2 * Copyright (C) 2001 Momchil Velikov
3 * Portions Copyright (C) 2001 Christoph Hellwig
4 * Copyright (C) 2005 SGI, Christoph Lameter
5 * Copyright (C) 2006 Nick Piggin
6 * Copyright (C) 2012 Konstantin Khlebnikov
7 * Copyright (C) 2016 Intel, Matthew Wilcox
8 * Copyright (C) 2016 Intel, Ross Zwisler
10 * This program is free software; you can redistribute it and/or
11 * modify it under the terms of the GNU General Public License as
12 * published by the Free Software Foundation; either version 2, or (at
13 * your option) any later version.
15 * This program is distributed in the hope that it will be useful, but
16 * WITHOUT ANY WARRANTY; without even the implied warranty of
17 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
18 * General Public License for more details.
20 * You should have received a copy of the GNU General Public License
21 * along with this program; if not, write to the Free Software
22 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
25 #include <linux/errno.h>
26 #include <linux/init.h>
27 #include <linux/kernel.h>
28 #include <linux/export.h>
29 #include <linux/radix-tree.h>
30 #include <linux/percpu.h>
31 #include <linux/slab.h>
32 #include <linux/kmemleak.h>
33 #include <linux/notifier.h>
34 #include <linux/cpu.h>
35 #include <linux/string.h>
36 #include <linux/bitops.h>
37 #include <linux/rcupdate.h>
38 #include <linux/preempt.h> /* in_interrupt() */
41 /* Number of nodes in fully populated tree of given height */
42 static unsigned long height_to_maxnodes
[RADIX_TREE_MAX_PATH
+ 1] __read_mostly
;
45 * Radix tree node cache.
47 static struct kmem_cache
*radix_tree_node_cachep
;
50 * The radix tree is variable-height, so an insert operation not only has
51 * to build the branch to its corresponding item, it also has to build the
52 * branch to existing items if the size has to be increased (by
55 * The worst case is a zero height tree with just a single item at index 0,
56 * and then inserting an item at index ULONG_MAX. This requires 2 new branches
57 * of RADIX_TREE_MAX_PATH size to be created, with only the root node shared.
60 #define RADIX_TREE_PRELOAD_SIZE (RADIX_TREE_MAX_PATH * 2 - 1)
63 * Per-cpu pool of preloaded nodes
65 struct radix_tree_preload
{
67 /* nodes->private_data points to next preallocated node */
68 struct radix_tree_node
*nodes
;
70 static DEFINE_PER_CPU(struct radix_tree_preload
, radix_tree_preloads
) = { 0, };
72 static inline void *node_to_entry(void *ptr
)
74 return (void *)((unsigned long)ptr
| RADIX_TREE_INTERNAL_NODE
);
77 #define RADIX_TREE_RETRY node_to_entry(NULL)
79 #ifdef CONFIG_RADIX_TREE_MULTIORDER
80 /* Sibling slots point directly to another slot in the same node */
81 static inline bool is_sibling_entry(struct radix_tree_node
*parent
, void *node
)
84 return (parent
->slots
<= ptr
) &&
85 (ptr
< parent
->slots
+ RADIX_TREE_MAP_SIZE
);
88 static inline bool is_sibling_entry(struct radix_tree_node
*parent
, void *node
)
94 static inline unsigned long get_slot_offset(struct radix_tree_node
*parent
,
97 return slot
- parent
->slots
;
100 static unsigned int radix_tree_descend(struct radix_tree_node
*parent
,
101 struct radix_tree_node
**nodep
, unsigned long index
)
103 unsigned int offset
= (index
>> parent
->shift
) & RADIX_TREE_MAP_MASK
;
104 void **entry
= rcu_dereference_raw(parent
->slots
[offset
]);
106 #ifdef CONFIG_RADIX_TREE_MULTIORDER
107 if (radix_tree_is_internal_node(entry
)) {
108 if (is_sibling_entry(parent
, entry
)) {
109 void **sibentry
= (void **) entry_to_node(entry
);
110 offset
= get_slot_offset(parent
, sibentry
);
111 entry
= rcu_dereference_raw(*sibentry
);
116 *nodep
= (void *)entry
;
120 static inline gfp_t
root_gfp_mask(struct radix_tree_root
*root
)
122 return root
->gfp_mask
& __GFP_BITS_MASK
;
125 static inline void tag_set(struct radix_tree_node
*node
, unsigned int tag
,
128 __set_bit(offset
, node
->tags
[tag
]);
131 static inline void tag_clear(struct radix_tree_node
*node
, unsigned int tag
,
134 __clear_bit(offset
, node
->tags
[tag
]);
137 static inline int tag_get(struct radix_tree_node
*node
, unsigned int tag
,
140 return test_bit(offset
, node
->tags
[tag
]);
143 static inline void root_tag_set(struct radix_tree_root
*root
, unsigned int tag
)
145 root
->gfp_mask
|= (__force gfp_t
)(1 << (tag
+ __GFP_BITS_SHIFT
));
148 static inline void root_tag_clear(struct radix_tree_root
*root
, unsigned tag
)
150 root
->gfp_mask
&= (__force gfp_t
)~(1 << (tag
+ __GFP_BITS_SHIFT
));
153 static inline void root_tag_clear_all(struct radix_tree_root
*root
)
155 root
->gfp_mask
&= __GFP_BITS_MASK
;
158 static inline int root_tag_get(struct radix_tree_root
*root
, unsigned int tag
)
160 return (__force
int)root
->gfp_mask
& (1 << (tag
+ __GFP_BITS_SHIFT
));
163 static inline unsigned root_tags_get(struct radix_tree_root
*root
)
165 return (__force
unsigned)root
->gfp_mask
>> __GFP_BITS_SHIFT
;
169 * Returns 1 if any slot in the node has this tag set.
170 * Otherwise returns 0.
172 static inline int any_tag_set(struct radix_tree_node
*node
, unsigned int tag
)
175 for (idx
= 0; idx
< RADIX_TREE_TAG_LONGS
; idx
++) {
176 if (node
->tags
[tag
][idx
])
183 * radix_tree_find_next_bit - find the next set bit in a memory region
185 * @addr: The address to base the search on
186 * @size: The bitmap size in bits
187 * @offset: The bitnumber to start searching at
189 * Unrollable variant of find_next_bit() for constant size arrays.
190 * Tail bits starting from size to roundup(size, BITS_PER_LONG) must be zero.
191 * Returns next bit offset, or size if nothing found.
