[PATCH 08/28] maple_tree.h: move declarations to maple_tree_types.h

Max Kellermann
2024-01-31T14:50:23Z

include/linux/maple_tree.h | 323 +----------------------------
include/linux/maple_tree_types.h | 341 +++++++++++++++++++++++++++++++
include/linux/mm.h | 1 +
include/linux/mm_types.h | 2 +-
4 files changed, 345 insertions(+), 322 deletions(-)
create mode 100644 include/linux/maple_tree_types.h

diff --git a/include/linux/maple_tree.h b/include/linux/maple_tree.h
index b3d63123b945..7f5dd33f4b94 100644
--- a/include/linux/maple_tree.h
+++ b/include/linux/maple_tree.h
@@ -8,147 +8,13 @@
* Matthew Wilcox <willy@infradead.org>
*/

+#include <linux/maple_tree_types.h>
+
#include <linux/kernel.h>
#include <linux/rcupdate.h>
#include <linux/spinlock.h>
/* #define CONFIG_MAPLE_RCU_DISABLED */

-/*
- * Allocated nodes are mutable until they have been inserted into the tree,
- * at which time they cannot change their type until they have been removed
- * from the tree and an RCU grace period has passed.
- *
- * Removed nodes have their ->parent set to point to themselves. RCU readers
- * check ->parent before relying on the value that they loaded from the
- * slots array. This lets us reuse the slots array for the RCU head.
- *
- * Nodes in the tree point to their parent unless bit 0 is set.
- */
-#if defined(CONFIG_64BIT) || defined(BUILD_VDSO32_64)
-/* 64bit sizes */
-#define MAPLE_NODE_SLOTS 31 /* 256 bytes including ->parent */
-#define MAPLE_RANGE64_SLOTS 16 /* 256 bytes */
-#define MAPLE_ARANGE64_SLOTS 10 /* 240 bytes */
-#define MAPLE_ALLOC_SLOTS (MAPLE_NODE_SLOTS - 1)
-#else
-/* 32bit sizes */
-#define MAPLE_NODE_SLOTS 63 /* 256 bytes including ->parent */
-#define MAPLE_RANGE64_SLOTS 32 /* 256 bytes */
-#define MAPLE_ARANGE64_SLOTS 21 /* 240 bytes */
-#define MAPLE_ALLOC_SLOTS (MAPLE_NODE_SLOTS - 2)
-#endif /* defined(CONFIG_64BIT) || defined(BUILD_VDSO32_64) */
-
-#define MAPLE_NODE_MASK 255UL
-
-/*
- * The node->parent of the root node has bit 0 set and the rest of the pointer
- * is a pointer to the tree itself. No more bits are available in this pointer
- * (on m68k, the data structure may only be 2-byte aligned).
- *
- * Internal non-root nodes can only have maple_range_* nodes as parents. The
- * parent pointer is 256B aligned like all other tree nodes. When storing a 32
- * or 64 bit values, the offset can fit into 4 bits. The 16 bit values need an
- * extra bit to store the offset. This extra bit comes from a reuse of the last
- * bit in the node type. This is possible by using bit 1 to indicate if bit 2
- * is part of the type or the slot.
- *
- * Once the type is decided, the decision of an allocation range type or a range
- * type is done by examining the immutable tree flag for the MAPLE_ALLOC_RANGE
- * flag.
- *
- * Node types:
- * 0x??1 = Root
- * 0x?00 = 16 bit nodes
- * 0x010 = 32 bit nodes
- * 0x110 = 64 bit nodes
- *
- * Slot size and location in the parent pointer:
- * type : slot location
- * 0x??1 : Root
- * 0x?00 : 16 bit values, type in 0-1, slot in 2-6
- * 0x010 : 32 bit values, type in 0-2, slot in 3-6
- * 0x110 : 64 bit values, type in 0-2, slot in 3-6
- */
-
-/*
- * This metadata is used to optimize the gap updating code and in reverse
- * searching for gaps or any other code that needs to find the end of the data.
