include/linux/idr.h - third_party/kernel - Git at Google

 /* SPDX-License-Identifier: GPL-2.0-only */
 /*
  * include/linux/idr.h
  *
  * 2002-10-18  written by Jim Houston jim.houston@ccur.com
  *	Copyright (C) 2002 by Concurrent Computer Corporation
  *
  * Small id to pointer translation service avoiding fixed sized
  * tables.
  */

 #ifndef __IDR_H__
 #define __IDR_H__

 #include <linux/radix-tree.h>
 #include <linux/gfp.h>
 #include <linux/percpu.h>

 struct idr {
 	struct radix_tree_root	idr_rt;
 	unsigned int		idr_base;
 	unsigned int		idr_next;
 };

 /*
  * The IDR API does not expose the tagging functionality of the radix tree
  * to users.  Use tag 0 to track whether a node has free space below it.
  */
 #define IDR_FREE	0

 /* Set the IDR flag and the IDR_FREE tag */
 #define IDR_RT_MARKER	(ROOT_IS_IDR | (__force gfp_t)			\
 					(1 << (ROOT_TAG_SHIFT + IDR_FREE)))

 #define IDR_INIT_BASE(name, base) {					\
 	.idr_rt = RADIX_TREE_INIT(name, IDR_RT_MARKER),			\
 	.idr_base = (base),						\
 	.idr_next = 0,							\
 }

 /**
  * IDR_INIT() - Initialise an IDR.
  * @name: Name of IDR.
  *
  * A freshly-initialised IDR contains no IDs.
  */
 #define IDR_INIT(name)	IDR_INIT_BASE(name, 0)

 /**
  * DEFINE_IDR() - Define a statically-allocated IDR.
  * @name: Name of IDR.
  *
  * An IDR defined using this macro is ready for use with no additional
  * initialisation required.  It contains no IDs.
  */
 #define DEFINE_IDR(name)	struct idr name = IDR_INIT(name)

 /**
  * idr_get_cursor - Return the current position of the cyclic allocator
  * @idr: idr handle
  *
  * The value returned is the value that will be next returned from
  * idr_alloc_cyclic() if it is free (otherwise the search will start from
  * this position).
  */
 static inline unsigned int idr_get_cursor(const struct idr *idr)
 {
 	return READ_ONCE(idr->idr_next);
 }

 /**
  * idr_set_cursor - Set the current position of the cyclic allocator
  * @idr: idr handle
  * @val: new position
  *
  * The next call to idr_alloc_cyclic() will return @val if it is free
  * (otherwise the search will start from this position).
  */
 static inline void idr_set_cursor(struct idr *idr, unsigned int val)
 {
 	WRITE_ONCE(idr->idr_next, val);
 }

 /**
  * DOC: idr sync
  * idr synchronization (stolen from radix-tree.h)
  *
  * idr_find() is able to be called locklessly, using RCU. The caller must
  * ensure calls to this function are made within rcu_read_lock() regions.
  * Other readers (lock-free or otherwise) and modifications may be running
  * concurrently.
  *
  * It is still required that the caller manage the synchronization and
  * lifetimes of the items. So if RCU lock-free lookups are used, typically
  * this would mean that the items have their own locks, or are amenable to
  * lock-free access; and that the items are freed by RCU (or only freed after
  * having been deleted from the idr tree *and* a synchronize_rcu() grace
  * period).
  */

 #define idr_lock(idr)		xa_lock(&(idr)->idr_rt)
 #define idr_unlock(idr)		xa_unlock(&(idr)->idr_rt)
 #define idr_lock_bh(idr)	xa_lock_bh(&(idr)->idr_rt)
 #define idr_unlock_bh(idr)	xa_unlock_bh(&(idr)->idr_rt)
 #define idr_lock_irq(idr)	xa_lock_irq(&(idr)->idr_rt)
 #define idr_unlock_irq(idr)	xa_unlock_irq(&(idr)->idr_rt)
 #define idr_lock_irqsave(idr, flags) \
 				xa_lock_irqsave(&(idr)->idr_rt, flags)
 #define idr_unlock_irqrestore(idr, flags) \
 				xa_unlock_irqrestore(&(idr)->idr_rt, flags)