193 static __always_inline
unsigned long
194 radix_tree_find_next_bit(const unsigned long *addr
,
195 unsigned long size
, unsigned long offset
)
197 if (!__builtin_constant_p(size
))
198 return find_next_bit(addr
, size
, offset
);
203 addr
+= offset
/ BITS_PER_LONG
;
204 tmp
= *addr
>> (offset
% BITS_PER_LONG
);
206 return __ffs(tmp
) + offset
;
207 offset
= (offset
+ BITS_PER_LONG
) & ~(BITS_PER_LONG
- 1);
208 while (offset
< size
) {
211 return __ffs(tmp
) + offset
;
212 offset
+= BITS_PER_LONG
;
219 static void dump_node(struct radix_tree_node
*node
, unsigned long index
)
223 pr_debug("radix node: %p offset %d tags %lx %lx %lx shift %d count %d exceptional %d parent %p\n",
225 node
->tags
[0][0], node
->tags
[1][0], node
->tags
[2][0],
226 node
->shift
, node
->count
, node
->exceptional
, node
->parent
);
228 for (i
= 0; i
< RADIX_TREE_MAP_SIZE
; i
++) {
229 unsigned long first
= index
| (i
<< node
->shift
);
230 unsigned long last
= first
| ((1UL << node
->shift
) - 1);
231 void *entry
= node
->slots
[i
];
234 if (is_sibling_entry(node
, entry
)) {
235 pr_debug("radix sblng %p offset %ld val %p indices %ld-%ld\n",
237 *(void **)entry_to_node(entry
),
239 } else if (!radix_tree_is_internal_node(entry
)) {
240 pr_debug("radix entry %p offset %ld indices %ld-%ld\n",
241 entry
, i
, first
, last
);
243 dump_node(entry_to_node(entry
), first
);
249 static void radix_tree_dump(struct radix_tree_root
*root
)
251 pr_debug("radix root: %p rnode %p tags %x\n",
253 root
->gfp_mask
>> __GFP_BITS_SHIFT
);
254 if (!radix_tree_is_internal_node(root
->rnode
))
256 dump_node(entry_to_node(root
->rnode
), 0);
261 * This assumes that the caller has performed appropriate preallocation, and
262 * that the caller has pinned this thread of control to the current CPU.
264 static struct radix_tree_node
*
265 radix_tree_node_alloc(struct radix_tree_root
*root
)
267 struct radix_tree_node
*ret
= NULL
;
268 gfp_t gfp_mask
= root_gfp_mask(root
);
271 * Preload code isn't irq safe and it doesn't make sense to use
272 * preloading during an interrupt anyway as all the allocations have
273 * to be atomic. So just do normal allocation when in interrupt.
275 if (!gfpflags_allow_blocking(gfp_mask
) && !in_interrupt()) {
276 struct radix_tree_preload
*rtp
;
279 * Even if the caller has preloaded, try to allocate from the
280 * cache first for the new node to get accounted to the memory
283 ret
= kmem_cache_alloc(radix_tree_node_cachep
,
284 gfp_mask
| __GFP_NOWARN
);
289 * Provided the caller has preloaded here, we will always
290 * succeed in getting a node here (and never reach
293 rtp
= this_cpu_ptr(&radix_tree_preloads
);
296 rtp
->nodes
= ret
->private_data
;
297 ret
->private_data
= NULL
;
301 * Update the allocation stack trace as this is more useful
304 kmemleak_update_trace(ret
);
307 ret
= kmem_cache_alloc(radix_tree_node_cachep
, gfp_mask
);
309 BUG_ON(radix_tree_is_internal_node(ret
));
313 static void radix_tree_node_rcu_free(struct rcu_head
*head
)
315 struct radix_tree_node
*node
=
316 container_of(head
, struct radix_tree_node
, rcu_head
);
320 * must only free zeroed nodes into the slab. radix_tree_shrink
321 * can leave us with a non-NULL entry in the first slot, so clear
322 * that here to make sure.
324 for (i
= 0; i
< RADIX_TREE_MAX_TAGS
; i
++)
325 tag_clear(node
, i
, 0);
327 node
->slots
[0] = NULL
;
329 kmem_cache_free(radix_tree_node_cachep
, node
);
333 radix_tree_node_free(struct radix_tree_node
*node
)
335 call_rcu(&node
->rcu_head
, radix_tree_node_rcu_free
);
339 * Load up this CPU's radix_tree_node buffer with sufficient objects to
340 * ensure that the addition of a single element in the tree cannot fail. On
341 * success, return zero, with preemption disabled. On error, return -ENOMEM
342 * with preemption not disabled.
344 * To make use of this facility, the radix tree must be initialised without
345 * __GFP_DIRECT_RECLAIM being passed to INIT_RADIX_TREE().
347 static int __radix_tree_preload(gfp_t gfp_mask
, int nr
)
349 struct radix_tree_preload
*rtp
;
350 struct radix_tree_node
*node
;
354 * Nodes preloaded by one cgroup can be be used by another cgroup, so
355 * they should never be accounted to any particular memory cgroup.
357 gfp_mask
&= ~__GFP_ACCOUNT
;
360 rtp
= this_cpu_ptr(&radix_tree_preloads
);
361 while (rtp
->nr
< nr
) {
363 node
= kmem_cache_alloc(radix_tree_node_cachep
, gfp_mask
);
367 rtp
= this_cpu_ptr(&radix_tree_preloads
);
369 node
->private_data
= rtp
->nodes
;
373 kmem_cache_free(radix_tree_node_cachep
, node
);
382 * Load up this CPU's radix_tree_node buffer with sufficient objects to
383 * ensure that the addition of a single element in the tree cannot fail. On
384 * success, return zero, with preemption disabled. On error, return -ENOMEM
385 * with preemption not disabled.
387 * To make use of this facility, the radix tree must be initialised without
388 * __GFP_DIRECT_RECLAIM being passed to INIT_RADIX_TREE().
390 int radix_tree_preload(gfp_t gfp_mask
)
392 /* Warn on non-sensical use... */
393 WARN_ON_ONCE(!gfpflags_allow_blocking(gfp_mask
));
394 return __radix_tree_preload(gfp_mask
, RADIX_TREE_PRELOAD_SIZE
);
396 EXPORT_SYMBOL(radix_tree_preload
);
399 * The same as above function, except we don't guarantee preloading happens.
400 * We do it, if we decide it helps. On success, return zero with preemption
401 * disabled. On error, return -ENOMEM with preemption not disabled.
403 int radix_tree_maybe_preload(gfp_t gfp_mask
)
405 if (gfpflags_allow_blocking(gfp_mask
))
406 return __radix_tree_preload(gfp_mask
, RADIX_TREE_PRELOAD_SIZE
);
407 /* Preloading doesn't help anything with this gfp mask, skip it */
411 EXPORT_SYMBOL(radix_tree_maybe_preload
);
414 * The same as function above, but preload number of nodes required to insert
415 * (1 << order) continuous naturally-aligned elements.
