1 /* 2 * net/9p/util.c 3 * 4 * This file contains some helper functions 5 * 6 * Copyright (C) 2007 by Latchesar Ionkov <lucho@ionkov.net> 7 * Copyright (C) 2004 by Eric Van Hensbergen <ericvh@gmail.com> 8 * Copyright (C) 2002 by Ron Minnich <rminnich@lanl.gov> 9 * 10 * This program is free software; you can redistribute it and/or modify 11 * it under the terms of the GNU General Public License version 2 12 * as published by the Free Software Foundation. 13 * 14 * This program is distributed in the hope that it will be useful, 15 * but WITHOUT ANY WARRANTY; without even the implied warranty of 16 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 17 * GNU General Public License for more details. 18 * 19 * You should have received a copy of the GNU General Public License 20 * along with this program; if not, write to: 21 * Free Software Foundation 22 * 51 Franklin Street, Fifth Floor 23 * Boston, MA 02111-1301 USA 24 * 25 */ 26 27 #include <linux/module.h> 28 #include <linux/errno.h> 29 #include <linux/fs.h> 30 #include <linux/sched.h> 31 #include <linux/parser.h> 32 #include <linux/idr.h> 33 #include <linux/slab.h> 34 #include <net/9p/9p.h> 35 36 /** 37 * struct p9_idpool - per-connection accounting for tag idpool 38 * @lock: protects the pool 39 * @pool: idr to allocate tag id from 40 * 41 */ 42 43 struct p9_idpool { 44 spinlock_t lock; 45 struct idr pool; 46 }; 47 48 /** 49 * p9_idpool_create - create a new per-connection id pool 50 * 51 */ 52 p9_idpool_create(void)53 struct p9_idpool *p9_idpool_create(void) 54 { 55 struct p9_idpool *p; 56 57 p = kmalloc(sizeof(struct p9_idpool), GFP_KERNEL); 58 if (!p) 59 return ERR_PTR(-ENOMEM); 60 61 spin_lock_init(&p->lock); 62 idr_init(&p->pool); 63 64 return p; 65 } 66 EXPORT_SYMBOL(p9_idpool_create); 67 68 /** 69 * p9_idpool_destroy - create a new per-connection id pool 70 * @p: idpool to destroy 71 */ 72 p9_idpool_destroy(struct p9_idpool * p)73 void p9_idpool_destroy(struct p9_idpool *p) 74 { 75 idr_destroy(&p->pool); 76 kfree(p); 77 } 78 EXPORT_SYMBOL(p9_idpool_destroy); 79 80 /** 81 * p9_idpool_get - allocate numeric id from pool 82 * @p: pool to allocate from 83 * 84 * Bugs: This seems to be an awful generic function, should it be in idr.c with 85 * the lock included in struct idr? 86 */ 87 p9_idpool_get(struct p9_idpool * p)88 int p9_idpool_get(struct p9_idpool *p) 89 { 90 int i; 91 unsigned long flags; 92 93 idr_preload(GFP_NOFS); 94 spin_lock_irqsave(&p->lock, flags); 95 96 /* no need to store exactly p, we just need something non-null */ 97 i = idr_alloc(&p->pool, p, 0, 0, GFP_NOWAIT); 98 99 spin_unlock_irqrestore(&p->lock, flags); 100 idr_preload_end(); 101 if (i < 0) 102 return -1; 103 104 p9_debug(P9_DEBUG_MUX, " id %d pool %p\n", i, p); 105 return i; 106 } 107 EXPORT_SYMBOL(p9_idpool_get); 108 109 /** 110 * p9_idpool_put - release numeric id from pool 111 * @id: numeric id which is being released 112 * @p: pool to release id into 113 * 114 * Bugs: This seems to be an awful generic function, should it be in idr.c with 115 * the lock included in struct idr? 116 */ 117 p9_idpool_put(int id,struct p9_idpool * p)118 void p9_idpool_put(int id, struct p9_idpool *p) 119 { 120 unsigned long flags; 121 122 p9_debug(P9_DEBUG_MUX, " id %d pool %p\n", id, p); 123 124 spin_lock_irqsave(&p->lock, flags); 125 idr_remove(&p->pool, id); 126 spin_unlock_irqrestore(&p->lock, flags); 127 } 128 EXPORT_SYMBOL(p9_idpool_put); 129 130 /** 131 * p9_idpool_check - check if the specified id is available 132 * @id: id to check 133 * @p: pool to check 134 */ 135 p9_idpool_check(int id,struct p9_idpool * p)136 int p9_idpool_check(int id, struct p9_idpool *p) 137 { 138 return idr_find(&p->pool, id) != NULL; 139 } 140 EXPORT_SYMBOL(p9_idpool_check); 141 142