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| author | Matthew Wilcox <willy@linux.intel.com> | 2016-12-14 15:09:01 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2016-12-14 16:04:10 -0800 |
| commit | e157b555945fb16ddc6cce605a1eb6b4135ea5f1 (patch) | |
| tree | f0b53b641059c010cfd38a32ae7f4f3b27b04303 /include | |
| parent | 175542f575723e43f897ddb09d0011c13f7cf0ec (diff) | |
| download | linux-e157b555945fb16ddc6cce605a1eb6b4135ea5f1.tar.bz2 | |
radix-tree: add radix_tree_split
This new function splits a larger multiorder entry into smaller entries
(potentially multi-order entries). These entries are initialised to
RADIX_TREE_RETRY to ensure that RCU walkers who see this state aren't
confused. The caller should then call radix_tree_for_each_slot() and
radix_tree_replace_slot() in order to turn these retry entries into the
intended new entries. Tags are replicated from the original multiorder
entry into each new entry.
Link: http://lkml.kernel.org/r/1480369871-5271-59-git-send-email-mawilcox@linuxonhyperv.com
Signed-off-by: Matthew Wilcox <willy@linux.intel.com>
Tested-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Konstantin Khlebnikov <koct9i@gmail.com>
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Cc: Matthew Wilcox <mawilcox@microsoft.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'include')
| -rw-r--r-- | include/linux/radix-tree.h | 12 |
1 files changed, 12 insertions, 0 deletions
diff --git a/include/linux/radix-tree.h b/include/linux/radix-tree.h index 935293a24f7d..1f4b56120de8 100644 --- a/include/linux/radix-tree.h +++ b/include/linux/radix-tree.h @@ -80,6 +80,14 @@ 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 */ @@ -293,6 +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, @@ -335,6 +345,8 @@ static inline void radix_tree_preload_end(void) preempt_enable(); } +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 *); |