Reimplement IDR and IDA using the radix tree

#ifndef __IDR_H__

#define __IDR_H__

#include <linux/types.h>

#include <linux/bitops.h>

#include <linux/init.h>

#include <linux/rcupdate.h>

#include <linux/radix-tree.h>

#include <linux/gfp.h>

struct idr {

	struct radix_tree_root	idr_rt;

	unsigned int		idr_next;

};

/*

 * Using 6 bits at each layer allows us to allocate 7 layers out of each page.

 * 8 bits only gave us 3 layers out of every pair of pages, which is less

 * efficient except for trees with a largest element between 192-255 inclusive.

 * 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_BITS 6

#define IDR_SIZE (1 << IDR_BITS)

#define IDR_MASK ((1 << IDR_BITS)-1)

struct idr_layer {

	int			prefix;	/* the ID prefix of this idr_layer */

	int			layer;	/* distance from leaf */

	struct idr_layer __rcu	*ary[1<<IDR_BITS];

	int			count;	/* When zero, we can release it */

	union {

		/* A zero bit means "space here" */

		DECLARE_BITMAP(bitmap, IDR_SIZE);

		struct rcu_head		rcu_head;

	};

};

#define IDR_FREE	0

struct idr {

	struct idr_layer __rcu	*hint;	/* the last layer allocated from */

	struct idr_layer __rcu	*top;

	int			layers;	/* only valid w/o concurrent changes */

	int			cur;	/* current pos for cyclic allocation */

	spinlock_t		lock;

	int			id_free_cnt;

	struct idr_layer	*id_free;

};

/* Set the IDR flag and the IDR_FREE tag */

#define IDR_RT_MARKER		((__force gfp_t)(3 << __GFP_BITS_SHIFT))

#define IDR_INIT(name)							\

#define IDR_INIT							\

{									\

	.lock			= __SPIN_LOCK_UNLOCKED(name.lock),	\

	.idr_rt = RADIX_TREE_INIT(IDR_RT_MARKER)			\

}

#define DEFINE_IDR(name)	struct idr name = IDR_INIT(name)

#define DEFINE_IDR(name)	struct idr name = IDR_INIT

/**

 * idr_get_cursor - Return the current position of the cyclic allocator

 * idr_alloc_cyclic() if it is free (otherwise the search will start from

 * this position).

 */

static inline unsigned int idr_get_cursor(struct idr *idr)

static inline unsigned int idr_get_cursor(const struct idr *idr)

{

	return READ_ONCE(idr->cur);

	return READ_ONCE(idr->idr_next);

}

/**

 */

static inline void idr_set_cursor(struct idr *idr, unsigned int val)

{

	WRITE_ONCE(idr->cur, val);

	WRITE_ONCE(idr->idr_next, val);

}

/**

 * period).

 */

/*

 * This is what we export.

 */

void *idr_find_slowpath(struct idr *idp, int id);

void idr_preload(gfp_t gfp_mask);

int idr_alloc(struct idr *idp, void *ptr, int start, int end, gfp_t gfp_mask);

int idr_alloc_cyclic(struct idr *idr, void *ptr, int start, int end, gfp_t gfp_mask);

int idr_for_each(struct idr *idp,

int idr_alloc(struct idr *, void *entry, int start, int end, gfp_t);

int idr_alloc_cyclic(struct idr *, void *entry, int start, int end, gfp_t);

int idr_for_each(const struct idr *,

		 int (*fn)(int id, void *p, void *data), void *data);

void *idr_get_next(struct idr *idp, int *nextid);

void *idr_replace(struct idr *idp, void *ptr, int id);

void idr_remove(struct idr *idp, int id);

void idr_destroy(struct idr *idp);

void idr_init(struct idr *idp);

bool idr_is_empty(struct idr *idp);

void *idr_get_next(struct idr *, int *nextid);

void *idr_replace(struct idr *, void *, int id);

void idr_destroy(struct idr *);

static inline void idr_remove(struct idr *idr, int id)

{

	radix_tree_delete(&idr->idr_rt, id);

}

static inline void idr_init(struct idr *idr)

{

	INIT_RADIX_TREE(&idr->idr_rt, IDR_RT_MARKER);

	idr->idr_next = 0;

}

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()

 * This function can be called under rcu_read_lock(), given that the leaf

 * pointers lifetimes are correctly managed.

