2 * 2002-10-18 written by Jim Houston jim.houston@ccur.com
3 * Copyright (C) 2002 by Concurrent Computer Corporation
4 * Distributed under the GNU GPL license version 2.
6 * Modified by George Anzinger to reuse immediately and to use
7 * find bit instructions. Also removed _irq on spinlocks.
9 * Modified by Nadia Derbey to make it RCU safe.
11 * Small id to pointer translation service.
13 * It uses a radix tree like structure as a sparse array indexed
14 * by the id to obtain the pointer. The bitmap makes allocating
17 * You call it to allocate an id (an int) an associate with that id a
18 * pointer or what ever, we treat it as a (void *). You can pass this
19 * id to a user for him to pass back at a later time. You then pass
20 * that id to this code and it returns your pointer.
22 * You can release ids at any time. When all ids are released, most of
23 * the memory is returned (we keep MAX_IDR_FREE) in a local pool so we
24 * don't need to go to the memory "store" during an id allocate, just
25 * so you don't need to be too concerned about locking and conflicts
26 * with the slab allocator.
29 #ifndef TEST // to test in user space...
30 #include <linux/slab.h>
31 #include <linux/init.h>
32 #include <linux/export.h>
34 #include <linux/err.h>
35 #include <linux/string.h>
36 #include <linux/idr.h>
37 #include <linux/spinlock.h>
38 #include <linux/percpu.h>
39 #include <linux/hardirq.h>
41 static struct kmem_cache *idr_layer_cache;
42 static DEFINE_PER_CPU(struct idr_layer *, idr_preload_head);
43 static DEFINE_PER_CPU(int, idr_preload_cnt);
44 static DEFINE_SPINLOCK(simple_ida_lock);
46 static struct idr_layer *get_from_free_list(struct idr *idp)
51 spin_lock_irqsave(&idp->lock, flags);
52 if ((p = idp->id_free)) {
53 idp->id_free = p->ary[0];
57 spin_unlock_irqrestore(&idp->lock, flags);
62 * idr_layer_alloc - allocate a new idr_layer
63 * @gfp_mask: allocation mask
64 * @layer_idr: optional idr to allocate from
66 * If @layer_idr is %NULL, directly allocate one using @gfp_mask or fetch
67 * one from the per-cpu preload buffer. If @layer_idr is not %NULL, fetch
68 * an idr_layer from @idr->id_free.
70 * @layer_idr is to maintain backward compatibility with the old alloc
71 * interface - idr_pre_get() and idr_get_new*() - and will be removed
72 * together with per-pool preload buffer.
74 static struct idr_layer *idr_layer_alloc(gfp_t gfp_mask, struct idr *layer_idr)
76 struct idr_layer *new;
78 /* this is the old path, bypass to get_from_free_list() */
80 return get_from_free_list(layer_idr);
82 /* try to allocate directly from kmem_cache */
83 new = kmem_cache_zalloc(idr_layer_cache, gfp_mask);
88 * Try to fetch one from the per-cpu preload buffer if in process
89 * context. See idr_preload() for details.
95 new = __this_cpu_read(idr_preload_head);
97 __this_cpu_write(idr_preload_head, new->ary[0]);
98 __this_cpu_dec(idr_preload_cnt);
105 static void idr_layer_rcu_free(struct rcu_head *head)
107 struct idr_layer *layer;
109 layer = container_of(head, struct idr_layer, rcu_head);
110 kmem_cache_free(idr_layer_cache, layer);
113 static inline void free_layer(struct idr_layer *p)
115 call_rcu(&p->rcu_head, idr_layer_rcu_free);
118 /* only called when idp->lock is held */
119 static void __move_to_free_list(struct idr *idp, struct idr_layer *p)
121 p->ary[0] = idp->id_free;
126 static void move_to_free_list(struct idr *idp, struct idr_layer *p)
131 * Depends on the return element being zeroed.
