* Copyright (C) 2005 SGI, Christoph Lameter
* Copyright (C) 2006 Nick Piggin
* Copyright (C) 2012 Konstantin Khlebnikov
+ * Copyright (C) 2016 Intel, Matthew Wilcox
+ * Copyright (C) 2016 Intel, Ross Zwisler
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License as
#include <linux/preempt.h> /* in_interrupt() */
-/*
- * The height_to_maxindex array needs to be one deeper than the maximum
- * path as height 0 holds only 1 entry.
- */
-static unsigned long height_to_maxindex[RADIX_TREE_MAX_PATH + 1] __read_mostly;
-
/*
* Radix tree node cache.
*/
* Per-cpu pool of preloaded nodes
*/
struct radix_tree_preload {
- int nr;
+ unsigned nr;
/* nodes->private_data points to next preallocated node */
struct radix_tree_node *nodes;
};
static DEFINE_PER_CPU(struct radix_tree_preload, radix_tree_preloads) = { 0, };
-static inline void *ptr_to_indirect(void *ptr)
+static inline void *node_to_entry(void *ptr)
+{
+ return (void *)((unsigned long)ptr | RADIX_TREE_INTERNAL_NODE);
+}
+
+#define RADIX_TREE_RETRY node_to_entry(NULL)
+
+#ifdef CONFIG_RADIX_TREE_MULTIORDER
+/* Sibling slots point directly to another slot in the same node */
+static inline bool is_sibling_entry(struct radix_tree_node *parent, void *node)
+{
+ void **ptr = node;
+ return (parent->slots <= ptr) &&
+ (ptr < parent->slots + RADIX_TREE_MAP_SIZE);
+}
+#else
+static inline bool is_sibling_entry(struct radix_tree_node *parent, void *node)
{
- return (void *)((unsigned long)ptr | RADIX_TREE_INDIRECT_PTR);
+ return false;
}
+#endif
-static inline void *indirect_to_ptr(void *ptr)
+static inline unsigned long get_slot_offset(struct radix_tree_node *parent,
+ void **slot)
{
- return (void *)((unsigned long)ptr & ~RADIX_TREE_INDIRECT_PTR);
+ return slot - parent->slots;
+}
+
+static unsigned int radix_tree_descend(struct radix_tree_node *parent,
+ struct radix_tree_node **nodep, unsigned long index)
+{
+ unsigned int offset = (index >> parent->shift) & RADIX_TREE_MAP_MASK;
+ void **entry = rcu_dereference_raw(parent->slots[offset]);
+
+#ifdef CONFIG_RADIX_TREE_MULTIORDER
+ if (radix_tree_is_internal_node(entry)) {
+ unsigned long siboff = get_slot_offset(parent, entry);
+ if (siboff < RADIX_TREE_MAP_SIZE) {
+ offset = siboff;
+ entry = rcu_dereference_raw(parent->slots[offset]);
+ }
+ }
+#endif
+
+ *nodep = (void *)entry;
+ return offset;
}
static inline gfp_t root_gfp_mask(struct radix_tree_root *root)
root->gfp_mask |= (__force gfp_t)(1 << (tag + __GFP_BITS_SHIFT));
}
-static inline void root_tag_clear(struct radix_tree_root *root, unsigned int tag)
+static inline void root_tag_clear(struct radix_tree_root *root, unsigned tag)
{
root->gfp_mask &= (__force gfp_t)~(1 << (tag + __GFP_BITS_SHIFT));
}
static inline int root_tag_get(struct radix_tree_root *root, unsigned int tag)
{
- return (__force unsigned)root->gfp_mask & (1 << (tag + __GFP_BITS_SHIFT));
+ return (__force int)root->gfp_mask & (1 << (tag + __GFP_BITS_SHIFT));
+}
+
+static inline unsigned root_tags_get(struct radix_tree_root *root)
+{
+ return (__force unsigned)root->gfp_mask >> __GFP_BITS_SHIFT;
}
/*
*/
static inline int any_tag_set(struct radix_tree_node *node, unsigned int tag)
{
- int idx;
+ unsigned idx;
for (idx = 0; idx < RADIX_TREE_TAG_LONGS; idx++) {
if (node->tags[tag][idx])
return 1;
return size;
}
-#if 0
-static void dump_node(void *slot, int height, int offset)
+#ifndef __KERNEL__
+static void dump_node(struct radix_tree_node *node, unsigned long index)
{
- struct radix_tree_node *node;
- int i;
+ unsigned long i;
- if (!slot)
- return;
+ pr_debug("radix node: %p offset %d tags %lx %lx %lx shift %d count %d parent %p\n",
+ node, node->offset,
+ node->tags[0][0], node->tags[1][0], node->tags[2][0],
+ node->shift, node->count, node->parent);
- if (height == 0) {
- pr_debug("radix entry %p offset %d\n", slot, offset);
- return;
+ for (i = 0; i < RADIX_TREE_MAP_SIZE; i++) {
+ unsigned long first = index | (i << node->shift);
+ unsigned long last = first | ((1UL << node->shift) - 1);
+ void *entry = node->slots[i];
+ if (!entry)
+ continue;
+ if (is_sibling_entry(node, entry)) {
+ pr_debug("radix sblng %p offset %ld val %p indices %ld-%ld\n",
+ entry, i,
+ *(void **)entry_to_node(entry),
+ first, last);
+ } else if (!radix_tree_is_internal_node(entry)) {
+ pr_debug("radix entry %p offset %ld indices %ld-%ld\n",
+ entry, i, first, last);
+ } else {
+ dump_node(entry_to_node(entry), first);
+ }
}
-
- node = indirect_to_ptr(slot);
- pr_debug("radix node: %p offset %d tags %lx %lx %lx path %x count %d parent %p\n",
- slot, offset, node->tags[0][0], node->tags[1][0],
- node->tags[2][0], node->path, node->count, node->parent);
-
- for (i = 0; i < RADIX_TREE_MAP_SIZE; i++)
- dump_node(node->slots[i], height - 1, i);
}
/* For debug */
static void radix_tree_dump(struct radix_tree_root *root)
{
- pr_debug("radix root: %p height %d rnode %p tags %x\n",
- root, root->height, root->rnode,
+ pr_debug("radix root: %p rnode %p tags %x\n",
+ root, root->rnode,
root->gfp_mask >> __GFP_BITS_SHIFT);
- if (!radix_tree_is_indirect_ptr(root->rnode))
+ if (!radix_tree_is_internal_node(root->rnode))
return;
- dump_node(root->rnode, root->height, 0);
+ dump_node(entry_to_node(root->rnode), 0);
}
#endif
gfp_t gfp_mask = root_gfp_mask(root);
/*
- * Preload code isn't irq safe and it doesn't make sence to use
- * preloading in the interrupt anyway as all the allocations have to
- * be atomic. So just do normal allocation when in interrupt.
