| /* SPDX-License-Identifier: GPL-2.0+ */ |
| #ifndef _LINUX_XARRAY_H |
| #define _LINUX_XARRAY_H |
| /* |
| * eXtensible Arrays |
| * Copyright (c) 2017 Microsoft Corporation |
| * Author: Matthew Wilcox <willy@infradead.org> |
| * |
| * See Documentation/core-api/xarray.rst for how to use the XArray. |
| */ |
| |
| #include <linux/bug.h> |
| #include <linux/compiler.h> |
| #include <linux/gfp.h> |
| #include <linux/kconfig.h> |
| #include <linux/kernel.h> |
| #include <linux/rcupdate.h> |
| #include <linux/spinlock.h> |
| #include <linux/types.h> |
| |
| /* |
| * The bottom two bits of the entry determine how the XArray interprets |
| * the contents: |
| * |
| * 00: Pointer entry |
| * 10: Internal entry |
| * x1: Value entry or tagged pointer |
| * |
| * Attempting to store internal entries in the XArray is a bug. |
| * |
| * Most internal entries are pointers to the next node in the tree. |
| * The following internal entries have a special meaning: |
| * |
| * 0-62: Sibling entries |
| * 256: Retry entry |
| * 257: Zero entry |
| * |
| * Errors are also represented as internal entries, but use the negative |
| * space (-4094 to -2). They're never stored in the slots array; only |
| * returned by the normal API. |
| */ |
| |
| #define BITS_PER_XA_VALUE (BITS_PER_LONG - 1) |
| |
| /** |
| * xa_mk_value() - Create an XArray entry from an integer. |
| * @v: Value to store in XArray. |
| * |
| * Context: Any context. |
| * Return: An entry suitable for storing in the XArray. |
| */ |
| static inline void *xa_mk_value(unsigned long v) |
| { |
| WARN_ON((long)v < 0); |
| return (void *)((v << 1) | 1); |
| } |
| |
| /** |
| * xa_to_value() - Get value stored in an XArray entry. |
| * @entry: XArray entry. |
| * |
| * Context: Any context. |
| * Return: The value stored in the XArray entry. |
| */ |
| static inline unsigned long xa_to_value(const void *entry) |
| { |
| return (unsigned long)entry >> 1; |
| } |
| |
| /** |
| * xa_is_value() - Determine if an entry is a value. |
| * @entry: XArray entry. |
| * |
| * Context: Any context. |
| * Return: True if the entry is a value, false if it is a pointer. |
| */ |
| static inline bool xa_is_value(const void *entry) |
| { |
| return (unsigned long)entry & 1; |
| } |
| |
| /** |
| * xa_tag_pointer() - Create an XArray entry for a tagged pointer. |
| * @p: Plain pointer. |
| * @tag: Tag value (0, 1 or 3). |
| * |
| * If the user of the XArray prefers, they can tag their pointers instead |
| * of storing value entries. Three tags are available (0, 1 and 3). |
| * These are distinct from the xa_mark_t as they are not replicated up |
| * through the array and cannot be searched for. |
| * |
| * Context: Any context. |
| * Return: An XArray entry. |
| */ |
| static inline void *xa_tag_pointer(void *p, unsigned long tag) |
| { |
| return (void *)((unsigned long)p | tag); |
| } |
| |
| /** |
| * xa_untag_pointer() - Turn an XArray entry into a plain pointer. |
| * @entry: XArray entry. |
| * |
| * If you have stored a tagged pointer in the XArray, call this function |
| * to get the untagged version of the pointer. |
| * |
| * Context: Any context. |
| * Return: A pointer. |
| */ |
| static inline void *xa_untag_pointer(void *entry) |
| { |
| return (void *)((unsigned long)entry & ~3UL); |
| } |
| |
| /** |
| * xa_pointer_tag() - Get the tag stored in an XArray entry. |
| * @entry: XArray entry. |
| * |
| * If you have stored a tagged pointer in the XArray, call this function |
| * to get the tag of that pointer. |
| * |
| * Context: Any context. |
| * Return: A tag. |
| */ |
| static inline unsigned int xa_pointer_tag(void *entry) |
| { |
| return (unsigned long)entry & 3UL; |
| } |
| |
| /* |
| * xa_mk_internal() - Create an internal entry. |
| * @v: Value to turn into an internal entry. |
| * |
| * Internal entries are used for a number of purposes. Entries 0-255 are |
| * used for sibling entries (only 0-62 are used by the current code). 256 |
| * is used for the retry entry. 257 is used for the reserved / zero entry. |
| * Negative internal entries are used to represent errnos. Node pointers |
| * are also tagged as internal entries in some situations. |
| * |
| * Context: Any context. |
| * Return: An XArray internal entry corresponding to this value. |
| */ |
| static inline void *xa_mk_internal(unsigned long v) |
| { |
| return (void *)((v << 2) | 2); |
| } |
| |
| /* |
| * xa_to_internal() - Extract the value from an internal entry. |
| * @entry: XArray entry. |
| * |
| * Context: Any context. |
| * Return: The value which was stored in the internal entry. |
| */ |
| static inline unsigned long xa_to_internal(const void *entry) |
| { |
| return (unsigned long)entry >> 2; |
| } |
| |
| /* |
| * xa_is_internal() - Is the entry an internal entry? |
| * @entry: XArray entry. |
| * |
| * Context: Any context. |
| * Return: %true if the entry is an internal entry. |
| */ |
| static inline bool xa_is_internal(const void *entry) |
| { |
| return ((unsigned long)entry & 3) == 2; |
| } |
| |
| #define XA_ZERO_ENTRY xa_mk_internal(257) |
| |
| /** |
| * xa_is_zero() - Is the entry a zero entry? |
| * @entry: Entry retrieved from the XArray |
| * |
| * The normal API will return NULL as the contents of a slot containing |
| * a zero entry. You can only see zero entries by using the advanced API. |
| * |
| * Return: %true if the entry is a zero entry. |
| */ |
| static inline bool xa_is_zero(const void *entry) |
| { |
| return unlikely(entry == XA_ZERO_ENTRY); |
| } |
| |
| /** |
| * xa_is_err() - Report whether an XArray operation returned an error |
| * @entry: Result from calling an XArray function |
| * |
| * If an XArray operation cannot complete an operation, it will return |
| * a special value indicating an error. This function tells you |
| * whether an error occurred; xa_err() tells you which error occurred. |
| * |
| * Context: Any context. |
| * Return: %true if the entry indicates an error. |
| */ |
| static inline bool xa_is_err(const void *entry) |
| { |
| return unlikely(xa_is_internal(entry) && |
| entry >= xa_mk_internal(-MAX_ERRNO)); |
| } |
| |
| /** |
| * xa_err() - Turn an XArray result into an errno. |
| * @entry: Result from calling an XArray function. |
| * |
| * If an XArray operation cannot complete an operation, it will return |
| * a special pointer value which encodes an errno. This function extracts |
| * the errno from the pointer value, or returns 0 if the pointer does not |
| * represent an errno. |
| * |
| * Context: Any context. |
| * Return: A negative errno or 0. |
| */ |
| static inline int xa_err(void *entry) |
| { |
| /* xa_to_internal() would not do sign extension. */ |
| if (xa_is_err(entry)) |
| return (long)entry >> 2; |
| return 0; |
| } |
| |
| /** |
| * struct xa_limit - Represents a range of IDs. |
| * @min: The lowest ID to allocate (inclusive). |
| * @max: The maximum ID to allocate (inclusive). |
| * |
| * This structure is used either directly or via the XA_LIMIT() macro |
| * to communicate the range of IDs that are valid for allocation. |
| * Three common ranges are predefined for you: |
| * * xa_limit_32b - [0 - UINT_MAX] |
| * * xa_limit_31b - [0 - INT_MAX] |
| * * xa_limit_16b - [0 - USHRT_MAX] |
| */ |
| struct xa_limit { |
| u32 max; |
| u32 min; |
| }; |
| |
| #define XA_LIMIT(_min, _max) (struct xa_limit) { .min = _min, .max = _max } |
| |
| #define xa_limit_32b XA_LIMIT(0, UINT_MAX) |
| #define xa_limit_31b XA_LIMIT(0, INT_MAX) |
| #define xa_limit_16b XA_LIMIT(0, USHRT_MAX) |
| |
| typedef unsigned __bitwise xa_mark_t; |
| #define XA_MARK_0 ((__force xa_mark_t)0U) |
| #define XA_MARK_1 ((__force xa_mark_t)1U) |
| #define XA_MARK_2 ((__force xa_mark_t)2U) |
| #define XA_PRESENT ((__force xa_mark_t)8U) |
| #define XA_MARK_MAX XA_MARK_2 |
| #define XA_FREE_MARK XA_MARK_0 |
| |
