Current File : //usr/src/linux-headers-5.15.0-125-generic/include/linux/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)
{
preempt_enable();
}
/**
* 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; \
((entry) = tmp <= id ? idr_get_next_ul(idr, &(id)) : NULL) != 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.
* After normal termination @entry is left with the value NULL. This
* is convenient for a "not found" value.
*/
#define idr_for_each_entry_continue_ul(idr, entry, tmp, id) \
for (tmp = id; \
((entry) = tmp <= id ? idr_get_next_ul(idr, &(id)) : NULL) != 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__ */
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