133 spin_lock_irqsave(&idp->lock, flags);
134 __move_to_free_list(idp, p);
135 spin_unlock_irqrestore(&idp->lock, flags);
138 static void idr_mark_full(struct idr_layer **pa, int id)
140 struct idr_layer *p = pa[0];
143 __set_bit(id & IDR_MASK, &p->bitmap);
145 * If this layer is full mark the bit in the layer above to
146 * show that this part of the radix tree is full. This may
147 * complete the layer above and require walking up the radix
150 while (p->bitmap == IDR_FULL) {
154 __set_bit((id & IDR_MASK), &p->bitmap);
159 * idr_pre_get - reserve resources for idr allocation
161 * @gfp_mask: memory allocation flags
163 * This function should be called prior to calling the idr_get_new* functions.
164 * It preallocates enough memory to satisfy the worst possible allocation. The
165 * caller should pass in GFP_KERNEL if possible. This of course requires that
166 * no spinning locks be held.
168 * If the system is REALLY out of memory this function returns %0,
171 int idr_pre_get(struct idr *idp, gfp_t gfp_mask)
173 while (idp->id_free_cnt < MAX_IDR_FREE) {
174 struct idr_layer *new;
175 new = kmem_cache_zalloc(idr_layer_cache, gfp_mask);
178 move_to_free_list(idp, new);
182 EXPORT_SYMBOL(idr_pre_get);
185 * sub_alloc - try to allocate an id without growing the tree depth
187 * @starting_id: id to start search at
188 * @id: pointer to the allocated handle
189 * @pa: idr_layer[MAX_IDR_LEVEL] used as backtrack buffer
190 * @gfp_mask: allocation mask for idr_layer_alloc()
191 * @layer_idr: optional idr passed to idr_layer_alloc()
193 * Allocate an id in range [@starting_id, INT_MAX] from @idp without
194 * growing its depth. Returns
196 * the allocated id >= 0 if successful,
197 * -EAGAIN if the tree needs to grow for allocation to succeed,
198 * -ENOSPC if the id space is exhausted,
199 * -ENOMEM if more idr_layers need to be allocated.
201 static int sub_alloc(struct idr *idp, int *starting_id, struct idr_layer **pa,
202 gfp_t gfp_mask, struct idr *layer_idr)
205 struct idr_layer *p, *new;
216 * We run around this while until we reach the leaf node...
218 n = (id >> (IDR_BITS*l)) & IDR_MASK;
220 m = find_next_bit(&bm, IDR_SIZE, n);
222 /* no space available go back to previous layer. */
225 id = (id | ((1 << (IDR_BITS * l)) - 1)) + 1;
227 /* if already at the top layer, we need to grow */
228 if (id >= 1 << (idp->layers * IDR_BITS)) {
235 /* If we need to go up one layer, continue the
236 * loop; otherwise, restart from the top.
238 sh = IDR_BITS * (l + 1);
239 if (oid >> sh == id >> sh)
246 id = ((id >> sh) ^ n ^ m) << sh;
248 if ((id >= MAX_IDR_BIT) || (id < 0))
253 * Create the layer below if it is missing.
256 new = idr_layer_alloc(gfp_mask, layer_idr);
260 rcu_assign_pointer(p->ary[m], new);
271 static int idr_get_empty_slot(struct idr *idp, int starting_id,
272 struct idr_layer **pa, gfp_t gfp_mask,
273 struct idr *layer_idr)
275 struct idr_layer *p, *new;
282 layers = idp->layers;
284 if (!(p = idr_layer_alloc(gfp_mask, layer_idr)))
290 * Add a new layer to the top of the tree if the requested
291 * id is larger than the currently allocated space.
293 while ((layers < (MAX_IDR_LEVEL - 1)) && (id >= (1 << (layers*IDR_BITS)))) {
296 /* special case: if the tree is currently empty,
297 * then we grow the tree by moving the top node
303 if (!(new = idr_layer_alloc(gfp_mask, layer_idr))) {
305 * The allocation failed. If we built part of
306 * the structure tear it down.