| enum xa_lock_type { |
| XA_LOCK_IRQ = 1, |
| XA_LOCK_BH = 2, |
| }; |
| |
| /* |
| * Values for xa_flags. The radix tree stores its GFP flags in the xa_flags, |
| * and we remain compatible with that. |
| */ |
| #define XA_FLAGS_LOCK_IRQ ((__force gfp_t)XA_LOCK_IRQ) |
| #define XA_FLAGS_LOCK_BH ((__force gfp_t)XA_LOCK_BH) |
| #define XA_FLAGS_TRACK_FREE ((__force gfp_t)4U) |
| #define XA_FLAGS_ZERO_BUSY ((__force gfp_t)8U) |
| #define XA_FLAGS_ALLOC_WRAPPED ((__force gfp_t)16U) |
| #define XA_FLAGS_ACCOUNT ((__force gfp_t)32U) |
| #define XA_FLAGS_MARK(mark) ((__force gfp_t)((1U << __GFP_BITS_SHIFT) << \ |
| (__force unsigned)(mark))) |
| |
| /* ALLOC is for a normal 0-based alloc. ALLOC1 is for an 1-based alloc */ |
| #define XA_FLAGS_ALLOC (XA_FLAGS_TRACK_FREE | XA_FLAGS_MARK(XA_FREE_MARK)) |
| #define XA_FLAGS_ALLOC1 (XA_FLAGS_TRACK_FREE | XA_FLAGS_ZERO_BUSY) |
| |
| /** |
| * struct xarray - The anchor of the XArray. |
| * @xa_lock: Lock that protects the contents of the XArray. |
| * |
| * To use the xarray, define it statically or embed it in your data structure. |
| * It is a very small data structure, so it does not usually make sense to |
| * allocate it separately and keep a pointer to it in your data structure. |
| * |
| * You may use the xa_lock to protect your own data structures as well. |
| */ |
| /* |
| * If all of the entries in the array are NULL, @xa_head is a NULL pointer. |
| * If the only non-NULL entry in the array is at index 0, @xa_head is that |
| * entry. If any other entry in the array is non-NULL, @xa_head points |
| * to an @xa_node. |
| */ |
| struct xarray { |
| spinlock_t xa_lock; |
| /* private: The rest of the data structure is not to be used directly. */ |
| gfp_t xa_flags; |
| void __rcu * xa_head; |
| }; |
| |
| #define XARRAY_INIT(name, flags) { \ |
| .xa_lock = __SPIN_LOCK_UNLOCKED(name.xa_lock), \ |
| .xa_flags = flags, \ |
| .xa_head = NULL, \ |
| } |
| |
| /** |
| * DEFINE_XARRAY_FLAGS() - Define an XArray with custom flags. |
| * @name: A string that names your XArray. |
| * @flags: XA_FLAG values. |
| * |
| * This is intended for file scope definitions of XArrays. It declares |
| * and initialises an empty XArray with the chosen name and flags. It is |
| * equivalent to calling xa_init_flags() on the array, but it does the |
| * initialisation at compiletime instead of runtime. |
| */ |
| #define DEFINE_XARRAY_FLAGS(name, flags) \ |
| struct xarray name = XARRAY_INIT(name, flags) |
| |
| /** |
| * DEFINE_XARRAY() - Define an XArray. |
| * @name: A string that names your XArray. |
| * |
| * This is intended for file scope definitions of XArrays. It declares |
| * and initialises an empty XArray with the chosen name. It is equivalent |
| * to calling xa_init() on the array, but it does the initialisation at |
| * compiletime instead of runtime. |
| */ |
| #define DEFINE_XARRAY(name) DEFINE_XARRAY_FLAGS(name, 0) |
| |
| /** |
| * DEFINE_XARRAY_ALLOC() - Define an XArray which allocates IDs starting at 0. |
| * @name: A string that names your XArray. |
| * |
| * This is intended for file scope definitions of allocating XArrays. |
| * See also DEFINE_XARRAY(). |
| */ |
| #define DEFINE_XARRAY_ALLOC(name) DEFINE_XARRAY_FLAGS(name, XA_FLAGS_ALLOC) |
| |
| /** |
| * DEFINE_XARRAY_ALLOC1() - Define an XArray which allocates IDs starting at 1. |
| * @name: A string that names your XArray. |
| * |
| * This is intended for file scope definitions of allocating XArrays. |
| * See also DEFINE_XARRAY(). |
| */ |
| #define DEFINE_XARRAY_ALLOC1(name) DEFINE_XARRAY_FLAGS(name, XA_FLAGS_ALLOC1) |
| |
| void *xa_load(struct xarray *, unsigned long index); |
| void *xa_store(struct xarray *, unsigned long index, void *entry, gfp_t); |
| void *xa_erase(struct xarray *, unsigned long index); |
| void *xa_store_range(struct xarray *, unsigned long first, unsigned long last, |
| void *entry, gfp_t); |
| bool xa_get_mark(struct xarray *, unsigned long index, xa_mark_t); |
| void xa_set_mark(struct xarray *, unsigned long index, xa_mark_t); |
| void xa_clear_mark(struct xarray *, unsigned long index, xa_mark_t); |
| void *xa_find(struct xarray *xa, unsigned long *index, |
| unsigned long max, xa_mark_t) __attribute__((nonnull(2))); |
| void *xa_find_after(struct xarray *xa, unsigned long *index, |
| unsigned long max, xa_mark_t) __attribute__((nonnull(2))); |
| unsigned int xa_extract(struct xarray *, void **dst, unsigned long start, |
| unsigned long max, unsigned int n, xa_mark_t); |
| void xa_destroy(struct xarray *); |
| |
| /** |
| * xa_init_flags() - Initialise an empty XArray with flags. |
| * @xa: XArray. |
| * @flags: XA_FLAG values. |
| * |
| * If you need to initialise an XArray with special flags (eg you need |
| * to take the lock from interrupt context), use this function instead |
| * of xa_init(). |
| * |
| * Context: Any context. |
| */ |
| static inline void xa_init_flags(struct xarray *xa, gfp_t flags) |
| { |
| spin_lock_init(&xa->xa_lock); |
| xa->xa_flags = flags; |
| xa->xa_head = NULL; |
| } |
| |
| /** |
| * xa_init() - Initialise an empty XArray. |
| * @xa: XArray. |
| * |
| * An empty XArray is full of NULL entries. |
| * |
| * Context: Any context. |
| */ |
| static inline void xa_init(struct xarray *xa) |
| { |
| xa_init_flags(xa, 0); |
| } |
| |
| /** |
| * xa_empty() - Determine if an array has any present entries. |
| * @xa: XArray. |
| * |
| * Context: Any context. |
| * Return: %true if the array contains only NULL pointers. |
| */ |
| static inline bool xa_empty(const struct xarray *xa) |
| { |
| return xa->xa_head == NULL; |
| } |
| |
| /** |
| * xa_marked() - Inquire whether any entry in this array has a mark set |
| * @xa: Array |
| * @mark: Mark value |
| * |
| * Context: Any context. |
| * Return: %true if any entry has this mark set. |
| */ |
| static inline bool xa_marked(const struct xarray *xa, xa_mark_t mark) |
| { |
| return xa->xa_flags & XA_FLAGS_MARK(mark); |
| } |
| |
| /** |
| * xa_for_each_range() - Iterate over a portion of an XArray. |
| * @xa: XArray. |
| * @index: Index of @entry. |
| * @entry: Entry retrieved from array. |
| * @start: First index to retrieve from array. |
| * @last: Last index to retrieve from array. |
| * |
| * During the iteration, @entry will have the value of the entry stored |
| * in @xa at @index. You may modify @index during the iteration if you |
| * want to skip or reprocess indices. It is safe to modify the array |
| * during the iteration. At the end of the iteration, @entry will be set |
| * to NULL and @index will have a value less than or equal to max. |
| * |
| * xa_for_each_range() is O(n.log(n)) while xas_for_each() is O(n). You have |
| * to handle your own locking with xas_for_each(), and if you have to unlock |
| * after each iteration, it will also end up being O(n.log(n)). |
| * xa_for_each_range() will spin if it hits a retry entry; if you intend to |
| * see retry entries, you should use the xas_for_each() iterator instead. |
| * The xas_for_each() iterator will expand into more inline code than |
| * xa_for_each_range(). |
| * |
| * Context: Any context. Takes and releases the RCU lock. |
| */ |
| #define xa_for_each_range(xa, index, entry, start, last) \ |
| for (index = start, \ |
| entry = xa_find(xa, &index, last, XA_PRESENT); \ |
| entry; \ |
| entry = xa_find_after(xa, &index, last, XA_PRESENT)) |
| |
| /** |
| * xa_for_each_start() - Iterate over a portion of an XArray. |
| * @xa: XArray. |
| * @index: Index of @entry. |
| * @entry: Entry retrieved from array. |
| * @start: First index to retrieve from array. |
| * |
| * During the iteration, @entry will have the value of the entry stored |
| * in @xa at @index. You may modify @index during the iteration if you |
| * want to skip or reprocess indices. It is safe to modify the array |
