ptr(node)) { - if (first_index > 0) - return 0; - results[0] = (void **)&root->rnode; + radix_tree_for_each_slot(slot, root, &iter, first_index) { + results[ret] = slot; if (indices) - indices[0] = 0; - return 1; - } - node = indirect_to_ptr(node); - - max_index = radix_tree_maxindex(node->height); - - ret = 0; - while (ret < max_items) { - unsigned int slots_found; - unsigned long next_index; /* Index of next search */ - - if (cur_index > max_index) + indices[ret] = iter.index; + if (++ret == max_items) break; - slots_found = __lookup(node, results + ret, - indices ? indices + ret : NULL, - cur_index, max_items - ret, &next_index); - ret += slots_found; - if (next_index == 0) - break; - cur_index = next_index; } return ret; } EXPORT_SYMBOL(radix_tree_gang_lookup_slot); -/* - * FIXME: the two tag_get()s here should use find_next_bit() instead of - * open-coding the search. - */ -static unsigned int -__lookup_tag(struct radix_tree_node *slot, void ***results, unsigned long index, - unsigned int max_items, unsigned long *next_index, unsigned int tag) -{ - unsigned int nr_found = 0; - unsigned int shift, height; - - height = slot->height; - if (height == 0) - goto out; - shift = (height-1) * RADIX_TREE_MAP_SHIFT; - - while (height > 0) { - unsigned long i = (index >> shift) & RADIX_TREE_MAP_MASK ; - - for (;;) { - if (tag_get(slot, tag, i)) - break; - index &= ~((1UL << shift) - 1); - index += 1UL << shift; - if (index == 0) - goto out; /* 32-bit wraparound */ - i++; - if (i == RADIX_TREE_MAP_SIZE) - goto out; - } - height--; - if (height == 0) { /* Bottom level: grab some items */ - unsigned long j = index & RADIX_TREE_MAP_MASK; - - for ( ; j < RADIX_TREE_MAP_SIZE; j++) { - index++; - if (!tag_get(slot, tag, j)) - continue; - /* - * Even though the tag was found set, we need to - * recheck that we have a non-NULL node, because - * if this lookup is lockless, it may have been - * subsequently deleted. - * - * Similar care must be taken in any place that - * lookup ->slots[x] without a lock (ie. can't - * rely on its value remaining the same). - */ - if (slot->slots[j]) { - results[nr_found++] = &(slot->slots[j]); - if (nr_found == max_items) - goto out; - } - } - } - shift -= RADIX_TREE_MAP_SHIFT; - slot = rcu_dereference_raw(slot->slots[i]); - if (slot == NULL) - break; - } -out: - *next_index = index; - return nr_found; -} - /** * radix_tree_gang_lookup_tag - perform multiple lookup on a radix tree * based on a tag @@ -1237,52 +1070,19 @@ radix_tree_gang_lookup_tag(struct radix_tree_root *root, void **results, unsigned long first_index, unsigned int max_items, unsigned int tag) { - struct radix_tree_node *node; - unsigned long max_index; - unsigned long cur_index = first_index; - unsigned int ret; + struct radix_tree_iter iter; + void **slot; + unsigned int ret = 0; - /* check the root's tag bit */ - if (!root_tag_get(root, tag)) + if (unlikely(!max_items)) return 0; - node = rcu_dereference_raw(root->rnode); - if (!node) - return 0; - - if (!radix_tree_is_indirect_ptr(node)) { - if (first_index > 0) - return 0; - results[0] = node; - return 1; - } - node = indirect_to_ptr(node); - - max_index = radix_tree_maxindex(node->height); - - ret = 0; - while (ret < max_items) { - unsigned int nr_found, slots_found, i; - unsigned long next_index; /* Index of next search */ - - if (cur_index > max_index) - break; - slots_found = __lookup_tag(node, (void ***)results + ret, - cur_index, max_items - ret, &next_index, tag); - nr_found = 0; - for (i = 0; i < slots_found; i++) { - struct radix_tree_node *slot; - slot = *(((void ***)results)[ret + i]); - if (!slot) - continue; - results[ret + nr_found] = - indirect_to_ptr(rcu_dereference_raw(slot)); - nr_found++; - } - ret += nr_found; - if (next_index == 0) + radix_tree_for_each_tagged(slot, root, &iter, first_index, tag) { + results[ret] = indirect_to_ptr(rcu_dereference_raw(*slot)); + if (!results[ret]) + continue; + if (++ret == max_items) break; - cur_index = next_index; } return ret; @@ -1307,42 +1107,17 @@ radix_tree_gang_lookup_tag_slot(struct radix_tree_root *root, void ***results, unsigned long first_index, unsigned int max_items, unsigned int tag) { - struct radix_tree_node *node; - unsigned long max_index; - unsigned long cur_index = first_index; - unsigned int ret; + struct radix_tree_iter iter; + void **slot; + unsigned int ret = 0; - /* check the root's tag bit */ - if (!root_tag_get(root, tag)) - return 0; - - node = rcu_dereference_raw(root->rnode); - if (!node) + if (unlikely(!max_items)) return 0; - if (!radix_tree_is_indirect_ptr(node)) { - if (first_index > 0) - return 0; - results[0] = (void **)&root->rnode; - return 1; - } - node = indirect_to_ptr(node); - - max_index = radix_tree_maxindex(node->height); - - ret = 0; - while (ret < max_items) { - unsigned int slots_found; - unsigned long next_index; /* Index of next search */ - - if (cur_index > max_index) - break; - slots_found = __lookup_tag(node, results + ret, - cur_index, max_items - ret, &next_index, tag); - ret += slots_found; - if (next_index == 0) + radix_tree_for_each_tagged(slot, root, &iter, first_index, tag) { + results[ret] = slot; + if (++ret == max_items) break; - cur_index = next_index; } return ret; -- cgit v1.2.3