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 23125c4c70SFengguang Wu * the memory is returned (we keep MAX_IDR_FREE) 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> 328bc3bcc9SPaul Gortmaker #include <linux/export.h> 331da177e4SLinus Torvalds #endif 345806f07cSJeff Mahoney #include <linux/err.h> 351da177e4SLinus Torvalds #include <linux/string.h> 361da177e4SLinus Torvalds #include <linux/idr.h> 3788eca020SRusty Russell #include <linux/spinlock.h> 381da177e4SLinus Torvalds 39e18b890bSChristoph Lameter static struct kmem_cache *idr_layer_cache; 4088eca020SRusty Russell static DEFINE_SPINLOCK(simple_ida_lock); 411da177e4SLinus Torvalds 424ae53789SNadia Derbey static struct idr_layer *get_from_free_list(struct idr *idp) 431da177e4SLinus Torvalds { 441da177e4SLinus Torvalds struct idr_layer *p; 45c259cc28SRoland Dreier unsigned long flags; 461da177e4SLinus Torvalds 47c259cc28SRoland Dreier spin_lock_irqsave(&idp->lock, flags); 481da177e4SLinus Torvalds if ((p = idp->id_free)) { 491da177e4SLinus Torvalds idp->id_free = p->ary[0]; 501da177e4SLinus Torvalds idp->id_free_cnt--; 511da177e4SLinus Torvalds p->ary[0] = NULL; 521da177e4SLinus Torvalds } 53c259cc28SRoland Dreier spin_unlock_irqrestore(&idp->lock, flags); 541da177e4SLinus Torvalds return(p); 551da177e4SLinus Torvalds } 561da177e4SLinus Torvalds 57cf481c20SNadia Derbey static void idr_layer_rcu_free(struct rcu_head *head) 58cf481c20SNadia Derbey { 59cf481c20SNadia Derbey struct idr_layer *layer; 60cf481c20SNadia Derbey 61cf481c20SNadia Derbey layer = container_of(head, struct idr_layer, rcu_head); 62cf481c20SNadia Derbey kmem_cache_free(idr_layer_cache, layer); 63cf481c20SNadia Derbey } 64cf481c20SNadia Derbey 65cf481c20SNadia Derbey static inline void free_layer(struct idr_layer *p) 66cf481c20SNadia Derbey { 67cf481c20SNadia Derbey call_rcu(&p->rcu_head, idr_layer_rcu_free); 68cf481c20SNadia Derbey } 69cf481c20SNadia Derbey 701eec0056SSonny Rao /* only called when idp->lock is held */ 714ae53789SNadia Derbey static void __move_to_free_list(struct idr *idp, struct idr_layer *p) 721eec0056SSonny Rao { 731eec0056SSonny Rao p->ary[0] = idp->id_free; 741eec0056SSonny Rao idp->id_free = p; 751eec0056SSonny Rao idp->id_free_cnt++; 761eec0056SSonny Rao } 771eec0056SSonny Rao 784ae53789SNadia Derbey static void move_to_free_list(struct idr *idp, struct idr_layer *p) 791da177e4SLinus Torvalds { 80c259cc28SRoland Dreier unsigned long flags; 81c259cc28SRoland Dreier 821da177e4SLinus Torvalds /* 831da177e4SLinus Torvalds * Depends on the return element being zeroed. 841da177e4SLinus Torvalds */ 85c259cc28SRoland Dreier spin_lock_irqsave(&idp->lock, flags); 864ae53789SNadia Derbey __move_to_free_list(idp, p); 87c259cc28SRoland Dreier spin_unlock_irqrestore(&idp->lock, flags); 881da177e4SLinus Torvalds } 891da177e4SLinus Torvalds 90e33ac8bdSTejun Heo static void idr_mark_full(struct idr_layer **pa, int id) 91e33ac8bdSTejun Heo { 92e33ac8bdSTejun Heo struct idr_layer *p = pa[0]; 93e33ac8bdSTejun Heo int l = 0; 94e33ac8bdSTejun Heo 95e33ac8bdSTejun Heo __set_bit(id & IDR_MASK, &p->bitmap); 96e33ac8bdSTejun Heo /* 97e33ac8bdSTejun Heo * If this layer is full mark the bit in the layer above to 98e33ac8bdSTejun Heo * show that this part of the radix tree is full. This may 99e33ac8bdSTejun Heo * complete the layer above and require walking up the radix 100e33ac8bdSTejun Heo * tree. 101e33ac8bdSTejun Heo */ 102e33ac8bdSTejun Heo while (p->bitmap == IDR_FULL) { 103e33ac8bdSTejun Heo if (!(p = pa[++l])) 104e33ac8bdSTejun Heo break; 105e33ac8bdSTejun Heo id = id >> IDR_BITS; 106e33ac8bdSTejun Heo __set_bit((id & IDR_MASK), &p->bitmap); 107e33ac8bdSTejun Heo } 108e33ac8bdSTejun Heo } 109e33ac8bdSTejun Heo 1101da177e4SLinus Torvalds /** 11156083ab1SRandy Dunlap * idr_pre_get - reserve resources for idr allocation 1121da177e4SLinus Torvalds * @idp: idr handle 1131da177e4SLinus Torvalds * @gfp_mask: memory allocation flags 1141da177e4SLinus Torvalds * 115066a9be6SNaohiro Aota * This function should be called prior to calling the idr_get_new* functions. 116066a9be6SNaohiro Aota * It preallocates enough memory to satisfy the worst possible allocation. The 117066a9be6SNaohiro Aota * caller should pass in GFP_KERNEL if possible. This of course requires that 118066a9be6SNaohiro Aota * no spinning locks be held. 1191da177e4SLinus Torvalds * 12056083ab1SRandy Dunlap * If the system is REALLY out of memory this function returns %0, 12156083ab1SRandy Dunlap * otherwise %1. 1221da177e4SLinus Torvalds */ 123fd4f2df2SAl Viro int idr_pre_get(struct idr *idp, gfp_t gfp_mask) 1241da177e4SLinus Torvalds { 125125c4c70SFengguang Wu while (idp->id_free_cnt < MAX_IDR_FREE) { 1261da177e4SLinus Torvalds struct idr_layer *new; 1275b019e99SAndrew Morton new = kmem_cache_zalloc(idr_layer_cache, gfp_mask); 1281da177e4SLinus Torvalds if (new == NULL) 1291da177e4SLinus Torvalds return (0); 1304ae53789SNadia Derbey move_to_free_list(idp, new); 1311da177e4SLinus Torvalds } 1321da177e4SLinus Torvalds return 1; 1331da177e4SLinus Torvalds } 1341da177e4SLinus Torvalds EXPORT_SYMBOL(idr_pre_get); 1351da177e4SLinus Torvalds 13612d1b439STejun Heo /** 13712d1b439STejun Heo * sub_alloc - try to allocate an id without growing the tree depth 13812d1b439STejun Heo * @idp: idr handle 13912d1b439STejun Heo * @starting_id: id to start search at 14012d1b439STejun Heo * @id: pointer to the allocated handle 14112d1b439STejun Heo * @pa: idr_layer[MAX_IDR_LEVEL] used as backtrack buffer 14212d1b439STejun Heo * 14312d1b439STejun Heo * Allocate an id in range [@starting_id, INT_MAX] from @idp without 14412d1b439STejun Heo * growing its depth. Returns 14512d1b439STejun Heo * 14612d1b439STejun Heo * the allocated id >= 0 if successful, 14712d1b439STejun Heo * -EAGAIN if the tree needs to grow for allocation to succeed, 14812d1b439STejun Heo * -ENOSPC if the id space is exhausted, 14912d1b439STejun Heo * -ENOMEM if more idr_layers need to be allocated. 