 void idr_preload(gfp_t gfp_mask);

 int idr_alloc(struct idr *, void *ptr, int start, int end, gfp_t);
 int __must_check idr_alloc_u32(struct idr *, void *ptr, u32 *id,
 				unsigned long max, gfp_t);
 int idr_alloc_cyclic(struct idr *, void *ptr, int start, int end, gfp_t);
 void *idr_remove(struct idr *, unsigned long id);
 void *idr_find(const struct idr *, unsigned long id);
 int idr_for_each(const struct idr *,
 		 int (*fn)(int id, void *p, void *data), void *data);
 void *idr_get_next(struct idr *, int *nextid);
 void *idr_get_next_ul(struct idr *, unsigned long *nextid);
 void *idr_replace(struct idr *, void *, unsigned long id);
 void idr_destroy(struct idr *);

 /**
  * idr_init_base() - Initialise an IDR.
  * @idr: IDR handle.
  * @base: The base value for the IDR.
  *
  * This variation of idr_init() creates an IDR which will allocate IDs
  * starting at %base.
  */
 static inline void idr_init_base(struct idr *idr, int base)
 {
 	INIT_RADIX_TREE(&idr->idr_rt, IDR_RT_MARKER);
 	idr->idr_base = base;
 	idr->idr_next = 0;
 }

 /**
  * idr_init() - Initialise an IDR.
  * @idr: IDR handle.
  *
  * Initialise a dynamically allocated IDR.  To initialise a
  * statically allocated IDR, use DEFINE_IDR().
  */
 static inline void idr_init(struct idr *idr)
 {
 	idr_init_base(idr, 0);
 }

 /**
  * idr_is_empty() - Are there any IDs allocated?
  * @idr: IDR handle.
  *
  * Return: %true if any IDs have been allocated from this IDR.
  */
 static inline bool idr_is_empty(const struct idr *idr)
 {
 	return radix_tree_empty(&idr->idr_rt) &&
 		radix_tree_tagged(&idr->idr_rt, IDR_FREE);
 }

 /**
  * idr_preload_end - end preload section started with idr_preload()
  *
  * Each idr_preload() should be matched with an invocation of this
  * function.  See idr_preload() for details.
  */
 static inline void idr_preload_end(void)
 {
 	local_unlock(&radix_tree_preloads.lock);
 }

 /**
  * idr_for_each_entry() - Iterate over an IDR's elements of a given type.
  * @idr: IDR handle.
  * @entry: The type * to use as cursor
  * @id: Entry ID.
  *
  * @entry and @id do not need to be initialized before the loop, and
  * after normal termination @entry is left with the value NULL.  This
  * is convenient for a "not found" value.
  */
 #define idr_for_each_entry(idr, entry, id)			\
 	for (id = 0; ((entry) = idr_get_next(idr, &(id))) != NULL; id += 1U)

 /**
  * idr_for_each_entry_ul() - Iterate over an IDR's elements of a given type.
  * @idr: IDR handle.
  * @entry: The type * to use as cursor.
  * @tmp: A temporary placeholder for ID.
  * @id: Entry ID.
  *
  * @entry and @id do not need to be initialized before the loop, and
  * after normal termination @entry is left with the value NULL.  This
  * is convenient for a "not found" value.
  */
 #define idr_for_each_entry_ul(idr, entry, tmp, id)			\
 	for (tmp = 0, id = 0;						\
 	     tmp <= id && ((entry) = idr_get_next_ul(idr, &(id))) != NULL; \
 	     tmp = id, ++id)

 /**
  * idr_for_each_entry_continue() - Continue iteration over an IDR's elements of a given type
  * @idr: IDR handle.
  * @entry: The type * to use as a cursor.
  * @id: Entry ID.
  *
  * Continue to iterate over entries, continuing after the current position.
  */
 #define idr_for_each_entry_continue(idr, entry, id)			\
 	for ((entry) = idr_get_next((idr), &(id));			\
 	     entry;							\
 	     ++id, (entry) = idr_get_next((idr), &(id)))