308 spin_lock_irqsave(&idp->lock, flags);
309 for (new = p; p && p != idp->top; new = p) {
312 new->bitmap = new->count = 0;
313 __move_to_free_list(idp, new);
315 spin_unlock_irqrestore(&idp->lock, flags);
320 new->layer = layers-1;
321 if (p->bitmap == IDR_FULL)
322 __set_bit(0, &new->bitmap);
325 rcu_assign_pointer(idp->top, p);
326 idp->layers = layers;
327 v = sub_alloc(idp, &id, pa, gfp_mask, layer_idr);
334 * @id and @pa are from a successful allocation from idr_get_empty_slot().
335 * Install the user pointer @ptr and mark the slot full.
337 static void idr_fill_slot(void *ptr, int id, struct idr_layer **pa)
339 rcu_assign_pointer(pa[0]->ary[id & IDR_MASK], (struct idr_layer *)ptr);
341 idr_mark_full(pa, id);
345 * idr_get_new_above - allocate new idr entry above or equal to a start id
347 * @ptr: pointer you want associated with the id
348 * @starting_id: id to start search at
349 * @id: pointer to the allocated handle
351 * This is the allocate id function. It should be called with any
354 * If allocation from IDR's private freelist fails, idr_get_new_above() will
355 * return %-EAGAIN. The caller should retry the idr_pre_get() call to refill
356 * IDR's preallocation and then retry the idr_get_new_above() call.
358 * If the idr is full idr_get_new_above() will return %-ENOSPC.
360 * @id returns a value in the range @starting_id ... %0x7fffffff
362 int idr_get_new_above(struct idr *idp, void *ptr, int starting_id, int *id)
364 struct idr_layer *pa[MAX_IDR_LEVEL];
367 rv = idr_get_empty_slot(idp, starting_id, pa, 0, idp);
369 return rv == -ENOMEM ? -EAGAIN : rv;
371 idr_fill_slot(ptr, rv, pa);
375 EXPORT_SYMBOL(idr_get_new_above);
378 * idr_preload - preload for idr_alloc()
379 * @gfp_mask: allocation mask to use for preloading
381 * Preload per-cpu layer buffer for idr_alloc(). Can only be used from
382 * process context and each idr_preload() invocation should be matched with
383 * idr_preload_end(). Note that preemption is disabled while preloaded.
385 * The first idr_alloc() in the preloaded section can be treated as if it
386 * were invoked with @gfp_mask used for preloading. This allows using more
387 * permissive allocation masks for idrs protected by spinlocks.
389 * For example, if idr_alloc() below fails, the failure can be treated as
390 * if idr_alloc() were called with GFP_KERNEL rather than GFP_NOWAIT.
392 * idr_preload(GFP_KERNEL);
395 * id = idr_alloc(idr, ptr, start, end, GFP_NOWAIT);
402 void idr_preload(gfp_t gfp_mask)
405 * Consuming preload buffer from non-process context breaks preload
406 * allocation guarantee. Disallow usage from those contexts.
408 WARN_ON_ONCE(in_interrupt());
409 might_sleep_if(gfp_mask & __GFP_WAIT);
414 * idr_alloc() is likely to succeed w/o full idr_layer buffer and
415 * return value from idr_alloc() needs to be checked for failure
416 * anyway. Silently give up if allocation fails. The caller can
417 * treat failures from idr_alloc() as if idr_alloc() were called
418 * with @gfp_mask which should be enough.
420 while (__this_cpu_read(idr_preload_cnt) < MAX_IDR_FREE) {
421 struct idr_layer *new;
424 new = kmem_cache_zalloc(idr_layer_cache, gfp_mask);
429 /* link the new one to per-cpu preload list */
430 new->ary[0] = __this_cpu_read(idr_preload_head);
431 __this_cpu_write(idr_preload_head, new);
432 __this_cpu_inc(idr_preload_cnt);
435 EXPORT_SYMBOL(idr_preload);
438 * idr_alloc - allocate new idr entry
439 * @idr: the (initialized) idr
440 * @ptr: pointer to be associated with the new id
441 * @start: the minimum id (inclusive)
442 * @end: the maximum id (exclusive, <= 0 for max)
443 * @gfp_mask: memory allocation flags
445 * Allocate an id in [start, end) and associate it with @ptr. If no ID is
446 * available in the specified range, returns -ENOSPC. On memory allocation
447 * failure, returns -ENOMEM.