- */
-struct maple_metadata {
- unsigned char end;
- unsigned char gap;
-};
-
-/*
- * Leaf nodes do not store pointers to nodes, they store user data. Users may
- * store almost any bit pattern. As noted above, the optimisation of storing an
- * entry at 0 in the root pointer cannot be done for data which have the bottom
- * two bits set to '10'. We also reserve values with the bottom two bits set to
- * '10' which are below 4096 (ie 2, 6, 10 .. 4094) for internal use. Some APIs
- * return errnos as a negative errno shifted right by two bits and the bottom
- * two bits set to '10', and while choosing to store these values in the array
- * is not an error, it may lead to confusion if you're testing for an error with
- * mas_is_err().
- *
- * Non-leaf nodes store the type of the node pointed to (enum maple_type in bits
- * 3-6), bit 2 is reserved. That leaves bits 0-1 unused for now.
- *
- * In regular B-Tree terms, pivots are called keys. The term pivot is used to
- * indicate that the tree is specifying ranges, Pivots may appear in the
- * subtree with an entry attached to the value whereas keys are unique to a
- * specific position of a B-tree. Pivot values are inclusive of the slot with
- * the same index.
- */
-
-struct maple_range_64 {
- struct maple_pnode *parent;
- unsigned long pivot[MAPLE_RANGE64_SLOTS - 1];
- union {
- void __rcu *slot[MAPLE_RANGE64_SLOTS];
- struct {
- void __rcu *pad[MAPLE_RANGE64_SLOTS - 1];
- struct maple_metadata meta;
- };
- };
-};
-
-/*
- * At tree creation time, the user can specify that they're willing to trade off
- * storing fewer entries in a tree in return for storing more information in
- * each node.
- *
- * The maple tree supports recording the largest range of NULL entries available
- * in this node, also called gaps. This optimises the tree for allocating a
- * range.
- */
-struct maple_arange_64 {
- struct maple_pnode *parent;
- unsigned long pivot[MAPLE_ARANGE64_SLOTS - 1];
- void __rcu *slot[MAPLE_ARANGE64_SLOTS];
- unsigned long gap[MAPLE_ARANGE64_SLOTS];
- struct maple_metadata meta;
-};
-
-struct maple_alloc {
- unsigned long total;
- unsigned char node_count;
- unsigned int request_count;
- struct maple_alloc *slot[MAPLE_ALLOC_SLOTS];
-};
-
-struct maple_topiary {
- struct maple_pnode *parent;
- struct maple_enode *next; /* Overlaps the pivot */
-};
-
-enum maple_type {
- maple_dense,
- maple_leaf_64,
- maple_range_64,
- maple_arange_64,
-};
-
-
/**
* DOC: Maple tree flags
*
@@ -181,7 +47,6 @@ enum maple_type {
#define MAPLE_RESERVED_RANGE 4096

#ifdef CONFIG_LOCKDEP
-typedef struct lockdep_map *lockdep_map_p;
#define mt_lock_is_held(mt) \
(!(mt)->ma_external_lock || lock_is_held((mt)->ma_external_lock))

@@ -194,36 +59,12 @@ typedef struct lockdep_map *lockdep_map_p;

#define mt_on_stack(mt) (mt).ma_external_lock = NULL
#else
-typedef struct { /* nothing */ } lockdep_map_p;
#define mt_lock_is_held(mt) 1
#define mt_write_lock_is_held(mt) 1
#define mt_set_external_lock(mt, lock) do { } while (0)
#define mt_on_stack(mt) do { } while (0)
#endif

-/*
- * If the tree contains a single entry at index 0, it is usually stored in
- * tree->ma_root. To optimise for the page cache, an entry which ends in '00',
- * '01' or '11' is stored in the root, but an entry which ends in '10' will be
- * stored in a node. Bits 3-6 are used to store enum maple_type.
- *
- * The flags are used both to store some immutable information about this tree
- * (set at tree creation time) and dynamic information set under the spinlock.