| * during the iteration. At the end of the iteration, @entry will be set |
| * to NULL and @index will have a value less than or equal to max. |
| * |
| * xa_for_each_start() is O(n.log(n)) while xas_for_each() is O(n). You have |
| * to handle your own locking with xas_for_each(), and if you have to unlock |
| * after each iteration, it will also end up being O(n.log(n)). |
| * xa_for_each_start() will spin if it hits a retry entry; if you intend to |
| * see retry entries, you should use the xas_for_each() iterator instead. |
| * The xas_for_each() iterator will expand into more inline code than |
| * xa_for_each_start(). |
| * |
| * Context: Any context. Takes and releases the RCU lock. |
| */ |
| #define xa_for_each_start(xa, index, entry, start) \ |
| xa_for_each_range(xa, index, entry, start, ULONG_MAX) |
| |
| /** |
| * xa_for_each() - Iterate over present entries in an XArray. |
| * @xa: XArray. |
| * @index: Index of @entry. |
| * @entry: Entry retrieved from array. |
| * |
| * During the iteration, @entry will have the value of the entry stored |
| * in @xa at @index. You may modify @index during the iteration if you want |
| * to skip or reprocess indices. It is safe to modify the array during the |
| * iteration. At the end of the iteration, @entry will be set to NULL and |
| * @index will have a value less than or equal to max. |
| * |
| * xa_for_each() is O(n.log(n)) while xas_for_each() is O(n). You have |
| * to handle your own locking with xas_for_each(), and if you have to unlock |
| * after each iteration, it will also end up being O(n.log(n)). xa_for_each() |
| * will spin if it hits a retry entry; if you intend to see retry entries, |
| * you should use the xas_for_each() iterator instead. The xas_for_each() |
| * iterator will expand into more inline code than xa_for_each(). |
| * |
| * Context: Any context. Takes and releases the RCU lock. |
| */ |
| #define xa_for_each(xa, index, entry) \ |
| xa_for_each_start(xa, index, entry, 0) |
| |
| /** |
| * xa_for_each_marked() - Iterate over marked entries in an XArray. |
| * @xa: XArray. |
| * @index: Index of @entry. |
| * @entry: Entry retrieved from array. |
| * @filter: Selection criterion. |
| * |
| * During the iteration, @entry will have the value of the entry stored |
| * in @xa at @index. The iteration will skip all entries in the array |
| * which do not match @filter. You may modify @index during the iteration |
| * if you want to skip or reprocess indices. It is safe to modify the array |
| * during the iteration. At the end of the iteration, @entry will be set to |
| * NULL and @index will have a value less than or equal to max. |
| * |
| * xa_for_each_marked() is O(n.log(n)) while xas_for_each_marked() is O(n). |
| * You have to handle your own locking with xas_for_each(), and if you have |
| * to unlock after each iteration, it will also end up being O(n.log(n)). |
| * xa_for_each_marked() will spin if it hits a retry entry; if you intend to |
| * see retry entries, you should use the xas_for_each_marked() iterator |
| * instead. The xas_for_each_marked() iterator will expand into more inline |
| * code than xa_for_each_marked(). |
| * |
| * Context: Any context. Takes and releases the RCU lock. |
| */ |
| #define xa_for_each_marked(xa, index, entry, filter) \ |
| for (index = 0, entry = xa_find(xa, &index, ULONG_MAX, filter); \ |
| entry; entry = xa_find_after(xa, &index, ULONG_MAX, filter)) |
| |
| #define xa_trylock(xa) spin_trylock(&(xa)->xa_lock) |
| #define xa_lock(xa) spin_lock(&(xa)->xa_lock) |
| #define xa_unlock(xa) spin_unlock(&(xa)->xa_lock) |
| #define xa_lock_bh(xa) spin_lock_bh(&(xa)->xa_lock) |
| #define xa_unlock_bh(xa) spin_unlock_bh(&(xa)->xa_lock) |
| #define xa_lock_irq(xa) spin_lock_irq(&(xa)->xa_lock) |
| #define xa_unlock_irq(xa) spin_unlock_irq(&(xa)->xa_lock) |
| #define xa_lock_irqsave(xa, flags) \ |
| spin_lock_irqsave(&(xa)->xa_lock, flags) |
| #define xa_unlock_irqrestore(xa, flags) \ |
| spin_unlock_irqrestore(&(xa)->xa_lock, flags) |
| #define xa_lock_nested(xa, subclass) \ |
| spin_lock_nested(&(xa)->xa_lock, subclass) |
| #define xa_lock_bh_nested(xa, subclass) \ |
| spin_lock_bh_nested(&(xa)->xa_lock, subclass) |
| #define xa_lock_irq_nested(xa, subclass) \ |
| spin_lock_irq_nested(&(xa)->xa_lock, subclass) |
| #define xa_lock_irqsave_nested(xa, flags, subclass) \ |
| spin_lock_irqsave_nested(&(xa)->xa_lock, flags, subclass) |
| |
| /* |
| * Versions of the normal API which require the caller to hold the |
| * xa_lock. If the GFP flags allow it, they will drop the lock to |
| * allocate memory, then reacquire it afterwards. These functions |
| * may also re-enable interrupts if the XArray flags indicate the |
| * locking should be interrupt safe. |
| */ |
| void *__xa_erase(struct xarray *, unsigned long index); |
| void *__xa_store(struct xarray *, unsigned long index, void *entry, gfp_t); |
| void *__xa_cmpxchg(struct xarray *, unsigned long index, void *old, |
| void *entry, gfp_t); |
| int __must_check __xa_insert(struct xarray *, unsigned long index, |
| void *entry, gfp_t); |
| int __must_check __xa_alloc(struct xarray *, u32 *id, void *entry, |
| struct xa_limit, gfp_t); |
| int __must_check __xa_alloc_cyclic(struct xarray *, u32 *id, void *entry, |
| struct xa_limit, u32 *next, gfp_t); |
| void __xa_set_mark(struct xarray *, unsigned long index, xa_mark_t); |
| void __xa_clear_mark(struct xarray *, unsigned long index, xa_mark_t); |
| |
| /** |
| * xa_store_bh() - Store this entry in the XArray. |
| * @xa: XArray. |
| * @index: Index into array. |
| * @entry: New entry. |
| * @gfp: Memory allocation flags. |
| * |
| * This function is like calling xa_store() except it disables softirqs |
| * while holding the array lock. |
| * |
| * Context: Any context. Takes and releases the xa_lock while |
| * disabling softirqs. |
| * Return: The old entry at this index or xa_err() if an error happened. |
| */ |
| static inline void *xa_store_bh(struct xarray *xa, unsigned long index, |
| void *entry, gfp_t gfp) |
| { |
| void *curr; |
| |
| xa_lock_bh(xa); |
| curr = __xa_store(xa, index, entry, gfp); |
| xa_unlock_bh(xa); |
| |
| return curr; |
| } |
| |
| /** |
| * xa_store_irq() - Store this entry in the XArray. |
| * @xa: XArray. |
| * @index: Index into array. |
| * @entry: New entry. |
| * @gfp: Memory allocation flags. |
| * |
| * This function is like calling xa_store() except it disables interrupts |
| * while holding the array lock. |
| * |
| * Context: Process context. Takes and releases the xa_lock while |
| * disabling interrupts. |
| * Return: The old entry at this index or xa_err() if an error happened. |
| */ |
| static inline void *xa_store_irq(struct xarray *xa, unsigned long index, |
| void *entry, gfp_t gfp) |
| { |
| void *curr; |
| |
| xa_lock_irq(xa); |
| curr = __xa_store(xa, index, entry, gfp); |
| xa_unlock_irq(xa); |
| |
| return curr; |
| } |
| |
| /** |
| * xa_erase_bh() - Erase this entry from the XArray. |
| * @xa: XArray. |
| * @index: Index of entry. |
| * |
| * After this function returns, loading from @index will return %NULL. |
| * If the index is part of a multi-index entry, all indices will be erased |
| * and none of the entries will be part of a multi-index entry. |
| * |
| * Context: Any context. Takes and releases the xa_lock while |
| * disabling softirqs. |
| * Return: The entry which used to be at this index. |
| */ |
| static inline void *xa_erase_bh(struct xarray *xa, unsigned long index) |
| { |
| void *entry; |
| |
| xa_lock_bh(xa); |
| entry = __xa_erase(xa, index); |
| xa_unlock_bh(xa); |
| |
| return entry; |
| } |
| |
| /** |
| * xa_erase_irq() - Erase this entry from the XArray. |
| * @xa: XArray. |
| * @index: Index of entry. |
| * |
| * After this function returns, loading from @index will return %NULL. |