417 int radix_tree_maybe_preload_order(gfp_t gfp_mask
, int order
)
419 unsigned long nr_subtrees
;
420 int nr_nodes
, subtree_height
;
422 /* Preloading doesn't help anything with this gfp mask, skip it */
423 if (!gfpflags_allow_blocking(gfp_mask
)) {
429 * Calculate number and height of fully populated subtrees it takes to
430 * store (1 << order) elements.
432 nr_subtrees
= 1 << order
;
433 for (subtree_height
= 0; nr_subtrees
> RADIX_TREE_MAP_SIZE
;
435 nr_subtrees
>>= RADIX_TREE_MAP_SHIFT
;
438 * The worst case is zero height tree with a single item at index 0 and
439 * then inserting items starting at ULONG_MAX - (1 << order).
441 * This requires RADIX_TREE_MAX_PATH nodes to build branch from root to
444 nr_nodes
= RADIX_TREE_MAX_PATH
;
446 /* Plus branch to fully populated subtrees. */
447 nr_nodes
+= RADIX_TREE_MAX_PATH
- subtree_height
;
449 /* Root node is shared. */
452 /* Plus nodes required to build subtrees. */
453 nr_nodes
+= nr_subtrees
* height_to_maxnodes
[subtree_height
];
455 return __radix_tree_preload(gfp_mask
, nr_nodes
);
459 * The maximum index which can be stored in a radix tree
461 static inline unsigned long shift_maxindex(unsigned int shift
)
463 return (RADIX_TREE_MAP_SIZE
<< shift
) - 1;
466 static inline unsigned long node_maxindex(struct radix_tree_node
*node
)
468 return shift_maxindex(node
->shift
);
471 static unsigned radix_tree_load_root(struct radix_tree_root
*root
,
472 struct radix_tree_node
**nodep
, unsigned long *maxindex
)
474 struct radix_tree_node
*node
= rcu_dereference_raw(root
->rnode
);
478 if (likely(radix_tree_is_internal_node(node
))) {
479 node
= entry_to_node(node
);
480 *maxindex
= node_maxindex(node
);
481 return node
->shift
+ RADIX_TREE_MAP_SHIFT
;
489 * Extend a radix tree so it can store key @index.
491 static int radix_tree_extend(struct radix_tree_root
*root
,
492 unsigned long index
, unsigned int shift
)
494 struct radix_tree_node
*slot
;
495 unsigned int maxshift
;
498 /* Figure out what the shift should be. */
500 while (index
> shift_maxindex(maxshift
))
501 maxshift
+= RADIX_TREE_MAP_SHIFT
;
508 struct radix_tree_node
*node
= radix_tree_node_alloc(root
);
513 /* Propagate the aggregated tag info into the new root */
514 for (tag
= 0; tag
< RADIX_TREE_MAX_TAGS
; tag
++) {
515 if (root_tag_get(root
, tag
))
516 tag_set(node
, tag
, 0);
519 BUG_ON(shift
> BITS_PER_LONG
);
524 if (radix_tree_is_internal_node(slot
)) {
525 entry_to_node(slot
)->parent
= node
;
527 /* Moving an exceptional root->rnode to a node */
528 if (radix_tree_exceptional_entry(slot
))
529 node
->exceptional
= 1;
531 node
->slots
[0] = slot
;
532 slot
= node_to_entry(node
);
533 rcu_assign_pointer(root
->rnode
, slot
);
534 shift
+= RADIX_TREE_MAP_SHIFT
;
535 } while (shift
<= maxshift
);
537 return maxshift
+ RADIX_TREE_MAP_SHIFT
;
541 * radix_tree_shrink - shrink radix tree to minimum height
542 * @root radix tree root
544 static inline void radix_tree_shrink(struct radix_tree_root
*root
,
545 radix_tree_update_node_t update_node
,
549 struct radix_tree_node
*node
= root
->rnode
;
550 struct radix_tree_node
*child
;
552 if (!radix_tree_is_internal_node(node
))
554 node
= entry_to_node(node
);
557 * The candidate node has more than one child, or its child
558 * is not at the leftmost slot, or the child is a multiorder
559 * entry, we cannot shrink.
561 if (node
->count
!= 1)
563 child
= node
->slots
[0];
566 if (!radix_tree_is_internal_node(child
) && node
->shift
)
569 if (radix_tree_is_internal_node(child
))
570 entry_to_node(child
)->parent
= NULL
;
573 * We don't need rcu_assign_pointer(), since we are simply
574 * moving the node from one part of the tree to another: if it
575 * was safe to dereference the old pointer to it
576 * (node->slots[0]), it will be safe to dereference the new
577 * one (root->rnode) as far as dependent read barriers go.
582 * We have a dilemma here. The node's slot[0] must not be
583 * NULLed in case there are concurrent lookups expecting to
584 * find the item. However if this was a bottom-level node,
585 * then it may be subject to the slot pointer being visible
586 * to callers dereferencing it. If item corresponding to
587 * slot[0] is subsequently deleted, these callers would expect
588 * their slot to become empty sooner or later.
590 * For example, lockless pagecache will look up a slot, deref
591 * the page pointer, and if the page has 0 refcount it means it
592 * was concurrently deleted from pagecache so try the deref
593 * again. Fortunately there is already a requirement for logic
594 * to retry the entire slot lookup -- the indirect pointer
595 * problem (replacing direct root node with an indirect pointer
596 * also results in a stale slot). So tag the slot as indirect
597 * to force callers to retry.
600 if (!radix_tree_is_internal_node(child
)) {
601 node
->slots
[0] = RADIX_TREE_RETRY
;
603 update_node(node
, private);
606 radix_tree_node_free(node
);
610 static void delete_node(struct radix_tree_root
*root
,
611 struct radix_tree_node
*node
,
612 radix_tree_update_node_t update_node
, void *private)
615 struct radix_tree_node
*parent
;
618 if (node
== entry_to_node(root
->rnode
))
619 radix_tree_shrink(root
, update_node
, private);
623 parent
= node
->parent
;
625 parent
->slots
[node
->offset
] = NULL
;
628 root_tag_clear_all(root
);
632 radix_tree_node_free(node
);
639 * __radix_tree_create - create a slot in a radix tree
640 * @root: radix tree root
642 * @order: index occupies 2^order aligned slots
643 * @nodep: returns node
644 * @slotp: returns slot
646 * Create, if necessary, and return the node and slot for an item
647 * at position @index in the radix tree @root.
