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1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 | // 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(); } |