698 lines
23 KiB
C
698 lines
23 KiB
C
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/* SPDX-License-Identifier: GPL-2.0+ */
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#ifndef _LINUX_MAPLE_TREE_H
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#define _LINUX_MAPLE_TREE_H
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/*
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* Maple Tree - An RCU-safe adaptive tree for storing ranges
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* Copyright (c) 2018-2022 Oracle
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* Authors: Liam R. Howlett <Liam.Howlett@Oracle.com>
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* Matthew Wilcox <willy@infradead.org>
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*/
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#include <linux/kernel.h>
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#include <linux/rcupdate.h>
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#include <linux/spinlock.h>
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/* #define CONFIG_MAPLE_RCU_DISABLED */
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/*
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* Allocated nodes are mutable until they have been inserted into the tree,
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* at which time they cannot change their type until they have been removed
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* from the tree and an RCU grace period has passed.
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*
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* Removed nodes have their ->parent set to point to themselves. RCU readers
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* check ->parent before relying on the value that they loaded from the
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* slots array. This lets us reuse the slots array for the RCU head.
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*
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* Nodes in the tree point to their parent unless bit 0 is set.
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*/
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#if defined(CONFIG_64BIT) || defined(BUILD_VDSO32_64)
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/* 64bit sizes */
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#define MAPLE_NODE_SLOTS 31 /* 256 bytes including ->parent */
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#define MAPLE_RANGE64_SLOTS 16 /* 256 bytes */
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#define MAPLE_ARANGE64_SLOTS 10 /* 240 bytes */
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#define MAPLE_ARANGE64_META_MAX 15 /* Out of range for metadata */
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#define MAPLE_ALLOC_SLOTS (MAPLE_NODE_SLOTS - 1)
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#else
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/* 32bit sizes */
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#define MAPLE_NODE_SLOTS 63 /* 256 bytes including ->parent */
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#define MAPLE_RANGE64_SLOTS 32 /* 256 bytes */
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#define MAPLE_ARANGE64_SLOTS 21 /* 240 bytes */
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#define MAPLE_ARANGE64_META_MAX 31 /* Out of range for metadata */
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#define MAPLE_ALLOC_SLOTS (MAPLE_NODE_SLOTS - 2)
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#endif /* defined(CONFIG_64BIT) || defined(BUILD_VDSO32_64) */
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#define MAPLE_NODE_MASK 255UL
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/*
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* The node->parent of the root node has bit 0 set and the rest of the pointer
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* is a pointer to the tree itself. No more bits are available in this pointer
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* (on m68k, the data structure may only be 2-byte aligned).
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*
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* Internal non-root nodes can only have maple_range_* nodes as parents. The
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* parent pointer is 256B aligned like all other tree nodes. When storing a 32
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* or 64 bit values, the offset can fit into 4 bits. The 16 bit values need an
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* extra bit to store the offset. This extra bit comes from a reuse of the last
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* bit in the node type. This is possible by using bit 1 to indicate if bit 2
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* is part of the type or the slot.
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*
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* Once the type is decided, the decision of an allocation range type or a range
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* type is done by examining the immutable tree flag for the MAPLE_ALLOC_RANGE
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* flag.
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*
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* Node types:
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* 0x??1 = Root
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* 0x?00 = 16 bit nodes
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* 0x010 = 32 bit nodes
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* 0x110 = 64 bit nodes
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*
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* Slot size and location in the parent pointer:
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* type : slot location
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* 0x??1 : Root
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* 0x?00 : 16 bit values, type in 0-1, slot in 2-6
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* 0x010 : 32 bit values, type in 0-2, slot in 3-6
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* 0x110 : 64 bit values, type in 0-2, slot in 3-6
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*/
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/*
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* This metadata is used to optimize the gap updating code and in reverse
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* searching for gaps or any other code that needs to find the end of the data.
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*/
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struct maple_metadata {
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unsigned char end;
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unsigned char gap;
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};
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/*
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* Leaf nodes do not store pointers to nodes, they store user data. Users may
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* store almost any bit pattern. As noted above, the optimisation of storing an
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* entry at 0 in the root pointer cannot be done for data which have the bottom
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* two bits set to '10'. We also reserve values with the bottom two bits set to
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* '10' which are below 4096 (ie 2, 6, 10 .. 4094) for internal use. Some APIs
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* return errnos as a negative errno shifted right by two bits and the bottom
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* two bits set to '10', and while choosing to store these values in the array
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* is not an error, it may lead to confusion if you're testing for an error with
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* mas_is_err().