- *
- * Another use of flags are to indicate global states of the tree. This is the
- * case with the MAPLE_USE_RCU flag, which indicates the tree is currently in
- * RCU mode. This mode was added to allow the tree to reuse nodes instead of
- * re-allocating and RCU freeing nodes when there is a single user.
- */
-struct maple_tree {
- union {
- spinlock_t ma_lock;
- lockdep_map_p ma_external_lock;
- };
- unsigned int ma_flags;
- void __rcu *ma_root;
-};
-
/**
* MTREE_INIT() - Initialize a maple tree
* @name: The maple tree name
@@ -260,56 +101,6 @@ struct maple_tree {
spin_lock_nested((&(mt)->ma_lock), subclass)
#define mtree_unlock(mt) spin_unlock((&(mt)->ma_lock))

-/*
- * The Maple Tree squeezes various bits in at various points which aren't
- * necessarily obvious. Usually, this is done by observing that pointers are
- * N-byte aligned and thus the bottom log_2(N) bits are available for use. We
- * don't use the high bits of pointers to store additional information because
- * we don't know what bits are unused on any given architecture.
- *
- * Nodes are 256 bytes in size and are also aligned to 256 bytes, giving us 8
- * low bits for our own purposes. Nodes are currently of 4 types:
- * 1. Single pointer (Range is 0-0)
- * 2. Non-leaf Allocation Range nodes
- * 3. Non-leaf Range nodes
- * 4. Leaf Range nodes All nodes consist of a number of node slots,
- * pivots, and a parent pointer.
- */
-
-struct maple_node {
- union {
- struct {
- struct maple_pnode *parent;
- void __rcu *slot[MAPLE_NODE_SLOTS];
- };
- struct {
- void *pad;
- struct rcu_head rcu;
- struct maple_enode *piv_parent;
- unsigned char parent_slot;
- enum maple_type type;
- unsigned char slot_len;
- unsigned int ma_flags;
- };
- struct maple_range_64 mr64;
- struct maple_arange_64 ma64;
- struct maple_alloc alloc;
- };
-};
-
-/*
- * More complicated stores can cause two nodes to become one or three and
- * potentially alter the height of the tree. Either half of the tree may need
- * to be rebalanced against the other. The ma_topiary struct is used to track
- * which nodes have been 'cut' from the tree so that the change can be done
- * safely at a later date. This is done to support RCU.
- */
-struct ma_topiary {
- struct maple_enode *head;
- struct maple_enode *tail;
- struct maple_tree *mtree;
-};
-
void *mtree_load(struct maple_tree *mt, unsigned long index);

int mtree_insert(struct maple_tree *mt, unsigned long index,
@@ -349,105 +140,6 @@ static inline bool mtree_empty(const struct maple_tree *mt)

/* Advanced API */

-/*
- * Maple State Status
- * ma_active means the maple state is pointing to a node and offset and can
- * continue operating on the tree.
- * ma_start means we have not searched the tree.
- * ma_root means we have searched the tree and the entry we found lives in
- * the root of the tree (ie it has index 0, length 1 and is the only entry in
- * the tree).
- * ma_none means we have searched the tree and there is no node in the
- * tree for this entry. For example, we searched for index 1 in an empty
- * tree. Or we have a tree which points to a full leaf node and we
- * searched for an entry which is larger than can be contained in that
- * leaf node.
- * ma_pause means the data within the maple state may be stale, restart the
- * operation
- * ma_overflow means the search has reached the upper limit of the search
- * ma_underflow means the search has reached the lower limit of the search
- * ma_error means there was an error, check the node for the error number.
- */
-enum maple_status {
- ma_active,
- ma_start,
- ma_root,
- ma_none,
- ma_pause,
- ma_overflow,
- ma_underflow,
- ma_error,
-};
-
-/*
- * The maple state is defined in the struct ma_state and is used to keep track
- * of information during operations, and even between operations when using the
- * advanced API.