15012d1b439STejun Heo */ 151e33ac8bdSTejun Heo static int sub_alloc(struct idr *idp, int *starting_id, struct idr_layer **pa) 1521da177e4SLinus Torvalds { 1531da177e4SLinus Torvalds int n, m, sh; 1541da177e4SLinus Torvalds struct idr_layer *p, *new; 1557aae6dd8STejun Heo int l, id, oid; 1565ba25331SAl Viro unsigned long bm; 1571da177e4SLinus Torvalds 1581da177e4SLinus Torvalds id = *starting_id; 1597aae6dd8STejun Heo restart: 1601da177e4SLinus Torvalds p = idp->top; 1611da177e4SLinus Torvalds l = idp->layers; 1621da177e4SLinus Torvalds pa[l--] = NULL; 1631da177e4SLinus Torvalds while (1) { 1641da177e4SLinus Torvalds /* 1651da177e4SLinus Torvalds * We run around this while until we reach the leaf node... 1661da177e4SLinus Torvalds */ 1671da177e4SLinus Torvalds n = (id >> (IDR_BITS*l)) & IDR_MASK; 1681da177e4SLinus Torvalds bm = ~p->bitmap; 1691da177e4SLinus Torvalds m = find_next_bit(&bm, IDR_SIZE, n); 1701da177e4SLinus Torvalds if (m == IDR_SIZE) { 1711da177e4SLinus Torvalds /* no space available go back to previous layer. */ 1721da177e4SLinus Torvalds l++; 1737aae6dd8STejun Heo oid = id; 1741da177e4SLinus Torvalds id = (id | ((1 << (IDR_BITS * l)) - 1)) + 1; 1757aae6dd8STejun Heo 1767aae6dd8STejun Heo /* if already at the top layer, we need to grow */ 177d2e7276bSTejun Heo if (id >= 1 << (idp->layers * IDR_BITS)) { 1781da177e4SLinus Torvalds *starting_id = id; 17912d1b439STejun Heo return -EAGAIN; 1801da177e4SLinus Torvalds } 181d2e7276bSTejun Heo p = pa[l]; 182d2e7276bSTejun Heo BUG_ON(!p); 1837aae6dd8STejun Heo 1847aae6dd8STejun Heo /* If we need to go up one layer, continue the 1857aae6dd8STejun Heo * loop; otherwise, restart from the top. 1867aae6dd8STejun Heo */ 1877aae6dd8STejun Heo sh = IDR_BITS * (l + 1); 1887aae6dd8STejun Heo if (oid >> sh == id >> sh) 1891da177e4SLinus Torvalds continue; 1907aae6dd8STejun Heo else 1917aae6dd8STejun Heo goto restart; 1921da177e4SLinus Torvalds } 1931da177e4SLinus Torvalds if (m != n) { 1941da177e4SLinus Torvalds sh = IDR_BITS*l; 1951da177e4SLinus Torvalds id = ((id >> sh) ^ n ^ m) << sh; 1961da177e4SLinus Torvalds } 197125c4c70SFengguang Wu if ((id >= MAX_IDR_BIT) || (id < 0)) 19812d1b439STejun Heo return -ENOSPC; 1991da177e4SLinus Torvalds if (l == 0) 2001da177e4SLinus Torvalds break; 2011da177e4SLinus Torvalds /* 2021da177e4SLinus Torvalds * Create the layer below if it is missing. 2031da177e4SLinus Torvalds */ 2041da177e4SLinus Torvalds if (!p->ary[m]) { 2054ae53789SNadia Derbey new = get_from_free_list(idp); 2064ae53789SNadia Derbey if (!new) 20712d1b439STejun Heo return -ENOMEM; 2086ff2d39bSManfred Spraul new->layer = l-1; 2093219b3b7SNadia Derbey rcu_assign_pointer(p->ary[m], new); 2101da177e4SLinus Torvalds p->count++; 2111da177e4SLinus Torvalds } 2121da177e4SLinus Torvalds pa[l--] = p; 2131da177e4SLinus Torvalds p = p->ary[m]; 2141da177e4SLinus Torvalds } 215e33ac8bdSTejun Heo 216e33ac8bdSTejun Heo pa[l] = p; 217e33ac8bdSTejun Heo return id; 2181da177e4SLinus Torvalds } 2191da177e4SLinus Torvalds 220e33ac8bdSTejun Heo static int idr_get_empty_slot(struct idr *idp, int starting_id, 221e33ac8bdSTejun Heo struct idr_layer **pa) 2221da177e4SLinus Torvalds { 2231da177e4SLinus Torvalds struct idr_layer *p, *new; 2241da177e4SLinus Torvalds int layers, v, id; 225c259cc28SRoland Dreier unsigned long flags; 2261da177e4SLinus Torvalds 2271da177e4SLinus Torvalds id = starting_id; 2281da177e4SLinus Torvalds build_up: 2291da177e4SLinus Torvalds p = idp->top; 2301da177e4SLinus Torvalds layers = idp->layers; 2311da177e4SLinus Torvalds if (unlikely(!p)) { 2324ae53789SNadia Derbey if (!(p = get_from_free_list(idp))) 23312d1b439STejun Heo return -ENOMEM; 2346ff2d39bSManfred Spraul p->layer = 0; 2351da177e4SLinus Torvalds layers = 1; 2361da177e4SLinus Torvalds } 2371da177e4SLinus Torvalds /* 2381da177e4SLinus Torvalds * Add a new layer to the top of the tree if the requested 2391da177e4SLinus Torvalds * id is larger than the currently allocated space. 2401da177e4SLinus Torvalds */ 241125c4c70SFengguang Wu while ((layers < (MAX_IDR_LEVEL - 1)) && (id >= (1 << (layers*IDR_BITS)))) { 2421da177e4SLinus Torvalds layers++; 243711a49a0SManfred Spraul if (!p->count) { 244711a49a0SManfred Spraul /* special case: if the tree is currently empty, 245711a49a0SManfred Spraul * then we grow the tree by moving the top node 246711a49a0SManfred Spraul * upwards. 247711a49a0SManfred Spraul */ 248711a49a0SManfred Spraul p->layer++; 2491da177e4SLinus Torvalds continue; 250711a49a0SManfred Spraul } 2514ae53789SNadia Derbey if (!(new = get_from_free_list(idp))) { 2521da177e4SLinus Torvalds /* 2531da177e4SLinus Torvalds * The allocation failed. If we built part of 2541da177e4SLinus Torvalds * the structure tear it down. 2551da177e4SLinus Torvalds */ 256c259cc28SRoland Dreier spin_lock_irqsave(&idp->lock, flags); 2571da177e4SLinus Torvalds for (new = p; p && p != idp->top; new = p) { 2581da177e4SLinus Torvalds p = p->ary[0]; 2591da177e4SLinus Torvalds new->ary[0] = NULL; 2601da177e4SLinus Torvalds new->bitmap = new->count = 0; 2614ae53789SNadia Derbey __move_to_free_list(idp, new); 2621da177e4SLinus Torvalds } 263c259cc28SRoland Dreier spin_unlock_irqrestore(&idp->lock, flags); 26412d1b439STejun Heo return -ENOMEM; 2651da177e4SLinus Torvalds } 2661da177e4SLinus Torvalds new->ary[0] = p; 2671da177e4SLinus Torvalds new->count = 1; 2686ff2d39bSManfred Spraul new->layer = layers-1; 2691da177e4SLinus Torvalds if (p->bitmap == IDR_FULL) 2701da177e4SLinus Torvalds __set_bit(0, &new->bitmap); 2711da177e4SLinus Torvalds p = new; 2721da177e4SLinus Torvalds } 2733219b3b7SNadia Derbey rcu_assign_pointer(idp->top, p); 2741da177e4SLinus Torvalds idp->layers = layers; 275e33ac8bdSTejun Heo v = sub_alloc(idp, &id, pa); 27612d1b439STejun Heo if (v == -EAGAIN) 2771da177e4SLinus Torvalds goto build_up; 2781da177e4SLinus Torvalds return(v); 2791da177e4SLinus Torvalds } 2801da177e4SLinus Torvalds 281e33ac8bdSTejun Heo /* 2823594eb28STejun Heo * @id and @pa are from a successful allocation from idr_get_empty_slot(). 