 */

static inline void *idr_find(struct idr *idr, int id)

static inline void *idr_find(const struct idr *idr, int id)

{

	struct idr_layer *hint = rcu_dereference_raw(idr->hint);

	if (hint && (id & ~IDR_MASK) == hint->prefix)

		return rcu_dereference_raw(hint->ary[id & IDR_MASK]);

	return idr_find_slowpath(idr, id);

	return radix_tree_lookup(&idr->idr_rt, id);

}

/**

 * idr_for_each_entry - iterate over an idr's elements of a given type

 * @idp:     idr handle

 * @idr:     idr handle

 * @entry:   the type * to use as cursor

 * @id:      id entry's key

 *

 * after normal terminatinon @entry is left with the value NULL.  This

 * is convenient for a "not found" value.

 */

#define idr_for_each_entry(idp, entry, id)			\

	for (id = 0; ((entry) = idr_get_next(idp, &(id))) != NULL; ++id)

#define idr_for_each_entry(idr, entry, id)			\

	for (id = 0; ((entry) = idr_get_next(idr, &(id))) != NULL; ++id)

/**

 * idr_for_each_entry - continue iteration over an idr's elements of a given type

 * @idp:     idr handle

 * 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 cursor

 * @id:      id entry's key

 *

 * Continue to iterate over list of given type, continuing after

 * the current position.

 */

#define idr_for_each_entry_continue(idp, entry, id)			\

	for ((entry) = idr_get_next((idp), &(id));			\

#define idr_for_each_entry_continue(idr, entry, id)			\

	for ((entry) = idr_get_next((idr), &(id));			\

	     entry;							\

	     ++id, (entry) = idr_get_next((idp), &(id)))

	     ++id, (entry) = idr_get_next((idr), &(id)))

/*

 * IDA - IDR based id allocator, use when translation from id to

 * pointer isn't necessary.

 *

 * IDA_BITMAP_LONGS is calculated to be one less to accommodate

 * ida_bitmap->nr_busy so that the whole struct fits in 128 bytes.

 */

#define IDA_CHUNK_SIZE		128	/* 128 bytes per chunk */

#define IDA_BITMAP_LONGS	(IDA_CHUNK_SIZE / sizeof(long) - 1)

#define IDA_BITMAP_LONGS	(IDA_CHUNK_SIZE / sizeof(long))

#define IDA_BITMAP_BITS 	(IDA_BITMAP_LONGS * sizeof(long) * 8)

struct ida_bitmap {

	long			nr_busy;

	unsigned long		bitmap[IDA_BITMAP_LONGS];

};

struct ida {

	struct idr		idr;

	struct radix_tree_root	ida_rt;

	struct ida_bitmap	*free_bitmap;

};

#define IDA_INIT(name)		{ .idr = IDR_INIT((name).idr), .free_bitmap = NULL, }

#define DEFINE_IDA(name)	struct ida name = IDA_INIT(name)

#define IDA_INIT	{						\

	.ida_rt = RADIX_TREE_INIT(IDR_RT_MARKER | GFP_NOWAIT),		\

}

#define DEFINE_IDA(name)	struct ida name = IDA_INIT

int ida_pre_get(struct ida *ida, gfp_t gfp_mask);

int ida_get_new_above(struct ida *ida, int starting_id, int *p_id);

void ida_remove(struct ida *ida, int id);

void ida_destroy(struct ida *ida);

void ida_init(struct ida *ida);

int ida_simple_get(struct ida *ida, unsigned int start, unsigned int end,

		   gfp_t gfp_mask);

void ida_simple_remove(struct ida *ida, unsigned int id);

static inline void ida_init(struct ida *ida)