- *
- * If state->node has bit 0 set then it references a tree location which is not
- * a node (eg the root). If bit 1 is set, the rest of the bits are a negative
- * errno. Bit 2 (the 'unallocated slots' bit) is clear. Bits 3-6 indicate the
- * node type.
- *
- * state->alloc either has a request number of nodes or an allocated node. If
- * stat->alloc has a requested number of nodes, the first bit will be set (0x1)
- * and the remaining bits are the value. If state->alloc is a node, then the
- * node will be of type maple_alloc. maple_alloc has MAPLE_NODE_SLOTS - 1 for
- * storing more allocated nodes, a total number of nodes allocated, and the
- * node_count in this node. node_count is the number of allocated nodes in this
- * node. The scaling beyond MAPLE_NODE_SLOTS - 1 is handled by storing further
- * nodes into state->alloc->slot[0]'s node. Nodes are taken from state->alloc
- * by removing a node from the state->alloc node until state->alloc->node_count
- * is 1, when state->alloc is returned and the state->alloc->slot[0] is promoted
- * to state->alloc. Nodes are pushed onto state->alloc by putting the current
- * state->alloc into the pushed node's slot[0].
- *
- * The state also contains the implied min/max of the state->node, the depth of
- * this search, and the offset. The implied min/max are either from the parent
- * node or are 0-oo for the root node. The depth is incremented or decremented
- * every time a node is walked down or up. The offset is the slot/pivot of
- * interest in the node - either for reading or writing.
- *
- * When returning a value the maple state index and last respectively contain
- * the start and end of the range for the entry. Ranges are inclusive in the
- * Maple Tree.
- *
- * The status of the state is used to determine how the next action should treat
- * the state. For instance, if the status is ma_start then the next action
- * should start at the root of the tree and walk down. If the status is
- * ma_pause then the node may be stale data and should be discarded. If the
- * status is ma_overflow, then the last action hit the upper limit.
- *
- */
-struct ma_state {
- struct maple_tree *tree; /* The tree we're operating in */
- unsigned long index; /* The index we're operating on - range start */
- unsigned long last; /* The last index we're operating on - range end */
- struct maple_enode *node; /* The node containing this entry */
- unsigned long min; /* The minimum index of this node - implied pivot min */
- unsigned long max; /* The maximum index of this node - implied pivot max */
- struct maple_alloc *alloc; /* Allocated nodes for this operation */
- enum maple_status status; /* The status of the state (active, start, none, etc) */
- unsigned char depth; /* depth of tree descent during write */
- unsigned char offset;
- unsigned char mas_flags;
- unsigned char end; /* The end of the node */
-};
-
-struct ma_wr_state {
- struct ma_state *mas;
- struct maple_node *node; /* Decoded mas->node */
- unsigned long r_min; /* range min */
- unsigned long r_max; /* range max */
- enum maple_type type; /* mas->node type */
- unsigned char offset_end; /* The offset where the write ends */
- unsigned long *pivots; /* mas->node->pivots pointer */
- unsigned long end_piv; /* The pivot at the offset end */
- void __rcu **slots; /* mas->node->slots pointer */
- void *entry; /* The entry to write */
- void *content; /* The existing entry that is being overwritten */
-};
-
#define mas_lock(mas) spin_lock(&((mas)->tree->ma_lock))
#define mas_lock_nested(mas, subclass) \
spin_lock_nested(&((mas)->tree->ma_lock), subclass)
