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>

15 files changed, 16 insertions, 16 deletions

diff --git a/net/sched/act_bpf.c b/net/sched/act_bpf.c
index 9ff06cfbcdec..1aa4ecf41baf 100644
--- a/net/sched/act_bpf.c
+++ b/net/sched/act_bpf.c
@@ -33,7 +33,7 @@ struct tcf_bpf_cfg {
 	bool is_ebpf;
 };
 
-static int bpf_net_id;
+static unsigned int bpf_net_id;
 static struct tc_action_ops act_bpf_ops;
 
 static int tcf_bpf(struct sk_buff *skb, const struct tc_action *act,
diff --git a/net/sched/act_connmark.c b/net/sched/act_connmark.c
index eae07a2e774d..ab8062909962 100644
--- a/net/sched/act_connmark.c
+++ b/net/sched/act_connmark.c
@@ -30,7 +30,7 @@
 
 #define CONNMARK_TAB_MASK     3
 
-static int connmark_net_id;
+static unsigned int connmark_net_id;
 static struct tc_action_ops act_connmark_ops;
 
 static int tcf_connmark(struct sk_buff *skb, const struct tc_action *a,
diff --git a/net/sched/act_csum.c b/net/sched/act_csum.c
index e0defcef376d..a0edd80a44db 100644
--- a/net/sched/act_csum.c
+++ b/net/sched/act_csum.c
@@ -42,7 +42,7 @@ static const struct nla_policy csum_policy[TCA_CSUM_MAX + 1] = {
 	[TCA_CSUM_PARMS] = { .len = sizeof(struct tc_csum), },
 };
 
-static int csum_net_id;
+static unsigned int csum_net_id;
 static struct tc_action_ops act_csum_ops;
 
 static int tcf_csum_init(struct net *net, struct nlattr *nla,
diff --git a/net/sched/act_gact.c b/net/sched/act_gact.c
index e0aa30f83c6c..e6c874a2b283 100644
--- a/net/sched/act_gact.c
+++ b/net/sched/act_gact.c
@@ -25,7 +25,7 @@
 
 #define GACT_TAB_MASK	15
 
-static int gact_net_id;
+static unsigned int gact_net_id;
 static struct tc_action_ops act_gact_ops;
 
 #ifdef CONFIG_GACT_PROB
diff --git a/net/sched/act_ife.c b/net/sched/act_ife.c
index 95c463cbb9a6..80b848d3f096 100644
--- a/net/sched/act_ife.c
+++ b/net/sched/act_ife.c
@@ -35,7 +35,7 @@
 
 #define IFE_TAB_MASK 15
 
-static int ife_net_id;
+static unsigned int ife_net_id;
 static int max_metacnt = IFE_META_MAX + 1;
 static struct tc_action_ops act_ife_ops;
 
diff --git a/net/sched/act_ipt.c b/net/sched/act_ipt.c
index ce7ea6c1c50d..992ef8d624f1 100644
--- a/net/sched/act_ipt.c
+++ b/net/sched/act_ipt.c
@@ -30,10 +30,10 @@
 
 #define IPT_TAB_MASK     15
 
-static int ipt_net_id;
+static unsigned int ipt_net_id;
 static struct tc_action_ops act_ipt_ops;
 
-static int xt_net_id;
+static unsigned int xt_net_id;
 static struct tc_action_ops act_xt_ops;
 
 static int ipt_init_target(struct xt_entry_target *t, char *table,
diff --git a/net/sched/act_mirred.c b/net/sched/act_mirred.c
index 6073a1132725..b2d417b8f46c 100644
--- a/net/sched/act_mirred.c
+++ b/net/sched/act_mirred.c
@@ -70,7 +70,7 @@ static const struct nla_policy mirred_policy[TCA_MIRRED_MAX + 1] = {
 	[TCA_MIRRED_PARMS]	= { .len = sizeof(struct tc_mirred) },
 };
 
-static int mirred_net_id;
+static unsigned int mirred_net_id;
 static struct tc_action_ops act_mirred_ops;
 
 static bool dev_is_mac_header_xmit(const struct net_device *dev)
diff --git a/net/sched/act_nat.c b/net/sched/act_nat.c
index 8e8b0cc30704..9b6aec665495 100644
--- a/net/sched/act_nat.c
+++ b/net/sched/act_nat.c
@@ -31,7 +31,7 @@
 