| * If the index is part of a multi-index entry, all indices will be erased |
| * and none of the entries will be part of a multi-index entry. |
| * |
| * Context: Process context. Takes and releases the xa_lock while |
| * disabling interrupts. |
| * Return: The entry which used to be at this index. |
| */ |
| static inline void *xa_erase_irq(struct xarray *xa, unsigned long index) |
| { |
| void *entry; |
| |
| xa_lock_irq(xa); |
| entry = __xa_erase(xa, index); |
| xa_unlock_irq(xa); |
| |
| return entry; |
| } |
| |
| /** |
| * xa_cmpxchg() - Conditionally replace an entry in the XArray. |
| * @xa: XArray. |
| * @index: Index into array. |
| * @old: Old value to test against. |
| * @entry: New value to place in array. |
| * @gfp: Memory allocation flags. |
| * |
| * If the entry at @index is the same as @old, replace it with @entry. |
| * If the return value is equal to @old, then the exchange was successful. |
| * |
| * Context: Any context. Takes and releases the xa_lock. May sleep |
| * if the @gfp flags permit. |
| * Return: The old value at this index or xa_err() if an error happened. |
| */ |
| static inline void *xa_cmpxchg(struct xarray *xa, unsigned long index, |
| void *old, void *entry, gfp_t gfp) |
| { |
| void *curr; |
| |
| xa_lock(xa); |
| curr = __xa_cmpxchg(xa, index, old, entry, gfp); |
| xa_unlock(xa); |
| |
| return curr; |
| } |
| |
| /** |
| * xa_cmpxchg_bh() - Conditionally replace an entry in the XArray. |
| * @xa: XArray. |
| * @index: Index into array. |
| * @old: Old value to test against. |
| * @entry: New value to place in array. |
| * @gfp: Memory allocation flags. |
| * |
| * This function is like calling xa_cmpxchg() except it disables softirqs |
| * while holding the array lock. |
| * |
| * Context: Any context. Takes and releases the xa_lock while |
| * disabling softirqs. May sleep if the @gfp flags permit. |
| * Return: The old value at this index or xa_err() if an error happened. |
| */ |
| static inline void *xa_cmpxchg_bh(struct xarray *xa, unsigned long index, |
| void *old, void *entry, gfp_t gfp) |
| { |
| void *curr; |
| |
| xa_lock_bh(xa); |
| curr = __xa_cmpxchg(xa, index, old, entry, gfp); |
| xa_unlock_bh(xa); |
| |
| return curr; |
| } |
| |
| /** |
| * xa_cmpxchg_irq() - Conditionally replace an entry in the XArray. |
| * @xa: XArray. |
| * @index: Index into array. |
| * @old: Old value to test against. |
| * @entry: New value to place in array. |
| * @gfp: Memory allocation flags. |
| * |
| * This function is like calling xa_cmpxchg() except it disables interrupts |
| * while holding the array lock. |
| * |
| * Context: Process context. Takes and releases the xa_lock while |
| * disabling interrupts. May sleep if the @gfp flags permit. |
| * Return: The old value at this index or xa_err() if an error happened. |
| */ |
| static inline void *xa_cmpxchg_irq(struct xarray *xa, unsigned long index, |
| void *old, void *entry, gfp_t gfp) |
| { |
| void *curr; |
| |
| xa_lock_irq(xa); |
| curr = __xa_cmpxchg(xa, index, old, entry, gfp); |
| xa_unlock_irq(xa); |
| |
| return curr; |
| } |
| |
| /** |
| * xa_insert() - Store this entry in the XArray unless another entry is |
| * already present. |
| * @xa: XArray. |
| * @index: Index into array. |
| * @entry: New entry. |
| * @gfp: Memory allocation flags. |
| * |
| * Inserting a NULL entry will store a reserved entry (like xa_reserve()) |
| * if no entry is present. Inserting will fail if a reserved entry is |
| * present, even though loading from this index will return NULL. |
| * |
| * Context: Any context. Takes and releases the xa_lock. May sleep if |
| * the @gfp flags permit. |
| * Return: 0 if the store succeeded. -EBUSY if another entry was present. |
| * -ENOMEM if memory could not be allocated. |
| */ |
| static inline int __must_check xa_insert(struct xarray *xa, |
| unsigned long index, void *entry, gfp_t gfp) |
| { |
| int err; |
| |
| xa_lock(xa); |
| err = __xa_insert(xa, index, entry, gfp); |
| xa_unlock(xa); |
| |
| return err; |
| } |
| |
| /** |
| * xa_insert_bh() - Store this entry in the XArray unless another entry is |
| * already present. |
| * @xa: XArray. |
| * @index: Index into array. |
| * @entry: New entry. |
| * @gfp: Memory allocation flags. |
| * |
| * Inserting a NULL entry will store a reserved entry (like xa_reserve()) |
| * if no entry is present. Inserting will fail if a reserved entry is |
| * present, even though loading from this index will return NULL. |
| * |
| * Context: Any context. Takes and releases the xa_lock while |
| * disabling softirqs. May sleep if the @gfp flags permit. |
| * Return: 0 if the store succeeded. -EBUSY if another entry was present. |
| * -ENOMEM if memory could not be allocated. |
| */ |
| static inline int __must_check xa_insert_bh(struct xarray *xa, |
| unsigned long index, void *entry, gfp_t gfp) |
| { |
| int err; |
| |
| xa_lock_bh(xa); |
| err = __xa_insert(xa, index, entry, gfp); |
| xa_unlock_bh(xa); |
| |
| return err; |
| } |
| |
| /** |
| * xa_insert_irq() - Store this entry in the XArray unless another entry is |
| * already present. |
| * @xa: XArray. |
| * @index: Index into array. |
| * @entry: New entry. |
| * @gfp: Memory allocation flags. |
| * |
| * Inserting a NULL entry will store a reserved entry (like xa_reserve()) |
| * if no entry is present. Inserting will fail if a reserved entry is |
| * present, even though loading from this index will return NULL. |
| * |
| * Context: Process context. Takes and releases the xa_lock while |
| * disabling interrupts. May sleep if the @gfp flags permit. |
| * Return: 0 if the store succeeded. -EBUSY if another entry was present. |
| * -ENOMEM if memory could not be allocated. |
| */ |
| static inline int __must_check xa_insert_irq(struct xarray *xa, |
| unsigned long index, void *entry, gfp_t gfp) |
| { |
| int err; |
| |
| xa_lock_irq(xa); |
| err = __xa_insert(xa, index, entry, gfp); |
| xa_unlock_irq(xa); |
| |
| return err; |
| } |
| |
| /** |
| * xa_alloc() - Find somewhere to store this entry in the XArray. |
| * @xa: XArray. |
| * @id: Pointer to ID. |
| * @entry: New entry. |
| * @limit: Range of ID to allocate. |
| * @gfp: Memory allocation flags. |
| * |
| * Finds an empty entry in @xa between @limit.min and @limit.max, |
| * stores the index into the @id pointer, then stores the entry at |
| * that index. A concurrent lookup will not see an uninitialised @id. |
| * |
| * Context: Any context. Takes and releases the xa_lock. May sleep if |
| * the @gfp flags permit. |
| * Return: 0 on success, -ENOMEM if memory could not be allocated or |
| * -EBUSY if there are no free entries in @limit. |
| */ |
| static inline __must_check int xa_alloc(struct xarray *xa, u32 *id, |
| void *entry, struct xa_limit limit, gfp_t gfp) |
| { |
| int err; |
| |
| xa_lock(xa); |
| err = __xa_alloc(xa, id, entry, limit, gfp); |
| xa_unlock(xa); |
| |
| return err; |
| } |
| |
| /** |
| * xa_alloc_bh() - Find somewhere to store this entry in the XArray. |
| * @xa: XArray. |
| * @id: Pointer to ID. |
| * @entry: New entry. |
| * @limit: Range of ID to allocate. |
| * @gfp: Memory allocation flags. |
| * |
| * Finds an empty entry in @xa between @limit.min and @limit.max, |
| * stores the index into the @id pointer, then stores the entry at |
| * that index. A concurrent lookup will not see an uninitialised @id. |
| * |
| * Context: Any context. Takes and releases the xa_lock while |
| * disabling softirqs. May sleep if the @gfp flags permit. |
| * Return: 0 on success, -ENOMEM if memory could not be allocated or |
| * -EBUSY if there are no free entries in @limit. |
| */ |
| static inline int __must_check xa_alloc_bh(struct xarray *xa, u32 *id, |
| void *entry, struct xa_limit limit, gfp_t gfp) |
| { |
| int err; |
| |
| xa_lock_bh(xa); |
