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 /** 10956083ab1SRandy Dunlap * idr_pre_get - reserve resources for idr allocation 1101da177e4SLinus Torvalds * @idp: idr handle 1111da177e4SLinus Torvalds * @gfp_mask: memory allocation flags 1121da177e4SLinus Torvalds * 113066a9be6SNaohiro Aota * This function should be called prior to calling the idr_get_new* functions. 114066a9be6SNaohiro Aota * It preallocates enough memory to satisfy the worst possible allocation. The 115066a9be6SNaohiro Aota * caller should pass in GFP_KERNEL if possible. This of course requires that 116066a9be6SNaohiro Aota * no spinning locks be held. 1171da177e4SLinus Torvalds * 11856083ab1SRandy Dunlap * If the system is REALLY out of memory this function returns %0, 11956083ab1SRandy Dunlap * otherwise %1. 1201da177e4SLinus Torvalds */ 121fd4f2df2SAl Viro int idr_pre_get(struct idr *idp, gfp_t gfp_mask) 1221da177e4SLinus Torvalds { 1231da177e4SLinus Torvalds while (idp->id_free_cnt < IDR_FREE_MAX) { 1241da177e4SLinus Torvalds struct idr_layer *new; 1255b019e99SAndrew Morton new = kmem_cache_zalloc(idr_layer_cache, gfp_mask); 1261da177e4SLinus Torvalds if (new == NULL) 1271da177e4SLinus Torvalds return (0); 1284ae53789SNadia Derbey move_to_free_list(idp, new); 1291da177e4SLinus Torvalds } 1301da177e4SLinus Torvalds return 1; 1311da177e4SLinus Torvalds } 1321da177e4SLinus Torvalds EXPORT_SYMBOL(idr_pre_get); 1331da177e4SLinus Torvalds 134e33ac8bdSTejun Heo static int sub_alloc(struct idr *idp, int *starting_id, struct idr_layer **pa) 1351da177e4SLinus Torvalds { 1361da177e4SLinus Torvalds int n, m, sh; 1371da177e4SLinus Torvalds struct idr_layer *p, *new; 1387aae6dd8STejun Heo int l, id, oid; 1395ba25331SAl Viro unsigned long bm; 1401da177e4SLinus Torvalds 1411da177e4SLinus Torvalds id = *starting_id; 1427aae6dd8STejun Heo restart: 1431da177e4SLinus Torvalds p = idp->top; 1441da177e4SLinus Torvalds l = idp->layers; 1451da177e4SLinus Torvalds pa[l--] = NULL; 1461da177e4SLinus Torvalds while (1) { 1471da177e4SLinus Torvalds /* 1481da177e4SLinus Torvalds * We run around this while until we reach the leaf node... 1491da177e4SLinus Torvalds */ 1501da177e4SLinus Torvalds n = (id >> (IDR_BITS*l)) & IDR_MASK; 1511da177e4SLinus Torvalds bm = ~p->bitmap; 1521da177e4SLinus Torvalds m = find_next_bit(&bm, IDR_SIZE, n); 1531da177e4SLinus Torvalds if (m == IDR_SIZE) { 1541da177e4SLinus Torvalds /* no space available go back to previous layer. */ 1551da177e4SLinus Torvalds l++; 1567aae6dd8STejun Heo oid = id; 1571da177e4SLinus Torvalds id = (id | ((1 << (IDR_BITS * l)) - 1)) + 1; 1587aae6dd8STejun Heo 1597aae6dd8STejun Heo /* if already at the top layer, we need to grow */ 160d2e7276bSTejun Heo if (id >= 1 << (idp->layers * IDR_BITS)) { 1611da177e4SLinus Torvalds *starting_id = id; 162944ca05cSNadia Derbey return IDR_NEED_TO_GROW; 1631da177e4SLinus Torvalds } 164d2e7276bSTejun Heo p = pa[l]; 165d2e7276bSTejun Heo BUG_ON(!p); 1667aae6dd8STejun Heo 1677aae6dd8STejun Heo /* If we need to go up one layer, continue the 1687aae6dd8STejun Heo * loop; otherwise, restart from the top. 1697aae6dd8STejun Heo */ 1707aae6dd8STejun Heo sh = IDR_BITS * (l + 1); 1717aae6dd8STejun Heo if (oid >> sh == id >> sh) 1721da177e4SLinus Torvalds continue; 1737aae6dd8STejun Heo else 1747aae6dd8STejun Heo goto restart; 1751da177e4SLinus Torvalds } 1761da177e4SLinus Torvalds if (m != n) { 1771da177e4SLinus Torvalds sh = IDR_BITS*l; 1781da177e4SLinus Torvalds id = ((id >> sh) ^ n ^ m) << sh; 1791da177e4SLinus Torvalds } 1801da177e4SLinus Torvalds if ((id >= MAX_ID_BIT) || (id < 0)) 181944ca05cSNadia Derbey return IDR_NOMORE_SPACE; 1821da177e4SLinus Torvalds if (l == 0) 1831da177e4SLinus Torvalds break; 1841da177e4SLinus Torvalds /* 1851da177e4SLinus Torvalds * Create the layer below if it is missing. 1861da177e4SLinus Torvalds */ 1871da177e4SLinus Torvalds if (!p->ary[m]) { 1884ae53789SNadia Derbey new = get_from_free_list(idp); 1894ae53789SNadia Derbey if (!new) 1901da177e4SLinus Torvalds return -1; 1916ff2d39bSManfred Spraul new->layer = l-1; 1923219b3b7SNadia Derbey rcu_assign_pointer(p->ary[m], new); 1931da177e4SLinus Torvalds p->count++; 1941da177e4SLinus Torvalds } 1951da177e4SLinus Torvalds pa[l--] = p; 1961da177e4SLinus Torvalds p = p->ary[m]; 1971da177e4SLinus Torvalds } 198e33ac8bdSTejun Heo 199e33ac8bdSTejun Heo pa[l] = p; 200e33ac8bdSTejun Heo return id; 2011da177e4SLinus Torvalds } 2021da177e4SLinus Torvalds 203e33ac8bdSTejun Heo static int idr_get_empty_slot(struct idr *idp, int starting_id, 204e33ac8bdSTejun Heo struct idr_layer **pa) 2051da177e4SLinus Torvalds { 2061da177e4SLinus Torvalds struct idr_layer *p, *new; 2071da177e4SLinus Torvalds int layers, v, id; 208c259cc28SRoland Dreier unsigned long flags; 2091da177e4SLinus Torvalds 2101da177e4SLinus Torvalds id = starting_id; 2111da177e4SLinus Torvalds build_up: 2121da177e4SLinus Torvalds p = idp->top; 2131da177e4SLinus Torvalds layers = idp->layers; 2141da177e4SLinus Torvalds if (unlikely(!p)) { 2154ae53789SNadia Derbey if (!