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*
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* Non-leaf nodes store the type of the node pointed to (enum maple_type in bits
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* 3-6), bit 2 is reserved. That leaves bits 0-1 unused for now.
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*
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* In regular B-Tree terms, pivots are called keys. The term pivot is used to
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* indicate that the tree is specifying ranges, Pivots may appear in the
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* subtree with an entry attached to the value whereas keys are unique to a
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* specific position of a B-tree. Pivot values are inclusive of the slot with
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* the same index.
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*/
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struct maple_range_64 {
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struct maple_pnode *parent;
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unsigned long pivot[MAPLE_RANGE64_SLOTS - 1];
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union {
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void __rcu *slot[MAPLE_RANGE64_SLOTS];
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struct {
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void __rcu *pad[MAPLE_RANGE64_SLOTS - 1];
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struct maple_metadata meta;
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};
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};
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};
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/*
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* At tree creation time, the user can specify that they're willing to trade off
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* storing fewer entries in a tree in return for storing more information in
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* each node.
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*
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* The maple tree supports recording the largest range of NULL entries available
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* in this node, also called gaps. This optimises the tree for allocating a
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* range.
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*/
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struct maple_arange_64 {
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struct maple_pnode *parent;
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unsigned long pivot[MAPLE_ARANGE64_SLOTS - 1];
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void __rcu *slot[MAPLE_ARANGE64_SLOTS];
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unsigned long gap[MAPLE_ARANGE64_SLOTS];
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struct maple_metadata meta;
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};
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struct maple_alloc {
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unsigned long total;
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unsigned char node_count;
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unsigned int request_count;
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struct maple_alloc *slot[MAPLE_ALLOC_SLOTS];
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};
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struct maple_topiary {
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struct maple_pnode *parent;
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struct maple_enode *next; /* Overlaps the pivot */
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};
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enum maple_type {
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maple_dense,
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maple_leaf_64,
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maple_range_64,
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maple_arange_64,
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};
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/**
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* DOC: Maple tree flags
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*
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* * MT_FLAGS_ALLOC_RANGE - Track gaps in this tree
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* * MT_FLAGS_USE_RCU - Operate in RCU mode
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* * MT_FLAGS_HEIGHT_OFFSET - The position of the tree height in the flags
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* * MT_FLAGS_HEIGHT_MASK - The mask for the maple tree height value
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* * MT_FLAGS_LOCK_MASK - How the mt_lock is used
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* * MT_FLAGS_LOCK_IRQ - Acquired irq-safe
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* * MT_FLAGS_LOCK_BH - Acquired bh-safe
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* * MT_FLAGS_LOCK_EXTERN - mt_lock is not used
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*
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* MAPLE_HEIGHT_MAX The largest height that can be stored
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*/
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#define MT_FLAGS_ALLOC_RANGE 0x01
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#define MT_FLAGS_USE_RCU 0x02
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#define MT_FLAGS_HEIGHT_OFFSET 0x02
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#define MT_FLAGS_HEIGHT_MASK 0x7C
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#define MT_FLAGS_LOCK_MASK 0x300
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#define MT_FLAGS_LOCK_IRQ 0x100
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#define MT_FLAGS_LOCK_BH 0x200
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#define MT_FLAGS_LOCK_EXTERN 0x300
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#define MAPLE_HEIGHT_MAX 31
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#define MAPLE_NODE_TYPE_MASK 0x0F
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#define MAPLE_NODE_TYPE_SHIFT 0x03
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#define MAPLE_RESERVED_RANGE 4096
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#ifdef CONFIG_LOCKDEP
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typedef struct lockdep_map *lockdep_map_p;
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#define mt_lock_is_held(mt) lock_is_held(mt->ma_external_lock)
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#define mt_set_external_lock(mt, lock) \
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(mt)->ma_external_lock = &(lock)->dep_map
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#else
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typedef struct { /* nothing */ } lockdep_map_p;
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#define mt_lock_is_held(mt) 1
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#define mt_set_external_lock(mt, lock) do { } while (0)
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#endif
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/*
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* If the tree contains a single entry at index 0, it is usually stored in
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* tree->ma_root. To optimise for the page cache, an entry which ends in '00',
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* '01' or '11' is stored in the root, but an entry which ends in '10' will be
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* stored in a node. Bits 3-6 are used to store enum maple_type.
