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![Matthew Wilcox (Oracle)](/assets/img/avatar_default.png)
[ Upstream commit b7e9728f3d
]
Attempting to allocate an entry at 0xffffffff when one is already
present would succeed in allocating one at 2^32, which would confuse
everything. Return -ENOSPC in this case, as expected.
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
2299 lines
62 KiB
C
2299 lines
62 KiB
C
/*
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* Copyright (C) 2001 Momchil Velikov
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* Portions Copyright (C) 2001 Christoph Hellwig
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* Copyright (C) 2005 SGI, Christoph Lameter
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* Copyright (C) 2006 Nick Piggin
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* Copyright (C) 2012 Konstantin Khlebnikov
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* Copyright (C) 2016 Intel, Matthew Wilcox
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* Copyright (C) 2016 Intel, Ross Zwisler
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License as
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* published by the Free Software Foundation; either version 2, or (at
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* your option) any later version.
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*
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* This program is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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*/
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#include <linux/bitmap.h>
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#include <linux/bitops.h>
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#include <linux/cpu.h>
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#include <linux/errno.h>
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#include <linux/export.h>
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#include <linux/idr.h>
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#include <linux/init.h>
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#include <linux/kernel.h>
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#include <linux/kmemleak.h>
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#include <linux/percpu.h>
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#include <linux/preempt.h> /* in_interrupt() */
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#include <linux/radix-tree.h>
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#include <linux/rcupdate.h>
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#include <linux/slab.h>
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#include <linux/string.h>
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/* Number of nodes in fully populated tree of given height */
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static unsigned long height_to_maxnodes[RADIX_TREE_MAX_PATH + 1] __read_mostly;
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/*
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* Radix tree node cache.
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*/
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static struct kmem_cache *radix_tree_node_cachep;
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/*
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* The radix tree is variable-height, so an insert operation not only has
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* to build the branch to its corresponding item, it also has to build the
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* branch to existing items if the size has to be increased (by
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* radix_tree_extend).
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*
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* The worst case is a zero height tree with just a single item at index 0,
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* and then inserting an item at index ULONG_MAX. This requires 2 new branches
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* of RADIX_TREE_MAX_PATH size to be created, with only the root node shared.
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* Hence:
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*/
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#define RADIX_TREE_PRELOAD_SIZE (RADIX_TREE_MAX_PATH * 2 - 1)
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/*
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* The IDR does not have to be as high as the radix tree since it uses
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* signed integers, not unsigned longs.
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*/
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#define IDR_INDEX_BITS (8 /* CHAR_BIT */ * sizeof(int) - 1)
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#define IDR_MAX_PATH (DIV_ROUND_UP(IDR_INDEX_BITS, \
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RADIX_TREE_MAP_SHIFT))
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#define IDR_PRELOAD_SIZE (IDR_MAX_PATH * 2 - 1)
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/*
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* The IDA is even shorter since it uses a bitmap at the last level.
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*/
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#define IDA_INDEX_BITS (8 * sizeof(int) - 1 - ilog2(IDA_BITMAP_BITS))
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#define IDA_MAX_PATH (DIV_ROUND_UP(IDA_INDEX_BITS, \
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RADIX_TREE_MAP_SHIFT))
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#define IDA_PRELOAD_SIZE (IDA_MAX_PATH * 2 - 1)
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/*
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* Per-cpu pool of preloaded nodes
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*/
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struct radix_tree_preload {
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unsigned nr;
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/* nodes->parent points to next preallocated node */
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struct radix_tree_node *nodes;
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};
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static DEFINE_PER_CPU(struct radix_tree_preload, radix_tree_preloads) = { 0, };
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static inline struct radix_tree_node *entry_to_node(void *ptr)
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{
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return (void *)((unsigned long)ptr & ~RADIX_TREE_INTERNAL_NODE);
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}
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static inline void *node_to_entry(void *ptr)
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{
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return (void *)((unsigned long)ptr | RADIX_TREE_INTERNAL_NODE);
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}
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#define RADIX_TREE_RETRY node_to_entry(NULL)
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#ifdef CONFIG_RADIX_TREE_MULTIORDER
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/* Sibling slots point directly to another slot in the same node */
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static inline
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bool is_sibling_entry(const struct radix_tree_node *parent, void *node)
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{
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void __rcu **ptr = node;
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return (parent->slots <= ptr) &&
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(ptr < parent->slots + RADIX_TREE_MAP_SIZE);
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}
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#else
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static inline
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bool is_sibling_entry(const struct radix_tree_node *parent, void *node)
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{
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return false;
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}
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#endif
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static inline unsigned long
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get_slot_offset(const struct radix_tree_node *parent, void __rcu **slot)
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{
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return slot - parent->slots;
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}
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static unsigned int radix_tree_descend(const struct radix_tree_node *parent,
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struct radix_tree_node **nodep, unsigned long index)
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{
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unsigned int offset = (index >> parent->shift) & RADIX_TREE_MAP_MASK;
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void __rcu **entry = rcu_dereference_raw(parent->slots[offset]);
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#ifdef CONFIG_RADIX_TREE_MULTIORDER
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if (radix_tree_is_internal_node(entry)) {
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if (is_sibling_entry(parent, entry)) {
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void __rcu **sibentry;
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sibentry = (void __rcu **) entry_to_node(entry);
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offset = get_slot_offset(parent, sibentry);
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entry = rcu_dereference_raw(*sibentry);
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}
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}
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#endif
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*nodep = (void *)entry;
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return offset;
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}
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static inline gfp_t root_gfp_mask(const struct radix_tree_root *root)
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{
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return root->gfp_mask & __GFP_BITS_MASK;
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}
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static inline void tag_set(struct radix_tree_node *node, unsigned int tag,
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int offset)
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{
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__set_bit(offset, node->tags[tag]);
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}
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static inline void tag_clear(struct radix_tree_node *node, unsigned int tag,
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int offset)
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{
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__clear_bit(offset, node->tags[tag]);
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}
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static inline int tag_get(const struct radix_tree_node *node, unsigned int tag,
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int offset)
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{
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return test_bit(offset, node->tags[tag]);
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}
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static inline void root_tag_set(struct radix_tree_root *root, unsigned tag)
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{
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root->gfp_mask |= (__force gfp_t)(1 << (tag + ROOT_TAG_SHIFT));
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}
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static inline void root_tag_clear(struct radix_tree_root *root, unsigned tag)
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{
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root->gfp_mask &= (__force gfp_t)~(1 << (tag + ROOT_TAG_SHIFT));
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}
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static inline void root_tag_clear_all(struct radix_tree_root *root)
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{
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root->gfp_mask &= (1 << ROOT_TAG_SHIFT) - 1;
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}
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static inline int root_tag_get(const struct radix_tree_root *root, unsigned tag)
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{
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return (__force int)root->gfp_mask & (1 << (tag + ROOT_TAG_SHIFT));
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}
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static inline unsigned root_tags_get(const struct radix_tree_root *root)
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{
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return (__force unsigned)root->gfp_mask >> ROOT_TAG_SHIFT;
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}
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static inline bool is_idr(const struct radix_tree_root *root)
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{
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return !!(root->gfp_mask & ROOT_IS_IDR);
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}
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/*
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* Returns 1 if any slot in the node has this tag set.
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* Otherwise returns 0.
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*/
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static inline int any_tag_set(const struct radix_tree_node *node,
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unsigned int tag)
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{
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unsigned idx;
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for (idx = 0; idx < RADIX_TREE_TAG_LONGS; idx++) {
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if (node->tags[tag][idx])
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return 1;
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}
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return 0;
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}
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static inline void all_tag_set(struct radix_tree_node *node, unsigned int tag)
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{
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bitmap_fill(node->tags[tag], RADIX_TREE_MAP_SIZE);
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}
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/**
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* radix_tree_find_next_bit - find the next set bit in a memory region
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*
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* @addr: The address to base the search on
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* @size: The bitmap size in bits
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* @offset: The bitnumber to start searching at
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*
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* Unrollable variant of find_next_bit() for constant size arrays.
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* Tail bits starting from size to roundup(size, BITS_PER_LONG) must be zero.
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* Returns next bit offset, or size if nothing found.
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*/
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static __always_inline unsigned long
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radix_tree_find_next_bit(struct radix_tree_node *node, unsigned int tag,
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unsigned long offset)
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{
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const unsigned long *addr = node->tags[tag];
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if (offset < RADIX_TREE_MAP_SIZE) {
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unsigned long tmp;
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addr += offset / BITS_PER_LONG;
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tmp = *addr >> (offset % BITS_PER_LONG);
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if (tmp)
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return __ffs(tmp) + offset;
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offset = (offset + BITS_PER_LONG) & ~(BITS_PER_LONG - 1);
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while (offset < RADIX_TREE_MAP_SIZE) {
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tmp = *++addr;
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if (tmp)
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return __ffs(tmp) + offset;
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offset += BITS_PER_LONG;
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}
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}
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return RADIX_TREE_MAP_SIZE;
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}
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static unsigned int iter_offset(const struct radix_tree_iter *iter)
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{
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return (iter->index >> iter_shift(iter)) & RADIX_TREE_MAP_MASK;
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}
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/*
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* The maximum index which can be stored in a radix tree
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*/
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static inline unsigned long shift_maxindex(unsigned int shift)
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{
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return (RADIX_TREE_MAP_SIZE << shift) - 1;
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}
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static inline unsigned long node_maxindex(const struct radix_tree_node *node)
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{
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return shift_maxindex(node->shift);
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}
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static unsigned long next_index(unsigned long index,
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const struct radix_tree_node *node,
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unsigned long offset)
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{
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return (index & ~node_maxindex(node)) + (offset << node->shift);
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}
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#ifndef __KERNEL__
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static void dump_node(struct radix_tree_node *node, unsigned long index)
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{
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unsigned long i;
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pr_debug("radix node: %p offset %d indices %lu-%lu parent %p tags %lx %lx %lx shift %d count %d exceptional %d\n",
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node, node->offset, index, index | node_maxindex(node),
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node->parent,
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node->tags[0][0], node->tags[1][0], node->tags[2][0],
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node->shift, node->count, node->exceptional);
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for (i = 0; i < RADIX_TREE_MAP_SIZE; i++) {
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unsigned long first = index | (i << node->shift);
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unsigned long last = first | ((1UL << node->shift) - 1);
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void *entry = node->slots[i];
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if (!entry)
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continue;
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if (entry == RADIX_TREE_RETRY) {
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pr_debug("radix retry offset %ld indices %lu-%lu parent %p\n",
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i, first, last, node);
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} else if (!radix_tree_is_internal_node(entry)) {
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pr_debug("radix entry %p offset %ld indices %lu-%lu parent %p\n",
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entry, i, first, last, node);
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} else if (is_sibling_entry(node, entry)) {
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pr_debug("radix sblng %p offset %ld indices %lu-%lu parent %p val %p\n",
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entry, i, first, last, node,
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*(void **)entry_to_node(entry));
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} else {
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dump_node(entry_to_node(entry), first);
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}
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}
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}
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/* For debug */
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static void radix_tree_dump(struct radix_tree_root *root)
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{
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pr_debug("radix root: %p rnode %p tags %x\n",
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root, root->rnode,
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root->gfp_mask >> ROOT_TAG_SHIFT);
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if (!radix_tree_is_internal_node(root->rnode))
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return;
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dump_node(entry_to_node(root->rnode), 0);
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}
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static void dump_ida_node(void *entry, unsigned long index)
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{
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unsigned long i;
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if (!entry)
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return;
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if (radix_tree_is_internal_node(entry)) {
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struct radix_tree_node *node = entry_to_node(entry);
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pr_debug("ida node: %p offset %d indices %lu-%lu parent %p free %lx shift %d count %d\n",
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node, node->offset, index * IDA_BITMAP_BITS,
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((index | node_maxindex(node)) + 1) *
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IDA_BITMAP_BITS - 1,
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node->parent, node->tags[0][0], node->shift,
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node->count);
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for (i = 0; i < RADIX_TREE_MAP_SIZE; i++)
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dump_ida_node(node->slots[i],
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index | (i << node->shift));
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} else if (radix_tree_exceptional_entry(entry)) {
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pr_debug("ida excp: %p offset %d indices %lu-%lu data %lx\n",
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entry, (int)(index & RADIX_TREE_MAP_MASK),
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index * IDA_BITMAP_BITS,
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index * IDA_BITMAP_BITS + BITS_PER_LONG -
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RADIX_TREE_EXCEPTIONAL_SHIFT,
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(unsigned long)entry >>
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RADIX_TREE_EXCEPTIONAL_SHIFT);
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} else {
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struct ida_bitmap *bitmap = entry;
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pr_debug("ida btmp: %p offset %d indices %lu-%lu data", bitmap,
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(int)(index & RADIX_TREE_MAP_MASK),
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index * IDA_BITMAP_BITS,
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(index + 1) * IDA_BITMAP_BITS - 1);
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for (i = 0; i < IDA_BITMAP_LONGS; i++)
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pr_cont(" %lx", bitmap->bitmap[i]);
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pr_cont("\n");
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}
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}
|
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static void ida_dump(struct ida *ida)
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{
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struct radix_tree_root *root = &ida->ida_rt;
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pr_debug("ida: %p node %p free %d\n", ida, root->rnode,
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root->gfp_mask >> ROOT_TAG_SHIFT);
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dump_ida_node(root->rnode, 0);
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}
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#endif
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|
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/*
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* This assumes that the caller has performed appropriate preallocation, and
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* that the caller has pinned this thread of control to the current CPU.