 /**
  * idr_for_each_entry_continue_ul() - Continue iteration over an IDR's elements of a given type
  * @idr: IDR handle.
  * @entry: The type * to use as a cursor.
  * @tmp: A temporary placeholder for ID.
  * @id: Entry ID.
  *
  * Continue to iterate over entries, continuing after the current position.
  */
 #define idr_for_each_entry_continue_ul(idr, entry, tmp, id)		\
 	for (tmp = id;							\
 	     tmp <= id && ((entry) = idr_get_next_ul(idr, &(id))) != NULL; \
 	     tmp = id, ++id)

 /*
  * IDA - ID Allocator, use when translation from id to pointer isn't necessary.
  */
 #define IDA_CHUNK_SIZE		128	/* 128 bytes per chunk */
 #define IDA_BITMAP_LONGS	(IDA_CHUNK_SIZE / sizeof(long))
 #define IDA_BITMAP_BITS 	(IDA_BITMAP_LONGS * sizeof(long) * 8)

 struct ida_bitmap {
 	unsigned long		bitmap[IDA_BITMAP_LONGS];
 };

 struct ida {
 	struct xarray xa;
 };

 #define IDA_INIT_FLAGS	(XA_FLAGS_LOCK_IRQ | XA_FLAGS_ALLOC)

 #define IDA_INIT(name)	{						\
 	.xa = XARRAY_INIT(name, IDA_INIT_FLAGS)				\
 }
 #define DEFINE_IDA(name)	struct ida name = IDA_INIT(name)

 int ida_alloc_range(struct ida *, unsigned int min, unsigned int max, gfp_t);
 void ida_free(struct ida *, unsigned int id);
 void ida_destroy(struct ida *ida);

 /**
  * ida_alloc() - Allocate an unused ID.
  * @ida: IDA handle.
  * @gfp: Memory allocation flags.
  *
  * Allocate an ID between 0 and %INT_MAX, inclusive.
  *
  * Context: Any context. It is safe to call this function without
  * locking in your code.
  * Return: The allocated ID, or %-ENOMEM if memory could not be allocated,
  * or %-ENOSPC if there are no free IDs.
  */
 static inline int ida_alloc(struct ida *ida, gfp_t gfp)
 {
 	return ida_alloc_range(ida, 0, ~0, gfp);
 }

 /**
  * ida_alloc_min() - Allocate an unused ID.
  * @ida: IDA handle.
  * @min: Lowest ID to allocate.
  * @gfp: Memory allocation flags.
  *
  * Allocate an ID between @min and %INT_MAX, inclusive.
  *
  * Context: Any context. It is safe to call this function without
  * locking in your code.
  * Return: The allocated ID, or %-ENOMEM if memory could not be allocated,
  * or %-ENOSPC if there are no free IDs.
  */
 static inline int ida_alloc_min(struct ida *ida, unsigned int min, gfp_t gfp)
 {
 	return ida_alloc_range(ida, min, ~0, gfp);
 }

 /**
  * ida_alloc_max() - Allocate an unused ID.
  * @ida: IDA handle.
  * @max: Highest ID to allocate.
  * @gfp: Memory allocation flags.
  *
  * Allocate an ID between 0 and @max, inclusive.
  *
  * Context: Any context. It is safe to call this function without
  * locking in your code.
  * Return: The allocated ID, or %-ENOMEM if memory could not be allocated,
  * or %-ENOSPC if there are no free IDs.
  */
 static inline int ida_alloc_max(struct ida *ida, unsigned int max, gfp_t gfp)
 {
 	return ida_alloc_range(ida, 0, max, gfp);
 }

 static inline void ida_init(struct ida *ida)
 {
 	xa_init_flags(&ida->xa, IDA_INIT_FLAGS);
 }