@@ -520,17 +212,6 @@ int mas_empty_area(struct ma_state *mas, unsigned long min, unsigned long max,
int mas_empty_area_rev(struct ma_state *mas, unsigned long min,
unsigned long max, unsigned long size);

-static inline void mas_init(struct ma_state *mas, struct maple_tree *tree,
- unsigned long addr)
-{
- memset(mas, 0, sizeof(struct ma_state));
- mas->tree = tree;
- mas->index = mas->last = addr;
- mas->max = ULONG_MAX;
- mas->status = ma_start;
- mas->node = NULL;
-}
-
static inline bool mas_is_active(struct ma_state *mas)
{
return mas->status == ma_active;
diff --git a/include/linux/maple_tree_types.h b/include/linux/maple_tree_types.h
new file mode 100644
index 000000000000..fe13414f239d
--- /dev/null
+++ b/include/linux/maple_tree_types.h
@@ -0,0 +1,341 @@
+/* SPDX-License-Identifier: GPL-2.0+ */
+#ifndef _LINUX_MAPLE_TREE_TYPES_H
+#define _LINUX_MAPLE_TREE_TYPES_H
+/*
+ * Maple Tree - An RCU-safe adaptive tree for storing ranges
+ * Copyright (c) 2018-2022 Oracle
+ * Authors: Liam R. Howlett <Liam.Howlett@Oracle.com>
+ * Matthew Wilcox <willy@infradead.org>
+ */
+
+#include <linux/spinlock_types.h>
+#include <linux/string.h> // for memset()
+#include <linux/limits.h> // for ULONG_MAX
+
+/*
+ * Allocated nodes are mutable until they have been inserted into the tree,
+ * at which time they cannot change their type until they have been removed
+ * from the tree and an RCU grace period has passed.
+ *
+ * Removed nodes have their ->parent set to point to themselves. RCU readers
+ * check ->parent before relying on the value that they loaded from the
+ * slots array. This lets us reuse the slots array for the RCU head.
+ *
+ * Nodes in the tree point to their parent unless bit 0 is set.
+ */
+#if defined(CONFIG_64BIT) || defined(BUILD_VDSO32_64)
+/* 64bit sizes */
+#define MAPLE_NODE_SLOTS 31 /* 256 bytes including ->parent */
+#define MAPLE_RANGE64_SLOTS 16 /* 256 bytes */
+#define MAPLE_ARANGE64_SLOTS 10 /* 240 bytes */
+#define MAPLE_ALLOC_SLOTS (MAPLE_NODE_SLOTS - 1)
+#else
+/* 32bit sizes */
+#define MAPLE_NODE_SLOTS 63 /* 256 bytes including ->parent */
+#define MAPLE_RANGE64_SLOTS 32 /* 256 bytes */
+#define MAPLE_ARANGE64_SLOTS 21 /* 240 bytes */
+#define MAPLE_ALLOC_SLOTS (MAPLE_NODE_SLOTS - 2)
+#endif /* defined(CONFIG_64BIT) || defined(BUILD_VDSO32_64) */
+
+#define MAPLE_NODE_MASK 255UL
+
+/*
+ * The node->parent of the root node has bit 0 set and the rest of the pointer
+ * is a pointer to the tree itself. No more bits are available in this pointer
+ * (on m68k, the data structure may only be 2-byte aligned).
+ *
+ * Internal non-root nodes can only have maple_range_* nodes as parents. The
+ * parent pointer is 256B aligned like all other tree nodes. When storing a 32
+ * or 64 bit values, the offset can fit into 4 bits. The 16 bit values need an
+ * extra bit to store the offset. This extra bit comes from a reuse of the last
+ * bit in the node type. This is possible by using bit 1 to indicate if bit 2
+ * is part of the type or the slot.
+ *
+ * Once the type is decided, the decision of an allocation range type or a range
+ * type is done by examining the immutable tree flag for the MAPLE_ALLOC_RANGE
+ * flag.
+ *
+ * Node types:
+ * 0x??1 = Root
+ * 0x?00 = 16 bit nodes
+ * 0x010 = 32 bit nodes
+ * 0x110 = 64 bit nodes
+ *
+ * Slot size and location in the parent pointer:
+ * type : slot location
+ * 0x??1 : Root
+ * 0x?00 : 16 bit values, type in 0-1, slot in 2-6
+ * 0x010 : 32 bit values, type in 0-2, slot in 3-6
+ * 0x110 : 64 bit values, type in 0-2, slot in 3-6
+ */
+
+/*
+ * This metadata is used to optimize the gap updating code and in reverse
+ * searching for gaps or any other code that needs to find the end of the data.
