11da177e4SLinus Torvalds /* 21da177e4SLinus Torvalds * 2002-10-18 written by Jim Houston jim.houston@ccur.com 31da177e4SLinus Torvalds * Copyright (C) 2002 by Concurrent Computer Corporation 41da177e4SLinus Torvalds * Distributed under the GNU GPL license version 2. 51da177e4SLinus Torvalds * 61da177e4SLinus Torvalds * Modified by George Anzinger to reuse immediately and to use 71da177e4SLinus Torvalds * find bit instructions. Also removed _irq on spinlocks. 81da177e4SLinus Torvalds * 93219b3b7SNadia Derbey * Modified by Nadia Derbey to make it RCU safe. 103219b3b7SNadia Derbey * 111da177e4SLinus Torvalds * Small id to pointer translation service. 121da177e4SLinus Torvalds * 131da177e4SLinus Torvalds * It uses a radix tree like structure as a sparse array indexed 141da177e4SLinus Torvalds * by the id to obtain the pointer. The bitmap makes allocating 151da177e4SLinus Torvalds * a new id quick. 161da177e4SLinus Torvalds * 171da177e4SLinus Torvalds * You call it to allocate an id (an int) an associate with that id a 181da177e4SLinus Torvalds * pointer or what ever, we treat it as a (void *). You can pass this 191da177e4SLinus Torvalds * id to a user for him to pass back at a later time. You then pass 201da177e4SLinus Torvalds * that id to this code and it returns your pointer. 211da177e4SLinus Torvalds 221da177e4SLinus Torvalds * You can release ids at any time. When all ids are released, most of 231da177e4SLinus Torvalds * the memory is returned (we keep IDR_FREE_MAX) in a local pool so we 241da177e4SLinus Torvalds * don't need to go to the memory "store" during an id allocate, just 251da177e4SLinus Torvalds * so you don't need to be too concerned about locking and conflicts 261da177e4SLinus Torvalds * with the slab allocator. 271da177e4SLinus Torvalds */ 281da177e4SLinus Torvalds 291da177e4SLinus Torvalds #ifndef TEST // to test in user space... 301da177e4SLinus Torvalds #include <linux/slab.h> 311da177e4SLinus Torvalds #include <linux/init.h> 321da177e4SLinus Torvalds #include <linux/module.h> 331da177e4SLinus Torvalds #endif 345806f07cSJeff Mahoney #include <linux/err.h> 351da177e4SLinus Torvalds #include <linux/string.h> 361da177e4SLinus Torvalds #include <linux/idr.h> 371da177e4SLinus Torvalds 38e18b890bSChristoph Lameter static struct kmem_cache *idr_layer_cache; 391da177e4SLinus Torvalds 404ae53789SNadia Derbey static struct idr_layer *get_from_free_list(struct idr *idp) 411da177e4SLinus Torvalds { 421da177e4SLinus Torvalds struct idr_layer *p; 43c259cc28SRoland Dreier unsigned long flags; 441da177e4SLinus Torvalds 45c259cc28SRoland Dreier spin_lock_irqsave(&idp->lock, flags); 461da177e4SLinus Torvalds if ((p = idp->id_free)) { 471da177e4SLinus Torvalds idp->id_free = p->ary[0]; 481da177e4SLinus Torvalds idp->id_free_cnt--; 491da177e4SLinus Torvalds p->ary[0] = NULL; 501da177e4SLinus Torvalds } 51c259cc28SRoland Dreier spin_unlock_irqrestore(&idp->lock, flags); 521da177e4SLinus Torvalds return(p); 531da177e4SLinus Torvalds } 541da177e4SLinus Torvalds 55cf481c20SNadia Derbey static void idr_layer_rcu_free(struct rcu_head *head) 56cf481c20SNadia Derbey { 57cf481c20SNadia Derbey struct idr_layer *layer; 58cf481c20SNadia Derbey 59cf481c20SNadia Derbey layer = container_of(head, struct idr_layer, rcu_head); 60cf481c20SNadia Derbey kmem_cache_free(idr_layer_cache, layer); 61cf481c20SNadia Derbey } 62cf481c20SNadia Derbey 63cf481c20SNadia Derbey static inline void free_layer(struct idr_layer *p) 64cf481c20SNadia Derbey { 65cf481c20SNadia Derbey call_rcu(&p->rcu_head, idr_layer_rcu_free); 66cf481c20SNadia Derbey } 67cf481c20SNadia Derbey 681eec0056SSonny Rao /* only called when idp->lock is held */ 694ae53789SNadia Derbey static void __move_to_free_list(struct idr *idp, struct idr_layer *p) 701eec0056SSonny Rao { 711eec0056SSonny Rao p->ary[0] = idp->id_free; 721eec0056SSonny Rao idp->id_free = p; 731eec0056SSonny Rao idp->id_free_cnt++; 741eec0056SSonny Rao } 751eec0056SSonny Rao 764ae53789SNadia Derbey static void move_to_free_list(struct idr *idp, struct idr_layer *p) 771da177e4SLinus Torvalds { 78c259cc28SRoland Dreier unsigned long flags; 79c259cc28SRoland Dreier 801da177e4SLinus Torvalds /* 811da177e4SLinus Torvalds * Depends on the return element being zeroed. 821da177e4SLinus Torvalds */ 83c259cc28SRoland Dreier spin_lock_irqsave(&idp->lock, flags); 844ae53789SNadia Derbey __move_to_free_list(idp, p); 85c259cc28SRoland Dreier spin_unlock_irqrestore(&idp->lock, flags); 861da177e4SLinus Torvalds } 871da177e4SLinus Torvalds 88e33ac8bdSTejun Heo static void idr_mark_full(struct idr_layer **pa, int id) 89e33ac8bdSTejun Heo { 90e33ac8bdSTejun Heo struct idr_layer *p = pa[0]; 91e33ac8bdSTejun Heo int l = 0; 92e33ac8bdSTejun Heo 93e33ac8bdSTejun Heo __set_bit(id & IDR_MASK, &p->bitmap); 94e33ac8bdSTejun Heo /* 95e33ac8bdSTejun Heo * If this layer is full mark the bit in the layer above to 96e33ac8bdSTejun Heo * show that this part of the radix tree is full. This may 97e33ac8bdSTejun Heo * complete the layer above and require walking up the radix 98e33ac8bdSTejun Heo * tree. 99e33ac8bdSTejun Heo */ 100e33ac8bdSTejun Heo while (p->bitmap == IDR_FULL) { 101e33ac8bdSTejun Heo if (!