/* * 2002-10-18 written by Jim Houston jim.houston@ccur.com * Copyright (C) 2002 by Concurrent Computer Corporation * Distributed under the GNU GPL license version 2. * * 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 * by the id to obtain the pointer. The bitmap makes allocating * a new id quick. * * You call it to allocate an id (an int) an associate with that id a * pointer or what ever, we treat it as a (void *). You can pass this * id to a user for him to pass back at a later time. You then pass * that id to this code and it returns your pointer. * You can release ids at any time. When all ids are released, most of * the memory is returned (we keep IDR_FREE_MAX) in a local pool so we * don't need to go to the memory "store" during an id allocate, just * so you don't need to be too concerned about locking and conflicts * with the slab allocator. */ #ifndef TEST // to test in user space...#include <linux/slab.h>#include <linux/init.h>#include <linux/export.h>#endif#include <linux/err.h>#include <linux/string.h>#include <linux/idr.h>#include <linux/spinlock.h> static struct kmem_cache *idr_layer_cache;static DEFINE_SPINLOCK(simple_ida_lock); static struct idr_layer *get_from_free_list(struct idr *idp){ struct idr_layer *p; unsigned long flags; spin_lock_irqsave(&idp->lock, flags); if ((p = idp->id_free)) { idp->id_free = p->ary[0]; idp->id_free_cnt--; p->ary[0] = NULL; } spin_unlock_irqrestore(&idp->lock, flags); 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 __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 move_to_free_list(struct idr *idp, struct idr_layer *p){ unsigned long flags; /* * Depends on the return element being zeroed. */ spin_lock_irqsave(&idp->lock, flags); __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 - reserve resources for idr allocation * @idp: idr handle * @gfp_mask: memory allocation flags * * This function should be called prior to calling the idr_get_new* functions. * It preallocates enough memory to satisfy the worst possible allocation. The * caller should pass in GFP_KERNEL if possible. This of course requires that * no spinning locks be held. * * If the system is REALLY out of memory this function returns %0, * otherwise %1. */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_zalloc(idr_layer_cache, gfp_mask); if (new == NULL) return (0); move_to_free_list(idp, new); } return 1;}EXPORT_SYMBOL(idr_pre_get); static int sub_alloc(struct idr *idp, int *starting_id, struct idr_layer **pa){ int n, m, sh; struct idr_layer *p, *new; int l, id, oid; unsigned long bm; id = *starting_id; restart: p = idp->top; l = idp->layers; pa[l--] = NULL; while (1) { /* * We run around this while until we reach the leaf node... */ n = (id >> (IDR_BITS*l)) & IDR_MASK; bm = ~p->bitmap; m = find_next_bit(&bm, IDR_SIZE, n); if (m == IDR_SIZE) { /* no space available go back to previous layer. */ l++; oid = id; id = (id | ((1 << (IDR_BITS * l)) - 1)) + 1; /* if already at the top layer, we need to grow */ if (id >= 1 << (idp->layers * IDR_BITS)) { *starting_id = id; return IDR_NEED_TO_GROW; } p = pa[l]; BUG_ON(!p); /* If we need to go up one layer, continue the * loop; otherwise, restart from the top. */ sh = IDR_BITS * (l + 1); if (oid >> sh == id >> sh) continue; else goto restart; } if (m != n) { sh = IDR_BITS*l; id = ((id >> sh) ^ n ^ m) << sh; } if ((id >= MAX_ID_BIT) || (id < 0)) return IDR_NOMORE_SPACE; if (l == 0) break; /* * Create the layer below if it is missing. */ if (!p->ary[m]) { new = get_from_free_list(idp); if (!new) return -1; new->layer = l-1; rcu_assign_pointer(p->ary[m], new); p->count++; } pa[l--] = p; p = p->ary[m]; } pa[l] = p; return 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; unsigned long flags; id = starting_id;build_up: p = idp->top; layers = idp->layers; if (unlikely(!p)) { if (!(p = get_from_free_list(idp))) return -1; p->layer = 0; layers = 1; } /* * Add a new layer to the top of the tree if the requested * id is larger than the currently allocated space. */ while ((layers < (MAX_LEVEL - 1)) && (id >= (1 << (layers*IDR_BITS)))) { layers++; 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 = get_from_free_list(idp))) { /* * The allocation failed. If we built part of * the structure tear it down. */ spin_lock_irqsave(&idp->lock, flags); for (new = p; p && p != idp->top; new = p) { p = p->ary[0]; new->ary[0] = NULL; new->bitmap = new->count = 0; __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; } rcu_assign_pointer(idp->top, p); idp->layers = layers; 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 id * @starting_id: id to start search at * @id: pointer to the allocated handle * * This is the allocate id function. It should be called with any * required locks. * * If allocation from IDR's private freelist fails, idr_get_new_above() will * return %-EAGAIN. The caller should retry the idr_pre_get() call to refill * IDR's preallocation and then retry the idr_get_new_above() call. * * If the idr is full idr_get_new_above() will return %-ENOSPC. * * @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){ int rv; rv = idr_get_new_above_int(idp, ptr, starting_id); /* * This is a cheap hack until the IDR code can be fixed to * return proper error values. */ if (rv < 0) return _idr_rc_to_errno(rv); *id = rv; return 0;}EXPORT_SYMBOL(idr_get_new_above); /** * idr_get_new - allocate new idr entry * @idp: idr handle * @ptr: pointer you want associated with the id * @id: pointer to the allocated handle * * If allocation from IDR's private freelist fails, idr_get_new_above() will * return %-EAGAIN. The caller should retry the idr_pre_get() call to refill * IDR's preallocation and then retry the idr_get_new_above() call. * * If the idr is full idr_get_new_above() will return %-ENOSPC. * * @id returns a value in the range %0 ... %0x7fffffff */int idr_get_new(struct idr *idp, void *ptr, int *id){ int rv; rv = idr_get_new_above_int(idp, ptr, 0); /* * This is a cheap hack until the IDR code can be fixed to * return proper error values. */ if (rv < 0) return _idr_rc_to_errno(rv); *id = rv; return 0;}EXPORT_SYMBOL(idr_get_new); static void idr_remove_warning(int id){ printk(KERN_WARNING "idr_remove called for id=%d which is not allocated.\n", id); dump_stack();} 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; *++paa = &idp->top; while ((shift > 0) && p) { n = (id >> shift) & IDR_MASK; __clear_bit(n, &p->bitmap); *++paa = &p->ary[n]; p = p->ary[n]; shift -= IDR_BITS; } n = id & IDR_MASK; if (likely(p != NULL && test_bit(n, &p->bitmap))){ __clear_bit(n, &p->bitmap); rcu_assign_pointer(p->ary[n], NULL); to_free = NULL; while(*paa && ! --((**paa)->count)){ 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);} /** * idr_remove - remove the given id and free its slot * @idp: idr handle * @id: unique key */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]) { /* * 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]; 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 = 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;}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; int bt_mask; 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]; } bt_mask = id; id += 1 << n; /* Get the highest bit that the above add changed from 0->1. */ while (n < fls(id ^ bt_mask)) { 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 = get_from_free_list(idp); kmem_cache_free(idr_layer_cache, p); }}EXPORT_SYMBOL(idr_destroy); /** * idr_find - return pointer for given id * @idp: idr handle * @id: lookup keyLines 1–500 of 1013. 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/* * 2002-10-18 written by Jim Houston jim.houston@ccur.com * Copyright (C) 2002 by Concurrent Computer Corporation * Distributed under the GNU GPL license version 2. * * 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 * by the id to obtain the pointer. The bitmap makes allocating * a new id quick. * * You call it to allocate an id (an int) an associate with that id a * pointer or what ever, we treat it as a (void *). You can pass this * id to a user for him to pass back at a later time. You then pass * that id to this code and it returns your pointer. * You can release ids at any time. When all ids are released, most of * the memory is returned (we keep IDR_FREE_MAX) in a local pool so we * don't need to go to the memory "store" during an id allocate, just * so you don't need to be too concerned about locking and conflicts * with the slab allocator. */ #ifndef TEST // to test in user space... #include <linux/slab.h> #include <linux/init.h> #include <linux/export.h> #endif #include <linux/err.h> #include <linux/string.h> #include <linux/idr.h> #include <linux/spinlock.h> static struct kmem_cache *idr_layer_cache; static DEFINE_SPINLOCK(simple_ida_lock); static struct idr_layer *get_from_free_list(struct idr *idp) { struct idr_layer *p; unsigned long flags; spin_lock_irqsave(&idp->lock, flags); if ((p = idp->id_free)) { idp->id_free = p->ary[0]; idp->id_free_cnt--; p->ary[0] = NULL; } spin_unlock_irqrestore(&idp->lock, flags); 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 __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 move_to_free_list(struct idr *idp, struct idr_layer *p) { unsigned long flags; /* * Depends on the return element being zeroed. */ spin_lock_irqsave(&idp->lock, flags); __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 - reserve resources for idr allocation * @idp: idr handle * @gfp_mask: memory allocation flags * * This function should be called prior to calling the idr_get_new* functions. * It preallocates enough memory to satisfy the worst possible allocation. The * caller should pass in GFP_KERNEL if possible. This of course requires that * no spinning locks be held. * * If the system is REALLY out of memory this function returns %0, * otherwise %1. */ 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_zalloc(idr_layer_cache, gfp_mask); if (new == NULL) return (0); move_to_free_list(idp, new); } return 1; } EXPORT_SYMBOL(idr_pre_get); static int sub_alloc(struct idr *idp, int *starting_id, struct idr_layer **pa) { int n, m, sh; struct idr_layer *p, *new; int l, id, oid; unsigned long bm; id = *starting_id; restart: p = idp->top; l = idp->layers; pa[l--] = NULL; while (1) { /* * We run around this while until we reach the leaf node... */ n = (id >> (IDR_BITS*l)) & IDR_MASK; bm = ~p->bitmap; m = find_next_bit(&bm, IDR_SIZE, n); if (m == IDR_SIZE) { /* no space available go back to previous layer. */ l++; oid = id; id = (id | ((1 << (IDR_BITS * l)) - 1)) + 1; /* if already at the top layer, we need to grow */ if (id >= 1 << (idp->layers * IDR_BITS)) { *starting_id = id; return IDR_NEED_TO_GROW; } p = pa[l]; BUG_ON(!p); /* If we need to go up one layer, continue the * loop; otherwise, restart from the top. */ sh = IDR_BITS * (l + 1); if (oid >> sh == id >> sh) continue; else goto restart; } if (m != n) { sh = IDR_BITS*l; id = ((id >> sh) ^ n ^ m) << sh; } if ((id >= MAX_ID_BIT) || (id < 0)) return IDR_NOMORE_SPACE; if (l == 0) break; /* * Create the layer below if it is missing. */ if (!p->ary[m]) { new = get_from_free_list(idp); if (!new) return -1; new->layer = l-1; rcu_assign_pointer(p->ary[m], new); p->count++; } pa[l--] = p; p = p->ary[m]; } pa[l] = p; return 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; unsigned long flags; id = starting_id; build_up: p = idp->top; layers = idp->layers; if (unlikely(!p)) { if (!(p = get_from_free_list(idp))) return -1; p->layer = 0; layers = 1; } /* * Add a new layer to the top of the tree if the requested * id is larger than the currently allocated space. */ while ((layers < (MAX_LEVEL - 1)) && (id >= (1 << (layers*IDR_BITS)))) { layers++; 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 = get_from_free_list(idp))) { /* * The allocation failed. If we built part of * the structure tear it down. */ spin_lock_irqsave(&idp->lock, flags); for (new = p; p && p != idp->top; new = p) { p = p->ary[0]; new->ary[0] = NULL; new->bitmap = new->count = 0; __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; } rcu_assign_pointer(idp->top, p); idp->layers = layers; 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 id * @starting_id: id to start search at * @id: pointer to the allocated handle * * This is the allocate id function. It should be called with any * required locks. * * If allocation from IDR's private freelist fails, idr_get_new_above() will * return %-EAGAIN. The caller should retry the idr_pre_get() call to refill * IDR's preallocation and then retry the idr_get_new_above() call. * * If the idr is full idr_get_new_above() will return %-ENOSPC. * * @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) { int rv; rv = idr_get_new_above_int(idp, ptr, starting_id); /* * This is a cheap hack until the IDR code can be fixed to * return proper error values. */ if (rv < 0) return _idr_rc_to_errno(rv); *id = rv; return 0; } EXPORT_SYMBOL(idr_get_new_above); /** * idr_get_new - allocate new idr entry * @idp: idr handle * @ptr: pointer you want associated with the id * @id: pointer to the allocated handle * * If allocation from IDR's private freelist fails, idr_get_new_above() will * return %-EAGAIN. The caller should retry the idr_pre_get() call to refill * IDR's preallocation and then retry the idr_get_new_above() call. * * If the idr is full idr_get_new_above() will return %-ENOSPC. * * @id returns a value in the range %0 ... %0x7fffffff */ int idr_get_new(struct idr *idp, void *ptr, int *id) { int rv; rv = idr_get_new_above_int(idp, ptr, 0); /* * This is a cheap hack until the IDR code can be fixed to * return proper error values. */ if (rv < 0) return _idr_rc_to_errno(rv); *id = rv; return 0; } EXPORT_SYMBOL(idr_get_new); static void idr_remove_warning(int id) { printk(KERN_WARNING "idr_remove called for id=%d which is not allocated.\n", id); dump_stack(); } 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; *++paa = &idp->top; while ((shift > 0) && p) { n = (id >> shift) & IDR_MASK; __clear_bit(n, &p->bitmap); *++paa = &p->ary[n]; p = p->ary[n]; shift -= IDR_BITS; } n = id & IDR_MASK; if (likely(p != NULL && test_bit(n, &p->bitmap))){ __clear_bit(n, &p->bitmap); rcu_assign_pointer(p->ary[n], NULL); to_free = NULL; while(*paa && ! --((**paa)->count)){ 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); } /** * idr_remove - remove the given id and free its slot * @idp: idr handle * @id: unique key */ 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]) { /* * 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]; 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 = 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; } 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; int bt_mask; 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]; } bt_mask = id; id += 1 << n; /* Get the highest bit that the above add changed from 0->1. */ while (n < fls(id ^ bt_mask)) { 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 = get_from_free_list(idp); kmem_cache_free(idr_layer_cache, p); } } EXPORT_SYMBOL(idr_destroy); /** * idr_find - return pointer for given id * @idp: idr handle * @id: lookup key