(p = get_from_free_list(idp))) 2161da177e4SLinus Torvalds return -1; 2176ff2d39bSManfred Spraul p->layer = 0; 2181da177e4SLinus Torvalds layers = 1; 2191da177e4SLinus Torvalds } 2201da177e4SLinus Torvalds /* 2211da177e4SLinus Torvalds * Add a new layer to the top of the tree if the requested 2221da177e4SLinus Torvalds * id is larger than the currently allocated space. 2231da177e4SLinus Torvalds */ 224589777eaSZaur Kambarov while ((layers < (MAX_LEVEL - 1)) && (id >= (1 << (layers*IDR_BITS)))) { 2251da177e4SLinus Torvalds layers++; 226711a49a0SManfred Spraul if (!p->count) { 227711a49a0SManfred Spraul /* special case: if the tree is currently empty, 228711a49a0SManfred Spraul * then we grow the tree by moving the top node 229711a49a0SManfred Spraul * upwards. 230711a49a0SManfred Spraul */ 231711a49a0SManfred Spraul p->layer++; 2321da177e4SLinus Torvalds continue; 233711a49a0SManfred Spraul } 2344ae53789SNadia Derbey if (!(new = get_from_free_list(idp))) { 2351da177e4SLinus Torvalds /* 2361da177e4SLinus Torvalds * The allocation failed. If we built part of 2371da177e4SLinus Torvalds * the structure tear it down. 2381da177e4SLinus Torvalds */ 239c259cc28SRoland Dreier spin_lock_irqsave(&idp->lock, flags); 2401da177e4SLinus Torvalds for (new = p; p && p != idp->top; new = p) { 2411da177e4SLinus Torvalds p = p->ary[0]; 2421da177e4SLinus Torvalds new->ary[0] = NULL; 2431da177e4SLinus Torvalds new->bitmap = new->count = 0; 2444ae53789SNadia Derbey __move_to_free_list(idp, new); 2451da177e4SLinus Torvalds } 246c259cc28SRoland Dreier spin_unlock_irqrestore(&idp->lock, flags); 2471da177e4SLinus Torvalds return -1; 2481da177e4SLinus Torvalds } 2491da177e4SLinus Torvalds new->ary[0] = p; 2501da177e4SLinus Torvalds new->count = 1; 2516ff2d39bSManfred Spraul new->layer = layers-1; 2521da177e4SLinus Torvalds if (p->bitmap == IDR_FULL) 2531da177e4SLinus Torvalds __set_bit(0, &new->bitmap); 2541da177e4SLinus Torvalds p = new; 2551da177e4SLinus Torvalds } 2563219b3b7SNadia Derbey rcu_assign_pointer(idp->top, p); 2571da177e4SLinus Torvalds idp->layers = layers; 258e33ac8bdSTejun Heo v = sub_alloc(idp, &id, pa); 259944ca05cSNadia Derbey if (v == IDR_NEED_TO_GROW) 2601da177e4SLinus Torvalds goto build_up; 2611da177e4SLinus Torvalds return(v); 2621da177e4SLinus Torvalds } 2631da177e4SLinus Torvalds 264e33ac8bdSTejun Heo static int idr_get_new_above_int(struct idr *idp, void *ptr, int starting_id) 265e33ac8bdSTejun Heo { 266e33ac8bdSTejun Heo struct idr_layer *pa[MAX_LEVEL]; 267e33ac8bdSTejun Heo int id; 268e33ac8bdSTejun Heo 269e33ac8bdSTejun Heo id = idr_get_empty_slot(idp, starting_id, pa); 270e33ac8bdSTejun Heo if (id >= 0) { 271e33ac8bdSTejun Heo /* 272e33ac8bdSTejun Heo * Successfully found an empty slot. Install the user 273e33ac8bdSTejun Heo * pointer and mark the slot full. 274e33ac8bdSTejun Heo */ 2753219b3b7SNadia Derbey rcu_assign_pointer(pa[0]->ary[id & IDR_MASK], 2763219b3b7SNadia Derbey (struct idr_layer *)ptr); 277e33ac8bdSTejun Heo pa[0]->count++; 278e33ac8bdSTejun Heo idr_mark_full(pa, id); 279e33ac8bdSTejun Heo } 280e33ac8bdSTejun Heo 281e33ac8bdSTejun Heo return id; 282e33ac8bdSTejun Heo } 283e33ac8bdSTejun Heo 2841da177e4SLinus Torvalds /** 2857c657f2fSJohn McCutchan * idr_get_new_above - allocate new idr entry above or equal to a start id 2861da177e4SLinus Torvalds * @idp: idr handle 28794e2bd68SThadeu Lima de Souza Cascardo * @ptr: pointer you want associated with the id 288ea24ea85SNaohiro Aota * @starting_id: id to start search at 2891da177e4SLinus Torvalds * @id: pointer to the allocated handle 2901da177e4SLinus Torvalds * 2911da177e4SLinus Torvalds * This is the allocate id function. It should be called with any 2921da177e4SLinus Torvalds * required locks. 2931da177e4SLinus Torvalds * 294066a9be6SNaohiro Aota * If allocation from IDR's private freelist fails, idr_get_new_above() will 29556083ab1SRandy Dunlap * return %-EAGAIN. The caller should retry the idr_pre_get() call to refill 296066a9be6SNaohiro Aota * IDR's preallocation and then retry the idr_get_new_above() call. 297066a9be6SNaohiro Aota * 29856083ab1SRandy Dunlap * If the idr is full idr_get_new_above() will return %-ENOSPC. 2991da177e4SLinus Torvalds * 30056083ab1SRandy Dunlap * @id returns a value in the range @starting_id ... %0x7fffffff 3011da177e4SLinus Torvalds */ 3021da177e4SLinus Torvalds int idr_get_new_above(struct idr *idp, void *ptr, int starting_id, int *id) 3031da177e4SLinus Torvalds { 3041da177e4SLinus Torvalds int rv; 305e15ae2ddSJesper Juhl 3061da177e4SLinus Torvalds rv = idr_get_new_above_int(idp, ptr, starting_id); 3071da177e4SLinus Torvalds /* 3081da177e4SLinus Torvalds * This is a cheap hack until the IDR code can be fixed to 3091da177e4SLinus Torvalds * return proper error values. 