diff options
Diffstat (limited to 'include/linux/radix-tree.h')
| -rw-r--r-- | include/linux/radix-tree.h | 174 |
1 files changed, 86 insertions, 88 deletions
diff --git a/include/linux/radix-tree.h b/include/linux/radix-tree.h index 744486057e9e..5dea8f6440e4 100644 --- a/include/linux/radix-tree.h +++ b/include/linux/radix-tree.h @@ -80,23 +80,25 @@ 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)) +/* + * @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 char count; /* Total entry count */ unsigned char exceptional; /* Exceptional entry count */ + struct radix_tree_node *parent; /* Used when ascending tree */ + void *private_data; /* For tree user */ 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]; }; @@ -127,6 +129,41 @@ static inline bool radix_tree_empty(struct radix_tree_root *root) } /** + * 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 @@ -264,6 +301,8 @@ void __radix_tree_replace(struct radix_tree_root *root, struct radix_tree_node *node, void **slot, void *item, radix_tree_update_node_t update_node, void *private); +void radix_tree_iter_replace(struct radix_tree_root *, + const struct radix_tree_iter *, void **slot, void *item); void radix_tree_replace_slot(struct radix_tree_root *root, void **slot, void *item); void __radix_tree_delete_node(struct radix_tree_root *root, @@ -289,6 +328,8 @@ void *radix_tree_tag_clear(struct radix_tree_root *root, unsigned long index, unsigned int tag); int radix_tree_tag_get(struct radix_tree_root *root, unsigned long index, unsigned int tag); +void radix_tree_iter_tag_set(struct radix_tree_root *root, + const struct radix_tree_iter *iter, 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, @@ -297,50 +338,18 @@ 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); 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 -}; - -static inline unsigned int iter_shift(struct radix_tree_iter *iter) -{ -#ifdef CONFIG_RADIX_TREE_MULTIORDER - return iter->shift; -#else - return 0; -#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 *); #define RADIX_TREE_ITER_TAG_MASK 0x00FF /* tag index in lower byte */ #define RADIX_TREE_ITER_TAGGED 0x0100 /* lookup tagged slots */ @@ -409,20 +418,17 @@ __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 **__must_check radix_tree_iter_resume(void **slot, + struct radix_tree_iter *iter); /** * radix_tree_chunk_size - get current chunk size @@ -436,10 +442,17 @@ 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 ** __radix_tree_next_slot(void **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 ** __radix_tree_next_slot(void **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 @@ -453,7 +466,7 @@ 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 @@ -464,51 +477,31 @@ static __always_inline void ** radix_tree_next_slot(void **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; @@ -517,6 +510,11 @@ radix_tree_next_slot(void **slot, struct radix_tree_iter *iter, unsigned flags) } } return NULL; + + found: + if (unlikely(radix_tree_is_internal_node(*slot))) + return __radix_tree_next_slot(slot, iter, flags); + return slot; } /** @@ -567,6 +565,6 @@ 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 */ |