diff options
Diffstat (limited to 'include/linux/radix-tree.h')
| -rw-r--r-- | include/linux/radix-tree.h | 361 |
1 files changed, 198 insertions, 163 deletions
diff --git a/include/linux/radix-tree.h b/include/linux/radix-tree.h index af3581b8a451..3e5735064b71 100644 --- a/include/linux/radix-tree.h +++ b/include/linux/radix-tree.h @@ -22,11 +22,13 @@ #define _LINUX_RADIX_TREE_H #include <linux/bitops.h> -#include <linux/preempt.h> -#include <linux/types.h> #include <linux/bug.h> #include <linux/kernel.h> +#include <linux/list.h> +#include <linux/preempt.h> #include <linux/rcupdate.h> +#include <linux/spinlock.h> +#include <linux/types.h> /* * The bottom two bits of the slot determine how the remaining bits in the @@ -80,31 +82,33 @@ static inline bool radix_tree_is_internal_node(void *ptr) #define RADIX_TREE_MAX_PATH (DIV_ROUND_UP(RADIX_TREE_INDEX_BITS, \ RADIX_TREE_MAP_SHIFT)) -/* Internally used bits of node->count */ -#define RADIX_TREE_COUNT_SHIFT (RADIX_TREE_MAP_SHIFT + 1) -#define RADIX_TREE_COUNT_MASK ((1UL << RADIX_TREE_COUNT_SHIFT) - 1) - +/* + * @count is the count of every non-NULL element in the ->slots array + * whether that is an exceptional entry, a retry entry, a user pointer, + * a sibling entry or a pointer to the next level of the tree. + * @exceptional is the count of every element in ->slots which is + * either radix_tree_exceptional_entry() or is a sibling entry for an + * exceptional entry. + */ struct radix_tree_node { - unsigned char shift; /* Bits remaining in each slot */ - unsigned char offset; /* Slot offset in parent */ - unsigned int count; + unsigned char shift; /* Bits remaining in each slot */ + unsigned char offset; /* Slot offset in parent */ + unsigned char count; /* Total entry count */ + unsigned char exceptional; /* Exceptional entry count */ + struct radix_tree_node *parent; /* Used when ascending tree */ + struct radix_tree_root *root; /* The tree we belong to */ union { - struct { - /* Used when ascending tree */ - struct radix_tree_node *parent; - /* For tree user */ - void *private_data; - }; - /* Used when freeing node */ - struct rcu_head rcu_head; + struct list_head private_list; /* For tree user */ + struct rcu_head rcu_head; /* Used when freeing node */ }; - /* For tree user */ - struct list_head private_list; void __rcu *slots[RADIX_TREE_MAP_SIZE]; unsigned long tags[RADIX_TREE_MAX_TAGS][RADIX_TREE_TAG_LONGS]; }; -/* root tags are stored in gfp_mask, shifted by __GFP_BITS_SHIFT */ +/* The top bits of gfp_mask are used to store the root tags and the IDR flag */ +#define ROOT_IS_IDR ((__force gfp_t)(1 << __GFP_BITS_SHIFT)) +#define ROOT_TAG_SHIFT (__GFP_BITS_SHIFT + 1) + struct radix_tree_root { gfp_t gfp_mask; struct radix_tree_node __rcu *rnode; @@ -124,12 +128,47 @@ do { \ (root)->rnode = NULL; \ } while (0) -static inline bool radix_tree_empty(struct radix_tree_root *root) +static inline bool radix_tree_empty(const struct radix_tree_root *root) { return root->rnode == NULL; } /** + * struct radix_tree_iter - radix tree iterator state + * + * @index: index of current slot + * @next_index: one beyond the last index for this chunk + * @tags: bit-mask for tag-iterating + * @node: node that contains current slot + * @shift: shift for the node that holds our slots + * + * This radix tree iterator works in terms of "chunks" of slots. A chunk is a + * subinterval of slots contained within one radix tree leaf node. It is + * described by a pointer to its first slot and a struct radix_tree_iter + * which holds the chunk's position in the tree and its size. For tagged + * iteration radix_tree_iter also holds the slots' bit-mask for one chosen + * radix tree tag. + */ +struct radix_tree_iter { + unsigned long index; + unsigned long next_index; + unsigned long tags; + struct radix_tree_node *node; +#ifdef CONFIG_RADIX_TREE_MULTIORDER + unsigned int shift; +#endif +}; + +static inline unsigned int iter_shift(const struct radix_tree_iter *iter) +{ +#ifdef CONFIG_RADIX_TREE_MULTIORDER + return iter->shift; +#else + return 0; +#endif +} + +/** * Radix-tree synchronization * * The radix-tree API requires that users provide all synchronisation (with @@ -182,10 +221,8 @@ static inline bool radix_tree_empty(struct radix_tree_root *root) */ /** - * radix_tree_deref_slot - dereference a slot - * @pslot: pointer to slot, returned by radix_tree_lookup_slot - * Returns: item that was stored in that slot with any direct pointer flag - * removed. + * radix_tree_deref_slot - dereference a slot + * @slot: slot pointer, returned by radix_tree_lookup_slot * * For use with radix_tree_lookup_slot(). Caller must hold tree at least read * locked across slot lookup and dereference. Not required if write lock is @@ -193,26 +230,27 @@ static inline bool radix_tree_empty(struct radix_tree_root *root) * * radix_tree_deref_retry must be used to confirm validity of the pointer if * only the read lock is held. + * + * Return: entry stored in that slot. */ -static inline void *radix_tree_deref_slot(void **pslot) +static inline void *radix_tree_deref_slot(void __rcu **slot) { - return rcu_dereference(*pslot); + return rcu_dereference(*slot); } /** - * radix_tree_deref_slot_protected - dereference a slot without RCU lock but with tree lock held - * @pslot: pointer to slot, returned by radix_tree_lookup_slot - * Returns: item that was stored in that slot with any direct pointer flag - * removed. - * - * Similar to radix_tree_deref_slot but only used during migration when a pages - * mapping is being moved. The caller does not hold the RCU read lock but it - * must hold the tree lock to prevent parallel updates. + * radix_tree_deref_slot_protected - dereference a slot with tree lock held + * @slot: slot pointer, returned by radix_tree_lookup_slot + * + * Similar to radix_tree_deref_slot. The caller does not hold the RCU read + * lock but it must hold the tree lock to prevent parallel updates. + * + * Return: entry stored in that slot. */ -static inline void *radix_tree_deref_slot_protected(void **pslot, +static inline void *radix_tree_deref_slot_protected(void __rcu **slot, spinlock_t *treelock) { - return rcu_dereference_protected(*pslot, lockdep_is_held(treelock)); + return rcu_dereference_protected(*slot, lockdep_is_held(treelock)); } /** @@ -248,23 +286,9 @@ static inline int radix_tree_exception(void *arg) return unlikely((unsigned long)arg & RADIX_TREE_ENTRY_MASK); } -/** - * radix_tree_replace_slot - replace item in a slot - * @pslot: pointer to slot, returned by radix_tree_lookup_slot - * @item: new item to store in the slot. - * - * For use with radix_tree_lookup_slot(). Caller must hold tree write locked - * across slot lookup and replacement. - */ -static inline void radix_tree_replace_slot(void **pslot, void *item) -{ - BUG_ON(radix_tree_is_internal_node(item)); - rcu_assign_pointer(*pslot, item); -} - -int __radix_tree_create(struct radix_tree_root *root, unsigned long index, +int __radix_tree_create(struct radix_tree_root *, unsigned long index, unsigned order, struct radix_tree_node **nodep, - void ***slotp); + void __rcu ***slotp); int __radix_tree_insert(struct radix_tree_root *, unsigned long index, unsigned order, void *); static inline int radix_tree_insert(struct radix_tree_root *root, @@ -272,90 +296,76 @@ static inline int radix_tree_insert(struct radix_tree_root *root, { return __radix_tree_insert(root, index, 0, entry); } -void *__radix_tree_lookup(struct radix_tree_root *root, unsigned long index, - struct radix_tree_node **nodep, void ***slotp); -void *radix_tree_lookup(struct radix_tree_root *, unsigned long); -void **radix_tree_lookup_slot(struct radix_tree_root *, unsigned long); -bool __radix_tree_delete_node(struct radix_tree_root *root, - struct radix_tree_node *node); +void *__radix_tree_lookup(const struct radix_tree_root *, unsigned long index, + struct radix_tree_node **nodep, void __rcu ***slotp); +void *radix_tree_lookup(const struct radix_tree_root *, unsigned long); +void __rcu **radix_tree_lookup_slot(const struct radix_tree_root *, + unsigned long index); +typedef void (*radix_tree_update_node_t)(struct radix_tree_node *, void *); +void __radix_tree_replace(struct radix_tree_root *, struct radix_tree_node *, + void __rcu **slot, void *entry, + radix_tree_update_node_t update_node, void *private); +void radix_tree_iter_replace(struct radix_tree_root *, + const struct radix_tree_iter *, void __rcu **slot, void *entry); +void radix_tree_replace_slot(struct radix_tree_root *, + void __rcu **slot, void *entry); +void __radix_tree_delete_node(struct radix_tree_root *, + struct radix_tree_node *, + radix_tree_update_node_t update_node, + void *private); +void radix_tree_iter_delete(struct radix_tree_root *, + struct radix_tree_iter *iter, void __rcu **slot); void *radix_tree_delete_item(struct radix_tree_root *, unsigned long, void *); void *radix_tree_delete(struct radix_tree_root *, unsigned long); -void radix_tree_clear_tags(struct radix_tree_root *root, - struct radix_tree_node *node, - void **slot); -unsigned int radix_tree_gang_lookup(struct radix_tree_root *root, +void radix_tree_clear_tags(struct radix_tree_root *, struct radix_tree_node *, + void __rcu **slot); +unsigned int radix_tree_gang_lookup(const struct radix_tree_root *, void **results, unsigned long first_index, unsigned int max_items); -unsigned int radix_tree_gang_lookup_slot(struct radix_tree_root *root, - void ***results, unsigned long *indices, +unsigned int radix_tree_gang_lookup_slot(const struct radix_tree_root *, + void __rcu ***results, unsigned long *indices, unsigned long first_index, unsigned int max_items); int radix_tree_preload(gfp_t gfp_mask); int radix_tree_maybe_preload(gfp_t gfp_mask); int radix_tree_maybe_preload_order(gfp_t gfp_mask, int order); void radix_tree_init(void); -void *radix_tree_tag_set(struct radix_tree_root *root, +void *radix_tree_tag_set(struct radix_tree_root *, unsigned long index, unsigned int tag); -void *radix_tree_tag_clear(struct radix_tree_root *root, +void *radix_tree_tag_clear(struct radix_tree_root *, unsigned long index, unsigned int tag); -int radix_tree_tag_get(struct radix_tree_root *root, +int radix_tree_tag_get(const struct radix_tree_root *, unsigned long index, unsigned int tag); -unsigned int -radix_tree_gang_lookup_tag(struct radix_tree_root *root, void **results, - unsigned long first_index, unsigned int max_items, - unsigned int tag); -unsigned int -radix_tree_gang_lookup_tag_slot(struct radix_tree_root *root, void ***results, - unsigned long first_index, unsigned int max_items, - unsigned int tag); -unsigned long radix_tree_range_tag_if_tagged(struct radix_tree_root *root, - unsigned long *first_indexp, unsigned long last_index, - unsigned long nr_to_tag, - unsigned int fromtag, unsigned int totag); -int radix_tree_tagged(struct radix_tree_root *root, unsigned int tag); -unsigned long radix_tree_locate_item(struct radix_tree_root *root, void *item); +void radix_tree_iter_tag_set(struct radix_tree_root *, + const struct radix_tree_iter *iter, unsigned int tag); +void radix_tree_iter_tag_clear(struct radix_tree_root *, + const struct radix_tree_iter *iter, unsigned int tag); +unsigned int radix_tree_gang_lookup_tag(const struct radix_tree_root *, + void **results, unsigned long first_index, + unsigned int max_items, unsigned int tag); +unsigned int radix_tree_gang_lookup_tag_slot(const struct radix_tree_root *, + void __rcu ***results, unsigned long first_index, + unsigned int max_items, unsigned int tag); +int radix_tree_tagged(const struct radix_tree_root *, unsigned int tag); static inline void radix_tree_preload_end(void) { preempt_enable(); } -/** - * struct radix_tree_iter - radix tree iterator state - * - * @index: index of current slot - * @next_index: one beyond the last index for this chunk - * @tags: bit-mask for tag-iterating - * @shift: shift for the node that holds our slots - * - * This radix tree iterator works in terms of "chunks" of slots. A chunk is a - * subinterval of slots contained within one radix tree leaf node. It is - * described by a pointer to its first slot and a struct radix_tree_iter - * which holds the chunk's position in the tree and its