X-Git-Url: http://ftp.safe.ca/?p=safe%2Fjmp%2Flinux-2.6;a=blobdiff_plain;f=lib%2Fidr.c;h=1cac726c44bc17cc6fa1a7b5ab6358279a0c9a5d;hp=7b5a59caa9891d74ebbec9e29fef35cd2ba7e3b0;hb=d5aa407f59f5b83d2c50ec88f5bf56d40f1f8978;hpb=7aae6dd80e265aa9402ed507caaff4a5dba55069 diff --git a/lib/idr.c b/lib/idr.c index 7b5a59c..1cac726 100644 --- a/lib/idr.c +++ b/lib/idr.c @@ -6,6 +6,8 @@ * Modified by George Anzinger to reuse immediately and to use * find bit instructions. Also removed _irq on spinlocks. * + * Modified by Nadia Derbey to make it RCU safe. + * * Small id to pointer translation service. * * It uses a radix tree like structure as a sparse array indexed @@ -35,7 +37,7 @@ static struct kmem_cache *idr_layer_cache; -static struct idr_layer *alloc_layer(struct idr *idp) +static struct idr_layer *get_from_free_list(struct idr *idp) { struct idr_layer *p; unsigned long flags; @@ -50,15 +52,28 @@ static struct idr_layer *alloc_layer(struct idr *idp) return(p); } +static void idr_layer_rcu_free(struct rcu_head *head) +{ + struct idr_layer *layer; + + layer = container_of(head, struct idr_layer, rcu_head); + kmem_cache_free(idr_layer_cache, layer); +} + +static inline void free_layer(struct idr_layer *p) +{ + call_rcu(&p->rcu_head, idr_layer_rcu_free); +} + /* only called when idp->lock is held */ -static void __free_layer(struct idr *idp, struct idr_layer *p) +static void __move_to_free_list(struct idr *idp, struct idr_layer *p) { p->ary[0] = idp->id_free; idp->id_free = p; idp->id_free_cnt++; } -static void free_layer(struct idr *idp, struct idr_layer *p) +static void move_to_free_list(struct idr *idp, struct idr_layer *p) { unsigned long flags; @@ -66,17 +81,37 @@ static void free_layer(struct idr *idp, struct idr_layer *p) * Depends on the return element being zeroed. */ spin_lock_irqsave(&idp->lock, flags); - __free_layer(idp, p); + __move_to_free_list(idp, p); spin_unlock_irqrestore(&idp->lock, flags); } +static void idr_mark_full(struct idr_layer **pa, int id) +{ + struct idr_layer *p = pa[0]; + int l = 0; + + __set_bit(id & IDR_MASK, &p->bitmap); + /* + * If this layer is full mark the bit in the layer above to + * show that this part of the radix tree is full. This may + * complete the layer above and require walking up the radix + * tree. + */ + while (p->bitmap == IDR_FULL) { + if (!(p = pa[++l])) + break; + id = id >> IDR_BITS; + __set_bit((id & IDR_MASK), &p->bitmap); + } +} + /** * idr_pre_get - reserver resources for idr allocation * @idp: idr handle * @gfp_mask: memory allocation flags * * This function should be called prior to locking and calling the - * following function. It preallocates enough memory to satisfy + * idr_get_new* functions. It preallocates enough memory to satisfy * the worst possible allocation. * * If the system is REALLY out of memory this function returns 0, @@ -86,22 +121,21 @@ int idr_pre_get(struct idr *idp, gfp_t gfp_mask) { while (idp->id_free_cnt < IDR_FREE_MAX) { struct idr_layer *new; - new = kmem_cache_alloc(idr_layer_cache, gfp_mask); + new = kmem_cache_zalloc(idr_layer_cache, gfp_mask); if (new == NULL) return (0); - free_layer(idp, new); + move_to_free_list(idp, new); } return 1; } EXPORT_SYMBOL(idr_pre_get); -static int sub_alloc(struct idr *idp, void *ptr, int *starting_id) +static int sub_alloc(struct idr *idp, int *starting_id, struct idr_layer **pa) { int n, m, sh; struct idr_layer *p, *new; - struct idr_layer *pa[MAX_LEVEL]; int l, id, oid; - long bm; + unsigned long bm; id = *starting_id; restart: @@ -124,7 +158,7 @@ static int sub_alloc(struct idr *idp, void *ptr, int *starting_id) /* if already at the top layer, we need to grow */ if (!