649 * Until there is more than one item in the tree, no nodes are
650 * allocated and @root->rnode is used as a direct slot instead of
651 * pointing to a node, in which case *@nodep will be NULL.
653 * Returns -ENOMEM, or 0 for success.
655 int __radix_tree_create(struct radix_tree_root
*root
, unsigned long index
,
656 unsigned order
, struct radix_tree_node
**nodep
,
659 struct radix_tree_node
*node
= NULL
, *child
;
660 void **slot
= (void **)&root
->rnode
;
661 unsigned long maxindex
;
662 unsigned int shift
, offset
= 0;
663 unsigned long max
= index
| ((1UL << order
) - 1);
665 shift
= radix_tree_load_root(root
, &child
, &maxindex
);
667 /* Make sure the tree is high enough. */
668 if (max
> maxindex
) {
669 int error
= radix_tree_extend(root
, max
, shift
);
675 shift
+= RADIX_TREE_MAP_SHIFT
;
678 while (shift
> order
) {
679 shift
-= RADIX_TREE_MAP_SHIFT
;
681 /* Have to add a child node. */
682 child
= radix_tree_node_alloc(root
);
685 child
->shift
= shift
;
686 child
->offset
= offset
;
687 child
->parent
= node
;
688 rcu_assign_pointer(*slot
, node_to_entry(child
));
691 } else if (!radix_tree_is_internal_node(child
))
694 /* Go a level down */
695 node
= entry_to_node(child
);
696 offset
= radix_tree_descend(node
, &child
, index
);
697 slot
= &node
->slots
[offset
];
700 #ifdef CONFIG_RADIX_TREE_MULTIORDER
701 /* Insert pointers to the canonical entry */
703 unsigned i
, n
= 1 << (order
- shift
);
704 offset
= offset
& ~(n
- 1);
705 slot
= &node
->slots
[offset
];
706 child
= node_to_entry(slot
);
707 for (i
= 0; i
< n
; i
++) {
712 for (i
= 1; i
< n
; i
++) {
713 rcu_assign_pointer(slot
[i
], child
);
727 * __radix_tree_insert - insert into a radix tree
728 * @root: radix tree root
730 * @order: key covers the 2^order indices around index
731 * @item: item to insert
733 * Insert an item into the radix tree at position @index.
735 int __radix_tree_insert(struct radix_tree_root
*root
, unsigned long index
,
736 unsigned order
, void *item
)
738 struct radix_tree_node
*node
;
742 BUG_ON(radix_tree_is_internal_node(item
));
744 error
= __radix_tree_create(root
, index
, order
, &node
, &slot
);
749 rcu_assign_pointer(*slot
, item
);
752 unsigned offset
= get_slot_offset(node
, slot
);
754 if (radix_tree_exceptional_entry(item
))
756 BUG_ON(tag_get(node
, 0, offset
));
757 BUG_ON(tag_get(node
, 1, offset
));
758 BUG_ON(tag_get(node
, 2, offset
));
760 BUG_ON(root_tags_get(root
));
765 EXPORT_SYMBOL(__radix_tree_insert
);
768 * __radix_tree_lookup - lookup an item in a radix tree
769 * @root: radix tree root
771 * @nodep: returns node
772 * @slotp: returns slot
774 * Lookup and return the item at position @index in the radix
777 * Until there is more than one item in the tree, no nodes are
778 * allocated and @root->rnode is used as a direct slot instead of
779 * pointing to a node, in which case *@nodep will be NULL.
781 void *__radix_tree_lookup(struct radix_tree_root
*root
, unsigned long index
,
782 struct radix_tree_node
**nodep
, void ***slotp
)
784 struct radix_tree_node
*node
, *parent
;
785 unsigned long maxindex
;
790 slot
= (void **)&root
->rnode
;
791 radix_tree_load_root(root
, &node
, &maxindex
);
792 if (index
> maxindex
)
795 while (radix_tree_is_internal_node(node
)) {
798 if (node
== RADIX_TREE_RETRY
)
800 parent
= entry_to_node(node
);
801 offset
= radix_tree_descend(parent
, &node
, index
);
802 slot
= parent
->slots
+ offset
;
813 * radix_tree_lookup_slot - lookup a slot in a radix tree
814 * @root: radix tree root
817 * Returns: the slot corresponding to the position @index in the
818 * radix tree @root. This is useful for update-if-exists operations.
820 * This function can be called under rcu_read_lock iff the slot is not
821 * modified by radix_tree_replace_slot, otherwise it must be called
822 * exclusive from other writers. Any dereference of the slot must be done
823 * using radix_tree_deref_slot.
825 void **radix_tree_lookup_slot(struct radix_tree_root
*root
, unsigned long index
)
829 if (!__radix_tree_lookup(root
, index
, NULL
, &slot
))
833 EXPORT_SYMBOL(radix_tree_lookup_slot
);
836 * radix_tree_lookup - perform lookup operation on a radix tree
837 * @root: radix tree root
840 * Lookup the item at the position @index in the radix tree @root.
842 * This function can be called under rcu_read_lock, however the caller
843 * must manage lifetimes of leaf nodes (eg. RCU may also be used to free
844 * them safely). No RCU barriers are required to access or modify the
845 * returned item, however.
847 void *radix_tree_lookup(struct radix_tree_root
*root
, unsigned long index
)
849 return __radix_tree_lookup(root
, index
, NULL
, NULL
);
851 EXPORT_SYMBOL(radix_tree_lookup
);
853 static void replace_slot(struct radix_tree_root
*root
,
854 struct radix_tree_node
*node
,
855 void **slot
, void *item
,
856 bool warn_typeswitch
)
858 void *old
= rcu_dereference_raw(*slot
);
859 int count
, exceptional
;
861 WARN_ON_ONCE(radix_tree_is_internal_node(item
));
863 count
= !!item
- !!old
;
864 exceptional
= !!radix_tree_exceptional_entry(item
) -
865 !!radix_tree_exceptional_entry(old
);
867 WARN_ON_ONCE(warn_typeswitch
&& (count
|| exceptional
));
870 node
->count
+= count
;
871 node
->exceptional
+= exceptional
;
874 rcu_assign_pointer(*slot
, item
);
878 * __radix_tree_replace - replace item in a slot
879 * @root: radix tree root
880 * @node: pointer to tree node
881 * @slot: pointer to slot in @node
882 * @item: new item to store in the slot.
883 * @update_node: callback for changing leaf nodes
884 * @private: private data to pass to @update_node
886 * For use with __radix_tree_lookup(). Caller must hold tree write locked
887 * across slot lookup and replacement.