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*/
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static struct radix_tree_node *
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radix_tree_node_alloc(gfp_t gfp_mask, struct radix_tree_node *parent,
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struct radix_tree_root *root,
|
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unsigned int shift, unsigned int offset,
|
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unsigned int count, unsigned int exceptional)
|
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{
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struct radix_tree_node *ret = NULL;
|
|
|
|
/*
|
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* Preload code isn't irq safe and it doesn't make sense to use
|
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* preloading during an interrupt anyway as all the allocations have
|
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* to be atomic. So just do normal allocation when in interrupt.
|
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*/
|
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if (!gfpflags_allow_blocking(gfp_mask) && !in_interrupt()) {
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struct radix_tree_preload *rtp;
|
|
|
|
/*
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* Even if the caller has preloaded, try to allocate from the
|
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* cache first for the new node to get accounted to the memory
|
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* cgroup.
|
|
*/
|
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ret = kmem_cache_alloc(radix_tree_node_cachep,
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gfp_mask | __GFP_NOWARN);
|
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if (ret)
|
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goto out;
|
|
|
|
/*
|
|
* Provided the caller has preloaded here, we will always
|
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* succeed in getting a node here (and never reach
|
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* kmem_cache_alloc)
|
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*/
|
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rtp = this_cpu_ptr(&radix_tree_preloads);
|
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if (rtp->nr) {
|
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ret = rtp->nodes;
|
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rtp->nodes = ret->parent;
|
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rtp->nr--;
|
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}
|
|
/*
|
|
* Update the allocation stack trace as this is more useful
|
|
* for debugging.
|
|
*/
|
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kmemleak_update_trace(ret);
|
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goto out;
|
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}
|
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ret = kmem_cache_alloc(radix_tree_node_cachep, gfp_mask);
|
|
out:
|
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BUG_ON(radix_tree_is_internal_node(ret));
|
|
if (ret) {
|
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ret->shift = shift;
|
|
ret->offset = offset;
|
|
ret->count = count;
|
|
ret->exceptional = exceptional;
|
|
ret->parent = parent;
|
|
ret->root = root;
|
|
}
|
|
return ret;
|
|
}
|
|
|
|
static void radix_tree_node_rcu_free(struct rcu_head *head)
|
|
{
|
|
struct radix_tree_node *node =
|
|
container_of(head, struct radix_tree_node, rcu_head);
|
|
|
|
/*
|
|
* Must only free zeroed nodes into the slab. We can be left with
|
|
* non-NULL entries by radix_tree_free_nodes, so clear the entries
|
|
* and tags here.
|
|
*/
|
|
memset(node->slots, 0, sizeof(node->slots));
|
|
memset(node->tags, 0, sizeof(node->tags));
|
|
INIT_LIST_HEAD(&node->private_list);
|
|
|
|
kmem_cache_free(radix_tree_node_cachep, node);
|
|
}
|
|
|
|
static inline void
|
|
radix_tree_node_free(struct radix_tree_node *node)
|
|
{
|
|
call_rcu(&node->rcu_head, radix_tree_node_rcu_free);
|
|
}
|
|
|
|
/*
|
|
* Load up this CPU's radix_tree_node buffer with sufficient objects to
|
|
* ensure that the addition of a single element in the tree cannot fail. On
|
|
* success, return zero, with preemption disabled. On error, return -ENOMEM
|
|
* with preemption not disabled.
|
|
*
|
|
* To make use of this facility, the radix tree must be initialised without
|
|
* __GFP_DIRECT_RECLAIM being passed to INIT_RADIX_TREE().
|
|
*/
|
|
static __must_check int __radix_tree_preload(gfp_t gfp_mask, unsigned nr)
|
|
{
|
|
struct radix_tree_preload *rtp;
|
|
struct radix_tree_node *node;
|
|
int ret = -ENOMEM;
|
|
|
|
/*
|
|
* Nodes preloaded by one cgroup can be be used by another cgroup, so
|
|
* they should never be accounted to any particular memory cgroup.
|
|
*/
|
|
gfp_mask &= ~__GFP_ACCOUNT;
|
|
|
|
preempt_disable();
|
|
rtp = this_cpu_ptr(&radix_tree_preloads);
|
|
while (rtp->nr < nr) {
|
|
preempt_enable();
|
|
node = kmem_cache_alloc(radix_tree_node_cachep, gfp_mask);
|
|
if (node == NULL)
|
|
goto out;
|
|
preempt_disable();
|
|
rtp = this_cpu_ptr(&radix_tree_preloads);
|
|
if (rtp->nr < nr) {
|
|
node->parent = rtp->nodes;
|
|
rtp->nodes = node;
|
|
rtp->nr++;
|
|
} else {
|
|
kmem_cache_free(radix_tree_node_cachep, node);
|
|
}
|
|
}
|
|
ret = 0;
|
|
out:
|
|
return ret;
|
|
}
|
|
|
|
/*
|
|
* Load up this CPU's radix_tree_node buffer with sufficient objects to
|
|
* ensure that the addition of a single element in the tree cannot fail. On
|
|
* success, return zero, with preemption disabled. On error, return -ENOMEM
|
|
* with preemption not disabled.
|
|
*
|
|
* To make use of this facility, the radix tree must be initialised without
|
|
* __GFP_DIRECT_RECLAIM being passed to INIT_RADIX_TREE().
|
|
*/
|
|
int radix_tree_preload(gfp_t gfp_mask)
|
|
{
|
|
/* Warn on non-sensical use... */
|
|
WARN_ON_ONCE(!gfpflags_allow_blocking(gfp_mask));
|
|
return __radix_tree_preload(gfp_mask, RADIX_TREE_PRELOAD_SIZE);
|
|
}
|
|
EXPORT_SYMBOL(radix_tree_preload);
|
|
|
|
/*
|
|
* The same as above function, except we don't guarantee preloading happens.
|
|
* We do it, if we decide it helps. On success, return zero with preemption
|
|
* disabled. On error, return -ENOMEM with preemption not disabled.
|
|
*/
|
|
int radix_tree_maybe_preload(gfp_t gfp_mask)
|
|
{
|
|
if (gfpflags_allow_blocking(gfp_mask))
|
|
return __radix_tree_preload(gfp_mask, RADIX_TREE_PRELOAD_SIZE);
|
|
/* Preloading doesn't help anything with this gfp mask, skip it */
|
|
preempt_disable();
|
|
return 0;
|
|
}
|
|
EXPORT_SYMBOL(radix_tree_maybe_preload);
|
|
|
|
#ifdef CONFIG_RADIX_TREE_MULTIORDER
|
|
/*
|
|
* Preload with enough objects to ensure that we can split a single entry
|
|
* of order @old_order into many entries of size @new_order
|
|
*/
|
|
int radix_tree_split_preload(unsigned int old_order, unsigned int new_order,
|
|
gfp_t gfp_mask)
|
|
{
|
|
unsigned top = 1 << (old_order % RADIX_TREE_MAP_SHIFT);
|
|
unsigned layers = (old_order / RADIX_TREE_MAP_SHIFT) -
|
|
(new_order / RADIX_TREE_MAP_SHIFT);
|
|
unsigned nr = 0;
|
|
|
|
WARN_ON_ONCE(!gfpflags_allow_blocking(gfp_mask));
|
|
BUG_ON(new_order >= old_order);
|
|
|
|
while (layers--)
|
|
nr = nr * RADIX_TREE_MAP_SIZE + 1;
|
|
return __radix_tree_preload(gfp_mask, top * nr);
|
|
}
|
|
#endif
|
|
|
|
/*
|
|
* The same as function above, but preload number of nodes required to insert
|
|
* (1 << order) continuous naturally-aligned elements.
|
|
*/
|
|
int radix_tree_maybe_preload_order(gfp_t gfp_mask, int order)
|
|
{
|
|
unsigned long nr_subtrees;
|
|
int nr_nodes, subtree_height;
|
|
|
|
/* Preloading doesn't help anything with this gfp mask, skip it */
|
|
if (!gfpflags_allow_blocking(gfp_mask)) {
|
|
preempt_disable();
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* Calculate number and height of fully populated subtrees it takes to
|
|
* store (1 << order) elements.
|
|
*/
|
|
nr_subtrees = 1 << order;
|
|
for (subtree_height = 0; nr_subtrees > RADIX_TREE_MAP_SIZE;
|
|
subtree_height++)
|
|
nr_subtrees >>= RADIX_TREE_MAP_SHIFT;
|
|
|
|
/*
|
|
* The worst case is zero height tree with a single item at index 0 and
|
|
* then inserting items starting at ULONG_MAX - (1 << order).