(p = pa[l])) { *starting_id = id; - return -2; + return IDR_NEED_TO_GROW; } /* If we need to go up one layer, continue the @@ -141,45 +175,30 @@ static int sub_alloc(struct idr *idp, void *ptr, int *starting_id) id = ((id >> sh) ^ n ^ m) << sh; } if ((id >= MAX_ID_BIT) || (id < 0)) - return -3; + return IDR_NOMORE_SPACE; if (l == 0) break; /* * Create the layer below if it is missing. */ if (!p->ary[m]) { - if (!(new = alloc_layer(idp))) + new = get_from_free_list(idp); + if (!new) return -1; - p->ary[m] = new; + new->layer = l-1; + rcu_assign_pointer(p->ary[m], new); p->count++; } pa[l--] = p; p = p->ary[m]; } - /* - * We have reached the leaf node, plant the - * users pointer and return the raw id. - */ - p->ary[m] = (struct idr_layer *)ptr; - __set_bit(m, &p->bitmap); - p->count++; - /* - * If this layer is full mark the bit in the layer above - * to show that this part of the radix tree is full. - * This may complete the layer above and require walking - * up the radix tree. - */ - n = id; - while (p->bitmap == IDR_FULL) { - if (!(p = pa[++l])) - break; - n = n >> IDR_BITS; - __set_bit((n & IDR_MASK), &p->bitmap); - } - return(id); + + pa[l] = p; + return id; } -static int idr_get_new_above_int(struct idr *idp, void *ptr, int starting_id) +static int idr_get_empty_slot(struct idr *idp, int starting_id, + struct idr_layer **pa) { struct idr_layer *p, *new; int layers, v, id; @@ -190,8 +209,9 @@ build_up: p = idp->top; layers = idp->layers; if (unlikely(!p)) { - if (!(p = alloc_layer(idp))) + if (!(p = get_from_free_list(idp))) return -1; + p->layer = 0; layers = 1; } /* @@ -200,9 +220,15 @@ build_up: */ while ((layers < (MAX_LEVEL - 1)) && (id >= (1 << (layers*IDR_BITS)))) { layers++; - if (!p->count) + if (!p->count) { + /* special case: if the tree is currently empty, + * then we grow the tree by moving the top node + * upwards. + */ + p->layer++; continue; - if (!(new = alloc_layer(idp))) { + } + if (!(new = get_from_free_list(idp))) { /* * The allocation failed. If we built part of * the structure tear it down. @@ -212,29 +238,50 @@ build_up: p = p->ary[0]; new->ary[0] = NULL; new->bitmap = new->count = 0; - __free_layer(idp, new); + __move_to_free_list(idp, new); } spin_unlock_irqrestore(&idp->lock, flags); return -1; } new->ary[0] = p; new->count = 1; + new->layer = layers-1; if (p->bitmap == IDR_FULL) __set_bit(0, &new->bitmap); p = new; } - idp->top = p; + rcu_assign_pointer(idp->top, p); idp->layers = layers; - v = sub_alloc(idp, ptr, &id); - if (v == -2) + v = sub_alloc(idp, &id, pa); + if (v == IDR_NEED_TO_GROW) goto build_up; return(v); } +static int idr_get_new_above_int(struct idr *idp, void *ptr, int starting_id) +{ + struct idr_layer *pa[MAX_LEVEL]; + int id; + + id = idr_get_empty_slot(idp, starting_id, pa); + if (id >= 0) { + /* + * Successfully found an empty slot. Install the user + * pointer and mark the slot full. + */ + rcu_assign_pointer(pa[0]->ary[id & IDR_MASK], + (struct idr_layer *)ptr); + pa[0]->count++; + idr_mark_full(pa, id); + } + + return id; +} + /** * idr_get_new_above - allocate new idr entry above or equal to a start id * @idp: idr handle - * @ptr: pointer you want associated with the ide + * @ptr: pointer you want associated with the id * @start_id: id to start search at * @id: pointer to the allocated handle * @@ -245,7 +292,7 @@ build_up: * and go back to the idr_pre_get() call. If the idr is full, it will * return -ENOSPC. * - * @id returns a value in the range 0 ... 0x7fffffff + * @id returns a value in the range @starting_id ... 