| err = __xa_alloc(xa, id, entry, limit, gfp); |
| xa_unlock_bh(xa); |
| |
| return err; |
| } |
| |
| /** |
| * xa_alloc_irq() - Find somewhere to store this entry in the XArray. |
| * @xa: XArray. |
| * @id: Pointer to ID. |
| * @entry: New entry. |
| * @limit: Range of ID to allocate. |
| * @gfp: Memory allocation flags. |
| * |
| * Finds an empty entry in @xa between @limit.min and @limit.max, |
| * stores the index into the @id pointer, then stores the entry at |
| * that index. A concurrent lookup will not see an uninitialised @id. |
| * |
| * Context: Process context. Takes and releases the xa_lock while |
| * disabling interrupts. May sleep if the @gfp flags permit. |
| * Return: 0 on success, -ENOMEM if memory could not be allocated or |
| * -EBUSY if there are no free entries in @limit. |
| */ |
| static inline int __must_check xa_alloc_irq(struct xarray *xa, u32 *id, |
| void *entry, struct xa_limit limit, gfp_t gfp) |
| { |
| int err; |
| |
| xa_lock_irq(xa); |
| err = __xa_alloc(xa, id, entry, limit, gfp); |
| xa_unlock_irq(xa); |
| |
| return err; |
| } |
| |
| /** |
| * xa_alloc_cyclic() - Find somewhere to store this entry in the XArray. |
| * @xa: XArray. |
| * @id: Pointer to ID. |
| * @entry: New entry. |
| * @limit: Range of allocated ID. |
| * @next: Pointer to next ID to allocate. |
| * @gfp: Memory allocation flags. |
| * |
| * Finds an empty entry in @xa between @limit.min and @limit.max, |
| * stores the index into the @id pointer, then stores the entry at |
| * that index. A concurrent lookup will not see an uninitialised @id. |
| * The search for an empty entry will start at @next and will wrap |
| * around if necessary. |
| * |
| * Context: Any context. Takes and releases the xa_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 or -EBUSY if there are no free entries in @limit. |
| */ |
| static inline int xa_alloc_cyclic(struct xarray *xa, u32 *id, void *entry, |
| struct xa_limit limit, u32 *next, gfp_t gfp) |
| { |
| int err; |
| |
| xa_lock(xa); |
| err = __xa_alloc_cyclic(xa, id, entry, limit, next, gfp); |
| xa_unlock(xa); |
| |
| return err; |
| } |
| |
| /** |
| * xa_alloc_cyclic_bh() - Find somewhere to store this entry in the XArray. |
| * @xa: XArray. |
| * @id: Pointer to ID. |
| * @entry: New entry. |
| * @limit: Range of allocated ID. |
| * @next: Pointer to next ID to allocate. |
| * @gfp: Memory allocation flags. |
| * |
| * Finds an empty entry in @xa between @limit.min and @limit.max, |
| * stores the index into the @id pointer, then stores the entry at |
| * that index. A concurrent lookup will not see an uninitialised @id. |
| * The search for an empty entry will start at @next and will wrap |
| * around if necessary. |
| * |
| * Context: Any context. Takes and releases the xa_lock while |
| * disabling softirqs. 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 or -EBUSY if there are no free entries in @limit. |
| */ |
| static inline int xa_alloc_cyclic_bh(struct xarray *xa, u32 *id, void *entry, |
| struct xa_limit limit, u32 *next, gfp_t gfp) |
| { |
| int err; |
| |
| xa_lock_bh(xa); |
| err = __xa_alloc_cyclic(xa, id, entry, limit, next, gfp); |
| xa_unlock_bh(xa); |
| |
| return err; |
| } |
| |
| /** |
| * xa_alloc_cyclic_irq() - Find somewhere to store this entry in the XArray. |
| * @xa: XArray. |
| * @id: Pointer to ID. |
| * @entry: New entry. |
| * @limit: Range of allocated ID. |
| * @next: Pointer to next ID to allocate. |
| * @gfp: Memory allocation flags. |
| * |
| * Finds an empty entry in @xa between @limit.min and @limit.max, |
| * stores the index into the @id pointer, then stores the entry at |
| * that index. A concurrent lookup will not see an uninitialised @id. |
| * The search for an empty entry will start at @next and will wrap |
| * around if necessary. |
| * |
| * Context: Process context. Takes and releases the xa_lock while |
| * disabling interrupts. 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 or -EBUSY if there are no free entries in @limit. |
| */ |
| static inline int xa_alloc_cyclic_irq(struct xarray *xa, u32 *id, void *entry, |
| struct xa_limit limit, u32 *next, gfp_t gfp) |
| { |
| int err; |
| |
| xa_lock_irq(xa); |
| err = __xa_alloc_cyclic(xa, id, entry, limit, next, gfp); |
| xa_unlock_irq(xa); |
| |
| return err; |
| } |
| |
| /** |
| * xa_reserve() - Reserve this index in the XArray. |
| * @xa: XArray. |
| * @index: Index into array. |
| * @gfp: Memory allocation flags. |
| * |
| * Ensures there is somewhere to store an entry at @index in the array. |
| * If there is already something stored at @index, this function does |
| * nothing. If there was nothing there, the entry is marked as reserved. |
| * Loading from a reserved entry returns a %NULL pointer. |
| * |
| * If you do not use the entry that you have reserved, call xa_release() |
| * or xa_erase() to free any unnecessary memory. |
| * |
| * Context: Any context. Takes and releases the xa_lock. |
| * May sleep if the @gfp flags permit. |
| * Return: 0 if the reservation succeeded or -ENOMEM if it failed. |
| */ |
| static inline __must_check |
| int xa_reserve(struct xarray *xa, unsigned long index, gfp_t gfp) |
| { |
| return xa_err(xa_cmpxchg(xa, index, NULL, XA_ZERO_ENTRY, gfp)); |
| } |
| |
| /** |
| * xa_reserve_bh() - Reserve this index in the XArray. |
| * @xa: XArray. |
| * @index: Index into array. |
| * @gfp: Memory allocation flags. |
| * |
| * A softirq-disabling version of xa_reserve(). |
| * |
| * Context: Any context. Takes and releases the xa_lock while |
| * disabling softirqs. |
| * Return: 0 if the reservation succeeded or -ENOMEM if it failed. |
| */ |
| static inline __must_check |
| int xa_reserve_bh(struct xarray *xa, unsigned long index, gfp_t gfp) |
| { |
| return xa_err(xa_cmpxchg_bh(xa, index, NULL, XA_ZERO_ENTRY, gfp)); |
| } |
| |
| /** |
| * xa_reserve_irq() - Reserve this index in the XArray. |
| * @xa: XArray. |
| * @index: Index into array. |
| * @gfp: Memory allocation flags. |
| * |
| * An interrupt-disabling version of xa_reserve(). |
| * |
| * Context: Process context. Takes and releases the xa_lock while |
| * disabling interrupts. |
| * Return: 0 if the reservation succeeded or -ENOMEM if it failed. |
| */ |
| static inline __must_check |
| int xa_reserve_irq(struct xarray *xa, unsigned long index, gfp_t gfp) |
| { |
| return xa_err(xa_cmpxchg_irq(xa, index, NULL, XA_ZERO_ENTRY, gfp)); |
| } |
| |
| /** |
| * xa_release() - Release a reserved entry. |
| * @xa: XArray. |
| * @index: Index of entry. |
| * |
| * After calling xa_reserve(), you can call this function to release the |
| * reservation. If the entry at @index has been stored to, this function |
| * will do nothing. |
| */ |
| static inline void xa_release(struct xarray *xa, unsigned long index) |
| { |
| xa_cmpxchg(xa, index, XA_ZERO_ENTRY, NULL, 0); |
| } |
| |
| /* Everything below here is the Advanced API. Proceed with caution. */ |
| |
| /* |
| * The xarray is constructed out of a set of 'chunks' of pointers. Choosing |
| * the best chunk size requires some tradeoffs. A power of two recommends |
| * itself so that we can walk the tree based purely on shifts and masks. |
| * Generally, the larger the better; as the number of slots per level of the |
| * tree increases, the less tall the tree needs to be. But that needs to be |
| * balanced against the memory consumption of each node. On a 64-bit system, |
| * xa_node is currently 576 bytes, and we get 7 of them per 4kB page. If we |
| * doubled the number of slots per node, we'd get only 3 nodes per 4kB page. |
| */ |
| #ifndef XA_CHUNK_SHIFT |
| #define XA_CHUNK_SHIFT (CONFIG_BASE_SMALL ? 4 : 6) |
| #endif |
| #define XA_CHUNK_SIZE (1UL << XA_CHUNK_SHIFT) |
| #define XA_CHUNK_MASK (XA_CHUNK_SIZE - 1) |
| #define XA_MAX_MARKS 3 |
| #define XA_MARK_LONGS DIV_ROUND_UP(XA_CHUNK_SIZE, BITS_PER_LONG) |