449 * Note that @end is treated as max when <= 0. This is to always allow
450 * using @start + N as @end as long as N is inside integer range.
452 * The user is responsible for exclusively synchronizing all operations
453 * which may modify @idr. However, read-only accesses such as idr_find()
454 * or iteration can be performed under RCU read lock provided the user
455 * destroys @ptr in RCU-safe way after removal from idr.
457 int idr_alloc(struct idr *idr, void *ptr, int start, int end, gfp_t gfp_mask)
459 int max = end > 0 ? end - 1 : INT_MAX; /* inclusive upper limit */
460 struct idr_layer *pa[MAX_IDR_LEVEL];
463 might_sleep_if(gfp_mask & __GFP_WAIT);
466 if (WARN_ON_ONCE(start < 0))
468 if (unlikely(max < start))
472 id = idr_get_empty_slot(idr, start, pa, gfp_mask, NULL);
473 if (unlikely(id < 0))
475 if (unlikely(id > max))
478 idr_fill_slot(ptr, id, pa);
481 EXPORT_SYMBOL_GPL(idr_alloc);
483 static void idr_remove_warning(int id)
486 "idr_remove called for id=%d which is not allocated.\n", id);
490 static void sub_remove(struct idr *idp, int shift, int id)
492 struct idr_layer *p = idp->top;
493 struct idr_layer **pa[MAX_IDR_LEVEL];
494 struct idr_layer ***paa = &pa[0];
495 struct idr_layer *to_free;
501 while ((shift > 0) && p) {
502 n = (id >> shift) & IDR_MASK;
503 __clear_bit(n, &p->bitmap);
509 if (likely(p != NULL && test_bit(n, &p->bitmap))){
510 __clear_bit(n, &p->bitmap);
511 rcu_assign_pointer(p->ary[n], NULL);
513 while(*paa && ! --((**paa)->count)){
524 idr_remove_warning(id);
528 * idr_remove - remove the given id and free its slot
532 void idr_remove(struct idr *idp, int id)
535 struct idr_layer *to_free;
537 /* Mask off upper bits we don't use for the search. */
540 sub_remove(idp, (idp->layers - 1) * IDR_BITS, id);
541 if (idp->top && idp->top->count == 1 && (idp->layers > 1) &&
544 * Single child at leftmost slot: we can shrink the tree.
545 * This level is not needed anymore since when layers are
546 * inserted, they are inserted at the top of the existing
550 p = idp->top->ary[0];
551 rcu_assign_pointer(idp->top, p);
553 to_free->bitmap = to_free->count = 0;
556 while (idp->id_free_cnt >= MAX_IDR_FREE) {
557 p = get_from_free_list(idp);
559 * Note: we don't call the rcu callback here, since the only
560 * layers that fall into the freelist are those that have been
563 kmem_cache_free(idr_layer_cache, p);
567 EXPORT_SYMBOL(idr_remove);
569 void __idr_remove_all(struct idr *idp)
574 struct idr_layer *pa[MAX_IDR_LEVEL];
575 struct idr_layer **paa = &pa[0];
577 n = idp->layers * IDR_BITS;
579 rcu_assign_pointer(idp->top, NULL);
584 while (n > IDR_BITS && p) {
587 p = p->ary[(id >> n) & IDR_MASK];
592 /* Get the highest bit that the above add changed from 0->1. */
593 while (n < fls(id ^ bt_mask)) {
602 EXPORT_SYMBOL(__idr_remove_all);
605 * idr_destroy - release all cached layers within an idr tree
608 * Free all id mappings and all idp_layers. After this function, @idp is
609 * completely unused and can be freed / recycled. The caller is
610 * responsible for ensuring that no one else accesses @idp during or after
613 * A typical clean-up sequence for objects stored in an idr tree will use
614 * idr_for_each() to free all objects, if necessay, then idr_destroy() to
615 * free up the id mappings and cached idr_layers.