2833594eb28STejun Heo * Install the user pointer @ptr and mark the slot full. 284e33ac8bdSTejun Heo */ 2853594eb28STejun Heo static void idr_fill_slot(void *ptr, int id, struct idr_layer **pa) 2863594eb28STejun Heo { 2873594eb28STejun Heo rcu_assign_pointer(pa[0]->ary[id & IDR_MASK], (struct idr_layer *)ptr); 288e33ac8bdSTejun Heo pa[0]->count++; 289e33ac8bdSTejun Heo idr_mark_full(pa, id); 290e33ac8bdSTejun Heo } 291e33ac8bdSTejun Heo 2921da177e4SLinus Torvalds /** 2937c657f2fSJohn McCutchan * idr_get_new_above - allocate new idr entry above or equal to a start id 2941da177e4SLinus Torvalds * @idp: idr handle 29594e2bd68SThadeu Lima de Souza Cascardo * @ptr: pointer you want associated with the id 296ea24ea85SNaohiro Aota * @starting_id: id to start search at 2971da177e4SLinus Torvalds * @id: pointer to the allocated handle 2981da177e4SLinus Torvalds * 2991da177e4SLinus Torvalds * This is the allocate id function. It should be called with any 3001da177e4SLinus Torvalds * required locks. 3011da177e4SLinus Torvalds * 302066a9be6SNaohiro Aota * If allocation from IDR's private freelist fails, idr_get_new_above() will 30356083ab1SRandy Dunlap * return %-EAGAIN. The caller should retry the idr_pre_get() call to refill 304066a9be6SNaohiro Aota * IDR's preallocation and then retry the idr_get_new_above() call. 305066a9be6SNaohiro Aota * 30656083ab1SRandy Dunlap * If the idr is full idr_get_new_above() will return %-ENOSPC. 3071da177e4SLinus Torvalds * 30856083ab1SRandy Dunlap * @id returns a value in the range @starting_id ... %0x7fffffff 3091da177e4SLinus Torvalds */ 3101da177e4SLinus Torvalds int idr_get_new_above(struct idr *idp, void *ptr, int starting_id, int *id) 3111da177e4SLinus Torvalds { 3123594eb28STejun Heo struct idr_layer *pa[MAX_IDR_LEVEL]; 3131da177e4SLinus Torvalds int rv; 314e15ae2ddSJesper Juhl 3153594eb28STejun Heo rv = idr_get_empty_slot(idp, starting_id, pa); 316944ca05cSNadia Derbey if (rv < 0) 31712d1b439STejun Heo return rv == -ENOMEM ? -EAGAIN : rv; 3183594eb28STejun Heo 3193594eb28STejun Heo idr_fill_slot(ptr, rv, pa); 3201da177e4SLinus Torvalds *id = rv; 3211da177e4SLinus Torvalds return 0; 3221da177e4SLinus Torvalds } 3231da177e4SLinus Torvalds EXPORT_SYMBOL(idr_get_new_above); 3241da177e4SLinus Torvalds 3251da177e4SLinus Torvalds static void idr_remove_warning(int id) 3261da177e4SLinus Torvalds { 327f098ad65SNadia Derbey printk(KERN_WARNING 328f098ad65SNadia Derbey "idr_remove called for id=%d which is not allocated.\n", id); 3291da177e4SLinus Torvalds dump_stack(); 3301da177e4SLinus Torvalds } 3311da177e4SLinus Torvalds 3321da177e4SLinus Torvalds static void sub_remove(struct idr *idp, int shift, int id) 3331da177e4SLinus Torvalds { 3341da177e4SLinus Torvalds struct idr_layer *p = idp->top; 335125c4c70SFengguang Wu struct idr_layer **pa[MAX_IDR_LEVEL]; 3361da177e4SLinus Torvalds struct idr_layer ***paa = &pa[0]; 337cf481c20SNadia Derbey struct idr_layer *to_free; 3381da177e4SLinus Torvalds int n; 3391da177e4SLinus Torvalds 3401da177e4SLinus Torvalds *paa = NULL; 3411da177e4SLinus Torvalds *++paa = &idp->top; 3421da177e4SLinus Torvalds 3431da177e4SLinus Torvalds while ((shift > 0) && p) { 3441da177e4SLinus Torvalds n = (id >> shift) & IDR_MASK; 3451da177e4SLinus Torvalds __clear_bit(n, &p->bitmap); 3461da177e4SLinus Torvalds *++paa = &p->ary[n]; 3471da177e4SLinus Torvalds p = p->ary[n]; 3481da177e4SLinus Torvalds shift -= IDR_BITS; 3491da177e4SLinus Torvalds } 3501da177e4SLinus Torvalds n = id & IDR_MASK; 3511da177e4SLinus Torvalds if (likely(p != NULL && test_bit(n, &p->bitmap))){ 3521da177e4SLinus Torvalds __clear_bit(n, &p->bitmap); 353cf481c20SNadia Derbey rcu_assign_pointer(p->ary[n], NULL); 354cf481c20SNadia Derbey to_free = NULL; 3551da177e4SLinus Torvalds while(*paa && ! --((**paa)->count)){ 356cf481c20SNadia Derbey if (to_free) 357cf481c20SNadia Derbey free_layer(to_free); 358cf481c20SNadia Derbey to_free = **paa; 3591da177e4SLinus Torvalds **paa-- = NULL; 3601da177e4SLinus Torvalds } 3611da177e4SLinus Torvalds if (!*paa) 3621da177e4SLinus Torvalds idp->layers = 0; 363cf481c20SNadia Derbey if (to_free) 364cf481c20SNadia Derbey free_layer(to_free); 365e15ae2ddSJesper Juhl } else 3661da177e4SLinus Torvalds idr_remove_warning(id); 3671da177e4SLinus Torvalds } 3681da177e4SLinus Torvalds 3691da177e4SLinus Torvalds /** 37056083ab1SRandy Dunlap * idr_remove - remove the given id and free its slot 37172fd4a35SRobert P. J. Day * @idp: idr handle 37272fd4a35SRobert P. J. Day * @id: unique key 3731da177e4SLinus Torvalds */ 3741da177e4SLinus Torvalds void idr_remove(struct idr *idp, int id) 3751da177e4SLinus Torvalds { 3761da177e4SLinus Torvalds struct idr_layer *p; 377cf481c20SNadia Derbey struct idr_layer *to_free; 3781da177e4SLinus Torvalds 3791da177e4SLinus Torvalds /* Mask off upper bits we don't use for the search. */ 380125c4c70SFengguang Wu id &= MAX_IDR_MASK; 3811da177e4SLinus