3101da177e4SLinus Torvalds */ 311944ca05cSNadia Derbey if (rv < 0) 312944ca05cSNadia Derbey return _idr_rc_to_errno(rv); 3131da177e4SLinus Torvalds *id = rv; 3141da177e4SLinus Torvalds return 0; 3151da177e4SLinus Torvalds } 3161da177e4SLinus Torvalds EXPORT_SYMBOL(idr_get_new_above); 3171da177e4SLinus Torvalds 3181da177e4SLinus Torvalds /** 3191da177e4SLinus Torvalds * idr_get_new - allocate new idr entry 3201da177e4SLinus Torvalds * @idp: idr handle 32194e2bd68SThadeu Lima de Souza Cascardo * @ptr: pointer you want associated with the id 3221da177e4SLinus Torvalds * @id: pointer to the allocated handle 3231da177e4SLinus Torvalds * 324066a9be6SNaohiro Aota * If allocation from IDR's private freelist fails, idr_get_new_above() will 32556083ab1SRandy Dunlap * return %-EAGAIN. The caller should retry the idr_pre_get() call to refill 326066a9be6SNaohiro Aota * IDR's preallocation and then retry the idr_get_new_above() call. 3271da177e4SLinus Torvalds * 32856083ab1SRandy Dunlap * If the idr is full idr_get_new_above() will return %-ENOSPC. 3291da177e4SLinus Torvalds * 33056083ab1SRandy Dunlap * @id returns a value in the range %0 ... %0x7fffffff 3311da177e4SLinus Torvalds */ 3321da177e4SLinus Torvalds int idr_get_new(struct idr *idp, void *ptr, int *id) 3331da177e4SLinus Torvalds { 3341da177e4SLinus Torvalds int rv; 335e15ae2ddSJesper Juhl 3361da177e4SLinus Torvalds rv = idr_get_new_above_int(idp, ptr, 0); 3371da177e4SLinus Torvalds /* 3381da177e4SLinus Torvalds * This is a cheap hack until the IDR code can be fixed to 3391da177e4SLinus Torvalds * return proper error values. 3401da177e4SLinus Torvalds */ 341944ca05cSNadia Derbey if (rv < 0) 342944ca05cSNadia Derbey return _idr_rc_to_errno(rv); 3431da177e4SLinus Torvalds *id = rv; 3441da177e4SLinus Torvalds return 0; 3451da177e4SLinus Torvalds } 3461da177e4SLinus Torvalds EXPORT_SYMBOL(idr_get_new); 3471da177e4SLinus Torvalds 3481da177e4SLinus Torvalds static void idr_remove_warning(int id) 3491da177e4SLinus Torvalds { 350f098ad65SNadia Derbey printk(KERN_WARNING 351f098ad65SNadia Derbey "idr_remove called for id=%d which is not allocated.\n", id); 3521da177e4SLinus Torvalds dump_stack(); 3531da177e4SLinus Torvalds } 3541da177e4SLinus Torvalds 3551da177e4SLinus Torvalds static void sub_remove(struct idr *idp, int shift, int id) 3561da177e4SLinus Torvalds { 3571da177e4SLinus Torvalds struct idr_layer *p = idp->top; 3581da177e4SLinus Torvalds struct idr_layer **pa[MAX_LEVEL]; 3591da177e4SLinus Torvalds struct idr_layer ***paa = &pa[0]; 360cf481c20SNadia Derbey struct idr_layer *to_free; 3611da177e4SLinus Torvalds int n; 3621da177e4SLinus Torvalds 3631da177e4SLinus Torvalds *paa = NULL; 3641da177e4SLinus Torvalds *++paa = &idp->top; 3651da177e4SLinus Torvalds 3661da177e4SLinus Torvalds while ((shift > 0) && p) { 3671da177e4SLinus Torvalds n = (id >> shift) & IDR_MASK; 3681da177e4SLinus Torvalds __clear_bit(n, &p->bitmap); 3691da177e4SLinus Torvalds *++paa = &p->ary[n]; 3701da177e4SLinus Torvalds p = p->ary[n]; 3711da177e4SLinus Torvalds shift -= IDR_BITS; 3721da177e4SLinus Torvalds } 3731da177e4SLinus Torvalds n = id & IDR_MASK; 3741da177e4SLinus Torvalds if (likely(p != NULL && test_bit(n, &p->bitmap))){ 3751da177e4SLinus Torvalds __clear_bit(n, &p->bitmap); 376cf481c20SNadia Derbey rcu_assign_pointer(p->ary[n], NULL); 377cf481c20SNadia Derbey to_free = NULL; 3781da177e4SLinus Torvalds while(*paa && ! --((**paa)->count)){ 379cf481c20SNadia Derbey if (to_free) 380cf481c20SNadia Derbey free_layer(to_free); 381cf481c20SNadia Derbey to_free = **paa; 3821da177e4SLinus Torvalds **paa-- = NULL; 3831da177e4SLinus Torvalds } 3841da177e4SLinus Torvalds if (!*paa) 3851da177e4SLinus Torvalds idp->layers = 0; 386cf481c20SNadia Derbey if (to_free) 387cf481c20SNadia Derbey free_layer(to_free); 388e15ae2ddSJesper Juhl } else 3891da177e4SLinus Torvalds idr_remove_warning(id); 3901da177e4SLinus Torvalds } 3911da177e4SLinus Torvalds 3921da177e4SLinus Torvalds /** 39356083ab1SRandy Dunlap * idr_remove - remove the given id and free its slot 39472fd4a35SRobert P. J. Day * @idp: idr handle 39572fd4a35SRobert P. J. Day * @id: unique key 3961da177e4SLinus Torvalds */ 3971da177e4SLinus Torvalds void idr_remove(struct idr *idp, int id) 3981da177e4SLinus Torvalds { 3991da177e4SLinus Torvalds struct idr_layer *p; 400cf481c20SNadia Derbey struct idr_layer *to_free; 4011da177e4SLinus Torvalds 4021da177e4SLinus Torvalds /* Mask off upper bits we don't use for the search. */ 4031da177e4SLinus Torvalds id &= MAX_ID_MASK; 4041da177e4SLinus Torvalds 4051da177e4SLinus Torvalds sub_remove(idp, (idp->layers - 1) * IDR_BITS, id); 406e15ae2ddSJesper Juhl if (idp->top && idp->top->count == 1 && (idp->layers > 1) && 407cf481c20SNadia Derbey idp->top->ary[0]) { 408cf481c20SNadia Derbey /* 409cf481c20SNadia Derbey * Single child at leftmost slot: we can shrink the tree. 410cf481c20SNadia Derbey * This level is not needed anymore since when layers are 411cf481c20SNadia Derbey * inserted, they are inserted at the top of the existing 412cf481c20SNadia Derbey * tree. 413cf481c20SNadia Derbey */ 414cf481c20SNadia Derbey to_free = idp->top; 4151da177e4SLinus Torvalds p = idp->top->ary[0]; 416cf481c20SNadia Derbey rcu_assign_pointer(idp->top, p); 4171da177e4SLinus Torvalds --idp->layers; 418cf481c20SNadia Derbey to_free->bitmap = to_free->count = 0; 419cf481c20SNadia Derbey free_layer(to_free); 4201da177e4SLinus Torvalds } 4211da177e4SLinus Torvalds while (idp->id_free_cnt >= IDR_FREE_MAX) { 4224ae53789SNadia Derbey p = get_from_free_list(idp); 423cf481c20SNadia Derbey /* 424cf481c20SNadia Derbey * Note: we don't call the rcu callback here, since the only 425cf481c20SNadia Derbey * layers that fall into the freelist are those that have been 426cf481c20SNadia Derbey * preallocated. 