617 void idr_destroy(struct idr *idp)
619 __idr_remove_all(idp);
621 while (idp->id_free_cnt) {
622 struct idr_layer *p = get_from_free_list(idp);
623 kmem_cache_free(idr_layer_cache, p);
626 EXPORT_SYMBOL(idr_destroy);
629 * idr_find - return pointer for given id
633 * Return the pointer given the id it has been registered with. A %NULL
634 * return indicates that @id is not valid or you passed %NULL in
637 * This function can be called under rcu_read_lock(), given that the leaf
638 * pointers lifetimes are correctly managed.
640 void *idr_find(struct idr *idp, int id)
645 p = rcu_dereference_raw(idp->top);
648 n = (p->layer+1) * IDR_BITS;
650 /* Mask off upper bits we don't use for the search. */
659 BUG_ON(n != p->layer*IDR_BITS);
660 p = rcu_dereference_raw(p->ary[(id >> n) & IDR_MASK]);
664 EXPORT_SYMBOL(idr_find);
667 * idr_for_each - iterate through all stored pointers
669 * @fn: function to be called for each pointer
670 * @data: data passed back to callback function
672 * Iterate over the pointers registered with the given idr. The
673 * callback function will be called for each pointer currently
674 * registered, passing the id, the pointer and the data pointer passed
675 * to this function. It is not safe to modify the idr tree while in
676 * the callback, so functions such as idr_get_new and idr_remove are
679 * We check the return of @fn each time. If it returns anything other
680 * than %0, we break out and return that value.
682 * The caller must serialize idr_for_each() vs idr_get_new() and idr_remove().
684 int idr_for_each(struct idr *idp,
685 int (*fn)(int id, void *p, void *data), void *data)
687 int n, id, max, error = 0;
689 struct idr_layer *pa[MAX_IDR_LEVEL];
690 struct idr_layer **paa = &pa[0];
692 n = idp->layers * IDR_BITS;
693 p = rcu_dereference_raw(idp->top);
701 p = rcu_dereference_raw(p->ary[(id >> n) & IDR_MASK]);
705 error = fn(id, (void *)p, data);
711 while (n < fls(id)) {
719 EXPORT_SYMBOL(idr_for_each);
722 * idr_get_next - lookup next object of id to given id.
724 * @nextidp: pointer to lookup key
726 * Returns pointer to registered object with id, which is next number to
727 * given id. After being looked up, *@nextidp will be updated for the next
730 * This function can be called under rcu_read_lock(), given that the leaf
731 * pointers lifetimes are correctly managed.
733 void *idr_get_next(struct idr *idp, int *nextidp)
735 struct idr_layer *p, *pa[MAX_IDR_LEVEL];
736 struct idr_layer **paa = &pa[0];
741 p = rcu_dereference_raw(idp->top);
744 n = (p->layer + 1) * IDR_BITS;
751 p = rcu_dereference_raw(p->ary[(id >> n) & IDR_MASK]);
760 * Proceed to the next layer at the current level. Unlike
761 * idr_for_each(), @id isn't guaranteed to be aligned to
762 * layer boundary at this point and adding 1 << n may
763 * incorrectly skip IDs. Make sure we jump to the
764 * beginning of the next layer using round_up().
766 id = round_up(id + 1, 1 << n);
767 while (n < fls(id)) {
774 EXPORT_SYMBOL(idr_get_next);
778 * idr_replace - replace pointer for given id
780 * @ptr: pointer you want associated with the id
783 * Replace the pointer registered with an id and return the old value.
784 * A %-ENOENT return indicates that @id was not found.
785 * A %-EINVAL return indicates that @id was not within valid constraints.
787 * The caller must serialize with writers.
789 void *idr_replace(struct idr *idp, void *ptr, int id)
792 struct idr_layer *p, *old_p;
796 return ERR_PTR(-EINVAL);
798 n = (p->layer+1) * IDR_BITS;
803 return ERR_PTR(-EINVAL);
806 while ((n > 0) && p) {
807 p = p->ary[(id >> n) & IDR_MASK];
812 if (unlikely(p == NULL || !test_bit(n, &p->bitmap)))
813 return ERR_PTR(-ENOENT);
816 rcu_assign_pointer(p->ary[n], ptr);
820 EXPORT_SYMBOL(idr_replace);
822 void __init idr_init_cache(void)
824 idr_layer_cache = kmem_cache_create("idr_layer_cache",
825 sizeof(struct idr_layer), 0, SLAB_PANIC, NULL);
829 * idr_init - initialize idr handle
832 * This function is use to set up the handle (@idp) that you will pass
833 * to the rest of the functions.
