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>
diff --git a/include/net/bonding.h b/include/net/bonding.h
index f32f7ef..3c85777 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 59557c0..e893fe4 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 fc4f757..d7149e9 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 2152b70..e7b8365 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 e693731..b0ca402 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 70e1585..d315786 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;