+ */
+struct maple_metadata {
+ unsigned char end;
+ unsigned char gap;
+};
+
+/*
+ * Leaf nodes do not store pointers to nodes, they store user data. Users may
+ * store almost any bit pattern. As noted above, the optimisation of storing an
+ * entry at 0 in the root pointer cannot be done for data which have the bottom
+ * two bits set to '10'. We also reserve values with the bottom two bits set to
+ * '10' which are below 4096 (ie 2, 6, 10 .. 4094) for internal use. Some APIs
+ * return errnos as a negative errno shifted right by two bits and the bottom
+ * two bits set to '10', and while choosing to store these values in the array
+ * is not an error, it may lead to confusion if you're testing for an error with
+ * mas_is_err().
+ *
+ * Non-leaf nodes store the type of the node pointed to (enum maple_type in bits
+ * 3-6), bit 2 is reserved. That leaves bits 0-1 unused for now.
+ *
+ * In regular B-Tree terms, pivots are called keys. The term pivot is used to
+ * indicate that the tree is specifying ranges, Pivots may appear in the
+ * subtree with an entry attached to the value whereas keys are unique to a
+ * specific position of a B-tree. Pivot values are inclusive of the slot with
+ * the same index.
+ */
+
+struct maple_range_64 {
+ struct maple_pnode *parent;
+ unsigned long pivot[MAPLE_RANGE64_SLOTS - 1];
+ union {
+ void __rcu *slot[MAPLE_RANGE64_SLOTS];
+ struct {
+ void __rcu *pad[MAPLE_RANGE64_SLOTS - 1];
+ struct maple_metadata meta;
+ };
+ };
+};
+
+/*
+ * At tree creation time, the user can specify that they're willing to trade off
+ * storing fewer entries in a tree in return for storing more information in
+ * each node.
+ *
+ * The maple tree supports recording the largest range of NULL entries available
+ * in this node, also called gaps. This optimises the tree for allocating a
+ * range.
+ */
+struct maple_arange_64 {
+ struct maple_pnode *parent;
+ unsigned long pivot[MAPLE_ARANGE64_SLOTS - 1];
+ void __rcu *slot[MAPLE_ARANGE64_SLOTS];
+ unsigned long gap[MAPLE_ARANGE64_SLOTS];
+ struct maple_metadata meta;
+};
+
+struct maple_alloc {
+ unsigned long total;
+ unsigned char node_count;
+ unsigned int request_count;
+ struct maple_alloc *slot[MAPLE_ALLOC_SLOTS];
+};
+
+struct maple_topiary {
+ struct maple_pnode *parent;
+ struct maple_enode *next; /* Overlaps the pivot */
+};
+
+enum maple_type {
+ maple_dense,
+ maple_leaf_64,
+ maple_range_64,
+ maple_arange_64,
+};
+
+#ifdef CONFIG_LOCKDEP
+typedef struct lockdep_map *lockdep_map_p;
+#else
+typedef struct { /* nothing */ } lockdep_map_p;
+#endif
+
+/*
+ * If the tree contains a single entry at index 0, it is usually stored in
+ * tree->ma_root. To optimise for the page cache, an entry which ends in '00',
+ * '01' or '11' is stored in the root, but an entry which ends in '10' will be
+ * stored in a node. Bits 3-6 are used to store enum maple_type.
+ *
+ * The flags are used both to store some immutable information about this tree
+ * (set at tree creation time) and dynamic information set under the spinlock.
+ *
+ * Another use of flags are to indicate global states of the tree. This is the
+ * case with the MAPLE_USE_RCU flag, which indicates the tree is currently in
+ * RCU mode. This mode was added to allow the tree to reuse nodes instead of
+ * re-allocating and RCU freeing nodes when there is a single user.