size. For tagged - * iteration radix_tree_iter also holds the slots' bit-mask for one chosen - * radix tree tag. - */ -struct radix_tree_iter { - unsigned long index; - unsigned long next_index; - unsigned long tags; -#ifdef CONFIG_RADIX_TREE_MULTIORDER - unsigned int shift; -#endif +int radix_tree_split_preload(unsigned old_order, unsigned new_order, gfp_t); +int radix_tree_split(struct radix_tree_root *, unsigned long index, + unsigned new_order); +int radix_tree_join(struct radix_tree_root *, unsigned long index, + unsigned new_order, void *); +void __rcu **idr_get_free(struct radix_tree_root *, struct radix_tree_iter *, + gfp_t, int end); + +enum { + RADIX_TREE_ITER_TAG_MASK = 0x0f, /* tag index in lower nybble */ + RADIX_TREE_ITER_TAGGED = 0x10, /* lookup tagged slots */ + RADIX_TREE_ITER_CONTIG = 0x20, /* stop at first hole */ }; -static inline unsigned int iter_shift(struct radix_tree_iter *iter) -{ -#ifdef CONFIG_RADIX_TREE_MULTIORDER - return iter->shift; -#else - return 0; -#endif -} - -#define RADIX_TREE_ITER_TAG_MASK 0x00FF /* tag index in lower byte */ -#define RADIX_TREE_ITER_TAGGED 0x0100 /* lookup tagged slots */ -#define RADIX_TREE_ITER_CONTIG 0x0200 /* stop at first hole */ - /** * radix_tree_iter_init - initialize radix tree iterator * @@ -363,7 +373,7 @@ static inline unsigned int iter_shift(struct radix_tree_iter *iter) * @start: iteration starting index * Returns: NULL */ -static __always_inline void ** +static __always_inline void __rcu ** radix_tree_iter_init(struct radix_tree_iter *iter, unsigned long start) { /* @@ -392,10 +402,46 @@ radix_tree_iter_init(struct radix_tree_iter *iter, unsigned long start) * Also it fills @iter with data about chunk: position in the tree (index), * its end (next_index), and constructs a bit mask for tagged iterating (tags). */ -void **radix_tree_next_chunk(struct radix_tree_root *root, +void __rcu **radix_tree_next_chunk(const struct radix_tree_root *, struct radix_tree_iter *iter, unsigned flags); /** + * radix_tree_iter_lookup - look up an index in the radix tree + * @root: radix tree root + * @iter: iterator state + * @index: key to look up + * + * If @index is present in the radix tree, this function returns the slot + * containing it and updates @iter to describe the entry. If @index is not + * present, it returns NULL. + */ +static inline void __rcu ** +radix_tree_iter_lookup(const struct radix_tree_root *root, + struct radix_tree_iter *iter, unsigned long index) +{ + radix_tree_iter_init(iter, index); + return radix_tree_next_chunk(root, iter, RADIX_TREE_ITER_CONTIG); +} + +/** + * radix_tree_iter_find - find a present entry + * @root: radix tree root + * @iter: iterator state + * @index: start location + * + * This function returns the slot containing the entry with the lowest index + * which is at least @index. If @index is larger than any present entry, this + * function returns NULL. The @iter is updated to describe the entry found. + */ +static inline void __rcu ** +radix_tree_iter_find(const struct radix_tree_root *root, + struct radix_tree_iter *iter, unsigned long index) +{ + radix_tree_iter_init(iter, index); + return radix_tree_next_chunk(root, iter, 0); +} + +/** * radix_tree_iter_retry - retry this chunk of the iteration * @iter: iterator state * @@ -405,7 +451,7 @@ void **radix_tree_next_chunk(struct radix_tree_root *root, * and continue the iteration. */ static inline __must_check -void **radix_tree_iter_retry(struct radix_tree_iter *iter) +void __rcu **radix_tree_iter_retry(struct radix_tree_iter *iter) { iter->next_index = iter->index; iter->tags = 0; @@ -419,20 +465,17 @@ __radix_tree_iter_add(struct radix_tree_iter *iter, unsigned long slots) } /** - * radix_tree_iter_next - resume iterating when the chunk may be invalid - * @iter: iterator state + * radix_tree_iter_resume - resume iterating when the chunk may be invalid + * @slot: pointer to current slot + * @iter: iterator state + * Returns: New slot pointer * * If the iterator needs to release then reacquire a lock, the chunk may * have been