From 0a2efc6c809b01872321d9c7e7d82d59ac6fde10 Mon Sep 17 00:00:00 2001 From: Matthew Wilcox Date: Fri, 20 May 2016 17:02:46 -0700 Subject: [PATCH] radix-tree: rewrite radix_tree_locate_item Use the new multi-order support functions to rewrite radix_tree_locate_item(). Modify the locate tests to test multiorder entries too. [hughd@google.com: radix_tree_locate_item() is often returning the wrong index] Link: http://lkml.kernel.org/r/alpine.LSU.2.11.1605012108490.1166@eggly.anvils Signed-off-by: Matthew Wilcox Reviewed-by: Ross Zwisler Cc: Konstantin Khlebnikov Cc: Kirill Shutemov Cc: Jan Kara Cc: Neil Brown Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- lib/radix-tree.c | 87 ++++++++++++++++++++--------------------- tools/testing/radix-tree/main.c | 30 ++++++++------ 2 files changed, 61 insertions(+), 56 deletions(-) diff --git a/lib/radix-tree.c b/lib/radix-tree.c index 9b5d8a9..8329a2e 100644 --- a/lib/radix-tree.c +++ b/lib/radix-tree.c @@ -1303,58 +1303,54 @@ EXPORT_SYMBOL(radix_tree_gang_lookup_tag_slot); #if defined(CONFIG_SHMEM) && defined(CONFIG_SWAP) #include /* for cond_resched() */ +struct locate_info { + unsigned long found_index; + bool stop; +}; + /* * This linear search is at present only useful to shmem_unuse_inode(). */ static unsigned long __locate(struct radix_tree_node *slot, void *item, - unsigned long index, unsigned long *found_index) + unsigned long index, struct locate_info *info) { unsigned int shift, height; unsigned long i; height = slot->path & RADIX_TREE_HEIGHT_MASK; - shift = (height-1) * RADIX_TREE_MAP_SHIFT; + shift = height * 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; - } + do { + shift -= RADIX_TREE_MAP_SHIFT; - slot = rcu_dereference_raw(slot->slots[i]); - if (slot == NULL) - goto out; - if (!radix_tree_is_indirect_ptr(slot)) { - if (slot == item) { - *found_index = index + i; - index = 0; - } else { - index += shift; + for (i = (index >> shift) & RADIX_TREE_MAP_MASK; + i < RADIX_TREE_MAP_SIZE; + i++, index += (1UL << shift)) { + struct radix_tree_node *node = + rcu_dereference_raw(slot->slots[i]); + if (node == RADIX_TREE_RETRY) + goto out; + if (!radix_tree_is_indirect_ptr(node)) { + if (node == item) { + info->found_index = index; + info->stop = true; + goto out; + } + continue; } - goto out; + node = indirect_to_ptr(node); + if (is_sibling_entry(slot, node)) + continue; + slot = node; + break; } - slot = indirect_to_ptr(slot); - shift -= RADIX_TREE_MAP_SHIFT; - } + if (i == RADIX_TREE_MAP_SIZE) + break; + } while (shift); - /* Bottom level: check items */ - for (i = 0; i < RADIX_TREE_MAP_SIZE; i++) { - if (slot->slots[i] == item) { - *found_index = index + i; - index = 0; - goto out; - } - } - index += RADIX_TREE_MAP_SIZE; out: + if ((index == 0) && (i == RADIX_TREE_MAP_SIZE)) + info->stop = true; return index; } @@ -1372,7 +1368,10 @@ unsigned long radix_tree_locate_item(struct radix_tree_root *root, void *item) struct radix_tree_node *node; unsigned long max_index; unsigned long cur_index = 0; - unsigned long found_index = -1; + struct locate_info info = { + .found_index = -1, + .stop = false, + }; do { rcu_read_lock(); @@ -1380,24 +1379,24 @@ unsigned long radix_tree_locate_item(struct radix_tree_root *root, void *item) if (!radix_tree_is_indirect_ptr(node)) { rcu_read_unlock(); if (node == item) - found_index = 0; + info.found_index = 0; break; } node = indirect_to_ptr(node); - max_index = radix_tree_maxindex(node->path & - RADIX_TREE_HEIGHT_MASK); + + max_index = node_maxindex(node); if (cur_index > max_index) { rcu_read_unlock(); break; } - cur_index = __locate(node, item, cur_index, &found_index); + cur_index = __locate(node, item, cur_index, &info); rcu_read_unlock(); cond_resched(); - } while (cur_index != 0 && cur_index <= max_index); + } while (!info.stop && cur_index <= max_index); - return found_index; + return info.found_index; } #else unsigned long radix_tree_locate_item(struct radix_tree_root *root, void *item) diff --git a/tools/testing/radix-tree/main.c b/tools/testing/radix-tree/main.c index b6a700b..65231e9 100644 --- a/tools/testing/radix-tree/main.c +++ b/tools/testing/radix-tree/main.c @@ -232,17 +232,18 @@ void copy_tag_check(void) item_kill_tree(&tree); } -void __locate_check(struct radix_tree_root *tree, unsigned long index) +void __locate_check(struct radix_tree_root *tree, unsigned long index, + unsigned order) { struct item *item; unsigned long index2; - item_insert(tree, index); + item_insert_order(tree, index, order); item = item_lookup(tree, index); index2 = radix_tree_locate_item(tree, item); if (index != index2) { - printf("index %ld inserted; found %ld\n", - index, index2); + printf("index %ld order %d inserted; found %ld\n", + index, order, index2); abort(); } } @@ -250,21 +251,26 @@ void __locate_check(struct radix_tree_root *tree, unsigned long index) static void locate_check(void) { RADIX_TREE(tree, GFP_KERNEL); + unsigned order; unsigned long offset, index; - for (offset = 0; offset < (1 << 3); offset++) { - for (index = 0; index < (1UL << 5); index++) { - __locate_check(&tree, index + offset); - } - if (radix_tree_locate_item(&tree, &tree) != -1) - abort(); + for (order = 0; order < 20; order++) { + for (offset = 0; offset < (1 << (order + 3)); + offset += (1UL << order)) { + for (index = 0; index < (1UL << (order + 5)); + index += (1UL << order)) { + __locate_check(&tree, index + offset, order); + } + if (radix_tree_locate_item(&tree, &tree) != -1) + abort(); - item_kill_tree(&tree); + item_kill_tree(&tree); + } } if (radix_tree_locate_item(&tree, &tree) != -1) abort(); - __locate_check(&tree, -1); + __locate_check(&tree, -1, 0); if (radix_tree_locate_item(&tree, &tree) != -1) abort(); item_kill_tree(&tree); -- 2.7.4