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1607 lines
43 KiB
1607 lines
43 KiB
// SPDX-License-Identifier: GPL-2.0-or-later |
|
/* |
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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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|
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#include <linux/bitmap.h> |
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#include <linux/bitops.h> |
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#include <linux/bug.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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#include <linux/xarray.h> |
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|
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/* |
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* Radix tree node cache. |
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*/ |
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struct kmem_cache *radix_tree_node_cachep; |
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|
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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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/* |
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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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/* |
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* Per-cpu pool of preloaded nodes |
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*/ |
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DEFINE_PER_CPU(struct radix_tree_preload, radix_tree_preloads) = { |
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.lock = INIT_LOCAL_LOCK(lock), |
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}; |
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EXPORT_PER_CPU_SYMBOL_GPL(radix_tree_preloads); |
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|
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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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|
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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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|
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#define RADIX_TREE_RETRY XA_RETRY_ENTRY |
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|
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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 parent ? slot - parent->slots : 0; |
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} |
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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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|
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*nodep = (void *)entry; |
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return offset; |
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} |
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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->xa_flags & (__GFP_BITS_MASK & ~GFP_ZONEMASK); |
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} |
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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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|
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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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|
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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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|
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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->xa_flags |= (__force gfp_t)(1 << (tag + ROOT_TAG_SHIFT)); |
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} |
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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->xa_flags &= (__force gfp_t)~(1 << (tag + ROOT_TAG_SHIFT)); |
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} |
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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->xa_flags &= (__force gfp_t)((1 << ROOT_TAG_SHIFT) - 1); |
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} |
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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->xa_flags & (1 << (tag + ROOT_TAG_SHIFT)); |
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} |
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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->xa_flags >> ROOT_TAG_SHIFT; |
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} |
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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->xa_flags & ROOT_IS_IDR); |
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} |
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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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/** |
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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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* @node: where to begin the search |
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* @tag: the tag index |
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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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|
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if (offset < RADIX_TREE_MAP_SIZE) { |
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unsigned long tmp; |
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|
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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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|
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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 & RADIX_TREE_MAP_MASK; |
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} |
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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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|
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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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|
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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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|
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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 nr_values) |
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{ |
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struct radix_tree_node *ret = NULL; |
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|
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/* |
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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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|