(p = pa[++l])) 102e33ac8bdSTejun Heo break; 103e33ac8bdSTejun Heo id = id >> IDR_BITS; 104e33ac8bdSTejun Heo __set_bit((id & IDR_MASK), &p->bitmap); 105e33ac8bdSTejun Heo } 106e33ac8bdSTejun Heo } 107e33ac8bdSTejun Heo 1081da177e4SLinus Torvalds /** 1091da177e4SLinus Torvalds * idr_pre_get - reserver resources for idr allocation 1101da177e4SLinus Torvalds * @idp: idr handle 1111da177e4SLinus Torvalds * @gfp_mask: memory allocation flags 1121da177e4SLinus Torvalds * 1131da177e4SLinus Torvalds * This function should be called prior to locking and calling the 1143219b3b7SNadia Derbey * idr_get_new* functions. It preallocates enough memory to satisfy 1151da177e4SLinus Torvalds * the worst possible allocation. 1161da177e4SLinus Torvalds * 1171da177e4SLinus Torvalds * If the system is REALLY out of memory this function returns 0, 1181da177e4SLinus Torvalds * otherwise 1. 1191da177e4SLinus Torvalds */ 120fd4f2df2SAl Viro int idr_pre_get(struct idr *idp, gfp_t gfp_mask) 1211da177e4SLinus Torvalds { 1221da177e4SLinus Torvalds while (idp->id_free_cnt < IDR_FREE_MAX) { 1231da177e4SLinus Torvalds struct idr_layer *new; 1245b019e99SAndrew Morton new = kmem_cache_zalloc(idr_layer_cache, gfp_mask); 1251da177e4SLinus Torvalds if (new == NULL) 1261da177e4SLinus Torvalds return (0); 1274ae53789SNadia Derbey move_to_free_list(idp, new); 1281da177e4SLinus Torvalds } 1291da177e4SLinus Torvalds return 1; 1301da177e4SLinus Torvalds } 1311da177e4SLinus Torvalds EXPORT_SYMBOL(idr_pre_get); 1321da177e4SLinus Torvalds 133e33ac8bdSTejun Heo static int sub_alloc(struct idr *idp, int *starting_id, struct idr_layer **pa) 1341da177e4SLinus Torvalds { 1351da177e4SLinus Torvalds int n, m, sh; 1361da177e4SLinus Torvalds struct idr_layer *p, *new; 1377aae6dd8STejun Heo int l, id, oid; 1385ba25331SAl Viro unsigned long bm; 1391da177e4SLinus Torvalds 1401da177e4SLinus Torvalds id = *starting_id; 1417aae6dd8STejun Heo restart: 1421da177e4SLinus Torvalds p = idp->top; 1431da177e4SLinus Torvalds l = idp->layers; 1441da177e4SLinus Torvalds pa[l--] = NULL; 1451da177e4SLinus Torvalds while (1) { 1461da177e4SLinus Torvalds /* 1471da177e4SLinus Torvalds * We run around this while until we reach the leaf node... 1481da177e4SLinus Torvalds */ 1491da177e4SLinus Torvalds n = (id >> (IDR_BITS*l)) & IDR_MASK; 1501da177e4SLinus Torvalds bm = ~p->bitmap; 1511da177e4SLinus Torvalds m = find_next_bit(&bm, IDR_SIZE, n); 1521da177e4SLinus Torvalds if (m == IDR_SIZE) { 1531da177e4SLinus Torvalds /* no space available go back to previous layer. */ 1541da177e4SLinus Torvalds l++; 1557aae6dd8STejun Heo oid = id; 1561da177e4SLinus Torvalds id = (id | ((1 << (IDR_BITS * l)) - 1)) + 1; 1577aae6dd8STejun Heo 1587aae6dd8STejun Heo /* if already at the top layer, we need to grow */ 1591da177e4SLinus Torvalds if (!(p = pa[l])) { 1601da177e4SLinus Torvalds *starting_id = id; 161944ca05cSNadia Derbey return IDR_NEED_TO_GROW; 1621da177e4SLinus Torvalds } 1637aae6dd8STejun Heo 1647aae6dd8STejun Heo /* If we need to go up one layer, continue the 1657aae6dd8STejun Heo * loop; otherwise, restart from the top. 1667aae6dd8STejun Heo */ 1677aae6dd8STejun Heo sh = IDR_BITS * (l + 1); 1687aae6dd8STejun Heo if (oid >> sh == id >> sh) 1691da177e4SLinus Torvalds continue; 1707aae6dd8STejun Heo else 1717aae6dd8STejun Heo goto restart; 1721da177e4SLinus Torvalds } 1731da177e4SLinus Torvalds if (m != n) { 1741da177e4SLinus Torvalds sh = IDR_BITS*l; 1751da177e4SLinus Torvalds id = ((id >> sh) ^ n ^ m) << sh; 1761da177e4SLinus Torvalds } 1771da177e4SLinus Torvalds if ((id >= MAX_ID_BIT) || (id < 0)) 178944ca05cSNadia Derbey return IDR_NOMORE_SPACE; 1791da177e4SLinus Torvalds if (l == 0) 1801da177e4SLinus Torvalds break; 1811da177e4SLinus Torvalds /* 1821da177e4SLinus Torvalds * Create the layer below if it is missing. 1831da177e4SLinus Torvalds */ 1841da177e4SLinus Torvalds if (!p->ary[m]) { 1854ae53789SNadia Derbey new = get_from_free_list(idp); 1864ae53789SNadia Derbey if (!new) 1871da177e4SLinus Torvalds return -1; 1886ff2d39bSManfred Spraul new->layer = l-1; 1893219b3b7SNadia Derbey rcu_assign_pointer(p->ary[m], new); 1901da177e4SLinus Torvalds p->count++; 1911da177e4SLinus Torvalds } 1921da177e4SLinus Torvalds pa[l--] = p; 1931da177e4SLinus Torvalds p = p->ary[m]; 1941da177e4SLinus Torvalds } 195e33ac8bdSTejun Heo 196e33ac8bdSTejun Heo pa[l] = p; 197e33ac8bdSTejun Heo return id; 1981da177e4SLinus Torvalds } 1991da177e4SLinus Torvalds 200e33ac8bdSTejun Heo static int idr_get_empty_slot(struct idr *idp, int starting_id, 201e33ac8bdSTejun Heo struct idr_layer **pa) 2021da177e4SLinus Torvalds { 2031da177e4SLinus Torvalds struct idr_layer *p, *new; 2041da177e4SLinus Torvalds int layers, v, id; 205c259cc28SRoland Dreier unsigned long flags; 2061da177e4SLinus Torvalds 2071da177e4SLinus Torvalds id = starting_id; 2081da177e4SLinus Torvalds build_up: 2091da177e4SLinus Torvalds p = idp->top; 2101da177e4SLinus Torvalds layers = idp->layers; 2111da177e4SLinus Torvalds if (unlikely(!p)) { 2124ae53789SNadia Derbey if (!(p = get_from_free_list(idp))) 2131da177e4SLinus Torvalds return -1; 2146ff2d39bSManfred Spraul p->layer = 0; 2151da177e4SLinus Torvalds layers = 1; 2161da177e4SLinus Torvalds } 2171da177e4SLinus Torvalds /* 2181da177e4SLinus Torvalds * Add a new layer to the top of the tree if the requested 2191da177e4SLinus Torvalds * id is larger than the currently allocated space. 