835 void idr_init(struct idr *idp)
837 memset(idp, 0, sizeof(struct idr));
838 spin_lock_init(&idp->lock);
840 EXPORT_SYMBOL(idr_init);
844 * DOC: IDA description
845 * IDA - IDR based ID allocator
847 * This is id allocator without id -> pointer translation. Memory
848 * usage is much lower than full blown idr because each id only
849 * occupies a bit. ida uses a custom leaf node which contains
850 * IDA_BITMAP_BITS slots.
852 * 2007-04-25 written by Tejun Heo <htejun@gmail.com>
855 static void free_bitmap(struct ida *ida, struct ida_bitmap *bitmap)
859 if (!ida->free_bitmap) {
860 spin_lock_irqsave(&ida->idr.lock, flags);
861 if (!ida->free_bitmap) {
862 ida->free_bitmap = bitmap;
865 spin_unlock_irqrestore(&ida->idr.lock, flags);
872 * ida_pre_get - reserve resources for ida allocation
874 * @gfp_mask: memory allocation flag
876 * This function should be called prior to locking and calling the
877 * following function. It preallocates enough memory to satisfy the
878 * worst possible allocation.
880 * If the system is REALLY out of memory this function returns %0,
883 int ida_pre_get(struct ida *ida, gfp_t gfp_mask)
885 /* allocate idr_layers */
886 if (!idr_pre_get(&ida->idr, gfp_mask))
889 /* allocate free_bitmap */
890 if (!ida->free_bitmap) {
891 struct ida_bitmap *bitmap;
893 bitmap = kmalloc(sizeof(struct ida_bitmap), gfp_mask);
897 free_bitmap(ida, bitmap);
902 EXPORT_SYMBOL(ida_pre_get);
905 * ida_get_new_above - allocate new ID above or equal to a start id
907 * @starting_id: id to start search at
908 * @p_id: pointer to the allocated handle
910 * Allocate new ID above or equal to @starting_id. It should be called
911 * with any required locks.
913 * If memory is required, it will return %-EAGAIN, you should unlock
914 * and go back to the ida_pre_get() call. If the ida is full, it will
917 * @p_id returns a value in the range @starting_id ... %0x7fffffff.
919 int ida_get_new_above(struct ida *ida, int starting_id, int *p_id)
921 struct idr_layer *pa[MAX_IDR_LEVEL];
922 struct ida_bitmap *bitmap;
924 int idr_id = starting_id / IDA_BITMAP_BITS;
925 int offset = starting_id % IDA_BITMAP_BITS;
929 /* get vacant slot */
930 t = idr_get_empty_slot(&ida->idr, idr_id, pa, 0, &ida->idr);
932 return t == -ENOMEM ? -EAGAIN : t;
934 if (t * IDA_BITMAP_BITS >= MAX_IDR_BIT)
941 /* if bitmap isn't there, create a new one */
942 bitmap = (void *)pa[0]->ary[idr_id & IDR_MASK];
944 spin_lock_irqsave(&ida->idr.lock, flags);
945 bitmap = ida->free_bitmap;
946 ida->free_bitmap = NULL;
947 spin_unlock_irqrestore(&ida->idr.lock, flags);
952 memset(bitmap, 0, sizeof(struct ida_bitmap));
953 rcu_assign_pointer(pa[0]->ary[idr_id & IDR_MASK],
958 /* lookup for empty slot */
959 t = find_next_zero_bit(bitmap->bitmap, IDA_BITMAP_BITS, offset);
960 if (t == IDA_BITMAP_BITS) {
961 /* no empty slot after offset, continue to the next chunk */
967 id = idr_id * IDA_BITMAP_BITS + t;
968 if (id >= MAX_IDR_BIT)
971 __set_bit(t, bitmap->bitmap);
972 if (++bitmap->nr_busy == IDA_BITMAP_BITS)
973 idr_mark_full(pa, idr_id);
977 /* Each leaf node can handle nearly a thousand slots and the
978 * whole idea of ida is to have small memory foot print.