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*
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* The flags are used both to store some immutable information about this tree
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* (set at tree creation time) and dynamic information set under the spinlock.
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*
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* Another use of flags are to indicate global states of the tree. This is the
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* case with the MAPLE_USE_RCU flag, which indicates the tree is currently in
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* RCU mode. This mode was added to allow the tree to reuse nodes instead of
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* re-allocating and RCU freeing nodes when there is a single user.
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*/
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struct maple_tree {
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union {
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spinlock_t ma_lock;
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lockdep_map_p ma_external_lock;
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};
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void __rcu *ma_root;
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unsigned int ma_flags;
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};
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/**
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* MTREE_INIT() - Initialize a maple tree
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* @name: The maple tree name
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* @__flags: The maple tree flags
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*
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*/
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#define MTREE_INIT(name, __flags) { \
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.ma_lock = __SPIN_LOCK_UNLOCKED((name).ma_lock), \
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.ma_flags = __flags, \
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.ma_root = NULL, \
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}
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/**
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* MTREE_INIT_EXT() - Initialize a maple tree with an external lock.
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* @name: The tree name
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* @__flags: The maple tree flags
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* @__lock: The external lock
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*/
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#ifdef CONFIG_LOCKDEP
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#define MTREE_INIT_EXT(name, __flags, __lock) { \
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.ma_external_lock = &(__lock).dep_map, \
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.ma_flags = (__flags), \
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.ma_root = NULL, \
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}
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#else
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#define MTREE_INIT_EXT(name, __flags, __lock) MTREE_INIT(name, __flags)
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#endif
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#define DEFINE_MTREE(name) \
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struct maple_tree name = MTREE_INIT(name, 0)
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#define mtree_lock(mt) spin_lock((&(mt)->ma_lock))
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#define mtree_unlock(mt) spin_unlock((&(mt)->ma_lock))
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/*
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* The Maple Tree squeezes various bits in at various points which aren't
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* necessarily obvious. Usually, this is done by observing that pointers are
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* N-byte aligned and thus the bottom log_2(N) bits are available for use. We
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* don't use the high bits of pointers to store additional information because
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* we don't know what bits are unused on any given architecture.
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*
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* Nodes are 256 bytes in size and are also aligned to 256 bytes, giving us 8
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* low bits for our own purposes. Nodes are currently of 4 types:
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* 1. Single pointer (Range is 0-0)
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* 2. Non-leaf Allocation Range nodes
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* 3. Non-leaf Range nodes
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* 4. Leaf Range nodes All nodes consist of a number of node slots,
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* pivots, and a parent pointer.
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*/
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struct maple_node {
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union {
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struct {
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struct maple_pnode *parent;
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void __rcu *slot[MAPLE_NODE_SLOTS];
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};
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struct {
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void *pad;
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struct rcu_head rcu;
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struct maple_enode *piv_parent;
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unsigned char parent_slot;
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enum maple_type type;
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unsigned char slot_len;
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unsigned int ma_flags;
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};
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struct maple_range_64 mr64;
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struct maple_arange_64 ma64;
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struct maple_alloc alloc;
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};
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};
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/*
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* More complicated stores can cause two nodes to become one or three and
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* potentially alter the height of the tree. Either half of the tree may need
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* to be rebalanced against the other. The ma_topiary struct is used to track
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* which nodes have been 'cut' from the tree so that the change can be done
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* safely at a later date. This is done to support RCU.
