diff options
author | Eric Dumazet <edumazet@google.com> | 2022-06-23 07:34:49 +0300 |
---|---|---|
committer | David S. Miller <davem@davemloft.net> | 2022-06-24 13:34:38 +0300 |
commit | a96f7a6a60b310fdb7913d5ae70961eeeca9527d (patch) | |
tree | 5c00956ca95472c1a3196f5b74f4396e5b44abb2 /net | |
parent | 3f55211ecf6a8fb271565adcb704cd57a8e4547c (diff) | |
download | linux-a96f7a6a60b310fdb7913d5ae70961eeeca9527d.tar.xz |
ip6mr: convert mrt_lock to a spinlock
mrt_lock is only held in write mode, from process context only.
We can switch to a mere spinlock, and avoid blocking BH.
Also, vif_dev_read() is always called under standard rcu_read_lock().
Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net')
-rw-r--r-- | net/ipv6/ip6mr.c | 29 |
1 files changed, 14 insertions, 15 deletions
diff --git a/net/ipv6/ip6mr.c b/net/ipv6/ip6mr.c index 7381cfdac3e3..ec6e1509fc7c 100644 --- a/net/ipv6/ip6mr.c +++ b/net/ipv6/ip6mr.c @@ -62,12 +62,11 @@ struct ip6mr_result { Note that the changes are semaphored via rtnl_lock. */ -static DEFINE_RWLOCK(mrt_lock); +static DEFINE_SPINLOCK(mrt_lock); static struct net_device *vif_dev_read(const struct vif_device *vif) { - return rcu_dereference_check(vif->dev, - lockdep_is_held(&mrt_lock)); + return rcu_dereference(vif->dev); } /* Multicast router control variables */ @@ -714,7 +713,7 @@ static int mif6_delete(struct mr_table *mrt, int vifi, int notify, call_ip6mr_vif_entry_notifiers(read_pnet(&mrt->net), FIB_EVENT_VIF_DEL, v, dev, vifi, mrt->id); - write_lock_bh(&mrt_lock); + spin_lock(&mrt_lock); RCU_INIT_POINTER(v->dev, NULL); #ifdef CONFIG_IPV6_PIMSM_V2 @@ -733,7 +732,7 @@ static int mif6_delete(struct mr_table *mrt, int vifi, int notify, WRITE_ONCE(mrt->maxvif, tmp + 1); } - write_unlock_bh(&mrt_lock); + spin_unlock(&mrt_lock); dev_set_allmulti(dev, -1); @@ -833,7 +832,7 @@ static void ipmr_expire_process(struct timer_list *t) spin_unlock(&mfc_unres_lock); } -/* Fill oifs list. It is called under write locked mrt_lock. */ +/* Fill oifs list. It is called under locked mrt_lock. */ static void ip6mr_update_thresholds(struct mr_table *mrt, struct mr_mfc *cache, @@ -919,7 +918,7 @@ static int mif6_add(struct net *net, struct mr_table *mrt, MIFF_REGISTER); /* And finish update writing critical data */ - write_lock_bh(&mrt_lock); + spin_lock(&mrt_lock); rcu_assign_pointer(v->dev, dev); netdev_tracker_alloc(dev, &v->dev_tracker, GFP_ATOMIC); #ifdef CONFIG_IPV6_PIMSM_V2 @@ -928,7 +927,7 @@ static int mif6_add(struct net *net, struct mr_table *mrt, #endif if (vifi + 1 > mrt->maxvif) WRITE_ONCE(mrt->maxvif, vifi + 1); - write_unlock_bh(&mrt_lock); + spin_unlock(&mrt_lock); call_ip6mr_vif_entry_notifiers(net, FIB_EVENT_VIF_ADD, v, dev, vifi, mrt->id); return 0; @@ -1442,12 +1441,12 @@ static int ip6mr_mfc_add(struct net *net, struct mr_table *mrt, &mfc->mf6cc_mcastgrp.sin6_addr, parent); rcu_read_unlock(); if (c) { - write_lock_bh(&mrt_lock); + spin_lock(&mrt_lock); c->_c.mfc_parent = mfc->mf6cc_parent; ip6mr_update_thresholds(mrt, &c->_c, ttls); if (!mrtsock) c->_c.mfc_flags |= MFC_STATIC; - write_unlock_bh(&mrt_lock); + spin_unlock(&mrt_lock); call_ip6mr_mfc_entry_notifiers(net, FIB_EVENT_ENTRY_REPLACE, c, mrt->id); mr6_netlink_event(mrt, c, RTM_NEWROUTE); @@ -1565,7 +1564,7 @@ static int ip6mr_sk_init(struct mr_table *mrt, struct sock *sk) struct net *net = sock_net(sk); rtnl_lock(); - write_lock_bh(&mrt_lock); + spin_lock(&mrt_lock); if (rtnl_dereference(mrt->mroute_sk)) { err = -EADDRINUSE; } else { @@ -1573,7 +1572,7 @@ static int ip6mr_sk_init(struct mr_table *mrt, struct sock *sk) sock_set_flag(sk, SOCK_RCU_FREE); atomic_inc(&net->ipv6.devconf_all->mc_forwarding); } - write_unlock_bh(&mrt_lock); + spin_unlock(&mrt_lock); if (!err) inet6_netconf_notify_devconf(net, RTM_NEWNETCONF, @@ -1603,14 +1602,14 @@ int ip6mr_sk_done(struct sock *sk) rtnl_lock(); ip6mr_for_each_table(mrt, net) { if (sk == rtnl_dereference(mrt->mroute_sk)) { - write_lock_bh(&mrt_lock); + spin_lock(&mrt_lock); RCU_INIT_POINTER(mrt->mroute_sk, NULL); /* Note that mroute_sk had SOCK_RCU_FREE set, * so the RCU grace period before sk freeing * is guaranteed by sk_destruct() */ atomic_dec(&devconf->mc_forwarding); - write_unlock_bh(&mrt_lock); + spin_unlock(&mrt_lock); inet6_netconf_notify_devconf(net, RTM_NEWNETCONF, NETCONFA_MC_FORWARDING, NETCONFA_IFINDEX_ALL, @@ -2097,7 +2096,7 @@ out_free: return 0; } -/* Called with mrt_lock or rcu_read_lock() */ +/* Called with rcu_read_lock() */ static int ip6mr_find_vif(struct mr_table *mrt, struct net_device *dev) { int ct; |