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>

11 files changed, 11 insertions, 11 deletions

diff --git a/net/netfilter/ipset/ip_set_core.c b/net/netfilter/ipset/ip_set_core.c
index 23345d2d136a..c296f9b606d4 100644
--- a/net/netfilter/ipset/ip_set_core.c
+++ b/net/netfilter/ipset/ip_set_core.c
@@ -36,7 +36,7 @@ struct ip_set_net {
 	bool		is_destroyed;	/* all sets are destroyed */
 };
 
-static int ip_set_net_id __read_mostly;
+static unsigned int ip_set_net_id __read_mostly;
 
 static inline struct ip_set_net *ip_set_pernet(struct net *net)
 {
diff --git a/net/netfilter/ipvs/ip_vs_core.c b/net/netfilter/ipvs/ip_vs_core.c
index 2c1b498a7a27..db40050f8785 100644
--- a/net/netfilter/ipvs/ip_vs_core.c
+++ b/net/netfilter/ipvs/ip_vs_core.c
@@ -70,7 +70,7 @@ EXPORT_SYMBOL(ip_vs_get_debug_level);
 #endif
 EXPORT_SYMBOL(ip_vs_new_conn_out);
 
-static int ip_vs_net_id __read_mostly;
+static unsigned int ip_vs_net_id __read_mostly;
 /* netns cnt used for uniqueness */
 static atomic_t ipvs_netns_cnt = ATOMIC_INIT(0);
 
diff --git a/net/netfilter/nf_conntrack_proto_dccp.c b/net/netfilter/nf_conntrack_proto_dccp.c
index ac8976964975..073b047314dc 100644
--- a/net/netfilter/nf_conntrack_proto_dccp.c
+++ b/net/netfilter/nf_conntrack_proto_dccp.c
@@ -385,7 +385,7 @@ dccp_state_table[CT_DCCP_ROLE_MAX + 1][DCCP_PKT_SYNCACK + 1][CT_DCCP_MAX + 1] =
 };
 
 /* this module per-net specifics */
-static int dccp_net_id __read_mostly;
+static unsigned int dccp_net_id __read_mostly;
 struct dccp_net {
 	struct nf_proto_net pn;
 	int dccp_loose;
diff --git a/net/netfilter/nf_conntrack_proto_gre.c b/net/netfilter/nf_conntrack_proto_gre.c
index ff405c9183f1..87bb40a3feb5 100644
--- a/net/netfilter/nf_conntrack_proto_gre.c
+++ b/net/netfilter/nf_conntrack_proto_gre.c
@@ -53,7 +53,7 @@ static unsigned int gre_timeouts[GRE_CT_MAX] = {
 	[GRE_CT_REPLIED]	= 180*HZ,
 };
 
-static int proto_gre_net_id __read_mostly;
+static unsigned int proto_gre_net_id __read_mostly;
 struct netns_proto_gre {
 	struct nf_proto_net	nf;
 	rwlock_t		keymap_lock;
diff --git a/net/netfilter/nf_conntrack_proto_sctp.c b/net/netfilter/nf_conntrack_proto_sctp.c
index 17c0ade23fd8..d096c2d6b87b 100644
--- a/net/netfilter/nf_conntrack_proto_sctp.c
+++ b/net/netfilter/nf_conntrack_proto_sctp.c
@@ -144,7 +144,7 @@ static const u8 sctp_conntracks[2][11][SCTP_CONNTRACK_MAX] = {
 	}
 };
 
-static int sctp_net_id	__read_mostly;
+static unsigned int sctp_net_id	__read_mostly;
 struct sctp_net {
 	struct nf_proto_net pn;
 	unsigned int timeouts[SCTP_CONNTRACK_MAX];
diff --git a/net/netfilter/nf_conntrack_proto_udplite.c b/net/netfilter/nf_conntrack_proto_udplite.c
index 8cdb4b1bf933..7808604c70a2 100644
--- a/net/netfilter/nf_conntrack_proto_udplite.c
+++ b/net/netfilter/nf_conntrack_proto_udplite.c
@@ -35,7 +35,7 @@ static unsigned int udplite_timeouts[UDPLITE_CT_MAX] = {
 	[UDPLITE_CT_REPLIED]	= 180*HZ,
 };
 
-static int udplite_net_id __read_mostly;
+static unsigned int udplite_net_id __read_mostly;
 struct udplite_net {
 	struct nf_proto_net pn;
 	unsigned int timeouts[UDPLITE_CT_MAX];
diff --git a/net/netfilter/nf_synproxy_core.c b/net/netfilter/nf_synproxy_core.c
index c8a4a48bced9..7c6d1fbe38b9 100644
--- a/net/netfilter/nf_synproxy_core.c
+++ b/net/netfilter/nf_synproxy_core.c
@@ -24,7 +24,7 @@
 #include <net/netfilter/nf_conntrack_synproxy.h>
 #include <net/netfilter/nf_conntrack_zones.h>
 
-int synproxy_net_id;
+unsigned int synproxy_net_id;
 EXPORT_SYMBOL_GPL(synproxy_net_id);
 
 bool
diff --git a/net/netfilter/nfnetlink_log.c b/net/netfilter/nfnetlink_log.c
index 7435505037b7..763cb4d54e8d 100644
--- a/net/netfilter/nfnetlink_log.c
+++ b/net/netfilter/nfnetlink_log.c
@@ -80,7 +80,7 @@ struct nfulnl_instance {
 
 #define INSTANCE_BUCKETS	16
 
-static int nfnl_log_net_id __read_mostly;
+static unsigned int nfnl_log_net_id __read_mostly;
 
 struct nfnl_log_net {
 	spinlock_t instances_lock;
diff --git a/net/netfilter/nfnetlink_queue.c b/net/netfilter/nfnetlink_queue.c
index 1e33115b399f..be7627b80400 100644
--- a/net/netfilter/nfnetlink_queue.c
+++ b/net/netfilter/nfnetlink_queue.c
@@ -77,7 +77,7 @@ struct nfqnl_instance {
 
 typedef int (*nfqnl_cmpfn)(struct nf_queue_entry *, unsigned long);
 
-static int nfnl_queue_net_id __read_mostly;
+static unsigned int nfnl_queue_net_id __read_mostly;
 
 #define INSTANCE_BUCKETS	16
 struct nfnl_queue_net {
diff --git a/net/netfilter/xt_hashlimit.c b/net/netfilter/xt_hashlimit.c
index b89b688e9d01..10063408141d 100644
--- a/net/netfilter/xt_hashlimit.c
+++ b/net/netfilter/xt_hashlimit.c
@@ -49,7 +49,7 @@ struct hashlimit_net {
 	struct proc_dir_entry	*ip6t_hashlimit;
 };
 
-static int hashlimit_net_id;
+static unsigned int hashlimit_net_id;
 static inline struct hashlimit_net *hashlimit_pernet(struct net *net)
 {
 	return net_generic(net, hashlimit_net_id);
diff --git a/net/netfilter/xt_recent.c b/net/netfilter/xt_recent.c
index bf250000e084..1d89a4eaf841 100644
--- a/net/netfilter/xt_recent.c
+++ b/net/netfilter/xt_recent.c
@@ -95,7 +95,7 @@ struct recent_net {
 #endif
 };
 
-static int recent_net_id __read_mostly;
+static unsigned int recent_net_id __read_mostly;
 
 static inline struct recent_net *recent_pernet(struct net *net)
 {