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*/
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struct ma_topiary {
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struct maple_enode *head;
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struct maple_enode *tail;
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struct maple_tree *mtree;
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};
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void *mtree_load(struct maple_tree *mt, unsigned long index);
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int mtree_insert(struct maple_tree *mt, unsigned long index,
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void *entry, gfp_t gfp);
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int mtree_insert_range(struct maple_tree *mt, unsigned long first,
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unsigned long last, void *entry, gfp_t gfp);
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int mtree_alloc_range(struct maple_tree *mt, unsigned long *startp,
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void *entry, unsigned long size, unsigned long min,
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unsigned long max, gfp_t gfp);
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int mtree_alloc_rrange(struct maple_tree *mt, unsigned long *startp,
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void *entry, unsigned long size, unsigned long min,
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unsigned long max, gfp_t gfp);
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int mtree_store_range(struct maple_tree *mt, unsigned long first,
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unsigned long last, void *entry, gfp_t gfp);
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int mtree_store(struct maple_tree *mt, unsigned long index,
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void *entry, gfp_t gfp);
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void *mtree_erase(struct maple_tree *mt, unsigned long index);
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void mtree_destroy(struct maple_tree *mt);
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void __mt_destroy(struct maple_tree *mt);
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/**
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* mtree_empty() - Determine if a tree has any present entries.
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* @mt: Maple Tree.
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*
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* Context: Any context.
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* Return: %true if the tree contains only NULL pointers.
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*/
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static inline bool mtree_empty(const struct maple_tree *mt)
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{
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return mt->ma_root == NULL;
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}
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/* Advanced API */
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/*
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* The maple state is defined in the struct ma_state and is used to keep track
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* of information during operations, and even between operations when using the
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* advanced API.
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*
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* If state->node has bit 0 set then it references a tree location which is not
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* a node (eg the root). If bit 1 is set, the rest of the bits are a negative
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* errno. Bit 2 (the 'unallocated slots' bit) is clear. Bits 3-6 indicate the
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* node type.
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*
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* state->alloc either has a request number of nodes or an allocated node. If
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* stat->alloc has a requested number of nodes, the first bit will be set (0x1)
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* and the remaining bits are the value. If state->alloc is a node, then the
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* node will be of type maple_alloc. maple_alloc has MAPLE_NODE_SLOTS - 1 for
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* storing more allocated nodes, a total number of nodes allocated, and the
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* node_count in this node. node_count is the number of allocated nodes in this
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* node. The scaling beyond MAPLE_NODE_SLOTS - 1 is handled by storing further
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* nodes into state->alloc->slot[0]'s node. Nodes are taken from state->alloc
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* by removing a node from the state->alloc node until state->alloc->node_count
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* is 1, when state->alloc is returned and the state->alloc->slot[0] is promoted
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* to state->alloc. Nodes are pushed onto state->alloc by putting the current
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* state->alloc into the pushed node's slot[0].
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*
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* The state also contains the implied min/max of the state->node, the depth of
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* this search, and the offset. The implied min/max are either from the parent
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* node or are 0-oo for the root node. The depth is incremented or decremented
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* every time a node is walked down or up. The offset is the slot/pivot of
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* interest in the node - either for reading or writing.
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*
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* When returning a value the maple state index and last respectively contain
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* the start and end of the range for the entry. Ranges are inclusive in the
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* Maple Tree.
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*/
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struct ma_state {
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struct maple_tree *tree; /* The tree we're operating in */
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unsigned long index; /* The index we're operating on - range start */
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unsigned long last; /* The last index we're operating on - range end */
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struct maple_enode *node; /* The node containing this entry */
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unsigned long min; /* The minimum index of this node - implied pivot min */
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unsigned long max; /* The maximum index of this node - implied pivot max */
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struct maple_alloc *alloc; /* Allocated nodes for this operation */
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unsigned char depth; /* depth of tree descent during write */
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unsigned char offset;
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unsigned char mas_flags;
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};
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struct ma_wr_state {
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struct ma_state *mas;
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struct maple_node *node; /* Decoded mas->node */
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unsigned long r_min; /* range min */
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unsigned long r_max; /* range max */
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enum maple_type type; /* mas->node type */
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unsigned char offset_end; /* The offset where the write ends */
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unsigned char node_end; /* mas->node end */
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unsigned long *pivots; /* mas->node->pivots pointer */
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||
|
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_unlock(mas) spin_unlock(&((mas)->tree->ma_lock))
|
||
|
|
||
|
|
||
|
/*
|
||
|
* Special values for ma_state.node.
|
||
|
* MAS_START means we have not searched the tree.
|
||
|
* MAS_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).
|
||
|
* MAS_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_ERROR represents an errno. After dropping the lock and attempting
|
||
|
* to resolve the error, the walk would have to be restarted from the
|
||
|
* top of the tree as the tree may have been modified.
