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lib/idr.c
21.9 KB
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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. * |
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* Modified by Nadia Derbey to make it RCU safe. * |
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* Small id to pointer translation service. |
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* |
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* It uses a radix tree like structure as a sparse array indexed |
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* by the id to obtain the pointer. The bitmap makes allocating |
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* a new id quick. |
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* * 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. |
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* You can release ids at any time. When all ids are released, most of |
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* the memory is returned (we keep IDR_FREE_MAX) in a local pool so we |
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* don't need to go to the memory "store" during an id allocate, just |
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* 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/module.h> #endif |
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#include <linux/err.h> |
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#include <linux/string.h> #include <linux/idr.h> |
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static struct kmem_cache *idr_layer_cache; |
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|
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static struct idr_layer *get_from_free_list(struct idr *idp) |
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{ struct idr_layer *p; |
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unsigned long flags; |
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|
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spin_lock_irqsave(&idp->lock, flags); |
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if ((p = idp->id_free)) { idp->id_free = p->ary[0]; idp->id_free_cnt--; p->ary[0] = NULL; } |
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spin_unlock_irqrestore(&idp->lock, flags); |
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return(p); } |
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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); } |
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/* only called when idp->lock is held */ |
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static void __move_to_free_list(struct idr *idp, struct idr_layer *p) |
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{ p->ary[0] = idp->id_free; idp->id_free = p; idp->id_free_cnt++; } |
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static void move_to_free_list(struct idr *idp, struct idr_layer *p) |
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{ |
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unsigned long flags; |
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/* * Depends on the return element being zeroed. */ |
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spin_lock_irqsave(&idp->lock, flags); |
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__move_to_free_list(idp, p); |
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spin_unlock_irqrestore(&idp->lock, flags); |
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} |
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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); } } |
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/** |
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* idr_pre_get - reserve resources for idr allocation |
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* @idp: idr handle * @gfp_mask: memory allocation flags * |
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* 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. |
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* |
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* If the system is REALLY out of memory this function returns %0, * otherwise %1. |
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*/ |
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int idr_pre_get(struct idr *idp, gfp_t gfp_mask) |
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{ while (idp->id_free_cnt < IDR_FREE_MAX) { struct idr_layer *new; |
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new = kmem_cache_zalloc(idr_layer_cache, gfp_mask); |
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if (new == NULL) |
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return (0); |
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move_to_free_list(idp, new); |
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} return 1; } EXPORT_SYMBOL(idr_pre_get); |
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static int sub_alloc(struct idr *idp, int *starting_id, struct idr_layer **pa) |
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{ int n, m, sh; struct idr_layer *p, *new; |
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int l, id, oid; |
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unsigned long bm; |
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id = *starting_id; |
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restart: |
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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++; |
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oid = id; |
