Merge branch 'pernet-all-async'

Kirill Tkhai says:

====================
Make pernet_operations always read locked

All the pernet_operations are converted, and the last one
is in this patchset (nfsd_net_ops acked by J. Bruce Fields).
So, it's the time to kill pernet_operations::async field,
and make setup_net() and cleanup_net() always require
the rwsem only read locked.

All further pernet_operations have to be developed to fit
this rule. Some of previous patches added a comment to
struct pernet_operations about that.

Also, this patchset renames net_sem to pernet_ops_rwsem
to make the target area of the rwsem is more clear visible,
and adds more comments.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/infiniband/core/cma.c

@@ -4554,7 +4554,6 @@ static struct pernet_operations cma_pernet_operations = {
 	.exit = cma_exit_net,
 	.id = &cma_pernet_id,
 	.size = sizeof(struct cma_pernet),
-	.async = true,
 };
 
 static int __init cma_init(void)

drivers/net/bonding/bond_main.c

@@ -4791,7 +4791,6 @@ static struct pernet_operations bond_net_ops = {
 	.exit = bond_net_exit,
 	.id   = &bond_net_id,
 	.size = sizeof(struct bond_net),
-	.async = true,
 };
 
 static int __init bonding_init(void)

drivers/net/geneve.c

@@ -1694,7 +1694,6 @@ static struct pernet_operations geneve_net_ops = {
 	.exit_batch = geneve_exit_batch_net,
 	.id   = &geneve_net_id,
 	.size = sizeof(struct geneve_net),
-	.async = true,
 };
 
 static int __init geneve_init_module(void)

drivers/net/gtp.c

@@ -1325,7 +1325,6 @@ static struct pernet_operations gtp_net_ops = {
 	.exit	= gtp_net_exit,
 	.id	= &gtp_net_id,
 	.size	= sizeof(struct gtp_net),
-	.async	= true,
 };
 
 static int __init gtp_init(void)

drivers/net/ipvlan/ipvlan_main.c

@@ -1040,7 +1040,6 @@ static struct pernet_operations ipvlan_net_ops = {
 	.id = &ipvlan_netid,
 	.size = sizeof(struct ipvlan_netns),
 	.exit = ipvlan_ns_exit,
-	.async = true,
 };
 
 static int __init ipvlan_init_module(void)

drivers/net/loopback.c

@@ -230,5 +230,4 @@ static __net_init int loopback_net_init(struct net *net)
 /* Registered in net/core/dev.c */
 struct pernet_operations __net_initdata loopback_net_ops = {
 	.init = loopback_net_init,
-	.async = true,
 };

drivers/net/ppp/ppp_generic.c

@@ -970,7 +970,6 @@ static struct pernet_operations ppp_net_ops = {
 	.exit = ppp_exit_net,
 	.id   = &ppp_net_id,
 	.size = sizeof(struct ppp_net),
-	.async = true,
 };
 
 static int ppp_unit_register(struct ppp *ppp, int unit, bool ifname_is_set)

drivers/net/ppp/pppoe.c

@@ -1161,7 +1161,6 @@ static struct pernet_operations pppoe_net_ops = {
 	.exit = pppoe_exit_net,
 	.id   = &pppoe_net_id,
 	.size = sizeof(struct pppoe_net),
-	.async = true,
 };
 
 static int __init pppoe_init(void)

drivers/net/vrf.c

@@ -1435,7 +1435,6 @@ static struct pernet_operations vrf_net_ops __net_initdata = {
 	.init = vrf_netns_init,
 	.id   = &vrf_net_id,
 	.size = sizeof(bool),
-	.async = true,
 };
 
 static int __init vrf_init_module(void)

drivers/net/vxlan.c

@@ -3752,7 +3752,6 @@ static struct pernet_operations vxlan_net_ops = {
 	.exit_batch = vxlan_exit_batch_net,
 	.id   = &vxlan_net_id,
 	.size = sizeof(struct vxlan_net),
-	.async = true,
 };
 