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/* |
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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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*/ |
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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; |
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|
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/* |
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* 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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} |
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/* |
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* Update the allocation stack trace as this is more useful |
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* for debugging. |
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*/ |
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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); |
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out: |
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BUG_ON(radix_tree_is_internal_node(ret)); |
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if (ret) { |
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ret->shift = shift; |
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ret->offset = offset; |
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ret->count = count; |
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ret->nr_values = nr_values; |
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ret->parent = parent; |
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ret->array = root; |
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} |
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return ret; |
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} |
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|
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void radix_tree_node_rcu_free(struct rcu_head *head) |
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{ |
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struct radix_tree_node *node = |
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container_of(head, struct radix_tree_node, rcu_head); |
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|
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/* |
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* Must only free zeroed nodes into the slab. We can be left with |
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* non-NULL entries by radix_tree_free_nodes, so clear the entries |
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* and tags here. |
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*/ |
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memset(node->slots, 0, sizeof(node->slots)); |
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memset(node->tags, 0, sizeof(node->tags)); |
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INIT_LIST_HEAD(&node->private_list); |
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|
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kmem_cache_free(radix_tree_node_cachep, node); |
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} |
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|
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static inline void |
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radix_tree_node_free(struct radix_tree_node *node) |
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{ |
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call_rcu(&node->rcu_head, radix_tree_node_rcu_free); |
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} |
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|
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/* |
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* Load up this CPU's radix_tree_node buffer with sufficient objects to |
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* ensure that the addition of a single element in the tree cannot fail. On |
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* success, return zero, with preemption disabled. On error, return -ENOMEM |
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* with preemption not disabled. |
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* |
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* To make use of this facility, the radix tree must be initialised without |
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* __GFP_DIRECT_RECLAIM being passed to INIT_RADIX_TREE(). |
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*/ |
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static __must_check int __radix_tree_preload(gfp_t gfp_mask, unsigned nr) |
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{ |
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struct radix_tree_preload *rtp; |
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struct radix_tree_node *node; |
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int ret = -ENOMEM; |
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|
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/* |
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* Nodes preloaded by one cgroup can be used by another cgroup, so |
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* they should never be accounted to any particular memory cgroup. |
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*/ |
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gfp_mask &= ~__GFP_ACCOUNT; |
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|
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local_lock(&radix_tree_preloads.lock); |
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rtp = this_cpu_ptr(&radix_tree_preloads); |
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while (rtp->nr < nr) { |
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local_unlock(&radix_tree_preloads.lock); |
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node = kmem_cache_alloc(radix_tree_node_cachep, gfp_mask); |
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if (node == NULL) |
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goto out; |
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local_lock(&radix_tree_preloads.lock); |
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rtp = this_cpu_ptr(&radix_tree_preloads); |
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if (rtp->nr < nr) { |
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node->parent = rtp->nodes; |
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rtp->nodes = node; |
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rtp->nr++; |
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} else { |
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kmem_cache_free(radix_tree_node_cachep, node); |
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} |
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} |
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ret = 0; |
