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https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
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![Alexey Dobriyan](/assets/img/avatar_default.png)
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>
384 lines
9.2 KiB
C
384 lines
9.2 KiB
C
/*
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* Operations on the network namespace
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*/
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#ifndef __NET_NET_NAMESPACE_H
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#define __NET_NET_NAMESPACE_H
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#include <linux/atomic.h>
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#include <linux/workqueue.h>
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#include <linux/list.h>
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#include <linux/sysctl.h>
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#include <net/flow.h>
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#include <net/netns/core.h>
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#include <net/netns/mib.h>
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#include <net/netns/unix.h>
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#include <net/netns/packet.h>
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#include <net/netns/ipv4.h>
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#include <net/netns/ipv6.h>
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#include <net/netns/ieee802154_6lowpan.h>
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#include <net/netns/sctp.h>
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#include <net/netns/dccp.h>
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#include <net/netns/netfilter.h>
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#include <net/netns/x_tables.h>
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#if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
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#include <net/netns/conntrack.h>
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#endif
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#include <net/netns/nftables.h>
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#include <net/netns/xfrm.h>
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#include <net/netns/mpls.h>
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#include <linux/ns_common.h>
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#include <linux/idr.h>
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#include <linux/skbuff.h>
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struct user_namespace;
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struct proc_dir_entry;
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struct net_device;
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struct sock;
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struct ctl_table_header;
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struct net_generic;
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struct sock;
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struct netns_ipvs;
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#define NETDEV_HASHBITS 8
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#define NETDEV_HASHENTRIES (1 << NETDEV_HASHBITS)
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struct net {
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atomic_t passive; /* To decided when the network
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* namespace should be freed.
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*/
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atomic_t count; /* To decided when the network
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* namespace should be shut down.
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*/
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spinlock_t rules_mod_lock;
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atomic64_t cookie_gen;
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struct list_head list; /* list of network namespaces */
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struct list_head cleanup_list; /* namespaces on death row */
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struct list_head exit_list; /* Use only net_mutex */
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struct user_namespace *user_ns; /* Owning user namespace */
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struct ucounts *ucounts;
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spinlock_t nsid_lock;
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struct idr netns_ids;
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struct ns_common ns;
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struct proc_dir_entry *proc_net;
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struct proc_dir_entry *proc_net_stat;
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#ifdef CONFIG_SYSCTL
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struct ctl_table_set sysctls;
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#endif
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struct sock *rtnl; /* rtnetlink socket */
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struct sock *genl_sock;
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struct list_head dev_base_head;
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struct hlist_head *dev_name_head;
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struct hlist_head *dev_index_head;
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unsigned int dev_base_seq; /* protected by rtnl_mutex */
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int ifindex;
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unsigned int dev_unreg_count;
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/* core fib_rules */
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struct list_head rules_ops;
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struct net_device *loopback_dev; /* The loopback */
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struct netns_core core;
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struct netns_mib mib;
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struct netns_packet packet;
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struct netns_unix unx;
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struct netns_ipv4 ipv4;
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#if IS_ENABLED(CONFIG_IPV6)
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struct netns_ipv6 ipv6;
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#endif
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#if IS_ENABLED(CONFIG_IEEE802154_6LOWPAN)
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struct netns_ieee802154_lowpan ieee802154_lowpan;
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#endif
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#if defined(CONFIG_IP_SCTP) || defined(CONFIG_IP_SCTP_MODULE)
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struct netns_sctp sctp;
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#endif
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#if defined(CONFIG_IP_DCCP) || defined(CONFIG_IP_DCCP_MODULE)
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struct netns_dccp dccp;
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#endif
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#ifdef CONFIG_NETFILTER
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struct netns_nf nf;
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struct netns_xt xt;
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#if defined(CONFIG_NF_CONNTRACK) || defined(CONFIG_NF_CONNTRACK_MODULE)
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struct netns_ct ct;
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#endif
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#if defined(CONFIG_NF_TABLES) || defined(CONFIG_NF_TABLES_MODULE)
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struct netns_nftables nft;
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#endif
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#if IS_ENABLED(CONFIG_NF_DEFRAG_IPV6)
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struct netns_nf_frag nf_frag;
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#endif
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struct sock *nfnl;
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struct sock *nfnl_stash;
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#if IS_ENABLED(CONFIG_NETFILTER_NETLINK_ACCT)
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struct list_head nfnl_acct_list;
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#endif
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#if IS_ENABLED(CONFIG_NF_CT_NETLINK_TIMEOUT)
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struct list_head nfct_timeout_list;
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#endif
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#endif
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#ifdef CONFIG_WEXT_CORE
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struct sk_buff_head wext_nlevents;
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#endif
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struct net_generic __rcu *gen;
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/* Note : following structs are cache line aligned */
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#ifdef CONFIG_XFRM
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struct netns_xfrm xfrm;
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#endif
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#if IS_ENABLED(CONFIG_IP_VS)
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struct netns_ipvs *ipvs;
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#endif