+ * Preload code isn't irq safe and it doesn't make sense to use
+ * preloading during an interrupt anyway as all the allocations have
+ * to be atomic. So just do normal allocation when in interrupt.
*/
if (!gfpflags_allow_blocking(gfp_mask) && !in_interrupt()) {
struct radix_tree_preload *rtp;
ret = kmem_cache_alloc(radix_tree_node_cachep,
gfp_mask | __GFP_ACCOUNT);
out:
- BUG_ON(radix_tree_is_indirect_ptr(ret));
+ BUG_ON(radix_tree_is_internal_node(ret));
return ret;
}
EXPORT_SYMBOL(radix_tree_maybe_preload);
/*
- * Return the maximum key which can be store into a
- * radix tree with height HEIGHT.
+ * The maximum index which can be stored in a radix tree
*/
-static inline unsigned long radix_tree_maxindex(unsigned int height)
+static inline unsigned long shift_maxindex(unsigned int shift)
+{
+ return (RADIX_TREE_MAP_SIZE << shift) - 1;
+}
+
+static inline unsigned long node_maxindex(struct radix_tree_node *node)
+{
+ return shift_maxindex(node->shift);
+}
+
+static unsigned radix_tree_load_root(struct radix_tree_root *root,
+ struct radix_tree_node **nodep, unsigned long *maxindex)
{
- return height_to_maxindex[height];
+ struct radix_tree_node *node = rcu_dereference_raw(root->rnode);
+
+ *nodep = node;
+
+ if (likely(radix_tree_is_internal_node(node))) {
+ node = entry_to_node(node);
+ *maxindex = node_maxindex(node);
+ return node->shift + RADIX_TREE_MAP_SHIFT;
+ }
+
+ *maxindex = 0;
+ return 0;
}
/*
* Extend a radix tree so it can store key @index.
*/
static int radix_tree_extend(struct radix_tree_root *root,
- unsigned long index, unsigned order)
+ unsigned long index, unsigned int shift)
{
- struct radix_tree_node *node;
struct radix_tree_node *slot;
- unsigned int height;
+ unsigned int maxshift;
int tag;
- /* Figure out what the height should be. */
- height = root->height + 1;
- while (index > radix_tree_maxindex(height))
- height++;
+ /* Figure out what the shift should be. */
+ maxshift = shift;
+ while (index > shift_maxindex(maxshift))
+ maxshift += RADIX_TREE_MAP_SHIFT;
- if ((root->rnode == NULL) && (order == 0)) {
- root->height = height;
+ slot = root->rnode;
+ if (!slot)
goto out;
- }
do {
- unsigned int newheight;
- if (!(node = radix_tree_node_alloc(root)))
+ struct radix_tree_node *node = radix_tree_node_alloc(root);
+
+ if (!node)
return -ENOMEM;
/* Propagate the aggregated tag info into the new root */
tag_set(node, tag, 0);
}
- /* Increase the height. */
- newheight = root->height+1;
- BUG_ON(newheight & ~RADIX_TREE_HEIGHT_MASK);
- node->path = newheight;
+ BUG_ON(shift > BITS_PER_LONG);
+ node->shift = shift;
+ node->offset = 0;
node->count = 1;
node->parent = NULL;
- slot = root->rnode;
- if (radix_tree_is_indirect_ptr(slot) && newheight > 1) {
- slot = indirect_to_ptr(slot);
- slot->parent = node;
- slot = ptr_to_indirect(slot);
- }
+ if (radix_tree_is_internal_node(slot))
+ entry_to_node(slot)->parent = node;
node->slots[0] = slot;
- node = ptr_to_indirect(node);
- rcu_assign_pointer(root->rnode, node);
- root->height = newheight;
- } while (height > root->height);
+ slot = node_to_entry(node);
+ rcu_assign_pointer(root->rnode, slot);
+ shift += RADIX_TREE_MAP_SHIFT;
+ } while (shift <= maxshift);
out:
- return 0;
+ return maxshift + RADIX_TREE_MAP_SHIFT;
}
/**
unsigned order, struct radix_tree_node **nodep,
void ***slotp)
{
- struct radix_tree_node *node = NULL, *slot;
- unsigned int height, shift, offset;
- int error;
+ struct radix_tree_node *node = NULL, *child;
+ void **slot = (void **)&root->rnode;
+ unsigned long maxindex;
+ unsigned int shift, offset = 0;
+ unsigned long max = index | ((1UL << order) - 1);
- BUG_ON((0 < order) && (order < RADIX_TREE_MAP_SHIFT));
+ shift = radix_tree_load_root(root, &child, &maxindex);
/* Make sure the tree is high enough. */
- if (index > radix_tree_maxindex(root->height)) {
- error = radix_tree_extend(root, index, order);
- if (error)
+ if (max > maxindex) {
+ int error = radix_tree_extend(root, max, shift);
+ if (error < 0)
return error;
+ shift = error;
+ child = root->rnode;
+ if (order == shift)
+ shift += RADIX_TREE_MAP_SHIFT;
}
- slot = root->rnode;
