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![Chris Mi](/assets/img/avatar_default.png)
The following new APIs are added: int idr_alloc_ext(struct idr *idr, void *ptr, unsigned long *index, unsigned long start, unsigned long end, gfp_t gfp); void *idr_remove_ext(struct idr *idr, unsigned long id); void *idr_find_ext(const struct idr *idr, unsigned long id); void *idr_replace_ext(struct idr *idr, void *ptr, unsigned long id); void *idr_get_next_ext(struct idr *idr, unsigned long *nextid); Signed-off-by: Chris Mi <chrism@mellanox.com> Signed-off-by: Jiri Pirko <jiri@mellanox.com> Signed-off-by: David S. Miller <davem@davemloft.net>
279 lines
7.8 KiB
C
279 lines
7.8 KiB
C
/*
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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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* Distributed under the GNU GPL license version 2.
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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_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 ((__force gfp_t)(3 << __GFP_BITS_SHIFT))
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#define IDR_INIT \
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{ \
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.idr_rt = RADIX_TREE_INIT(IDR_RT_MARKER) \
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}
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#define DEFINE_IDR(name) struct idr name = IDR_INIT
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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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void idr_preload(gfp_t gfp_mask);
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int idr_alloc_cmn(struct idr *idr, void *ptr, unsigned long *index,
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unsigned long start, unsigned long end, gfp_t gfp,
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bool ext);
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/**
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* idr_alloc - allocate an id
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* @idr: idr handle
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* @ptr: pointer to be associated with the new id
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* @start: the minimum id (inclusive)
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* @end: the maximum id (exclusive)
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* @gfp: memory allocation flags
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*
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* Allocates an unused ID in the range [start, end). Returns -ENOSPC
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* if there are no unused IDs in that range.
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*
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* Note that @end is treated as max when <= 0. This is to always allow
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* using @start + N as @end as long as N is inside integer range.
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*
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* Simultaneous modifications to the @idr are not allowed and should be
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* prevented by the user, usually with a lock. idr_alloc() may be called
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* concurrently with read-only accesses to the @idr, such as idr_find() and
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* idr_for_each_entry().
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*/
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static inline int idr_alloc(struct idr *idr, void *ptr,
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int start, int end, gfp_t gfp)
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{
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unsigned long id;
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int ret;
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if (WARN_ON_ONCE(start < 0))
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return -EINVAL;
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ret = idr_alloc_cmn(idr, ptr, &id, start, end, gfp, false);
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if (ret)
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return ret;
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return id;
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}
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static inline int idr_alloc_ext(struct idr *idr, void *ptr,
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unsigned long *index,
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unsigned long start,
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unsigned long end,
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gfp_t gfp)
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{
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return idr_alloc_cmn(idr, ptr, index, start, end, gfp, true);
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}
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int idr_alloc_cyclic(struct idr *, void *entry, int start, int end, gfp_t);
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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_ext(struct idr *idr, unsigned long *nextid);
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void *idr_replace(struct idr *, void *, int id);
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void *idr_replace_ext(struct idr *idr, void *ptr, unsigned long id);
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void idr_destroy(struct idr *);
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static inline void *idr_remove_ext(struct idr *idr, unsigned long id)
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{
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return radix_tree_delete_item(&idr->idr_rt, id, NULL);
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}
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static inline void *idr_remove(struct idr *idr, int id)
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{
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return idr_remove_ext(idr, id);
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}
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static inline void idr_init(struct idr *idr)
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{
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INIT_RADIX_TREE(&idr->idr_rt, IDR_RT_MARKER);
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idr->idr_next = 0;
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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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preempt_enable();
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}
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/**
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* idr_find - return pointer for given id
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* @idr: idr handle
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* @id: lookup key
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*
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* Return the pointer given the id it has been registered with. A %NULL
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* return indicates that @id is not valid or you passed %NULL in
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* idr_get_new().
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*
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* This function can be called under rcu_read_lock(), given that the leaf
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* pointers lifetimes are correctly managed.
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*/
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static inline void *idr_find_ext(const struct idr *idr, unsigned long id)
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{
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return radix_tree_lookup(&idr->idr_rt, id);
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}
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static inline void *idr_find(const struct idr *idr, int id)
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{
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return idr_find_ext(idr, id);
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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: id entry's key
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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 terminatinon @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)
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#define idr_for_each_entry_ext(idr, entry, id) \
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for (id = 0; ((entry) = idr_get_next_ext(idr, &(id))) != NULL; ++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 cursor
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* @id: id entry's key
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*
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* Continue to iterate over list of given type, continuing after
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* 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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* IDA - IDR based id allocator, use when translation from id to
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* 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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DECLARE_PER_CPU(struct ida_bitmap *, ida_bitmap);
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struct ida {
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struct radix_tree_root ida_rt;
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};
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#define IDA_INIT { \
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.ida_rt = RADIX_TREE_INIT(IDR_RT_MARKER | GFP_NOWAIT), \
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}
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#define DEFINE_IDA(name) struct ida name = IDA_INIT
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int ida_pre_get(struct ida *ida, gfp_t gfp_mask);
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int ida_get_new_above(struct ida *ida, int starting_id, int *p_id);
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void ida_remove(struct ida *ida, int id);
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void ida_destroy(struct ida *ida);
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int ida_simple_get(struct ida *ida, unsigned int start, unsigned int end,
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gfp_t gfp_mask);
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void ida_simple_remove(struct ida *ida, unsigned int id);
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static inline void ida_init(struct ida *ida)
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{
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INIT_RADIX_TREE(&ida->ida_rt, IDR_RT_MARKER | GFP_NOWAIT);
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}
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/**
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* ida_get_new - allocate new ID
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* @ida: idr handle
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* @p_id: pointer to the allocated handle
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*
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* Simple wrapper around ida_get_new_above() w/ @starting_id of zero.
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*/
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static inline int ida_get_new(struct ida *ida, int *p_id)
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{
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return ida_get_new_above(ida, 0, p_id);
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}
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static inline bool ida_is_empty(const struct ida *ida)
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{
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return radix_tree_empty(&ida->ida_rt);
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}
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#endif /* __IDR_H__ */
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