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linux-davinci-2.6.23
Commit daff89f3 authored by Jonathan Corbet's avatar Jonathan Corbet Committed by Linus Torvalds
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[PATCH] radix-tree documentation cleanups 

Documentation changes to help radix tree users avoid overrunning the tags
array.  RADIX_TREE_TAGS moves to linux/radix-tree.h and is now known as
RADIX_TREE_MAX_TAGS (Nick Piggin's idea).  Tag parameters are changed to
unsigned, and some comments are updated.
Signed-off-by: default avatarJonathan Corbet <corbet@lwn.net>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent 57070d01
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Showing with 35 additions and 27 deletions
include/linux/radix-tree.h
View file @ daff89f3
......@@ -45,6 +45,8 @@ do { \
(root)->rnode = NULL; \
} while (0)
#define RADIX_TREE_MAX_TAGS 2
int radix_tree_insert(struct radix_tree_root *, unsigned long, void *);
void *radix_tree_lookup(struct radix_tree_root *, unsigned long);
void **radix_tree_lookup_slot(struct radix_tree_root *, unsigned long);
......@@ -55,15 +57,16 @@ radix_tree_gang_lookup(struct radix_tree_root *root, void **results,
int radix_tree_preload(gfp_t gfp_mask);
void radix_tree_init(void);
void *radix_tree_tag_set(struct radix_tree_root *root,
unsigned long index, int tag);
unsigned long index, unsigned int tag);
void *radix_tree_tag_clear(struct radix_tree_root *root,
unsigned long index, int tag);
unsigned long index, unsigned int tag);
int radix_tree_tag_get(struct radix_tree_root *root,
unsigned long index, int tag);
unsigned long index, unsigned int tag);
unsigned int
radix_tree_gang_lookup_tag(struct radix_tree_root *root, void **results,
unsigned long first_index, unsigned int max_items, int tag);
int radix_tree_tagged(struct radix_tree_root *root, int tag);
unsigned long first_index, unsigned int max_items,
unsigned int tag);
int radix_tree_tagged(struct radix_tree_root *root, unsigned int tag);
static inline void radix_tree_preload_end(void)
{
......
lib/radix-tree.c
View file @ daff89f3
......@@ -37,7 +37,6 @@
#else
#define RADIX_TREE_MAP_SHIFT 3 /* For more stressful testing */
#endif
#define RADIX_TREE_TAGS 2
#define RADIX_TREE_MAP_SIZE (1UL << RADIX_TREE_MAP_SHIFT)
#define RADIX_TREE_MAP_MASK (RADIX_TREE_MAP_SIZE-1)
......@@ -48,7 +47,7 @@
struct radix_tree_node {
unsigned int count;
void *slots[RADIX_TREE_MAP_SIZE];
unsigned long tags[RADIX_TREE_TAGS][RADIX_TREE_TAG_LONGS];
unsigned long tags[RADIX_TREE_MAX_TAGS][RADIX_TREE_TAG_LONGS];
};
struct radix_tree_path {
......@@ -135,17 +134,20 @@ out:
return ret;
}
static inline void tag_set(struct radix_tree_node *node, int tag, int offset)
static inline void tag_set(struct radix_tree_node *node, unsigned int tag,
int offset)
{
__set_bit(offset, node->tags[tag]);
}
static inline void tag_clear(struct radix_tree_node *node, int tag, int offset)
static inline void tag_clear(struct radix_tree_node *node, unsigned int tag,
int offset)
{
__clear_bit(offset, node->tags[tag]);
}
static inline int tag_get(struct radix_tree_node *node, int tag, int offset)
static inline int tag_get(struct radix_tree_node *node, unsigned int tag,
int offset)
{
return test_bit(offset, node->tags[tag]);
}
......@@ -154,7 +156,7 @@ static inline int tag_get(struct radix_tree_node *node, int tag, int offset)
* Returns 1 if any slot in the node has this tag set.
* Otherwise returns 0.
*/
static inline int any_tag_set(struct radix_tree_node *node, int tag)
static inline int any_tag_set(struct radix_tree_node *node, unsigned int tag)
{
int idx;
for (idx = 0; idx < RADIX_TREE_TAG_LONGS; idx++) {
......@@ -180,7 +182,7 @@ static int radix_tree_extend(struct radix_tree_root *root, unsigned long index)
{
struct radix_tree_node *node;
unsigned int height;
char tags[RADIX_TREE_TAGS];
char tags[RADIX_TREE_MAX_TAGS];
int tag;
/* Figure out what the height should be. */
......@@ -197,7 +199,7 @@ static int radix_tree_extend(struct radix_tree_root *root, unsigned long index)
* Prepare the tag status of the top-level node for propagation
* into the newly-pushed top-level node(s)
*/
for (tag = 0; tag < RADIX_TREE_TAGS; tag++) {
for (tag = 0; tag < RADIX_TREE_MAX_TAGS; tag++) {
tags[tag] = 0;
if (any_tag_set(root->rnode, tag))
tags[tag] = 1;
......@@ -211,7 +213,7 @@ static int radix_tree_extend(struct radix_tree_root *root, unsigned long index)
node->slots[0] = root->rnode;
/* Propagate the aggregated tag info into the new root */
for (tag = 0; tag < RADIX_TREE_TAGS; tag++) {
for (tag = 0; tag < RADIX_TREE_MAX_TAGS; tag++) {
if (tags[tag])
tag_set(node, tag, 0);
}
......@@ -349,14 +351,15 @@ EXPORT_SYMBOL(radix_tree_lookup);
* @index: index key
* @tag: tag index
*
* Set the search tag corresponging to @index in the radix tree. From
* 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
* item is a bug.