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id = (id | ((1 << (IDR_BITS * l)) - 1)) + 1; |
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/* if already at the top layer, we need to grow */ |
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if (id >= 1 << (idp->layers * IDR_BITS)) { |
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*starting_id = id; |
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return IDR_NEED_TO_GROW; |
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} |
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p = pa[l]; BUG_ON(!p); |
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/* 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; |
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} if (m != n) { sh = IDR_BITS*l; id = ((id >> sh) ^ n ^ m) << sh; } if ((id >= MAX_ID_BIT) || (id < 0)) |
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return IDR_NOMORE_SPACE; |
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if (l == 0) break; /* * Create the layer below if it is missing. */ if (!p->ary[m]) { |
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new = get_from_free_list(idp); if (!new) |
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return -1; |
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new->layer = l-1; |
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rcu_assign_pointer(p->ary[m], new); |
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p->count++; } pa[l--] = p; p = p->ary[m]; } |
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pa[l] = p; return id; |
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} |
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static int idr_get_empty_slot(struct idr *idp, int starting_id, struct idr_layer **pa) |
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{ struct idr_layer *p, *new; int layers, v, id; |
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unsigned long flags; |
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|
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id = starting_id; build_up: p = idp->top; layers = idp->layers; if (unlikely(!p)) { |
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if (!(p = get_from_free_list(idp))) |
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return -1; |
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p->layer = 0; |
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layers = 1; } /* * Add a new layer to the top of the tree if the requested * id is larger than the currently allocated space. */ |
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while ((layers < (MAX_LEVEL - 1)) && (id >= (1 << (layers*IDR_BITS)))) { |
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layers++; |
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if (!p->count) { /* special case: if the tree is currently empty, * then we grow the tree by moving the top node * upwards. */ p->layer++; |
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continue; |
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} |
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if (!(new = get_from_free_list(idp))) { |
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/* * The allocation failed. If we built part of * the structure tear it down. */ |
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spin_lock_irqsave(&idp->lock, flags); |
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for (new = p; p && p != idp->top; new = p) { p = p->ary[0]; new->ary[0] = NULL; new->bitmap = new->count = 0; |
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__move_to_free_list(idp, new); |
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} |
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spin_unlock_irqrestore(&idp->lock, flags); |
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return -1; } new->ary[0] = p; new->count = 1; |
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new->layer = layers-1; |
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if (p->bitmap == IDR_FULL) __set_bit(0, &new->bitmap); p = new; } |
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rcu_assign_pointer(idp->top, p); |
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idp->layers = layers; |
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v = sub_alloc(idp, &id, pa); |
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if (v == IDR_NEED_TO_GROW) |
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goto build_up; return(v); } |
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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. */ |
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rcu_assign_pointer(pa[0]->ary[id & IDR_MASK], (struct idr_layer *)ptr); |
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pa[0]->count++; idr_mark_full(pa, id); } return id; } |
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/** |
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* idr_get_new_above - allocate new idr entry above or equal to a start id |
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* @idp: idr handle |
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* @ptr: pointer you want associated with the id |
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* @starting_id: id to start search at |
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* @id: pointer to the allocated handle * * This is the allocate id function. It should be called with any * required locks. * |
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* If allocation from IDR's private freelist fails, idr_get_new_above() will |