|
|
*
|
|
* This requires RADIX_TREE_MAX_PATH nodes to build branch from root to
|
|
* 0-index item.
|
|
*/
|
|
nr_nodes = RADIX_TREE_MAX_PATH;
|
|
|
|
/* Plus branch to fully populated subtrees. */
|
|
nr_nodes += RADIX_TREE_MAX_PATH - subtree_height;
|
|
|
|
/* Root node is shared. */
|
|
nr_nodes--;
|
|
|
|
/* Plus nodes required to build subtrees. */
|
|
nr_nodes += nr_subtrees * height_to_maxnodes[subtree_height];
|
|
|
|
return __radix_tree_preload(gfp_mask, nr_nodes);
|
|
}
|
|
|
|
static unsigned radix_tree_load_root(const struct radix_tree_root *root,
|
|
struct radix_tree_node **nodep, unsigned long *maxindex)
|
|
{
|
|
struct radix_tree_node *node = rcu_dereference_raw(root->rnode);
|
|
|
|
*nodep = node;
|
|
|
|
if (likely(radix_tree_is_internal_node(node))) {
|
|
node = entry_to_node(node);
|
|
*maxindex = node_maxindex(node);
|
|
return node->shift + RADIX_TREE_MAP_SHIFT;
|
|
}
|
|
|
|
*maxindex = 0;
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* Extend a radix tree so it can store key @index.
|
|
*/
|
|
static int radix_tree_extend(struct radix_tree_root *root, gfp_t gfp,
|
|
unsigned long index, unsigned int shift)
|
|
{
|
|
void *entry;
|
|
unsigned int maxshift;
|
|
int tag;
|
|
|
|
/* Figure out what the shift should be. */
|
|
maxshift = shift;
|
|
while (index > shift_maxindex(maxshift))
|
|
maxshift += RADIX_TREE_MAP_SHIFT;
|
|
|
|
entry = rcu_dereference_raw(root->rnode);
|
|
if (!entry && (!is_idr(root) || root_tag_get(root, IDR_FREE)))
|
|
goto out;
|
|
|
|
do {
|
|
struct radix_tree_node *node = radix_tree_node_alloc(gfp, NULL,
|
|
root, shift, 0, 1, 0);
|
|
if (!node)
|
|
return -ENOMEM;
|
|
|
|
if (is_idr(root)) {
|
|
all_tag_set(node, IDR_FREE);
|
|
if (!root_tag_get(root, IDR_FREE)) {
|
|
tag_clear(node, IDR_FREE, 0);
|
|
root_tag_set(root, IDR_FREE);
|
|
}
|
|
} else {
|
|
/* Propagate the aggregated tag info to the new child */
|
|
for (tag = 0; tag < RADIX_TREE_MAX_TAGS; tag++) {
|
|
if (root_tag_get(root, tag))
|
|
tag_set(node, tag, 0);
|
|
}
|
|
}
|
|
|
|
BUG_ON(shift > BITS_PER_LONG);
|
|
if (radix_tree_is_internal_node(entry)) {
|
|
entry_to_node(entry)->parent = node;
|
|
} else if (radix_tree_exceptional_entry(entry)) {
|
|
/* Moving an exceptional root->rnode to a node */
|
|
node->exceptional = 1;
|
|
}
|
|
/*
|
|
* entry was already in the radix tree, so we do not need
|
|
* rcu_assign_pointer here
|
|
*/
|
|
node->slots[0] = (void __rcu *)entry;
|
|
entry = node_to_entry(node);
|
|
rcu_assign_pointer(root->rnode, entry);
|
|
shift += RADIX_TREE_MAP_SHIFT;
|
|
} while (shift <= maxshift);
|
|
out:
|
|
return maxshift + RADIX_TREE_MAP_SHIFT;
|
|
}
|
|
|
|
/**
|
|
* radix_tree_shrink - shrink radix tree to minimum height
|
|
* @root radix tree root
|
|
*/
|
|
static inline bool radix_tree_shrink(struct radix_tree_root *root,
|
|
radix_tree_update_node_t update_node,
|
|
void *private)
|
|
{
|
|
bool shrunk = false;
|
|
|
|
for (;;) {
|
|
struct radix_tree_node *node = rcu_dereference_raw(root->rnode);
|
|
struct radix_tree_node *child;
|
|
|
|
if (!radix_tree_is_internal_node(node))
|
|
break;
|
|
node = entry_to_node(node);
|
|
|
|
/*
|
|
* The candidate node has more than one child, or its child
|
|
* is not at the leftmost slot, or the child is a multiorder
|
|
* entry, we cannot shrink.
|
|
*/
|
|
if (node->count != 1)
|
|
break;
|
|
child = rcu_dereference_raw(node->slots[0]);
|
|
if (!child)
|
|
break;
|
|
if (!radix_tree_is_internal_node(child) && node->shift)
|
|
break;
|
|
|
|
if (radix_tree_is_internal_node(child))
|
|
entry_to_node(child)->parent = NULL;
|
|
|
|
/*
|
|
* We don't need rcu_assign_pointer(), since we are simply
|
|
* moving the node from one part of the tree to another: if it
|
|
* was safe to dereference the old pointer to it
|
|
* (node->slots[0]), it will be safe to dereference the new
|
|
* one (root->rnode) as far as dependent read barriers go.
|
|
*/
|
|
root->rnode = (void __rcu *)child;
|
|
if (is_idr(root) && !tag_get(node, IDR_FREE, 0))
|
|
root_tag_clear(root, IDR_FREE);
|
|
|
|
/*
|
|
* We have a dilemma here. The node's slot[0] must not be
|
|
* NULLed in case there are concurrent lookups expecting to
|
|
* find the item. However if this was a bottom-level node,
|
|
* then it may be subject to the slot pointer being visible
|
|
* to callers dereferencing it. If item corresponding to
|
|
* slot[0] is subsequently deleted, these callers would expect
|
|
* their slot to become empty sooner or later.
|
|
*
|
|
* For example, lockless pagecache will look up a slot, deref
|
|
* the page pointer, and if the page has 0 refcount it means it
|
|
* was concurrently deleted from pagecache so try the deref
|
|
* again. Fortunately there is already a requirement for logic
|
|
* to retry the entire slot lookup -- the indirect pointer
|
|
* problem (replacing direct root node with an indirect pointer
|
|
* also results in a stale slot). So tag the slot as indirect
|
|
* to force callers to retry.
|
|
*/
|
|
node->count = 0;
|
|
if (!radix_tree_is_internal_node(child)) {
|
|
node->slots[0] = (void __rcu *)RADIX_TREE_RETRY;
|
|
if (update_node)
|
|
update_node(node, private);
|
|
}
|
|
|
|
WARN_ON_ONCE(!list_empty(&node->private_list));
|
|
radix_tree_node_free(node);
|
|
shrunk = true;
|
|
}
|
|
|
|
return shrunk;
|
|
}
|
|
|
|
static bool delete_node(struct radix_tree_root *root,
|
|
struct radix_tree_node *node,
|
|
radix_tree_update_node_t update_node, void *private)
|
|
{
|
|
bool deleted = false;
|
|
|
|
do {
|
|
struct radix_tree_node *parent;
|
|
|
|
if (node->count) {
|
|
if (node_to_entry(node) ==
|
|
rcu_dereference_raw(root->rnode))
|
|
deleted |= radix_tree_shrink(root, update_node,
|
|
private);
|
|
return deleted;
|
|
}
|
|
|
|
parent = node->parent;
|
|
if (parent) {
|
|
parent->slots[node->offset] = NULL;
|
|
parent->count--;
|
|
} else {
|
|
/*
|
|
* Shouldn't the tags already have all been cleared
|
|
* by the caller?
|
|
*/
|
|
if (!is_idr(root))
|
|
root_tag_clear_all(root);
|
|
root->rnode = NULL;
|
|
}
|
|
|
|
WARN_ON_ONCE(!list_empty(&node->private_list));
|
|
radix_tree_node_free(node);
|
|
deleted = true;
|
|
|
|
node = parent;
|
|
} while (node);
|
|
|
|
return deleted;
|
|
}
|
|
|
|
/**
|
|
* __radix_tree_create - create a slot in a radix tree
|
|
* @root: radix tree root
|
|
* @index: index key
|
|
* @order: index occupies 2^order aligned slots
|
|
* @nodep: returns node
|
|
* @slotp: returns slot
|
|
*
|
|
* Create, if necessary, and return the node and slot for an item
|
|
* at position @index in the radix tree @root.
|
|
*
|
|
* Until there is more than one item in the tree, no nodes are
|
|
* allocated and @root->rnode is used as a direct slot instead of
|
|
* pointing to a node, in which case *@nodep will be NULL.
|
|
*
|
|
* Returns -ENOMEM, or 0 for success.
|
|
*/
|
|
int __radix_tree_create(struct radix_tree_root *root, unsigned long index,
|
|
unsigned order, struct radix_tree_node **nodep,
|
|
void __rcu ***slotp)
|
|
{
|
|
struct radix_tree_node *node = NULL, *child;
|
|
void __rcu **slot = (void __rcu **)&root->rnode;
|
|
unsigned long maxindex;
|
|
unsigned int shift, offset = 0;
|
|
unsigned long max = index | ((1UL << order) - 1);
|
|
gfp_t gfp = root_gfp_mask(root);
|
|
|
|
shift = radix_tree_load_root(root, &child, &maxindex);
|
|
|
|
/* Make sure the tree is high enough. */
|
|
if (order > 0 && max == ((1UL << order) - 1))
|
|
max++;
|
|
if (max > maxindex) {
|
|
int error = radix_tree_extend(root, gfp, max, shift);
|
|
if (error < 0)
|
|
return error;
|
|
shift = error;
|
|
child = rcu_dereference_raw(root->rnode);
|
|
}
|
|
|
|
while (shift > order) {
|
|
shift -= RADIX_TREE_MAP_SHIFT;
|
|
if (child == NULL) {
|
|
/* Have to add a child node. */
|
|
child = radix_tree_node_alloc(gfp, node, root, shift,
|
|
offset, 0, 0);
|
|
if (!child)
|
|
return -ENOMEM;
|
|
rcu_assign_pointer(*slot, node_to_entry(child));
|
|
if (node)
|
|
node->count++;
|
|
} else if (!radix_tree_is_internal_node(child))
|
|
break;
|
|
|
|
/* Go a level down */
|
|
node = entry_to_node(child);
|
|
offset = radix_tree_descend(node, &child, index);
|
|
slot = &node->slots[offset];
|
|
}
|
|
|
|
if (nodep)
|
|
*nodep = node;
|
|
if (slotp)
|
|
*slotp = slot;
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* Free any nodes below this node. The tree is presumed to not need
|
|
* shrinking, and any user data in the tree is presumed to not need a
|
|
* destructor called on it. If we need to add a destructor, we can
|
|
* add that functionality later. Note that we may not clear tags or
|
|
* slots from the tree as an RCU walker may still have a pointer into
|
|
* this subtree. We could replace the entries with RADIX_TREE_RETRY,
|
|
* but we'll still have to clear those in rcu_free.
