From: Chuck Lever <chuck.lever@xxxxxxxxxx> commit 9b6713cc75229f25552c643083cbdbfb771e5bca upstream. I need a cyclic allocator for the simple_offset implementation in fs/libfs.c. Signed-off-by: Chuck Lever <chuck.lever@xxxxxxxxxx> Link: https://lore.kernel.org/r/170820144179.6328.12838600511394432325.stgit@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx Signed-off-by: Christian Brauner <brauner@xxxxxxxxxx> Signed-off-by: Yu Kuai <yukuai3@xxxxxxxxxx> --- include/linux/maple_tree.h | 7 +++ lib/maple_tree.c | 93 ++++++++++++++++++++++++++++++++++++++ 2 files changed, 100 insertions(+) diff --git a/include/linux/maple_tree.h b/include/linux/maple_tree.h index b3d63123b945..a53ad4dabd7e 100644 --- a/include/linux/maple_tree.h +++ b/include/linux/maple_tree.h @@ -171,6 +171,7 @@ enum maple_type { #define MT_FLAGS_LOCK_IRQ 0x100 #define MT_FLAGS_LOCK_BH 0x200 #define MT_FLAGS_LOCK_EXTERN 0x300 +#define MT_FLAGS_ALLOC_WRAPPED 0x0800 #define MAPLE_HEIGHT_MAX 31 @@ -319,6 +320,9 @@ int mtree_insert_range(struct maple_tree *mt, unsigned long first, int mtree_alloc_range(struct maple_tree *mt, unsigned long *startp, void *entry, unsigned long size, unsigned long min, unsigned long max, gfp_t gfp); +int mtree_alloc_cyclic(struct maple_tree *mt, unsigned long *startp, + void *entry, unsigned long range_lo, unsigned long range_hi, + unsigned long *next, gfp_t gfp); int mtree_alloc_rrange(struct maple_tree *mt, unsigned long *startp, void *entry, unsigned long size, unsigned long min, unsigned long max, gfp_t gfp); @@ -499,6 +503,9 @@ void *mas_find_range(struct ma_state *mas, unsigned long max); void *mas_find_rev(struct ma_state *mas, unsigned long min); void *mas_find_range_rev(struct ma_state *mas, unsigned long max); int mas_preallocate(struct ma_state *mas, void *entry, gfp_t gfp); +int mas_alloc_cyclic(struct ma_state *mas, unsigned long *startp, + void *entry, unsigned long range_lo, unsigned long range_hi, + unsigned long *next, gfp_t gfp); bool mas_nomem(struct ma_state *mas, gfp_t gfp); void mas_pause(struct ma_state *mas); diff --git a/lib/maple_tree.c b/lib/maple_tree.c index 1af83414877a..5328e08723d7 100644 --- a/lib/maple_tree.c +++ b/lib/maple_tree.c @@ -4337,6 +4337,56 @@ static inline void *mas_insert(struct ma_state *mas, void *entry) } +/** + * mas_alloc_cyclic() - Internal call to find somewhere to store an entry + * @mas: The maple state. + * @startp: Pointer to ID. + * @range_lo: Lower bound of range to search. + * @range_hi: Upper bound of range to search. + * @entry: The entry to store. + * @next: Pointer to next ID to allocate. + * @gfp: The GFP_FLAGS to use for allocations. + * + * Return: 0 if the allocation succeeded without wrapping, 1 if the + * allocation succeeded after wrapping, or -EBUSY if there are no + * free entries. + */ +int mas_alloc_cyclic(struct ma_state *mas, unsigned long *startp, + void *entry, unsigned long range_lo, unsigned long range_hi, + unsigned long *next, gfp_t gfp) +{ + unsigned long min = range_lo; + int ret = 0; + + range_lo = max(min, *next); + ret = mas_empty_area(mas, range_lo, range_hi, 1); + if ((mas->tree->ma_flags & MT_FLAGS_ALLOC_WRAPPED) && ret == 0) { + mas->tree->ma_flags &= ~MT_FLAGS_ALLOC_WRAPPED; + ret = 1; + } + if (ret < 0 && range_lo > min) { + ret = mas_empty_area(mas, min, range_hi, 1); + if (ret == 0) + ret = 1; + } + if (ret < 0) + return ret; + + do { + mas_insert(mas, entry); + } while (mas_nomem(mas, gfp)); + if (mas_is_err(mas)) + return xa_err(mas->node); + + *startp = mas->index; + *next = *startp + 1; + if (*next == 0) + mas->tree->ma_flags |= MT_FLAGS_ALLOC_WRAPPED; + + return ret; +} +EXPORT_SYMBOL(mas_alloc_cyclic); + static __always_inline void mas_rewalk(struct ma_state *mas, unsigned long index) { retry: @@ -6490,6 +6540,49 @@ int mtree_alloc_range(struct maple_tree *mt, unsigned long *startp, } EXPORT_SYMBOL(mtree_alloc_range); +/** + * mtree_alloc_cyclic() - Find somewhere to store this entry in the tree. + * @mt: The maple tree. + * @startp: Pointer to ID. + * @range_lo: Lower bound of range to search. + * @range_hi: Upper bound of range to search. + * @entry: The entry to store. + * @next: Pointer to next ID to allocate. + * @gfp: The GFP_FLAGS to use for allocations. + * + * Finds an empty entry in @mt after @next, stores the new index into + * the @id pointer, stores the entry at that index, then updates @next. + * + * @mt must be initialized with the MT_FLAGS_ALLOC_RANGE flag. + * + * Context: Any context. Takes and releases the mt.lock. May sleep if + * the @gfp flags permit. + * + * Return: 0 if the allocation succeeded without wrapping, 1 if the + * allocation succeeded after wrapping, -ENOMEM if memory could not be + * allocated, -EINVAL if @mt cannot be used, or -EBUSY if there are no + * free entries. + */ +int mtree_alloc_cyclic(struct maple_tree *mt, unsigned long *startp, + void *entry, unsigned long range_lo, unsigned long range_hi, + unsigned long *next, gfp_t gfp) +{ + int ret; + + MA_STATE(mas, mt, 0, 0); + + if (!mt_is_alloc(mt)) + return -EINVAL; + if (WARN_ON_ONCE(mt_is_reserved(entry))) + return -EINVAL; + mtree_lock(mt); + ret = mas_alloc_cyclic(&mas, startp, entry, range_lo, range_hi, + next, gfp); + mtree_unlock(mt); + return ret; +} +EXPORT_SYMBOL(mtree_alloc_cyclic); + int mtree_alloc_rrange(struct maple_tree *mt, unsigned long *startp, void *entry, unsigned long size, unsigned long min, unsigned long max, gfp_t gfp) -- 2.39.2