Torvalds 3821da177e4SLinus Torvalds sub_remove(idp, (idp->layers - 1) * IDR_BITS, id); 383e15ae2ddSJesper Juhl if (idp->top && idp->top->count == 1 && (idp->layers > 1) && 384cf481c20SNadia Derbey idp->top->ary[0]) { 385cf481c20SNadia Derbey /* 386cf481c20SNadia Derbey * Single child at leftmost slot: we can shrink the tree. 387cf481c20SNadia Derbey * This level is not needed anymore since when layers are 388cf481c20SNadia Derbey * inserted, they are inserted at the top of the existing 389cf481c20SNadia Derbey * tree. 390cf481c20SNadia Derbey */ 391cf481c20SNadia Derbey to_free = idp->top; 3921da177e4SLinus Torvalds p = idp->top->ary[0]; 393cf481c20SNadia Derbey rcu_assign_pointer(idp->top, p); 3941da177e4SLinus Torvalds --idp->layers; 395cf481c20SNadia Derbey to_free->bitmap = to_free->count = 0; 396cf481c20SNadia Derbey free_layer(to_free); 3971da177e4SLinus Torvalds } 398125c4c70SFengguang Wu while (idp->id_free_cnt >= MAX_IDR_FREE) { 3994ae53789SNadia Derbey p = get_from_free_list(idp); 400cf481c20SNadia Derbey /* 401cf481c20SNadia Derbey * Note: we don't call the rcu callback here, since the only 402cf481c20SNadia Derbey * layers that fall into the freelist are those that have been 403cf481c20SNadia Derbey * preallocated. 404cf481c20SNadia Derbey */ 4051da177e4SLinus Torvalds kmem_cache_free(idr_layer_cache, p); 4061da177e4SLinus Torvalds } 407af8e2a4cSNadia Derbey return; 4081da177e4SLinus Torvalds } 4091da177e4SLinus Torvalds EXPORT_SYMBOL(idr_remove); 4101da177e4SLinus Torvalds 411fe6e24ecSTejun Heo void __idr_remove_all(struct idr *idp) 41223936cc0SKristian Hoegsberg { 4136ace06dcSOleg Nesterov int n, id, max; 4142dcb22b3SImre Deak int bt_mask; 41523936cc0SKristian Hoegsberg struct idr_layer *p; 416125c4c70SFengguang Wu struct idr_layer *pa[MAX_IDR_LEVEL]; 41723936cc0SKristian Hoegsberg struct idr_layer **paa = &pa[0]; 41823936cc0SKristian Hoegsberg 41923936cc0SKristian Hoegsberg n = idp->layers * IDR_BITS; 42023936cc0SKristian Hoegsberg p = idp->top; 4211b23336aSPaul E. McKenney rcu_assign_pointer(idp->top, NULL); 42223936cc0SKristian Hoegsberg max = 1 << n; 42323936cc0SKristian Hoegsberg 42423936cc0SKristian Hoegsberg id = 0; 4256ace06dcSOleg Nesterov while (id < max) { 42623936cc0SKristian Hoegsberg while (n > IDR_BITS && p) { 42723936cc0SKristian Hoegsberg n -= IDR_BITS; 42823936cc0SKristian Hoegsberg *paa++ = p; 42923936cc0SKristian Hoegsberg p = p->ary[(id >> n) & IDR_MASK]; 43023936cc0SKristian Hoegsberg } 43123936cc0SKristian Hoegsberg 4322dcb22b3SImre Deak bt_mask = id; 43323936cc0SKristian Hoegsberg id += 1 << n; 4342dcb22b3SImre Deak /* Get the highest bit that the above add changed from 0->1. */ 4352dcb22b3SImre Deak while (n < fls(id ^ bt_mask)) { 436cf481c20SNadia Derbey if (p) 437cf481c20SNadia Derbey free_layer(p); 43823936cc0SKristian Hoegsberg n += IDR_BITS; 43923936cc0SKristian Hoegsberg p = *--paa; 44023936cc0SKristian Hoegsberg } 44123936cc0SKristian Hoegsberg } 44223936cc0SKristian Hoegsberg idp->layers = 0; 44323936cc0SKristian Hoegsberg } 444fe6e24ecSTejun Heo EXPORT_SYMBOL(__idr_remove_all); 44523936cc0SKristian Hoegsberg 44623936cc0SKristian Hoegsberg /** 4478d3b3591SAndrew Morton * idr_destroy - release all cached layers within an idr tree 448ea24ea85SNaohiro Aota * @idp: idr handle 4499bb26bc1STejun Heo * 4509bb26bc1STejun Heo * Free all id mappings and all idp_layers. After this function, @idp is 4519bb26bc1STejun Heo * completely unused and can be freed / recycled. The caller is 4529bb26bc1STejun Heo * responsible for ensuring that no one else accesses @idp during or after 4539bb26bc1STejun Heo * idr_destroy(). 4549bb26bc1STejun Heo * 4559bb26bc1STejun Heo * A typical clean-up sequence for objects stored in an idr tree will use 4569bb26bc1STejun Heo * idr_for_each() to free all objects, if necessay, then idr_destroy() to 4579bb26bc1STejun Heo * free up the id mappings and cached idr_layers. 4588d3b3591SAndrew Morton */ 4598d3b3591SAndrew Morton void idr_destroy(struct idr *idp) 4608d3b3591SAndrew Morton { 461fe6e24ecSTejun Heo __idr_remove_all(idp); 4629bb26bc1STejun Heo 4638d3b3591SAndrew Morton while (idp->id_free_cnt) { 4644ae53789SNadia Derbey struct idr_layer *p = get_from_free_list(idp); 4658d3b3591SAndrew Morton kmem_cache_free(idr_layer_cache, p); 4668d3b3591SAndrew Morton } 4678d3b3591SAndrew Morton } 4688d3b3591SAndrew Morton EXPORT_SYMBOL(idr_destroy); 4698d3b3591SAndrew Morton 4708d3b3591SAndrew Morton /** 4711da177e4SLinus Torvalds * idr_find - return pointer for given id 4721da177e4SLinus Torvalds * @idp: idr handle 4731da177e4SLinus Torvalds * @id: lookup key 4741da177e4SLinus Torvalds * 4751da177e4SLinus Torvalds * Return the pointer given the id it has been registered with. A %NULL 4761da177e4SLinus Torvalds * return indicates that @id is not valid or you passed %NULL in 4771da177e4SLinus Torvalds * idr_get_new(). 4781da177e4SLinus Torvalds * 479f9c46d6eSNadia Derbey * This function can be called under rcu_read_lock(), given that the leaf 480f9c46d6eSNadia Derbey * pointers lifetimes are correctly managed. 