 /*
  * ida_simple_get() and ida_simple_remove() are deprecated. Use
  * ida_alloc() and ida_free() instead respectively.
  */
 #define ida_simple_get(ida, start, end, gfp)	\
 			ida_alloc_range(ida, start, (end) - 1, gfp)
 #define ida_simple_remove(ida, id)	ida_free(ida, id)

 static inline bool ida_is_empty(const struct ida *ida)
 {
 	return xa_empty(&ida->xa);
 }
 #endif /* __IDR_H__ */
	/* SPDX-License-Identifier: GPL-2.0-only */
	/*
	* include/linux/idr.h
	*
	* 2002-10-18 written by Jim Houston jim.houston@ccur.com
	* Copyright (C) 2002 by Concurrent Computer Corporation
	*
	* Small id to pointer translation service avoiding fixed sized
	* tables.
	*/

	#ifndef __IDR_H__
	#define __IDR_H__

	#include <linux/radix-tree.h>
	#include <linux/gfp.h>
	#include <linux/percpu.h>

	struct idr {
	struct radix_tree_root idr_rt;
	unsigned int idr_base;
	unsigned int idr_next;
	};

	/*
	* The IDR API does not expose the tagging functionality of the radix tree
	* to users. Use tag 0 to track whether a node has free space below it.
	*/
	#define IDR_FREE 0

	/* Set the IDR flag and the IDR_FREE tag */
	#define IDR_RT_MARKER (ROOT_IS_IDR \| (__force gfp_t) \
	(1 << (ROOT_TAG_SHIFT + IDR_FREE)))

	#define IDR_INIT_BASE(name, base) { \
	.idr_rt = RADIX_TREE_INIT(name, IDR_RT_MARKER), \
	.idr_base = (base), \
	.idr_next = 0, \
	}

	/**
	* IDR_INIT() - Initialise an IDR.
	* @name: Name of IDR.
	*
	* A freshly-initialised IDR contains no IDs.
	*/
	#define IDR_INIT(name) IDR_INIT_BASE(name, 0)

	/**
	* DEFINE_IDR() - Define a statically-allocated IDR.
	* @name: Name of IDR.
	*
	* An IDR defined using this macro is ready for use with no additional
	* initialisation required. It contains no IDs.
	*/
	#define DEFINE_IDR(name) struct idr name = IDR_INIT(name)

	/**
	* idr_get_cursor - Return the current position of the cyclic allocator
	* @idr: idr handle
	*
	* The value returned is the value that will be next returned from
	* idr_alloc_cyclic() if it is free (otherwise the search will start from
	* this position).
	*/
	static inline unsigned int idr_get_cursor(const struct idr *idr)
	{
	return READ_ONCE(idr->idr_next);
	}

	/**
	* idr_set_cursor - Set the current position of the cyclic allocator
	* @idr: idr handle
	* @val: new position
	*
	* The next call to idr_alloc_cyclic() will return @val if it is free
	* (otherwise the search will start from this position).
	*/
	static inline void idr_set_cursor(struct idr *idr, unsigned int val)
	{
	WRITE_ONCE(idr->idr_next, val);
	}

	/**
	* DOC: idr sync
	* idr synchronization (stolen from radix-tree.h)
	*
	* idr_find() is able to be called locklessly, using RCU. The caller must
	* ensure calls to this function are made within rcu_read_lock() regions.
	* Other readers (lock-free or otherwise) and modifications may be running
	* concurrently.
	*
	* It is still required that the caller manage the synchronization and
	* lifetimes of the items. So if RCU lock-free lookups are used, typically
	* this would mean that the items have their own locks, or are amenable to
	* lock-free access; and that the items are freed by RCU (or only freed after
	* having been deleted from the idr tree and a synchronize_rcu() grace
	* period).
	*/

	#define idr_lock(idr) xa_lock(&(idr)->idr_rt)
	#define idr_unlock(idr) xa_unlock(&(idr)->idr_rt)
	#define idr_lock_bh(idr) xa_lock_bh(&(idr)->idr_rt)
	#define idr_unlock_bh(idr) xa_unlock_bh(&(idr)->idr_rt)
	#define idr_lock_irq(idr) xa_lock_irq(&(idr)->idr_rt)
	#define idr_unlock_irq(idr) xa_unlock_irq(&(idr)->idr_rt)
	#define idr_lock_irqsave(idr, flags) \
	xa_lock_irqsave(&(idr)->idr_rt, flags)
	#define idr_unlock_irqrestore(idr, flags) \
	xa_unlock_irqrestore(&(idr)->idr_rt, flags)