2201da177e4SLinus Torvalds */ 221589777eaSZaur Kambarov while ((layers < (MAX_LEVEL - 1)) && (id >= (1 << (layers*IDR_BITS)))) { 2221da177e4SLinus Torvalds layers++; 223711a49a0SManfred Spraul if (!p->count) { 224711a49a0SManfred Spraul /* special case: if the tree is currently empty, 225711a49a0SManfred Spraul * then we grow the tree by moving the top node 226711a49a0SManfred Spraul * upwards. 227711a49a0SManfred Spraul */ 228711a49a0SManfred Spraul p->layer++; 2291da177e4SLinus Torvalds continue; 230711a49a0SManfred Spraul } 2314ae53789SNadia Derbey if (!(new = get_from_free_list(idp))) { 2321da177e4SLinus Torvalds /* 2331da177e4SLinus Torvalds * The allocation failed. If we built part of 2341da177e4SLinus Torvalds * the structure tear it down. 2351da177e4SLinus Torvalds */ 236c259cc28SRoland Dreier spin_lock_irqsave(&idp->lock, flags); 2371da177e4SLinus Torvalds for (new = p; p && p != idp->top; new = p) { 2381da177e4SLinus Torvalds p = p->ary[0]; 2391da177e4SLinus Torvalds new->ary[0] = NULL; 2401da177e4SLinus Torvalds new->bitmap = new->count = 0; 2414ae53789SNadia Derbey __move_to_free_list(idp, new); 2421da177e4SLinus Torvalds } 243c259cc28SRoland Dreier spin_unlock_irqrestore(&idp->lock, flags); 2441da177e4SLinus Torvalds return -1; 2451da177e4SLinus Torvalds } 2461da177e4SLinus Torvalds new->ary[0] = p; 2471da177e4SLinus Torvalds new->count = 1; 2486ff2d39bSManfred Spraul new->layer = layers-1; 2491da177e4SLinus Torvalds if (p->bitmap == IDR_FULL) 2501da177e4SLinus Torvalds __set_bit(0, &new->bitmap); 2511da177e4SLinus Torvalds p = new; 2521da177e4SLinus Torvalds } 2533219b3b7SNadia Derbey rcu_assign_pointer(idp->top, p); 2541da177e4SLinus Torvalds idp->layers = layers; 255e33ac8bdSTejun Heo v = sub_alloc(idp, &id, pa); 256944ca05cSNadia Derbey if (v == IDR_NEED_TO_GROW) 2571da177e4SLinus Torvalds goto build_up; 2581da177e4SLinus Torvalds return(v); 2591da177e4SLinus Torvalds } 2601da177e4SLinus Torvalds 261e33ac8bdSTejun Heo static int idr_get_new_above_int(struct idr *idp, void *ptr, int starting_id) 262e33ac8bdSTejun Heo { 263e33ac8bdSTejun Heo struct idr_layer *pa[MAX_LEVEL]; 264e33ac8bdSTejun Heo int id; 265e33ac8bdSTejun Heo 266e33ac8bdSTejun Heo id = idr_get_empty_slot(idp, starting_id, pa); 267e33ac8bdSTejun Heo if (id >= 0) { 268e33ac8bdSTejun Heo /* 269e33ac8bdSTejun Heo * Successfully found an empty slot. Install the user 270e33ac8bdSTejun Heo * pointer and mark the slot full. 271e33ac8bdSTejun Heo */ 2723219b3b7SNadia Derbey rcu_assign_pointer(pa[0]->ary[id & IDR_MASK], 2733219b3b7SNadia Derbey (struct idr_layer *)ptr); 274e33ac8bdSTejun Heo pa[0]->count++; 275e33ac8bdSTejun Heo idr_mark_full(pa, id); 276e33ac8bdSTejun Heo } 277e33ac8bdSTejun Heo 278e33ac8bdSTejun Heo return id; 279e33ac8bdSTejun Heo } 280e33ac8bdSTejun Heo 2811da177e4SLinus Torvalds /** 2827c657f2fSJohn McCutchan * idr_get_new_above - allocate new idr entry above or equal to a start id 2831da177e4SLinus Torvalds * @idp: idr handle 2841da177e4SLinus Torvalds * @ptr: pointer you want associated with the ide 2851da177e4SLinus Torvalds * @start_id: id to start search at 2861da177e4SLinus Torvalds * @id: pointer to the allocated handle 2871da177e4SLinus Torvalds * 2881da177e4SLinus Torvalds * This is the allocate id function. It should be called with any 2891da177e4SLinus Torvalds * required locks. 2901da177e4SLinus Torvalds * 2911da177e4SLinus Torvalds * If memory is required, it will return -EAGAIN, you should unlock 2921da177e4SLinus Torvalds * and go back to the idr_pre_get() call. If the idr is full, it will 2931da177e4SLinus Torvalds * return -ENOSPC. 2941da177e4SLinus Torvalds * 295b098161bSLi Zefan * @id returns a value in the range @starting_id ... 0x7fffffff 2961da177e4SLinus Torvalds */ 2971da177e4SLinus Torvalds int idr_get_new_above(struct idr *idp, void *ptr, int starting_id, int *id) 2981da177e4SLinus Torvalds { 2991da177e4SLinus Torvalds int rv; 300e15ae2ddSJesper Juhl 3011da177e4SLinus Torvalds rv = idr_get_new_above_int(idp, ptr, starting_id); 3021da177e4SLinus Torvalds /* 3031da177e4SLinus Torvalds * This is a cheap hack until the IDR code can be fixed to 3041da177e4SLinus Torvalds * return proper error values. 3051da177e4SLinus Torvalds */ 306944ca05cSNadia Derbey if (rv < 0) 307944ca05cSNadia Derbey return _idr_rc_to_errno(rv); 3081da177e4SLinus Torvalds *id = rv; 3091da177e4SLinus Torvalds return 0; 3101da177e4SLinus Torvalds } 3111da177e4SLinus Torvalds EXPORT_SYMBOL(idr_get_new_above); 3121da177e4SLinus Torvalds 3131da177e4SLinus Torvalds /** 3141da177e4SLinus Torvalds * idr_get_new - allocate new idr entry 3151da177e4SLinus Torvalds * @idp: idr handle 3161da177e4SLinus Torvalds * @ptr: pointer you want associated with the ide 3171da177e4SLinus Torvalds * @id: pointer to the allocated handle 3181da177e4SLinus Torvalds * 3191da177e4SLinus Torvalds * This is the allocate id function. It should be called with any 3201da177e4SLinus Torvalds * required locks. 3211da177e4SLinus Torvalds * 3221da177e4SLinus Torvalds * If memory is required, it will return -EAGAIN, you should unlock 3231da177e4SLinus Torvalds * and go back to the idr_pre_get() call. If the idr is full, it will 3241da177e4SLinus Torvalds * return -ENOSPC. 3251da177e4SLinus Torvalds * 3261da177e4SLinus Torvalds * @id returns a value in the range 0 ... 