427cf481c20SNadia Derbey */ 4281da177e4SLinus Torvalds kmem_cache_free(idr_layer_cache, p); 4291da177e4SLinus Torvalds } 430af8e2a4cSNadia Derbey return; 4311da177e4SLinus Torvalds } 4321da177e4SLinus Torvalds EXPORT_SYMBOL(idr_remove); 4331da177e4SLinus Torvalds 4341da177e4SLinus Torvalds /** 43523936cc0SKristian Hoegsberg * idr_remove_all - remove all ids from the given idr tree 43623936cc0SKristian Hoegsberg * @idp: idr handle 43723936cc0SKristian Hoegsberg * 43823936cc0SKristian Hoegsberg * idr_destroy() only frees up unused, cached idp_layers, but this 43923936cc0SKristian Hoegsberg * function will remove all id mappings and leave all idp_layers 44023936cc0SKristian Hoegsberg * unused. 44123936cc0SKristian Hoegsberg * 44256083ab1SRandy Dunlap * A typical clean-up sequence for objects stored in an idr tree will 44323936cc0SKristian Hoegsberg * use idr_for_each() to free all objects, if necessay, then 44423936cc0SKristian Hoegsberg * idr_remove_all() to remove all ids, and idr_destroy() to free 44523936cc0SKristian Hoegsberg * up the cached idr_layers. 44623936cc0SKristian Hoegsberg */ 44723936cc0SKristian Hoegsberg void idr_remove_all(struct idr *idp) 44823936cc0SKristian Hoegsberg { 4496ace06dcSOleg Nesterov int n, id, max; 4502dcb22b3SImre Deak int bt_mask; 45123936cc0SKristian Hoegsberg struct idr_layer *p; 45223936cc0SKristian Hoegsberg struct idr_layer *pa[MAX_LEVEL]; 45323936cc0SKristian Hoegsberg struct idr_layer **paa = &pa[0]; 45423936cc0SKristian Hoegsberg 45523936cc0SKristian Hoegsberg n = idp->layers * IDR_BITS; 45623936cc0SKristian Hoegsberg p = idp->top; 4571b23336aSPaul E. McKenney rcu_assign_pointer(idp->top, NULL); 45823936cc0SKristian Hoegsberg max = 1 << n; 45923936cc0SKristian Hoegsberg 46023936cc0SKristian Hoegsberg id = 0; 4616ace06dcSOleg Nesterov while (id < max) { 46223936cc0SKristian Hoegsberg while (n > IDR_BITS && p) { 46323936cc0SKristian Hoegsberg n -= IDR_BITS; 46423936cc0SKristian Hoegsberg *paa++ = p; 46523936cc0SKristian Hoegsberg p = p->ary[(id >> n) & IDR_MASK]; 46623936cc0SKristian Hoegsberg } 46723936cc0SKristian Hoegsberg 4682dcb22b3SImre Deak bt_mask = id; 46923936cc0SKristian Hoegsberg id += 1 << n; 4702dcb22b3SImre Deak /* Get the highest bit that the above add changed from 0->1. */ 4712dcb22b3SImre Deak while (n < fls(id ^ bt_mask)) { 472cf481c20SNadia Derbey if (p) 473cf481c20SNadia Derbey free_layer(p); 47423936cc0SKristian Hoegsberg n += IDR_BITS; 47523936cc0SKristian Hoegsberg p = *--paa; 47623936cc0SKristian Hoegsberg } 47723936cc0SKristian Hoegsberg } 47823936cc0SKristian Hoegsberg idp->layers = 0; 47923936cc0SKristian Hoegsberg } 48023936cc0SKristian Hoegsberg EXPORT_SYMBOL(idr_remove_all); 48123936cc0SKristian Hoegsberg 48223936cc0SKristian Hoegsberg /** 4838d3b3591SAndrew Morton * idr_destroy - release all cached layers within an idr tree 484ea24ea85SNaohiro Aota * @idp: idr handle 4858d3b3591SAndrew Morton */ 4868d3b3591SAndrew Morton void idr_destroy(struct idr *idp) 4878d3b3591SAndrew Morton { 4888d3b3591SAndrew Morton while (idp->id_free_cnt) { 4894ae53789SNadia Derbey struct idr_layer *p = get_from_free_list(idp); 4908d3b3591SAndrew Morton kmem_cache_free(idr_layer_cache, p); 4918d3b3591SAndrew Morton } 4928d3b3591SAndrew Morton } 4938d3b3591SAndrew Morton EXPORT_SYMBOL(idr_destroy); 4948d3b3591SAndrew Morton 4958d3b3591SAndrew Morton /** 4961da177e4SLinus Torvalds * idr_find - return pointer for given id 4971da177e4SLinus Torvalds * @idp: idr handle 4981da177e4SLinus Torvalds * @id: lookup key 4991da177e4SLinus Torvalds * 5001da177e4SLinus Torvalds * Return the pointer given the id it has been registered with. A %NULL 5011da177e4SLinus Torvalds * return indicates that @id is not valid or you passed %NULL in 5021da177e4SLinus Torvalds * idr_get_new(). 5031da177e4SLinus Torvalds * 504f9c46d6eSNadia Derbey * This function can be called under rcu_read_lock(), given that the leaf 505f9c46d6eSNadia Derbey * pointers lifetimes are correctly managed. 