|
|
*/
|
|
static void radix_tree_free_nodes(struct radix_tree_node *node)
|
|
{
|
|
unsigned offset = 0;
|
|
struct radix_tree_node *child = entry_to_node(node);
|
|
|
|
for (;;) {
|
|
void *entry = rcu_dereference_raw(child->slots[offset]);
|
|
if (radix_tree_is_internal_node(entry) &&
|
|
!is_sibling_entry(child, entry)) {
|
|
child = entry_to_node(entry);
|
|
offset = 0;
|
|
continue;
|
|
}
|
|
offset++;
|
|
while (offset == RADIX_TREE_MAP_SIZE) {
|
|
struct radix_tree_node *old = child;
|
|
offset = child->offset + 1;
|
|
child = child->parent;
|
|
WARN_ON_ONCE(!list_empty(&old->private_list));
|
|
radix_tree_node_free(old);
|
|
if (old == entry_to_node(node))
|
|
return;
|
|
}
|
|
}
|
|
}
|
|
|
|
#ifdef CONFIG_RADIX_TREE_MULTIORDER
|
|
static inline int insert_entries(struct radix_tree_node *node,
|
|
void __rcu **slot, void *item, unsigned order, bool replace)
|
|
{
|
|
struct radix_tree_node *child;
|
|
unsigned i, n, tag, offset, tags = 0;
|
|
|
|
if (node) {
|
|
if (order > node->shift)
|
|
n = 1 << (order - node->shift);
|
|
else
|
|
n = 1;
|
|
offset = get_slot_offset(node, slot);
|
|
} else {
|
|
n = 1;
|
|
offset = 0;
|
|
}
|
|
|
|
if (n > 1) {
|
|
offset = offset & ~(n - 1);
|
|
slot = &node->slots[offset];
|
|
}
|
|
child = node_to_entry(slot);
|
|
|
|
for (i = 0; i < n; i++) {
|
|
if (slot[i]) {
|
|
if (replace) {
|
|
node->count--;
|
|
for (tag = 0; tag < RADIX_TREE_MAX_TAGS; tag++)
|
|
if (tag_get(node, tag, offset + i))
|
|
tags |= 1 << tag;
|
|
} else
|
|
return -EEXIST;
|
|
}
|
|
}
|
|
|
|
for (i = 0; i < n; i++) {
|
|
struct radix_tree_node *old = rcu_dereference_raw(slot[i]);
|
|
if (i) {
|
|
rcu_assign_pointer(slot[i], child);
|
|
for (tag = 0; tag < RADIX_TREE_MAX_TAGS; tag++)
|
|
if (tags & (1 << tag))
|
|
tag_clear(node, tag, offset + i);
|
|
} else {
|
|
rcu_assign_pointer(slot[i], item);
|
|
for (tag = 0; tag < RADIX_TREE_MAX_TAGS; tag++)
|
|
if (tags & (1 << tag))
|
|
tag_set(node, tag, offset);
|
|
}
|
|
if (radix_tree_is_internal_node(old) &&
|
|
!is_sibling_entry(node, old) &&
|
|
(old != RADIX_TREE_RETRY))
|
|
radix_tree_free_nodes(old);
|
|
if (radix_tree_exceptional_entry(old))
|
|
node->exceptional--;
|
|
}
|
|
if (node) {
|
|
node->count += n;
|
|
if (radix_tree_exceptional_entry(item))
|
|
node->exceptional += n;
|
|
}
|
|
return n;
|
|
}
|
|
#else
|
|
static inline int insert_entries(struct radix_tree_node *node,
|
|
void __rcu **slot, void *item, unsigned order, bool replace)
|
|
{
|
|
if (*slot)
|
|
return -EEXIST;
|
|
rcu_assign_pointer(*slot, item);
|
|
if (node) {
|
|
node->count++;
|
|
if (radix_tree_exceptional_entry(item))
|
|
node->exceptional++;
|
|
}
|
|
return 1;
|
|
}
|
|
#endif
|
|
|
|
/**
|
|
* __radix_tree_insert - insert into a radix tree
|
|
* @root: radix tree root
|
|
* @index: index key
|
|
* @order: key covers the 2^order indices around index
|
|
* @item: item to insert
|
|
*
|
|
* Insert an item into the radix tree at position @index.
|
|
*/
|
|
int __radix_tree_insert(struct radix_tree_root *root, unsigned long index,
|
|
unsigned order, void *item)
|
|
{
|
|
struct radix_tree_node *node;
|
|
void __rcu **slot;
|
|
int error;
|
|
|
|
BUG_ON(radix_tree_is_internal_node(item));
|
|
|
|
error = __radix_tree_create(root, index, order, &node, &slot);
|
|
if (error)
|
|
return error;
|
|
|
|
error = insert_entries(node, slot, item, order, false);
|
|
if (error < 0)
|
|
return error;
|
|
|
|
if (node) {
|
|
unsigned offset = get_slot_offset(node, slot);
|
|
BUG_ON(tag_get(node, 0, offset));
|
|
BUG_ON(tag_get(node, 1, offset));
|
|
BUG_ON(tag_get(node, 2, offset));
|
|
} else {
|
|
BUG_ON(root_tags_get(root));
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
EXPORT_SYMBOL(__radix_tree_insert);
|
|
|
|
/**
|
|
* __radix_tree_lookup - lookup an item in a radix tree
|
|
* @root: radix tree root
|
|
* @index: index key
|
|
* @nodep: returns node
|
|
* @slotp: returns slot
|
|
*
|
|
* Lookup and return the item at position @index in the radix
|
|
* tree @root.
|
|
*
|
|
* Until there is more than one item in the tree, no nodes are
|
|
* allocated and @root->rnode is used as a direct slot instead of
|
|
* pointing to a node, in which case *@nodep will be NULL.
|
|
*/
|
|
void *__radix_tree_lookup(const struct radix_tree_root *root,
|
|
unsigned long index, struct radix_tree_node **nodep,
|
|
void __rcu ***slotp)
|
|
{
|
|
struct radix_tree_node *node, *parent;
|
|
unsigned long maxindex;
|
|
void __rcu **slot;
|
|
|
|
restart:
|
|
parent = NULL;
|
|
slot = (void __rcu **)&root->rnode;
|
|
radix_tree_load_root(root, &node, &maxindex);
|
|
if (index > maxindex)
|
|
return NULL;
|
|
|
|
while (radix_tree_is_internal_node(node)) {
|
|
unsigned offset;
|
|
|
|
if (node == RADIX_TREE_RETRY)
|
|
goto restart;
|
|
parent = entry_to_node(node);
|
|
offset = radix_tree_descend(parent, &node, index);
|
|
slot = parent->slots + offset;
|
|
}
|
|
|
|
if (nodep)
|
|
*nodep = parent;
|
|
if (slotp)
|
|
*slotp = slot;
|
|
return 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 __rcu **radix_tree_lookup_slot(const struct radix_tree_root *root,
|
|
unsigned long index)
|
|
{
|
|
void __rcu **slot;
|
|
|
|
if (!__radix_tree_lookup(root, index, NULL, &slot))
|
|
return NULL;
|
|
return slot;
|
|
}
|
|
EXPORT_SYMBOL(radix_tree_lookup_slot);
|
|
|
|
/**
|
|
* radix_tree_lookup - perform lookup operation on a radix tree
|
|
* @root: radix tree root
|
|
* @index: index key
|
|
*
|
|
* Lookup the item at the position @index in the radix tree @root.
|
|
*
|
|
* This function can be called under rcu_read_lock, however the caller
|
|
* must manage lifetimes of leaf nodes (eg. RCU may also be used to free
|
|
* them safely). No RCU barriers are required to access or modify the
|
|
* returned item, however.
|
|
*/
|
|
void *radix_tree_lookup(const struct radix_tree_root *root, unsigned long index)
|
|
{
|
|
return __radix_tree_lookup(root, index, NULL, NULL);
|
|
}
|
|
EXPORT_SYMBOL(radix_tree_lookup);
|
|
|
|
static inline void replace_sibling_entries(struct radix_tree_node *node,
|
|
void __rcu **slot, int count, int exceptional)
|
|
{
|
|
#ifdef CONFIG_RADIX_TREE_MULTIORDER
|
|
void *ptr = node_to_entry(slot);
|
|
unsigned offset = get_slot_offset(node, slot) + 1;
|
|
|
|
while (offset < RADIX_TREE_MAP_SIZE) {
|
|
if (rcu_dereference_raw(node->slots[offset]) != ptr)
|
|
break;
|
|
if (count < 0) {
|
|
node->slots[offset] = NULL;
|
|
node->count--;
|
|
}
|
|
node->exceptional += exceptional;
|
|
offset++;
|
|
}
|
|
#endif
|
|
}
|
|
|
|
static void replace_slot(void __rcu **slot, void *item,
|
|
struct radix_tree_node *node, int count, int exceptional)
|
|
{
|
|
if (WARN_ON_ONCE(radix_tree_is_internal_node(item)))
|
|
return;
|
|
|
|
if (node && (count || exceptional)) {
|
|
node->count += count;
|
|
node->exceptional += exceptional;
|
|
replace_sibling_entries(node, slot, count, exceptional);
|
|
}
|
|
|
|
rcu_assign_pointer(*slot, item);
|
|
}
|
|
|
|
static bool node_tag_get(const struct radix_tree_root *root,
|
|
const struct radix_tree_node *node,
|
|
unsigned int tag, unsigned int offset)
|
|
{
|
|
if (node)
|
|
return tag_get(node, tag, offset);
|
|
return root_tag_get(root, tag);
|
|
}
|
|
|
|
/*
|
|
* IDR users want to be able to store NULL in the tree, so if the slot isn't
|
|
* free, don't adjust the count, even if it's transitioning between NULL and
|
|
* non-NULL. For the IDA, we mark slots as being IDR_FREE while they still
|
|
* have empty bits, but it only stores NULL in slots when they're being
|
|
* deleted.
|
|
*/
|
|
static int calculate_count(struct radix_tree_root *root,
|
|
struct radix_tree_node *node, void __rcu **slot,
|
|
void *item, void *old)
|
|
{
|
|
if (is_idr(root)) {
|
|
unsigned offset = get_slot_offset(node, slot);
|
|
bool free = node_tag_get(root, node, IDR_FREE, offset);
|
|
if (!free)
|
|
return 0;
|
|
if (!old)
|
|
return 1;
|
|
}
|
|
return !!item - !!old;
|
|
}
|
|
|
|
/**
|
|
* __radix_tree_replace - replace item in a slot
|
|
* @root: radix tree root
|
|
* @node: pointer to tree node
|
|
* @slot: pointer to slot in @node
|
|
* @item: new item to store in the slot.
|
|
* @update_node: callback for changing leaf nodes
|
|
* @private: private data to pass to @update_node
|
|
*
|
|
* For use with __radix_tree_lookup(). Caller must hold tree write locked
|
|
* across slot lookup and replacement.