-
- height = root->height;
- shift = height * RADIX_TREE_MAP_SHIFT;
-
- offset = 0; /* uninitialised var warning */
while (shift > order) {
- if (slot == NULL) {
+ shift -= RADIX_TREE_MAP_SHIFT;
+ if (child == NULL) {
/* Have to add a child node. */
- if (!(slot = radix_tree_node_alloc(root)))
+ child = radix_tree_node_alloc(root);
+ if (!child)
return -ENOMEM;
- slot->path = height;
- slot->parent = node;
- if (node) {
- rcu_assign_pointer(node->slots[offset],
- ptr_to_indirect(slot));
+ child->shift = shift;
+ child->offset = offset;
+ child->parent = node;
+ rcu_assign_pointer(*slot, node_to_entry(child));
+ if (node)
node->count++;
- slot->path |= offset << RADIX_TREE_HEIGHT_SHIFT;
- } else
- rcu_assign_pointer(root->rnode,
- ptr_to_indirect(slot));
- } else if (!radix_tree_is_indirect_ptr(slot))
+ } else if (!radix_tree_is_internal_node(child))
break;
/* Go a level down */
- height--;
- shift -= RADIX_TREE_MAP_SHIFT;
- offset = (index >> shift) & RADIX_TREE_MAP_MASK;
- node = indirect_to_ptr(slot);
- slot = node->slots[offset];
+ node = entry_to_node(child);
+ offset = radix_tree_descend(node, &child, index);
+ slot = &node->slots[offset];
}
+#ifdef CONFIG_RADIX_TREE_MULTIORDER
/* Insert pointers to the canonical entry */
- if ((shift - order) > 0) {
- int i, n = 1 << (shift - order);
+ if (order > shift) {
+ unsigned i, n = 1 << (order - shift);
offset = offset & ~(n - 1);
- slot = ptr_to_indirect(&node->slots[offset]);
+ slot = &node->slots[offset];
+ child = node_to_entry(slot);
for (i = 0; i < n; i++) {
- if (node->slots[offset + i])
+ if (slot[i])
return -EEXIST;
}
for (i = 1; i < n; i++) {
- rcu_assign_pointer(node->slots[offset + i], slot);
+ rcu_assign_pointer(slot[i], child);
node->count++;
}
}
+#endif
if (nodep)
*nodep = node;
if (slotp)
- *slotp = node ? node->slots + offset : (void **)&root->rnode;
+ *slotp = slot;
return 0;
}
void **slot;
int error;
- BUG_ON(radix_tree_is_indirect_ptr(item));
+ BUG_ON(radix_tree_is_internal_node(item));
error = __radix_tree_create(root, index, order, &node, &slot);
if (error)
rcu_assign_pointer(*slot, item);
if (node) {
+ unsigned offset = get_slot_offset(node, slot);
node->count++;
- BUG_ON(tag_get(node, 0, index & RADIX_TREE_MAP_MASK));
- BUG_ON(tag_get(node, 1, index & RADIX_TREE_MAP_MASK));
+ BUG_ON(tag_get(node, 0, offset));
+ BUG_ON(tag_get(node, 1, offset));
+ BUG_ON(tag_get(node, 2, offset));
} else {
- BUG_ON(root_tag_get(root, 0));
- BUG_ON(root_tag_get(root, 1));
+ BUG_ON(root_tags_get(root));
}
return 0;
struct radix_tree_node **nodep, void ***slotp)
{
struct radix_tree_node *node, *parent;
- unsigned int height, shift;
+ unsigned long maxindex;
void **slot;
- node = rcu_dereference_raw(root->rnode);
- if (node == NULL)
+ restart:
+ parent = NULL;
+ slot = (void **)&root->rnode;
+ radix_tree_load_root(root, &node, &maxindex);
+ if (index > maxindex)
return NULL;
- if (!radix_tree_is_indirect_ptr(node)) {
- if (index > 0)
- return NULL;
+ while (radix_tree_is_internal_node(node)) {
+ unsigned offset;
- if (nodep)
- *nodep = NULL;
- if (slotp)
- *slotp = (void **)&root->rnode;
- return node;
+ if (node == RADIX_TREE_RETRY)
+ goto restart;
+ parent = entry_to_node(node);
+ offset = radix_tree_descend(parent, &node, index);
+ slot = parent->slots + offset;
}
- node = indirect_to_ptr(node);
-
- height = node->path & RADIX_TREE_HEIGHT_MASK;
- if (index > radix_tree_maxindex(height))
- return NULL;
-
- shift = (height-1) * RADIX_TREE_MAP_SHIFT;
-
- do {
- parent = node;
- slot = node->slots + ((index >> shift) & RADIX_TREE_MAP_MASK);
- node = rcu_dereference_raw(*slot);
- if (node == NULL)
- return NULL;
- if (!radix_tree_is_indirect_ptr(node))
- break;
- node = indirect_to_ptr(node);
-
- shift -= RADIX_TREE_MAP_SHIFT;
- height--;
- } while (height > 0);
if (nodep)
*nodep = parent;
* radix_tree_tag_set - set a tag on a radix tree node
* @root: radix tree root
* @index: index key
- * @tag: tag index
+ * @tag: tag index
*
* Set the search tag (which must be < RADIX_TREE_MAX_TAGS)
* corresponding to @index in the radix tree. From
* the root all the way down to the leaf node.