4811da177e4SLinus Torvalds */ 4821da177e4SLinus Torvalds void *idr_find(struct idr *idp, int id) 4831da177e4SLinus Torvalds { 4841da177e4SLinus Torvalds int n; 4851da177e4SLinus Torvalds struct idr_layer *p; 4861da177e4SLinus Torvalds 48796be753aSPaul E. McKenney p = rcu_dereference_raw(idp->top); 4886ff2d39bSManfred Spraul if (!p) 4896ff2d39bSManfred Spraul return NULL; 4906ff2d39bSManfred Spraul n = (p->layer+1) * IDR_BITS; 4911da177e4SLinus Torvalds 4921da177e4SLinus Torvalds /* Mask off upper bits we don't use for the search. */ 493125c4c70SFengguang Wu id &= MAX_IDR_MASK; 4941da177e4SLinus Torvalds 4951da177e4SLinus Torvalds if (id >= (1 << n)) 4961da177e4SLinus Torvalds return NULL; 4976ff2d39bSManfred Spraul BUG_ON(n == 0); 4981da177e4SLinus Torvalds 4991da177e4SLinus Torvalds while (n > 0 && p) { 5001da177e4SLinus Torvalds n -= IDR_BITS; 5016ff2d39bSManfred Spraul BUG_ON(n != p->layer*IDR_BITS); 50296be753aSPaul E. McKenney p = rcu_dereference_raw(p->ary[(id >> n) & IDR_MASK]); 5031da177e4SLinus Torvalds } 5041da177e4SLinus Torvalds return((void *)p); 5051da177e4SLinus Torvalds } 5061da177e4SLinus Torvalds EXPORT_SYMBOL(idr_find); 5071da177e4SLinus Torvalds 5085806f07cSJeff Mahoney /** 50996d7fa42SKristian Hoegsberg * idr_for_each - iterate through all stored pointers 51096d7fa42SKristian Hoegsberg * @idp: idr handle 51196d7fa42SKristian Hoegsberg * @fn: function to be called for each pointer 51296d7fa42SKristian Hoegsberg * @data: data passed back to callback function 51396d7fa42SKristian Hoegsberg * 51496d7fa42SKristian Hoegsberg * Iterate over the pointers registered with the given idr. The 51596d7fa42SKristian Hoegsberg * callback function will be called for each pointer currently 51696d7fa42SKristian Hoegsberg * registered, passing the id, the pointer and the data pointer passed 51796d7fa42SKristian Hoegsberg * to this function. It is not safe to modify the idr tree while in 51896d7fa42SKristian Hoegsberg * the callback, so functions such as idr_get_new and idr_remove are 51996d7fa42SKristian Hoegsberg * not allowed. 52096d7fa42SKristian Hoegsberg * 52196d7fa42SKristian Hoegsberg * We check the return of @fn each time. If it returns anything other 52256083ab1SRandy Dunlap * than %0, we break out and return that value. 52396d7fa42SKristian Hoegsberg * 52496d7fa42SKristian Hoegsberg * The caller must serialize idr_for_each() vs idr_get_new() and idr_remove(). 52596d7fa42SKristian Hoegsberg */ 52696d7fa42SKristian Hoegsberg int idr_for_each(struct idr *idp, 52796d7fa42SKristian Hoegsberg int (*fn)(int id, void *p, void *data), void *data) 52896d7fa42SKristian Hoegsberg { 52996d7fa42SKristian Hoegsberg int n, id, max, error = 0; 53096d7fa42SKristian Hoegsberg struct idr_layer *p; 531125c4c70SFengguang Wu struct idr_layer *pa[MAX_IDR_LEVEL]; 53296d7fa42SKristian Hoegsberg struct idr_layer **paa = &pa[0]; 53396d7fa42SKristian Hoegsberg 53496d7fa42SKristian Hoegsberg n = idp->layers * IDR_BITS; 53596be753aSPaul E. McKenney p = rcu_dereference_raw(idp->top); 53696d7fa42SKristian Hoegsberg max = 1 << n; 53796d7fa42SKristian Hoegsberg 53896d7fa42SKristian Hoegsberg id = 0; 53996d7fa42SKristian Hoegsberg while (id < max) { 54096d7fa42SKristian Hoegsberg while (n > 0 && p) { 54196d7fa42SKristian Hoegsberg n -= IDR_BITS; 54296d7fa42SKristian Hoegsberg *paa++ = p; 54396be753aSPaul E. McKenney p = rcu_dereference_raw(p->ary[(id >> n) & IDR_MASK]); 54496d7fa42SKristian Hoegsberg } 54596d7fa42SKristian Hoegsberg 54696d7fa42SKristian Hoegsberg if (p) { 54796d7fa42SKristian Hoegsberg error = fn(id, (void *)p, data); 54896d7fa42SKristian Hoegsberg if (error) 54996d7fa42SKristian Hoegsberg break; 55096d7fa42SKristian Hoegsberg } 55196d7fa42SKristian Hoegsberg 55296d7fa42SKristian Hoegsberg id += 1 << n; 55396d7fa42SKristian Hoegsberg while (n < fls(id)) { 55496d7fa42SKristian Hoegsberg n += IDR_BITS; 55596d7fa42SKristian Hoegsberg p = *--paa; 55696d7fa42SKristian Hoegsberg } 55796d7fa42SKristian Hoegsberg } 55896d7fa42SKristian Hoegsberg 55996d7fa42SKristian Hoegsberg return error; 56096d7fa42SKristian Hoegsberg } 56196d7fa42SKristian Hoegsberg EXPORT_SYMBOL(idr_for_each); 56296d7fa42SKristian Hoegsberg 56396d7fa42SKristian Hoegsberg /** 56438460b48SKAMEZAWA Hiroyuki * idr_get_next - lookup next object of id to given id. 56538460b48SKAMEZAWA Hiroyuki * @idp: idr handle 566ea24ea85SNaohiro Aota * @nextidp: pointer to lookup key 56738460b48SKAMEZAWA Hiroyuki * 56838460b48SKAMEZAWA Hiroyuki * Returns pointer to registered object with id, which is next number to 5691458ce16SNaohiro Aota * given id. After being looked up, *@nextidp will be updated for the next 5701458ce16SNaohiro Aota * iteration. 5719f7de827SHugh Dickins * 5729f7de827SHugh Dickins * This function can be called under rcu_read_lock(), given that the leaf 5739f7de827SHugh Dickins * pointers lifetimes are correctly managed. 57438460b48SKAMEZAWA Hiroyuki */ 57538460b48SKAMEZAWA Hiroyuki void *idr_get_next(struct idr *idp, int *nextidp) 57638460b48SKAMEZAWA Hiroyuki { 577125c4c70SFengguang Wu struct idr_layer *p, *pa[MAX_IDR_LEVEL]; 57838460b48SKAMEZAWA Hiroyuki struct idr_layer **paa = &pa[0]; 57938460b48SKAMEZAWA Hiroyuki int id = *nextidp; 58038460b48SKAMEZAWA Hiroyuki int n, max; 58138460b48SKAMEZAWA Hiroyuki 58238460b48SKAMEZAWA Hiroyuki /* find first ent */ 58394bfa3b6SPaul E. McKenney p = rcu_dereference_raw(idp->top); 58438460b48SKAMEZAWA Hiroyuki if (!p) 58538460b48SKAMEZAWA Hiroyuki return NULL; 5869f7de827SHugh Dickins n = (p->layer + 1) * IDR_BITS; 5879f7de827SHugh Dickins max = 1 << n; 58838460b48SKAMEZAWA Hiroyuki 58938460b48SKAMEZAWA Hiroyuki while (id < max) { 59038460b48SKAMEZAWA Hiroyuki while (n > 0 && p) { 59138460b48SKAMEZAWA Hiroyuki n -= IDR_BITS; 59238460b48SKAMEZAWA Hiroyuki *paa++ = p; 59394bfa3b6SPaul E. McKenney p = rcu_dereference_raw(p->ary[(id >> n) & IDR_MASK]); 59438460b48SKAMEZAWA Hiroyuki } 59538460b48SKAMEZAWA Hiroyuki 59638460b48SKAMEZAWA Hiroyuki if (p) { 59738460b48SKAMEZAWA Hiroyuki *nextidp = id; 59838460b48SKAMEZAWA Hiroyuki return p; 59938460b48SKAMEZAWA Hiroyuki } 60038460b48SKAMEZAWA Hiroyuki 6016cdae741STejun Heo /* 6026cdae741STejun Heo * Proceed to the next layer at the current level. Unlike 6036cdae741STejun Heo * idr_for_each(), @id isn't guaranteed to be aligned to 6046cdae741STejun Heo * layer boundary at this point and adding 1 << n may 6056cdae741STejun Heo * incorrectly skip IDs. Make sure we jump to the 6066cdae741STejun Heo * beginning of the next layer using round_up(). 