5061da177e4SLinus Torvalds */ 5071da177e4SLinus Torvalds void *idr_find(struct idr *idp, int id) 5081da177e4SLinus Torvalds { 5091da177e4SLinus Torvalds int n; 5101da177e4SLinus Torvalds struct idr_layer *p; 5111da177e4SLinus Torvalds 51296be753aSPaul E. McKenney p = rcu_dereference_raw(idp->top); 5136ff2d39bSManfred Spraul if (!p) 5146ff2d39bSManfred Spraul return NULL; 5156ff2d39bSManfred Spraul n = (p->layer+1) * IDR_BITS; 5161da177e4SLinus Torvalds 5171da177e4SLinus Torvalds /* Mask off upper bits we don't use for the search. */ 5181da177e4SLinus Torvalds id &= MAX_ID_MASK; 5191da177e4SLinus Torvalds 5201da177e4SLinus Torvalds if (id >= (1 << n)) 5211da177e4SLinus Torvalds return NULL; 5226ff2d39bSManfred Spraul BUG_ON(n == 0); 5231da177e4SLinus Torvalds 5241da177e4SLinus Torvalds while (n > 0 && p) { 5251da177e4SLinus Torvalds n -= IDR_BITS; 5266ff2d39bSManfred Spraul BUG_ON(n != p->layer*IDR_BITS); 52796be753aSPaul E. McKenney p = rcu_dereference_raw(p->ary[(id >> n) & IDR_MASK]); 5281da177e4SLinus Torvalds } 5291da177e4SLinus Torvalds return((void *)p); 5301da177e4SLinus Torvalds } 5311da177e4SLinus Torvalds EXPORT_SYMBOL(idr_find); 5321da177e4SLinus Torvalds 5335806f07cSJeff Mahoney /** 53496d7fa42SKristian Hoegsberg * idr_for_each - iterate through all stored pointers 53596d7fa42SKristian Hoegsberg * @idp: idr handle 53696d7fa42SKristian Hoegsberg * @fn: function to be called for each pointer 53796d7fa42SKristian Hoegsberg * @data: data passed back to callback function 53896d7fa42SKristian Hoegsberg * 53996d7fa42SKristian Hoegsberg * Iterate over the pointers registered with the given idr. The 54096d7fa42SKristian Hoegsberg * callback function will be called for each pointer currently 54196d7fa42SKristian Hoegsberg * registered, passing the id, the pointer and the data pointer passed 54296d7fa42SKristian Hoegsberg * to this function. It is not safe to modify the idr tree while in 54396d7fa42SKristian Hoegsberg * the callback, so functions such as idr_get_new and idr_remove are 54496d7fa42SKristian Hoegsberg * not allowed. 54596d7fa42SKristian Hoegsberg * 54696d7fa42SKristian Hoegsberg * We check the return of @fn each time. If it returns anything other 54756083ab1SRandy Dunlap * than %0, we break out and return that value. 54896d7fa42SKristian Hoegsberg * 54996d7fa42SKristian Hoegsberg * The caller must serialize idr_for_each() vs idr_get_new() and idr_remove(). 55096d7fa42SKristian Hoegsberg */ 55196d7fa42SKristian Hoegsberg int idr_for_each(struct idr *idp, 55296d7fa42SKristian Hoegsberg int (*fn)(int id, void *p, void *data), void *data) 55396d7fa42SKristian Hoegsberg { 55496d7fa42SKristian Hoegsberg int n, id, max, error = 0; 55596d7fa42SKristian Hoegsberg struct idr_layer *p; 55696d7fa42SKristian Hoegsberg struct idr_layer *pa[MAX_LEVEL]; 55796d7fa42SKristian Hoegsberg struct idr_layer **paa = &pa[0]; 55896d7fa42SKristian Hoegsberg 55996d7fa42SKristian Hoegsberg n = idp->layers * IDR_BITS; 56096be753aSPaul E. McKenney p = rcu_dereference_raw(idp->top); 56196d7fa42SKristian Hoegsberg max = 1 << n; 56296d7fa42SKristian Hoegsberg 56396d7fa42SKristian Hoegsberg id = 0; 56496d7fa42SKristian Hoegsberg while (id < max) { 56596d7fa42SKristian Hoegsberg while (n > 0 && p) { 56696d7fa42SKristian Hoegsberg n -= IDR_BITS; 56796d7fa42SKristian Hoegsberg *paa++ = p; 56896be753aSPaul E. McKenney p = rcu_dereference_raw(p->ary[(id >> n) & IDR_MASK]); 56996d7fa42SKristian Hoegsberg } 57096d7fa42SKristian Hoegsberg 57196d7fa42SKristian Hoegsberg if (p) { 57296d7fa42SKristian Hoegsberg error = fn(id, (void *)p, data); 57396d7fa42SKristian Hoegsberg if (error) 57496d7fa42SKristian Hoegsberg break; 57596d7fa42SKristian Hoegsberg } 57696d7fa42SKristian Hoegsberg 57796d7fa42SKristian Hoegsberg id += 1 << n; 57896d7fa42SKristian Hoegsberg while (n < fls(id)) { 57996d7fa42SKristian Hoegsberg n += IDR_BITS; 58096d7fa42SKristian Hoegsberg p = *--paa; 58196d7fa42SKristian Hoegsberg } 58296d7fa42SKristian Hoegsberg } 58396d7fa42SKristian Hoegsberg 58496d7fa42SKristian Hoegsberg return error; 58596d7fa42SKristian Hoegsberg } 58696d7fa42SKristian Hoegsberg EXPORT_SYMBOL(idr_for_each); 58796d7fa42SKristian Hoegsberg 58896d7fa42SKristian Hoegsberg /** 58938460b48SKAMEZAWA Hiroyuki * idr_get_next - lookup next object of id to given id. 59038460b48SKAMEZAWA Hiroyuki * @idp: idr handle 591ea24ea85SNaohiro Aota * @nextidp: pointer to lookup key 59238460b48SKAMEZAWA Hiroyuki * 59338460b48SKAMEZAWA Hiroyuki * Returns pointer to registered object with id, which is next number to 5941458ce16SNaohiro Aota * given id. After being looked up, *@nextidp will be updated for the next 5951458ce16SNaohiro Aota * iteration. 