| |
| /* |
| * @count is the count of every non-NULL element in the ->slots array |
| * whether that is a value entry, a retry entry, a user pointer, |
| * a sibling entry or a pointer to the next level of the tree. |
| * @nr_values is the count of every element in ->slots which is |
| * either a value entry or a sibling of a value entry. |
| */ |
| struct xa_node { |
| unsigned char shift; /* Bits remaining in each slot */ |
| unsigned char offset; /* Slot offset in parent */ |
| unsigned char count; /* Total entry count */ |
| unsigned char nr_values; /* Value entry count */ |
| struct xa_node __rcu *parent; /* NULL at top of tree */ |
| struct xarray *array; /* The array we belong to */ |
| union { |
| struct list_head private_list; /* For tree user */ |
| struct rcu_head rcu_head; /* Used when freeing node */ |
| }; |
| void __rcu *slots[XA_CHUNK_SIZE]; |
| union { |
| unsigned long tags[XA_MAX_MARKS][XA_MARK_LONGS]; |
| unsigned long marks[XA_MAX_MARKS][XA_MARK_LONGS]; |
| }; |
| }; |
| |
| void xa_dump(const struct xarray *); |
| void xa_dump_node(const struct xa_node *); |
| |
| #ifdef XA_DEBUG |
| #define XA_BUG_ON(xa, x) do { \ |
| if (x) { \ |
| xa_dump(xa); \ |
| BUG(); \ |
| } \ |
| } while (0) |
| #define XA_NODE_BUG_ON(node, x) do { \ |
| if (x) { \ |
| if (node) xa_dump_node(node); \ |
| BUG(); \ |
| } \ |
| } while (0) |
| #else |
| #define XA_BUG_ON(xa, x) do { } while (0) |
| #define XA_NODE_BUG_ON(node, x) do { } while (0) |
| #endif |
| |
| /* Private */ |
| static inline void *xa_head(const struct xarray *xa) |
| { |
| return rcu_dereference_check(xa->xa_head, |
| lockdep_is_held(&xa->xa_lock)); |
| } |
| |
| /* Private */ |
| static inline void *xa_head_locked(const struct xarray *xa) |
| { |
| return rcu_dereference_protected(xa->xa_head, |
| lockdep_is_held(&xa->xa_lock)); |
| } |
| |
| /* Private */ |
| static inline void *xa_entry(const struct xarray *xa, |
| const struct xa_node *node, unsigned int offset) |
| { |
| XA_NODE_BUG_ON(node, offset >= XA_CHUNK_SIZE); |
| return rcu_dereference_check(node->slots[offset], |
| lockdep_is_held(&xa->xa_lock)); |
| } |
| |
| /* Private */ |
| static inline void *xa_entry_locked(const struct xarray *xa, |
| const struct xa_node *node, unsigned int offset) |
| { |
| XA_NODE_BUG_ON(node, offset >= XA_CHUNK_SIZE); |
| return rcu_dereference_protected(node->slots[offset], |
| lockdep_is_held(&xa->xa_lock)); |
| } |
| |
| /* Private */ |
| static inline struct xa_node *xa_parent(const struct xarray *xa, |
| const struct xa_node *node) |
| { |
| return rcu_dereference_check(node->parent, |
| lockdep_is_held(&xa->xa_lock)); |
| } |
| |
| /* Private */ |
| static inline struct xa_node *xa_parent_locked(const struct xarray *xa, |
| const struct xa_node *node) |
| { |
| return rcu_dereference_protected(node->parent, |
| lockdep_is_held(&xa->xa_lock)); |
| } |
| |
| /* Private */ |
| static inline void *xa_mk_node(const struct xa_node *node) |
| { |
| return (void *)((unsigned long)node | 2); |
| } |
| |
| /* Private */ |
| static inline struct xa_node *xa_to_node(const void *entry) |
| { |
| return (struct xa_node *)((unsigned long)entry - 2); |
| } |
| |
| /* Private */ |
| static inline bool xa_is_node(const void *entry) |
| { |
| return xa_is_internal(entry) && (unsigned long)entry > 4096; |
| } |
| |
| /* Private */ |
| static inline void *xa_mk_sibling(unsigned int offset) |
| { |
| return xa_mk_internal(offset); |
| } |
| |
| /* Private */ |
| static inline unsigned long xa_to_sibling(const void *entry) |
| { |
| return xa_to_internal(entry); |
| } |
| |
| /** |
| * xa_is_sibling() - Is the entry a sibling entry? |
| * @entry: Entry retrieved from the XArray |
| * |
| * Return: %true if the entry is a sibling entry. |
| */ |
| static inline bool xa_is_sibling(const void *entry) |
| { |
| return IS_ENABLED(CONFIG_XARRAY_MULTI) && xa_is_internal(entry) && |
| (entry < xa_mk_sibling(XA_CHUNK_SIZE - 1)); |
| } |
| |
| #define XA_RETRY_ENTRY xa_mk_internal(256) |
| |
| /** |
| * xa_is_retry() - Is the entry a retry entry? |
| * @entry: Entry retrieved from the XArray |
| * |
| * Return: %true if the entry is a retry entry. |
| */ |
| static inline bool xa_is_retry(const void *entry) |
| { |
| return unlikely(entry == XA_RETRY_ENTRY); |
| } |
| |
| /** |
| * xa_is_advanced() - Is the entry only permitted for the advanced API? |
| * @entry: Entry to be stored in the XArray. |
| * |
| * Return: %true if the entry cannot be stored by the normal API. |
| */ |
| static inline bool xa_is_advanced(const void *entry) |
| { |
| return xa_is_internal(entry) && (entry <= XA_RETRY_ENTRY); |
| } |
| |
| /** |
| * typedef xa_update_node_t - A callback function from the XArray. |
| * @node: The node which is being processed |
| * |
| * This function is called every time the XArray updates the count of |
| * present and value entries in a node. It allows advanced users to |
| * maintain the private_list in the node. |
| * |
| * Context: The xa_lock is held and interrupts may be disabled. |
| * Implementations should not drop the xa_lock, nor re-enable |
| * interrupts. |
| */ |
| typedef void (*xa_update_node_t)(struct xa_node *node); |
| |
| void xa_delete_node(struct xa_node *, xa_update_node_t); |
| |
| /* |
| * The xa_state is opaque to its users. It contains various different pieces |
| * of state involved in the current operation on the XArray. It should be |
| * declared on the stack and passed between the various internal routines. |
| * The various elements in it should not be accessed directly, but only |
| * through the provided accessor functions. The below documentation is for |
| * the benefit of those working on the code, not for users of the XArray. |
| * |
| * @xa_node usually points to the xa_node containing the slot we're operating |
| * on (and @xa_offset is the offset in the slots array). If there is a |
| * single entry in the array at index 0, there are no allocated xa_nodes to |
| * point to, and so we store %NULL in @xa_node. @xa_node is set to |
| * the value %XAS_RESTART if the xa_state is not walked to the correct |
| * position in the tree of nodes for this operation. If an error occurs |
| * during an operation, it is set to an %XAS_ERROR value. If we run off the |
| * end of the allocated nodes, it is set to %XAS_BOUNDS. |
| */ |
| struct xa_state { |
| struct xarray *xa; |
| unsigned long xa_index; |
| unsigned char xa_shift; |
| unsigned char xa_sibs; |
| unsigned char xa_offset; |
| unsigned char xa_pad; /* Helps gcc generate better code */ |
| struct xa_node *xa_node; |
| struct xa_node *xa_alloc; |
| xa_update_node_t xa_update; |
| }; |
| |
| /* |
| * We encode errnos in the xas->xa_node. If an error has happened, we need to |
| * drop the lock to fix it, and once we've done so the xa_state is invalid. |
| */ |
| #define XA_ERROR(errno) ((struct xa_node *)(((unsigned long)errno << 2) | 2UL)) |
| #define XAS_BOUNDS ((struct xa_node *)1UL) |
| #define XAS_RESTART ((struct xa_node *)3UL) |
| |
| #define __XA_STATE(array, index, shift, sibs) { \ |
| .xa = array, \ |
| .xa_index = index, \ |
| .xa_shift = shift, \ |
| .xa_sibs = sibs, \ |
| .xa_offset = 0, \ |
| .xa_pad = 0, \ |
| .xa_node = XAS_RESTART, \ |
| .xa_alloc = NULL, \ |
| .xa_update = NULL \ |
| } |
| |
| /** |
| * XA_STATE() - Declare an XArray operation state. |
| * @name: Name of this operation state (usually xas). |
| * @array: Array to operate on. |
| * @index: Initial index of interest. |
| * |
| * Declare and initialise an xa_state on the stack. |
| */ |
| #define XA_STATE(name, array, index) \ |
| struct xa_state name = __XA_STATE(array, index, 0, 0) |
| |
| /** |
| * XA_STATE_ORDER() - Declare an XArray operation state. |
| * @name: Name of this operation state (usually xas). |
| * @array: Array to operate on. |