 #define NAT_TAB_MASK	15
 
-static int nat_net_id;
+static unsigned int nat_net_id;
 static struct tc_action_ops act_nat_ops;
 
 static const struct nla_policy nat_policy[TCA_NAT_MAX + 1] = {
diff --git a/net/sched/act_pedit.c b/net/sched/act_pedit.c
index b54d56d4959b..eda322045e75 100644
--- a/net/sched/act_pedit.c
+++ b/net/sched/act_pedit.c
@@ -25,7 +25,7 @@
 
 #define PEDIT_TAB_MASK	15
 
-static int pedit_net_id;
+static unsigned int pedit_net_id;
 static struct tc_action_ops act_pedit_ops;
 
 static const struct nla_policy pedit_policy[TCA_PEDIT_MAX + 1] = {
diff --git a/net/sched/act_police.c b/net/sched/act_police.c
index d1bd248fe146..c990b73a6c85 100644
--- a/net/sched/act_police.c
+++ b/net/sched/act_police.c
@@ -55,7 +55,7 @@ struct tc_police_compat {
 
 /* Each policer is serialized by its individual spinlock */
 
-static int police_net_id;
+static unsigned int police_net_id;
 static struct tc_action_ops act_police_ops;
 
 static int tcf_act_police_walker(struct net *net, struct sk_buff *skb,
diff --git a/net/sched/act_simple.c b/net/sched/act_simple.c
index 289af6f9bb3b..823a73ad0c60 100644
--- a/net/sched/act_simple.c
+++ b/net/sched/act_simple.c
@@ -26,7 +26,7 @@
 
 #define SIMP_TAB_MASK     7
 
-static int simp_net_id;
+static unsigned int simp_net_id;
 static struct tc_action_ops act_simp_ops;
 
 #define SIMP_MAX_DATA	32
diff --git a/net/sched/act_skbedit.c b/net/sched/act_skbedit.c
index 024f3a3afeff..06ccae3c12ee 100644
--- a/net/sched/act_skbedit.c
+++ b/net/sched/act_skbedit.c
@@ -29,7 +29,7 @@
 
 #define SKBEDIT_TAB_MASK     15
 
-static int skbedit_net_id;
+static unsigned int skbedit_net_id;
 static struct tc_action_ops act_skbedit_ops;
 
 static int tcf_skbedit(struct sk_buff *skb, const struct tc_action *a,
diff --git a/net/sched/act_skbmod.c b/net/sched/act_skbmod.c
index e7d96381c908..3b7074e23024 100644
--- a/net/sched/act_skbmod.c
+++ b/net/sched/act_skbmod.c
@@ -22,7 +22,7 @@
 
 #define SKBMOD_TAB_MASK     15
 
-static int skbmod_net_id;
+static unsigned int skbmod_net_id;
 static struct tc_action_ops act_skbmod_ops;
 
 #define MAX_EDIT_LEN ETH_HLEN
diff --git a/net/sched/act_tunnel_key.c b/net/sched/act_tunnel_key.c
index edc720f11687..7af712526f01 100644
--- a/net/sched/act_tunnel_key.c
+++ b/net/sched/act_tunnel_key.c
@@ -22,7 +22,7 @@
 
 #define TUNNEL_KEY_TAB_MASK     15
 
-static int tunnel_key_net_id;
+static unsigned int tunnel_key_net_id;
 static struct tc_action_ops act_tunnel_key_ops;
 
 static int tunnel_key_act(struct sk_buff *skb, const struct tc_action *a,
diff --git a/net/sched/act_vlan.c b/net/sched/act_vlan.c
index b57fcbcefea1..19e0dba305ce 100644
--- a/net/sched/act_vlan.c
+++ b/net/sched/act_vlan.c
@@ -21,7 +21,7 @@
 
 #define VLAN_TAB_MASK     15
 
-static int vlan_net_id;
+static unsigned int vlan_net_id;
 static struct tc_action_ops act_vlan_ops;
 
 static int tcf_vlan(struct sk_buff *skb, const struct tc_action *a,