|
|
*/
|
|
void __radix_tree_replace(struct radix_tree_root *root,
|
|
struct radix_tree_node *node,
|
|
void __rcu **slot, void *item,
|
|
radix_tree_update_node_t update_node, void *private)
|
|
{
|
|
void *old = rcu_dereference_raw(*slot);
|
|
int exceptional = !!radix_tree_exceptional_entry(item) -
|
|
!!radix_tree_exceptional_entry(old);
|
|
int count = calculate_count(root, node, slot, item, old);
|
|
|
|
/*
|
|
* This function supports replacing exceptional entries and
|
|
* deleting entries, but that needs accounting against the
|
|
* node unless the slot is root->rnode.
|
|
*/
|
|
WARN_ON_ONCE(!node && (slot != (void __rcu **)&root->rnode) &&
|
|
(count || exceptional));
|
|
replace_slot(slot, item, node, count, exceptional);
|
|
|
|
if (!node)
|
|
return;
|
|
|
|
if (update_node)
|
|
update_node(node, private);
|
|
|
|
delete_node(root, node, update_node, private);
|
|
}
|
|
|
|
/**
|
|
* radix_tree_replace_slot - replace item in a slot
|
|
* @root: radix tree root
|
|
* @slot: pointer to slot
|
|
* @item: new item to store in the slot.
|
|
*
|
|
* For use with radix_tree_lookup_slot(), radix_tree_gang_lookup_slot(),
|
|
* radix_tree_gang_lookup_tag_slot(). Caller must hold tree write locked
|
|
* across slot lookup and replacement.
|
|
*
|
|
* NOTE: This cannot be used to switch between non-entries (empty slots),
|
|
* regular entries, and exceptional entries, as that requires accounting
|
|
* inside the radix tree node. When switching from one type of entry or
|
|
* deleting, use __radix_tree_lookup() and __radix_tree_replace() or
|
|
* radix_tree_iter_replace().
|
|
*/
|
|
void radix_tree_replace_slot(struct radix_tree_root *root,
|
|
void __rcu **slot, void *item)
|
|
{
|
|
__radix_tree_replace(root, NULL, slot, item, NULL, NULL);
|
|
}
|
|
EXPORT_SYMBOL(radix_tree_replace_slot);
|
|
|
|
/**
|
|
* radix_tree_iter_replace - replace item in a slot
|
|
* @root: radix tree root
|
|
* @slot: pointer to slot
|
|
* @item: new item to store in the slot.
|
|
*
|
|
* For use with radix_tree_split() and radix_tree_for_each_slot().
|
|
* Caller must hold tree write locked across split and replacement.
|
|
*/
|
|
void radix_tree_iter_replace(struct radix_tree_root *root,
|
|
const struct radix_tree_iter *iter,
|
|
void __rcu **slot, void *item)
|
|
{
|
|
__radix_tree_replace(root, iter->node, slot, item, NULL, NULL);
|
|
}
|
|
|
|
#ifdef CONFIG_RADIX_TREE_MULTIORDER
|
|
/**
|
|
* radix_tree_join - replace multiple entries with one multiorder entry
|
|
* @root: radix tree root
|
|
* @index: an index inside the new entry
|
|
* @order: order of the new entry
|
|
* @item: new entry
|
|
*
|
|
* Call this function to replace several entries with one larger entry.
|
|
* The existing entries are presumed to not need freeing as a result of
|
|
* this call.
|
|
*
|
|
* The replacement entry will have all the tags set on it that were set
|
|
* on any of the entries it is replacing.
|
|
*/
|
|
int radix_tree_join(struct radix_tree_root *root, unsigned long index,
|
|
unsigned order, void *item)
|
|
{
|
|
struct radix_tree_node *node;
|
|
void __rcu **slot;
|
|
int error;
|
|
|
|
BUG_ON(radix_tree_is_internal_node(item));
|
|
|
|
error = __radix_tree_create(root, index, order, &node, &slot);
|
|
if (!error)
|
|
error = insert_entries(node, slot, item, order, true);
|
|
if (error > 0)
|
|
error = 0;
|
|
|
|
return error;
|
|
}
|
|
|
|
/**
|
|
* radix_tree_split - Split an entry into smaller entries
|
|
* @root: radix tree root
|
|
* @index: An index within the large entry
|
|
* @order: Order of new entries
|
|
*
|
|
* Call this function as the first step in replacing a multiorder entry
|
|
* with several entries of lower order. After this function returns,
|
|
* loop over the relevant portion of the tree using radix_tree_for_each_slot()
|
|
* and call radix_tree_iter_replace() to set up each new entry.
|
|
*
|
|
* The tags from this entry are replicated to all the new entries.
|
|
*
|
|
* The radix tree should be locked against modification during the entire
|
|
* replacement operation. Lock-free lookups will see RADIX_TREE_RETRY which
|
|
* should prompt RCU walkers to restart the lookup from the root.
|
|
*/
|
|
int radix_tree_split(struct radix_tree_root *root, unsigned long index,
|
|
unsigned order)
|
|
{
|
|
struct radix_tree_node *parent, *node, *child;
|
|
void __rcu **slot;
|
|
unsigned int offset, end;
|
|
unsigned n, tag, tags = 0;
|
|
gfp_t gfp = root_gfp_mask(root);
|
|
|
|
if (!__radix_tree_lookup(root, index, &parent, &slot))
|
|
return -ENOENT;
|
|
if (!parent)
|
|
return -ENOENT;
|
|
|
|
offset = get_slot_offset(parent, slot);
|
|
|
|
for (tag = 0; tag < RADIX_TREE_MAX_TAGS; tag++)
|
|
if (tag_get(parent, tag, offset))
|
|
tags |= 1 << tag;
|
|
|
|
for (end = offset + 1; end < RADIX_TREE_MAP_SIZE; end++) {
|
|
if (!is_sibling_entry(parent,
|
|
rcu_dereference_raw(parent->slots[end])))
|
|
break;
|
|
for (tag = 0; tag < RADIX_TREE_MAX_TAGS; tag++)
|
|
if (tags & (1 << tag))
|
|
tag_set(parent, tag, end);
|
|
/* rcu_assign_pointer ensures tags are set before RETRY */
|
|
rcu_assign_pointer(parent->slots[end], RADIX_TREE_RETRY);
|
|
}
|
|
rcu_assign_pointer(parent->slots[offset], RADIX_TREE_RETRY);
|
|
parent->exceptional -= (end - offset);
|
|
|
|
if (order == parent->shift)
|
|
return 0;
|
|
if (order > parent->shift) {
|
|
while (offset < end)
|
|
offset += insert_entries(parent, &parent->slots[offset],
|
|
RADIX_TREE_RETRY, order, true);
|
|
return 0;
|
|
}
|
|
|
|
node = parent;
|
|
|
|
for (;;) {
|
|
if (node->shift > order) {
|
|
child = radix_tree_node_alloc(gfp, node, root,
|
|
node->shift - RADIX_TREE_MAP_SHIFT,
|
|
offset, 0, 0);
|
|
if (!child)
|
|
goto nomem;
|
|
if (node != parent) {
|
|
node->count++;
|
|
rcu_assign_pointer(node->slots[offset],
|
|
node_to_entry(child));
|
|
for (tag = 0; tag < RADIX_TREE_MAX_TAGS; tag++)
|
|
if (tags & (1 << tag))
|
|
tag_set(node, tag, offset);
|
|
}
|
|
|
|
node = child;
|
|
offset = 0;
|
|
continue;
|
|
}
|
|
|
|
n = insert_entries(node, &node->slots[offset],
|
|
RADIX_TREE_RETRY, order, false);
|
|
BUG_ON(n > RADIX_TREE_MAP_SIZE);
|
|
|
|
for (tag = 0; tag < RADIX_TREE_MAX_TAGS; tag++)
|
|
if (tags & (1 << tag))
|
|
tag_set(node, tag, offset);
|
|
offset += n;
|
|
|
|
while (offset == RADIX_TREE_MAP_SIZE) {
|
|
if (node == parent)
|
|
break;
|
|
offset = node->offset;
|
|
child = node;
|
|
node = node->parent;
|
|
rcu_assign_pointer(node->slots[offset],
|
|
node_to_entry(child));
|
|
offset++;
|
|
}
|
|
if ((node == parent) && (offset == end))
|
|
return 0;
|
|
}
|
|
|
|
nomem:
|
|
/* Shouldn't happen; did user forget to preload? */
|
|
/* TODO: free all the allocated nodes */
|
|
WARN_ON(1);
|
|
return -ENOMEM;
|
|
}
|
|
#endif
|
|
|
|
static void node_tag_set(struct radix_tree_root *root,
|
|
struct radix_tree_node *node,
|
|
unsigned int tag, unsigned int offset)
|
|
{
|
|
while (node) {
|
|
if (tag_get(node, tag, offset))
|
|
return;
|
|
tag_set(node, tag, offset);
|
|
offset = node->offset;
|
|
node = node->parent;
|
|
}
|
|
|
|
if (!root_tag_get(root, tag))
|
|
root_tag_set(root, tag);
|
|
}
|
|
|
|
/**
|
|
* radix_tree_tag_set - set a tag on a radix tree node
|
|
* @root: radix tree root
|
|
* @index: index key
|
|
* @tag: tag index
|
|
*
|
|
* Set the search tag (which must be < RADIX_TREE_MAX_TAGS)
|
|
* corresponding to @index in the radix tree. From
|
|
* the root all the way down to the leaf node.
|
|
*
|
|
* Returns the address of the tagged item. Setting a tag on a not-present
|
|
* item is a bug.
|
|
*/
|
|
void *radix_tree_tag_set(struct radix_tree_root *root,
|
|
unsigned long index, unsigned int tag)
|
|
{
|
|
struct radix_tree_node *node, *parent;
|
|
unsigned long maxindex;
|
|
|
|
radix_tree_load_root(root, &node, &maxindex);
|
|
BUG_ON(index > maxindex);
|
|
|
|
while (radix_tree_is_internal_node(node)) {
|
|
unsigned offset;
|
|
|
|
parent = entry_to_node(node);
|
|
offset = radix_tree_descend(parent, &node, index);
|
|
BUG_ON(!node);
|
|
|
|
if (!tag_get(parent, tag, offset))
|
|
tag_set(parent, tag, offset);
|
|
}
|
|
|
|
/* set the root's tag bit */
|
|
if (!root_tag_get(root, tag))
|
|
root_tag_set(root, tag);
|
|
|
|
return node;
|
|
}
|
|
EXPORT_SYMBOL(radix_tree_tag_set);
|
|
|
|
/**
|
|
* radix_tree_iter_tag_set - set a tag on the current iterator entry
|
|
* @root: radix tree root
|
|
* @iter: iterator state
|
|
* @tag: tag to set
|
|
*/
|
|
void radix_tree_iter_tag_set(struct radix_tree_root *root,
|
|
const struct radix_tree_iter *iter, unsigned int tag)
|
|
{
|
|
node_tag_set(root, iter->node, tag, iter_offset(iter));
|
|
}
|
|
|
|
static void node_tag_clear(struct radix_tree_root *root,
|
|
struct radix_tree_node *node,
|
|
unsigned int tag, unsigned int offset)
|
|
{
|
|
while (node) {
|
|
if (!tag_get(node, tag, offset))
|
|
return;
|
|
tag_clear(node, tag, offset);
|
|
if (any_tag_set(node, tag))
|
|
return;
|
|
|
|
offset = node->offset;
|
|
node = node->parent;
|
|
}
|
|
|
|
/* clear the root's tag bit */
|
|
if (root_tag_get(root, tag))
|
|
root_tag_clear(root, tag);
|
|
}
|
|
|
|
/**
|
|
* radix_tree_tag_clear - clear a tag on a radix tree node
|
|
* @root: radix tree root
|
|
* @index: index key
|
|
* @tag: tag index
|
|
*
|
|
* Clear the search tag (which must be < RADIX_TREE_MAX_TAGS)
|
|
* corresponding to @index in the radix tree. If this causes
|
|
* the leaf node to have no tags set then clear the tag in the
|
|
* next-to-leaf node, etc.