|
||
|
*/
|
||
|
#define MAS_START ((struct maple_enode *)1UL)
|
||
|
#define MAS_ROOT ((struct maple_enode *)5UL)
|
||
|
#define MAS_NONE ((struct maple_enode *)9UL)
|
||
|
#define MAS_PAUSE ((struct maple_enode *)17UL)
|
||
|
#define MA_ERROR(err) \
|
||
|
((struct maple_enode *)(((unsigned long)err << 2) | 2UL))
|
||
|
|
||
|
#define MA_STATE(name, mt, first, end) \
|
||
|
struct ma_state name = { \
|
||
|
.tree = mt, \
|
||
|
.index = first, \
|
||
|
.last = end, \
|
||
|
.node = MAS_START, \
|
||
|
.min = 0, \
|
||
|
.max = ULONG_MAX, \
|
||
|
.alloc = NULL, \
|
||
|
.mas_flags = 0, \
|
||
|
}
|
||
|
|
||
|
#define MA_WR_STATE(name, ma_state, wr_entry) \
|
||
|
struct ma_wr_state name = { \
|
||
|
.mas = ma_state, \
|
||
|
.content = NULL, \
|
||
|
.entry = wr_entry, \
|
||
|
}
|
||
|
|
||
|
#define MA_TOPIARY(name, tree) \
|
||
|
struct ma_topiary name = { \
|
||
|
.head = NULL, \
|
||
|
.tail = NULL, \
|
||
|
.mtree = tree, \
|
||
|
}
|
||
|
|
||
|
void *mas_walk(struct ma_state *mas);
|
||
|
void *mas_store(struct ma_state *mas, void *entry);
|
||
|
void *mas_erase(struct ma_state *mas);
|
||
|
int mas_store_gfp(struct ma_state *mas, void *entry, gfp_t gfp);
|
||
|
void mas_store_prealloc(struct ma_state *mas, void *entry);
|
||
|
void *mas_find(struct ma_state *mas, unsigned long max);
|
||
|
void *mas_find_rev(struct ma_state *mas, unsigned long min);
|
||
|
int mas_preallocate(struct ma_state *mas, gfp_t gfp);
|
||
|
bool mas_is_err(struct ma_state *mas);
|
||
|
|
||
|
bool mas_nomem(struct ma_state *mas, gfp_t gfp);
|
||
|
void mas_pause(struct ma_state *mas);
|
||
|
void maple_tree_init(void);
|
||
|
void mas_destroy(struct ma_state *mas);
|
||
|
int mas_expected_entries(struct ma_state *mas, unsigned long nr_entries);
|
||
|
|
||
|
void *mas_prev(struct ma_state *mas, unsigned long min);
|
||
|
void *mas_next(struct ma_state *mas, unsigned long max);
|
||
|
|
||
|
int mas_empty_area(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->node = MAS_START;
|
||
|
}
|
||
|
|
||
|
/* Checks if a mas has not found anything */
|
||
|
static inline bool mas_is_none(struct ma_state *mas)
|
||
|
{
|
||
|
return mas->node == MAS_NONE;
|
||
|
}
|
||
|
|
||
|
/* Checks if a mas has been paused */
|
||
|
static inline bool mas_is_paused(struct ma_state *mas)
|
||
|
{
|
||
|
return mas->node == MAS_PAUSE;
|
||
|
}
|
||
|
|
||
|
/*
|
||
|
* This finds an empty area from the highest address to the lowest.
|
||
|
* AKA "Topdown" version,
|
||
|
*/
|
||
|
int mas_empty_area_rev(struct ma_state *mas, unsigned long min,
|
||
|
unsigned long max, unsigned long size);
|
||
|
/**
|
||
|
* mas_reset() - Reset a Maple Tree operation state.
|
||
|
* @mas: Maple Tree operation state.
|
||
|
*
|
||
|
* Resets the error or walk state of the @mas so future walks of the
|
||
|
* array will start from the root. Use this if you have dropped the
|
||
|
* lock and want to reuse the ma_state.
|
||
|
*
|
||
|
* Context: Any context.
|
||
|
*/
|
||
|
static inline void mas_reset(struct ma_state *mas)
|
||
|
{
|
||
|
mas->node = MAS_START;
|
||
|
}
|
||
|
|
||
|
/**
|
||
|
* mas_for_each() - Iterate over a range of the maple tree.