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* return %-EAGAIN. The caller should retry the idr_pre_get() call to refill |
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* IDR's preallocation and then retry the idr_get_new_above() call. * |
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* If the idr is full idr_get_new_above() will return %-ENOSPC. |
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* |
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* @id returns a value in the range @starting_id ... %0x7fffffff |
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*/ int idr_get_new_above(struct idr *idp, void *ptr, int starting_id, int *id) { int rv; |
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|
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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. */ |
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if (rv < 0) return _idr_rc_to_errno(rv); |
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*id = rv; return 0; } EXPORT_SYMBOL(idr_get_new_above); /** * idr_get_new - allocate new idr entry * @idp: idr handle |
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* @ptr: pointer you want associated with the id |
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* @id: pointer to the allocated handle * |
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* If allocation from IDR's private freelist fails, idr_get_new_above() will |
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* return %-EAGAIN. The caller should retry the idr_pre_get() call to refill |
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* IDR's preallocation and then retry the idr_get_new_above() call. |
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* |
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* If the idr is full idr_get_new_above() will return %-ENOSPC. |
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* |
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* @id returns a value in the range %0 ... %0x7fffffff |
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*/ int idr_get_new(struct idr *idp, void *ptr, int *id) { int rv; |
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|
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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. */ |
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if (rv < 0) return _idr_rc_to_errno(rv); |
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*id = rv; return 0; } EXPORT_SYMBOL(idr_get_new); static void idr_remove_warning(int id) { |
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printk(KERN_WARNING "idr_remove called for id=%d which is not allocated. ", id); |
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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]; |
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struct idr_layer *to_free; |
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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); |
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rcu_assign_pointer(p->ary[n], NULL); to_free = NULL; |
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while(*paa && ! --((**paa)->count)){ |
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if (to_free) free_layer(to_free); to_free = **paa; |
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**paa-- = NULL; } |
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if (!*paa) |
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idp->layers = 0; |
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if (to_free) free_layer(to_free); |
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} else |
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idr_remove_warning(id); |
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} /** |
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* idr_remove - remove the given id and free its slot |
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* @idp: idr handle * @id: unique key |
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*/ void idr_remove(struct idr *idp, int id) { struct idr_layer *p; |
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struct idr_layer *to_free; |
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/* Mask off upper bits we don't use for the search. */ id &= MAX_ID_MASK; sub_remove(idp, (idp->layers - 1) * IDR_BITS, id); |
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if (idp->top && idp->top->count == 1 && (idp->layers > 1) && |
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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; |
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p = idp->top->ary[0]; |
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rcu_assign_pointer(idp->top, p); |
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--idp->layers; |
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to_free->bitmap = to_free->count = 0; free_layer(to_free); |
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} while (idp->id_free_cnt >= IDR_FREE_MAX) { |
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p = get_from_free_list(idp); |
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/* * Note: we don't call the rcu callback here, since the only * layers that fall into the freelist are those that have been * preallocated. */ |
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kmem_cache_free(idr_layer_cache, p); |
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} |
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return; |
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} EXPORT_SYMBOL(idr_remove); /** |