	void idr_preload(gfp_t gfp_mask);

	int idr_alloc(struct idr , void ptr, int start, int end, gfp_t);
	int __must_check idr_alloc_u32(struct idr , void ptr, u32 *id,
	unsigned long max, gfp_t);
	int idr_alloc_cyclic(struct idr , void ptr, int start, int end, gfp_t);
	void idr_remove(struct idr , unsigned long id);
	void idr_find(const struct idr , unsigned long id);
	int idr_for_each(const struct idr *,
	int (fn)(int id, void p, void data), void data);
	void idr_get_next(struct idr , int *nextid);
	void idr_get_next_ul(struct idr , unsigned long *nextid);
	void idr_replace(struct idr , void *, unsigned long id);
	void idr_destroy(struct idr *);

	/**
	* idr_init_base() - Initialise an IDR.
	* @idr: IDR handle.
	* @base: The base value for the IDR.
	*
	* This variation of idr_init() creates an IDR which will allocate IDs
	* starting at %base.
	*/
	static inline void idr_init_base(struct idr *idr, int base)
	{
	INIT_RADIX_TREE(&idr->idr_rt, IDR_RT_MARKER);
	idr->idr_base = base;
	idr->idr_next = 0;
	}

	/**
	* idr_init() - Initialise an IDR.
	* @idr: IDR handle.
	*
	* Initialise a dynamically allocated IDR. To initialise a
	* statically allocated IDR, use DEFINE_IDR().
	*/
	static inline void idr_init(struct idr *idr)
	{
	idr_init_base(idr, 0);
	}

	/**
	* idr_is_empty() - Are there any IDs allocated?
	* @idr: IDR handle.
	*
	* Return: %true if any IDs have been allocated from this IDR.
	*/
	static inline bool idr_is_empty(const struct idr *idr)
	{
	return radix_tree_empty(&idr->idr_rt) &&
	radix_tree_tagged(&idr->idr_rt, IDR_FREE);
	}

	/**
	* idr_preload_end - end preload section started with idr_preload()
	*
	* Each idr_preload() should be matched with an invocation of this
	* function. See idr_preload() for details.
	*/
	static inline void idr_preload_end(void)
	{
	local_unlock(&radix_tree_preloads.lock);
	}

	/**
	* idr_for_each_entry() - Iterate over an IDR's elements of a given type.
	* @idr: IDR handle.
	* @entry: The type * to use as cursor
	* @id: Entry ID.
	*
	* @entry and @id do not need to be initialized before the loop, and
	* after normal termination @entry is left with the value NULL. This
	* is convenient for a "not found" value.
	*/
	#define idr_for_each_entry(idr, entry, id) \
	for (id = 0; ((entry) = idr_get_next(idr, &(id))) != NULL; id += 1U)

	/**
	* idr_for_each_entry_ul() - Iterate over an IDR's elements of a given type.
	* @idr: IDR handle.
	* @entry: The type * to use as cursor.
	* @tmp: A temporary placeholder for ID.
	* @id: Entry ID.
	*
	* @entry and @id do not need to be initialized before the loop, and
	* after normal termination @entry is left with the value NULL. This
	* is convenient for a "not found" value.
	*/
	#define idr_for_each_entry_ul(idr, entry, tmp, id) \
	for (tmp = 0, id = 0; \
	tmp <= id && ((entry) = idr_get_next_ul(idr, &(id))) != NULL; \
	tmp = id, ++id)

	/**
	* idr_for_each_entry_continue() - Continue iteration over an IDR's elements of a given type
	* @idr: IDR handle.
	* @entry: The type * to use as a cursor.
	* @id: Entry ID.
	*
	* Continue to iterate over entries, continuing after the current position.
	*/
	#define idr_for_each_entry_continue(idr, entry, id) \
	for ((entry) = idr_get_next((idr), &(id)); \
	entry; \
	++id, (entry) = idr_get_next((idr), &(id)))