889 void __radix_tree_replace(struct radix_tree_root
*root
,
890 struct radix_tree_node
*node
,
891 void **slot
, void *item
,
892 radix_tree_update_node_t update_node
, void *private)
895 * This function supports replacing exceptional entries and
896 * deleting entries, but that needs accounting against the
897 * node unless the slot is root->rnode.
899 replace_slot(root
, node
, slot
, item
,
900 !node
&& slot
!= (void **)&root
->rnode
);
906 update_node(node
, private);
908 delete_node(root
, node
, update_node
, private);
912 * radix_tree_replace_slot - replace item in a slot
913 * @root: radix tree root
914 * @slot: pointer to slot
915 * @item: new item to store in the slot.
917 * For use with radix_tree_lookup_slot(), radix_tree_gang_lookup_slot(),
918 * radix_tree_gang_lookup_tag_slot(). Caller must hold tree write locked
919 * across slot lookup and replacement.
921 * NOTE: This cannot be used to switch between non-entries (empty slots),
922 * regular entries, and exceptional entries, as that requires accounting
923 * inside the radix tree node. When switching from one type of entry or
924 * deleting, use __radix_tree_lookup() and __radix_tree_replace().
926 void radix_tree_replace_slot(struct radix_tree_root
*root
,
927 void **slot
, void *item
)
929 replace_slot(root
, NULL
, slot
, item
, true);
933 * radix_tree_tag_set - set a tag on a radix tree node
934 * @root: radix tree root
938 * Set the search tag (which must be < RADIX_TREE_MAX_TAGS)
939 * corresponding to @index in the radix tree. From
940 * the root all the way down to the leaf node.
942 * Returns the address of the tagged item. Setting a tag on a not-present
945 void *radix_tree_tag_set(struct radix_tree_root
*root
,
946 unsigned long index
, unsigned int tag
)
948 struct radix_tree_node
*node
, *parent
;
949 unsigned long maxindex
;
951 radix_tree_load_root(root
, &node
, &maxindex
);
952 BUG_ON(index
> maxindex
);
954 while (radix_tree_is_internal_node(node
)) {
957 parent
= entry_to_node(node
);
958 offset
= radix_tree_descend(parent
, &node
, index
);
961 if (!tag_get(parent
, tag
, offset
))
962 tag_set(parent
, tag
, offset
);
965 /* set the root's tag bit */
966 if (!root_tag_get(root
, tag
))
967 root_tag_set(root
, tag
);
971 EXPORT_SYMBOL(radix_tree_tag_set
);
973 static void node_tag_clear(struct radix_tree_root
*root
,
974 struct radix_tree_node
*node
,
975 unsigned int tag
, unsigned int offset
)
978 if (!tag_get(node
, tag
, offset
))
980 tag_clear(node
, tag
, offset
);
981 if (any_tag_set(node
, tag
))
984 offset
= node
->offset
;
988 /* clear the root's tag bit */
989 if (root_tag_get(root
, tag
))
990 root_tag_clear(root
, tag
);
994 * radix_tree_tag_clear - clear a tag on a radix tree node
995 * @root: radix tree root
999 * Clear the search tag (which must be < RADIX_TREE_MAX_TAGS)
1000 * corresponding to @index in the radix tree. If this causes
1001 * the leaf node to have no tags set then clear the tag in the
1002 * next-to-leaf node, etc.
1004 * Returns the address of the tagged item on success, else NULL. ie:
1005 * has the same return value and semantics as radix_tree_lookup().
1007 void *radix_tree_tag_clear(struct radix_tree_root
*root
,
1008 unsigned long index
, unsigned int tag
)
1010 struct radix_tree_node
*node
, *parent
;
1011 unsigned long maxindex
;
1012 int uninitialized_var(offset
);
1014 radix_tree_load_root(root
, &node
, &maxindex
);
1015 if (index
> maxindex
)
1020 while (radix_tree_is_internal_node(node
)) {
1021 parent
= entry_to_node(node
);
1022 offset
= radix_tree_descend(parent
, &node
, index
);
1026 node_tag_clear(root
, parent
, tag
, offset
);
1030 EXPORT_SYMBOL(radix_tree_tag_clear
);
1033 * radix_tree_tag_get - get a tag on a radix tree node
1034 * @root: radix tree root
1036 * @tag: tag index (< RADIX_TREE_MAX_TAGS)
1040 * 0: tag not present or not set
1043 * Note that the return value of this function may not be relied on, even if
1044 * the RCU lock is held, unless tag modification and node deletion are excluded
1047 int radix_tree_tag_get(struct radix_tree_root
*root
,
1048 unsigned long index
, unsigned int tag
)
1050 struct radix_tree_node
*node
, *parent
;
1051 unsigned long maxindex
;
1053 if (!root_tag_get(root
, tag
))
1056 radix_tree_load_root(root
, &node
, &maxindex
);
1057 if (index
> maxindex
)
1062 while (radix_tree_is_internal_node(node
)) {
1065 parent
= entry_to_node(node
);
1066 offset
= radix_tree_descend(parent
, &node
, index
);
1070 if (!tag_get(parent
, tag
, offset
))
1072 if (node
== RADIX_TREE_RETRY
)
1078 EXPORT_SYMBOL(radix_tree_tag_get
);
1080 static inline void __set_iter_shift(struct radix_tree_iter
*iter
,
1083 #ifdef CONFIG_RADIX_TREE_MULTIORDER
1084 iter
->shift
= shift
;
1089 * radix_tree_next_chunk - find next chunk of slots for iteration
1091 * @root: radix tree root
1092 * @iter: iterator state
1093 * @flags: RADIX_TREE_ITER_* flags and tag index
1094 * Returns: pointer to chunk first slot, or NULL if iteration is over
1096 void **radix_tree_next_chunk(struct radix_tree_root
*root
,
1097 struct radix_tree_iter
*iter
, unsigned flags
)
1099 unsigned tag
= flags
& RADIX_TREE_ITER_TAG_MASK
;
1100 struct radix_tree_node
*node
, *child
;
1101 unsigned long index
, offset
, maxindex
;
1103 if ((flags
& RADIX_TREE_ITER_TAGGED
) && !root_tag_get(root
, tag
))
1107 * Catch next_index overflow after ~0UL. iter->index never overflows
1108 * during iterating; it can be zero only at the beginning.
1109 * And we cannot overflow iter->next_index in a single step,
1110 * because RADIX_TREE_MAP_SHIFT < BITS_PER_LONG.
1112 * This condition also used by radix_tree_next_slot() to stop
1113 * contiguous iterating, and forbid swithing to the next chunk.