| * @index: Initial index of interest. |
| * @order: Order of entry. |
| * |
| * Declare and initialise an xa_state on the stack. This variant of |
| * XA_STATE() allows you to specify the 'order' of the element you |
| * want to operate on.` |
| */ |
| #define XA_STATE_ORDER(name, array, index, order) \ |
| struct xa_state name = __XA_STATE(array, \ |
| (index >> order) << order, \ |
| order - (order % XA_CHUNK_SHIFT), \ |
| (1U << (order % XA_CHUNK_SHIFT)) - 1) |
| |
| #define xas_marked(xas, mark) xa_marked((xas)->xa, (mark)) |
| #define xas_trylock(xas) xa_trylock((xas)->xa) |
| #define xas_lock(xas) xa_lock((xas)->xa) |
| #define xas_unlock(xas) xa_unlock((xas)->xa) |
| #define xas_lock_bh(xas) xa_lock_bh((xas)->xa) |
| #define xas_unlock_bh(xas) xa_unlock_bh((xas)->xa) |
| #define xas_lock_irq(xas) xa_lock_irq((xas)->xa) |
| #define xas_unlock_irq(xas) xa_unlock_irq((xas)->xa) |
| #define xas_lock_irqsave(xas, flags) \ |
| xa_lock_irqsave((xas)->xa, flags) |
| #define xas_unlock_irqrestore(xas, flags) \ |
| xa_unlock_irqrestore((xas)->xa, flags) |
| |
| /** |
| * xas_error() - Return an errno stored in the xa_state. |
| * @xas: XArray operation state. |
| * |
| * Return: 0 if no error has been noted. A negative errno if one has. |
| */ |
| static inline int xas_error(const struct xa_state *xas) |
| { |
| return xa_err(xas->xa_node); |
| } |
| |
| /** |
| * xas_set_err() - Note an error in the xa_state. |
| * @xas: XArray operation state. |
| * @err: Negative error number. |
| * |
| * Only call this function with a negative @err; zero or positive errors |
| * will probably not behave the way you think they should. If you want |
| * to clear the error from an xa_state, use xas_reset(). |
| */ |
| static inline void xas_set_err(struct xa_state *xas, long err) |
| { |
| xas->xa_node = XA_ERROR(err); |
| } |
| |
| /** |
| * xas_invalid() - Is the xas in a retry or error state? |
| * @xas: XArray operation state. |
| * |
| * Return: %true if the xas cannot be used for operations. |
| */ |
| static inline bool xas_invalid(const struct xa_state *xas) |
| { |
| return (unsigned long)xas->xa_node & 3; |
| } |
| |
| /** |
| * xas_valid() - Is the xas a valid cursor into the array? |
| * @xas: XArray operation state. |
| * |
| * Return: %true if the xas can be used for operations. |
| */ |
| static inline bool xas_valid(const struct xa_state *xas) |
| { |
| return !xas_invalid(xas); |
| } |
| |
| /** |
| * xas_is_node() - Does the xas point to a node? |
| * @xas: XArray operation state. |
| * |
| * Return: %true if the xas currently references a node. |
| */ |
| static inline bool xas_is_node(const struct xa_state *xas) |
| { |
| return xas_valid(xas) && xas->xa_node; |
| } |
| |
| /* True if the pointer is something other than a node */ |
| static inline bool xas_not_node(struct xa_node *node) |
| { |
| return ((unsigned long)node & 3) || !node; |
| } |
| |
| /* True if the node represents RESTART or an error */ |
| static inline bool xas_frozen(struct xa_node *node) |
| { |
| return (unsigned long)node & 2; |
| } |
| |
| /* True if the node represents head-of-tree, RESTART or BOUNDS */ |
| static inline bool xas_top(struct xa_node *node) |
| { |
| return node <= XAS_RESTART; |
| } |
| |
| /** |
| * xas_reset() - Reset an XArray operation state. |
| * @xas: XArray operation state. |
| * |
| * Resets the error or walk state of the @xas so future walks of the |
| * array will start from the root. Use this if you have dropped the |
| * xarray lock and want to reuse the xa_state. |
| * |
| * Context: Any context. |
| */ |
| static inline void xas_reset(struct xa_state *xas) |
| { |
| xas->xa_node = XAS_RESTART; |
| } |
| |
| /** |
| * xas_retry() - Retry the operation if appropriate. |
| * @xas: XArray operation state. |
| * @entry: Entry from xarray. |
| * |
| * The advanced functions may sometimes return an internal entry, such as |
| * a retry entry or a zero entry. This function sets up the @xas to restart |
| * the walk from the head of the array if needed. |
| * |
| * Context: Any context. |
| * Return: true if the operation needs to be retried. |
| */ |
| static inline bool xas_retry(struct xa_state *xas, const void *entry) |
| { |
| if (xa_is_zero(entry)) |
| return true; |
| if (!xa_is_retry(entry)) |
| return false; |
| xas_reset(xas); |
| return true; |
| } |
| |
| void *xas_load(struct xa_state *); |
| void *xas_store(struct xa_state *, void *entry); |
| void *xas_find(struct xa_state *, unsigned long max); |
| void *xas_find_conflict(struct xa_state *); |
| |
| bool xas_get_mark(const struct xa_state *, xa_mark_t); |
| void xas_set_mark(const struct xa_state *, xa_mark_t); |
| void xas_clear_mark(const struct xa_state *, xa_mark_t); |
| void *xas_find_marked(struct xa_state *, unsigned long max, xa_mark_t); |
| void xas_init_marks(const struct xa_state *); |
| |
| bool xas_nomem(struct xa_state *, gfp_t); |
| void xas_pause(struct xa_state *); |
| |
| void xas_create_range(struct xa_state *); |
| |
| #ifdef CONFIG_XARRAY_MULTI |
| int xa_get_order(struct xarray *, unsigned long index); |
| void xas_split(struct xa_state *, void *entry, unsigned int order); |
| void xas_split_alloc(struct xa_state *, void *entry, unsigned int order, gfp_t); |
| #else |
| static inline int xa_get_order(struct xarray *xa, unsigned long index) |
| { |
| return 0; |
| } |
| |
| static inline void xas_split(struct xa_state *xas, void *entry, |
| unsigned int order) |
| { |
| xas_store(xas, entry); |
| } |
| |
| static inline void xas_split_alloc(struct xa_state *xas, void *entry, |
| unsigned int order, gfp_t gfp) |
| { |
| } |
| #endif |
| |
| /** |
| * xas_reload() - Refetch an entry from the xarray. |
| * @xas: XArray operation state. |
| * |
| * Use this function to check that a previously loaded entry still has |
| * the same value. This is useful for the lockless pagecache lookup where |
| * we walk the array with only the RCU lock to protect us, lock the page, |
| * then check that the page hasn't moved since we looked it up. |
| * |
| * The caller guarantees that @xas is still valid. If it may be in an |
| * error or restart state, call xas_load() instead. |
| * |
| * Return: The entry at this location in the xarray. |
| */ |
| static inline void *xas_reload(struct xa_state *xas) |
| { |
| struct xa_node *node = xas->xa_node; |
| void *entry; |
| char offset; |
| |
| if (!node) |
| return xa_head(xas->xa); |
| if (IS_ENABLED(CONFIG_XARRAY_MULTI)) { |
| offset = (xas->xa_index >> node->shift) & XA_CHUNK_MASK; |
| entry = xa_entry(xas->xa, node, offset); |
| if (!xa_is_sibling(entry)) |
| return entry; |
| offset = xa_to_sibling(entry); |
| } else { |
| offset = xas->xa_offset; |
| } |
| return xa_entry(xas->xa, node, offset); |
| } |
| |
| /** |
| * xas_set() - Set up XArray operation state for a different index. |
| * @xas: XArray operation state. |
| * @index: New index into the XArray. |
| * |
| * Move the operation state to refer to a different index. This will |
| * have the effect of starting a walk from the top; see xas_next() |
| * to move to an adjacent index. |
| */ |
| static inline void xas_set(struct xa_state *xas, unsigned long index) |
| { |
| xas->xa_index = index; |
| xas->xa_node = XAS_RESTART; |
| } |
| |
| /** |
| * xas_set_order() - Set up XArray operation state for a multislot entry. |
| * @xas: XArray operation state. |
| * @index: Target of the operation. |
| * @order: Entry occupies 2^@order indices. |
| */ |
| static inline void xas_set_order(struct xa_state *xas, unsigned long index, |
| unsigned int order) |
| { |
| #ifdef CONFIG_XARRAY_MULTI |
| xas->xa_index = order < BITS_PER_LONG ? (index >> order) << order : 0; |
| xas->xa_shift = order - (order % XA_CHUNK_SHIFT); |
| xas->xa_sibs = (1 << (order % XA_CHUNK_SHIFT)) - 1; |
| xas->xa_node = XAS_RESTART; |
