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 <willy@linux.intel.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Matthew Wilcox <willy@linux.intel.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/lib/radix-tree.c b/lib/radix-tree.c
index 224b369..ff91792 100644 (file)
--- 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 c9b0bd7..2bebf34 100644 (file)
--- 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)