1115 index
= iter
->next_index
;
1116 if (!index
&& iter
->index
)
1120 radix_tree_load_root(root
, &child
, &maxindex
);
1121 if (index
> maxindex
)
1126 if (!radix_tree_is_internal_node(child
)) {
1127 /* Single-slot tree */
1128 iter
->index
= index
;
1129 iter
->next_index
= maxindex
+ 1;
1131 __set_iter_shift(iter
, 0);
1132 return (void **)&root
->rnode
;
1136 node
= entry_to_node(child
);
1137 offset
= radix_tree_descend(node
, &child
, index
);
1139 if ((flags
& RADIX_TREE_ITER_TAGGED
) ?
1140 !tag_get(node
, tag
, offset
) : !child
) {
1142 if (flags
& RADIX_TREE_ITER_CONTIG
)
1145 if (flags
& RADIX_TREE_ITER_TAGGED
)
1146 offset
= radix_tree_find_next_bit(
1148 RADIX_TREE_MAP_SIZE
,
1151 while (++offset
< RADIX_TREE_MAP_SIZE
) {
1152 void *slot
= node
->slots
[offset
];
1153 if (is_sibling_entry(node
, slot
))
1158 index
&= ~node_maxindex(node
);
1159 index
+= offset
<< node
->shift
;
1160 /* Overflow after ~0UL */
1163 if (offset
== RADIX_TREE_MAP_SIZE
)
1165 child
= rcu_dereference_raw(node
->slots
[offset
]);
1168 if ((child
== NULL
) || (child
== RADIX_TREE_RETRY
))
1170 } while (radix_tree_is_internal_node(child
));
1172 /* Update the iterator state */
1173 iter
->index
= (index
&~ node_maxindex(node
)) | (offset
<< node
->shift
);
1174 iter
->next_index
= (index
| node_maxindex(node
)) + 1;
1175 __set_iter_shift(iter
, node
->shift
);
1177 /* Construct iter->tags bit-mask from node->tags[tag] array */
1178 if (flags
& RADIX_TREE_ITER_TAGGED
) {
1179 unsigned tag_long
, tag_bit
;
1181 tag_long
= offset
/ BITS_PER_LONG
;
1182 tag_bit
= offset
% BITS_PER_LONG
;
1183 iter
->tags
= node
->tags
[tag
][tag_long
] >> tag_bit
;
1184 /* This never happens if RADIX_TREE_TAG_LONGS == 1 */
1185 if (tag_long
< RADIX_TREE_TAG_LONGS
- 1) {
1186 /* Pick tags from next element */
1188 iter
->tags
|= node
->tags
[tag
][tag_long
+ 1] <<
1189 (BITS_PER_LONG
- tag_bit
);
1190 /* Clip chunk size, here only BITS_PER_LONG tags */
1191 iter
->next_index
= index
+ BITS_PER_LONG
;
1195 return node
->slots
+ offset
;
1197 EXPORT_SYMBOL(radix_tree_next_chunk
);
1200 * radix_tree_range_tag_if_tagged - for each item in given range set given
1201 * tag if item has another tag set
1202 * @root: radix tree root
1203 * @first_indexp: pointer to a starting index of a range to scan
1204 * @last_index: last index of a range to scan
1205 * @nr_to_tag: maximum number items to tag
1206 * @iftag: tag index to test
1207 * @settag: tag index to set if tested tag is set
1209 * This function scans range of radix tree from first_index to last_index
1210 * (inclusive). For each item in the range if iftag is set, the function sets
1211 * also settag. The function stops either after tagging nr_to_tag items or
1212 * after reaching last_index.
1214 * The tags must be set from the leaf level only and propagated back up the
1215 * path to the root. We must do this so that we resolve the full path before
1216 * setting any tags on intermediate nodes. If we set tags as we descend, then
1217 * we can get to the leaf node and find that the index that has the iftag
1218 * set is outside the range we are scanning. This reults in dangling tags and
1219 * can lead to problems with later tag operations (e.g. livelocks on lookups).
1221 * The function returns the number of leaves where the tag was set and sets
1222 * *first_indexp to the first unscanned index.
1223 * WARNING! *first_indexp can wrap if last_index is ULONG_MAX. Caller must
1224 * be prepared to handle that.
1226 unsigned long radix_tree_range_tag_if_tagged(struct radix_tree_root
*root
,
1227 unsigned long *first_indexp
, unsigned long last_index
,
1228 unsigned long nr_to_tag
,
1229 unsigned int iftag
, unsigned int settag
)
1231 struct radix_tree_node
*parent
, *node
, *child
;
1232 unsigned long maxindex
;
1233 unsigned long tagged
= 0;
1234 unsigned long index
= *first_indexp
;
1236 radix_tree_load_root(root
, &child
, &maxindex
);
1237 last_index
= min(last_index
, maxindex
);
1238 if (index
> last_index
)
1242 if (!root_tag_get(root
, iftag
)) {
1243 *first_indexp
= last_index
+ 1;
1246 if (!radix_tree_is_internal_node(child
)) {
1247 *first_indexp
= last_index
+ 1;
1248 root_tag_set(root
, settag
);
1252 node
= entry_to_node(child
);
1255 unsigned offset
= radix_tree_descend(node
, &child
, index
);
1258 if (!tag_get(node
, iftag
, offset
))
1260 /* Sibling slots never have tags set on them */
1261 if (radix_tree_is_internal_node(child
)) {
1262 node
= entry_to_node(child
);
1268 tag_set(node
, settag
, offset
);
1270 /* walk back up the path tagging interior nodes */
1273 offset
= parent
->offset
;
1274 parent
= parent
->parent
;
1277 /* stop if we find a node with the tag already set */
1278 if (tag_get(parent
, settag
, offset
))
1280 tag_set(parent
, settag
, offset
);
1283 /* Go to next entry in node */
1284 index
= ((index
>> node
->shift
) + 1) << node
->shift
;
1285 /* Overflow can happen when last_index is ~0UL... */
1286 if (index
> last_index
|| !index
)
1288 offset
= (index
>> node
->shift
) & RADIX_TREE_MAP_MASK
;
1289 while (offset
== 0) {
1291 * We've fully scanned this node. Go up. Because
1292 * last_index is guaranteed to be in the tree, what
1293 * we do below cannot wander astray.
1295 node
= node
->parent
;
1296 offset
= (index
>> node
->shift
) & RADIX_TREE_MAP_MASK
;
1298 if (is_sibling_entry(node
, node
->slots
[offset
]))
1300 if (tagged
>= nr_to_tag
)
1304 * We need not to tag the root tag if there is no tag which is set with
1305 * settag within the range from *first_indexp to last_index.