|
|
*
|
|
* Returns the address of the tagged item on success, else NULL. ie:
|
|
* has the same return value and semantics as radix_tree_lookup().
|
|
*/
|
|
void *radix_tree_tag_clear(struct radix_tree_root *root,
|
|
unsigned long index, unsigned int tag)
|
|
{
|
|
struct radix_tree_node *node, *parent;
|
|
unsigned long maxindex;
|
|
int uninitialized_var(offset);
|
|
|
|
radix_tree_load_root(root, &node, &maxindex);
|
|
if (index > maxindex)
|
|
return NULL;
|
|
|
|
parent = NULL;
|
|
|
|
while (radix_tree_is_internal_node(node)) {
|
|
parent = entry_to_node(node);
|
|
offset = radix_tree_descend(parent, &node, index);
|
|
}
|
|
|
|
if (node)
|
|
node_tag_clear(root, parent, tag, offset);
|
|
|
|
return node;
|
|
}
|
|
EXPORT_SYMBOL(radix_tree_tag_clear);
|
|
|
|
/**
|
|
* radix_tree_iter_tag_clear - clear a tag on the current iterator entry
|
|
* @root: radix tree root
|
|
* @iter: iterator state
|
|
* @tag: tag to clear
|
|
*/
|
|
void radix_tree_iter_tag_clear(struct radix_tree_root *root,
|
|
const struct radix_tree_iter *iter, unsigned int tag)
|
|
{
|
|
node_tag_clear(root, iter->node, tag, iter_offset(iter));
|
|
}
|
|
|
|
/**
|
|
* radix_tree_tag_get - get a tag on a radix tree node
|
|
* @root: radix tree root
|
|
* @index: index key
|
|
* @tag: tag index (< RADIX_TREE_MAX_TAGS)
|
|
*
|
|
* Return values:
|
|
*
|
|
* 0: tag not present or not set
|
|
* 1: tag set
|
|
*
|
|
* Note that the return value of this function may not be relied on, even if
|
|
* the RCU lock is held, unless tag modification and node deletion are excluded
|
|
* from concurrency.
|
|
*/
|
|
int radix_tree_tag_get(const struct radix_tree_root *root,
|
|
unsigned long index, unsigned int tag)
|
|
{
|
|
struct radix_tree_node *node, *parent;
|
|
unsigned long maxindex;
|
|
|
|
if (!root_tag_get(root, tag))
|
|
return 0;
|
|
|
|
radix_tree_load_root(root, &node, &maxindex);
|
|
if (index > maxindex)
|
|
return 0;
|
|
|
|
while (radix_tree_is_internal_node(node)) {
|
|
unsigned offset;
|
|
|
|
parent = entry_to_node(node);
|
|
offset = radix_tree_descend(parent, &node, index);
|
|
|
|
if (!tag_get(parent, tag, offset))
|
|
return 0;
|
|
if (node == RADIX_TREE_RETRY)
|
|
break;
|
|
}
|
|
|
|
return 1;
|
|
}
|
|
EXPORT_SYMBOL(radix_tree_tag_get);
|
|
|
|
static inline void __set_iter_shift(struct radix_tree_iter *iter,
|
|
unsigned int shift)
|
|
{
|
|
#ifdef CONFIG_RADIX_TREE_MULTIORDER
|
|
iter->shift = shift;
|
|
#endif
|
|
}
|
|
|
|
/* Construct iter->tags bit-mask from node->tags[tag] array */
|
|
static void set_iter_tags(struct radix_tree_iter *iter,
|
|
struct radix_tree_node *node, unsigned offset,
|
|
unsigned tag)
|
|
{
|
|
unsigned tag_long = offset / BITS_PER_LONG;
|
|
unsigned tag_bit = offset % BITS_PER_LONG;
|
|
|
|
if (!node) {
|
|
iter->tags = 1;
|
|
return;
|
|
}
|
|
|
|
iter->tags = node->tags[tag][tag_long] >> tag_bit;
|
|
|
|
/* This never happens if RADIX_TREE_TAG_LONGS == 1 */
|
|
if (tag_long < RADIX_TREE_TAG_LONGS - 1) {
|
|
/* Pick tags from next element */
|
|
if (tag_bit)
|
|
iter->tags |= node->tags[tag][tag_long + 1] <<
|
|
(BITS_PER_LONG - tag_bit);
|
|
/* Clip chunk size, here only BITS_PER_LONG tags */
|
|
iter->next_index = __radix_tree_iter_add(iter, BITS_PER_LONG);
|
|
}
|
|
}
|
|
|
|
#ifdef CONFIG_RADIX_TREE_MULTIORDER
|
|
static void __rcu **skip_siblings(struct radix_tree_node **nodep,
|
|
void __rcu **slot, struct radix_tree_iter *iter)
|
|
{
|
|
while (iter->index < iter->next_index) {
|
|
*nodep = rcu_dereference_raw(*slot);
|
|
if (*nodep && !is_sibling_entry(iter->node, *nodep))
|
|
return slot;
|
|
slot++;
|
|
iter->index = __radix_tree_iter_add(iter, 1);
|
|
iter->tags >>= 1;
|
|
}
|
|
|
|
*nodep = NULL;
|
|
return NULL;
|
|
}
|
|
|
|
void __rcu **__radix_tree_next_slot(void __rcu **slot,
|
|
struct radix_tree_iter *iter, unsigned flags)
|
|
{
|
|
unsigned tag = flags & RADIX_TREE_ITER_TAG_MASK;
|
|
struct radix_tree_node *node;
|
|
|
|
slot = skip_siblings(&node, slot, iter);
|
|
|
|
while (radix_tree_is_internal_node(node)) {
|
|
unsigned offset;
|
|
unsigned long next_index;
|
|
|
|
if (node == RADIX_TREE_RETRY)
|
|
return slot;
|
|
node = entry_to_node(node);
|
|
iter->node = node;
|
|
iter->shift = node->shift;
|
|
|
|
if (flags & RADIX_TREE_ITER_TAGGED) {
|
|
offset = radix_tree_find_next_bit(node, tag, 0);
|
|
if (offset == RADIX_TREE_MAP_SIZE)
|
|
return NULL;
|
|
slot = &node->slots[offset];
|
|
iter->index = __radix_tree_iter_add(iter, offset);
|
|
set_iter_tags(iter, node, offset, tag);
|
|
node = rcu_dereference_raw(*slot);
|
|
} else {
|
|
offset = 0;
|
|
slot = &node->slots[0];
|
|
for (;;) {
|
|
node = rcu_dereference_raw(*slot);
|
|
if (node)
|
|
break;
|
|
slot++;
|
|
offset++;
|
|
if (offset == RADIX_TREE_MAP_SIZE)
|
|
return NULL;
|
|
}
|
|
iter->index = __radix_tree_iter_add(iter, offset);
|
|
}
|
|
if ((flags & RADIX_TREE_ITER_CONTIG) && (offset > 0))
|
|
goto none;
|
|
next_index = (iter->index | shift_maxindex(iter->shift)) + 1;
|
|
if (next_index < iter->next_index)
|
|
iter->next_index = next_index;
|
|
}
|
|
|
|
return slot;
|
|
none:
|
|
iter->next_index = 0;
|
|
return NULL;
|
|
}
|
|
EXPORT_SYMBOL(__radix_tree_next_slot);
|
|
#else
|
|
static void __rcu **skip_siblings(struct radix_tree_node **nodep,
|
|
void __rcu **slot, struct radix_tree_iter *iter)
|
|
{
|
|
return slot;
|
|
}
|
|
#endif
|
|
|
|
void __rcu **radix_tree_iter_resume(void __rcu **slot,
|
|
struct radix_tree_iter *iter)
|
|
{
|
|
struct radix_tree_node *node;
|
|
|
|
slot++;
|
|
iter->index = __radix_tree_iter_add(iter, 1);
|
|
skip_siblings(&node, slot, iter);
|
|
iter->next_index = iter->index;
|
|
iter->tags = 0;
|
|
return NULL;
|
|
}
|
|
EXPORT_SYMBOL(radix_tree_iter_resume);
|
|
|
|
/**
|
|
* radix_tree_next_chunk - find next chunk of slots for iteration
|
|
*
|
|
* @root: radix tree root
|
|
* @iter: iterator state
|
|
* @flags: RADIX_TREE_ITER_* flags and tag index
|
|
* Returns: pointer to chunk first slot, or NULL if iteration is over
|
|
*/
|
|
void __rcu **radix_tree_next_chunk(const struct radix_tree_root *root,
|
|
struct radix_tree_iter *iter, unsigned flags)
|
|
{
|
|
unsigned tag = flags & RADIX_TREE_ITER_TAG_MASK;
|
|
struct radix_tree_node *node, *child;
|
|
unsigned long index, offset, maxindex;
|
|
|
|
if ((flags & RADIX_TREE_ITER_TAGGED) && !root_tag_get(root, tag))
|
|
return NULL;
|
|
|
|
/*
|
|
* Catch next_index overflow after ~0UL. iter->index never overflows
|
|
* during iterating; it can be zero only at the beginning.
|
|
* And we cannot overflow iter->next_index in a single step,
|
|
* because RADIX_TREE_MAP_SHIFT < BITS_PER_LONG.
|
|
*
|
|
* This condition also used by radix_tree_next_slot() to stop
|
|
* contiguous iterating, and forbid switching to the next chunk.
|
|
*/
|
|
index = iter->next_index;
|
|
if (!index && iter->index)
|
|
return NULL;
|
|
|
|
restart:
|
|
radix_tree_load_root(root, &child, &maxindex);
|
|
if (index > maxindex)
|
|
return NULL;
|
|
if (!child)
|
|
return NULL;
|
|
|
|
if (!radix_tree_is_internal_node(child)) {
|
|
/* Single-slot tree */
|
|
iter->index = index;
|
|
iter->next_index = maxindex + 1;
|
|
iter->tags = 1;
|
|
iter->node = NULL;
|
|
__set_iter_shift(iter, 0);
|
|
return (void __rcu **)&root->rnode;
|
|
}
|
|
|
|
do {
|
|
node = entry_to_node(child);
|
|
offset = radix_tree_descend(node, &child, index);
|
|
|
|
if ((flags & RADIX_TREE_ITER_TAGGED) ?