59638460b48SKAMEZAWA Hiroyuki */ 59738460b48SKAMEZAWA Hiroyuki 59838460b48SKAMEZAWA Hiroyuki void *idr_get_next(struct idr *idp, int *nextidp) 59938460b48SKAMEZAWA Hiroyuki { 60038460b48SKAMEZAWA Hiroyuki struct idr_layer *p, *pa[MAX_LEVEL]; 60138460b48SKAMEZAWA Hiroyuki struct idr_layer **paa = &pa[0]; 60238460b48SKAMEZAWA Hiroyuki int id = *nextidp; 60338460b48SKAMEZAWA Hiroyuki int n, max; 60438460b48SKAMEZAWA Hiroyuki 60538460b48SKAMEZAWA Hiroyuki /* find first ent */ 60638460b48SKAMEZAWA Hiroyuki n = idp->layers * IDR_BITS; 60738460b48SKAMEZAWA Hiroyuki max = 1 << n; 60894bfa3b6SPaul E. McKenney p = rcu_dereference_raw(idp->top); 60938460b48SKAMEZAWA Hiroyuki if (!p) 61038460b48SKAMEZAWA Hiroyuki return NULL; 61138460b48SKAMEZAWA Hiroyuki 61238460b48SKAMEZAWA Hiroyuki while (id < max) { 61338460b48SKAMEZAWA Hiroyuki while (n > 0 && p) { 61438460b48SKAMEZAWA Hiroyuki n -= IDR_BITS; 61538460b48SKAMEZAWA Hiroyuki *paa++ = p; 61694bfa3b6SPaul E. McKenney p = rcu_dereference_raw(p->ary[(id >> n) & IDR_MASK]); 61738460b48SKAMEZAWA Hiroyuki } 61838460b48SKAMEZAWA Hiroyuki 61938460b48SKAMEZAWA Hiroyuki if (p) { 62038460b48SKAMEZAWA Hiroyuki *nextidp = id; 62138460b48SKAMEZAWA Hiroyuki return p; 62238460b48SKAMEZAWA Hiroyuki } 62338460b48SKAMEZAWA Hiroyuki 62438460b48SKAMEZAWA Hiroyuki id += 1 << n; 62538460b48SKAMEZAWA Hiroyuki while (n < fls(id)) { 62638460b48SKAMEZAWA Hiroyuki n += IDR_BITS; 62738460b48SKAMEZAWA Hiroyuki p = *--paa; 62838460b48SKAMEZAWA Hiroyuki } 62938460b48SKAMEZAWA Hiroyuki } 63038460b48SKAMEZAWA Hiroyuki return NULL; 63138460b48SKAMEZAWA Hiroyuki } 6324d1ee80fSBen Hutchings EXPORT_SYMBOL(idr_get_next); 63338460b48SKAMEZAWA Hiroyuki 63438460b48SKAMEZAWA Hiroyuki 63538460b48SKAMEZAWA Hiroyuki /** 6365806f07cSJeff Mahoney * idr_replace - replace pointer for given id 6375806f07cSJeff Mahoney * @idp: idr handle 6385806f07cSJeff Mahoney * @ptr: pointer you want associated with the id 6395806f07cSJeff Mahoney * @id: lookup key 6405806f07cSJeff Mahoney * 6415806f07cSJeff Mahoney * Replace the pointer registered with an id and return the old value. 64256083ab1SRandy Dunlap * A %-ENOENT return indicates that @id was not found. 64356083ab1SRandy Dunlap * A %-EINVAL return indicates that @id was not within valid constraints. 6445806f07cSJeff Mahoney * 645cf481c20SNadia Derbey * The caller must serialize with writers. 6465806f07cSJeff Mahoney */ 6475806f07cSJeff Mahoney void *idr_replace(struct idr *idp, void *ptr, int id) 6485806f07cSJeff Mahoney { 6495806f07cSJeff Mahoney int n; 6505806f07cSJeff Mahoney struct idr_layer *p, *old_p; 6515806f07cSJeff Mahoney 6525806f07cSJeff Mahoney p = idp->top; 6536ff2d39bSManfred Spraul if (!p) 6546ff2d39bSManfred Spraul return ERR_PTR(-EINVAL); 6556ff2d39bSManfred Spraul 6566ff2d39bSManfred Spraul n = (p->layer+1) * IDR_BITS; 6575806f07cSJeff Mahoney 6585806f07cSJeff Mahoney id &= MAX_ID_MASK; 6595806f07cSJeff Mahoney 6605806f07cSJeff Mahoney if (id >= (1 << n)) 6615806f07cSJeff Mahoney return ERR_PTR(-EINVAL); 6625806f07cSJeff Mahoney 6635806f07cSJeff Mahoney n -= IDR_BITS; 6645806f07cSJeff Mahoney while ((n > 0) && p) { 6655806f07cSJeff Mahoney p = p->ary[(id >> n) & IDR_MASK]; 6665806f07cSJeff Mahoney n -= IDR_BITS; 6675806f07cSJeff Mahoney } 6685806f07cSJeff Mahoney 6695806f07cSJeff Mahoney n = id & IDR_MASK; 6705806f07cSJeff Mahoney if (unlikely(p == NULL || !test_bit(n, &p->bitmap))) 6715806f07cSJeff Mahoney return ERR_PTR(-ENOENT); 6725806f07cSJeff Mahoney 6735806f07cSJeff Mahoney old_p = p->ary[n]; 674cf481c20SNadia Derbey rcu_assign_pointer(p->ary[n], ptr); 6755806f07cSJeff Mahoney 6765806f07cSJeff Mahoney return old_p; 6775806f07cSJeff Mahoney } 6785806f07cSJeff Mahoney EXPORT_SYMBOL(idr_replace); 6795806f07cSJeff Mahoney 680199f0ca5SAkinobu Mita void __init idr_init_cache(void) 6811da177e4SLinus Torvalds { 6821da177e4SLinus Torvalds idr_layer_cache = kmem_cache_create("idr_layer_cache", 6835b019e99SAndrew Morton sizeof(struct idr_layer), 0, SLAB_PANIC, NULL); 6841da177e4SLinus Torvalds } 6851da177e4SLinus Torvalds 6861da177e4SLinus Torvalds /** 6871da177e4SLinus Torvalds * idr_init - initialize idr handle 6881da177e4SLinus Torvalds * @idp: idr handle 6891da177e4SLinus Torvalds * 6901da177e4SLinus Torvalds * This function is use to set up the handle (@idp) that you will pass 6911da177e4SLinus Torvalds * to the rest of the functions. 6921da177e4SLinus Torvalds */ 6931da177e4SLinus Torvalds void idr_init(struct idr *idp) 6941da177e4SLinus Torvalds { 6951da177e4SLinus Torvalds memset(idp, 0, sizeof(struct idr)); 6961da177e4SLinus Torvalds spin_lock_init(&idp->lock); 6971da177e4SLinus Torvalds } 6981da177e4SLinus Torvalds EXPORT_SYMBOL(idr_init); 69972dba584STejun Heo 70072dba584STejun Heo 70156083ab1SRandy Dunlap /** 70256083ab1SRandy Dunlap * DOC: IDA description 70372dba584STejun Heo * IDA - IDR based ID allocator 70472dba584STejun Heo * 70556083ab1SRandy Dunlap * This is id allocator without id -> pointer translation. Memory 70672dba584STejun Heo * usage is much lower than full blown idr because each id only 70772dba584STejun Heo * occupies a bit. ida uses a custom leaf node which contains 70872dba584STejun Heo * IDA_BITMAP_BITS slots. 