/* * 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; unsigned long flags; idr_preload(GFP_NOFS); spin_lock_irqsave(&p->lock, flags); /* no need to store exactly p, we just need something non-null */ i = idr_alloc(&p->pool, p, 0, 0, GFP_NOWAIT); spin_unlock_irqrestore(&p->lock, flags); idr_preload_end(); if (i < 0) 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);