|
|
!tag_get(node, tag, offset) : !child) {
|
|
/* Hole detected */
|
|
if (flags & RADIX_TREE_ITER_CONTIG)
|
|
return NULL;
|
|
|
|
if (flags & RADIX_TREE_ITER_TAGGED)
|
|
offset = radix_tree_find_next_bit(node, tag,
|
|
offset + 1);
|
|
else
|
|
while (++offset < RADIX_TREE_MAP_SIZE) {
|
|
void *slot = rcu_dereference_raw(
|
|
node->slots[offset]);
|
|
if (is_sibling_entry(node, slot))
|
|
continue;
|
|
if (slot)
|
|
break;
|
|
}
|
|
index &= ~node_maxindex(node);
|
|
index += offset << node->shift;
|
|
/* Overflow after ~0UL */
|
|
if (!index)
|
|
return NULL;
|
|
if (offset == RADIX_TREE_MAP_SIZE)
|
|
goto restart;
|
|
child = rcu_dereference_raw(node->slots[offset]);
|
|
}
|
|
|
|
if (!child)
|
|
goto restart;
|
|
if (child == RADIX_TREE_RETRY)
|
|
break;
|
|
} while (radix_tree_is_internal_node(child));
|
|
|
|
/* Update the iterator state */
|
|
iter->index = (index &~ node_maxindex(node)) | (offset << node->shift);
|
|
iter->next_index = (index | node_maxindex(node)) + 1;
|
|
iter->node = node;
|
|
__set_iter_shift(iter, node->shift);
|
|
|
|
if (flags & RADIX_TREE_ITER_TAGGED)
|
|
set_iter_tags(iter, node, offset, tag);
|
|
|
|
return node->slots + offset;
|
|
}
|
|
EXPORT_SYMBOL(radix_tree_next_chunk);
|
|
|
|
/**
|
|
* radix_tree_gang_lookup - perform multiple lookup on a radix tree
|
|
* @root: radix tree root
|
|
* @results: where the results of the lookup are placed
|
|
* @first_index: start the lookup from this key
|
|
* @max_items: place up to this many items at *results
|
|
*
|
|
* Performs an index-ascending scan of the tree for present items. Places
|
|
* them at *@results and returns the number of items which were placed at
|
|
* *@results.
|
|
*
|
|
* The implementation is naive.
|
|
*
|
|
* Like radix_tree_lookup, radix_tree_gang_lookup may be called under
|
|
* rcu_read_lock. In this case, rather than the returned results being
|
|
* an atomic snapshot of the tree at a single point in time, the
|
|
* semantics of an RCU protected gang lookup are as though multiple
|
|
* radix_tree_lookups have been issued in individual locks, and results
|
|
* stored in 'results'.
|
|
*/
|
|
unsigned int
|
|
radix_tree_gang_lookup(const struct radix_tree_root *root, void **results,
|
|
unsigned long first_index, unsigned int max_items)
|
|
{
|
|
struct radix_tree_iter iter;
|
|
void __rcu **slot;
|
|
unsigned int ret = 0;
|
|
|
|
if (unlikely(!max_items))
|
|
return 0;
|
|
|
|
radix_tree_for_each_slot(slot, root, &iter, first_index) {
|
|
results[ret] = rcu_dereference_raw(*slot);
|
|
if (!results[ret])
|
|
continue;
|
|
if (radix_tree_is_internal_node(results[ret])) {
|
|
slot = radix_tree_iter_retry(&iter);
|
|
continue;
|
|
}
|
|
if (++ret == max_items)
|
|
break;
|
|
}
|
|
|
|
return ret;
|
|
}
|
|
EXPORT_SYMBOL(radix_tree_gang_lookup);
|
|
|
|
/**
|
|
* radix_tree_gang_lookup_slot - perform multiple slot lookup on radix tree
|
|
* @root: radix tree root
|
|
* @results: where the results of the lookup are placed
|
|
* @indices: where their indices should be placed (but usually NULL)
|
|
* @first_index: start the lookup from this key
|
|
* @max_items: place up to this many items at *results
|
|
*
|
|
* Performs an index-ascending scan of the tree for present items. Places
|
|
* their slots at *@results and returns the number of items which were
|
|
* placed at *@results.
|
|
*
|
|
* The implementation is naive.
|
|
*
|
|
* Like radix_tree_gang_lookup as far as RCU and locking goes. Slots must
|
|
* be dereferenced with radix_tree_deref_slot, and if using only RCU
|
|
* protection, radix_tree_deref_slot may fail requiring a retry.
|
|
*/
|
|
unsigned int
|
|
radix_tree_gang_lookup_slot(const struct radix_tree_root *root,
|
|
void __rcu ***results, unsigned long *indices,
|
|
unsigned long first_index, unsigned int max_items)
|
|
{
|
|
struct radix_tree_iter iter;
|
|
void __rcu **slot;
|
|
unsigned int ret = 0;
|
|
|
|
if (unlikely(!max_items))
|
|
return 0;
|
|
|
|
radix_tree_for_each_slot(slot, root, &iter, first_index) {
|
|
results[ret] = slot;
|
|
if (indices)
|
|
indices[ret] = iter.index;
|
|
if (++ret == max_items)
|
|
break;
|
|
}
|
|
|
|
return ret;
|
|
}
|
|
EXPORT_SYMBOL(radix_tree_gang_lookup_slot);
|
|
|
|
/**
|
|
* radix_tree_gang_lookup_tag - perform multiple lookup on a radix tree
|
|
* based on a tag
|
|
* @root: radix tree root
|
|
* @results: where the results of the lookup are placed
|
|
* @first_index: start the lookup from this key
|
|
* @max_items: place up to this many items at *results
|
|
* @tag: the tag index (< RADIX_TREE_MAX_TAGS)
|
|
*
|
|
* Performs an index-ascending scan of the tree for present items which
|
|
* have the tag indexed by @tag set. Places the items at *@results and
|
|
* returns the number of items which were placed at *@results.
|
|
*/
|
|
unsigned int
|
|
radix_tree_gang_lookup_tag(const struct radix_tree_root *root, void **results,
|
|
unsigned long first_index, unsigned int max_items,
|
|
unsigned int tag)
|
|
{
|
|
struct radix_tree_iter iter;
|
|
void __rcu **slot;
|
|
unsigned int ret = 0;
|
|
|
|
if (unlikely(!max_items))
|
|
return 0;
|
|
|
|
radix_tree_for_each_tagged(slot, root, &iter, first_index, tag) {
|
|
results[ret] = rcu_dereference_raw(*slot);
|
|
if (!results[ret])
|
|
continue;
|
|
if (radix_tree_is_internal_node(results[ret])) {
|
|
slot = radix_tree_iter_retry(&iter);
|
|
continue;
|
|
}
|
|
if (++ret == max_items)
|
|
break;
|
|
}
|
|
|
|
return ret;
|
|
}
|
|
EXPORT_SYMBOL(radix_tree_gang_lookup_tag);
|
|
|
|
/**
|
|
* radix_tree_gang_lookup_tag_slot - perform multiple slot lookup on a
|
|
* radix tree based on a tag
|
|
* @root: radix tree root
|
|
* @results: where the results of the lookup are placed
|
|
* @first_index: start the lookup from this key
|
|
* @max_items: place up to this many items at *results
|
|
* @tag: the tag index (< RADIX_TREE_MAX_TAGS)
|
|
*
|
|
* Performs an index-ascending scan of the tree for present items which
|
|
* have the tag indexed by @tag set. Places the slots at *@results and
|
|
* returns the number of slots which were placed at *@results.
|
|
*/
|
|
unsigned int
|
|
radix_tree_gang_lookup_tag_slot(const struct radix_tree_root *root,
|
|
void __rcu ***results, unsigned long first_index,
|
|
unsigned int max_items, unsigned int tag)
|
|
{
|
|
struct radix_tree_iter iter;
|
|
void __rcu **slot;
|
|
unsigned int ret = 0;
|
|
|
|
if (unlikely(!max_items))
|
|
return 0;
|
|
|
|
radix_tree_for_each_tagged(slot, root, &iter, first_index, tag) {
|
|
results[ret] = slot;
|
|
if (++ret == max_items)
|
|
break;
|
|
}
|
|
|
|
return ret;
|
|
}
|
|
EXPORT_SYMBOL(radix_tree_gang_lookup_tag_slot);
|
|
|
|
/**
|
|
* __radix_tree_delete_node - try to free node after clearing a slot
|
|
* @root: radix tree root
|
|
* @node: node containing @index
|
|
* @update_node: callback for changing leaf nodes
|
|
* @private: private data to pass to @update_node
|
|
*
|
|
* After clearing the slot at @index in @node from radix tree
|
|
* rooted at @root, call this function to attempt freeing the
|
|
* node and shrinking the tree.
|
|
*/
|
|
void __radix_tree_delete_node(struct radix_tree_root *root,
|
|
struct radix_tree_node *node,
|
|
radix_tree_update_node_t update_node,
|
|
void *private)
|
|
{
|
|
delete_node(root, node, update_node, private);
|
|
}
|
|
|
|
static bool __radix_tree_delete(struct radix_tree_root *root,
|
|
struct radix_tree_node *node, void __rcu **slot)
|
|
{
|
|
void *old = rcu_dereference_raw(*slot);
|
|
int exceptional = radix_tree_exceptional_entry(old) ? -1 : 0;
|
|
unsigned offset = get_slot_offset(node, slot);
|
|
int tag;
|
|
|
|
if (is_idr(root))
|
|
node_tag_set(root, node, IDR_FREE, offset);
|
|
else
|
|
for (tag = 0; tag < RADIX_TREE_MAX_TAGS; tag++)
|
|
node_tag_clear(root, node, tag, offset);
|
|
|
|
replace_slot(slot, NULL, node, -1, exceptional);
|
|
return node && delete_node(root, node, NULL, NULL);
|
|
}
|
|
|
|
/**
|
|
* radix_tree_iter_delete - delete the entry at this iterator position
|
|
* @root: radix tree root
|
|
* @iter: iterator state
|
|
* @slot: pointer to slot
|
|
*
|
|
* Delete the entry at the position currently pointed to by the iterator.
|
|
* This may result in the current node being freed; if it is, the iterator
|
|
* is advanced so that it will not reference the freed memory. This
|
|
* function may be called without any locking if there are no other threads
|
|
* which can access this tree.
|
|
*/
|
|
void radix_tree_iter_delete(struct radix_tree_root *root,
|
|
struct radix_tree_iter *iter, void __rcu **slot)
|
|
{
|
|
if (__radix_tree_delete(root, iter->node, slot))
|
|
iter->index = iter->next_index;
|
|
}
|
|
EXPORT_SYMBOL(radix_tree_iter_delete);
|
|
|
|
/**
|
|
* radix_tree_delete_item - delete an item from a radix tree
|
|
* @root: radix tree root
|
|
* @index: index key
|
|
* @item: expected item
|
|
*
|
|
* Remove @item at @index from the radix tree rooted at @root.