|
||
|
* @__mas: Maple Tree operation state (maple_state)
|
||
|
* @__entry: Entry retrieved from the tree
|
||
|
* @__max: maximum index to retrieve from the tree
|
||
|
*
|
||
|
* When returned, mas->index and mas->last will hold the entire range for the
|
||
|
* entry.
|
||
|
*
|
||
|
* Note: may return the zero entry.
|
||
|
*/
|
||
|
#define mas_for_each(__mas, __entry, __max) \
|
||
|
while (((__entry) = mas_find((__mas), (__max))) != NULL)
|
||
|
|
||
|
|
||
|
/**
|
||
|
* mas_set_range() - Set up Maple Tree operation state for a different index.
|
||
|
* @mas: Maple Tree operation state.
|
||
|
* @start: New start of range in the Maple Tree.
|
||
|
* @last: New end of range in the Maple Tree.
|
||
|
*
|
||
|
* Move the operation state to refer to a different range. This will
|
||
|
* have the effect of starting a walk from the top; see mas_next()
|
||
|
* to move to an adjacent index.
|
||
|
*/
|
||
|
static inline
|
||
|
void mas_set_range(struct ma_state *mas, unsigned long start, unsigned long last)
|
||
|
{
|
||
|
mas->index = start;
|
||
|
mas->last = last;
|
||
|
mas->node = MAS_START;
|
||
|
}
|
||
|
|
||
|
/**
|
||
|
* mas_set() - Set up Maple Tree operation state for a different index.
|
||
|
* @mas: Maple Tree operation state.
|
||
|
* @index: New index into the Maple Tree.
|
||
|
*
|
||
|
* Move the operation state to refer to a different index. This will
|
||
|
* have the effect of starting a walk from the top; see mas_next()
|
||
|
* to move to an adjacent index.
|
||
|
*/
|
||
|
static inline void mas_set(struct ma_state *mas, unsigned long index)
|
||
|
{
|
||
|
|
||
|
mas_set_range(mas, index, index);
|
||
|
}
|
||
|
|
||
|
static inline bool mt_external_lock(const struct maple_tree *mt)
|
||
|
{
|
||
|
return (mt->ma_flags & MT_FLAGS_LOCK_MASK) == MT_FLAGS_LOCK_EXTERN;
|
||
|
}
|
||
|
|
||
|
/**
|
||
|
* mt_init_flags() - Initialise an empty maple tree with flags.
|
||
|
* @mt: Maple Tree
|
||
|
* @flags: maple tree flags.
|
||
|
*
|
||
|
* If you need to initialise a Maple Tree with special flags (eg, an
|
||
|
* allocation tree), use this function.
|
||
|
*
|
||
|
* Context: Any context.
|
||
|
*/
|
||
|
static inline void mt_init_flags(struct maple_tree *mt, unsigned int flags)
|
||
|
{
|
||
|
mt->ma_flags = flags;
|
||
|
if (!mt_external_lock(mt))
|
||
|
spin_lock_init(&mt->ma_lock);
|
||
|
rcu_assign_pointer(mt->ma_root, NULL);
|
||
|
}
|
||
|
|
||
|
/**
|
||
|
* mt_init() - Initialise an empty maple tree.
|
||
|
* @mt: Maple Tree
|
||
|
*
|
||
|
* An empty Maple Tree.
|
||
|
*
|
||
|
* Context: Any context.
|
||
|
*/
|
||
|
static inline void mt_init(struct maple_tree *mt)
|
||
|
{
|
||
|
mt_init_flags(mt, 0);
|
||
|
}
|
||
|
|
||
|
static inline bool mt_in_rcu(struct maple_tree *mt)
|
||
|
{
|
||
|
#ifdef CONFIG_MAPLE_RCU_DISABLED
|
||
|
return false;
|
||
|
#endif
|
||
|
return mt->ma_flags & MT_FLAGS_USE_RCU;
|
||
|
}
|
||
|
|
||
|
/**
|
||
|
* mt_clear_in_rcu() - Switch the tree to non-RCU mode.