*/
void *radix_tree_tag_set(struct radix_tree_root *root,
unsigned long index, int tag)
unsigned long index, unsigned int tag)
{
unsigned int height, shift;
struct radix_tree_node *slot;
......@@ -390,7 +393,8 @@ EXPORT_SYMBOL(radix_tree_tag_set);
* @index: index key
* @tag: tag index
*
* Clear the search tag corresponging to @index in the radix tree. If
* 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
* next-to-leaf node, etc.
*
......@@ -398,7 +402,7 @@ EXPORT_SYMBOL(radix_tree_tag_set);
* has the same return value and semantics as radix_tree_lookup().
*/
void *radix_tree_tag_clear(struct radix_tree_root *root,
unsigned long index, int tag)
unsigned long index, unsigned int tag)
{
struct radix_tree_path path[RADIX_TREE_MAX_PATH], *pathp = path;
struct radix_tree_node *slot;
......@@ -450,7 +454,7 @@ 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
* @tag: tag index (< RADIX_TREE_MAX_TAGS)
*
* Return values:
*
......@@ -459,7 +463,7 @@ EXPORT_SYMBOL(radix_tree_tag_clear);
* -1: tag present, unset
*/
int radix_tree_tag_get(struct radix_tree_root *root,
unsigned long index, int tag)
unsigned long index, unsigned int tag)
{
unsigned int height, shift;
struct radix_tree_node *slot;
......@@ -592,7 +596,7 @@ EXPORT_SYMBOL(radix_tree_gang_lookup);
*/
static unsigned int
__lookup_tag(struct radix_tree_root *root, void **results, unsigned long index,
unsigned int max_items, unsigned long *next_index, int tag)
unsigned int max_items, unsigned long *next_index, unsigned int tag)
{
unsigned int nr_found = 0;
unsigned int shift;
......@@ -646,7 +650,7 @@ out:
* @results: where the results of the lookup are placed
* @first_index: start the lookup from this key
* @max_items: place up to this many items at *results
* @tag: the tag index
* @tag: the tag index (< RADIX_TREE_MAX_TAGS)
*
* Performs an index-ascending scan of the tree for present items which
* have the tag indexed by @tag set. Places the items at *@results and
......@@ -654,7 +658,8 @@ out:
*/
unsigned int
radix_tree_gang_lookup_tag(struct radix_tree_root *root, void **results,
unsigned long first_index, unsigned int max_items, int tag)
unsigned long first_index, unsigned int max_items,
unsigned int tag)
{
const unsigned long max_index = radix_tree_maxindex(root->height);
unsigned long cur_index = first_index;
......@@ -716,7 +721,7 @@ void *radix_tree_delete(struct radix_tree_root *root, unsigned long index)
struct radix_tree_node *slot;
unsigned int height, shift;
void *ret = NULL;
char tags[RADIX_TREE_TAGS];
char tags[RADIX_TREE_MAX_TAGS];
int nr_cleared_tags;
int tag;
int offset;
......@@ -751,7 +756,7 @@ void *radix_tree_delete(struct radix_tree_root *root, unsigned long index)
* Clear all tags associated with the just-deleted item
*/
nr_cleared_tags = 0;
for (tag = 0; tag < RADIX_TREE_TAGS; tag++) {
for (tag = 0; tag < RADIX_TREE_MAX_TAGS; tag++) {
tags[tag] = 1;
if (tag_get(pathp->node, tag, pathp->offset)) {
tag_clear(pathp->node, tag, pathp->offset);
......@@ -763,7 +768,7 @@ void *radix_tree_delete(struct radix_tree_root *root, unsigned long index)
}
for (pathp--; nr_cleared_tags && pathp->node; pathp--) {
for (tag = 0; tag < RADIX_TREE_TAGS; tag++) {
for (tag = 0; tag < RADIX_TREE_MAX_TAGS; tag++) {
if (tags[tag])
continue;
......@@ -801,7 +806,7 @@ EXPORT_SYMBOL(radix_tree_delete);
* @root: radix tree root
* @tag: tag to test
*/
int radix_tree_tagged(struct radix_tree_root *root, int tag)
int radix_tree_tagged(struct radix_tree_root *root, unsigned int tag)
{
struct radix_tree_node *rnode;
rnode = root->rnode;
......
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