| /* 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__ */ |