	/**
	* idr_for_each_entry_continue_ul() - Continue iteration over an IDR's elements of a given type
	* @idr: IDR handle.
	* @entry: The type * to use as a cursor.
	* @tmp: A temporary placeholder for ID.
	* @id: Entry ID.
	*
	* Continue to iterate over entries, continuing after the current position.
	*/
	#define idr_for_each_entry_continue_ul(idr, entry, tmp, id) \
	for (tmp = id; \
	tmp <= id && ((entry) = idr_get_next_ul(idr, &(id))) != NULL; \
	tmp = id, ++id)

	/*
	* IDA - ID Allocator, use when translation from id to pointer isn't necessary.
	*/
	#define IDA_CHUNK_SIZE 128 /* 128 bytes per chunk */
	#define IDA_BITMAP_LONGS (IDA_CHUNK_SIZE / sizeof(long))
	#define IDA_BITMAP_BITS (IDA_BITMAP_LONGS * sizeof(long) * 8)

	struct ida_bitmap {
	unsigned long bitmap[IDA_BITMAP_LONGS];
	};

	struct ida {
	struct xarray xa;
	};

	#define IDA_INIT_FLAGS (XA_FLAGS_LOCK_IRQ \| XA_FLAGS_ALLOC)

	#define IDA_INIT(name) { \
	.xa = XARRAY_INIT(name, IDA_INIT_FLAGS) \
	}
	#define DEFINE_IDA(name) struct ida name = IDA_INIT(name)

	int ida_alloc_range(struct ida *, unsigned int min, unsigned int max, gfp_t);
	void ida_free(struct ida *, unsigned int id);
	void ida_destroy(struct ida *ida);

	/**
	* ida_alloc() - Allocate an unused ID.
	* @ida: IDA handle.
	* @gfp: Memory allocation flags.
	*
	* Allocate an ID between 0 and %INT_MAX, inclusive.
	*
	* Context: Any context. It is safe to call this function without
	* locking in your code.
	* Return: The allocated ID, or %-ENOMEM if memory could not be allocated,
	* or %-ENOSPC if there are no free IDs.
	*/
	static inline int ida_alloc(struct ida *ida, gfp_t gfp)
	{
	return ida_alloc_range(ida, 0, ~0, gfp);
	}

	/**
	* ida_alloc_min() - Allocate an unused ID.
	* @ida: IDA handle.
	* @min: Lowest ID to allocate.
	* @gfp: Memory allocation flags.
	*
	* Allocate an ID between @min and %INT_MAX, inclusive.
	*
	* Context: Any context. It is safe to call this function without
	* locking in your code.
	* Return: The allocated ID, or %-ENOMEM if memory could not be allocated,
	* or %-ENOSPC if there are no free IDs.
	*/
	static inline int ida_alloc_min(struct ida *ida, unsigned int min, gfp_t gfp)
	{
	return ida_alloc_range(ida, min, ~0, gfp);
	}

	/**
	* ida_alloc_max() - Allocate an unused ID.
	* @ida: IDA handle.
	* @max: Highest ID to allocate.
	* @gfp: Memory allocation flags.
	*
	* Allocate an ID between 0 and @max, inclusive.
	*
	* Context: Any context. It is safe to call this function without
	* locking in your code.
	* Return: The allocated ID, or %-ENOMEM if memory could not be allocated,
	* or %-ENOSPC if there are no free IDs.
	*/
	static inline int ida_alloc_max(struct ida *ida, unsigned int max, gfp_t gfp)
	{
	return ida_alloc_range(ida, 0, max, gfp);
	}

	static inline void ida_init(struct ida *ida)
	{
	xa_init_flags(&ida->xa, IDA_INIT_FLAGS);
	}

	/*
	* ida_simple_get() and ida_simple_remove() are deprecated. Use
	* ida_alloc() and ida_free() instead respectively.
	*/
	#define ida_simple_get(ida, start, end, gfp) \
	ida_alloc_range(ida, start, (end) - 1, gfp)
	#define ida_simple_remove(ida, id) ida_free(ida, id)

	static inline bool ida_is_empty(const struct ida *ida)
	{
	return xa_empty(&ida->xa);
	}
	#endif /* __IDR_H__ */