0x7fffffff */ int idr_get_new_above(struct idr *idp, void *ptr, int starting_id, int *id) { @@ -256,12 +303,8 @@ int idr_get_new_above(struct idr *idp, void *ptr, int starting_id, int *id) * This is a cheap hack until the IDR code can be fixed to * return proper error values. */ - if (rv < 0) { - if (rv == -1) - return -EAGAIN; - else /* Will be -3 */ - return -ENOSPC; - } + if (rv < 0) + return _idr_rc_to_errno(rv); *id = rv; return 0; } @@ -270,7 +313,7 @@ EXPORT_SYMBOL(idr_get_new_above); /** * idr_get_new - allocate new idr entry * @idp: idr handle - * @ptr: pointer you want associated with the ide + * @ptr: pointer you want associated with the id * @id: pointer to the allocated handle * * This is the allocate id function. It should be called with any @@ -291,12 +334,8 @@ int idr_get_new(struct idr *idp, void *ptr, int *id) * This is a cheap hack until the IDR code can be fixed to * return proper error values. */ - if (rv < 0) { - if (rv == -1) - return -EAGAIN; - else /* Will be -3 */ - return -ENOSPC; - } + if (rv < 0) + return _idr_rc_to_errno(rv); *id = rv; return 0; } @@ -304,7 +343,8 @@ EXPORT_SYMBOL(idr_get_new); static void idr_remove_warning(int id) { - printk("idr_remove called for id=%d which is not allocated.\n", id); + printk(KERN_WARNING + "idr_remove called for id=%d which is not allocated.\n", id); dump_stack(); } @@ -313,6 +353,7 @@ static void sub_remove(struct idr *idp, int shift, int id) struct idr_layer *p = idp->top; struct idr_layer **pa[MAX_LEVEL]; struct idr_layer ***paa = &pa[0]; + struct idr_layer *to_free; int n; *paa = NULL; @@ -328,13 +369,18 @@ static void sub_remove(struct idr *idp, int shift, int id) n = id & IDR_MASK; if (likely(p != NULL && test_bit(n, &p->bitmap))){ __clear_bit(n, &p->bitmap); - p->ary[n] = NULL; + rcu_assign_pointer(p->ary[n], NULL); + to_free = NULL; while(*paa && ! --((**paa)->count)){ - free_layer(idp, **paa); + if (to_free) + free_layer(to_free); + to_free = **paa; **paa-- = NULL; } if (!*paa) idp->layers = 0; + if (to_free) + free_layer(to_free); } else idr_remove_warning(id); } @@ -347,36 +393,93 @@ static void sub_remove(struct idr *idp, int shift, int id) void idr_remove(struct idr *idp, int id) { struct idr_layer *p; + struct idr_layer *to_free; /* Mask off upper bits we don't use for the search. */ id &= MAX_ID_MASK; sub_remove(idp, (idp->layers - 1) * IDR_BITS, id); if (idp->top && idp->top->count == 1 && (idp->layers > 1) && - idp->top->ary[0]) { // We can drop a layer - + idp->top->ary[0]) { + /* + * Single child at leftmost slot: we can shrink the tree. + * This level is not needed anymore since when layers are + * inserted, they are inserted at the top of the existing + * tree. + */ + to_free = idp->top; p = idp->top->ary[0]; - idp->top->bitmap = idp->top->count = 0; - free_layer(idp, idp->top); - idp->top = p; + rcu_assign_pointer(idp->top, p); --idp->layers; + to_free->bitmap = to_free->count = 0; + free_layer(to_free); } while (idp->id_free_cnt >= IDR_FREE_MAX) { - p = alloc_layer(idp); + p = get_from_free_list(idp); + /* + * Note: we don't call the rcu callback here, since the only + * layers that fall into the freelist are those that have been + * preallocated. + */ kmem_cache_free(idr_layer_cache, p); - return; } + return; } EXPORT_SYMBOL(idr_remove); /** + * idr_remove_all - remove all ids from the given idr tree + * @idp: idr handle + * + * idr_destroy() only frees up unused, cached idp_layers, but this + * function will remove all id mappings and leave all idp_layers + * unused. + * + * A typical clean-up sequence for objects stored in an idr tree, will + * use idr_for_each() to free all objects, if necessay, then + * idr_remove_all() to remove all ids, and idr_destroy() to free + * up the cached idr_layers. + */ +void idr_remove_all(struct idr *idp) +{ + int n, id, max; + struct idr_layer *p; + struct idr_layer *pa[MAX_LEVEL]; + struct idr_layer **paa = &pa[0]; + + n = idp->layers * IDR_BITS; + p = idp->top; + rcu_assign_pointer(idp->top, NULL); + max = 1 << n; + + id = 0; + while (id < max) { + while (n > IDR_BITS && p) { + n -= IDR_BITS; + *paa++ = p; + p = p->ary[(id >> n) & IDR_MASK]; + } + + id += 1 << n; + while (n < fls(id)) { + if (p) + free_layer(p); + n += IDR_BITS; + p = *--paa; + } + } + idp->layers = 0; +} +EXPORT_SYMBOL(idr_remove_all); + +/** * idr_destroy - release all cached layers within an idr tree * idp: idr handle */ void idr_destroy(struct idr *idp) { while (idp->id_free_cnt) { - struct idr_layer *p = alloc_layer(idp); + struct idr_layer *p = get_from_free_list(idp); kmem_cache_free(idr_layer_cache, p); } } @@ -391,31 +494,137 @@ EXPORT_SYMBOL(idr_destroy); * return indicates that @id is not valid or you passed %NULL in * idr_get_new(). * - * The caller must serialize idr_find() vs idr_get_new() and idr_remove(). + * This function can be called under rcu_read_lock(), given that the leaf + * pointers lifetimes are correctly managed. */ void *idr_find(struct idr *idp, int id) { int n; struct idr_layer *p; - n = idp->layers * IDR_BITS; - p = idp->top; + p = rcu_dereference(idp->top); + if (!p) + return NULL; + n = (p->layer+1) * IDR_BITS; /* Mask off upper bits we don't use for the search. */ id &= MAX_ID_MASK; if (id >= (1 << n)) return NULL; + BUG_ON(n == 0); while (n > 0 && p) { n -= IDR_BITS; - p = p->ary[(id >> n) & IDR_MASK]; + BUG_ON(n != p->layer*IDR_BITS); + p = rcu_dereference(p->ary[(id >> n) & IDR_MASK]); } return((void *)p); } EXPORT_SYMBOL(idr_find); /** + * idr_for_each - iterate through all stored pointers + * @idp: idr handle + * @fn: function to be called for each pointer + * @data: data passed back to callback function + * + * Iterate over the pointers registered with the given idr. The + * callback function will be called for each pointer currently + * registered, passing the id, the pointer and the data pointer passed + * to this function. It is not safe to modify the idr tree while in + * the callback, so functions such as idr_get_new and idr_remove are + * not allowed. + * + * We check the return of @fn each time. If it returns anything other + * than 0, we break out and return that value. + * + * The caller must serialize idr_for_each() vs idr_get_new() and idr_remove(). + */ +int idr_for_each(struct idr *idp, + int (*fn)(int id, void *p, void *data), void *data) +{ + int n, id, max, error = 0; + struct idr_layer *p; + struct idr_layer *pa[MAX_LEVEL]; + struct idr_layer **paa = &pa[0]; + + n = idp->layers * IDR_BITS; + p = rcu_dereference(idp->top); + max = 1 << n; + + id = 0; + while (id < max) { + while (n > 0 && p) { + n -= IDR_BITS; + *paa++ = p; + p = rcu_dereference(p->ary[(id >> n) & IDR_MASK]); + } + + if (p) { + error = fn(id, (void *)p, data); + if (error) + break; + } + + id += 1 << n; + while (n < fls(id)) { + n += IDR_BITS; + p = *--paa; + } + } + + return error; +} +EXPORT_SYMBOL(idr_for_each); + +/** + * idr_get_next - lookup next object of id to given id. + * @idp: idr handle + * @id: pointer to lookup key + * + * Returns pointer to registered object with id, which is next number to + * given id. + */ + +void *idr_get_next(struct idr *idp, int *nextidp) +{ + struct idr_layer *p, *pa[MAX_LEVEL]; + struct idr_layer **paa = &pa[0]; + int id = *nextidp; + int n, max; + + /* find first ent */ + n = idp->layers * IDR_BITS; + max = 1 << n; + p = rcu_dereference(idp->top); + if (!p) + return NULL; + + while (id < max) { + while (n > 0 && p) { + n -= IDR_BITS; + *paa++ = p; + p = rcu_dereference(p->ary[(id >> n) & IDR_MASK]); + } + + if (p) { + *nextidp = id; + return p; + } + + id += 1 << n; + while (n < fls(id)) { + n += IDR_BITS; + p = *--paa; + } + } + return