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out: |
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return ret; |
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} |
|
|
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/* |
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* Load up this CPU's radix_tree_node buffer with sufficient objects to |
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* ensure that the addition of a single element in the tree cannot fail. On |
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* success, return zero, with preemption disabled. On error, return -ENOMEM |
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* with preemption not disabled. |
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* |
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* To make use of this facility, the radix tree must be initialised without |
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* __GFP_DIRECT_RECLAIM being passed to INIT_RADIX_TREE(). |
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*/ |
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int radix_tree_preload(gfp_t gfp_mask) |
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{ |
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/* Warn on non-sensical use... */ |
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WARN_ON_ONCE(!gfpflags_allow_blocking(gfp_mask)); |
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return __radix_tree_preload(gfp_mask, RADIX_TREE_PRELOAD_SIZE); |
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} |
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EXPORT_SYMBOL(radix_tree_preload); |
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|
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/* |
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* The same as above function, except we don't guarantee preloading happens. |
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* We do it, if we decide it helps. On success, return zero with preemption |
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* disabled. On error, return -ENOMEM with preemption not disabled. |
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*/ |
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int radix_tree_maybe_preload(gfp_t gfp_mask) |
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{ |
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if (gfpflags_allow_blocking(gfp_mask)) |
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return __radix_tree_preload(gfp_mask, RADIX_TREE_PRELOAD_SIZE); |
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/* Preloading doesn't help anything with this gfp mask, skip it */ |
|
local_lock(&radix_tree_preloads.lock); |
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return 0; |
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} |
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EXPORT_SYMBOL(radix_tree_maybe_preload); |
|
|
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static unsigned radix_tree_load_root(const struct radix_tree_root *root, |
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struct radix_tree_node **nodep, unsigned long *maxindex) |
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{ |
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struct radix_tree_node *node = rcu_dereference_raw(root->xa_head); |
|
|
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*nodep = node; |
|
|
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if (likely(radix_tree_is_internal_node(node))) { |
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node = entry_to_node(node); |
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*maxindex = node_maxindex(node); |
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return node->shift + RADIX_TREE_MAP_SHIFT; |
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} |
|
|
|
*maxindex = 0; |
|
return 0; |
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} |
|
|
|
/* |
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* Extend a radix tree so it can store key @index. |
|
*/ |
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static int radix_tree_extend(struct radix_tree_root *root, gfp_t gfp, |
|
unsigned long index, unsigned int shift) |
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{ |
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void *entry; |
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unsigned int maxshift; |
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int tag; |
|
|
|
/* Figure out what the shift should be. */ |
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maxshift = shift; |
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while (index > shift_maxindex(maxshift)) |
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maxshift += RADIX_TREE_MAP_SHIFT; |
|
|
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entry = rcu_dereference_raw(root->xa_head); |
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if (!entry && (!is_idr(root) || root_tag_get(root, IDR_FREE))) |
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goto out; |
|
|
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do { |
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struct radix_tree_node *node = radix_tree_node_alloc(gfp, NULL, |
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root, shift, 0, 1, 0); |
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if (!node) |
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return -ENOMEM; |
|
|
|
if (is_idr(root)) { |
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all_tag_set(node, IDR_FREE); |
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if (!root_tag_get(root, IDR_FREE)) { |
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tag_clear(node, IDR_FREE, 0); |
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root_tag_set(root, IDR_FREE); |
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} |
|
} else { |
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/* Propagate the aggregated tag info to the new child */ |
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for (tag = 0; tag < RADIX_TREE_MAX_TAGS; tag++) { |
|
if (root_tag_get(root, tag)) |
|
tag_set(node, tag, 0); |
|
} |
|
} |
|
|
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BUG_ON(shift > BITS_PER_LONG); |
|
if (radix_tree_is_internal_node(entry)) { |
|
entry_to_node(entry)->parent = node; |
|
} else if (xa_is_value(entry)) { |
|
/* Moving a value entry root->xa_head to a node */ |
|
node->nr_values = 1; |
|
} |
|
/* |
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* entry was already in the radix tree, so we do not need |
|
* rcu_assign_pointer here |
|
*/ |
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node->slots[0] = (void __rcu *)entry; |
|
entry = node_to_entry(node); |
|
rcu_assign_pointer(root->xa_head, 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) |
|
{ |
|
bool shrunk = false; |
|
|
|
for (;;) { |
|
struct radix_tree_node *node = rcu_dereference_raw(root->xa_head); |
|
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, we cannot shrink. |
