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// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Copyright (c) 2004 Evgeniy Polyakov <zbr@ioremap.net>
*/
#include <linux/spinlock.h>
#include <linux/list.h>
#include <linux/sched/signal.h>
#include <linux/delay.h>
#include <linux/export.h>
#include "w1_internal.h"
DEFINE_SPINLOCK(w1_flock);
static LIST_HEAD(w1_families);
/**
* w1_register_family() - register a device family driver
* @newf: family to register
*/
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);
list_add_tail(&newf->family_entry, &w1_families);
}
spin_unlock(&w1_flock);
/* check default devices against the new set of drivers */
w1_reconnect_slaves(newf, 1);
return ret;
}
EXPORT_SYMBOL(w1_register_family);
/**
* w1_unregister_family() - unregister a device family driver
* @fent: family to unregister
*/
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;
}
}
spin_unlock(&w1_flock);
/* deatch devices using this family code */
w1_reconnect_slaves(fent, 0);
while (atomic_read(&fent->refcnt)) {
pr_info("Waiting for family %u to become free: refcnt=%d.\n",
fent->fid, atomic_read(&fent->refcnt));
if (msleep_interruptible(1000))
flush_signals(current);
}
}
EXPORT_SYMBOL(w1_unregister_family);
/*
* 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)
{
atomic_dec(&f->refcnt);
}
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();
atomic_inc(&f->refcnt);
smp_mb__after_atomic();
}
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