radix-tree: rewrite radix_tree_locate_item
Use the new multi-order support functions to rewrite
radix_tree_locate_item(). Modify the locate tests to test multiorder
entries too.
[hughd@google.com: radix_tree_locate_item() is often returning the wrong index]
Link: http://lkml.kernel.org/r/alpine.LSU.2.11.1605012108490.1166@eggly.anvils
Signed-off-by: Matthew Wilcox <willy@linux.intel.com>
Reviewed-by: Ross Zwisler <ross.zwisler@linux.intel.com>
Cc: Konstantin Khlebnikov <koct9i@gmail.com>
Cc: Kirill Shutemov <kirill.shutemov@linux.intel.com>
Cc: Jan Kara <jack@suse.com>
Cc: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/lib/radix-tree.c b/lib/radix-tree.c
index 9b5d8a9..8329a2e 100644
--- a/lib/radix-tree.c
+++ b/lib/radix-tree.c
@@ -1303,58 +1303,54 @@
#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;
+ shift = height * 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)
- 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;
- }
- goto out;
- }
- slot = indirect_to_ptr(slot);
+ do {
shift -= RADIX_TREE_MAP_SHIFT;
- }
- /* 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;
+ 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;
+ if (!radix_tree_is_indirect_ptr(node)) {
+ if (node == item) {
+ info->found_index = index;
+ info->stop = true;
+ goto out;
+ }
+ continue;
+ }
+ node = indirect_to_ptr(node);
+ if (is_sibling_entry(slot, node))
+ continue;
+ slot = node;
+ break;
}
- }
- index += RADIX_TREE_MAP_SIZE;
+ if (i == RADIX_TREE_MAP_SIZE)
+ break;
+ } while (shift);
+
out:
+ if ((index == 0) && (i == RADIX_TREE_MAP_SIZE))
+ info->stop = true;
return index;
}
@@ -1372,7 +1368,10 @@
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();
@@ -1380,24 +1379,24 @@
if (!radix_tree_is_indirect_ptr(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);
+
+ 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)