From 339e6353046dd4f675304d696a88aefdd727298e Mon Sep 17 00:00:00 2001 From: Matthew Wilcox Date: Thu, 17 Mar 2016 14:21:48 -0700 Subject: [PATCH] radix_tree: tag all internal tree nodes as indirect pointers Set the 'indirect_ptr' bit on all the pointers to internal nodes, not just on the root node. This enables the following patches to support multi-order entries in the radix tree. This patch is split out for ease of bisection. Signed-off-by: Matthew Wilcox Cc: Johannes Weiner Cc: Matthew Wilcox Cc: "Kirill A. Shutemov" Cc: Ross Zwisler Cc: Hugh Dickins Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- lib/radix-tree.c | 24 ++++++++++++++++++------ tools/testing/radix-tree/test.c | 5 +++-- 2 files changed, 21 insertions(+), 8 deletions(-) diff --git a/lib/radix-tree.c b/lib/radix-tree.c index 224b369f5a5e..ff91792346f6 100644 --- a/lib/radix-tree.c +++ b/lib/radix-tree.c @@ -368,9 +368,10 @@ static int radix_tree_extend(struct radix_tree_root *root, unsigned long index) node->count = 1; node->parent = NULL; slot = root->rnode; - if (newheight > 1) { + if (radix_tree_is_indirect_ptr(slot) && newheight > 1) { slot = indirect_to_ptr(slot); slot->parent = node; + slot = ptr_to_indirect(slot); } node->slots[0] = slot; node = ptr_to_indirect(node); @@ -425,17 +426,20 @@ int __radix_tree_create(struct radix_tree_root *root, unsigned long index, slot->path = height; slot->parent = node; if (node) { - rcu_assign_pointer(node->slots[offset], slot); + rcu_assign_pointer(node->slots[offset], + ptr_to_indirect(slot)); node->count++; slot->path |= offset << RADIX_TREE_HEIGHT_SHIFT; } else - rcu_assign_pointer(root->rnode, ptr_to_indirect(slot)); + rcu_assign_pointer(root->rnode, + ptr_to_indirect(slot)); } /* Go a level down */ offset = (index >> shift) & RADIX_TREE_MAP_MASK; node = slot; slot = node->slots[offset]; + slot = indirect_to_ptr(slot); shift -= RADIX_TREE_MAP_SHIFT; height--; } @@ -533,6 +537,7 @@ void *__radix_tree_lookup(struct radix_tree_root *root, unsigned long index, node = rcu_dereference_raw(*slot); if (node == NULL) return NULL; + node = indirect_to_ptr(node); shift -= RADIX_TREE_MAP_SHIFT; height--; @@ -619,6 +624,7 @@ void *radix_tree_tag_set(struct radix_tree_root *root, tag_set(slot, tag, offset); slot = slot->slots[offset]; BUG_ON(slot == NULL); + slot = indirect_to_ptr(slot); shift -= RADIX_TREE_MAP_SHIFT; height--; } @@ -658,11 +664,12 @@ void *radix_tree_tag_clear(struct radix_tree_root *root, goto out; shift = height * RADIX_TREE_MAP_SHIFT; - slot = indirect_to_ptr(root->rnode); + slot = root->rnode; while (shift) { if (slot == NULL) goto out; + slot = indirect_to_ptr(slot); shift -= RADIX_TREE_MAP_SHIFT; offset = (index >> shift) & RADIX_TREE_MAP_MASK; @@ -738,6 +745,7 @@ int radix_tree_tag_get(struct radix_tree_root *root, if (node == NULL) return 0; + node = indirect_to_ptr(node); offset = (index >> shift) & RADIX_TREE_MAP_MASK; if (!tag_get(node, tag, offset)) @@ -838,6 +846,7 @@ restart: node = rcu_dereference_raw(node->slots[offset]); if (node == NULL) goto restart; + node = indirect_to_ptr(node); shift -= RADIX_TREE_MAP_SHIFT; offset = (index >> shift) & RADIX_TREE_MAP_MASK; } @@ -939,6 +948,7 @@ unsigned long radix_tree_range_tag_if_tagged(struct radix_tree_root *root, shift -= RADIX_TREE_MAP_SHIFT; node = slot; slot = slot->slots[offset]; + slot = indirect_to_ptr(slot); continue; } @@ -1195,6 +1205,7 @@ static unsigned long __locate(struct radix_tree_node *slot, void *item, slot = rcu_dereference_raw(slot->slots[i]); if (slot == NULL) goto out; + slot = indirect_to_ptr(slot); } /* Bottom level: check items */ @@ -1278,7 +1289,8 @@ static inline void radix_tree_shrink(struct radix_tree_root *root) */ if (to_free->count != 1) break; - if (!to_free->slots[0]) + slot = to_free->slots[0]; + if (!slot) break; /* @@ -1288,8 +1300,8 @@ static inline void radix_tree_shrink(struct radix_tree_root *root) * (to_free->slots[0]), it will be safe to dereference the new * one (root->rnode) as far as dependent read barriers go. */ - slot = to_free->slots[0]; if (root->height > 1) { + slot = indirect_to_ptr(slot); slot->parent = NULL; slot = ptr_to_indirect(slot); } diff --git a/tools/testing/radix-tree/test.c b/tools/testing/radix-tree/test.c index c9b0bd75b6c6..2bebf34cdc27 100644 --- a/tools/testing/radix-tree/test.c +++ b/tools/testing/radix-tree/test.c @@ -142,6 +142,8 @@ static int verify_node(struct radix_tree_node *slot, unsigned int tag, int i; int j; + slot = indirect_to_ptr(slot); + /* Verify consistency at this level */ for (i = 0; i < RADIX_TREE_TAG_LONGS; i++) { if (slot->tags[tag][i]) { @@ -184,8 +186,7 @@ void verify_tag_consistency(struct radix_tree_root *root, unsigned int tag) { if (!root->height) return; - verify_node(indirect_to_ptr(root->rnode), - tag, root->height, !!root_tag_get(root, tag)); + verify_node(root->rnode, tag, root->height, !!root_tag_get(root, tag)); } void item_kill_tree(struct radix_tree_root *root) -- 2.20.1