| #else |
| BUG_ON(order > 0); |
| xas_set(xas, index); |
| #endif |
| } |
| |
| /** |
| * xas_set_update() - Set up XArray operation state for a callback. |
| * @xas: XArray operation state. |
| * @update: Function to call when updating a node. |
| * |
| * The XArray can notify a caller after it has updated an xa_node. |
| * This is advanced functionality and is only needed by the page cache. |
| */ |
| static inline void xas_set_update(struct xa_state *xas, xa_update_node_t update) |
| { |
| xas->xa_update = update; |
| } |
| |
| /** |
| * xas_next_entry() - Advance iterator to next present entry. |
| * @xas: XArray operation state. |
| * @max: Highest index to return. |
| * |
| * xas_next_entry() is an inline function to optimise xarray traversal for |
| * speed. It is equivalent to calling xas_find(), and will call xas_find() |
| * for all the hard cases. |
| * |
| * Return: The next present entry after the one currently referred to by @xas. |
| */ |
| static inline void *xas_next_entry(struct xa_state *xas, unsigned long max) |
| { |
| struct xa_node *node = xas->xa_node; |
| void *entry; |
| |
| if (unlikely(xas_not_node(node) || node->shift || |
| xas->xa_offset != (xas->xa_index & XA_CHUNK_MASK))) |
| return xas_find(xas, max); |
| |
| do { |
| if (unlikely(xas->xa_index >= max)) |
| return xas_find(xas, max); |
| if (unlikely(xas->xa_offset == XA_CHUNK_MASK)) |
| return xas_find(xas, max); |
| entry = xa_entry(xas->xa, node, xas->xa_offset + 1); |
| if (unlikely(xa_is_internal(entry))) |
| return xas_find(xas, max); |
| xas->xa_offset++; |
| xas->xa_index++; |
| } while (!entry); |
| |
| return entry; |
| } |
| |
| /* Private */ |
| static inline unsigned int xas_find_chunk(struct xa_state *xas, bool advance, |
| xa_mark_t mark) |
| { |
| unsigned long *addr = xas->xa_node->marks[(__force unsigned)mark]; |
| unsigned int offset = xas->xa_offset; |
| |
| if (advance) |
| offset++; |
| if (XA_CHUNK_SIZE == BITS_PER_LONG) { |
| if (offset < XA_CHUNK_SIZE) { |
| unsigned long data = *addr & (~0UL << offset); |
| if (data) |
| return __ffs(data); |
| } |
| return XA_CHUNK_SIZE; |
| } |
| |
| return find_next_bit(addr, XA_CHUNK_SIZE, offset); |
| } |
| |
| /** |
| * xas_next_marked() - Advance iterator to next marked entry. |
| * @xas: XArray operation state. |
| * @max: Highest index to return. |
| * @mark: Mark to search for. |
| * |
| * xas_next_marked() is an inline function to optimise xarray traversal for |
| * speed. It is equivalent to calling xas_find_marked(), and will call |
| * xas_find_marked() for all the hard cases. |
| * |
| * Return: The next marked entry after the one currently referred to by @xas. |
| */ |
| static inline void *xas_next_marked(struct xa_state *xas, unsigned long max, |
| xa_mark_t mark) |
| { |
| struct xa_node *node = xas->xa_node; |
| void *entry; |
| unsigned int offset; |
| |
| if (unlikely(xas_not_node(node) || node->shift)) |
| return xas_find_marked(xas, max, mark); |
| offset = xas_find_chunk(xas, true, mark); |
| xas->xa_offset = offset; |
| xas->xa_index = (xas->xa_index & ~XA_CHUNK_MASK) + offset; |
| if (xas->xa_index > max) |
| return NULL; |
| if (offset == XA_CHUNK_SIZE) |
| return xas_find_marked(xas, max, mark); |
| entry = xa_entry(xas->xa, node, offset); |
| if (!entry) |
| return xas_find_marked(xas, max, mark); |
| return entry; |
| } |
| |
| /* |
| * If iterating while holding a lock, drop the lock and reschedule |
| * every %XA_CHECK_SCHED loops. |
| */ |
| enum { |
| XA_CHECK_SCHED = 4096, |
| }; |
| |
| /** |
| * xas_for_each() - Iterate over a range of an XArray. |
| * @xas: XArray operation state. |
| * @entry: Entry retrieved from the array. |
| * @max: Maximum index to retrieve from array. |
| * |
| * The loop body will be executed for each entry present in the xarray |
| * between the current xas position and @max. @entry will be set to |
| * the entry retrieved from the xarray. It is safe to delete entries |
| * from the array in the loop body. You should hold either the RCU lock |
| * or the xa_lock while iterating. If you need to drop the lock, call |
| * xas_pause() first. |
| */ |
| #define xas_for_each(xas, entry, max) \ |
| for (entry = xas_find(xas, max); entry; \ |
| entry = xas_next_entry(xas, max)) |
| |
| /** |
| * xas_for_each_marked() - Iterate over a range of an XArray. |
| * @xas: XArray operation state. |
| * @entry: Entry retrieved from the array. |
| * @max: Maximum index to retrieve from array. |
| * @mark: Mark to search for. |
| * |
| * The loop body will be executed for each marked entry in the xarray |
| * between the current xas position and @max. @entry will be set to |
| * the entry retrieved from the xarray. It is safe to delete entries |
| * from the array in the loop body. You should hold either the RCU lock |
| * or the xa_lock while iterating. If you need to drop the lock, call |
| * xas_pause() first. |
| */ |
| #define xas_for_each_marked(xas, entry, max, mark) \ |
| for (entry = xas_find_marked(xas, max, mark); entry; \ |
| entry = xas_next_marked(xas, max, mark)) |
| |
| /** |
| * xas_for_each_conflict() - Iterate over a range of an XArray. |
| * @xas: XArray operation state. |
| * @entry: Entry retrieved from the array. |
| * |
| * The loop body will be executed for each entry in the XArray that |
| * lies within the range specified by @xas. If the loop terminates |
| * normally, @entry will be %NULL. The user may break out of the loop, |
| * which will leave @entry set to the conflicting entry. The caller |
| * may also call xa_set_err() to exit the loop while setting an error |
| * to record the reason. |
| */ |
| #define xas_for_each_conflict(xas, entry) \ |
| while ((entry = xas_find_conflict(xas))) |
| |
| void *__xas_next(struct xa_state *); |
| void *__xas_prev(struct xa_state *); |
| |
| /** |
| * xas_prev() - Move iterator to previous index. |
| * @xas: XArray operation state. |
| * |
| * If the @xas was in an error state, it will remain in an error state |
| * and this function will return %NULL. If the @xas has never been walked, |
| * it will have the effect of calling xas_load(). Otherwise one will be |
| * subtracted from the index and the state will be walked to the correct |
| * location in the array for the next operation. |
| * |
| * If the iterator was referencing index 0, this function wraps |
| * around to %ULONG_MAX. |
| * |
| * Return: The entry at the new index. This may be %NULL or an internal |
| * entry. |
| */ |
| static inline void *xas_prev(struct xa_state *xas) |
| { |
| struct xa_node *node = xas->xa_node; |
| |
| if (unlikely(xas_not_node(node) || node->shift || |
| xas->xa_offset == 0)) |
| return __xas_prev(xas); |
| |
| xas->xa_index--; |
| xas->xa_offset--; |
| return xa_entry(xas->xa, node, xas->xa_offset); |
| } |
| |
| /** |
| * xas_next() - Move state to next index. |
| * @xas: XArray operation state. |
| * |
| * If the @xas was in an error state, it will remain in an error state |
| * and this function will return %NULL. If the @xas has never been walked, |
| * it will have the effect of calling xas_load(). Otherwise one will be |
| * added to the index and the state will be walked to the correct |
| * location in the array for the next operation. |
| * |
| * If the iterator was referencing index %ULONG_MAX, this function wraps |
| * around to 0. |
| * |
| * Return: The entry at the new index. This may be %NULL or an internal |
| * entry. |
| */ |
| static inline void *xas_next(struct xa_state *xas) |
| { |
| struct xa_node *node = xas->xa_node; |
| |
| if (unlikely(xas_not_node(node) || node->shift || |
| xas->xa_offset == XA_CHUNK_MASK)) |
| return __xas_next(xas); |
| |
| xas->xa_index++; |
| xas->xa_offset++; |
| return xa_entry(xas->xa, node, xas->xa_offset); |
| } |
| |
| #endif /* _LINUX_XARRAY_H */ |