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* 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. * |
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* A typical clean-up sequence for objects stored in an idr tree will |
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* 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) { |
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int n, id, max; |
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439 |
int bt_mask; |
23936cc0b lib: add idr_remo... |
440 441 442 443 444 445 |
struct idr_layer *p; struct idr_layer *pa[MAX_LEVEL]; struct idr_layer **paa = &pa[0]; n = idp->layers * IDR_BITS; p = idp->top; |
1b23336ad idr: make idr_rem... |
446 |
rcu_assign_pointer(idp->top, NULL); |
23936cc0b lib: add idr_remo... |
447 448 449 |
max = 1 << n; id = 0; |
6ace06dc6 idr_remove_all: k... |
450 |
while (id < max) { |
23936cc0b lib: add idr_remo... |
451 452 453 454 455 |
while (n > IDR_BITS && p) { n -= IDR_BITS; *paa++ = p; p = p->ary[(id >> n) & IDR_MASK]; } |
2dcb22b34 idr: fix backtrac... |
456 |
bt_mask = id; |
23936cc0b lib: add idr_remo... |
457 |
id += 1 << n; |
2dcb22b34 idr: fix backtrac... |
458 459 |
/* Get the highest bit that the above add changed from 0->1. */ while (n < fls(id ^ bt_mask)) { |
cf481c20c idr: make idr_rem... |
460 461 |
if (p) free_layer(p); |
23936cc0b lib: add idr_remo... |
462 463 464 465 |
n += IDR_BITS; p = *--paa; } } |
23936cc0b lib: add idr_remo... |
466 467 468 469 470 |
idp->layers = 0; } EXPORT_SYMBOL(idr_remove_all); /** |
8d3b35914 [PATCH] inotify/i... |
471 |
* idr_destroy - release all cached layers within an idr tree |
ea24ea850 idr: fix kernel-d... |
472 |
* @idp: idr handle |
8d3b35914 [PATCH] inotify/i... |
473 474 475 476 |
*/ void idr_destroy(struct idr *idp) { while (idp->id_free_cnt) { |
4ae537892 idr: rename some ... |
477 |
struct idr_layer *p = get_from_free_list(idp); |
8d3b35914 [PATCH] inotify/i... |
478 479 480 481 482 483 |
kmem_cache_free(idr_layer_cache, p); } } EXPORT_SYMBOL(idr_destroy); /** |
1da177e4c Linux-2.6.12-rc2 |
484 485 486 487 488 489 490 491 |
* idr_find - return pointer for given id * @idp: idr handle * @id: lookup key * * Return the pointer given the id it has been registered with. A %NULL * return indicates that @id is not valid or you passed %NULL in * idr_get_new(). * |
f9c46d6ea idr: make idr_fin... |
492 493 |
* This function can be called under rcu_read_lock(), given that the leaf * pointers lifetimes are correctly managed. |
1da177e4c Linux-2.6.12-rc2 |
494 495 496 497 498 |
*/ void *idr_find(struct idr *idp, int id) { int n; struct idr_layer *p; |
96be753af idr: Apply lockde... |
499 |
p = rcu_dereference_raw(idp->top); |
6ff2d39b9 lib/idr.c: fix rc... |
500 501 502 |
if (!p) return NULL; n = (p->layer+1) * IDR_BITS; |
1da177e4c Linux-2.6.12-rc2 |
503 504 505 506 507 508 |
/* Mask off upper bits we don't use for the search. */ id &= MAX_ID_MASK; if (id >= (1 << n)) return NULL; |
6ff2d39b9 lib/idr.c: fix rc... |
509 |
BUG_ON(n == 0); |
1da177e4c Linux-2.6.12-rc2 |
510 511 512 |
while (n > 0 && p) { n -= IDR_BITS; |
6ff2d39b9 lib/idr.c: fix rc... |
513 |
BUG_ON(n != p->layer*IDR_BITS); |
96be753af idr: Apply lockde... |
514 |
p = rcu_dereference_raw(p->ary[(id >> n) & IDR_MASK]); |
1da177e4c Linux-2.6.12-rc2 |
515 516 517 518 |
} return((void *)p); } EXPORT_SYMBOL(idr_find); |
5806f07cd [PATCH] lib: add ... |
519 |
/** |
96d7fa421 lib: add idr_for_... |
520 521 522 523 524 525 526 527 528 529 530 531 532 |
* 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 |
56083ab17 docbook: add idr/... |
533 |
* than %0, we break out and return that value. |
96d7fa421 lib: add idr_for_... |
534 535 536 537 538 539 540 541 542 543 544 545 |
* * 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; |
96be753af idr: Apply lockde... |
546 |
p = rcu_dereference_raw(idp->top); |
96d7fa421 lib: add idr_for_... |
547 548 549 550 551 552 553 |
max = 1 << n; id = 0; while (id < max) { while (n > 0 && p) { n -= IDR_BITS; *paa++ = p; |
96be753af idr: Apply lockde... |
554 |
p = rcu_dereference_raw(p->ary[(id >> n) & IDR_MASK]); |
96d7fa421 lib: add idr_for_... |
555 556 557 558 559 560 561 562 563 564 565 566 567 568 569 570 571 572 573 574 |
} 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); /** |
38460b48d cgroup: CSS ID su... |
575 576 |
* idr_get_next - lookup next object of id to given id. * @idp: idr handle |
ea24ea850 idr: fix kernel-d... |
577 |
* @nextidp: pointer to lookup key |
38460b48d cgroup: CSS ID su... |
578 579 |
* * Returns pointer to registered object with id, which is next number to |
1458ce166 idr: describe how... |
580 581 |
* given id. After being looked up, *@nextidp will be updated for the next * iteration. |
38460b48d cgroup: CSS ID su... |
582 583 584 585 586 587 588 589 590 591 592 593 |
*/ 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; |
94bfa3b66 idr: fix RCU lock... |
594 |
p = rcu_dereference_raw(idp->top); |
38460b48d cgroup: CSS ID su... |
595 596 597 598 599 600 601 |
if (!p) return NULL; while (id < max) { while (n > 0 && p) { n -= IDR_BITS; *paa++ = p; |
94bfa3b66 idr: fix RCU lock... |
602 |
p = rcu_dereference_raw(p->ary[(id >> n) & IDR_MASK]); |
38460b48d cgroup: CSS ID su... |
603 604 605 606 607 608 609 610 611 612 613 614 615 616 617 |
} if (p) { *nextidp = id; return p; } id += 1 << n; while (n < fls(id)) { n += IDR_BITS; p = *--paa; } } return NULL; } |
4d1ee80f3 idr: export idr_g... |
618 |
EXPORT_SYMBOL(idr_get_next); |
38460b48d cgroup: CSS ID su... |
619 620 621 |
/** |
5806f07cd [PATCH] lib: add ... |
622 623 624 625 626 627 |
