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radix-tree: rewrite radix_tree_locate_item

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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>
This commit is contained in:
Matthew Wilcox
2016-05-20 17:02:46 -07:00
committed by Linus Torvalds
parent 8a14f4d832
commit 0a2efc6c80
2 changed files with 62 additions and 57 deletions
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89
lib/radix-tree.c
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@@ -1303,58 +1303,54 @@ EXPORT_SYMBOL(radix_tree_gang_lookup_tag_slot);
#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 @@ unsigned long radix_tree_locate_item(struct radix_tree_root *root, void *item)
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 @@ unsigned long radix_tree_locate_item(struct radix_tree_root *root, void *item)
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)