From: Chuck Lever <chuck.lever@xxxxxxxxxx>
I need a cyclic allocator for the simple_offset implementation in
fs/libfs.c.
Signed-off-by: Chuck Lever <chuck.lever@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 6f241bb38799..af0970288727 100644
--- a/lib/maple_tree.c
+++ b/lib/maple_tree.c
@@ -4290,6 +4290,56 @@ 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:
@@ -6443,6 +6493,49 @@ 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)