0x7fffffff 3271da177e4SLinus Torvalds */ 3281da177e4SLinus Torvalds int idr_get_new(struct idr *idp, void *ptr, int *id) 3291da177e4SLinus Torvalds { 3301da177e4SLinus Torvalds int rv; 331e15ae2ddSJesper Juhl 3321da177e4SLinus Torvalds rv = idr_get_new_above_int(idp, ptr, 0); 3331da177e4SLinus Torvalds /* 3341da177e4SLinus Torvalds * This is a cheap hack until the IDR code can be fixed to 3351da177e4SLinus Torvalds * return proper error values. 3361da177e4SLinus Torvalds */ 337944ca05cSNadia Derbey if (rv < 0) 338944ca05cSNadia Derbey return _idr_rc_to_errno(rv); 3391da177e4SLinus Torvalds *id = rv; 3401da177e4SLinus Torvalds return 0; 3411da177e4SLinus Torvalds } 3421da177e4SLinus Torvalds EXPORT_SYMBOL(idr_get_new); 3431da177e4SLinus Torvalds 3441da177e4SLinus Torvalds static void idr_remove_warning(int id) 3451da177e4SLinus Torvalds { 346f098ad65SNadia Derbey printk(KERN_WARNING 347f098ad65SNadia Derbey "idr_remove called for id=%d which is not allocated.\n", id); 3481da177e4SLinus Torvalds dump_stack(); 3491da177e4SLinus Torvalds } 3501da177e4SLinus Torvalds 3511da177e4SLinus Torvalds static void sub_remove(struct idr *idp, int shift, int id) 3521da177e4SLinus Torvalds { 3531da177e4SLinus Torvalds struct idr_layer *p = idp->top; 3541da177e4SLinus Torvalds struct idr_layer **pa[MAX_LEVEL]; 3551da177e4SLinus Torvalds struct idr_layer ***paa = &pa[0]; 356cf481c20SNadia Derbey struct idr_layer *to_free; 3571da177e4SLinus Torvalds int n; 3581da177e4SLinus Torvalds 3591da177e4SLinus Torvalds *paa = NULL; 3601da177e4SLinus Torvalds *++paa = &idp->top; 3611da177e4SLinus Torvalds 3621da177e4SLinus Torvalds while ((shift > 0) && p) { 3631da177e4SLinus Torvalds n = (id >> shift) & IDR_MASK; 3641da177e4SLinus Torvalds __clear_bit(n, &p->bitmap); 3651da177e4SLinus Torvalds *++paa = &p->ary[n]; 3661da177e4SLinus Torvalds p = p->ary[n]; 3671da177e4SLinus Torvalds shift -= IDR_BITS; 3681da177e4SLinus Torvalds } 3691da177e4SLinus Torvalds n = id & IDR_MASK; 3701da177e4SLinus Torvalds if (likely(p != NULL && test_bit(n, &p->bitmap))){ 3711da177e4SLinus Torvalds __clear_bit(n, &p->bitmap); 372cf481c20SNadia Derbey rcu_assign_pointer(p->ary[n], NULL); 373cf481c20SNadia Derbey to_free = NULL; 3741da177e4SLinus Torvalds while(*paa && ! --((**paa)->count)){ 375cf481c20SNadia Derbey if (to_free) 376cf481c20SNadia Derbey free_layer(to_free); 377cf481c20SNadia Derbey to_free = **paa; 3781da177e4SLinus Torvalds **paa-- = NULL; 3791da177e4SLinus Torvalds } 3801da177e4SLinus Torvalds if (!*paa) 3811da177e4SLinus Torvalds idp->layers = 0; 382cf481c20SNadia Derbey if (to_free) 383cf481c20SNadia Derbey free_layer(to_free); 384e15ae2ddSJesper Juhl } else 3851da177e4SLinus Torvalds idr_remove_warning(id); 3861da177e4SLinus Torvalds } 3871da177e4SLinus Torvalds 3881da177e4SLinus Torvalds /** 3891da177e4SLinus Torvalds * idr_remove - remove the given id and free it's slot 39072fd4a35SRobert P. J. Day * @idp: idr handle 39172fd4a35SRobert P. J. Day * @id: unique key 3921da177e4SLinus Torvalds */ 3931da177e4SLinus Torvalds void idr_remove(struct idr *idp, int id) 3941da177e4SLinus Torvalds { 3951da177e4SLinus Torvalds struct idr_layer *p; 396cf481c20SNadia Derbey struct idr_layer *to_free; 3971da177e4SLinus Torvalds 3981da177e4SLinus Torvalds /* Mask off upper bits we don't use for the search. */ 3991da177e4SLinus Torvalds id &= MAX_ID_MASK; 4001da177e4SLinus Torvalds 4011da177e4SLinus Torvalds sub_remove(idp, (idp->layers - 1) * IDR_BITS, id); 402e15ae2ddSJesper Juhl if (idp->top && idp->top->count == 1 && (idp->layers > 1) && 403cf481c20SNadia Derbey idp->top->ary[0]) { 404cf481c20SNadia Derbey /* 405cf481c20SNadia Derbey * Single child at leftmost slot: we can shrink the tree. 406cf481c20SNadia Derbey * This level is not needed anymore since when layers are 407cf481c20SNadia Derbey * inserted, they are inserted at the top of the existing 408cf481c20SNadia Derbey * tree. 409cf481c20SNadia Derbey */ 410cf481c20SNadia Derbey to_free = idp->top; 4111da177e4SLinus Torvalds p = idp->top->ary[0]; 412cf481c20SNadia Derbey rcu_assign_pointer(idp->top, p); 4131da177e4SLinus Torvalds --idp->layers; 414cf481c20SNadia Derbey to_free->bitmap = to_free->count = 0; 415cf481c20SNadia Derbey free_layer(to_free); 4161da177e4SLinus Torvalds } 4171da177e4SLinus Torvalds while (idp->id_free_cnt >= IDR_FREE_MAX) { 4184ae53789SNadia Derbey p = get_from_free_list(idp); 419cf481c20SNadia Derbey /* 420cf481c20SNadia Derbey * Note: we don't call the rcu callback here, since the only 421cf481c20SNadia Derbey * layers that fall into the freelist are those that have been 422cf481c20SNadia Derbey * preallocated. 423cf481c20SNadia Derbey */ 4241da177e4SLinus Torvalds kmem_cache_free(idr_layer_cache, p); 4251da177e4SLinus Torvalds } 426af8e2a4cSNadia Derbey return; 4271da177e4SLinus Torvalds } 4281da177e4SLinus Torvalds EXPORT_SYMBOL(idr_remove); 4291da177e4SLinus Torvalds 4301da177e4SLinus Torvalds /** 43123936cc0SKristian Hoegsberg * idr_remove_all - remove all ids from the given idr tree 43223936cc0SKristian Hoegsberg * @idp: idr handle 43323936cc0SKristian Hoegsberg * 43423936cc0SKristian Hoegsberg * idr_destroy() only frees up unused, cached idp_layers, but this 43523936cc0SKristian Hoegsberg * function will remove all id mappings and leave all idp_layers 43623936cc0SKristian Hoegsberg * unused. 