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#if IS_ENABLED(CONFIG_MPLS)
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struct netns_mpls mpls;
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#endif
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struct sock *diag_nlsk;
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atomic_t fnhe_genid;
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};
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#include <linux/seq_file_net.h>
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/* Init's network namespace */
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extern struct net init_net;
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#ifdef CONFIG_NET_NS
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struct net *copy_net_ns(unsigned long flags, struct user_namespace *user_ns,
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struct net *old_net);
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#else /* CONFIG_NET_NS */
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#include <linux/sched.h>
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#include <linux/nsproxy.h>
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static inline struct net *copy_net_ns(unsigned long flags,
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struct user_namespace *user_ns, struct net *old_net)
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{
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if (flags & CLONE_NEWNET)
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return ERR_PTR(-EINVAL);
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return old_net;
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}
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#endif /* CONFIG_NET_NS */
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extern struct list_head net_namespace_list;
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struct net *get_net_ns_by_pid(pid_t pid);
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struct net *get_net_ns_by_fd(int pid);
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#ifdef CONFIG_SYSCTL
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void ipx_register_sysctl(void);
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void ipx_unregister_sysctl(void);
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#else
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#define ipx_register_sysctl()
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#define ipx_unregister_sysctl()
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#endif
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#ifdef CONFIG_NET_NS
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void __put_net(struct net *net);
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static inline struct net *get_net(struct net *net)
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{
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atomic_inc(&net->count);
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return net;
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}
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static inline struct net *maybe_get_net(struct net *net)
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{
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/* Used when we know struct net exists but we
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* aren't guaranteed a previous reference count
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* exists. If the reference count is zero this
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* function fails and returns NULL.
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*/
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if (!atomic_inc_not_zero(&net->count))
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net = NULL;
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return net;
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}
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static inline void put_net(struct net *net)
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{
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if (atomic_dec_and_test(&net->count))
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__put_net(net);
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}
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static inline
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int net_eq(const struct net *net1, const struct net *net2)
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{
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return net1 == net2;
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}
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void net_drop_ns(void *);
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#else
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static inline struct net *get_net(struct net *net)
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{
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return net;
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}
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static inline void put_net(struct net *net)
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{
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}
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static inline struct net *maybe_get_net(struct net *net)
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{
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return net;
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}
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static inline
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int net_eq(const struct net *net1, const struct net *net2)
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{
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return 1;
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}
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#define net_drop_ns NULL
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#endif
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typedef struct {
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#ifdef CONFIG_NET_NS
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struct net *net;
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#endif
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} possible_net_t;
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static inline void write_pnet(possible_net_t *pnet, struct net *net)
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{
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#ifdef CONFIG_NET_NS
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pnet->net = net;
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#endif
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}
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static inline struct net *read_pnet(const possible_net_t *pnet)
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{
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#ifdef CONFIG_NET_NS
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return pnet->net;
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#else
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return &init_net;
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#endif
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}
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#define for_each_net(VAR) \
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list_for_each_entry(VAR, &net_namespace_list, list)
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#define for_each_net_rcu(VAR) \
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list_for_each_entry_rcu(VAR, &net_namespace_list, list)
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#ifdef CONFIG_NET_NS
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#define __net_init
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#define __net_exit
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#define __net_initdata
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#define __net_initconst
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#else
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#define __net_init __init
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#define __net_exit __ref
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#define __net_initdata __initdata
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#define __net_initconst __initconst
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#endif
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int peernet2id_alloc(struct net *net, struct net *peer);
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int peernet2id(struct net *net, struct net *peer);
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bool peernet_has_id(struct net *net, struct net *peer);
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struct net *get_net_ns_by_id(struct net *net, int id);
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struct pernet_operations {
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struct list_head list;
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int (*init)(struct net *net);
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void (*exit)(struct net *net);
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void (*exit_batch)(struct list_head *net_exit_list);
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unsigned int *id;
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size_t size;
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};
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/*
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* Use these carefully. If you implement a network device and it
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* needs per network namespace operations use device pernet operations,
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* otherwise use pernet subsys operations.