{

	INIT_RADIX_TREE(&ida->ida_rt, IDR_RT_MARKER | GFP_NOWAIT);

	ida->free_bitmap = NULL;

}

/**

 * ida_get_new - allocate new ID

 * @ida:	idr handle

	return ida_get_new_above(ida, 0, p_id);

}

static inline bool ida_is_empty(struct ida *ida)

static inline bool ida_is_empty(const struct ida *ida)

{

	return idr_is_empty(&ida->idr);

	return radix_tree_empty(&ida->ida_rt);

}

void __init idr_init_cache(void);

#endif /* __IDR_H__ */

	unsigned long	tags[RADIX_TREE_MAX_TAGS][RADIX_TREE_TAG_LONGS];

};

/* root tags are stored in gfp_mask, shifted by __GFP_BITS_SHIFT */

/* The top bits of gfp_mask are used to store the root tags and the IDR flag */

#define ROOT_IS_IDR	((__force gfp_t)(1 << __GFP_BITS_SHIFT))

#define ROOT_TAG_SHIFT	(__GFP_BITS_SHIFT + 1)

struct radix_tree_root {

	gfp_t			gfp_mask;

	struct radix_tree_node	__rcu *rnode;

			unsigned new_order);

int radix_tree_join(struct radix_tree_root *, unsigned long index,

			unsigned new_order, void *);

void **idr_get_free(struct radix_tree_root *, struct radix_tree_iter *,

			gfp_t, int end);

#define RADIX_TREE_ITER_TAG_MASK	0x00FF	/* tag index in lower byte */

#define RADIX_TREE_ITER_TAGGED		0x0100	/* lookup tagged slots */

#define RADIX_TREE_ITER_CONTIG		0x0200	/* stop at first hole */

enum {

	RADIX_TREE_ITER_TAG_MASK = 0x0f,	/* tag index in lower nybble */

	RADIX_TREE_ITER_TAGGED   = 0x10,	/* lookup tagged slots */

	RADIX_TREE_ITER_CONTIG   = 0x20,	/* stop at first hole */

};

/**

 * radix_tree_iter_init - initialize radix tree iterator

void **radix_tree_next_chunk(const struct radix_tree_root *,

			     struct radix_tree_iter *iter, unsigned flags);

/**

 * radix_tree_iter_lookup - look up an index in the radix tree

 * @root: radix tree root

 * @iter: iterator state

 * @index: key to look up

 *

 * If @index is present in the radix tree, this function returns the slot

 * containing it and updates @iter to describe the entry.  If @index is not

 * present, it returns NULL.

 */

static inline void **radix_tree_iter_lookup(const struct radix_tree_root *root,

			struct radix_tree_iter *iter, unsigned long index)

{

	radix_tree_iter_init(iter, index);

	return radix_tree_next_chunk(root, iter, RADIX_TREE_ITER_CONTIG);

}

/**

 * radix_tree_iter_find - find a present entry

 * @root: radix tree root

 * @iter: iterator state

 * @index: start location

 *

 * This function returns the slot containing the entry with the lowest index

 * which is at least @index.  If @index is larger than any present entry, this

 * function returns NULL.  The @iter is updated to describe the entry found.

 */

static inline void **radix_tree_iter_find(const struct radix_tree_root *root,

			struct radix_tree_iter *iter, unsigned long index)

{

	radix_tree_iter_init(iter, index);

	return radix_tree_next_chunk(root, iter, 0);

}

/**

 * radix_tree_iter_retry - retry this chunk of the iteration

 * @iter:	iterator state

	if (WARN(!irqs_disabled(),

		 "Interrupts were enabled *very* early, fixing it\n"))

		local_irq_disable();

	idr_init_cache();

	radix_tree_init();

	/*

	 * Allow workqueue creation and work item queueing/cancelling

	trace_init();

	context_tracking_init();

	radix_tree_init();

	/* init some links before init_ISA_irqs() */

	early_irq_init();

	init_IRQ();