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authorIngo Molnar <mingo@elte.hu>2009-06-17 12:52:15 +0200
committerIngo Molnar <mingo@elte.hu>2009-06-17 12:56:49 +0200
commiteadb8a091b27a840de7450f84ecff5ef13476424 (patch)
tree58c3782d40def63baa8167f3d31e3048cb4c7660 /lib/radix-tree.c
parent73874005cd8800440be4299bd095387fff4b90ac (diff)
parent65795efbd380a832ae508b04dba8f8e53f0b84d9 (diff)
Merge branch 'linus' into tracing/hw-breakpoints
Conflicts: arch/x86/Kconfig arch/x86/kernel/traps.c arch/x86/power/cpu.c arch/x86/power/cpu_32.c kernel/Makefile Semantic conflict: arch/x86/kernel/hw_breakpoint.c Merge reason: Resolve the conflicts, move from put_cpu_no_sched() to put_cpu() in arch/x86/kernel/hw_breakpoint.c. Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'lib/radix-tree.c')
-rw-r--r--lib/radix-tree.c110
1 files changed, 63 insertions, 47 deletions
diff --git a/lib/radix-tree.c b/lib/radix-tree.c
index 4bb42a0344e..23abbd93cae 100644
--- a/lib/radix-tree.c
+++ b/lib/radix-tree.c
@@ -351,20 +351,12 @@ int radix_tree_insert(struct radix_tree_root *root,
}
EXPORT_SYMBOL(radix_tree_insert);
-/**
- * radix_tree_lookup_slot - lookup a slot in a radix tree
- * @root: radix tree root
- * @index: index key
- *
- * Returns: the slot corresponding to the position @index in the
- * radix tree @root. This is useful for update-if-exists operations.
- *
- * This function can be called under rcu_read_lock iff the slot is not
- * modified by radix_tree_replace_slot, otherwise it must be called
- * exclusive from other writers. Any dereference of the slot must be done
- * using radix_tree_deref_slot.
+/*
+ * is_slot == 1 : search for the slot.
+ * is_slot == 0 : search for the node.
*/
-void **radix_tree_lookup_slot(struct radix_tree_root *root, unsigned long index)
+static void *radix_tree_lookup_element(struct radix_tree_root *root,
+ unsigned long index, int is_slot)
{
unsigned int height, shift;
struct radix_tree_node *node, **slot;
@@ -376,7 +368,7 @@ void **radix_tree_lookup_slot(struct radix_tree_root *root, unsigned long index)
if (!radix_tree_is_indirect_ptr(node)) {
if (index > 0)
return NULL;
- return (void **)&root->rnode;
+ return is_slot ? (void *)&root->rnode : node;
}
node = radix_tree_indirect_to_ptr(node);
@@ -397,7 +389,25 @@ void **radix_tree_lookup_slot(struct radix_tree_root *root, unsigned long index)
height--;
} while (height > 0);
- return (void **)slot;
+ return is_slot ? (void *)slot:node;
+}
+
+/**
+ * radix_tree_lookup_slot - lookup a slot in a radix tree
+ * @root: radix tree root
+ * @index: index key
+ *
+ * Returns: the slot corresponding to the position @index in the
+ * radix tree @root. This is useful for update-if-exists operations.
+ *
+ * This function can be called under rcu_read_lock iff the slot is not
+ * modified by radix_tree_replace_slot, otherwise it must be called
+ * exclusive from other writers. Any dereference of the slot must be done
+ * using radix_tree_deref_slot.
+ */
+void **radix_tree_lookup_slot(struct radix_tree_root *root, unsigned long index)
+{
+ return (void **)radix_tree_lookup_element(root, index, 1);
}
EXPORT_SYMBOL(radix_tree_lookup_slot);
@@ -415,38 +425,7 @@ EXPORT_SYMBOL(radix_tree_lookup_slot);
*/
void *radix_tree_lookup(struct radix_tree_root *root, unsigned long index)
{
- unsigned int height, shift;
- struct radix_tree_node *node, **slot;
-
- node = rcu_dereference(root->rnode);
- if (node == NULL)
- return NULL;
-
- if (!radix_tree_is_indirect_ptr(node)) {
- if (index > 0)
- return NULL;
- return node;
- }
- node = radix_tree_indirect_to_ptr(node);
-
- height = node->height;
- if (index > radix_tree_maxindex(height))
- return NULL;
-
- shift = (height-1) * RADIX_TREE_MAP_SHIFT;
-
- do {
- slot = (struct radix_tree_node **)
- (node->slots + ((index>>shift) & RADIX_TREE_MAP_MASK));
- node = rcu_dereference(*slot);
- if (node == NULL)
- return NULL;
-
- shift -= RADIX_TREE_MAP_SHIFT;
- height--;
- } while (height > 0);
-
- return node;
+ return radix_tree_lookup_element(root, index, 0);
}
EXPORT_SYMBOL(radix_tree_lookup);
@@ -666,6 +645,43 @@ unsigned long radix_tree_next_hole(struct radix_tree_root *root,
}
EXPORT_SYMBOL(radix_tree_next_hole);
+/**
+ * radix_tree_prev_hole - find the prev hole (not-present entry)
+ * @root: tree root
+ * @index: index key
+ * @max_scan: maximum range to search
+ *
+ * Search backwards in the range [max(index-max_scan+1, 0), index]
+ * for the first hole.
+ *
+ * Returns: the index of the hole if found, otherwise returns an index
+ * outside of the set specified (in which case 'index - return >= max_scan'
+ * will be true). In rare cases of wrap-around, LONG_MAX will be returned.
+ *
+ * radix_tree_next_hole may be called under rcu_read_lock. However, like
+ * radix_tree_gang_lookup, this will not atomically search a snapshot of
+ * the tree at a single point in time. For example, if a hole is created
+ * at index 10, then subsequently a hole is created at index 5,
+ * radix_tree_prev_hole covering both indexes may return 5 if called under
+ * rcu_read_lock.
+ */
+unsigned long radix_tree_prev_hole(struct radix_tree_root *root,
+ unsigned long index, unsigned long max_scan)
+{
+ unsigned long i;
+
+ for (i = 0; i < max_scan; i++) {
+ if (!radix_tree_lookup(root, index))
+ break;
+ index--;
+ if (index == LONG_MAX)
+ break;
+ }
+
+ return index;
+}
+EXPORT_SYMBOL(radix_tree_prev_hole);
+
static unsigned int
__lookup(struct radix_tree_node *slot, void ***results, unsigned long index,
unsigned int max_items, unsigned long *next_index)