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c95c2d328c
Fix various kernel-doc warnings in lib/ due to missing or erroneous function names. Add kernel-doc for some function parameters that was missing. Use kernel-doc "Return:" notation in earlycpio.c. Quietens the following warnings: lib/earlycpio.c:61: warning: expecting prototype for cpio_data find_cpio_data(). Prototype was for find_cpio_data() instead lib/lru_cache.c:640: warning: expecting prototype for lc_dump(). Prototype was for lc_seq_dump_details() instead lru_cache.c:90: warning: Function parameter or member 'cache' not described in 'lc_create' lib/parman.c:368: warning: expecting prototype for parman_item_del(). Prototype was for parman_item_remove() instead parman.c:309: warning: Excess function parameter 'prority' description in 'parman_prio_init' lib/radix-tree.c:703: warning: expecting prototype for __radix_tree_insert(). Prototype was for radix_tree_insert() instead radix-tree.c:180: warning: Excess function parameter 'addr' description in 'radix_tree_find_next_bit' radix-tree.c:180: warning: Excess function parameter 'size' description in 'radix_tree_find_next_bit' radix-tree.c:931: warning: Function parameter or member 'iter' not described in 'radix_tree_iter_replace' Link: https://lkml.kernel.org/r/20210411221756.15461-1-rdunlap@infradead.org Signed-off-by: Randy Dunlap <rdunlap@infradead.org> Cc: Philipp Reisner <philipp.reisner@linbit.com> Cc: Lars Ellenberg <lars.ellenberg@linbit.com> Cc: Jiri Pirko <jiri@nvidia.com> Cc: Matthew Wilcox <willy@infradead.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
1608 lines
43 KiB
C
1608 lines
43 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/*
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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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#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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* 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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* 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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* 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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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 XA_RETRY_ENTRY
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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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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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*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->xa_flags & (__GFP_BITS_MASK & ~GFP_ZONEMASK);
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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->xa_flags |= (__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->xa_flags &= (__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->xa_flags &= (__force gfp_t)((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->xa_flags & (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->xa_flags >> 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->xa_flags & 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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* @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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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 & 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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/*
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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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* 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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* 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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* 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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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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* 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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kmem_cache_free(radix_tree_node_cachep, node);
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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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* 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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* 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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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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* 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 */
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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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}
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*maxindex = 0;
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return 0;
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}
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|
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/*
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* Extend a radix tree so it can store key @index.
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*/
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static int radix_tree_extend(struct radix_tree_root *root, gfp_t gfp,
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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;
|
|
|
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/* 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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|
|
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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;
|
|
|
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if (is_idr(root)) {
|
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all_tag_set(node, IDR_FREE);
|
|
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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}
|
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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))
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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 (xa_is_value(entry)) {
|
|
/* Moving a value entry root->xa_head to a node */
|
|
node->nr_values = 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->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);
|
|
}
|