 static int __init vxlan_init_module(void)

drivers/net/wireless/mac80211_hwsim.c

@@ -3542,7 +3542,6 @@ static struct pernet_operations hwsim_net_ops = {
 	.exit = hwsim_exit_net,
 	.id   = &hwsim_net_id,
 	.size = sizeof(struct hwsim_net),
-	.async = true,
 };
 
 static void hwsim_exit_netlink(void)

fs/lockd/svc.c

@@ -709,7 +709,6 @@ static struct pernet_operations lockd_net_ops = {
 	.exit = lockd_exit_net,
 	.id = &lockd_net_id,
 	.size = sizeof(struct lockd_net),
-	.async = true,
 };
 
 

fs/nfs/blocklayout/rpc_pipefs.c

@@ -261,7 +261,6 @@ static void nfs4blocklayout_net_exit(struct net *net)
 static struct pernet_operations nfs4blocklayout_net_ops = {
 	.init = nfs4blocklayout_net_init,
 	.exit = nfs4blocklayout_net_exit,
-	.async = true,
 };
 
 int __init bl_init_pipefs(void)

fs/nfs/dns_resolve.c

@@ -410,7 +410,6 @@ static void nfs4_dns_net_exit(struct net *net)
 static struct pernet_operations nfs4_dns_resolver_ops = {
 	.init = nfs4_dns_net_init,
 	.exit = nfs4_dns_net_exit,
-	.async = true,
 };
 
 static int rpc_pipefs_event(struct notifier_block *nb, unsigned long event,

fs/nfs/inode.c

@@ -2122,7 +2122,6 @@ static struct pernet_operations nfs_net_ops = {
 	.exit = nfs_net_exit,
 	.id   = &nfs_net_id,
 	.size = sizeof(struct nfs_net),
-	.async = true,
 };
 
 /*

fs/nfs_common/grace.c

@@ -118,7 +118,6 @@ static struct pernet_operations grace_net_ops = {
 	.exit = grace_exit_net,
 	.id   = &grace_net_id,
 	.size = sizeof(struct list_head),
-	.async = true,
 };
 
 static int __init

fs/proc/proc_net.c

@@ -237,7 +237,6 @@ static __net_exit void proc_net_ns_exit(struct net *net)
 static struct pernet_operations __net_initdata proc_net_ns_ops = {
 	.init = proc_net_ns_init,
 	.exit = proc_net_ns_exit,
-	.async = true,
 };
 
 int __init proc_net_init(void)

include/linux/rtnetlink.h

@@ -36,7 +36,7 @@ extern int rtnl_is_locked(void);
 extern int rtnl_lock_killable(void);
 
 extern wait_queue_head_t netdev_unregistering_wq;
-extern struct rw_semaphore net_sem;
+extern struct rw_semaphore pernet_ops_rwsem;
 
 #ifdef CONFIG_PROVE_LOCKING
 extern bool lockdep_rtnl_is_held(void);

include/net/net_namespace.h

@@ -60,9 +60,10 @@ struct net {
 
 	struct list_head	list;		/* list of network namespaces */
 	struct list_head	exit_list;	/* To linked to call pernet exit
-						 * methods on dead net (net_sem
-						 * read locked), or to unregister
-						 * pernet ops (net_sem wr locked).
+						 * methods on dead net (
+						 * pernet_ops_rwsem read locked),
+						 * or to unregister pernet ops
+						 * (pernet_ops_rwsem write locked).
 						 */
 	struct llist_node	cleanup_list;	/* namespaces on death row */
 
@@ -95,8 +96,9 @@ struct net {
 	/* core fib_rules */
 	struct list_head	rules_ops;
 
