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Diffstat (limited to 'include/linux/radix-tree.h')
-rw-r--r--include/linux/radix-tree.h36
1 files changed, 33 insertions, 3 deletions
diff --git a/include/linux/radix-tree.h b/include/linux/radix-tree.h
index 23241c2fecce..b7edf8251455 100644
--- a/include/linux/radix-tree.h
+++ b/include/linux/radix-tree.h
@@ -39,7 +39,15 @@
* when it is shrunk, before we rcu free the node. See shrink code for
* details.
*/
-#define RADIX_TREE_INDIRECT_PTR 1
+#define RADIX_TREE_INDIRECT_PTR 1
+/*
+ * A common use of the radix tree is to store pointers to struct pages;
+ * but shmem/tmpfs needs also to store swap entries in the same tree:
+ * those are marked as exceptional entries to distinguish them.
+ * EXCEPTIONAL_ENTRY tests the bit, EXCEPTIONAL_SHIFT shifts content past it.
+ */
+#define RADIX_TREE_EXCEPTIONAL_ENTRY 2
+#define RADIX_TREE_EXCEPTIONAL_SHIFT 2
#define radix_tree_indirect_to_ptr(ptr) \
radix_tree_indirect_to_ptr((void __force *)(ptr))
@@ -174,6 +182,28 @@ static inline int radix_tree_deref_retry(void *arg)
}
/**
+ * radix_tree_exceptional_entry - radix_tree_deref_slot gave exceptional entry?
+ * @arg: value returned by radix_tree_deref_slot
+ * Returns: 0 if well-aligned pointer, non-0 if exceptional entry.
+ */
+static inline int radix_tree_exceptional_entry(void *arg)
+{
+ /* Not unlikely because radix_tree_exception often tested first */
+ return (unsigned long)arg & RADIX_TREE_EXCEPTIONAL_ENTRY;
+}
+
+/**
+ * radix_tree_exception - radix_tree_deref_slot returned either exception?
+ * @arg: value returned by radix_tree_deref_slot
+ * Returns: 0 if well-aligned pointer, non-0 if either kind of exception.
+ */
+static inline int radix_tree_exception(void *arg)
+{
+ return unlikely((unsigned long)arg &
+ (RADIX_TREE_INDIRECT_PTR | RADIX_TREE_EXCEPTIONAL_ENTRY));
+}
+
+/**
* radix_tree_replace_slot - replace item in a slot
* @pslot: pointer to slot, returned by radix_tree_lookup_slot
* @item: new item to store in the slot.
@@ -194,8 +224,8 @@ void *radix_tree_delete(struct radix_tree_root *, unsigned long);
unsigned int
radix_tree_gang_lookup(struct radix_tree_root *root, void **results,
unsigned long first_index, unsigned int max_items);
-unsigned int
-radix_tree_gang_lookup_slot(struct radix_tree_root *root, void ***results,
+unsigned int radix_tree_gang_lookup_slot(struct radix_tree_root *root,
+ void ***results, unsigned long *indices,
unsigned long first_index, unsigned int max_items);
unsigned long radix_tree_next_hole(struct radix_tree_root *root,
unsigned long index, unsigned long max_scan);