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- /* 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.
- * Two common ranges are predefined for you:
- * * xa_limit_32b - [0 - UINT_MAX]
- * * xa_limit_31b - [0 - INT_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)
- 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 */
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