1308 root_tag_set(root
, settag
);
1309 *first_indexp
= index
;
1313 EXPORT_SYMBOL(radix_tree_range_tag_if_tagged
);
1316 * radix_tree_gang_lookup - perform multiple lookup on a radix tree
1317 * @root: radix tree root
1318 * @results: where the results of the lookup are placed
1319 * @first_index: start the lookup from this key
1320 * @max_items: place up to this many items at *results
1322 * Performs an index-ascending scan of the tree for present items. Places
1323 * them at *@results and returns the number of items which were placed at
1326 * The implementation is naive.
1328 * Like radix_tree_lookup, radix_tree_gang_lookup may be called under
1329 * rcu_read_lock. In this case, rather than the returned results being
1330 * an atomic snapshot of the tree at a single point in time, the
1331 * semantics of an RCU protected gang lookup are as though multiple
1332 * radix_tree_lookups have been issued in individual locks, and results
1333 * stored in 'results'.
1336 radix_tree_gang_lookup(struct radix_tree_root
*root
, void **results
,
1337 unsigned long first_index
, unsigned int max_items
)
1339 struct radix_tree_iter iter
;
1341 unsigned int ret
= 0;
1343 if (unlikely(!max_items
))
1346 radix_tree_for_each_slot(slot
, root
, &iter
, first_index
) {
1347 results
[ret
] = rcu_dereference_raw(*slot
);
1350 if (radix_tree_is_internal_node(results
[ret
])) {
1351 slot
= radix_tree_iter_retry(&iter
);
1354 if (++ret
== max_items
)
1360 EXPORT_SYMBOL(radix_tree_gang_lookup
);
1363 * radix_tree_gang_lookup_slot - perform multiple slot lookup on radix tree
1364 * @root: radix tree root
1365 * @results: where the results of the lookup are placed
1366 * @indices: where their indices should be placed (but usually NULL)
1367 * @first_index: start the lookup from this key
1368 * @max_items: place up to this many items at *results
1370 * Performs an index-ascending scan of the tree for present items. Places
1371 * their slots at *@results and returns the number of items which were
1372 * placed at *@results.
1374 * The implementation is naive.
1376 * Like radix_tree_gang_lookup as far as RCU and locking goes. Slots must
1377 * be dereferenced with radix_tree_deref_slot, and if using only RCU
1378 * protection, radix_tree_deref_slot may fail requiring a retry.
1381 radix_tree_gang_lookup_slot(struct radix_tree_root
*root
,
1382 void ***results
, unsigned long *indices
,
1383 unsigned long first_index
, unsigned int max_items
)
1385 struct radix_tree_iter iter
;
1387 unsigned int ret
= 0;
1389 if (unlikely(!max_items
))
1392 radix_tree_for_each_slot(slot
, root
, &iter
, first_index
) {
1393 results
[ret
] = slot
;
1395 indices
[ret
] = iter
.index
;
1396 if (++ret
== max_items
)
1402 EXPORT_SYMBOL(radix_tree_gang_lookup_slot
);
1405 * radix_tree_gang_lookup_tag - perform multiple lookup on a radix tree
1407 * @root: radix tree root
1408 * @results: where the results of the lookup are placed
1409 * @first_index: start the lookup from this key
1410 * @max_items: place up to this many items at *results
1411 * @tag: the tag index (< RADIX_TREE_MAX_TAGS)
1413 * Performs an index-ascending scan of the tree for present items which
1414 * have the tag indexed by @tag set. Places the items at *@results and
1415 * returns the number of items which were placed at *@results.
1418 radix_tree_gang_lookup_tag(struct radix_tree_root
*root
, void **results
,
1419 unsigned long first_index
, unsigned int max_items
,
1422 struct radix_tree_iter iter
;
1424 unsigned int ret
= 0;
1426 if (unlikely(!max_items
))
1429 radix_tree_for_each_tagged(slot
, root
, &iter
, first_index
, tag
) {
1430 results
[ret
] = rcu_dereference_raw(*slot
);
1433 if (radix_tree_is_internal_node(results
[ret
])) {
1434 slot
= radix_tree_iter_retry(&iter
);
1437 if (++ret
== max_items
)
1443 EXPORT_SYMBOL(radix_tree_gang_lookup_tag
);
1446 * radix_tree_gang_lookup_tag_slot - perform multiple slot lookup on a
1447 * radix tree based on a tag
1448 * @root: radix tree root
1449 * @results: where the results of the lookup are placed
1450 * @first_index: start the lookup from this key
1451 * @max_items: place up to this many items at *results
1452 * @tag: the tag index (< RADIX_TREE_MAX_TAGS)
1454 * Performs an index-ascending scan of the tree for present items which
1455 * have the tag indexed by @tag set. Places the slots at *@results and
1456 * returns the number of slots which were placed at *@results.
1459 radix_tree_gang_lookup_tag_slot(struct radix_tree_root
*root
, void ***results
,
1460 unsigned long first_index
, unsigned int max_items
,
1463 struct radix_tree_iter iter
;
1465 unsigned int ret
= 0;
1467 if (unlikely(!max_items
))
1470 radix_tree_for_each_tagged(slot
, root
, &iter
, first_index
, tag
) {
1471 results
[ret
] = slot
;
1472 if (++ret
== max_items
)
1478 EXPORT_SYMBOL(radix_tree_gang_lookup_tag_slot
);
1480 #if defined(CONFIG_SHMEM) && defined(CONFIG_SWAP)
1481 #include <linux/sched.h> /* for cond_resched() */
1483 struct locate_info
{
1484 unsigned long found_index
;
1489 * This linear search is at present only useful to shmem_unuse_inode().
1491 static unsigned long __locate(struct radix_tree_node
*slot
, void *item
,
1492 unsigned long index
, struct locate_info
*info
)
1497 unsigned int shift
= slot
->shift
;
1499 for (i
= (index
>> shift
) & RADIX_TREE_MAP_MASK
;
1500 i
< RADIX_TREE_MAP_SIZE
;
1501 i
++, index
+= (1UL << shift
)) {
1502 struct radix_tree_node
*node
=
1503 rcu_dereference_raw(slot
->slots
[i
]);
1504 if (node
== RADIX_TREE_RETRY
)
1506 if (!radix_tree_is_internal_node(node
)) {
1508 info
->found_index
= index
;
1514 node
= entry_to_node(node
);
1515 if (is_sibling_entry(slot
, node
))
1520 } while (i
< RADIX_TREE_MAP_SIZE
);
1523 if ((index
== 0) && (i
== RADIX_TREE_MAP_SIZE
))
1529 * radix_tree_locate_item - search through radix tree for item
1530 * @root: radix tree root
1531 * @item: item to be found
1533 * Returns index where item was found, or -1 if not found.