-	struct list_head	fib_notifier_ops;  /* protected by net_sem */
-
+	struct list_head	fib_notifier_ops;  /* Populated by
+						    * register_pernet_subsys()
+						    */
 	struct net_device       *loopback_dev;          /* The loopback */
 	struct netns_core	core;
 	struct netns_mib	mib;
@@ -321,6 +323,10 @@ struct pernet_operations {
 	 * have to keep in mind all other pernet_operations and
 	 * to introduce a locking, if they share common resources.
 	 *
+	 * The only time they are called with exclusive lock is
+	 * from register_pernet_subsys(), unregister_pernet_subsys()
+	 * register_pernet_device() and unregister_pernet_device().
+	 *
 	 * Exit methods using blocking RCU primitives, such as
 	 * synchronize_rcu(), should be implemented via exit_batch.
 	 * Then, destruction of a group of net requires single
@@ -333,12 +339,6 @@ struct pernet_operations {
 	void (*exit_batch)(struct list_head *net_exit_list);
 	unsigned int *id;
 	size_t size;
-	/*
-	 * Indicates above methods are allowed to be executed in parallel
-	 * with methods of any other pernet_operations, i.e. they are not
-	 * need write locked net_sem.
-	 */
-	bool async;
 };
 
 /*

kernel/audit.c

@@ -1526,7 +1526,6 @@ static struct pernet_operations audit_net_ops __net_initdata = {
 	.exit = audit_net_exit,
 	.id = &audit_net_id,
 	.size = sizeof(struct audit_net),
-	.async = true,
 };
 
 /* Initialize audit support at boot time. */

lib/kobject_uevent.c

@@ -724,7 +724,6 @@ static void uevent_net_exit(struct net *net)
 static struct pernet_operations uevent_net_ops = {
 	.init	= uevent_net_init,
 	.exit	= uevent_net_exit,
-	.async  = true,
 };
 
 static int __init kobject_uevent_init(void)

net/8021q/vlan.c

@@ -729,7 +729,6 @@ static struct pernet_operations vlan_net_ops = {
 	.exit = vlan_exit_net,
 	.id   = &vlan_net_id,
 	.size = sizeof(struct vlan_net),
-	.async = true,
 };
 
 static int __init vlan_proto_init(void)

net/bridge/br.c

@@ -188,7 +188,6 @@ static void __net_exit br_net_exit(struct net *net)
 
 static struct pernet_operations br_net_ops = {
 	.exit	= br_net_exit,
-	.async	= true,
 };
 
 static const struct stp_proto br_stp_proto = {

net/bridge/br_netfilter_hooks.c

@@ -969,7 +969,6 @@ static struct pernet_operations brnf_net_ops __read_mostly = {
 	.exit = brnf_exit_net,
 	.id   = &brnf_net_id,
 	.size = sizeof(struct brnf_net),
-	.async = true,
 };
 
 static struct notifier_block brnf_notifier __read_mostly = {

net/bridge/netfilter/ebtable_broute.c

@@ -77,7 +77,6 @@ static void __net_exit broute_net_exit(struct net *net)
 static struct pernet_operations broute_net_ops = {
 	.init = broute_net_init,
 	.exit = broute_net_exit,
-	.async = true,
 };
 
 static int __init ebtable_broute_init(void)

net/bridge/netfilter/ebtable_filter.c

@@ -105,7 +105,6 @@ static void __net_exit frame_filter_net_exit(struct net *net)
 static struct pernet_operations frame_filter_net_ops = {
 	.init = frame_filter_net_init,
 	.exit = frame_filter_net_exit,
-	.async = true,
 };
 
 static int __init ebtable_filter_init(void)

net/bridge/netfilter/ebtable_nat.c

@@ -105,7 +105,6 @@ static void __net_exit frame_nat_net_exit(struct net *net)
 static struct pernet_operations frame_nat_net_ops = {
 	.init = frame_nat_net_init,
 	.exit = frame_nat_net_exit,
-	.async = true,
 };
 
 static int __init ebtable_nat_init(void)

