Only neigh_for_each() and neigh_seq_start/stop() are on the reader side of neigh_table.lock. Let's convert rwlock to the plain spinlock. Signed-off-by: Kuniyuki Iwashima --- include/net/neighbour.h | 2 +- net/atm/clip.c | 4 +-- net/core/neighbour.c | 68 +++++++++++++++++++++-------------------- net/ipv4/arp.c | 4 +-- 4 files changed, 40 insertions(+), 38 deletions(-) diff --git a/include/net/neighbour.h b/include/net/neighbour.h index 998ff9eccebb7..2dfee6d4258af 100644 --- a/include/net/neighbour.h +++ b/include/net/neighbour.h @@ -238,7 +238,7 @@ struct neigh_table { atomic_t gc_entries; struct list_head gc_list; struct list_head managed_list; - rwlock_t lock; + spinlock_t lock; unsigned long last_rand; struct neigh_statistics __percpu *stats; struct neigh_hash_table __rcu *nht; diff --git a/net/atm/clip.c b/net/atm/clip.c index f7a5565e794ef..8f152e5fa6594 100644 --- a/net/atm/clip.c +++ b/net/atm/clip.c @@ -168,10 +168,10 @@ static int neigh_check_cb(struct neighbour *n) static void idle_timer_check(struct timer_list *unused) { - write_lock(&arp_tbl.lock); + spin_lock(&arp_tbl.lock); __neigh_for_each_release(&arp_tbl, neigh_check_cb); mod_timer(&idle_timer, jiffies + CLIP_CHECK_INTERVAL * HZ); - write_unlock(&arp_tbl.lock); + spin_unlock(&arp_tbl.lock); } static int clip_arp_rcv(struct sk_buff *skb) diff --git a/net/core/neighbour.c b/net/core/neighbour.c index 807a0d2457728..bb2a35f6cfe44 100644 --- a/net/core/neighbour.c +++ b/net/core/neighbour.c @@ -81,7 +81,7 @@ static struct hlist_head *neigh_get_dev_table(struct net_device *dev, int family } /* - Neighbour hash table buckets are protected with rwlock tbl->lock. + Neighbour hash table buckets are protected with tbl->lock. - All the scans/updates to hash buckets MUST be made under this lock. - NOTHING clever should be made under this lock: no callbacks @@ -149,7 +149,7 @@ static void neigh_update_gc_list(struct neighbour *n) { bool on_gc_list, exempt_from_gc; - write_lock_bh(&n->tbl->lock); + spin_lock_bh(&n->tbl->lock); write_lock(&n->lock); if (n->dead) goto out; @@ -172,14 +172,14 @@ static void neigh_update_gc_list(struct neighbour *n) } out: write_unlock(&n->lock); - write_unlock_bh(&n->tbl->lock); + spin_unlock_bh(&n->tbl->lock); } static void neigh_update_managed_list(struct neighbour *n) { bool on_managed_list, add_to_managed; - write_lock_bh(&n->tbl->lock); + spin_lock_bh(&n->tbl->lock); write_lock(&n->lock); if (n->dead) goto out; @@ -193,7 +193,7 @@ static void neigh_update_managed_list(struct neighbour *n) list_add_tail(&n->managed_list, &n->tbl->managed_list); out: write_unlock(&n->lock); - write_unlock_bh(&n->tbl->lock); + spin_unlock_bh(&n->tbl->lock); } static void neigh_update_flags(struct neighbour *neigh, u32 flags, int *notify, @@ -263,7 +263,7 @@ static int neigh_forced_gc(struct neigh_table *tbl) NEIGH_CACHE_STAT_INC(tbl, forced_gc_runs); - write_lock_bh(&tbl->lock); + spin_lock_bh(&tbl->lock); list_for_each_entry_safe(n, tmp, &tbl->gc_list, gc_list) { if (refcount_read(&n->refcnt) == 1) { @@ -292,7 +292,7 @@ static int neigh_forced_gc(struct neigh_table *tbl) WRITE_ONCE(tbl->last_flush, jiffies); unlock: - write_unlock_bh(&tbl->lock); + spin_unlock_bh(&tbl->lock); return shrunk; } @@ -454,23 +454,23 @@ static void neigh_flush_table(struct neigh_table *tbl) void neigh_changeaddr(struct neigh_table *tbl, struct net_device *dev) { - write_lock_bh(&tbl->lock); + spin_lock_bh(&tbl->lock); neigh_flush_dev(tbl, dev, false); - write_unlock_bh(&tbl->lock); + spin_unlock_bh(&tbl->lock); } EXPORT_SYMBOL(neigh_changeaddr); static int __neigh_ifdown(struct neigh_table *tbl, struct net_device *dev, bool skip_perm) { - write_lock_bh(&tbl->lock); + spin_lock_bh(&tbl->lock); if (likely(dev)) { neigh_flush_dev(tbl, dev, skip_perm); } else { DEBUG_NET_WARN_ON_ONCE(skip_perm); neigh_flush_table(tbl); } - write_unlock_bh(&tbl->lock); + spin_unlock_bh(&tbl->lock); pneigh_ifdown(tbl, dev, skip_perm); pneigh_queue_purge(&tbl->proxy_queue, dev ? dev_net(dev) : NULL, @@ -687,7 +687,7 @@ ___neigh_create(struct neigh_table *tbl, const void *pkey, n->confirmed = jiffies - (NEIGH_VAR(n->parms, BASE_REACHABLE_TIME) << 1); - write_lock_bh(&tbl->lock); + spin_lock_bh(&tbl->lock); nht = rcu_dereference_protected(tbl->nht, lockdep_is_held(&tbl->lock)); @@ -722,13 +722,13 @@ ___neigh_create(struct neigh_table *tbl, const void *pkey, hlist_add_head_rcu(&n->dev_list, neigh_get_dev_table(dev, tbl->family)); - write_unlock_bh(&tbl->lock); + spin_unlock_bh(&tbl->lock); neigh_dbg(2, "neigh %p is created\n", n); rc = n; out: return rc; out_tbl_unlock: - write_unlock_bh(&tbl->lock); + spin_unlock_bh(&tbl->lock); out_neigh_release: if (!exempt_from_gc) atomic_dec(&tbl->gc_entries); @@ -982,7 +982,7 @@ static void neigh_periodic_work(struct work_struct *work) NEIGH_CACHE_STAT_INC(tbl, periodic_gc_runs); - write_lock_bh(&tbl->lock); + spin_lock_bh(&tbl->lock); nht = rcu_dereference_protected(tbl->nht, lockdep_is_held(&tbl->lock)); @@ -1036,9 +1036,9 @@ static void neigh_periodic_work(struct work_struct *work) * It's fine to release lock here, even if hash table * grows while we are preempted. */ - write_unlock_bh(&tbl->lock); + spin_unlock_bh(&tbl->lock); cond_resched(); - write_lock_bh(&tbl->lock); + spin_lock_bh(&tbl->lock); nht = rcu_dereference_protected(tbl->nht, lockdep_is_held(&tbl->lock)); } @@ -1049,7 +1049,7 @@ static void neigh_periodic_work(struct work_struct *work) */ queue_delayed_work(system_power_efficient_wq, &tbl->gc_work, NEIGH_VAR(&tbl->parms, BASE_REACHABLE_TIME) >> 1); - write_unlock_bh(&tbl->lock); + spin_unlock_bh(&tbl->lock); } static __inline__ int neigh_max_probes(struct neighbour *n) @@ -1641,12 +1641,12 @@ static void neigh_managed_work(struct work_struct *work) managed_work.work); struct neighbour *neigh; - write_lock_bh(&tbl->lock); + spin_lock_bh(&tbl->lock); list_for_each_entry(neigh, &tbl->managed_list, managed_list) neigh_event_send_probe(neigh, NULL, false); queue_delayed_work(system_power_efficient_wq, &tbl->managed_work, NEIGH_VAR(&tbl->parms, INTERVAL_PROBE_TIME_MS)); - write_unlock_bh(&tbl->lock); + spin_unlock_bh(&tbl->lock); } static void neigh_proxy_process(struct timer_list *t) @@ -1761,9 +1761,9 @@ struct neigh_parms *neigh_parms_alloc(struct net_device *dev, return NULL; } - write_lock_bh(&tbl->lock); + spin_lock_bh(&tbl->lock); list_add_rcu(&p->list, &tbl->parms.list); - write_unlock_bh(&tbl->lock); + spin_unlock_bh(&tbl->lock); neigh_parms_data_state_cleanall(p); } @@ -1783,10 +1783,12 @@ void neigh_parms_release(struct neigh_table *tbl, struct neigh_parms *parms) { if (!parms || parms == &tbl->parms) return; - write_lock_bh(&tbl->lock); + + spin_lock_bh(&tbl->lock); list_del_rcu(&parms->list); parms->dead = 1; - write_unlock_bh(&tbl->lock); + spin_unlock_bh(&tbl->lock); + netdev_put(parms->dev, &parms->dev_tracker); call_rcu(&parms->rcu_head, neigh_rcu_free_parms); } @@ -1835,7 +1837,7 @@ void neigh_table_init(int index, struct neigh_table *tbl) else WARN_ON(tbl->entry_size % NEIGH_PRIV_ALIGN); - rwlock_init(&tbl->lock); + spin_lock_init(&tbl->lock); mutex_init(&tbl->phash_lock); INIT_DEFERRABLE_WORK(&tbl->gc_work, neigh_periodic_work); @@ -1978,10 +1980,10 @@ static int neigh_delete(struct sk_buff *skb, struct nlmsghdr *nlh, err = __neigh_update(neigh, NULL, NUD_FAILED, NEIGH_UPDATE_F_OVERRIDE | NEIGH_UPDATE_F_ADMIN, NETLINK_CB(skb).portid, extack); - write_lock_bh(&tbl->lock); + spin_lock_bh(&tbl->lock); neigh_release(neigh); neigh_remove_one(neigh); - write_unlock_bh(&tbl->lock); + spin_unlock_bh(&tbl->lock); out: return err; @@ -2406,7 +2408,7 @@ static int neightbl_set(struct sk_buff *skb, struct nlmsghdr *nlh, * We acquire tbl->lock to be nice to the periodic timers and * make sure they always see a consistent set of values. */ - write_lock_bh(&tbl->lock); + spin_lock_bh(&tbl->lock); if (tb[NDTA_PARMS]) { struct nlattr *tbp[NDTPA_MAX+1]; @@ -2525,7 +2527,7 @@ static int neightbl_set(struct sk_buff *skb, struct nlmsghdr *nlh, err = 0; errout_tbl_lock: - write_unlock_bh(&tbl->lock); + spin_unlock_bh(&tbl->lock); rcu_read_unlock(); errout: return err; @@ -3125,14 +3127,14 @@ void neigh_for_each(struct neigh_table *tbl, void (*cb)(struct neighbour *, void rcu_read_lock(); nht = rcu_dereference(tbl->nht); - read_lock_bh(&tbl->lock); /* avoid resizes */ + spin_lock_bh(&tbl->lock); /* avoid resizes */ for (chain = 0; chain < (1 << nht->hash_shift); chain++) { struct neighbour *n; neigh_for_each_in_bucket(n, &nht->hash_heads[chain]) cb(n, cookie); } - read_unlock_bh(&tbl->lock); + spin_unlock_bh(&tbl->lock); rcu_read_unlock(); } EXPORT_SYMBOL(neigh_for_each); @@ -3402,7 +3404,7 @@ void *neigh_seq_start(struct seq_file *seq, loff_t *pos, struct neigh_table *tbl rcu_read_lock(); state->nht = rcu_dereference(tbl->nht); - read_lock_bh(&tbl->lock); + spin_lock_bh(&tbl->lock); return *pos ? neigh_get_idx_any(seq, pos) : SEQ_START_TOKEN; } @@ -3442,7 +3444,7 @@ void neigh_seq_stop(struct seq_file *seq, void *v) struct neigh_seq_state *state = seq->private; struct neigh_table *tbl = state->tbl; - read_unlock_bh(&tbl->lock); + spin_unlock_bh(&tbl->lock); rcu_read_unlock(); } EXPORT_SYMBOL(neigh_seq_stop); diff --git a/net/ipv4/arp.c b/net/ipv4/arp.c index 833f2cf97178e..f3bfecf8a2341 100644 --- a/net/ipv4/arp.c +++ b/net/ipv4/arp.c @@ -1217,10 +1217,10 @@ int arp_invalidate(struct net_device *dev, __be32 ip, bool force) err = neigh_update(neigh, NULL, NUD_FAILED, NEIGH_UPDATE_F_OVERRIDE| NEIGH_UPDATE_F_ADMIN, 0); - write_lock_bh(&tbl->lock); + spin_lock_bh(&tbl->lock); neigh_release(neigh); neigh_remove_one(neigh); - write_unlock_bh(&tbl->lock); + spin_unlock_bh(&tbl->lock); } return err; -- 2.51.0.915.g61a8936c21-goog