*
- * Returns the address of the tagged item. Setting a tag on a not-present
+ * Returns the address of the tagged item. Setting a tag on a not-present
* item is a bug.
*/
void *radix_tree_tag_set(struct radix_tree_root *root,
unsigned long index, unsigned int tag)
{
- unsigned int height, shift;
- struct radix_tree_node *slot;
+ struct radix_tree_node *node, *parent;
+ unsigned long maxindex;
- height = root->height;
- BUG_ON(index > radix_tree_maxindex(height));
+ radix_tree_load_root(root, &node, &maxindex);
+ BUG_ON(index > maxindex);
- slot = indirect_to_ptr(root->rnode);
- shift = (height - 1) * RADIX_TREE_MAP_SHIFT;
+ while (radix_tree_is_internal_node(node)) {
+ unsigned offset;
- while (height > 0) {
- int offset;
+ parent = entry_to_node(node);
+ offset = radix_tree_descend(parent, &node, index);
+ BUG_ON(!node);
- offset = (index >> shift) & RADIX_TREE_MAP_MASK;
- if (!tag_get(slot, tag, offset))
- tag_set(slot, tag, offset);
- slot = slot->slots[offset];
- BUG_ON(slot == NULL);
- if (!radix_tree_is_indirect_ptr(slot))
- break;
- slot = indirect_to_ptr(slot);
- shift -= RADIX_TREE_MAP_SHIFT;
- height--;
+ if (!tag_get(parent, tag, offset))
+ tag_set(parent, tag, offset);
}
/* set the root's tag bit */
- if (slot && !root_tag_get(root, tag))
+ if (!root_tag_get(root, tag))
root_tag_set(root, tag);
- return slot;
+ return node;
}
EXPORT_SYMBOL(radix_tree_tag_set);
+static void node_tag_clear(struct radix_tree_root *root,
+ struct radix_tree_node *node,
+ unsigned int tag, unsigned int offset)
+{
+ while (node) {
+ if (!tag_get(node, tag, offset))
+ return;
+ tag_clear(node, tag, offset);
+ if (any_tag_set(node, tag))
+ return;
+
+ offset = node->offset;
+ node = node->parent;
+ }
+
+ /* clear the root's tag bit */
+ if (root_tag_get(root, tag))
+ root_tag_clear(root, tag);
+}
+
/**
* radix_tree_tag_clear - clear a tag on a radix tree node
* @root: radix tree root
* @index: index key
- * @tag: tag index
+ * @tag: tag index
*
* Clear the search tag (which must be < RADIX_TREE_MAX_TAGS)
- * corresponding to @index in the radix tree. If
- * this causes the leaf node to have no tags set then clear the tag in the
+ * corresponding to @index in the radix tree. If this causes
+ * the leaf node to have no tags set then clear the tag in the
* next-to-leaf node, etc.
