/* * w1_family.c * * Copyright (c) 2004 Evgeniy Polyakov <johnpol@2ka.mipt.ru> * * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License as published by * the Free Software Foundation; either version 2 of the License, or * (at your option) any later version. * * 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 the Free Software * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */ #include <linux/spinlock.h> #include <linux/list.h> #include <linux/sched.h> /* schedule_timeout() */ #include <linux/delay.h> #include "w1_family.h" #include "w1.h" DEFINE_SPINLOCK(w1_flock); static LIST_HEAD(w1_families); int w1_register_family(struct w1_family *newf) { struct list_head *ent, *n; struct w1_family *f; int ret = 0; spin_lock(&w1_flock); list_for_each_safe(ent, n, &w1_families) { f = list_entry(ent, struct w1_family, family_entry); if (f->fid == newf->fid) { ret = -EEXIST; break; } } if (!ret) { atomic_set(&newf->refcnt, 0); newf->need_exit = 0; list_add_tail(&newf->family_entry, &w1_families); } spin_unlock(&w1_flock); w1_reconnect_slaves(newf); return ret; } void w1_unregister_family(struct w1_family *fent) { struct list_head *ent, *n; struct w1_family *f; spin_lock(&w1_flock); list_for_each_safe(ent, n, &w1_families) { f = list_entry(ent, struct w1_family, family_entry); if (f->fid == fent->fid) { list_del(&fent->family_entry); break; } } fent->need_exit = 1; spin_unlock(&w1_flock); while (atomic_read(&fent->refcnt)) { printk(KERN_INFO "Waiting for family %u to become free: refcnt=%d.\n", fent->fid, atomic_read(&fent->refcnt)); if (msleep_interruptible(1000)) flush_signals(current); } } /* * Should be called under w1_flock held. */ struct w1_family * w1_family_registered(u8 fid) { struct list_head *ent, *n; struct w1_family *f = NULL; int ret = 0; list_for_each_safe(ent, n, &w1_families) { f = list_entry(ent, struct w1_family, family_entry); if (f->fid == fid) { ret = 1; break; } } return (ret) ? f : NULL; } static void __w1_family_put(struct w1_family *f) { if (atomic_dec_and_test(&f->refcnt)) f->need_exit = 1; } void w1_family_put(struct w1_family *f) { spin_lock(&w1_flock); __w1_family_put(f); spin_unlock(&w1_flock); } #if 0 void w1_family_get(struct w1_family *f) { spin_lock(&w1_flock); __w1_family_get(f); spin_unlock(&w1_flock); } #endif /* 0 */ void __w1_family_get(struct w1_family *f) { smp_mb__before_atomic_inc(); atomic_inc(&f->refcnt); smp_mb__after_atomic_inc(); } EXPORT_SYMBOL(w1_unregister_family); EXPORT_SYMBOL(w1_register_family);