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1// SPDX-License-Identifier: GPL-2.0-or-later2/*3 * Copyright (c) 2004 Evgeniy Polyakov <zbr@ioremap.net>4 */5 6#include <linux/spinlock.h>7#include <linux/list.h>8#include <linux/sched/signal.h>9#include <linux/delay.h>10#include <linux/export.h>11 12#include "w1_internal.h"13 14DEFINE_SPINLOCK(w1_flock);15static LIST_HEAD(w1_families);16 17/**18 * w1_register_family() - register a device family driver19 * @newf: family to register20 */21int w1_register_family(struct w1_family *newf)22{23 struct list_head *ent, *n;24 struct w1_family *f;25 int ret = 0;26 27 spin_lock(&w1_flock);28 list_for_each_safe(ent, n, &w1_families) {29 f = list_entry(ent, struct w1_family, family_entry);30 31 if (f->fid == newf->fid) {32 ret = -EEXIST;33 break;34 }35 }36 37 if (!ret) {38 atomic_set(&newf->refcnt, 0);39 list_add_tail(&newf->family_entry, &w1_families);40 }41 spin_unlock(&w1_flock);42 43 /* check default devices against the new set of drivers */44 w1_reconnect_slaves(newf, 1);45 46 return ret;47}48EXPORT_SYMBOL(w1_register_family);49 50/**51 * w1_unregister_family() - unregister a device family driver52 * @fent: family to unregister53 */54void w1_unregister_family(struct w1_family *fent)55{56 struct list_head *ent, *n;57 struct w1_family *f;58 59 spin_lock(&w1_flock);60 list_for_each_safe(ent, n, &w1_families) {61 f = list_entry(ent, struct w1_family, family_entry);62 63 if (f->fid == fent->fid) {64 list_del(&fent->family_entry);65 break;66 }67 }68 spin_unlock(&w1_flock);69 70 /* deatch devices using this family code */71 w1_reconnect_slaves(fent, 0);72 73 while (atomic_read(&fent->refcnt)) {74 pr_info("Waiting for family %u to become free: refcnt=%d.\n",75 fent->fid, atomic_read(&fent->refcnt));76 77 if (msleep_interruptible(1000))78 flush_signals(current);79 }80}81EXPORT_SYMBOL(w1_unregister_family);82 83/*84 * Should be called under w1_flock held.85 */86struct w1_family * w1_family_registered(u8 fid)87{88 struct list_head *ent, *n;89 struct w1_family *f = NULL;90 int ret = 0;91 92 list_for_each_safe(ent, n, &w1_families) {93 f = list_entry(ent, struct w1_family, family_entry);94 95 if (f->fid == fid) {96 ret = 1;97 break;98 }99 }100 101 return (ret) ? f : NULL;102}103 104static void __w1_family_put(struct w1_family *f)105{106 atomic_dec(&f->refcnt);107}108 109void w1_family_put(struct w1_family *f)110{111 spin_lock(&w1_flock);112 __w1_family_put(f);113 spin_unlock(&w1_flock);114}115 116#if 0117void w1_family_get(struct w1_family *f)118{119 spin_lock(&w1_flock);120 __w1_family_get(f);121 spin_unlock(&w1_flock);122}123#endif /* 0 */124 125void __w1_family_get(struct w1_family *f)126{127 smp_mb__before_atomic();128 atomic_inc(&f->refcnt);129 smp_mb__after_atomic();130}131