330 lines
9.6 KiB
C
330 lines
9.6 KiB
C
/* SPDX-License-Identifier: GPL-2.0-only */
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/*
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* include/linux/idr.h
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*
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* 2002-10-18 written by Jim Houston jim.houston@ccur.com
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* Copyright (C) 2002 by Concurrent Computer Corporation
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*
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* Small id to pointer translation service avoiding fixed sized
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* tables.
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*/
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#ifndef __IDR_H__
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#define __IDR_H__
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#include <linux/radix-tree.h>
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#include <linux/gfp.h>
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#include <linux/percpu.h>
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struct idr {
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struct radix_tree_root idr_rt;
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unsigned int idr_base;
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unsigned int idr_next;
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};
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/*
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* The IDR API does not expose the tagging functionality of the radix tree
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* to users. Use tag 0 to track whether a node has free space below it.
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*/
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#define IDR_FREE 0
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/* Set the IDR flag and the IDR_FREE tag */
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#define IDR_RT_MARKER (ROOT_IS_IDR | (__force gfp_t) \
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(1 << (ROOT_TAG_SHIFT + IDR_FREE)))
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#define IDR_INIT_BASE(name, base) { \
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.idr_rt = RADIX_TREE_INIT(name, IDR_RT_MARKER), \
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.idr_base = (base), \
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.idr_next = 0, \
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}
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/**
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* IDR_INIT() - Initialise an IDR.
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* @name: Name of IDR.
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*
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* A freshly-initialised IDR contains no IDs.
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*/
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#define IDR_INIT(name) IDR_INIT_BASE(name, 0)
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/**
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* DEFINE_IDR() - Define a statically-allocated IDR.
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* @name: Name of IDR.
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*
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* An IDR defined using this macro is ready for use with no additional
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* initialisation required. It contains no IDs.
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*/
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#define DEFINE_IDR(name) struct idr name = IDR_INIT(name)
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/**
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* idr_get_cursor - Return the current position of the cyclic allocator
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* @idr: idr handle
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*
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* The value returned is the value that will be next returned from
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* idr_alloc_cyclic() if it is free (otherwise the search will start from
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* this position).
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*/
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static inline unsigned int idr_get_cursor(const struct idr *idr)
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{
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return READ_ONCE(idr->idr_next);
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}
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/**
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* idr_set_cursor - Set the current position of the cyclic allocator
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* @idr: idr handle
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* @val: new position
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*
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* The next call to idr_alloc_cyclic() will return @val if it is free
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* (otherwise the search will start from this position).
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*/
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static inline void idr_set_cursor(struct idr *idr, unsigned int val)
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{
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WRITE_ONCE(idr->idr_next, val);
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}
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/**
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* DOC: idr sync
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* idr synchronization (stolen from radix-tree.h)
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*
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* idr_find() is able to be called locklessly, using RCU. The caller must
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* ensure calls to this function are made within rcu_read_lock() regions.
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* Other readers (lock-free or otherwise) and modifications may be running
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* concurrently.
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*
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* It is still required that the caller manage the synchronization and
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* lifetimes of the items. So if RCU lock-free lookups are used, typically
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* this would mean that the items have their own locks, or are amenable to
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* lock-free access; and that the items are freed by RCU (or only freed after
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* having been deleted from the idr tree *and* a synchronize_rcu() grace
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* period).