|
||
|
* @mt: The Maple Tree
|
||
|
*/
|
||
|
static inline void mt_clear_in_rcu(struct maple_tree *mt)
|
||
|
{
|
||
|
if (!mt_in_rcu(mt))
|
||
|
return;
|
||
|
|
||
|
if (mt_external_lock(mt)) {
|
||
|
BUG_ON(!mt_lock_is_held(mt));
|
||
|
mt->ma_flags &= ~MT_FLAGS_USE_RCU;
|
||
|
} else {
|
||
|
mtree_lock(mt);
|
||
|
mt->ma_flags &= ~MT_FLAGS_USE_RCU;
|
||
|
mtree_unlock(mt);
|
||
|
}
|
||
|
}
|
||
|
|
||
|
/**
|
||
|
* mt_set_in_rcu() - Switch the tree to RCU safe mode.
|
||
|
* @mt: The Maple Tree
|
||
|
*/
|
||
|
static inline void mt_set_in_rcu(struct maple_tree *mt)
|
||
|
{
|
||
|
if (mt_in_rcu(mt))
|
||
|
return;
|
||
|
|
||
|
if (mt_external_lock(mt)) {
|
||
|
BUG_ON(!mt_lock_is_held(mt));
|
||
|
mt->ma_flags |= MT_FLAGS_USE_RCU;
|
||
|
} else {
|
||
|
mtree_lock(mt);
|
||
|
mt->ma_flags |= MT_FLAGS_USE_RCU;
|
||
|
mtree_unlock(mt);
|
||
|
}
|
||
|
}
|
||
|
|
||
|
static inline unsigned int mt_height(const struct maple_tree *mt)
|
||
|
{
|
||
|
return (mt->ma_flags & MT_FLAGS_HEIGHT_MASK) >> MT_FLAGS_HEIGHT_OFFSET;
|
||
|
}
|
||
|
|
||
|
void *mt_find(struct maple_tree *mt, unsigned long *index, unsigned long max);
|
||
|
void *mt_find_after(struct maple_tree *mt, unsigned long *index,
|
||
|
unsigned long max);
|
||
|
void *mt_prev(struct maple_tree *mt, unsigned long index, unsigned long min);
|
||
|
void *mt_next(struct maple_tree *mt, unsigned long index, unsigned long max);
|
||
|
|
||
|
/**
|
||
|
* mt_for_each - Iterate over each entry starting at index until max.
|
||
|
* @__tree: The Maple Tree
|
||
|
* @__entry: The current entry
|
||
|
* @__index: The index to update to track the location in the tree
|
||
|
* @__max: The maximum limit for @index
|
||
|
*
|
||
|
* Note: Will not return the zero entry.
|
||
|
*/
|
||
|
#define mt_for_each(__tree, __entry, __index, __max) \
|
||
|
for (__entry = mt_find(__tree, &(__index), __max); \
|
||
|
__entry; __entry = mt_find_after(__tree, &(__index), __max))
|
||
|
|
||
|
|
||
|
#ifdef CONFIG_DEBUG_MAPLE_TREE
|
||
|
extern atomic_t maple_tree_tests_run;
|
||
|
extern atomic_t maple_tree_tests_passed;
|
||
|
|
||
|
void mt_dump(const struct maple_tree *mt);
|
||
|
void mt_validate(struct maple_tree *mt);
|
||
|
void mt_cache_shrink(void);
|
||
|
#define MT_BUG_ON(__tree, __x) do { \
|
||
|
atomic_inc(&maple_tree_tests_run); \
|
||
|
if (__x) { \
|
||
|
pr_info("BUG at %s:%d (%u)\n", \
|
||
|
__func__, __LINE__, __x); \
|
||
|
mt_dump(__tree); \
|
||
|
pr_info("Pass: %u Run:%u\n", \
|
||
|
atomic_read(&maple_tree_tests_passed), \
|
||
|
atomic_read(&maple_tree_tests_run)); \
|
||
|
dump_stack(); \
|
||
|
} else { \
|
||
|
atomic_inc(&maple_tree_tests_passed); \
|
||
|
} \
|
||
|
} while (0)
|
||
|
#else
|
||
|
#define MT_BUG_ON(__tree, __x) BUG_ON(__x)
|
||
|
#endif /* CONFIG_DEBUG_MAPLE_TREE */
|
||
|
|
||
|
#endif /*_LINUX_MAPLE_TREE_H */
|