1534 * Caller must hold no lock (since this time-consuming function needs
1535 * to be preemptible), and must check afterwards if item is still there.
1537 unsigned long radix_tree_locate_item(struct radix_tree_root
*root
, void *item
)
1539 struct radix_tree_node
*node
;
1540 unsigned long max_index
;
1541 unsigned long cur_index
= 0;
1542 struct locate_info info
= {
1549 node
= rcu_dereference_raw(root
->rnode
);
1550 if (!radix_tree_is_internal_node(node
)) {
1553 info
.found_index
= 0;
1557 node
= entry_to_node(node
);
1559 max_index
= node_maxindex(node
);
1560 if (cur_index
> max_index
) {
1565 cur_index
= __locate(node
, item
, cur_index
, &info
);
1568 } while (!info
.stop
&& cur_index
<= max_index
);
1570 return info
.found_index
;
1573 unsigned long radix_tree_locate_item(struct radix_tree_root
*root
, void *item
)
1577 #endif /* CONFIG_SHMEM && CONFIG_SWAP */
1580 * __radix_tree_delete_node - try to free node after clearing a slot
1581 * @root: radix tree root
1582 * @node: node containing @index
1584 * After clearing the slot at @index in @node from radix tree
1585 * rooted at @root, call this function to attempt freeing the
1586 * node and shrinking the tree.
1588 void __radix_tree_delete_node(struct radix_tree_root
*root
,
1589 struct radix_tree_node
*node
)
1591 delete_node(root
, node
, NULL
, NULL
);
1594 static inline void delete_sibling_entries(struct radix_tree_node
*node
,
1595 void *ptr
, unsigned offset
)
1597 #ifdef CONFIG_RADIX_TREE_MULTIORDER
1599 for (i
= 1; offset
+ i
< RADIX_TREE_MAP_SIZE
; i
++) {
1600 if (node
->slots
[offset
+ i
] != ptr
)
1602 node
->slots
[offset
+ i
] = NULL
;
1609 * radix_tree_delete_item - delete an item from a radix tree
1610 * @root: radix tree root
1612 * @item: expected item
1614 * Remove @item at @index from the radix tree rooted at @root.
1616 * Returns the address of the deleted item, or NULL if it was not present
1617 * or the entry at the given @index was not @item.
1619 void *radix_tree_delete_item(struct radix_tree_root
*root
,
1620 unsigned long index
, void *item
)
1622 struct radix_tree_node
*node
;
1623 unsigned int offset
;
1628 entry
= __radix_tree_lookup(root
, index
, &node
, &slot
);
1632 if (item
&& entry
!= item
)
1636 root_tag_clear_all(root
);
1641 offset
= get_slot_offset(node
, slot
);
1643 /* Clear all tags associated with the item to be deleted. */
1644 for (tag
= 0; tag
< RADIX_TREE_MAX_TAGS
; tag
++)
1645 node_tag_clear(root
, node
, tag
, offset
);
1647 delete_sibling_entries(node
, node_to_entry(slot
), offset
);
1648 __radix_tree_replace(root
, node
, slot
, NULL
, NULL
, NULL
);
1652 EXPORT_SYMBOL(radix_tree_delete_item
);
1655 * radix_tree_delete - delete an item from a radix tree
1656 * @root: radix tree root
1659 * Remove the item at @index from the radix tree rooted at @root.
1661 * Returns the address of the deleted item, or NULL if it was not present.
1663 void *radix_tree_delete(struct radix_tree_root
*root
, unsigned long index
)
1665 return radix_tree_delete_item(root
, index
, NULL
);
1667 EXPORT_SYMBOL(radix_tree_delete
);
1669 void radix_tree_clear_tags(struct radix_tree_root
*root
,
1670 struct radix_tree_node
*node
,
1674 unsigned int tag
, offset
= get_slot_offset(node
, slot
);
1675 for (tag
= 0; tag
< RADIX_TREE_MAX_TAGS
; tag
++)
1676 node_tag_clear(root
, node
, tag
, offset
);
1678 /* Clear root node tags */
1679 root
->gfp_mask
&= __GFP_BITS_MASK
;
1684 * radix_tree_tagged - test whether any items in the tree are tagged
1685 * @root: radix tree root
1688 int radix_tree_tagged(struct radix_tree_root
*root
, unsigned int tag
)
1690 return root_tag_get(root
, tag
);
1692 EXPORT_SYMBOL(radix_tree_tagged
);
1695 radix_tree_node_ctor(void *arg
)
1697 struct radix_tree_node
*node
= arg
;
1699 memset(node
, 0, sizeof(*node
));
1700 INIT_LIST_HEAD(&node
->private_list
);
1703 static __init
unsigned long __maxindex(unsigned int height
)
1705 unsigned int width
= height
* RADIX_TREE_MAP_SHIFT
;
1706 int shift
= RADIX_TREE_INDEX_BITS
- width
;
1710 if (shift
>= BITS_PER_LONG
)
1712 return ~0UL >> shift
;
1715 static __init
void radix_tree_init_maxnodes(void)
1717 unsigned long height_to_maxindex
[RADIX_TREE_MAX_PATH
+ 1];
1720 for (i
= 0; i
< ARRAY_SIZE(height_to_maxindex
); i
++)
1721 height_to_maxindex
[i
] = __maxindex(i
);
1722 for (i
= 0; i
< ARRAY_SIZE(height_to_maxnodes
); i
++) {
1723 for (j
= i
; j
> 0; j
--)
1724 height_to_maxnodes
[i
] += height_to_maxindex
[j
- 1] + 1;
1728 static int radix_tree_cpu_dead(unsigned int cpu
)
1730 struct radix_tree_preload
*rtp
;
1731 struct radix_tree_node
*node
;
1733 /* Free per-cpu pool of preloaded nodes */
1734 rtp
= &per_cpu(radix_tree_preloads
, cpu
);
1737 rtp
->nodes
= node
->private_data
;
1738 kmem_cache_free(radix_tree_node_cachep
, node
);
1744 void __init
radix_tree_init(void)
1747 radix_tree_node_cachep
= kmem_cache_create("radix_tree_node",
1748 sizeof(struct radix_tree_node
), 0,
1749 SLAB_PANIC
| SLAB_RECLAIM_ACCOUNT
,
1750 radix_tree_node_ctor
);
1751 radix_tree_init_maxnodes();
1752 ret
= cpuhp_setup_state_nocalls(CPUHP_RADIX_DEAD
, "lib/radix:dead",
1753 NULL
, radix_tree_cpu_dead
);