979 * Throw away extra resources one by one after each successful
982 if (ida->idr.id_free_cnt || ida->free_bitmap) {
983 struct idr_layer *p = get_from_free_list(&ida->idr);
985 kmem_cache_free(idr_layer_cache, p);
990 EXPORT_SYMBOL(ida_get_new_above);
993 * ida_remove - remove the given ID
997 void ida_remove(struct ida *ida, int id)
999 struct idr_layer *p = ida->idr.top;
1000 int shift = (ida->idr.layers - 1) * IDR_BITS;
1001 int idr_id = id / IDA_BITMAP_BITS;
1002 int offset = id % IDA_BITMAP_BITS;
1004 struct ida_bitmap *bitmap;
1006 /* clear full bits while looking up the leaf idr_layer */
1007 while ((shift > 0) && p) {
1008 n = (idr_id >> shift) & IDR_MASK;
1009 __clear_bit(n, &p->bitmap);
1017 n = idr_id & IDR_MASK;
1018 __clear_bit(n, &p->bitmap);
1020 bitmap = (void *)p->ary[n];
1021 if (!test_bit(offset, bitmap->bitmap))
1024 /* update bitmap and remove it if empty */
1025 __clear_bit(offset, bitmap->bitmap);
1026 if (--bitmap->nr_busy == 0) {
1027 __set_bit(n, &p->bitmap); /* to please idr_remove() */
1028 idr_remove(&ida->idr, idr_id);
1029 free_bitmap(ida, bitmap);
1036 "ida_remove called for id=%d which is not allocated.\n", id);
1038 EXPORT_SYMBOL(ida_remove);
1041 * ida_destroy - release all cached layers within an ida tree
1044 void ida_destroy(struct ida *ida)
1046 idr_destroy(&ida->idr);
1047 kfree(ida->free_bitmap);
1049 EXPORT_SYMBOL(ida_destroy);
1052 * ida_simple_get - get a new id.
1053 * @ida: the (initialized) ida.
1054 * @start: the minimum id (inclusive, < 0x8000000)
1055 * @end: the maximum id (exclusive, < 0x8000000 or 0)
1056 * @gfp_mask: memory allocation flags
1058 * Allocates an id in the range start <= id < end, or returns -ENOSPC.
1059 * On memory allocation failure, returns -ENOMEM.
1061 * Use ida_simple_remove() to get rid of an id.
1063 int ida_simple_get(struct ida *ida, unsigned int start, unsigned int end,
1068 unsigned long flags;
1070 BUG_ON((int)start < 0);
1071 BUG_ON((int)end < 0);
1076 BUG_ON(end < start);
1081 if (!ida_pre_get(ida, gfp_mask))
1084 spin_lock_irqsave(&simple_ida_lock, flags);
1085 ret = ida_get_new_above(ida, start, &id);
1088 ida_remove(ida, id);
1094 spin_unlock_irqrestore(&simple_ida_lock, flags);
1096 if (unlikely(ret == -EAGAIN))
1101 EXPORT_SYMBOL(ida_simple_get);
1104 * ida_simple_remove - remove an allocated id.
1105 * @ida: the (initialized) ida.
1106 * @id: the id returned by ida_simple_get.
1108 void ida_simple_remove(struct ida *ida, unsigned int id)
1110 unsigned long flags;
1112 BUG_ON((int)id < 0);
1113 spin_lock_irqsave(&simple_ida_lock, flags);
1114 ida_remove(ida, id);
1115 spin_unlock_irqrestore(&simple_ida_lock, flags);
1117 EXPORT_SYMBOL(ida_simple_remove);
1120 * ida_init - initialize ida handle
1123 * This function is use to set up the handle (@ida) that you will pass
1124 * to the rest of the functions.
1126 void ida_init(struct ida *ida)
1128 memset(ida, 0, sizeof(struct ida));
1129 idr_init(&ida->idr);
1132 EXPORT_SYMBOL(ida_init);