netns: make struct pernet_operations::id unsigned int

Make struct pernet_operations::id unsigned.

There are 2 reasons to do so:

1)
This field is really an index into an zero based array and
thus is unsigned entity. Using negative value is out-of-bound
access by definition.

2)
On x86_64 unsigned 32-bit data which are mixed with pointers
via array indexing or offsets added or subtracted to pointers
are preffered to signed 32-bit data.

"int" being used as an array index needs to be sign-extended
to 64-bit before being used.

	void f(long *p, int i)
	{
		g(p[i]);
	}

  roughly translates to

	movsx	rsi, esi
	mov	rdi, [rsi+...]
	call 	g

MOVSX is 3 byte instruction which isn't necessary if the variable is
unsigned because x86_64 is zero extending by default.

Now, there is net_generic() function which, you guessed it right, uses
"int" as an array index:

	static inline void *net_generic(const struct net *net, int id)
	{
		...
		ptr = ng->ptr[id - 1];
		...
	}

And this function is used a lot, so those sign extensions add up.

Patch snipes ~1730 bytes on allyesconfig kernel (without all junk
messing with code generation):

	add/remove: 0/0 grow/shrink: 70/598 up/down: 396/-2126 (-1730)

Unfortunately some functions actually grow bigger.
This is a semmingly random artefact of code generation with register
allocator being used differently. gcc decides that some variable
needs to live in new r8+ registers and every access now requires REX
prefix. Or it is shifted into r12, so [r12+0] addressing mode has to be
used which is longer than [r8]

However, overall balance is in negative direction:

	add/remove: 0/0 grow/shrink: 70/598 up/down: 396/-2126 (-1730)
	function                                     old     new   delta
	nfsd4_lock                                  3886    3959     +73
	tipc_link_build_proto_msg                   1096    1140     +44
	mac80211_hwsim_new_radio                    2776    2808     +32
	tipc_mon_rcv                                1032    1058     +26
	svcauth_gss_legacy_init                     1413    1429     +16
	tipc_bcbase_select_primary                   379     392     +13
	nfsd4_exchange_id                           1247    1260     +13
	nfsd4_setclientid_confirm                    782     793     +11
		...
	put_client_renew_locked                      494     480     -14
	ip_set_sockfn_get                            730     716     -14
	geneve_sock_add                              829     813     -16
	nfsd4_sequence_done                          721     703     -18
	nlmclnt_lookup_host                          708     686     -22
	nfsd4_lockt                                 1085    1063     -22
	nfs_get_client                              1077    1050     -27
	tcf_bpf_init                                1106    1076     -30
	nfsd4_encode_fattr                          5997    5930     -67
	Total: Before=154856051, After=154854321, chg -0.00%

Signed-off-by: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

6 files changed, 8 insertions, 8 deletions

diff --git a/include/net/bonding.h b/include/net/bonding.h
index f32f7ef8a23a..3c857778a6ca 100644
--- a/include/net/bonding.h
+++ b/include/net/bonding.h
@@ -681,7 +681,7 @@ static inline int bond_get_targets_ip(__be32 *targets, __be32 ip)
 }
 
 /* exported from bond_main.c */
-extern int bond_net_id;
+extern unsigned int bond_net_id;
 extern const struct bond_parm_tbl bond_lacp_tbl[];
 extern const struct bond_parm_tbl xmit_hashtype_tbl[];
 extern const struct bond_parm_tbl arp_validate_tbl[];
diff --git a/include/net/ip_tunnels.h b/include/net/ip_tunnels.h
index 59557c07904b..e893fe43dd13 100644
--- a/include/net/ip_tunnels.h
+++ b/include/net/ip_tunnels.h
@@ -129,7 +129,7 @@ struct ip_tunnel {
 #endif
 	struct ip_tunnel_prl_entry __rcu *prl;	/* potential router list */
 	unsigned int		prl_count;	/* # of entries in PRL */
-	int			ip_tnl_net_id;
+	unsigned int		ip_tnl_net_id;
 	struct gro_cells	gro_cells;
 	bool			collect_md;
 	bool			ignore_df;
@@ -248,7 +248,7 @@ void ip_tunnel_uninit(struct net_device *dev);
 void  ip_tunnel_dellink(struct net_device *dev, struct list_head *head);
 struct net *ip_tunnel_get_link_net(const struct net_device *dev);
 int ip_tunnel_get_iflink(const struct net_device *dev);
-int ip_tunnel_init_net(struct net *net, int ip_tnl_net_id,
+int ip_tunnel_init_net(struct net *net, unsigned int ip_tnl_net_id,
 		       struct rtnl_link_ops *ops, char *devname);
 
 void ip_tunnel_delete_net(struct ip_tunnel_net *itn, struct rtnl_link_ops *ops);
@@ -275,7 +275,7 @@ int ip_tunnel_changelink(struct net_device *dev, struct nlattr *tb[],
 			 struct ip_tunnel_parm *p);
 int ip_tunnel_newlink(struct net_device *dev, struct nlattr *tb[],
 		      struct ip_tunnel_parm *p);
-void ip_tunnel_setup(struct net_device *dev, int net_id);
+void ip_tunnel_setup(struct net_device *dev, unsigned int net_id);
 
 struct ip_tunnel_encap_ops {
 	size_t (*encap_hlen)(struct ip_tunnel_encap *e);
diff --git a/include/net/net_namespace.h b/include/net/net_namespace.h
index fc4f757107df..d7149e93a60a 100644
--- a/include/net/net_namespace.h
+++ b/include/net/net_namespace.h
@@ -291,7 +291,7 @@ struct pernet_operations {
 	int (*init)(struct net *net);
 	void (*exit)(struct net *net);
 	void (*exit_batch)(struct list_head *net_exit_list);
-	int *id;
+	unsigned int *id;
 	size_t size;
 };
 
diff --git a/include/net/netfilter/nf_conntrack_l4proto.h b/include/net/netfilter/nf_conntrack_l4proto.h
index 2152b70626d5..e7b836590f0b 100644
--- a/include/net/netfilter/nf_conntrack_l4proto.h
+++ b/include/net/netfilter/nf_conntrack_l4proto.h
@@ -98,7 +98,7 @@ struct nf_conntrack_l4proto {
 		const struct nla_policy *nla_policy;
 	} ctnl_timeout;
 #endif
-	int	*net_id;
+	unsigned int	*net_id;
 	/* Init l4proto pernet data */
 	int (*init_net)(struct net *net, u_int16_t proto);
 
diff --git a/include/net/netfilter/nf_conntrack_synproxy.h b/include/net/netfilter/nf_conntrack_synproxy.h
index e6937318546c..b0ca402c1f72 100644
--- a/include/net/netfilter/nf_conntrack_synproxy.h
+++ b/include/net/netfilter/nf_conntrack_synproxy.h
@@ -54,7 +54,7 @@ struct synproxy_net {
 	struct synproxy_stats __percpu	*stats;
 };
 
-extern int synproxy_net_id;
+extern unsigned int synproxy_net_id;
 static inline struct synproxy_net *synproxy_pernet(struct net *net)
 {
 	return net_generic(net, synproxy_net_id);
diff --git a/include/net/netns/generic.h b/include/net/netns/generic.h
index 70e158551704..d315786bcfd7 100644
--- a/include/net/netns/generic.h
+++ b/include/net/netns/generic.h
@@ -31,7 +31,7 @@ struct net_generic {
 	void *ptr[0];
 };
 
-static inline void *net_generic(const struct net *net, int id)
+static inline void *net_generic(const struct net *net, unsigned int id)
 {
 	struct net_generic *ng;
 	void *ptr;