70972dba584STejun Heo * 71072dba584STejun Heo * 2007-04-25 written by Tejun Heo <htejun@gmail.com> 71172dba584STejun Heo */ 71272dba584STejun Heo 71372dba584STejun Heo static void free_bitmap(struct ida *ida, struct ida_bitmap *bitmap) 71472dba584STejun Heo { 71572dba584STejun Heo unsigned long flags; 71672dba584STejun Heo 71772dba584STejun Heo if (!ida->free_bitmap) { 71872dba584STejun Heo spin_lock_irqsave(&ida->idr.lock, flags); 71972dba584STejun Heo if (!ida->free_bitmap) { 72072dba584STejun Heo ida->free_bitmap = bitmap; 72172dba584STejun Heo bitmap = NULL; 72272dba584STejun Heo } 72372dba584STejun Heo spin_unlock_irqrestore(&ida->idr.lock, flags); 72472dba584STejun Heo } 72572dba584STejun Heo 72672dba584STejun Heo kfree(bitmap); 72772dba584STejun Heo } 72872dba584STejun Heo 72972dba584STejun Heo /** 73072dba584STejun Heo * ida_pre_get - reserve resources for ida allocation 73172dba584STejun Heo * @ida: ida handle 73272dba584STejun Heo * @gfp_mask: memory allocation flag 73372dba584STejun Heo * 73472dba584STejun Heo * This function should be called prior to locking and calling the 73572dba584STejun Heo * following function. It preallocates enough memory to satisfy the 73672dba584STejun Heo * worst possible allocation. 73772dba584STejun Heo * 73856083ab1SRandy Dunlap * If the system is REALLY out of memory this function returns %0, 73956083ab1SRandy Dunlap * otherwise %1. 74072dba584STejun Heo */ 74172dba584STejun Heo int ida_pre_get(struct ida *ida, gfp_t gfp_mask) 74272dba584STejun Heo { 74372dba584STejun Heo /* allocate idr_layers */ 74472dba584STejun Heo if (!idr_pre_get(&ida->idr, gfp_mask)) 74572dba584STejun Heo return 0; 74672dba584STejun Heo 74772dba584STejun Heo /* allocate free_bitmap */ 74872dba584STejun Heo if (!ida->free_bitmap) { 74972dba584STejun Heo struct ida_bitmap *bitmap; 75072dba584STejun Heo 75172dba584STejun Heo bitmap = kmalloc(sizeof(struct ida_bitmap), gfp_mask); 75272dba584STejun Heo if (!bitmap) 75372dba584STejun Heo return 0; 75472dba584STejun Heo 75572dba584STejun Heo free_bitmap(ida, bitmap); 75672dba584STejun Heo } 75772dba584STejun Heo 75872dba584STejun Heo return 1; 75972dba584STejun Heo } 76072dba584STejun Heo EXPORT_SYMBOL(ida_pre_get); 76172dba584STejun Heo 76272dba584STejun Heo /** 76372dba584STejun Heo * ida_get_new_above - allocate new ID above or equal to a start id 76472dba584STejun Heo * @ida: ida handle 765ea24ea85SNaohiro Aota * @starting_id: id to start search at 76672dba584STejun Heo * @p_id: pointer to the allocated handle 76772dba584STejun Heo * 76872dba584STejun Heo * Allocate new ID above or equal to @ida. It should be called with 76972dba584STejun Heo * any required locks. 77072dba584STejun Heo * 77156083ab1SRandy Dunlap * If memory is required, it will return %-EAGAIN, you should unlock 77272dba584STejun Heo * and go back to the ida_pre_get() call. If the ida is full, it will 77356083ab1SRandy Dunlap * return %-ENOSPC. 77472dba584STejun Heo * 77556083ab1SRandy Dunlap * @p_id returns a value in the range @starting_id ... %0x7fffffff. 77672dba584STejun Heo */ 77772dba584STejun Heo int ida_get_new_above(struct ida *ida, int starting_id, int *p_id) 77872dba584STejun Heo { 77972dba584STejun Heo struct idr_layer *pa[MAX_LEVEL]; 78072dba584STejun Heo struct ida_bitmap *bitmap; 78172dba584STejun Heo unsigned long flags; 78272dba584STejun Heo int idr_id = starting_id / IDA_BITMAP_BITS; 78372dba584STejun Heo int offset = starting_id % IDA_BITMAP_BITS; 78472dba584STejun Heo int t, id; 78572dba584STejun Heo 78672dba584STejun Heo restart: 78772dba584STejun Heo /* get vacant slot */ 78872dba584STejun Heo t = idr_get_empty_slot(&ida->idr, idr_id, pa); 789944ca05cSNadia Derbey if (t < 0) 790944ca05cSNadia Derbey return _idr_rc_to_errno(t); 79172dba584STejun Heo 79272dba584STejun Heo if (t * IDA_BITMAP_BITS >= MAX_ID_BIT) 79372dba584STejun Heo return -ENOSPC; 79472dba584STejun Heo 79572dba584STejun Heo if (t != idr_id) 79672dba584STejun Heo offset = 0; 79772dba584STejun Heo idr_id = t; 79872dba584STejun Heo 79972dba584STejun Heo /* if bitmap isn't there, create a new one */ 80072dba584STejun Heo bitmap = (void *)pa[0]->ary[idr_id & IDR_MASK]; 80172dba584STejun Heo if (!bitmap) { 80272dba584STejun Heo spin_lock_irqsave(&ida->idr.lock, flags); 80372dba584STejun Heo bitmap = ida->free_bitmap; 80472dba584STejun Heo ida->free_bitmap = NULL; 80572dba584STejun Heo spin_unlock_irqrestore(&ida->idr.lock, flags); 80672dba584STejun Heo 80772dba584STejun Heo if (!bitmap) 80872dba584STejun Heo return -EAGAIN; 80972dba584STejun Heo 81072dba584STejun Heo memset(bitmap, 0, sizeof(struct ida_bitmap)); 8113219b3b7SNadia Derbey rcu_assign_pointer(pa[0]->ary[idr_id & IDR_MASK], 8123219b3b7SNadia Derbey (void *)bitmap); 81372dba584STejun Heo pa[0]->count++; 81472dba584STejun Heo } 81572dba584STejun Heo 81672dba584STejun Heo /* lookup for empty slot */ 81772dba584STejun Heo t = find_next_zero_bit(bitmap->bitmap, IDA_BITMAP_BITS, offset); 81872dba584STejun Heo if (t == IDA_BITMAP_BITS) { 81972dba584STejun Heo /* no empty slot after offset, continue to the next chunk */ 82072dba584STejun Heo idr_id++; 82172dba584STejun Heo offset = 0; 82272dba584STejun Heo goto restart; 82372dba584STejun Heo } 82472dba584STejun Heo 82572dba584STejun Heo id = idr_id * IDA_BITMAP_BITS + t; 82672dba584STejun Heo if (id >= MAX_ID_BIT) 82772dba584STejun Heo return -ENOSPC; 82872dba584STejun Heo 82972dba584STejun Heo __set_bit(t, bitmap->bitmap); 83072dba584STejun Heo if (++bitmap->nr_busy == IDA_BITMAP_BITS) 83172dba584STejun Heo idr_mark_full(pa, idr_id); 83272dba584STejun Heo 83372dba584STejun Heo *p_id = id; 83472dba584STejun Heo 83572dba584STejun Heo /* Each leaf node can handle nearly a thousand slots and the 83672dba584STejun Heo * whole idea of ida is to have small memory foot print. 