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authorMatthew Wilcox <willy@linux.intel.com>2016-03-17 14:21:48 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2016-03-17 15:09:34 -0700
commit339e6353046dd4f675304d696a88aefdd727298e (patch)
treebfe0c26987489add8c51ab13dbd65d348445e4b9 /lib
parent1366c37ed84b166a0fffe201154b0d3b78a3976b (diff)
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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>
Diffstat (limited to 'lib')
-rw-r--r--lib/radix-tree.c24
1 files changed, 18 insertions, 6 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);
}