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*
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* Network interfaces need to be removed from a dying netns _before_
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* subsys notifiers can be called, as most of the network code cleanup
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* (which is done from subsys notifiers) runs with the assumption that
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* dev_remove_pack has been called so no new packets will arrive during
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* and after the cleanup functions have been called. dev_remove_pack
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* is not per namespace so instead the guarantee of no more packets
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* arriving in a network namespace is provided by ensuring that all
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* network devices and all sockets have left the network namespace
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* before the cleanup methods are called.
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*
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* For the longest time the ipv4 icmp code was registered as a pernet
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* device which caused kernel oops, and panics during network
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* namespace cleanup. So please don't get this wrong.
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*/
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int register_pernet_subsys(struct pernet_operations *);
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void unregister_pernet_subsys(struct pernet_operations *);
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int register_pernet_device(struct pernet_operations *);
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void unregister_pernet_device(struct pernet_operations *);
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struct ctl_table;
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struct ctl_table_header;
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#ifdef CONFIG_SYSCTL
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int net_sysctl_init(void);
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struct ctl_table_header *register_net_sysctl(struct net *net, const char *path,
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struct ctl_table *table);
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void unregister_net_sysctl_table(struct ctl_table_header *header);
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#else
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static inline int net_sysctl_init(void) { return 0; }
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static inline struct ctl_table_header *register_net_sysctl(struct net *net,
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const char *path, struct ctl_table *table)
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{
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return NULL;
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}
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static inline void unregister_net_sysctl_table(struct ctl_table_header *header)
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{
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}
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#endif
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static inline int rt_genid_ipv4(struct net *net)
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{
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return atomic_read(&net->ipv4.rt_genid);
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}
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static inline void rt_genid_bump_ipv4(struct net *net)
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{
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atomic_inc(&net->ipv4.rt_genid);
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}
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extern void (*__fib6_flush_trees)(struct net *net);
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static inline void rt_genid_bump_ipv6(struct net *net)
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{
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if (__fib6_flush_trees)
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__fib6_flush_trees(net);
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}
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#if IS_ENABLED(CONFIG_IEEE802154_6LOWPAN)
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static inline struct netns_ieee802154_lowpan *
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net_ieee802154_lowpan(struct net *net)
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{
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return &net->ieee802154_lowpan;
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}
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#endif
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/* For callers who don't really care about whether it's IPv4 or IPv6 */
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static inline void rt_genid_bump_all(struct net *net)
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{
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rt_genid_bump_ipv4(net);
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rt_genid_bump_ipv6(net);
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}
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static inline int fnhe_genid(struct net *net)
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{
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return atomic_read(&net->fnhe_genid);
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}
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static inline void fnhe_genid_bump(struct net *net)
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{
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atomic_inc(&net->fnhe_genid);
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}
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#endif /* __NET_NET_NAMESPACE_H */
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