+ */
+struct maple_tree {
+ union {
+ spinlock_t ma_lock;
+ lockdep_map_p ma_external_lock;
+ };
+ unsigned int ma_flags;
+ void __rcu *ma_root;
+};
+
+/*
+ * The Maple Tree squeezes various bits in at various points which aren't
+ * necessarily obvious. Usually, this is done by observing that pointers are
+ * N-byte aligned and thus the bottom log_2(N) bits are available for use. We
+ * don't use the high bits of pointers to store additional information because
+ * we don't know what bits are unused on any given architecture.
+ *
+ * Nodes are 256 bytes in size and are also aligned to 256 bytes, giving us 8
+ * low bits for our own purposes. Nodes are currently of 4 types:
+ * 1. Single pointer (Range is 0-0)
+ * 2. Non-leaf Allocation Range nodes
+ * 3. Non-leaf Range nodes
+ * 4. Leaf Range nodes All nodes consist of a number of node slots,
+ * pivots, and a parent pointer.
+ */
+
+struct maple_node {
+ union {
+ struct {
+ struct maple_pnode *parent;
+ void __rcu *slot[MAPLE_NODE_SLOTS];
+ };
+ struct {
+ void *pad;
+ struct rcu_head rcu;
+ struct maple_enode *piv_parent;
+ unsigned char parent_slot;
+ enum maple_type type;
+ unsigned char slot_len;
+ unsigned int ma_flags;
+ };
+ struct maple_range_64 mr64;
+ struct maple_arange_64 ma64;
+ struct maple_alloc alloc;
+ };
+};
+
+/*
+ * More complicated stores can cause two nodes to become one or three and
+ * potentially alter the height of the tree. Either half of the tree may need
+ * to be rebalanced against the other. The ma_topiary struct is used to track
+ * which nodes have been 'cut' from the tree so that the change can be done
+ * safely at a later date. This is done to support RCU.
+ */
+struct ma_topiary {
+ struct maple_enode *head;
+ struct maple_enode *tail;
+ struct maple_tree *mtree;
+};
+
+/* Advanced API */
+
+/*
+ * Maple State Status
+ * ma_active means the maple state is pointing to a node and offset and can
+ * continue operating on the tree.
+ * ma_start means we have not searched the tree.
+ * ma_root means we have searched the tree and the entry we found lives in
+ * the root of the tree (ie it has index 0, length 1 and is the only entry in
+ * the tree).
+ * ma_none means we have searched the tree and there is no node in the
+ * tree for this entry. For example, we searched for index 1 in an empty
+ * tree. Or we have a tree which points to a full leaf node and we
+ * searched for an entry which is larger than can be contained in that
+ * leaf node.
+ * ma_pause means the data within the maple state may be stale, restart the
+ * operation
+ * ma_overflow means the search has reached the upper limit of the search
+ * ma_underflow means the search has reached the lower limit of the search
+ * ma_error means there was an error, check the node for the error number.
+ */
+enum maple_status {
+ ma_active,
+ ma_start,
+ ma_root,
+ ma_none,
+ ma_pause,
+ ma_overflow,
+ ma_underflow,
+ ma_error,
+};
+
+/*
+ * The maple state is defined in the struct ma_state and is used to keep track
+ * of information during operations, and even between operations when using the
+ * advanced API.
+ *
+ * If state->node has bit 0 set then it references a tree location which is not
+ * a node (eg the root). If bit 1 is set, the rest of the bits are a negative
+ * errno. Bit 2 (the 'unallocated slots' bit) is clear. Bits 3-6 indicate the
+ * node type.
+ *
+ * state->alloc either has a request number of nodes or an allocated node. If
+ * stat->alloc has a requested number of nodes, the first bit will be set (0x1)
+ * and the remaining bits are the value. If state->alloc is a node, then the
+ * node will be of type maple_alloc. maple_alloc has MAPLE_NODE_SLOTS - 1 for
+ * storing more allocated nodes, a total number of nodes allocated, and the
+ * node_count in this node. node_count is the number of allocated nodes in this
+ * node. The scaling beyond MAPLE_NODE_SLOTS - 1 is handled by storing further
+ * nodes into state->alloc->slot[0]'s node. Nodes are taken from state->alloc
+ * by removing a node from the state->alloc node until state->alloc->node_count
+ * is 1, when state->alloc is returned and the state->alloc->slot[0] is promoted
+ * to state->alloc. Nodes are pushed onto state->alloc by putting the current
+ * state->alloc into the pushed node's slot[0].
