From 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 Mon Sep 17 00:00:00 2001 From: Linus Torvalds Date: Sat, 16 Apr 2005 15:20:36 -0700 Subject: Linux-2.6.12-rc2 Initial git repository build. I'm not bothering with the full history, even though we have it. We can create a separate "historical" git archive of that later if we want to, and in the meantime it's about 3.2GB when imported into git - space that would just make the early git days unnecessarily complicated, when we don't have a lot of good infrastructure for it. Let it rip! --- drivers/w1/w1_family.c | 150 +++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 150 insertions(+) create mode 100644 drivers/w1/w1_family.c (limited to 'drivers/w1/w1_family.c') diff --git a/drivers/w1/w1_family.c b/drivers/w1/w1_family.c new file mode 100644 index 00000000000..d1d56eca106 --- /dev/null +++ b/drivers/w1/w1_family.c @@ -0,0 +1,150 @@ +/* + * w1_family.c + * + * Copyright (c) 2004 Evgeniy Polyakov + * + * + * 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 +#include +#include + +#include "w1_family.h" + +DEFINE_SPINLOCK(w1_flock); +static LIST_HEAD(w1_families); + +static int w1_check_family(struct w1_family *f) +{ + if (!f->fops->rname || !f->fops->rbin || !f->fops->rval || !f->fops->rvalname) + return -EINVAL; + + return 0; +} + +int w1_register_family(struct w1_family *newf) +{ + struct list_head *ent, *n; + struct w1_family *f; + int ret = 0; + + if (w1_check_family(newf)) + return -EINVAL; + + 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); + + 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; +} + +void w1_family_put(struct w1_family *f) +{ + spin_lock(&w1_flock); + __w1_family_put(f); + spin_unlock(&w1_flock); +} + +void __w1_family_put(struct w1_family *f) +{ + if (atomic_dec_and_test(&f->refcnt)) + f->need_exit = 1; +} + +void w1_family_get(struct w1_family *f) +{ + spin_lock(&w1_flock); + __w1_family_get(f); + spin_unlock(&w1_flock); + +} + +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_family_get); +EXPORT_SYMBOL(w1_family_put); +EXPORT_SYMBOL(w1_family_registered); +EXPORT_SYMBOL(w1_unregister_family); +EXPORT_SYMBOL(w1_register_family); -- cgit v1.2.3