6076cdae741STejun Heo */ 6086cdae741STejun Heo id = round_up(id + 1, 1 << n); 60938460b48SKAMEZAWA Hiroyuki while (n < fls(id)) { 61038460b48SKAMEZAWA Hiroyuki n += IDR_BITS; 61138460b48SKAMEZAWA Hiroyuki p = *--paa; 61238460b48SKAMEZAWA Hiroyuki } 61338460b48SKAMEZAWA Hiroyuki } 61438460b48SKAMEZAWA Hiroyuki return NULL; 61538460b48SKAMEZAWA Hiroyuki } 6164d1ee80fSBen Hutchings EXPORT_SYMBOL(idr_get_next); 61738460b48SKAMEZAWA Hiroyuki 61838460b48SKAMEZAWA Hiroyuki 61938460b48SKAMEZAWA Hiroyuki /** 6205806f07cSJeff Mahoney * idr_replace - replace pointer for given id 6215806f07cSJeff Mahoney * @idp: idr handle 6225806f07cSJeff Mahoney * @ptr: pointer you want associated with the id 6235806f07cSJeff Mahoney * @id: lookup key 6245806f07cSJeff Mahoney * 6255806f07cSJeff Mahoney * Replace the pointer registered with an id and return the old value. 62656083ab1SRandy Dunlap * A %-ENOENT return indicates that @id was not found. 62756083ab1SRandy Dunlap * A %-EINVAL return indicates that @id was not within valid constraints. 6285806f07cSJeff Mahoney * 629cf481c20SNadia Derbey * The caller must serialize with writers. 6305806f07cSJeff Mahoney */ 6315806f07cSJeff Mahoney void *idr_replace(struct idr *idp, void *ptr, int id) 6325806f07cSJeff Mahoney { 6335806f07cSJeff Mahoney int n; 6345806f07cSJeff Mahoney struct idr_layer *p, *old_p; 6355806f07cSJeff Mahoney 6365806f07cSJeff Mahoney p = idp->top; 6376ff2d39bSManfred Spraul if (!p) 6386ff2d39bSManfred Spraul return ERR_PTR(-EINVAL); 6396ff2d39bSManfred Spraul 6406ff2d39bSManfred Spraul n = (p->layer+1) * IDR_BITS; 6415806f07cSJeff Mahoney 642125c4c70SFengguang Wu id &= MAX_IDR_MASK; 6435806f07cSJeff Mahoney 6445806f07cSJeff Mahoney if (id >= (1 << n)) 6455806f07cSJeff Mahoney return ERR_PTR(-EINVAL); 6465806f07cSJeff Mahoney 6475806f07cSJeff Mahoney n -= IDR_BITS; 6485806f07cSJeff Mahoney while ((n > 0) && p) { 6495806f07cSJeff Mahoney p = p->ary[(id >> n) & IDR_MASK]; 6505806f07cSJeff Mahoney n -= IDR_BITS; 6515806f07cSJeff Mahoney } 6525806f07cSJeff Mahoney 6535806f07cSJeff Mahoney n = id & IDR_MASK; 6545806f07cSJeff Mahoney if (unlikely(p == NULL || !test_bit(n, &p->bitmap))) 6555806f07cSJeff Mahoney return ERR_PTR(-ENOENT); 6565806f07cSJeff Mahoney 6575806f07cSJeff Mahoney old_p = p->ary[n]; 658cf481c20SNadia Derbey rcu_assign_pointer(p->ary[n], ptr); 6595806f07cSJeff Mahoney 6605806f07cSJeff Mahoney return old_p; 6615806f07cSJeff Mahoney } 6625806f07cSJeff Mahoney EXPORT_SYMBOL(idr_replace); 6635806f07cSJeff Mahoney 664199f0ca5SAkinobu Mita void __init idr_init_cache(void) 6651da177e4SLinus Torvalds { 6661da177e4SLinus Torvalds idr_layer_cache = kmem_cache_create("idr_layer_cache", 6675b019e99SAndrew Morton sizeof(struct idr_layer), 0, SLAB_PANIC, NULL); 6681da177e4SLinus Torvalds } 6691da177e4SLinus Torvalds 6701da177e4SLinus Torvalds /** 6711da177e4SLinus Torvalds * idr_init - initialize idr handle 6721da177e4SLinus Torvalds * @idp: idr handle 6731da177e4SLinus Torvalds * 6741da177e4SLinus Torvalds * This function is use to set up the handle (@idp) that you will pass 6751da177e4SLinus Torvalds * to the rest of the functions. 6761da177e4SLinus Torvalds */ 6771da177e4SLinus Torvalds void idr_init(struct idr *idp) 6781da177e4SLinus Torvalds { 6791da177e4SLinus Torvalds memset(idp, 0, sizeof(struct idr)); 6801da177e4SLinus Torvalds spin_lock_init(&idp->lock); 6811da177e4SLinus Torvalds } 6821da177e4SLinus Torvalds EXPORT_SYMBOL(idr_init); 68372dba584STejun Heo 68472dba584STejun Heo 68556083ab1SRandy Dunlap /** 68656083ab1SRandy Dunlap * DOC: IDA description 68772dba584STejun Heo * IDA - IDR based ID allocator 68872dba584STejun Heo * 68956083ab1SRandy Dunlap * This is id allocator without id -> pointer translation. Memory 69072dba584STejun Heo * usage is much lower than full blown idr because each id only 69172dba584STejun Heo * occupies a bit. ida uses a custom leaf node which contains 69272dba584STejun Heo * IDA_BITMAP_BITS slots. 69372dba584STejun Heo * 69472dba584STejun Heo * 2007-04-25 written by Tejun Heo <htejun@gmail.com> 69572dba584STejun Heo */ 69672dba584STejun Heo 69772dba584STejun Heo static void free_bitmap(struct ida *ida, struct ida_bitmap *bitmap) 69872dba584STejun Heo { 69972dba584STejun Heo unsigned long flags; 70072dba584STejun Heo 70172dba584STejun Heo if (!ida->free_bitmap) { 70272dba584STejun Heo spin_lock_irqsave(&ida->idr.lock, flags); 70372dba584STejun Heo if (!ida->free_bitmap) { 70472dba584STejun Heo ida->free_bitmap = bitmap; 70572dba584STejun Heo bitmap = NULL; 70672dba584STejun Heo } 70772dba584STejun Heo spin_unlock_irqrestore(&ida->idr.lock, flags); 70872dba584STejun Heo } 70972dba584STejun Heo 71072dba584STejun Heo kfree(bitmap); 71172dba584STejun Heo } 71272dba584STejun Heo 71372dba584STejun Heo /** 71472dba584STejun Heo * ida_pre_get - reserve resources for ida allocation 71572dba584STejun Heo * @ida: ida handle 71672dba584STejun Heo * @gfp_mask: memory allocation flag 71772dba584STejun Heo * 71872dba584STejun Heo * This function should be called prior to locking and calling the 71972dba584STejun Heo * following function. It preallocates enough memory to satisfy the 72072dba584STejun Heo * worst possible allocation. 72172dba584STejun Heo * 72256083ab1SRandy Dunlap * If the system is REALLY out of memory this function returns %0, 72356083ab1SRandy Dunlap * otherwise %1. 