include/linux/idr.h

1 /* SPDX-License-Identifier: GPL-2.0-only */
5  * 2002-10-18  written by Jim Houston jim.houston@ccur.com
15 #include <linux/radix-tree.h>
42  * IDR_INIT() - Initialise an IDR.
45  * A freshly-initialised IDR contains no IDs.
50  * DEFINE_IDR() - Define a statically-allocated IDR.
59  * idr_get_cursor - Return the current position of the cyclic allocator
68 	return READ_ONCE(idr->idr_next);  in idr_get_cursor()
72  * idr_set_cursor - Set the current position of the cyclic allocator
81 	WRITE_ONCE(idr->idr_next, val);  in idr_set_cursor()
86  * idr synchronization (stolen from radix-tree.h)
90  * Other readers (lock-free or otherwise) and modifications may be running
94  * lifetimes of the items. So if RCU lock-free lookups are used, typically
96  * lock-free access; and that the items are freed by RCU (or only freed after
101 #define idr_lock(idr)		xa_lock(&(idr)->idr_rt)
102 #define idr_unlock(idr)		xa_unlock(&(idr)->idr_rt)
103 #define idr_lock_bh(idr)	xa_lock_bh(&(idr)->idr_rt)
104 #define idr_unlock_bh(idr)	xa_unlock_bh(&(idr)->idr_rt)
105 #define idr_lock_irq(idr)	xa_lock_irq(&(idr)->idr_rt)
106 #define idr_unlock_irq(idr)	xa_unlock_irq(&(idr)->idr_rt)
108 				xa_lock_irqsave(&(idr)->idr_rt, flags)
110 				xa_unlock_irqrestore(&(idr)->idr_rt, flags)
128  * idr_init_base() - Initialise an IDR.
137 	INIT_RADIX_TREE(&idr->idr_rt, IDR_RT_MARKER);  in idr_init_base()
138 	idr->idr_base = base;  in idr_init_base()
139 	idr->idr_next = 0;  in idr_init_base()
143  * idr_init() - Initialise an IDR.
155  * idr_is_empty() - Are there any IDs allocated?
162 	return radix_tree_empty(&idr->idr_rt) &&  in idr_is_empty()
163 		radix_tree_tagged(&idr->idr_rt, IDR_FREE);  in idr_is_empty()
167  * idr_preload_end - end preload section started with idr_preload()
178  * idr_for_each_entry() - Iterate over an IDR's elements of a given type.
184  * after normal termination @entry is left with the value NULL.  This
191  * idr_for_each_entry_ul() - Iterate over an IDR's elements of a given type.
198  * after normal termination @entry is left with the value NULL.  This
207  * idr_for_each_entry_continue() - Continue iteration over an IDR's elements of a given type
212  * Continue to iterate over entries, continuing after the current position.
220  * idr_for_each_entry_continue_ul() - Continue iteration over an IDR's elements of a given type
226  * Continue to iterate over entries, continuing after the current position.
227  * After normal termination @entry is left with the value NULL.  This
236  * IDA - ID Allocator, use when translation from id to pointer isn't necessary.
262  * ida_alloc() - Allocate an unused ID.
270  * Return: The allocated ID, or %-ENOMEM if memory could not be allocated,
271  * or %-ENOSPC if there are no free IDs.
279  * ida_alloc_min() - Allocate an unused ID.
288  * Return: The allocated ID, or %-ENOMEM if memory could not be allocated,
289  * or %-ENOSPC if there are no free IDs.
297  * ida_alloc_max() - Allocate an unused ID.
306  * Return: The allocated ID, or %-ENOMEM if memory could not be allocated,
307  * or %-ENOSPC if there are no free IDs.
316 	xa_init_flags(&ida->xa, IDA_INIT_FLAGS);  in ida_init()
324 			ida_alloc_range(ida, start, (end) - 1, gfp)
329 	return xa_empty(&ida->xa);  in ida_is_empty()