linux-stable/drivers/w1/w1_family.c
Thomas Gleixner c942fddf87 treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 157
Based on 3 normalized pattern(s):

  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

  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 [author] [kishon] [vijay] [abraham]
  [i] [kishon]@[ti] [com] 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

  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 [author] [graeme] [gregory]
  [gg]@[slimlogic] [co] [uk] [author] [kishon] [vijay] [abraham] [i]
  [kishon]@[ti] [com] [based] [on] [twl6030]_[usb] [c] [author] [hema]
  [hk] [hemahk]@[ti] [com] 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

extracted by the scancode license scanner the SPDX license identifier

  GPL-2.0-or-later

has been chosen to replace the boilerplate/reference in 1105 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Allison Randal <allison@lohutok.net>
Reviewed-by: Richard Fontana <rfontana@redhat.com>
Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190527070033.202006027@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-05-30 11:26:37 -07:00

130 lines
2.5 KiB
C

// 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();
}