72472dba584STejun Heo */ 72572dba584STejun Heo int ida_pre_get(struct ida *ida, gfp_t gfp_mask) 72672dba584STejun Heo { 72772dba584STejun Heo /* allocate idr_layers */ 72872dba584STejun Heo if (!idr_pre_get(&ida->idr, gfp_mask)) 72972dba584STejun Heo return 0; 73072dba584STejun Heo 73172dba584STejun Heo /* allocate free_bitmap */ 73272dba584STejun Heo if (!ida->free_bitmap) { 73372dba584STejun Heo struct ida_bitmap *bitmap; 73472dba584STejun Heo 73572dba584STejun Heo bitmap = kmalloc(sizeof(struct ida_bitmap), gfp_mask); 73672dba584STejun Heo if (!bitmap) 73772dba584STejun Heo return 0; 73872dba584STejun Heo 73972dba584STejun Heo free_bitmap(ida, bitmap); 74072dba584STejun Heo } 74172dba584STejun Heo 74272dba584STejun Heo return 1; 74372dba584STejun Heo } 74472dba584STejun Heo EXPORT_SYMBOL(ida_pre_get); 74572dba584STejun Heo 74672dba584STejun Heo /** 74772dba584STejun Heo * ida_get_new_above - allocate new ID above or equal to a start id 74872dba584STejun Heo * @ida: ida handle 749ea24ea85SNaohiro Aota * @starting_id: id to start search at 75072dba584STejun Heo * @p_id: pointer to the allocated handle 75172dba584STejun Heo * 752e3816c54SWang Sheng-Hui * Allocate new ID above or equal to @starting_id. It should be called 753e3816c54SWang Sheng-Hui * with any required locks. 75472dba584STejun Heo * 75556083ab1SRandy Dunlap * If memory is required, it will return %-EAGAIN, you should unlock 75672dba584STejun Heo * and go back to the ida_pre_get() call. If the ida is full, it will 75756083ab1SRandy Dunlap * return %-ENOSPC. 75872dba584STejun Heo * 75956083ab1SRandy Dunlap * @p_id returns a value in the range @starting_id ... %0x7fffffff. 76072dba584STejun Heo */ 76172dba584STejun Heo int ida_get_new_above(struct ida *ida, int starting_id, int *p_id) 76272dba584STejun Heo { 763125c4c70SFengguang Wu struct idr_layer *pa[MAX_IDR_LEVEL]; 76472dba584STejun Heo struct ida_bitmap *bitmap; 76572dba584STejun Heo unsigned long flags; 76672dba584STejun Heo int idr_id = starting_id / IDA_BITMAP_BITS; 76772dba584STejun Heo int offset = starting_id % IDA_BITMAP_BITS; 76872dba584STejun Heo int t, id; 76972dba584STejun Heo 77072dba584STejun Heo restart: 77172dba584STejun Heo /* get vacant slot */ 77272dba584STejun Heo t = idr_get_empty_slot(&ida->idr, idr_id, pa); 773944ca05cSNadia Derbey if (t < 0) 77412d1b439STejun Heo return t == -ENOMEM ? -EAGAIN : t; 77572dba584STejun Heo 776125c4c70SFengguang Wu if (t * IDA_BITMAP_BITS >= MAX_IDR_BIT) 77772dba584STejun Heo return -ENOSPC; 77872dba584STejun Heo 77972dba584STejun Heo if (t != idr_id) 78072dba584STejun Heo offset = 0; 78172dba584STejun Heo idr_id = t; 78272dba584STejun Heo 78372dba584STejun Heo /* if bitmap isn't there, create a new one */ 78472dba584STejun Heo bitmap = (void *)pa[0]->ary[idr_id & IDR_MASK]; 78572dba584STejun Heo if (!bitmap) { 78672dba584STejun Heo spin_lock_irqsave(&ida->idr.lock, flags); 78772dba584STejun Heo bitmap = ida->free_bitmap; 78872dba584STejun Heo ida->free_bitmap = NULL; 78972dba584STejun Heo spin_unlock_irqrestore(&ida->idr.lock, flags); 79072dba584STejun Heo 79172dba584STejun Heo if (!bitmap) 79272dba584STejun Heo return -EAGAIN; 79372dba584STejun Heo 79472dba584STejun Heo memset(bitmap, 0, sizeof(struct ida_bitmap)); 7953219b3b7SNadia Derbey rcu_assign_pointer(pa[0]->ary[idr_id & IDR_MASK], 7963219b3b7SNadia Derbey (void *)bitmap); 79772dba584STejun Heo pa[0]->count++; 79872dba584STejun Heo } 79972dba584STejun Heo 80072dba584STejun Heo /* lookup for empty slot */ 80172dba584STejun Heo t = find_next_zero_bit(bitmap->bitmap, IDA_BITMAP_BITS, offset); 80272dba584STejun Heo if (t == IDA_BITMAP_BITS) { 80372dba584STejun Heo /* no empty slot after offset, continue to the next chunk */ 80472dba584STejun Heo idr_id++; 80572dba584STejun Heo offset = 0; 80672dba584STejun Heo goto restart; 80772dba584STejun Heo } 80872dba584STejun Heo 80972dba584STejun Heo id = idr_id * IDA_BITMAP_BITS + t; 810125c4c70SFengguang Wu if (id >= MAX_IDR_BIT) 81172dba584STejun Heo return -ENOSPC; 81272dba584STejun Heo 81372dba584STejun Heo __set_bit(t, bitmap->bitmap); 81472dba584STejun Heo if (++bitmap->nr_busy == IDA_BITMAP_BITS) 81572dba584STejun Heo idr_mark_full(pa, idr_id); 81672dba584STejun Heo 81772dba584STejun Heo *p_id = id; 81872dba584STejun Heo 81972dba584STejun Heo /* Each leaf node can handle nearly a thousand slots and the 82072dba584STejun Heo * whole idea of ida is to have small memory foot print. 82172dba584STejun Heo * Throw away extra resources one by one after each successful 82272dba584STejun Heo * allocation. 82372dba584STejun Heo */ 82472dba584STejun Heo if (ida->idr.id_free_cnt || ida->free_bitmap) { 8254ae53789SNadia Derbey struct idr_layer *p = get_from_free_list(&ida->idr); 82672dba584STejun Heo if (p) 82772dba584STejun Heo kmem_cache_free(idr_layer_cache, p); 82872dba584STejun Heo } 82972dba584STejun Heo 83072dba584STejun Heo return 0; 83172dba584STejun Heo } 83272dba584STejun Heo EXPORT_SYMBOL(ida_get_new_above); 83372dba584STejun Heo 83472dba584STejun Heo /** 83572dba584STejun Heo * ida_remove - remove the given ID 83672dba584STejun Heo * @ida: ida handle 83772dba584STejun Heo * @id: ID to free 83872dba584STejun Heo */ 83972dba584STejun Heo void ida_remove(struct ida *ida, int id) 84072dba584STejun Heo { 84172dba584STejun Heo struct idr_layer *p = ida->idr.top; 84272dba584STejun Heo int shift = (ida->idr.layers - 1) * IDR_BITS; 84372dba584STejun Heo int idr_id = id / IDA_BITMAP_BITS; 84472dba584STejun Heo int offset = id % IDA_BITMAP_BITS; 84572dba584STejun Heo int n; 84672dba584STejun Heo struct ida_bitmap *bitmap; 