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*/
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#define idr_lock(idr) xa_lock(&(idr)->idr_rt)
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#define idr_unlock(idr) xa_unlock(&(idr)->idr_rt)
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#define idr_lock_bh(idr) xa_lock_bh(&(idr)->idr_rt)
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#define idr_unlock_bh(idr) xa_unlock_bh(&(idr)->idr_rt)
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#define idr_lock_irq(idr) xa_lock_irq(&(idr)->idr_rt)
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#define idr_unlock_irq(idr) xa_unlock_irq(&(idr)->idr_rt)
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#define idr_lock_irqsave(idr, flags) \
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xa_lock_irqsave(&(idr)->idr_rt, flags)
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#define idr_unlock_irqrestore(idr, flags) \
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xa_unlock_irqrestore(&(idr)->idr_rt, flags)
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void idr_preload(gfp_t gfp_mask);
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int idr_alloc(struct idr *, void *ptr, int start, int end, gfp_t);
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int __must_check idr_alloc_u32(struct idr *, void *ptr, u32 *id,
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unsigned long max, gfp_t);
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int idr_alloc_cyclic(struct idr *, void *ptr, int start, int end, gfp_t);
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void *idr_remove(struct idr *, unsigned long id);
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void *idr_find(const struct idr *, unsigned long id);
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int idr_for_each(const struct idr *,
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int (*fn)(int id, void *p, void *data), void *data);
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void *idr_get_next(struct idr *, int *nextid);
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void *idr_get_next_ul(struct idr *, unsigned long *nextid);
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void *idr_replace(struct idr *, void *, unsigned long id);
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void idr_destroy(struct idr *);
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/**
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* idr_init_base() - Initialise an IDR.
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* @idr: IDR handle.
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* @base: The base value for the IDR.
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*
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* This variation of idr_init() creates an IDR which will allocate IDs
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* starting at %base.
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*/
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static inline void idr_init_base(struct idr *idr, int base)
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{
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INIT_RADIX_TREE(&idr->idr_rt, IDR_RT_MARKER);
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idr->idr_base = base;
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idr->idr_next = 0;
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}
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/**
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* idr_init() - Initialise an IDR.
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* @idr: IDR handle.
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*
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* Initialise a dynamically allocated IDR. To initialise a
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* statically allocated IDR, use DEFINE_IDR().
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*/
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static inline void idr_init(struct idr *idr)
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{
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idr_init_base(idr, 0);
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}
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/**
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* idr_is_empty() - Are there any IDs allocated?
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* @idr: IDR handle.
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*
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* Return: %true if any IDs have been allocated from this IDR.
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*/
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static inline bool idr_is_empty(const struct idr *idr)
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{
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return radix_tree_empty(&idr->idr_rt) &&
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radix_tree_tagged(&idr->idr_rt, IDR_FREE);
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}
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/**
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* idr_preload_end - end preload section started with idr_preload()
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*
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* Each idr_preload() should be matched with an invocation of this
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* function. See idr_preload() for details.
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*/
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static inline void idr_preload_end(void)
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{
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local_unlock(&radix_tree_preloads.lock);
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}
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/**
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* idr_for_each_entry() - Iterate over an IDR's elements of a given type.
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* @idr: IDR handle.
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* @entry: The type * to use as cursor
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* @id: Entry ID.
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*
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* @entry and @id do not need to be initialized before the loop, and
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* after normal termination @entry is left with the value NULL. This
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* is convenient for a "not found" value.
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*/
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#define idr_for_each_entry(idr, entry, id) \
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for (id = 0; ((entry) = idr_get_next(idr, &(id))) != NULL; id += 1U)
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/**
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* idr_for_each_entry_ul() - Iterate over an IDR's elements of a given type.
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* @idr: IDR handle.
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* @entry: The type * to use as cursor.
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* @tmp: A temporary placeholder for ID.
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* @id: Entry ID.
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*
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* @entry and @id do not need to be initialized before the loop, and
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* after normal termination @entry is left with the value NULL. This
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* is convenient for a "not found" value.
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*/
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#define idr_for_each_entry_ul(idr, entry, tmp, id) \
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for (tmp = 0, id = 0; \
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tmp <= id && ((entry) = idr_get_next_ul(idr, &(id))) != NULL; \
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tmp = id, ++id)
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/**
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* idr_for_each_entry_continue() - Continue iteration over an IDR's elements of a given type
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* @idr: IDR handle.
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* @entry: The type * to use as a cursor.
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* @id: Entry ID.
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*
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* Continue to iterate over entries, continuing after the current position.
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*/
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#define idr_for_each_entry_continue(idr, entry, id) \
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for ((entry) = idr_get_next((idr), &(id)); \
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entry; \
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++id, (entry) = idr_get_next((idr), &(id)))
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/**
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* idr_for_each_entry_continue_ul() - Continue iteration over an IDR's elements of a given type
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* @idr: IDR handle.