NULL; +} + + + +/** * idr_replace - replace pointer for given id * @idp: idr handle * @ptr: pointer you want associated with the id @@ -425,15 +634,18 @@ EXPORT_SYMBOL(idr_find); * A -ENOENT return indicates that @id was not found. * A -EINVAL return indicates that @id was not within valid constraints. * - * The caller must serialize vs idr_find(), idr_get_new(), and idr_remove(). + * The caller must serialize with writers. */ void *idr_replace(struct idr *idp, void *ptr, int id) { int n; struct idr_layer *p, *old_p; - n = idp->layers * IDR_BITS; p = idp->top; + if (!p) + return ERR_PTR(-EINVAL); + + n = (p->layer+1) * IDR_BITS; id &= MAX_ID_MASK; @@ -451,24 +663,16 @@ void *idr_replace(struct idr *idp, void *ptr, int id) return ERR_PTR(-ENOENT); old_p = p->ary[n]; - p->ary[n] = ptr; + rcu_assign_pointer(p->ary[n], ptr); return old_p; } EXPORT_SYMBOL(idr_replace); -static void idr_cache_ctor(void * idr_layer, struct kmem_cache *idr_layer_cache, - unsigned long flags) -{ - memset(idr_layer, 0, sizeof(struct idr_layer)); -} - -static int init_id_cache(void) +void __init idr_init_cache(void) { - if (!idr_layer_cache) - idr_layer_cache = kmem_cache_create("idr_layer_cache", - sizeof(struct idr_layer), 0, 0, idr_cache_ctor, NULL); - return 0; + idr_layer_cache = kmem_cache_create("idr_layer_cache", + sizeof(struct idr_layer), 0, SLAB_PANIC, NULL); } /** @@ -480,8 +684,249 @@ static int init_id_cache(void) */ void idr_init(struct idr *idp) { - init_id_cache(); memset(idp, 0, sizeof(struct idr)); spin_lock_init(&idp->lock); } EXPORT_SYMBOL(idr_init); + + +/* + * IDA - IDR based ID allocator + * + * this is id allocator without id -> pointer translation. Memory + * usage is much lower than full blown idr because each id only + * occupies a bit. ida uses a custom leaf node which contains + * IDA_BITMAP_BITS slots. + * + * 2007-04-25 written by Tejun Heo + */ + +static void free_bitmap(struct ida *ida, struct ida_bitmap *bitmap) +{ + unsigned long flags; + + if (!ida->free_bitmap) { + spin_lock_irqsave(&ida->idr.lock, flags); + if (!ida->free_bitmap) { + ida->free_bitmap = bitmap; + bitmap = NULL; + } + spin_unlock_irqrestore(&ida->idr.lock, flags); + } + + kfree(bitmap); +} + +/** + * ida_pre_get - reserve resources for ida allocation + * @ida: ida handle + * @gfp_mask: memory allocation flag + * + * This function should be called prior to locking and calling the + * following function. It preallocates enough memory to satisfy the + * worst possible allocation. + * + * If the system is REALLY out of memory this function returns 0, + * otherwise 1. + */ +int ida_pre_get(struct ida *ida, gfp_t gfp_mask) +{ + /* allocate idr_layers */ + if (!idr_pre_get(&ida->idr, gfp_mask)) + return 0; + + /* allocate free_bitmap */ + if (!ida->free_bitmap) { + struct ida_bitmap *bitmap; + + bitmap = kmalloc(sizeof(struct ida_bitmap), gfp_mask); + if (!bitmap) + return 0; + + free_bitmap(ida, bitmap); + } + + return 1; +} +EXPORT_SYMBOL(ida_pre_get); + +/** + * ida_get_new_above - allocate new ID above or equal to a start id + * @ida: ida handle + * @staring_id: id to start search at + * @p_id: pointer to the allocated handle + * + * Allocate new ID above or equal to @ida. It should be called with + * any required locks. + * + * If memory is required, it will return -EAGAIN, you should unlock + * and go back to the ida_pre_get() call. If the ida is full, it will + * return -ENOSPC. + * + * @p_id returns a value in the range @starting_id ... 