invalidated by an insertion or deletion. Call this function - * to continue the iteration from the next index. + * before releasing the lock to continue the iteration from the next index. */ -static inline __must_check -void **radix_tree_iter_next(struct radix_tree_iter *iter) -{ - iter->next_index = __radix_tree_iter_add(iter, 1); - iter->tags = 0; - return NULL; -} +void __rcu **__must_check radix_tree_iter_resume(void __rcu **slot, + struct radix_tree_iter *iter); /** * radix_tree_chunk_size - get current chunk size @@ -446,10 +489,17 @@ radix_tree_chunk_size(struct radix_tree_iter *iter) return (iter->next_index - iter->index) >> iter_shift(iter); } -static inline struct radix_tree_node *entry_to_node(void *ptr) +#ifdef CONFIG_RADIX_TREE_MULTIORDER +void __rcu **__radix_tree_next_slot(void __rcu **slot, + struct radix_tree_iter *iter, unsigned flags); +#else +/* Can't happen without sibling entries, but the compiler can't tell that */ +static inline void __rcu **__radix_tree_next_slot(void __rcu **slot, + struct radix_tree_iter *iter, unsigned flags) { - return (void *)((unsigned long)ptr & ~RADIX_TREE_INTERNAL_NODE); + return slot; } +#endif /** * radix_tree_next_slot - find next slot in chunk @@ -463,62 +513,42 @@ static inline struct radix_tree_node *entry_to_node(void *ptr) * For tagged lookup it also eats @iter->tags. * * There are several cases where 'slot' can be passed in as NULL to this - * function. These cases result from the use of radix_tree_iter_next() or + * function. These cases result from the use of radix_tree_iter_resume() or * radix_tree_iter_retry(). In these cases we don't end up dereferencing * 'slot' because either: * a) we are doing tagged iteration and iter->tags has been set to 0, or * b) we are doing non-tagged iteration, and iter->index and iter->next_index * have been set up so that radix_tree_chunk_size() returns 1 or 0. */ -static __always_inline void ** -radix_tree_next_slot(void **slot, struct radix_tree_iter *iter, unsigned flags) +static __always_inline void __rcu **radix_tree_next_slot(void __rcu **slot, + struct radix_tree_iter *iter, unsigned flags) { if (flags & RADIX_TREE_ITER_TAGGED) { - void *canon = slot; - iter->tags >>= 1; if (unlikely(!iter->tags)) return NULL; - while (IS_ENABLED(CONFIG_RADIX_TREE_MULTIORDER) && - radix_tree_is_internal_node(slot[1])) { - if (entry_to_node(slot[1]) == canon) { - iter->tags >>= 1; - iter->index = __radix_tree_iter_add(iter, 1); - slot++; - continue; - } - iter->next_index = __radix_tree_iter_add(iter, 1); - return NULL; - } if (likely(iter->tags & 1ul)) { iter->index = __radix_tree_iter_add(iter, 1); - return slot + 1; + slot++; + goto found; } if (!(flags & RADIX_TREE_ITER_CONTIG)) { unsigned offset = __ffs(iter->tags); - iter->tags >>= offset; - iter->index = __radix_tree_iter_add(iter, offset + 1); - return slot + offset + 1; + iter->tags >>= offset++; + iter->index = __radix_tree_iter_add(iter, offset); + slot += offset; + goto found; } } else { long count = radix_tree_chunk_size(iter); - void *canon = slot; while (--count > 0) { slot++; iter->index = __radix_tree_iter_add(iter, 1); - if (IS_ENABLED(CONFIG_RADIX_TREE_MULTIORDER) && - radix_tree_is_internal_node(*slot)) { - if (entry_to_node(*slot) == canon) - continue; - iter->next_index = iter->index; - break; - } - if (likely(*slot)) - return slot; + goto found; if (flags & RADIX_TREE_ITER_CONTIG) { /* forbid switching to the next chunk */ iter->next_index = 0; @@ -527,6 +557,11 @@ radix_tree_next_slot(void **slot, struct radix_tree_iter *iter, unsigned flags) } } return NULL; + + found: + if (unlikely(radix_tree_is_internal_node(rcu_dereference_raw(*slot)))) + return __radix_tree_next_slot(slot, iter, flags); + return slot; } /** @@ -577,6 +612,6 @@ radix_tree_next_slot(void **slot, struct radix_tree_iter *iter, unsigned flags) slot || (slot = radix_tree_next_chunk(root, iter, \ RADIX_TREE_ITER_TAGGED | tag)) ; \ slot = radix_tree_next_slot(slot, iter, \ - RADIX_TREE_ITER_TAGGED)) + RADIX_TREE_ITER_TAGGED | tag)) #endif /* _LINUX_RADIX_TREE_H */ |