43723936cc0SKristian Hoegsberg * 43823936cc0SKristian Hoegsberg * A typical clean-up sequence for objects stored in an idr tree, will 43923936cc0SKristian Hoegsberg * use idr_for_each() to free all objects, if necessay, then 44023936cc0SKristian Hoegsberg * idr_remove_all() to remove all ids, and idr_destroy() to free 44123936cc0SKristian Hoegsberg * up the cached idr_layers. 44223936cc0SKristian Hoegsberg */ 44323936cc0SKristian Hoegsberg void idr_remove_all(struct idr *idp) 44423936cc0SKristian Hoegsberg { 4456ace06dcSOleg Nesterov int n, id, max; 44623936cc0SKristian Hoegsberg struct idr_layer *p; 44723936cc0SKristian Hoegsberg struct idr_layer *pa[MAX_LEVEL]; 44823936cc0SKristian Hoegsberg struct idr_layer **paa = &pa[0]; 44923936cc0SKristian Hoegsberg 45023936cc0SKristian Hoegsberg n = idp->layers * IDR_BITS; 45123936cc0SKristian Hoegsberg p = idp->top; 4521b23336aSPaul E. McKenney rcu_assign_pointer(idp->top, NULL); 45323936cc0SKristian Hoegsberg max = 1 << n; 45423936cc0SKristian Hoegsberg 45523936cc0SKristian Hoegsberg id = 0; 4566ace06dcSOleg Nesterov while (id < max) { 45723936cc0SKristian Hoegsberg while (n > IDR_BITS && p) { 45823936cc0SKristian Hoegsberg n -= IDR_BITS; 45923936cc0SKristian Hoegsberg *paa++ = p; 46023936cc0SKristian Hoegsberg p = p->ary[(id >> n) & IDR_MASK]; 46123936cc0SKristian Hoegsberg } 46223936cc0SKristian Hoegsberg 46323936cc0SKristian Hoegsberg id += 1 << n; 46423936cc0SKristian Hoegsberg while (n < fls(id)) { 465cf481c20SNadia Derbey if (p) 466cf481c20SNadia Derbey free_layer(p); 46723936cc0SKristian Hoegsberg n += IDR_BITS; 46823936cc0SKristian Hoegsberg p = *--paa; 46923936cc0SKristian Hoegsberg } 47023936cc0SKristian Hoegsberg } 47123936cc0SKristian Hoegsberg idp->layers = 0; 47223936cc0SKristian Hoegsberg } 47323936cc0SKristian Hoegsberg EXPORT_SYMBOL(idr_remove_all); 47423936cc0SKristian Hoegsberg 47523936cc0SKristian Hoegsberg /** 4768d3b3591SAndrew Morton * idr_destroy - release all cached layers within an idr tree 4778d3b3591SAndrew Morton * idp: idr handle 4788d3b3591SAndrew Morton */ 4798d3b3591SAndrew Morton void idr_destroy(struct idr *idp) 4808d3b3591SAndrew Morton { 4818d3b3591SAndrew Morton while (idp->id_free_cnt) { 4824ae53789SNadia Derbey struct idr_layer *p = get_from_free_list(idp); 4838d3b3591SAndrew Morton kmem_cache_free(idr_layer_cache, p); 4848d3b3591SAndrew Morton } 4858d3b3591SAndrew Morton } 4868d3b3591SAndrew Morton EXPORT_SYMBOL(idr_destroy); 4878d3b3591SAndrew Morton 4888d3b3591SAndrew Morton /** 4891da177e4SLinus Torvalds * idr_find - return pointer for given id 4901da177e4SLinus Torvalds * @idp: idr handle 4911da177e4SLinus Torvalds * @id: lookup key 4921da177e4SLinus Torvalds * 4931da177e4SLinus Torvalds * Return the pointer given the id it has been registered with. A %NULL 4941da177e4SLinus Torvalds * return indicates that @id is not valid or you passed %NULL in 4951da177e4SLinus Torvalds * idr_get_new(). 4961da177e4SLinus Torvalds * 497f9c46d6eSNadia Derbey * This function can be called under rcu_read_lock(), given that the leaf 498f9c46d6eSNadia Derbey * pointers lifetimes are correctly managed. 4991da177e4SLinus Torvalds */ 5001da177e4SLinus Torvalds void *idr_find(struct idr *idp, int id) 5011da177e4SLinus Torvalds { 5021da177e4SLinus Torvalds int n; 5031da177e4SLinus Torvalds struct idr_layer *p; 5041da177e4SLinus Torvalds 505f9c46d6eSNadia Derbey p = rcu_dereference(idp->top); 5066ff2d39bSManfred Spraul if (!p) 5076ff2d39bSManfred Spraul return NULL; 5086ff2d39bSManfred Spraul n = (p->layer+1) * IDR_BITS; 5091da177e4SLinus Torvalds 5101da177e4SLinus Torvalds /* Mask off upper bits we don't use for the search. */ 5111da177e4SLinus Torvalds id &= MAX_ID_MASK; 5121da177e4SLinus Torvalds 5131da177e4SLinus Torvalds if (id >= (1 << n)) 5141da177e4SLinus Torvalds return NULL; 5156ff2d39bSManfred Spraul BUG_ON(n == 0); 5161da177e4SLinus Torvalds 5171da177e4SLinus Torvalds while (n > 0 && p) { 5181da177e4SLinus Torvalds n -= IDR_BITS; 5196ff2d39bSManfred Spraul BUG_ON(n != p->layer*IDR_BITS); 520f9c46d6eSNadia Derbey p = rcu_dereference(p->ary[(id >> n) & IDR_MASK]); 5211da177e4SLinus Torvalds } 5221da177e4SLinus Torvalds return((void *)p); 5231da177e4SLinus Torvalds } 5241da177e4SLinus Torvalds EXPORT_SYMBOL(idr_find); 5251da177e4SLinus Torvalds 5265806f07cSJeff Mahoney /** 52796d7fa42SKristian Hoegsberg * idr_for_each - iterate through all stored pointers 52896d7fa42SKristian Hoegsberg * @idp: idr handle 52996d7fa42SKristian Hoegsberg * @fn: function to be called for each pointer 53096d7fa42SKristian Hoegsberg * @data: data passed back to callback function 53196d7fa42SKristian Hoegsberg * 53296d7fa42SKristian Hoegsberg * Iterate over the pointers registered with the given idr. The 53396d7fa42SKristian Hoegsberg * callback function will be called for each pointer currently 53496d7fa42SKristian Hoegsberg * registered, passing the id, the pointer and the data pointer passed 53596d7fa42SKristian Hoegsberg * to this function. It is not safe to modify the idr tree while in 53696d7fa42SKristian Hoegsberg * the callback, so functions such as idr_get_new and idr_remove are 53796d7fa42SKristian Hoegsberg * not allowed. 