0x7fffffff. + */ +int ida_get_new_above(struct ida *ida, int starting_id, int *p_id) +{ + struct idr_layer *pa[MAX_LEVEL]; + struct ida_bitmap *bitmap; + unsigned long flags; + int idr_id = starting_id / IDA_BITMAP_BITS; + int offset = starting_id % IDA_BITMAP_BITS; + int t, id; + + restart: + /* get vacant slot */ + t = idr_get_empty_slot(&ida->idr, idr_id, pa); + if (t < 0) + return _idr_rc_to_errno(t); + + if (t * IDA_BITMAP_BITS >= MAX_ID_BIT) + return -ENOSPC; + + if (t != idr_id) + offset = 0; + idr_id = t; + + /* if bitmap isn't there, create a new one */ + bitmap = (void *)pa[0]->ary[idr_id & IDR_MASK]; + if (!bitmap) { + spin_lock_irqsave(&ida->idr.lock, flags); + bitmap = ida->free_bitmap; + ida->free_bitmap = NULL; + spin_unlock_irqrestore(&ida->idr.lock, flags); + + if (!bitmap) + return -EAGAIN; + + memset(bitmap, 0, sizeof(struct ida_bitmap)); + rcu_assign_pointer(pa[0]->ary[idr_id & IDR_MASK], + (void *)bitmap); + pa[0]->count++; + } + + /* lookup for empty slot */ + t = find_next_zero_bit(bitmap->bitmap, IDA_BITMAP_BITS, offset); + if (t == IDA_BITMAP_BITS) { + /* no empty slot after offset, continue to the next chunk */ + idr_id++; + offset = 0; + goto restart; + } + + id = idr_id * IDA_BITMAP_BITS + t; + if (id >= MAX_ID_BIT) + return -ENOSPC; + + __set_bit(t, bitmap->bitmap); + if (++bitmap->nr_busy == IDA_BITMAP_BITS) + idr_mark_full(pa, idr_id); + + *p_id = id; + + /* Each leaf node can handle nearly a thousand slots and the + * whole idea of ida is to have small memory foot print. + * Throw away extra resources one by one after each successful + * allocation. + */ + if (ida->idr.id_free_cnt || ida->free_bitmap) { + struct idr_layer *p = get_from_free_list(&ida->idr); + if (p) + kmem_cache_free(idr_layer_cache, p); + } + + return 0; +} +EXPORT_SYMBOL(ida_get_new_above); + +/** + * ida_get_new - allocate new ID + * @ida: idr handle + * @p_id: pointer to the allocated handle + * + * Allocate new ID. It should be called with any required locks. + * + * If memory is required, it will return -EAGAIN, you should unlock + * and go back to the idr_pre_get() call. If the idr is full, it will + * return -ENOSPC. + * + * @id returns a value in the range 0 ... 0x7fffffff. + */ +int ida_get_new(struct ida *ida, int *p_id) +{ + return ida_get_new_above(ida, 0, p_id); +} +EXPORT_SYMBOL(ida_get_new); + +/** + * ida_remove - remove the given ID + * @ida: ida handle + * @id: ID to free + */ +void ida_remove(struct ida *ida, int id) +{ + struct idr_layer *p = ida->idr.top; + int shift = (ida->idr.layers - 1) * IDR_BITS; + int idr_id = id / IDA_BITMAP_BITS; + int offset = id % IDA_BITMAP_BITS; + int n; + struct ida_bitmap *bitmap; + + /* clear full bits while looking up the leaf idr_layer */ + while ((shift > 0) && p) { + n = (idr_id >> shift) & IDR_MASK; + __clear_bit(n, &p->bitmap); + p = p->ary[n]; + shift -= IDR_BITS; + } + + if (p == NULL) + goto err; + + n = idr_id & IDR_MASK; + __clear_bit(n, &p->bitmap); + + bitmap = (void *)p->ary[n]; + if (!test_bit(offset, bitmap->bitmap)) + goto err; + + /* update bitmap and remove it if empty */ + __clear_bit(offset, bitmap->bitmap); + if (--bitmap->nr_busy == 0) { + __set_bit(n, &p->bitmap); /* to please idr_remove() */ + idr_remove(&ida->idr, idr_id); + free_bitmap(ida, bitmap); + } + + return; + + err: + printk(KERN_WARNING + "ida_remove called for id=%d which is not allocated.\n", id); +} +EXPORT_SYMBOL(ida_remove); + +/** + * ida_destroy - release all cached layers within an ida tree + * ida: ida handle + */ +void ida_destroy(struct ida *ida) +{ + idr_destroy(&ida->idr); + kfree(ida->free_bitmap); +} +EXPORT_SYMBOL(ida_destroy); + +/** + * ida_init - initialize ida handle + * @ida: ida handle + * + * This function is use to set up the handle (@ida) that you will pass + * to the rest of the functions. + */ +void ida_init(struct ida *ida) +{ + memset(ida, 0, sizeof(struct ida)); + idr_init(&ida->idr); + +} +EXPORT_SYMBOL(ida_init);