|
*/ |
|
if (node->count != 1) |
|
break; |
|
child = rcu_dereference_raw(node->slots[0]); |
|
if (!child) |
|
break; |
|
|
|
/* |
|
* For an IDR, we must not shrink entry 0 into the root in |
|
* case somebody calls idr_replace() with a pointer that |
|
* appears to be an internal entry |
|
*/ |
|
if (!node->shift && is_idr(root)) |
|
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->xa_head) as far as dependent read barriers go. |
|
*/ |
|
root->xa_head = (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; |
|
} |
|
|
|
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) |
|
{ |
|
bool deleted = false; |
|
|
|
do { |
|
struct radix_tree_node *parent; |
|
|
|
if (node->count) { |
|
if (node_to_entry(node) == |
|
rcu_dereference_raw(root->xa_head)) |
|
deleted |= radix_tree_shrink(root); |
|
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->xa_head = 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 |
|
* @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->xa_head 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. |
|
*/ |
|
static int __radix_tree_create(struct radix_tree_root *root, |
|
unsigned long index, struct radix_tree_node **nodep, |
|
void __rcu ***slotp) |
|
{ |
|
struct radix_tree_node *node = NULL, *child; |
|
void __rcu **slot = (void __rcu **)&root->xa_head; |
|
unsigned long maxindex; |
|
unsigned int shift, offset = 0; |
|
unsigned long max = index; |
|
gfp_t gfp = root_gfp_mask(root); |
|
|
|
shift = radix_tree_load_root(root, &child, &maxindex); |
|
|
|
/* Make sure the tree is high enough. */ |
|
if (max > maxindex) { |
|
int error = radix_tree_extend(root, gfp, max, shift); |
|
if (error < 0) |
|
return error; |
|
shift = error; |
|
child = rcu_dereference_raw(root->xa_head); |
|
} |
|
|
|
while (shift > 0) { |
|
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 (xa_is_node(entry) && child->shift) { |
|
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; |
|
} |
|
} |
|
} |
|
|
|
static inline int insert_entries(struct radix_tree_node *node, |
|
void __rcu **slot, void *item, bool replace) |
|
{ |
|
if (*slot) |
|
return -EEXIST; |
|
rcu_assign_pointer(*slot, item); |
|
if (node) { |
|
node->count++; |
|
if (xa_is_value(item)) |
|
node->nr_values++; |
|
} |
|
return 1; |
|
} |
|
|
|
/** |
|
* radix_tree_insert - insert into a radix tree |
|
* @root: radix tree root |
|
* @index: index key |
|
* @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, |
|
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, &node, &slot); |
|
if (error) |
|
return error; |
|
|
|
error = insert_entries(node, slot, item, 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->xa_head 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->xa_head; |
|
radix_tree_load_root(root, &node, &maxindex); |
|
if (index > maxindex) |
|
return NULL; |
|
|
|
while (radix_tree_is_internal_node(node)) { |
|
unsigned offset; |
|
|
|
parent = entry_to_node(node); |
|
offset = radix_tree_descend(parent, &node, index); |
|
slot = parent->slots + offset; |
|
if (node == RADIX_TREE_RETRY) |
|
goto restart; |
|
if (parent->shift == 0) |
|
break; |
|
} |
|
|
|
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 void replace_slot(void __rcu **slot, void *item, |
|
struct radix_tree_node *node, int count, int values) |
|
{ |
|
if (node && (count || values)) { |
|
node->count += count; |
|
node->nr_values += values; |
|
} |
|
|
|
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. |
|
* |
|
* 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) |
|
{ |
|
void *old = rcu_dereference_raw(*slot); |
|
int values = !!xa_is_value(item) - !!xa_is_value(old); |
|
int count = calculate_count(root, node, slot, item, old); |
|
|
|
/* |
|
* This function supports replacing value entries and |
|
* deleting entries, but that needs accounting against the |
|
* node unless the slot is root->xa_head. |
|
*/ |
|
WARN_ON_ONCE(!node && (slot != (void __rcu **)&root->xa_head) && |
|
(count || values)); |
|
replace_slot(slot, item, node, count, values); |
|
|
|
if (!node) |
|
return; |
|
|
|
delete_node(root, node); |
|
} |
|
|
|
/** |
|
* 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() and |
|
* 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 value 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); |
|
} |
|
EXPORT_SYMBOL(radix_tree_replace_slot); |
|
|
|
/** |
|
* radix_tree_iter_replace - replace item in a slot |
|
* @root: radix tree root |
|
* @iter: iterator state |
|
* @slot: pointer to slot |
|
* @item: new item to store in the slot. |
|
* |
|
* For use with radix_tree_for_each_slot(). |
|
* Caller must hold tree write locked. |
|
*/ |
|
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); |
|
} |
|
|
|
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); |
|
|
|
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 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); |
|
|
|
/* 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); |
|
} |
|
} |
|
|
|
void __rcu **radix_tree_iter_resume(void __rcu **slot, |
|
struct radix_tree_iter *iter) |
|
{ |
|
slot++; |
|
iter->index = __radix_tree_iter_add(iter, 1); |
|
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; |
|
return (void __rcu **)&root->xa_head; |
|
} |
|
|
|
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 (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 (node->shift && radix_tree_is_internal_node(child)); |
|
|
|
/* Update the iterator state */ |
|
iter->index = (index &~ node_maxindex(node)) | offset; |
|
iter->next_index = (index | node_maxindex(node)) + 1; |
|
iter->node = node; |
|
|
|
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_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); |
|
|
|
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 values = xa_is_value(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, values); |
|
return node && delete_node(root, node); |
|
} |
|
|
|
/** |
|
* 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); |
|
|
|
/** |
|
* 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)) |
|
local_lock(&radix_tree_preloads.lock); |
|
} |
|
EXPORT_SYMBOL(idr_preload); |
|
|
|
void __rcu **idr_get_free(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->xa_head; |
|
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->xa_head); |
|
} |
|
if (start == 0 && shift == 0) |
|
shift = RADIX_TREE_MAP_SHIFT; |
|
|
|
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_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.xa_head); |
|
if (radix_tree_is_internal_node(node)) |
|
radix_tree_free_nodes(node); |
|
idr->idr_rt.xa_head = 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 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--; |
|
} |
|
return 0; |
|
} |
|
|
|
void __init radix_tree_init(void) |
|
{ |
|
int ret; |
|
|
|
BUILD_BUG_ON(RADIX_TREE_MAX_TAGS + __GFP_BITS_SHIFT > 32); |
|
BUILD_BUG_ON(ROOT_IS_IDR & ~GFP_ZONEMASK); |
|
BUILD_BUG_ON(XA_CHUNK_SIZE > 255); |
|
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); |
|
ret = cpuhp_setup_state_nocalls(CPUHP_RADIX_DEAD, "lib/radix:dead", |
|
NULL, radix_tree_cpu_dead); |
|
WARN_ON(ret < 0); |
|
}
|
|
|