53896d7fa42SKristian Hoegsberg * 53996d7fa42SKristian Hoegsberg * We check the return of @fn each time. If it returns anything other 54096d7fa42SKristian Hoegsberg * than 0, we break out and return that value. 54196d7fa42SKristian Hoegsberg * 54296d7fa42SKristian Hoegsberg * The caller must serialize idr_for_each() vs idr_get_new() and idr_remove(). 54396d7fa42SKristian Hoegsberg */ 54496d7fa42SKristian Hoegsberg int idr_for_each(struct idr *idp, 54596d7fa42SKristian Hoegsberg int (*fn)(int id, void *p, void *data), void *data) 54696d7fa42SKristian Hoegsberg { 54796d7fa42SKristian Hoegsberg int n, id, max, error = 0; 54896d7fa42SKristian Hoegsberg struct idr_layer *p; 54996d7fa42SKristian Hoegsberg struct idr_layer *pa[MAX_LEVEL]; 55096d7fa42SKristian Hoegsberg struct idr_layer **paa = &pa[0]; 55196d7fa42SKristian Hoegsberg 55296d7fa42SKristian Hoegsberg n = idp->layers * IDR_BITS; 553f9c46d6eSNadia Derbey p = rcu_dereference(idp->top); 55496d7fa42SKristian Hoegsberg max = 1 << n; 55596d7fa42SKristian Hoegsberg 55696d7fa42SKristian Hoegsberg id = 0; 55796d7fa42SKristian Hoegsberg while (id < max) { 55896d7fa42SKristian Hoegsberg while (n > 0 && p) { 55996d7fa42SKristian Hoegsberg n -= IDR_BITS; 56096d7fa42SKristian Hoegsberg *paa++ = p; 561f9c46d6eSNadia Derbey p = rcu_dereference(p->ary[(id >> n) & IDR_MASK]); 56296d7fa42SKristian Hoegsberg } 56396d7fa42SKristian Hoegsberg 56496d7fa42SKristian Hoegsberg if (p) { 56596d7fa42SKristian Hoegsberg error = fn(id, (void *)p, data); 56696d7fa42SKristian Hoegsberg if (error) 56796d7fa42SKristian Hoegsberg break; 56896d7fa42SKristian Hoegsberg } 56996d7fa42SKristian Hoegsberg 57096d7fa42SKristian Hoegsberg id += 1 << n; 57196d7fa42SKristian Hoegsberg while (n < fls(id)) { 57296d7fa42SKristian Hoegsberg n += IDR_BITS; 57396d7fa42SKristian Hoegsberg p = *--paa; 57496d7fa42SKristian Hoegsberg } 57596d7fa42SKristian Hoegsberg } 57696d7fa42SKristian Hoegsberg 57796d7fa42SKristian Hoegsberg return error; 57896d7fa42SKristian Hoegsberg } 57996d7fa42SKristian Hoegsberg EXPORT_SYMBOL(idr_for_each); 58096d7fa42SKristian Hoegsberg 58196d7fa42SKristian Hoegsberg /** 5825806f07cSJeff Mahoney * idr_replace - replace pointer for given id 5835806f07cSJeff Mahoney * @idp: idr handle 5845806f07cSJeff Mahoney * @ptr: pointer you want associated with the id 5855806f07cSJeff Mahoney * @id: lookup key 5865806f07cSJeff Mahoney * 5875806f07cSJeff Mahoney * Replace the pointer registered with an id and return the old value. 5885806f07cSJeff Mahoney * A -ENOENT return indicates that @id was not found. 5895806f07cSJeff Mahoney * A -EINVAL return indicates that @id was not within valid constraints. 5905806f07cSJeff Mahoney * 591cf481c20SNadia Derbey * The caller must serialize with writers. 5925806f07cSJeff Mahoney */ 5935806f07cSJeff Mahoney void *idr_replace(struct idr *idp, void *ptr, int id) 5945806f07cSJeff Mahoney { 5955806f07cSJeff Mahoney int n; 5965806f07cSJeff Mahoney struct idr_layer *p, *old_p; 5975806f07cSJeff Mahoney 5985806f07cSJeff Mahoney p = idp->top; 5996ff2d39bSManfred Spraul if (!p) 6006ff2d39bSManfred Spraul return ERR_PTR(-EINVAL); 6016ff2d39bSManfred Spraul 6026ff2d39bSManfred Spraul n = (p->layer+1) * IDR_BITS; 6035806f07cSJeff Mahoney 6045806f07cSJeff Mahoney id &= MAX_ID_MASK; 6055806f07cSJeff Mahoney 6065806f07cSJeff Mahoney if (id >= (1 << n)) 6075806f07cSJeff Mahoney return ERR_PTR(-EINVAL); 6085806f07cSJeff Mahoney 6095806f07cSJeff Mahoney n -= IDR_BITS; 6105806f07cSJeff Mahoney while ((n > 0) && p) { 6115806f07cSJeff Mahoney p = p->ary[(id >> n) & IDR_MASK]; 6125806f07cSJeff Mahoney n -= IDR_BITS; 6135806f07cSJeff Mahoney } 6145806f07cSJeff Mahoney 6155806f07cSJeff Mahoney n = id & IDR_MASK; 6165806f07cSJeff Mahoney if (unlikely(p == NULL || !test_bit(n, &p->bitmap))) 6175806f07cSJeff Mahoney return ERR_PTR(-ENOENT); 6185806f07cSJeff Mahoney 6195806f07cSJeff Mahoney old_p = p->ary[n]; 620cf481c20SNadia Derbey rcu_assign_pointer(p->ary[n], ptr); 6215806f07cSJeff Mahoney 6225806f07cSJeff Mahoney return old_p; 6235806f07cSJeff Mahoney } 6245806f07cSJeff Mahoney EXPORT_SYMBOL(idr_replace); 6255806f07cSJeff Mahoney 626199f0ca5SAkinobu Mita void __init idr_init_cache(void) 6271da177e4SLinus Torvalds { 6281da177e4SLinus Torvalds idr_layer_cache = kmem_cache_create("idr_layer_cache", 6295b019e99SAndrew Morton sizeof(struct idr_layer), 0, SLAB_PANIC, NULL); 6301da177e4SLinus Torvalds } 6311da177e4SLinus Torvalds 6321da177e4SLinus Torvalds /** 6331da177e4SLinus Torvalds * idr_init - initialize idr handle 6341da177e4SLinus Torvalds * @idp: idr handle 6351da177e4SLinus Torvalds * 6361da177e4SLinus Torvalds * This function is use to set up the handle (@idp) that you will pass 6371da177e4SLinus Torvalds * to the rest of the functions. 6381da177e4SLinus Torvalds */ 6391da177e4SLinus Torvalds void idr_init(struct idr *idp) 6401da177e4SLinus Torvalds { 6411da177e4SLinus Torvalds memset(idp, 0, sizeof(struct idr)); 6421da177e4SLinus Torvalds spin_lock_init(&idp->lock); 6431da177e4SLinus Torvalds } 6441da177e4SLinus Torvalds EXPORT_SYMBOL(idr_init); 64572dba584STejun Heo 64672dba584STejun Heo 64772dba584STejun Heo /* 64872dba584STejun Heo * IDA - IDR based ID allocator 64972dba584STejun Heo * 65072dba584STejun Heo * this is id allocator without id -> pointer translation. Memory 65172dba584STejun Heo * usage is much lower than full blown idr because each id only 65272dba584STejun Heo * occupies a bit. ida uses a custom leaf node which contains 65372dba584STejun Heo * IDA_BITMAP_BITS slots. 