* idr_replace - replace pointer for given id * @idp: idr handle * @ptr: pointer you want associated with the id * @id: lookup key * * Replace the pointer registered with an id and return the old value. |
56083ab17 docbook: add idr/... |
628 629 |
* A %-ENOENT return indicates that @id was not found. * A %-EINVAL return indicates that @id was not within valid constraints. |
5806f07cd [PATCH] lib: add ... |
630 |
* |
cf481c20c idr: make idr_rem... |
631 |
* The caller must serialize with writers. |
5806f07cd [PATCH] lib: add ... |
632 633 634 635 636 |
*/ void *idr_replace(struct idr *idp, void *ptr, int id) { int n; struct idr_layer *p, *old_p; |
5806f07cd [PATCH] lib: add ... |
637 |
p = idp->top; |
6ff2d39b9 lib/idr.c: fix rc... |
638 639 640 641 |
if (!p) return ERR_PTR(-EINVAL); n = (p->layer+1) * IDR_BITS; |
5806f07cd [PATCH] lib: add ... |
642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 |
id &= MAX_ID_MASK; if (id >= (1 << n)) return ERR_PTR(-EINVAL); n -= IDR_BITS; while ((n > 0) && p) { p = p->ary[(id >> n) & IDR_MASK]; n -= IDR_BITS; } n = id & IDR_MASK; if (unlikely(p == NULL || !test_bit(n, &p->bitmap))) return ERR_PTR(-ENOENT); old_p = p->ary[n]; |
cf481c20c idr: make idr_rem... |
659 |
rcu_assign_pointer(p->ary[n], ptr); |
5806f07cd [PATCH] lib: add ... |
660 661 662 663 |
return old_p; } EXPORT_SYMBOL(idr_replace); |
199f0ca51 idr: create idr_l... |
664 |
void __init idr_init_cache(void) |
1da177e4c Linux-2.6.12-rc2 |
665 |
{ |
199f0ca51 idr: create idr_l... |
666 |
idr_layer_cache = kmem_cache_create("idr_layer_cache", |
5b019e990 lib/idr.c: use km... |
667 |
sizeof(struct idr_layer), 0, SLAB_PANIC, NULL); |
1da177e4c Linux-2.6.12-rc2 |
668 669 670 671 672 673 674 675 676 677 678 |
} /** * idr_init - initialize idr handle * @idp: idr handle * * This function is use to set up the handle (@idp) that you will pass * to the rest of the functions. */ void idr_init(struct idr *idp) { |
1da177e4c Linux-2.6.12-rc2 |
679 680 681 682 |
memset(idp, 0, sizeof(struct idr)); spin_lock_init(&idp->lock); } EXPORT_SYMBOL(idr_init); |
72dba584b ida: implement id... |
683 |
|
56083ab17 docbook: add idr/... |
684 685 |
/** * DOC: IDA description |
72dba584b ida: implement id... |
686 687 |
* IDA - IDR based ID allocator * |
56083ab17 docbook: add idr/... |
688 |
* This is id allocator without id -> pointer translation. Memory |
72dba584b ida: implement id... |
689 690 691 692 693 694 695 696 697 698 699 700 701 702 703 704 705 706 707 708 709 710 711 712 713 714 715 716 717 718 719 720 |
* 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 <htejun@gmail.com> */ 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. * |
56083ab17 docbook: add idr/... |
721 722 |
* If the system is REALLY out of memory this function returns %0, * otherwise %1. |
72dba584b ida: implement id... |
723 724 725 726 727 728 729 730 731 732 733 734 735 736 737 738 739 740 741 742 743 744 745 746 747 |
*/ 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 |
ea24ea850 idr: fix kernel-d... |
748 |
* @starting_id: id to start search at |
72dba584b ida: implement id... |
749 750 751 752 753 |
* @p_id: pointer to the allocated handle * * Allocate new ID above or equal to @ida. It should be called with * any required locks. * |
56083ab17 docbook: add idr/... |
754 |
* If memory is required, it will return %-EAGAIN, you should unlock |
72dba584b ida: implement id... |
755 |
* and go back to the ida_pre_get() call. If the ida is full, it will |
56083ab17 docbook: add idr/... |
756 |
* return %-ENOSPC. |
72dba584b ida: implement id... |
757 |
* |
56083ab17 docbook: add idr/... |
758 |
* @p_id returns a value in the range @starting_id ... %0x7fffffff. |
72dba584b ida: implement id... |
759 760 761 762 763 764 765 766 767 768 769 770 771 |
*/ 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); |
944ca05c7 idr: error checki... |
772 773 |
if (t < 0) return _idr_rc_to_errno(t); |
72dba584b ida: implement id... |
774 775 776 777 778 779 780 781 782 783 784 785 786 787 788 789 790 791 792 793 |
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)); |
3219b3b74 idr: make idr_get... |
794 795 |
rcu_assign_pointer(pa[0]->ary[idr_id & IDR_MASK], (void *)bitmap); |
72dba584b ida: implement id... |
796 797 798 799 800 801 802 803 804 805 806 807 808 809 810 811 812 813 814 815 816 817 818 819 820 821 822 823 |
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) { |
4ae537892 idr: rename some ... |
824 |
struct idr_layer *p = get_from_free_list(&ida->idr); |
72dba584b ida: implement id... |
825 826 827 828 829 830 831 832 833 834 835 836 837 838 839 |
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. * |
56083ab17 docbook: add idr/... |
840 |
* If memory is required, it will return %-EAGAIN, you should unlock |
72dba584b ida: implement id... |
841 |
* and go back to the idr_pre_get() call. If the idr is full, it will |
56083ab17 docbook: add idr/... |
842 |
* return %-ENOSPC. |
72dba584b ida: implement id... |
843 |
* |
56083ab17 docbook: add idr/... |
844 |
* @id returns a value in the range %0 ... %0x7fffffff. |
72dba584b ida: implement id... |
845 846 847 848 849 850 851 852 853 854 855 856 857 858 859 860 861 862 863 864 865 866 867 868 869 870 871 872 873 874 875 876 877 878 879 880 881 882 883 884 885 886 887 888 889 890 891 892 893 894 895 896 897 898 899 900 901 902 |
*/ 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. ", id); } EXPORT_SYMBOL(ida_remove); /** * ida_destroy - release all cached layers within an ida tree |
ea24ea850 idr: fix kernel-d... |
903 |
* @ida: ida handle |
72dba584b ida: implement id... |
904 905 906 907 908 909 910 911 912 913 914 915 916 917 918 919 920 921 922 923 924 925 |
*/ 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); |