*
* Returns the address of the tagged item on success, else NULL. ie:
void *radix_tree_tag_clear(struct radix_tree_root *root,
unsigned long index, unsigned int tag)
{
- struct radix_tree_node *node = NULL;
- struct radix_tree_node *slot = NULL;
- unsigned int height, shift;
+ struct radix_tree_node *node, *parent;
+ unsigned long maxindex;
int uninitialized_var(offset);
- height = root->height;
- if (index > radix_tree_maxindex(height))
- goto out;
-
- shift = height * RADIX_TREE_MAP_SHIFT;
- slot = root->rnode;
-
- while (shift) {
- if (slot == NULL)
- goto out;
- if (!radix_tree_is_indirect_ptr(slot))
- break;
- slot = indirect_to_ptr(slot);
-
- shift -= RADIX_TREE_MAP_SHIFT;
- offset = (index >> shift) & RADIX_TREE_MAP_MASK;
- node = slot;
- slot = slot->slots[offset];
- }
-
- if (slot == NULL)
- goto out;
+ radix_tree_load_root(root, &node, &maxindex);
+ if (index > maxindex)
+ return NULL;
- while (node) {
- if (!tag_get(node, tag, offset))
- goto out;
- tag_clear(node, tag, offset);
- if (any_tag_set(node, tag))
- goto out;
+ parent = NULL;
- index >>= RADIX_TREE_MAP_SHIFT;
- offset = index & RADIX_TREE_MAP_MASK;
- node = node->parent;
+ while (radix_tree_is_internal_node(node)) {
+ parent = entry_to_node(node);
+ offset = radix_tree_descend(parent, &node, index);
}
- /* clear the root's tag bit */
- if (root_tag_get(root, tag))
- root_tag_clear(root, tag);
+ if (node)
+ node_tag_clear(root, parent, tag, offset);
-out:
- return slot;
+ return node;
}
EXPORT_SYMBOL(radix_tree_tag_clear);
* radix_tree_tag_get - get a tag on a radix tree node
* @root: radix tree root
* @index: index key
- * @tag: tag index (< RADIX_TREE_MAX_TAGS)
+ * @tag: tag index (< RADIX_TREE_MAX_TAGS)
*
* Return values:
*
int radix_tree_tag_get(struct radix_tree_root *root,
unsigned long index, unsigned int tag)
{
- unsigned int height, shift;
- struct radix_tree_node *node;
+ struct radix_tree_node *node, *parent;
+ unsigned long maxindex;
- /* check the root's tag bit */
if (!root_tag_get(root, tag))
return 0;
- node = rcu_dereference_raw(root->rnode);
- if (node == NULL)
+ radix_tree_load_root(root, &node, &maxindex);
+ if (index > maxindex)
return 0;
-
- if (!radix_tree_is_indirect_ptr(node))
- return (index == 0);
- node = indirect_to_ptr(node);
-
- height = node->path & RADIX_TREE_HEIGHT_MASK;
- if (index > radix_tree_maxindex(height))
+ if (node == NULL)
return 0;
- shift = (height - 1) * RADIX_TREE_MAP_SHIFT;
+ while (radix_tree_is_internal_node(node)) {
+ unsigned offset;
- for ( ; ; ) {
- int offset;
+ parent = entry_to_node(node);
+ offset = radix_tree_descend(parent, &node, index);
- if (node == NULL)
+ if (!node)
return 0;
- node = indirect_to_ptr(node);
-
- offset = (index >> shift) & RADIX_TREE_MAP_MASK;
- if (!tag_get(node, tag, offset))
+ if (!tag_get(parent, tag, offset))
return 0;
- if (height == 1)
- return 1;
- node = rcu_dereference_raw(node->slots[offset]);
- if (!radix_tree_is_indirect_ptr(node))
- return 1;
- shift -= RADIX_TREE_MAP_SHIFT;
- height--;
+ if (node == RADIX_TREE_RETRY)
+ break;
}
+
+ return 1;
}
EXPORT_SYMBOL(radix_tree_tag_get);
+static inline void __set_iter_shift(struct radix_tree_iter *iter,
+ unsigned int shift)
+{
+#ifdef CONFIG_RADIX_TREE_MULTIORDER
+ iter->shift = shift;
+#endif
+}
+
/**
* radix_tree_next_chunk - find next chunk of slots for iteration
*
void **radix_tree_next_chunk(struct radix_tree_root *root,
struct radix_tree_iter *iter, unsigned flags)
{
- unsigned shift, tag = flags & RADIX_TREE_ITER_TAG_MASK;
- struct radix_tree_node *rnode, *node;
- unsigned long index, offset, height;
+ unsigned tag = flags & RADIX_TREE_ITER_TAG_MASK;
+ struct radix_tree_node *node, *child;
+ unsigned long index, offset, maxindex;
if ((flags & RADIX_TREE_ITER_TAGGED) && !root_tag_get(root, tag))
return NULL;
if (!index && iter->index)
return NULL;
- rnode = rcu_dereference_raw(root->rnode);
- if (radix_tree_is_indirect_ptr(rnode)) {
- rnode = indirect_to_ptr(rnode);
- } else if (rnode && !index) {
+ restart:
+ radix_tree_load_root(root, &child, &maxindex);
+ if (index > maxindex)
+ return NULL;
+ if (!child)
+ return NULL;
+
+ if (!radix_tree_is_internal_node(child)) {
/* Single-slot tree */
- iter->index = 0;
- iter->next_index = 1;
+ iter->index = index;
+ iter->next_index = maxindex + 1;
iter->tags = 1;
+ __set_iter_shift(iter, 0);
return (void **)&root->rnode;
- } else
- return NULL;
-
-restart:
- height = rnode->path & RADIX_TREE_HEIGHT_MASK;
- shift = (height - 1) * RADIX_TREE_MAP_SHIFT;
- offset = index >> shift;
+ }
- /* Index outside of the tree */
- if (offset >= RADIX_TREE_MAP_SIZE)
- return NULL;
+ do {
+ node = entry_to_node(child);
+ offset = radix_tree_descend(node, &child, index);
- node = rnode;
- while (1) {
- struct radix_tree_node *slot;
if ((flags & RADIX_TREE_ITER_TAGGED) ?