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* @entry: The type * to use as a cursor.
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* @tmp: A temporary placeholder for ID.
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* @id: Entry ID.
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*
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* Continue to iterate over entries, continuing after the current position.
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*/
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#define idr_for_each_entry_continue_ul(idr, entry, tmp, id) \
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for (tmp = id; \
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tmp <= id && ((entry) = idr_get_next_ul(idr, &(id))) != NULL; \
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tmp = id, ++id)
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/*
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* IDA - ID Allocator, use when translation from id to pointer isn't necessary.
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*/
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#define IDA_CHUNK_SIZE 128 /* 128 bytes per chunk */
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#define IDA_BITMAP_LONGS (IDA_CHUNK_SIZE / sizeof(long))
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#define IDA_BITMAP_BITS (IDA_BITMAP_LONGS * sizeof(long) * 8)
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struct ida_bitmap {
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unsigned long bitmap[IDA_BITMAP_LONGS];
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};
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struct ida {
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struct xarray xa;
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};
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#define IDA_INIT_FLAGS (XA_FLAGS_LOCK_IRQ | XA_FLAGS_ALLOC)
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#define IDA_INIT(name) { \
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.xa = XARRAY_INIT(name, IDA_INIT_FLAGS) \
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}
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#define DEFINE_IDA(name) struct ida name = IDA_INIT(name)
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int ida_alloc_range(struct ida *, unsigned int min, unsigned int max, gfp_t);
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void ida_free(struct ida *, unsigned int id);
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void ida_destroy(struct ida *ida);
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/**
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* ida_alloc() - Allocate an unused ID.
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* @ida: IDA handle.
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* @gfp: Memory allocation flags.
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*
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* Allocate an ID between 0 and %INT_MAX, inclusive.
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*
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* Context: Any context. It is safe to call this function without
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* locking in your code.
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* Return: The allocated ID, or %-ENOMEM if memory could not be allocated,
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* or %-ENOSPC if there are no free IDs.
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*/
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static inline int ida_alloc(struct ida *ida, gfp_t gfp)
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{
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return ida_alloc_range(ida, 0, ~0, gfp);
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}
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/**
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* ida_alloc_min() - Allocate an unused ID.
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* @ida: IDA handle.
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* @min: Lowest ID to allocate.
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* @gfp: Memory allocation flags.
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*
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* Allocate an ID between @min and %INT_MAX, inclusive.
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*
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* Context: Any context. It is safe to call this function without
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* locking in your code.
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* Return: The allocated ID, or %-ENOMEM if memory could not be allocated,
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* or %-ENOSPC if there are no free IDs.
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*/
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static inline int ida_alloc_min(struct ida *ida, unsigned int min, gfp_t gfp)
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{
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return ida_alloc_range(ida, min, ~0, gfp);
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}
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/**
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* ida_alloc_max() - Allocate an unused ID.
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* @ida: IDA handle.
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* @max: Highest ID to allocate.
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* @gfp: Memory allocation flags.
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*
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* Allocate an ID between 0 and @max, inclusive.
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*
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* Context: Any context. It is safe to call this function without
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* locking in your code.
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* Return: The allocated ID, or %-ENOMEM if memory could not be allocated,
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* or %-ENOSPC if there are no free IDs.
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*/
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static inline int ida_alloc_max(struct ida *ida, unsigned int max, gfp_t gfp)
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{
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return ida_alloc_range(ida, 0, max, gfp);
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}
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static inline void ida_init(struct ida *ida)
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{
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xa_init_flags(&ida->xa, IDA_INIT_FLAGS);
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}
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/*
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* ida_simple_get() and ida_simple_remove() are deprecated. Use
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* ida_alloc() and ida_free() instead respectively.
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*/
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#define ida_simple_get(ida, start, end, gfp) \
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ida_alloc_range(ida, start, (end) - 1, gfp)
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#define ida_simple_remove(ida, id) ida_free(ida, id)
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static inline bool ida_is_empty(const struct ida *ida)
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{
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return xa_empty(&ida->xa);
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}
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#endif /* __IDR_H__ */
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