+ *
+ * The state also contains the implied min/max of the state->node, the depth of
+ * this search, and the offset. The implied min/max are either from the parent
+ * node or are 0-oo for the root node. The depth is incremented or decremented
+ * every time a node is walked down or up. The offset is the slot/pivot of
+ * interest in the node - either for reading or writing.
+ *
+ * When returning a value the maple state index and last respectively contain
+ * the start and end of the range for the entry. Ranges are inclusive in the
+ * Maple Tree.
+ *
+ * The status of the state is used to determine how the next action should treat
+ * the state. For instance, if the status is ma_start then the next action
+ * should start at the root of the tree and walk down. If the status is
+ * ma_pause then the node may be stale data and should be discarded. If the
+ * status is ma_overflow, then the last action hit the upper limit.
+ *
+ */
+struct ma_state {
+ struct maple_tree *tree; /* The tree we're operating in */
+ unsigned long index; /* The index we're operating on - range start */
+ unsigned long last; /* The last index we're operating on - range end */
+ struct maple_enode *node; /* The node containing this entry */
+ unsigned long min; /* The minimum index of this node - implied pivot min */
+ unsigned long max; /* The maximum index of this node - implied pivot max */
+ struct maple_alloc *alloc; /* Allocated nodes for this operation */
+ enum maple_status status; /* The status of the state (active, start, none, etc) */
+ unsigned char depth; /* depth of tree descent during write */
+ unsigned char offset;
+ unsigned char mas_flags;
+ unsigned char end; /* The end of the node */
+};
+
+struct ma_wr_state {
+ struct ma_state *mas;
+ struct maple_node *node; /* Decoded mas->node */
+ unsigned long r_min; /* range min */
+ unsigned long r_max; /* range max */
+ enum maple_type type; /* mas->node type */
+ unsigned char offset_end; /* The offset where the write ends */
+ unsigned long *pivots; /* mas->node->pivots pointer */
+ unsigned long end_piv; /* The pivot at the offset end */
+ void __rcu **slots; /* mas->node->slots pointer */
+ void *entry; /* The entry to write */
+ void *content; /* The existing entry that is being overwritten */
+};
+
+static inline void mas_init(struct ma_state *mas, struct maple_tree *tree,
+ unsigned long addr)
+{
+ memset(mas, 0, sizeof(struct ma_state));
+ mas->tree = tree;
+ mas->index = mas->last = addr;
+ mas->max = ULONG_MAX;
+ mas->status = ma_start;
+ mas->node = NULL;
+}
+
+#endif /*_LINUX_MAPLE_TREE_TYPES_H */
diff --git a/include/linux/mm.h b/include/linux/mm.h
index 9338b6217e3c..68910777dd1c 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -13,6 +13,7 @@
#include <linux/debug_locks.h>
#include <linux/mm_types.h>
#include <linux/mmap_lock.h>
+#include <linux/maple_tree.h>
#include <linux/range.h>
#include <linux/pfn.h>
#include <linux/bit_spinlock.h>
diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h
index 28856bc6fdde..122a9011985b 100644
--- a/include/linux/mm_types.h
+++ b/include/linux/mm_types.h
@@ -9,7 +9,7 @@
#include <linux/list.h>
#include <linux/spinlock_types.h>
#include <linux/rbtree_types.h>
-#include <linux/maple_tree.h>
+#include <linux/maple_tree_types.h>
#include <linux/rwsem.h>
#include <linux/cpumask.h>
#include <linux/uprobes.h>
--
2.39.2