84772dba584STejun Heo 84872dba584STejun Heo /* clear full bits while looking up the leaf idr_layer */ 84972dba584STejun Heo while ((shift > 0) && p) { 85072dba584STejun Heo n = (idr_id >> shift) & IDR_MASK; 85172dba584STejun Heo __clear_bit(n, &p->bitmap); 85272dba584STejun Heo p = p->ary[n]; 85372dba584STejun Heo shift -= IDR_BITS; 85472dba584STejun Heo } 85572dba584STejun Heo 85672dba584STejun Heo if (p == NULL) 85772dba584STejun Heo goto err; 85872dba584STejun Heo 85972dba584STejun Heo n = idr_id & IDR_MASK; 86072dba584STejun Heo __clear_bit(n, &p->bitmap); 86172dba584STejun Heo 86272dba584STejun Heo bitmap = (void *)p->ary[n]; 86372dba584STejun Heo if (!test_bit(offset, bitmap->bitmap)) 86472dba584STejun Heo goto err; 86572dba584STejun Heo 86672dba584STejun Heo /* update bitmap and remove it if empty */ 86772dba584STejun Heo __clear_bit(offset, bitmap->bitmap); 86872dba584STejun Heo if (--bitmap->nr_busy == 0) { 86972dba584STejun Heo __set_bit(n, &p->bitmap); /* to please idr_remove() */ 87072dba584STejun Heo idr_remove(&ida->idr, idr_id); 87172dba584STejun Heo free_bitmap(ida, bitmap); 87272dba584STejun Heo } 87372dba584STejun Heo 87472dba584STejun Heo return; 87572dba584STejun Heo 87672dba584STejun Heo err: 87772dba584STejun Heo printk(KERN_WARNING 87872dba584STejun Heo "ida_remove called for id=%d which is not allocated.\n", id); 87972dba584STejun Heo } 88072dba584STejun Heo EXPORT_SYMBOL(ida_remove); 88172dba584STejun Heo 88272dba584STejun Heo /** 88372dba584STejun Heo * ida_destroy - release all cached layers within an ida tree 884ea24ea85SNaohiro Aota * @ida: ida handle 88572dba584STejun Heo */ 88672dba584STejun Heo void ida_destroy(struct ida *ida) 88772dba584STejun Heo { 88872dba584STejun Heo idr_destroy(&ida->idr); 88972dba584STejun Heo kfree(ida->free_bitmap); 89072dba584STejun Heo } 89172dba584STejun Heo EXPORT_SYMBOL(ida_destroy); 89272dba584STejun Heo 89372dba584STejun Heo /** 89488eca020SRusty Russell * ida_simple_get - get a new id. 89588eca020SRusty Russell * @ida: the (initialized) ida. 89688eca020SRusty Russell * @start: the minimum id (inclusive, < 0x8000000) 89788eca020SRusty Russell * @end: the maximum id (exclusive, < 0x8000000 or 0) 89888eca020SRusty Russell * @gfp_mask: memory allocation flags 89988eca020SRusty Russell * 90088eca020SRusty Russell * Allocates an id in the range start <= id < end, or returns -ENOSPC. 90188eca020SRusty Russell * On memory allocation failure, returns -ENOMEM. 90288eca020SRusty Russell * 90388eca020SRusty Russell * Use ida_simple_remove() to get rid of an id. 90488eca020SRusty Russell */ 90588eca020SRusty Russell int ida_simple_get(struct ida *ida, unsigned int start, unsigned int end, 90688eca020SRusty Russell gfp_t gfp_mask) 90788eca020SRusty Russell { 90888eca020SRusty Russell int ret, id; 90988eca020SRusty Russell unsigned int max; 91046cbc1d3STejun Heo unsigned long flags; 91188eca020SRusty Russell 91288eca020SRusty Russell BUG_ON((int)start < 0); 91388eca020SRusty Russell BUG_ON((int)end < 0); 91488eca020SRusty Russell 91588eca020SRusty Russell if (end == 0) 91688eca020SRusty Russell max = 0x80000000; 91788eca020SRusty Russell else { 91888eca020SRusty Russell BUG_ON(end < start); 91988eca020SRusty Russell max = end - 1; 92088eca020SRusty Russell } 92188eca020SRusty Russell 92288eca020SRusty Russell again: 92388eca020SRusty Russell if (!ida_pre_get(ida, gfp_mask)) 92488eca020SRusty Russell return -ENOMEM; 92588eca020SRusty Russell 92646cbc1d3STejun Heo spin_lock_irqsave(&simple_ida_lock, flags); 92788eca020SRusty Russell ret = ida_get_new_above(ida, start, &id); 92888eca020SRusty Russell if (!ret) { 92988eca020SRusty Russell if (id > max) { 93088eca020SRusty Russell ida_remove(ida, id); 93188eca020SRusty Russell ret = -ENOSPC; 93288eca020SRusty Russell } else { 93388eca020SRusty Russell ret = id; 93488eca020SRusty Russell } 93588eca020SRusty Russell } 93646cbc1d3STejun Heo spin_unlock_irqrestore(&simple_ida_lock, flags); 93788eca020SRusty Russell 93888eca020SRusty Russell if (unlikely(ret == -EAGAIN)) 93988eca020SRusty Russell goto again; 94088eca020SRusty Russell 94188eca020SRusty Russell return ret; 94288eca020SRusty Russell } 94388eca020SRusty Russell EXPORT_SYMBOL(ida_simple_get); 94488eca020SRusty Russell 94588eca020SRusty Russell /** 94688eca020SRusty Russell * ida_simple_remove - remove an allocated id. 94788eca020SRusty Russell * @ida: the (initialized) ida. 94888eca020SRusty Russell * @id: the id returned by ida_simple_get. 94988eca020SRusty Russell */ 95088eca020SRusty Russell void ida_simple_remove(struct ida *ida, unsigned int id) 95188eca020SRusty Russell { 95246cbc1d3STejun Heo unsigned long flags; 95346cbc1d3STejun Heo 95488eca020SRusty Russell BUG_ON((int)id < 0); 95546cbc1d3STejun Heo spin_lock_irqsave(&simple_ida_lock, flags); 95688eca020SRusty Russell ida_remove(ida, id); 95746cbc1d3STejun Heo spin_unlock_irqrestore(&simple_ida_lock, flags); 95888eca020SRusty Russell } 95988eca020SRusty Russell EXPORT_SYMBOL(ida_simple_remove); 96088eca020SRusty Russell 96188eca020SRusty Russell /** 96272dba584STejun Heo * ida_init - initialize ida handle 96372dba584STejun Heo * @ida: ida handle 96472dba584STejun Heo * 96572dba584STejun Heo * This function is use to set up the handle (@ida) that you will pass 96672dba584STejun Heo * to the rest of the functions. 96772dba584STejun Heo */ 96872dba584STejun Heo void ida_init(struct ida *ida) 96972dba584STejun Heo { 97072dba584STejun Heo memset(ida, 0, sizeof(struct ida)); 97172dba584STejun Heo idr_init(&ida->idr); 97272dba584STejun Heo 97372dba584STejun Heo } 97472dba584STejun Heo EXPORT_SYMBOL(ida_init); 975