65472dba584STejun Heo * 65572dba584STejun Heo * 2007-04-25 written by Tejun Heo <htejun@gmail.com> 65672dba584STejun Heo */ 65772dba584STejun Heo 65872dba584STejun Heo static void free_bitmap(struct ida *ida, struct ida_bitmap *bitmap) 65972dba584STejun Heo { 66072dba584STejun Heo unsigned long flags; 66172dba584STejun Heo 66272dba584STejun Heo if (!ida->free_bitmap) { 66372dba584STejun Heo spin_lock_irqsave(&ida->idr.lock, flags); 66472dba584STejun Heo if (!ida->free_bitmap) { 66572dba584STejun Heo ida->free_bitmap = bitmap; 66672dba584STejun Heo bitmap = NULL; 66772dba584STejun Heo } 66872dba584STejun Heo spin_unlock_irqrestore(&ida->idr.lock, flags); 66972dba584STejun Heo } 67072dba584STejun Heo 67172dba584STejun Heo kfree(bitmap); 67272dba584STejun Heo } 67372dba584STejun Heo 67472dba584STejun Heo /** 67572dba584STejun Heo * ida_pre_get - reserve resources for ida allocation 67672dba584STejun Heo * @ida: ida handle 67772dba584STejun Heo * @gfp_mask: memory allocation flag 67872dba584STejun Heo * 67972dba584STejun Heo * This function should be called prior to locking and calling the 68072dba584STejun Heo * following function. It preallocates enough memory to satisfy the 68172dba584STejun Heo * worst possible allocation. 68272dba584STejun Heo * 68372dba584STejun Heo * If the system is REALLY out of memory this function returns 0, 68472dba584STejun Heo * otherwise 1. 68572dba584STejun Heo */ 68672dba584STejun Heo int ida_pre_get(struct ida *ida, gfp_t gfp_mask) 68772dba584STejun Heo { 68872dba584STejun Heo /* allocate idr_layers */ 68972dba584STejun Heo if (!idr_pre_get(&ida->idr, gfp_mask)) 69072dba584STejun Heo return 0; 69172dba584STejun Heo 69272dba584STejun Heo /* allocate free_bitmap */ 69372dba584STejun Heo if (!ida->free_bitmap) { 69472dba584STejun Heo struct ida_bitmap *bitmap; 69572dba584STejun Heo 69672dba584STejun Heo bitmap = kmalloc(sizeof(struct ida_bitmap), gfp_mask); 69772dba584STejun Heo if (!bitmap) 69872dba584STejun Heo return 0; 69972dba584STejun Heo 70072dba584STejun Heo free_bitmap(ida, bitmap); 70172dba584STejun Heo } 70272dba584STejun Heo 70372dba584STejun Heo return 1; 70472dba584STejun Heo } 70572dba584STejun Heo EXPORT_SYMBOL(ida_pre_get); 70672dba584STejun Heo 70772dba584STejun Heo /** 70872dba584STejun Heo * ida_get_new_above - allocate new ID above or equal to a start id 70972dba584STejun Heo * @ida: ida handle 71072dba584STejun Heo * @staring_id: id to start search at 71172dba584STejun Heo * @p_id: pointer to the allocated handle 71272dba584STejun Heo * 71372dba584STejun Heo * Allocate new ID above or equal to @ida. It should be called with 71472dba584STejun Heo * any required locks. 71572dba584STejun Heo * 71672dba584STejun Heo * If memory is required, it will return -EAGAIN, you should unlock 71772dba584STejun Heo * and go back to the ida_pre_get() call. If the ida is full, it will 71872dba584STejun Heo * return -ENOSPC. 71972dba584STejun Heo * 720b098161bSLi Zefan * @p_id returns a value in the range @starting_id ... 0x7fffffff. 72172dba584STejun Heo */ 72272dba584STejun Heo int ida_get_new_above(struct ida *ida, int starting_id, int *p_id) 72372dba584STejun Heo { 72472dba584STejun Heo struct idr_layer *pa[MAX_LEVEL]; 72572dba584STejun Heo struct ida_bitmap *bitmap; 72672dba584STejun Heo unsigned long flags; 72772dba584STejun Heo int idr_id = starting_id / IDA_BITMAP_BITS; 72872dba584STejun Heo int offset = starting_id % IDA_BITMAP_BITS; 72972dba584STejun Heo int t, id; 73072dba584STejun Heo 73172dba584STejun Heo restart: 73272dba584STejun Heo /* get vacant slot */ 73372dba584STejun Heo t = idr_get_empty_slot(&ida->idr, idr_id, pa); 734944ca05cSNadia Derbey if (t < 0) 735944ca05cSNadia Derbey return _idr_rc_to_errno(t); 73672dba584STejun Heo 73772dba584STejun Heo if (t * IDA_BITMAP_BITS >= MAX_ID_BIT) 73872dba584STejun Heo return -ENOSPC; 73972dba584STejun Heo 74072dba584STejun Heo if (t != idr_id) 74172dba584STejun Heo offset = 0; 74272dba584STejun Heo idr_id = t; 74372dba584STejun Heo 74472dba584STejun Heo /* if bitmap isn't there, create a new one */ 74572dba584STejun Heo bitmap = (void *)pa[0]->ary[idr_id & IDR_MASK]; 74672dba584STejun Heo if (!bitmap) { 74772dba584STejun Heo spin_lock_irqsave(&ida->idr.lock, flags); 74872dba584STejun Heo bitmap = ida->free_bitmap; 74972dba584STejun Heo ida->free_bitmap = NULL; 75072dba584STejun Heo spin_unlock_irqrestore(&ida->idr.lock, flags); 75172dba584STejun Heo 75272dba584STejun Heo if (!bitmap) 75372dba584STejun Heo return -EAGAIN; 75472dba584STejun Heo 75572dba584STejun Heo memset(bitmap, 0, sizeof(struct ida_bitmap)); 7563219b3b7SNadia Derbey rcu_assign_pointer(pa[0]->ary[idr_id & IDR_MASK], 7573219b3b7SNadia Derbey (void *)bitmap); 75872dba584STejun Heo pa[0]->count++; 75972dba584STejun Heo } 76072dba584STejun Heo 76172dba584STejun Heo /* lookup for empty slot */ 76272dba584STejun Heo t = find_next_zero_bit(bitmap->bitmap, IDA_BITMAP_BITS, offset); 76372dba584STejun Heo if (t == IDA_BITMAP_BITS) { 76472dba584STejun Heo /* no empty slot after offset, continue to the next chunk */ 76572dba584STejun Heo idr_id++; 76672dba584STejun Heo offset = 0; 76772dba584STejun Heo goto restart; 76872dba584STejun Heo } 76972dba584STejun Heo 77072dba584STejun Heo id = idr_id * IDA_BITMAP_BITS + t; 77172dba584STejun Heo if (id >= MAX_ID_BIT) 77272dba584STejun Heo return -ENOSPC; 77372dba584STejun Heo 77472dba584STejun Heo __set_bit(t, bitmap->bitmap); 77572dba584STejun Heo if (++bitmap->nr_busy == IDA_BITMAP_BITS) 77672dba584STejun Heo idr_mark_full(pa, idr_id); 77772dba584STejun Heo 77872dba584STejun Heo *p_id = id; 77972dba584STejun Heo 78072dba584STejun Heo /* Each leaf node can handle nearly a thousand slots and the 78172dba584STejun Heo * whole idea of ida is to have small memory foot print. 