- !test_bit(offset, node->tags[tag]) :
- !node->slots[offset]) {
+ !tag_get(node, tag, offset) : !child) {
/* Hole detected */
if (flags & RADIX_TREE_ITER_CONTIG)
return NULL;
offset + 1);
else
while (++offset < RADIX_TREE_MAP_SIZE) {
- if (node->slots[offset])
+ void *slot = node->slots[offset];
+ if (is_sibling_entry(node, slot))
+ continue;
+ if (slot)
break;
}
- index &= ~((RADIX_TREE_MAP_SIZE << shift) - 1);
- index += offset << shift;
+ index &= ~node_maxindex(node);
+ index += offset << node->shift;
/* Overflow after ~0UL */
if (!index)
return NULL;
if (offset == RADIX_TREE_MAP_SIZE)
goto restart;
+ child = rcu_dereference_raw(node->slots[offset]);
}
- /* This is leaf-node */
- if (!shift)
- break;
-
- slot = rcu_dereference_raw(node->slots[offset]);
- if (slot == NULL)
+ if ((child == NULL) || (child == RADIX_TREE_RETRY))
goto restart;
- if (!radix_tree_is_indirect_ptr(slot))
- break;
- node = indirect_to_ptr(slot);
- shift -= RADIX_TREE_MAP_SHIFT;
- offset = (index >> shift) & RADIX_TREE_MAP_MASK;
- }
+ } while (radix_tree_is_internal_node(child));
/* Update the iterator state */
- iter->index = index;
- iter->next_index = (index | RADIX_TREE_MAP_MASK) + 1;
+ iter->index = (index &~ node_maxindex(node)) | (offset << node->shift);
+ iter->next_index = (index | node_maxindex(node)) + 1;
+ __set_iter_shift(iter, node->shift);
/* Construct iter->tags bit-mask from node->tags[tag] array */
if (flags & RADIX_TREE_ITER_TAGGED) {
* set is outside the range we are scanning. This reults in dangling tags and
* can lead to problems with later tag operations (e.g. livelocks on lookups).
*
- * The function returns number of leaves where the tag was set and sets
+ * The function returns the number of leaves where the tag was set and sets
* *first_indexp to the first unscanned index.
* WARNING! *first_indexp can wrap if last_index is ULONG_MAX. Caller must
* be prepared to handle that.
unsigned long nr_to_tag,
unsigned int iftag, unsigned int settag)
{
- unsigned int height = root->height;
- struct radix_tree_node *node = NULL;
- struct radix_tree_node *slot;
- unsigned int shift;
+ struct radix_tree_node *parent, *node, *child;
+ unsigned long maxindex;
unsigned long tagged = 0;
unsigned long index = *first_indexp;
- last_index = min(last_index, radix_tree_maxindex(height));
+ radix_tree_load_root(root, &child, &maxindex);
+ last_index = min(last_index, maxindex);
if (index > last_index)
return 0;
if (!nr_to_tag)
*first_indexp = last_index + 1;
return 0;
}
- if (height == 0) {
+ if (!radix_tree_is_internal_node(child)) {
*first_indexp = last_index + 1;
root_tag_set(root, settag);
return 1;
}
- shift = (height - 1) * RADIX_TREE_MAP_SHIFT;
- slot = indirect_to_ptr(root->rnode);
+ node = entry_to_node(child);
for (;;) {
- unsigned long upindex;
- int offset;
-
- offset = (index >> shift) & RADIX_TREE_MAP_MASK;
- if (!slot->slots[offset])
+ unsigned offset = radix_tree_descend(node, &child, index);
+ if (!child)
goto next;
- if (!tag_get(slot, iftag, offset))
+ if (!tag_get(node, iftag, offset))
goto next;
- if (shift) {
- node = slot;
- slot = slot->slots[offset];
- if (radix_tree_is_indirect_ptr(slot)) {
- slot = indirect_to_ptr(slot);
- shift -= RADIX_TREE_MAP_SHIFT;
- continue;
- } else {
- slot = node;
- node = node->parent;
- }
+ /* Sibling slots never have tags set on them */
+ if (radix_tree_is_internal_node(child)) {
+ node = entry_to_node(child);
+ continue;
}
/* tag the leaf */
- tagged += 1 << shift;
- tag_set(slot, settag, offset);
+ tagged++;
+ tag_set(node, settag, offset);
/* walk back up the path tagging interior nodes */
- upindex = index;
- while (node) {
- upindex >>= RADIX_TREE_MAP_SHIFT;
- offset = upindex & RADIX_TREE_MAP_MASK;
-
+ parent = node;
+ for (;;) {
+ offset = parent->offset;
+ parent = parent->parent;
+ if (!parent)
+ break;
/* stop if we find a node with the tag already set */
- if (tag_get(node, settag, offset))
+ if (tag_get(parent, settag, offset))
break;
- tag_set(node, settag, offset);
- node = node->parent;
+ tag_set(parent, settag, offset);
}
-
- /*
- * Small optimization: now clear that node pointer.
- * Since all of this slot's ancestors now have the tag set
- * from setting it above, we have no further need to walk
- * back up the tree setting tags, until we update slot to
- * point to another radix_tree_node.
- */
- node = NULL;
-
-next:
- /* Go to next item at level determined by 'shift' */
- index = ((index >> shift) + 1) << shift;
+ next:
+ /* Go to next entry in node */
+ index = ((index >> node->shift) + 1) << node->shift;
/* Overflow can happen when last_index is ~0UL... */
if (index > last_index || !index)
break;
- if (tagged >= nr_to_tag)
- break;
- while (((index >> shift) & RADIX_TREE_MAP_MASK) == 0) {
+ offset = (index >> node->shift) & RADIX_TREE_MAP_MASK;
+ while (offset == 0) {
/*
* We've fully scanned this node. Go up. Because
* last_index is guaranteed to be in the tree, what
* we do below cannot wander astray.