83772dba584STejun Heo * Throw away extra resources one by one after each successful 83872dba584STejun Heo * allocation. 83972dba584STejun Heo */ 84072dba584STejun Heo if (ida->idr.id_free_cnt || ida->free_bitmap) { 8414ae53789SNadia Derbey struct idr_layer *p = get_from_free_list(&ida->idr); 84272dba584STejun Heo if (p) 84372dba584STejun Heo kmem_cache_free(idr_layer_cache, p); 84472dba584STejun Heo } 84572dba584STejun Heo 84672dba584STejun Heo return 0; 84772dba584STejun Heo } 84872dba584STejun Heo EXPORT_SYMBOL(ida_get_new_above); 84972dba584STejun Heo 85072dba584STejun Heo /** 85172dba584STejun Heo * ida_get_new - allocate new ID 85272dba584STejun Heo * @ida: idr handle 85372dba584STejun Heo * @p_id: pointer to the allocated handle 85472dba584STejun Heo * 85572dba584STejun Heo * Allocate new ID. It should be called with any required locks. 85672dba584STejun Heo * 85756083ab1SRandy Dunlap * If memory is required, it will return %-EAGAIN, you should unlock 85872dba584STejun Heo * and go back to the idr_pre_get() call. If the idr is full, it will 85956083ab1SRandy Dunlap * return %-ENOSPC. 86072dba584STejun Heo * 86156083ab1SRandy Dunlap * @id returns a value in the range %0 ... %0x7fffffff. 86272dba584STejun Heo */ 86372dba584STejun Heo int ida_get_new(struct ida *ida, int *p_id) 86472dba584STejun Heo { 86572dba584STejun Heo return ida_get_new_above(ida, 0, p_id); 86672dba584STejun Heo } 86772dba584STejun Heo EXPORT_SYMBOL(ida_get_new); 86872dba584STejun Heo 86972dba584STejun Heo /** 87072dba584STejun Heo * ida_remove - remove the given ID 87172dba584STejun Heo * @ida: ida handle 87272dba584STejun Heo * @id: ID to free 87372dba584STejun Heo */ 87472dba584STejun Heo void ida_remove(struct ida *ida, int id) 87572dba584STejun Heo { 87672dba584STejun Heo struct idr_layer *p = ida->idr.top; 87772dba584STejun Heo int shift = (ida->idr.layers - 1) * IDR_BITS; 87872dba584STejun Heo int idr_id = id / IDA_BITMAP_BITS; 87972dba584STejun Heo int offset = id % IDA_BITMAP_BITS; 88072dba584STejun Heo int n; 88172dba584STejun Heo struct ida_bitmap *bitmap; 88272dba584STejun Heo 88372dba584STejun Heo /* clear full bits while looking up the leaf idr_layer */ 88472dba584STejun Heo while ((shift > 0) && p) { 88572dba584STejun Heo n = (idr_id >> shift) & IDR_MASK; 88672dba584STejun Heo __clear_bit(n, &p->bitmap); 88772dba584STejun Heo p = p->ary[n]; 88872dba584STejun Heo shift -= IDR_BITS; 88972dba584STejun Heo } 89072dba584STejun Heo 89172dba584STejun Heo if (p == NULL) 89272dba584STejun Heo goto err; 89372dba584STejun Heo 89472dba584STejun Heo n = idr_id & IDR_MASK; 89572dba584STejun Heo __clear_bit(n, &p->bitmap); 89672dba584STejun Heo 89772dba584STejun Heo bitmap = (void *)p->ary[n]; 89872dba584STejun Heo if (!test_bit(offset, bitmap->bitmap)) 89972dba584STejun Heo goto err; 90072dba584STejun Heo 90172dba584STejun Heo /* update bitmap and remove it if empty */ 90272dba584STejun Heo __clear_bit(offset, bitmap->bitmap); 90372dba584STejun Heo if (--bitmap->nr_busy == 0) { 90472dba584STejun Heo __set_bit(n, &p->bitmap); /* to please idr_remove() */ 90572dba584STejun Heo idr_remove(&ida->idr, idr_id); 90672dba584STejun Heo free_bitmap(ida, bitmap); 90772dba584STejun Heo } 90872dba584STejun Heo 90972dba584STejun Heo return; 91072dba584STejun Heo 91172dba584STejun Heo err: 91272dba584STejun Heo printk(KERN_WARNING 91372dba584STejun Heo "ida_remove called for id=%d which is not allocated.\n", id); 91472dba584STejun Heo } 91572dba584STejun Heo EXPORT_SYMBOL(ida_remove); 91672dba584STejun Heo 91772dba584STejun Heo /** 91872dba584STejun Heo * ida_destroy - release all cached layers within an ida tree 919ea24ea85SNaohiro Aota * @ida: ida handle 92072dba584STejun Heo */ 92172dba584STejun Heo void ida_destroy(struct ida *ida) 92272dba584STejun Heo { 92372dba584STejun Heo idr_destroy(&ida->idr); 92472dba584STejun Heo kfree(ida->free_bitmap); 92572dba584STejun Heo } 92672dba584STejun Heo EXPORT_SYMBOL(ida_destroy); 92772dba584STejun Heo 92872dba584STejun Heo /** 92972dba584STejun Heo * ida_init - initialize ida handle 93072dba584STejun Heo * @ida: ida handle 93172dba584STejun Heo * 93272dba584STejun Heo * This function is use to set up the handle (@ida) that you will pass 93372dba584STejun Heo * to the rest of the functions. 93472dba584STejun Heo */ 93572dba584STejun Heo void ida_init(struct ida *ida) 93672dba584STejun Heo { 93772dba584STejun Heo memset(ida, 0, sizeof(struct ida)); 93872dba584STejun Heo idr_init(&ida->idr); 93972dba584STejun Heo 94072dba584STejun Heo } 94172dba584STejun Heo EXPORT_SYMBOL(ida_init); 942