|
|
*
|
|
* Return: the deleted entry, or %NULL if it was not present
|
|
* or the entry at the given @index was not @item.
|
|
*/
|
|
void *radix_tree_delete_item(struct radix_tree_root *root,
|
|
unsigned long index, void *item)
|
|
{
|
|
struct radix_tree_node *node = NULL;
|
|
void __rcu **slot = NULL;
|
|
void *entry;
|
|
|
|
entry = __radix_tree_lookup(root, index, &node, &slot);
|
|
if (!slot)
|
|
return NULL;
|
|
if (!entry && (!is_idr(root) || node_tag_get(root, node, IDR_FREE,
|
|
get_slot_offset(node, slot))))
|
|
return NULL;
|
|
|
|
if (item && entry != item)
|
|
return NULL;
|
|
|
|
__radix_tree_delete(root, node, slot);
|
|
|
|
return entry;
|
|
}
|
|
EXPORT_SYMBOL(radix_tree_delete_item);
|
|
|
|
/**
|
|
* radix_tree_delete - delete an entry from a radix tree
|
|
* @root: radix tree root
|
|
* @index: index key
|
|
*
|
|
* Remove the entry at @index from the radix tree rooted at @root.
|
|
*
|
|
* Return: The deleted entry, or %NULL if it was not present.
|
|
*/
|
|
void *radix_tree_delete(struct radix_tree_root *root, unsigned long index)
|
|
{
|
|
return radix_tree_delete_item(root, index, NULL);
|
|
}
|
|
EXPORT_SYMBOL(radix_tree_delete);
|
|
|
|
void radix_tree_clear_tags(struct radix_tree_root *root,
|
|
struct radix_tree_node *node,
|
|
void __rcu **slot)
|
|
{
|
|
if (node) {
|
|
unsigned int tag, offset = get_slot_offset(node, slot);
|
|
for (tag = 0; tag < RADIX_TREE_MAX_TAGS; tag++)
|
|
node_tag_clear(root, node, tag, offset);
|
|
} else {
|
|
root_tag_clear_all(root);
|
|
}
|
|
}
|
|
|
|
/**
|
|
* radix_tree_tagged - test whether any items in the tree are tagged
|
|
* @root: radix tree root
|
|
* @tag: tag to test
|
|
*/
|
|
int radix_tree_tagged(const struct radix_tree_root *root, unsigned int tag)
|
|
{
|
|
return root_tag_get(root, tag);
|
|
}
|
|
EXPORT_SYMBOL(radix_tree_tagged);
|
|
|
|
/**
|
|
* idr_preload - preload for idr_alloc()
|
|
* @gfp_mask: allocation mask to use for preloading
|
|
*
|
|
* Preallocate memory to use for the next call to idr_alloc(). This function
|
|
* returns with preemption disabled. It will be enabled by idr_preload_end().
|
|
*/
|
|
void idr_preload(gfp_t gfp_mask)
|
|
{
|
|
if (__radix_tree_preload(gfp_mask, IDR_PRELOAD_SIZE))
|
|
preempt_disable();
|
|
}
|
|
EXPORT_SYMBOL(idr_preload);
|
|
|
|
/**
|
|
* ida_pre_get - reserve resources for ida allocation
|
|
* @ida: ida handle
|
|
* @gfp: memory allocation flags
|
|
*
|
|
* This function should be called before calling ida_get_new_above(). If it
|
|
* is unable to allocate memory, it will return %0. On success, it returns %1.
|
|
*/
|
|
int ida_pre_get(struct ida *ida, gfp_t gfp)
|
|
{
|
|
/*
|
|
* The IDA API has no preload_end() equivalent. Instead,
|
|
* ida_get_new() can return -EAGAIN, prompting the caller
|
|
* to return to the ida_pre_get() step.
|
|
*/
|
|
if (!__radix_tree_preload(gfp, IDA_PRELOAD_SIZE))
|
|
preempt_enable();
|
|
|
|
if (!this_cpu_read(ida_bitmap)) {
|
|
struct ida_bitmap *bitmap = kmalloc(sizeof(*bitmap), gfp);
|
|
if (!bitmap)
|
|
return 0;
|
|
if (this_cpu_cmpxchg(ida_bitmap, NULL, bitmap))
|
|
kfree(bitmap);
|
|
}
|
|
|
|
return 1;
|
|
}
|
|
EXPORT_SYMBOL(ida_pre_get);
|
|
|
|
void __rcu **idr_get_free_cmn(struct radix_tree_root *root,
|
|
struct radix_tree_iter *iter, gfp_t gfp,
|
|
unsigned long max)
|
|
{
|
|
struct radix_tree_node *node = NULL, *child;
|
|
void __rcu **slot = (void __rcu **)&root->rnode;
|
|
unsigned long maxindex, start = iter->next_index;
|
|
unsigned int shift, offset = 0;
|
|
|
|
grow:
|
|
shift = radix_tree_load_root(root, &child, &maxindex);
|
|
if (!radix_tree_tagged(root, IDR_FREE))
|
|
start = max(start, maxindex + 1);
|
|
if (start > max)
|
|
return ERR_PTR(-ENOSPC);
|
|
|
|
if (start > maxindex) {
|
|
int error = radix_tree_extend(root, gfp, start, shift);
|
|
if (error < 0)
|
|
return ERR_PTR(error);
|
|
shift = error;
|
|
child = rcu_dereference_raw(root->rnode);
|
|
}
|
|
|
|
while (shift) {
|
|
shift -= RADIX_TREE_MAP_SHIFT;
|
|
if (child == NULL) {
|
|
/* Have to add a child node. */
|
|
child = radix_tree_node_alloc(gfp, node, root, shift,
|
|
offset, 0, 0);
|
|
if (!child)
|
|
return ERR_PTR(-ENOMEM);
|
|
all_tag_set(child, IDR_FREE);
|
|
rcu_assign_pointer(*slot, node_to_entry(child));
|
|
if (node)
|
|
node->count++;
|
|
} else if (!radix_tree_is_internal_node(child))
|
|
break;
|
|
|
|
node = entry_to_node(child);
|
|
offset = radix_tree_descend(node, &child, start);
|
|
if (!tag_get(node, IDR_FREE, offset)) {
|
|
offset = radix_tree_find_next_bit(node, IDR_FREE,
|
|
offset + 1);
|
|
start = next_index(start, node, offset);
|
|
if (start > max || start == 0)
|
|
return ERR_PTR(-ENOSPC);
|
|
while (offset == RADIX_TREE_MAP_SIZE) {
|
|
offset = node->offset + 1;
|
|
node = node->parent;
|
|
if (!node)
|
|
goto grow;
|
|
shift = node->shift;
|
|
}
|
|
child = rcu_dereference_raw(node->slots[offset]);
|
|
}
|
|
slot = &node->slots[offset];
|
|
}
|
|
|
|
iter->index = start;
|
|
if (node)
|
|
iter->next_index = 1 + min(max, (start | node_maxindex(node)));
|
|
else
|
|
iter->next_index = 1;
|
|
iter->node = node;
|
|
__set_iter_shift(iter, shift);
|
|
set_iter_tags(iter, node, offset, IDR_FREE);
|
|
|
|
return slot;
|
|
}
|
|
|
|
/**
|
|
* idr_destroy - release all internal memory from an IDR
|
|
* @idr: idr handle
|
|
*
|
|
* After this function is called, the IDR is empty, and may be reused or
|
|
* the data structure containing it may be freed.
|
|
*
|
|
* A typical clean-up sequence for objects stored in an idr tree will use
|
|
* idr_for_each() to free all objects, if necessary, then idr_destroy() to
|
|
* free the memory used to keep track of those objects.
|
|
*/
|
|
void idr_destroy(struct idr *idr)
|
|
{
|
|
struct radix_tree_node *node = rcu_dereference_raw(idr->idr_rt.rnode);
|
|
if (radix_tree_is_internal_node(node))
|
|
radix_tree_free_nodes(node);
|
|
idr->idr_rt.rnode = NULL;
|
|
root_tag_set(&idr->idr_rt, IDR_FREE);
|
|
}
|
|
EXPORT_SYMBOL(idr_destroy);
|
|
|
|
static void
|
|
radix_tree_node_ctor(void *arg)
|
|
{
|
|
struct radix_tree_node *node = arg;
|
|
|
|
memset(node, 0, sizeof(*node));
|
|
INIT_LIST_HEAD(&node->private_list);
|
|
}
|
|
|
|
static __init unsigned long __maxindex(unsigned int height)
|
|
{
|
|
unsigned int width = height * RADIX_TREE_MAP_SHIFT;
|
|
int shift = RADIX_TREE_INDEX_BITS - width;
|
|
|
|
if (shift < 0)
|
|
return ~0UL;
|
|
if (shift >= BITS_PER_LONG)
|
|
return 0UL;
|
|
return ~0UL >> shift;
|
|
}
|
|
|
|
static __init void radix_tree_init_maxnodes(void)
|
|
{
|
|
unsigned long height_to_maxindex[RADIX_TREE_MAX_PATH + 1];
|
|
unsigned int i, j;
|
|
|
|
for (i = 0; i < ARRAY_SIZE(height_to_maxindex); i++)
|
|
height_to_maxindex[i] = __maxindex(i);
|
|
for (i = 0; i < ARRAY_SIZE(height_to_maxnodes); i++) {
|
|
for (j = i; j > 0; j--)
|
|
height_to_maxnodes[i] += height_to_maxindex[j - 1] + 1;
|
|
}
|
|
}
|
|
|
|
static int radix_tree_cpu_dead(unsigned int cpu)
|
|
{
|
|
struct radix_tree_preload *rtp;
|
|
struct radix_tree_node *node;
|
|
|
|
/* Free per-cpu pool of preloaded nodes */
|
|
rtp = &per_cpu(radix_tree_preloads, cpu);
|
|
while (rtp->nr) {
|
|
node = rtp->nodes;
|
|
rtp->nodes = node->parent;
|
|
kmem_cache_free(radix_tree_node_cachep, node);
|
|
rtp->nr--;
|
|
}
|
|
kfree(per_cpu(ida_bitmap, cpu));
|
|
per_cpu(ida_bitmap, cpu) = NULL;
|
|
return 0;
|
|
}
|
|
|
|
void __init radix_tree_init(void)
|
|
{
|
|
int ret;
|
|
|
|
BUILD_BUG_ON(RADIX_TREE_MAX_TAGS + __GFP_BITS_SHIFT > 32);
|
|
radix_tree_node_cachep = kmem_cache_create("radix_tree_node",
|
|
sizeof(struct radix_tree_node), 0,
|
|
SLAB_PANIC | SLAB_RECLAIM_ACCOUNT,
|
|
radix_tree_node_ctor);
|
|
radix_tree_init_maxnodes();
|
|
ret = cpuhp_setup_state_nocalls(CPUHP_RADIX_DEAD, "lib/radix:dead",
|
|
NULL, radix_tree_cpu_dead);
|
|
WARN_ON(ret < 0);
|
|
}
|