*/
- slot = slot->parent;
- shift += RADIX_TREE_MAP_SHIFT;
+ node = node->parent;
+ offset = (index >> node->shift) & RADIX_TREE_MAP_MASK;
}
+ if (is_sibling_entry(node, node->slots[offset]))
+ goto next;
+ if (tagged >= nr_to_tag)
+ break;
}
/*
* We need not to tag the root tag if there is no tag which is set with
*
* Like radix_tree_lookup, radix_tree_gang_lookup may be called under
* rcu_read_lock. In this case, rather than the returned results being
- * an atomic snapshot of the tree at a single point in time, the semantics
- * of an RCU protected gang lookup are as though multiple radix_tree_lookups
- * have been issued in individual locks, and results stored in 'results'.
+ * an atomic snapshot of the tree at a single point in time, the
+ * semantics of an RCU protected gang lookup are as though multiple
+ * radix_tree_lookups have been issued in individual locks, and results
+ * stored in 'results'.
*/
unsigned int
radix_tree_gang_lookup(struct radix_tree_root *root, void **results,
results[ret] = rcu_dereference_raw(*slot);
if (!results[ret])
continue;
- if (radix_tree_is_indirect_ptr(results[ret])) {
+ if (radix_tree_is_internal_node(results[ret])) {
slot = radix_tree_iter_retry(&iter);
continue;
}
results[ret] = rcu_dereference_raw(*slot);
if (!results[ret])
continue;
- if (radix_tree_is_indirect_ptr(results[ret])) {
+ if (radix_tree_is_internal_node(results[ret])) {
slot = radix_tree_iter_retry(&iter);
continue;
}
#if defined(CONFIG_SHMEM) && defined(CONFIG_SWAP)
#include <linux/sched.h> /* 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;
-
- 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)
+ do {
+ unsigned int shift = slot->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;
- }
-
- 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;
+ if (!radix_tree_is_internal_node(node)) {
+ if (node == item) {
+ info->found_index = index;
+ info->stop = true;
+ goto out;
+ }
+ continue;
}
- goto out;
+ node = entry_to_node(node);
+ if (is_sibling_entry(slot, node))
+ continue;
+ slot = node;
+ break;
}
- slot = indirect_to_ptr(slot);
- shift -= RADIX_TREE_MAP_SHIFT;
- }
+ } while (i < RADIX_TREE_MAP_SIZE);
- /* 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;
}
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();
node = rcu_dereference_raw(root->rnode);
- if (!radix_tree_is_indirect_ptr(node)) {
+ if (!radix_tree_is_internal_node(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);
+ node = entry_to_node(node);
+
+ 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)
#endif /* CONFIG_SHMEM && CONFIG_SWAP */
/**
- * radix_tree_shrink - shrink height of a radix tree to minimal
+ * radix_tree_shrink - shrink radix tree to minimum height
* @root radix tree root
*/
-static inline void radix_tree_shrink(struct radix_tree_root *root)
+static inline bool radix_tree_shrink(struct radix_tree_root *root)
{
- /* try to shrink tree height */
- while (root->height > 0) {
- struct radix_tree_node *to_free = root->rnode;
- struct radix_tree_node *slot;
+ bool shrunk = false;
+
+ for (;;) {
+ struct radix_tree_node *node = root->rnode;
+ struct radix_tree_node *child;
- BUG_ON(!radix_tree_is_indirect_ptr(to_free));
- to_free = indirect_to_ptr(to_free);
+ if (!radix_tree_is_internal_node(node))
+ break;
+ node = entry_to_node(node);
/*
* The candidate node has more than one child, or its child
- * is not at the leftmost slot, or it is a multiorder entry,
- * we cannot shrink.
+ * is not at the leftmost slot, or the child is a multiorder
+ * entry, we cannot shrink.
*/
- if (to_free->count != 1)
+ if (node->count != 1)
break;
- slot = to_free->slots[0];
- if (!slot)
+ child = node->slots[0];
+ if (!child)
break;
+ if (!radix_tree_is_internal_node(child) && node->shift)
+ break;
+
+ if (radix_tree_is_internal_node(child))
+ entry_to_node(child)->parent = NULL;
/*
* We don't need rcu_assign_pointer(), since we are simply
* moving the node from one part of the tree to another: if it
* was safe to dereference the old pointer to it
- * (to_free->slots[0]), it will be safe to dereference the new
+ * (node->slots[0]), it will be safe to dereference the new
* one (root->rnode) as far as dependent read barriers go.
*/
- if (root->height > 1) {
- if (!radix_tree_is_indirect_ptr(slot))
- break;
-
- slot = indirect_to_ptr(slot);
- slot->parent = NULL;
- slot = ptr_to_indirect(slot);
- }
- root->rnode = slot;
- root->height--;
+ root->rnode = child;
/*
* We have a dilemma here. The node's slot[0] must not be
* their slot to become empty sooner or later.
*
* For example, lockless pagecache will look up a slot, deref
- * the page pointer, and if the page is 0 refcount it means it
+ * the page pointer, and if the page has 0 refcount it means it
* was concurrently deleted from pagecache so try the deref
* again. Fortunately there is already a requirement for logic
* to retry the entire slot lookup -- the indirect pointer
* also results in a stale slot). So tag the slot as indirect
* to force callers to retry.
