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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 | /* * net/9p/util.c * * This file contains some helper functions * * Copyright (C) 2007 by Latchesar Ionkov <lucho@ionkov.net> * Copyright (C) 2004 by Eric Van Hensbergen <ericvh@gmail.com> * Copyright (C) 2002 by Ron Minnich <rminnich@lanl.gov> * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License version 2 * as published by the Free Software Foundation. * * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to: * Free Software Foundation * 51 Franklin Street, Fifth Floor * Boston, MA 02111-1301 USA * */ #include <linux/module.h> #include <linux/errno.h> #include <linux/fs.h> #include <linux/sched.h> #include <linux/parser.h> #include <linux/idr.h> #include <linux/slab.h> #include <net/9p/9p.h> /** * struct p9_idpool - per-connection accounting for tag idpool * @lock: protects the pool * @pool: idr to allocate tag id from * */ struct p9_idpool { spinlock_t lock; struct idr pool; }; /** * p9_idpool_create - create a new per-connection id pool * */ struct p9_idpool *p9_idpool_create(void) { struct p9_idpool *p; p = kmalloc(sizeof(struct p9_idpool), GFP_KERNEL); if (!p) return ERR_PTR(-ENOMEM); spin_lock_init(&p->lock); idr_init(&p->pool); return p; } EXPORT_SYMBOL(p9_idpool_create); /** * p9_idpool_destroy - create a new per-connection id pool * @p: idpool to destroy */ void p9_idpool_destroy(struct p9_idpool *p) { idr_destroy(&p->pool); kfree(p); } EXPORT_SYMBOL(p9_idpool_destroy); /** * p9_idpool_get - allocate numeric id from pool * @p: pool to allocate from * * Bugs: This seems to be an awful generic function, should it be in idr.c with * the lock included in struct idr? */ int p9_idpool_get(struct p9_idpool *p) { int i = 0; int error; unsigned long flags; retry: if (idr_pre_get(&p->pool, GFP_NOFS) == 0) return -1; spin_lock_irqsave(&p->lock, flags); /* no need to store exactly p, we just need something non-null */ error = idr_get_new(&p->pool, p, &i); spin_unlock_irqrestore(&p->lock, flags); if (error == -EAGAIN) goto retry; else if (error) return -1; p9_debug(P9_DEBUG_MUX, " id %d pool %p\n", i, p); return i; } EXPORT_SYMBOL(p9_idpool_get); /** * p9_idpool_put - release numeric id from pool * @id: numeric id which is being released * @p: pool to release id into * * Bugs: This seems to be an awful generic function, should it be in idr.c with * the lock included in struct idr? */ void p9_idpool_put(int id, struct p9_idpool *p) { unsigned long flags; p9_debug(P9_DEBUG_MUX, " id %d pool %p\n", id, p); spin_lock_irqsave(&p->lock, flags); idr_remove(&p->pool, id); spin_unlock_irqrestore(&p->lock, flags); } EXPORT_SYMBOL(p9_idpool_put); /** * p9_idpool_check - check if the specified id is available * @id: id to check * @p: pool to check */ int p9_idpool_check(int id, struct p9_idpool *p) { return idr_find(&p->pool, id) != NULL; } EXPORT_SYMBOL(p9_idpool_check); |