net/bridge/netfilter/nf_log_bridge.c

@@ -48,7 +48,6 @@ static void __net_exit nf_log_bridge_net_exit(struct net *net)
 static struct pernet_operations nf_log_bridge_net_ops = {
 	.init = nf_log_bridge_net_init,
 	.exit = nf_log_bridge_net_exit,
-	.async = true,
 };
 
 static int __init nf_log_bridge_init(void)

net/caif/caif_dev.c

@@ -544,7 +544,6 @@ static struct pernet_operations caif_net_ops = {
 	.exit = caif_exit_net,
 	.id   = &caif_net_id,
 	.size = sizeof(struct caif_net),
-	.async = true,
 };
 
 /* Initialize Caif devices list */

net/can/af_can.c

@@ -954,7 +954,6 @@ static struct notifier_block can_netdev_notifier __read_mostly = {
 static struct pernet_operations can_pernet_ops __read_mostly = {
 	.init = can_pernet_init,
 	.exit = can_pernet_exit,
-	.async = true,
 };
 
 static __init int can_init(void)

net/can/bcm.c

@@ -1717,7 +1717,6 @@ static void canbcm_pernet_exit(struct net *net)
 static struct pernet_operations canbcm_pernet_ops __read_mostly = {
 	.init = canbcm_pernet_init,
 	.exit = canbcm_pernet_exit,
-	.async = true,
 };
 
 static int __init bcm_module_init(void)

net/can/gw.c

@@ -1010,7 +1010,6 @@ static void __net_exit cangw_pernet_exit(struct net *net)
 static struct pernet_operations cangw_pernet_ops = {
 	.init = cangw_pernet_init,
 	.exit = cangw_pernet_exit,
-	.async = true,
 };
 
 static __init int cgw_module_init(void)

net/core/dev.c

@@ -8883,7 +8883,6 @@ static void __net_exit netdev_exit(struct net *net)
 static struct pernet_operations __net_initdata netdev_net_ops = {
 	.init = netdev_init,
 	.exit = netdev_exit,
-	.async = true,
 };
 
 static void __net_exit default_device_exit(struct net *net)
@@ -8984,7 +8983,6 @@ static void __net_exit default_device_exit_batch(struct list_head *net_list)
 static struct pernet_operations __net_initdata default_device_ops = {
 	.exit = default_device_exit,
 	.exit_batch = default_device_exit_batch,
-	.async = true,
 };
 
 /*

net/core/fib_notifier.c

@@ -171,7 +171,6 @@ static void __net_exit fib_notifier_net_exit(struct net *net)
 static struct pernet_operations fib_notifier_net_ops = {
 	.init = fib_notifier_net_init,
 	.exit = fib_notifier_net_exit,
-	.async = true,
 };
 
 static int __init fib_notifier_init(void)

net/core/fib_rules.c

@@ -1130,7 +1130,6 @@ static void __net_exit fib_rules_net_exit(struct net *net)
 static struct pernet_operations fib_rules_net_ops = {
 	.init = fib_rules_net_init,
 	.exit = fib_rules_net_exit,
-	.async = true,
 };
 
 static int __init fib_rules_init(void)

net/core/net-procfs.c

@@ -349,7 +349,6 @@ static void __net_exit dev_proc_net_exit(struct net *net)
 static struct pernet_operations __net_initdata dev_proc_ops = {
 	.init = dev_proc_net_init,
 	.exit = dev_proc_net_exit,
-	.async = true,
 };
 
 static int dev_mc_seq_show(struct seq_file *seq, void *v)
@@ -406,7 +405,6 @@ static void __net_exit dev_mc_net_exit(struct net *net)
 static struct pernet_operations __net_initdata dev_mc_net_ops = {
 	.init = dev_mc_net_init,
 	.exit = dev_mc_net_exit,
-	.async = true,
 };
 
 int __init dev_proc_init(void)