*/
- if (root->height == 0)
- *((unsigned long *)&to_free->slots[0]) |=
- RADIX_TREE_INDIRECT_PTR;
+ if (!radix_tree_is_internal_node(child))
+ node->slots[0] = RADIX_TREE_RETRY;
- radix_tree_node_free(to_free);
+ radix_tree_node_free(node);
+ shrunk = true;
}
+
+ return shrunk;
}
/**
struct radix_tree_node *parent;
if (node->count) {
- if (node == indirect_to_ptr(root->rnode)) {
- radix_tree_shrink(root);
- if (root->height == 0)
- deleted = true;
- }
+ if (node == entry_to_node(root->rnode))
+ deleted |= radix_tree_shrink(root);
return deleted;
}
parent = node->parent;
if (parent) {
- unsigned int offset;
-
- offset = node->path >> RADIX_TREE_HEIGHT_SHIFT;
- parent->slots[offset] = NULL;
+ parent->slots[node->offset] = NULL;
parent->count--;
} else {
root_tag_clear_all(root);
- root->height = 0;
root->rnode = NULL;
}
return deleted;
}
+static inline void delete_sibling_entries(struct radix_tree_node *node,
+ void *ptr, unsigned offset)
+{
+#ifdef CONFIG_RADIX_TREE_MULTIORDER
+ int i;
+ for (i = 1; offset + i < RADIX_TREE_MAP_SIZE; i++) {
+ if (node->slots[offset + i] != ptr)
+ break;
+ node->slots[offset + i] = NULL;
+ node->count--;
+ }
+#endif
+}
+
/**
* radix_tree_delete_item - delete an item from a radix tree
* @root: radix tree root
unsigned long index, void *item)
{
struct radix_tree_node *node;
- unsigned int offset, i;
+ unsigned int offset;
void **slot;
void *entry;
int tag;
return entry;
}
- offset = index & RADIX_TREE_MAP_MASK;
+ offset = get_slot_offset(node, slot);
- /*
- * Clear all tags associated with the item to be deleted.
- * This way of doing it would be inefficient, but seldom is any set.
- */
- for (tag = 0; tag < RADIX_TREE_MAX_TAGS; tag++) {
- if (tag_get(node, tag, offset))
- radix_tree_tag_clear(root, index, tag);
- }
+ /* Clear all tags associated with the item to be deleted. */
+ for (tag = 0; tag < RADIX_TREE_MAX_TAGS; tag++)
+ node_tag_clear(root, node, tag, offset);
- /* Delete any sibling slots pointing to this slot */
- for (i = 1; offset + i < RADIX_TREE_MAP_SIZE; i++) {
- if (node->slots[offset + i] != ptr_to_indirect(slot))
- break;
- node->slots[offset + i] = NULL;
- node->count--;
- }
+ delete_sibling_entries(node, node_to_entry(slot), offset);
node->slots[offset] = NULL;
node->count--;
}
EXPORT_SYMBOL(radix_tree_delete);
+struct radix_tree_node *radix_tree_replace_clear_tags(
+ struct radix_tree_root *root,
+ unsigned long index, void *entry)
+{
+ struct radix_tree_node *node;
+ void **slot;
+
+ __radix_tree_lookup(root, index, &node, &slot);
+
+ if (node) {
+ unsigned int tag, offset = get_slot_offset(node, slot);
+ for (tag = 0; tag < RADIX_TREE_MAX_TAGS; tag++)
+ node_tag_clear(root, node, tag, offset);
+ } else {
+ /* Clear root node tags */
+ root->gfp_mask &= __GFP_BITS_MASK;
+ }
+
+ radix_tree_replace_slot(slot, entry);
+ return node;
+}
+
/**
* radix_tree_tagged - test whether any items in the tree are tagged
* @root: radix tree root
INIT_LIST_HEAD(&node->private_list);
}
-static __init unsigned long __maxindex(unsigned int height)
-{
- unsigned int width = height * RADIX_TREE_MAP_SHIFT;
- int shift = RADIX_TREE_INDEX_BITS - width;
-
- if (shift < 0)
- return ~0UL;
- if (shift >= BITS_PER_LONG)
- return 0UL;
- return ~0UL >> shift;
-}
-
-static __init void radix_tree_init_maxindex(void)
-{
- unsigned int i;
-
- for (i = 0; i < ARRAY_SIZE(height_to_maxindex); i++)
- height_to_maxindex[i] = __maxindex(i);
-}
-
static int radix_tree_callback(struct notifier_block *nfb,
- unsigned long action,
- void *hcpu)
+ unsigned long action, void *hcpu)
{
- int cpu = (long)hcpu;
- struct radix_tree_preload *rtp;
- struct radix_tree_node *node;
-
- /* Free per-cpu pool of perloaded nodes */
- if (action == CPU_DEAD || action == CPU_DEAD_FROZEN) {
- rtp = &per_cpu(radix_tree_preloads, cpu);
- while (rtp->nr) {
+ int cpu = (long)hcpu;
+ struct radix_tree_preload *rtp;
+ struct radix_tree_node *node;
+
+ /* Free per-cpu pool of preloaded nodes */
+ if (action == CPU_DEAD || action == CPU_DEAD_FROZEN) {
+ rtp = &per_cpu(radix_tree_preloads, cpu);
+ while (rtp->nr) {
node = rtp->nodes;
rtp->nodes = node->private_data;
kmem_cache_free(radix_tree_node_cachep, node);
rtp->nr--;
- }
- }
- return NOTIFY_OK;
+ }
+ }
+ return NOTIFY_OK;
}
void __init radix_tree_init(void)
sizeof(struct radix_tree_node), 0,
SLAB_PANIC | SLAB_RECLAIM_ACCOUNT,
radix_tree_node_ctor);
- radix_tree_init_maxindex();
hotcpu_notifier(radix_tree_callback, 0);
}
projects / linux-2.6-block.git / blobdiff