78272dba584STejun Heo * Throw away extra resources one by one after each successful 78372dba584STejun Heo * allocation. 78472dba584STejun Heo */ 78572dba584STejun Heo if (ida->idr.id_free_cnt || ida->free_bitmap) { 7864ae53789SNadia Derbey struct idr_layer *p = get_from_free_list(&ida->idr); 78772dba584STejun Heo if (p) 78872dba584STejun Heo kmem_cache_free(idr_layer_cache, p); 78972dba584STejun Heo } 79072dba584STejun Heo 79172dba584STejun Heo return 0; 79272dba584STejun Heo } 79372dba584STejun Heo EXPORT_SYMBOL(ida_get_new_above); 79472dba584STejun Heo 79572dba584STejun Heo /** 79672dba584STejun Heo * ida_get_new - allocate new ID 79772dba584STejun Heo * @ida: idr handle 79872dba584STejun Heo * @p_id: pointer to the allocated handle 79972dba584STejun Heo * 80072dba584STejun Heo * Allocate new ID. It should be called with any required locks. 80172dba584STejun Heo * 80272dba584STejun Heo * If memory is required, it will return -EAGAIN, you should unlock 80372dba584STejun Heo * and go back to the idr_pre_get() call. If the idr is full, it will 80472dba584STejun Heo * return -ENOSPC. 80572dba584STejun Heo * 80672dba584STejun Heo * @id returns a value in the range 0 ... 0x7fffffff. 80772dba584STejun Heo */ 80872dba584STejun Heo int ida_get_new(struct ida *ida, int *p_id) 80972dba584STejun Heo { 81072dba584STejun Heo return ida_get_new_above(ida, 0, p_id); 81172dba584STejun Heo } 81272dba584STejun Heo EXPORT_SYMBOL(ida_get_new); 81372dba584STejun Heo 81472dba584STejun Heo /** 81572dba584STejun Heo * ida_remove - remove the given ID 81672dba584STejun Heo * @ida: ida handle 81772dba584STejun Heo * @id: ID to free 81872dba584STejun Heo */ 81972dba584STejun Heo void ida_remove(struct ida *ida, int id) 82072dba584STejun Heo { 82172dba584STejun Heo struct idr_layer *p = ida->idr.top; 82272dba584STejun Heo int shift = (ida->idr.layers - 1) * IDR_BITS; 82372dba584STejun Heo int idr_id = id / IDA_BITMAP_BITS; 82472dba584STejun Heo int offset = id % IDA_BITMAP_BITS; 82572dba584STejun Heo int n; 82672dba584STejun Heo struct ida_bitmap *bitmap; 82772dba584STejun Heo 82872dba584STejun Heo /* clear full bits while looking up the leaf idr_layer */ 82972dba584STejun Heo while ((shift > 0) && p) { 83072dba584STejun Heo n = (idr_id >> shift) & IDR_MASK; 83172dba584STejun Heo __clear_bit(n, &p->bitmap); 83272dba584STejun Heo p = p->ary[n]; 83372dba584STejun Heo shift -= IDR_BITS; 83472dba584STejun Heo } 83572dba584STejun Heo 83672dba584STejun Heo if (p == NULL) 83772dba584STejun Heo goto err; 83872dba584STejun Heo 83972dba584STejun Heo n = idr_id & IDR_MASK; 84072dba584STejun Heo __clear_bit(n, &p->bitmap); 84172dba584STejun Heo 84272dba584STejun Heo bitmap = (void *)p->ary[n]; 84372dba584STejun Heo if (!test_bit(offset, bitmap->bitmap)) 84472dba584STejun Heo goto err; 84572dba584STejun Heo 84672dba584STejun Heo /* update bitmap and remove it if empty */ 84772dba584STejun Heo __clear_bit(offset, bitmap->bitmap); 84872dba584STejun Heo if (--bitmap->nr_busy == 0) { 84972dba584STejun Heo __set_bit(n, &p->bitmap); /* to please idr_remove() */ 85072dba584STejun Heo idr_remove(&ida->idr, idr_id); 85172dba584STejun Heo free_bitmap(ida, bitmap); 85272dba584STejun Heo } 85372dba584STejun Heo 85472dba584STejun Heo return; 85572dba584STejun Heo 85672dba584STejun Heo err: 85772dba584STejun Heo printk(KERN_WARNING 85872dba584STejun Heo "ida_remove called for id=%d which is not allocated.\n", id); 85972dba584STejun Heo } 86072dba584STejun Heo EXPORT_SYMBOL(ida_remove); 86172dba584STejun Heo 86272dba584STejun Heo /** 86372dba584STejun Heo * ida_destroy - release all cached layers within an ida tree 86472dba584STejun Heo * ida: ida handle 86572dba584STejun Heo */ 86672dba584STejun Heo void ida_destroy(struct ida *ida) 86772dba584STejun Heo { 86872dba584STejun Heo idr_destroy(&ida->idr); 86972dba584STejun Heo kfree(ida->free_bitmap); 87072dba584STejun Heo } 87172dba584STejun Heo EXPORT_SYMBOL(ida_destroy); 87272dba584STejun Heo 87372dba584STejun Heo /** 87472dba584STejun Heo * ida_init - initialize ida handle 87572dba584STejun Heo * @ida: ida handle 87672dba584STejun Heo * 87772dba584STejun Heo * This function is use to set up the handle (@ida) that you will pass 87872dba584STejun Heo * to the rest of the functions. 87972dba584STejun Heo */ 88072dba584STejun Heo void ida_init(struct ida *ida) 88172dba584STejun Heo { 88272dba584STejun Heo memset(ida, 0, sizeof(struct ida)); 88372dba584STejun Heo idr_init(&ida->idr); 88472dba584STejun Heo 88572dba584STejun Heo } 88672dba584STejun Heo EXPORT_SYMBOL(ida_init); 887