![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>
224 lines
6.5 KiB
C
224 lines
6.5 KiB
C
/*
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* Copyright (c) 2007-2014 Nicira, Inc.
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of version 2 of the GNU General Public
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* License as published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
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* 02110-1301, USA
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*/
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#ifndef DATAPATH_H
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#define DATAPATH_H 1
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#include <asm/page.h>
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#include <linux/kernel.h>
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#include <linux/mutex.h>
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#include <linux/netdevice.h>
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#include <linux/skbuff.h>
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#include <linux/u64_stats_sync.h>
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#include <net/ip_tunnels.h>
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#include "conntrack.h"
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#include "flow.h"
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#include "flow_table.h"
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#define DP_MAX_PORTS USHRT_MAX
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#define DP_VPORT_HASH_BUCKETS 1024
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#define SAMPLE_ACTION_DEPTH 3
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/**
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* struct dp_stats_percpu - per-cpu packet processing statistics for a given
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* datapath.
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* @n_hit: Number of received packets for which a matching flow was found in
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* the flow table.
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* @n_miss: Number of received packets that had no matching flow in the flow
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* table. The sum of @n_hit and @n_miss is the number of packets that have
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* been received by the datapath.
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* @n_lost: Number of received packets that had no matching flow in the flow
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* table that could not be sent to userspace (normally due to an overflow in
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* one of the datapath's queues).
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* @n_mask_hit: Number of masks looked up for flow match.
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* @n_mask_hit / (@n_hit + @n_missed) will be the average masks looked
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* up per packet.
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*/
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struct dp_stats_percpu {
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u64 n_hit;
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u64 n_missed;
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u64 n_lost;
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u64 n_mask_hit;
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struct u64_stats_sync syncp;
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};
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/**
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* struct datapath - datapath for flow-based packet switching
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* @rcu: RCU callback head for deferred destruction.
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* @list_node: Element in global 'dps' list.
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* @table: flow table.
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* @ports: Hash table for ports. %OVSP_LOCAL port always exists. Protected by
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* ovs_mutex and RCU.
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* @stats_percpu: Per-CPU datapath statistics.
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* @net: Reference to net namespace.
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* @max_headroom: the maximum headroom of all vports in this datapath; it will
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* be used by all the internal vports in this dp.
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*
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* Context: See the comment on locking at the top of datapath.c for additional
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* locking information.
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*/
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struct datapath {
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struct rcu_head rcu;
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struct list_head list_node;
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/* Flow table. */
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struct flow_table table;
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/* Switch ports. */
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struct hlist_head *ports;
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/* Stats. */
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struct dp_stats_percpu __percpu *stats_percpu;
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/* Network namespace ref. */
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possible_net_t net;
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u32 user_features;
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u32 max_headroom;
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};
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/**
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* struct ovs_skb_cb - OVS data in skb CB
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* @input_vport: The original vport packet came in on. This value is cached
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* when a packet is received by OVS.
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* @mru: The maximum received fragement size; 0 if the packet is not
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* @cutlen: The number of bytes from the packet end to be removed.
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* fragmented.
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*/
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struct ovs_skb_cb {
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struct vport *input_vport;
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u16 mru;
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u32 cutlen;
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};
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#define OVS_CB(skb) ((struct ovs_skb_cb *)(skb)->cb)
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/**
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* struct dp_upcall - metadata to include with a packet to send to userspace
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* @cmd: One of %OVS_PACKET_CMD_*.
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* @userdata: If nonnull, its variable-length value is passed to userspace as
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* %OVS_PACKET_ATTR_USERDATA.
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* @portid: Netlink portid to which packet should be sent. If @portid is 0
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* then no packet is sent and the packet is accounted in the datapath's @n_lost
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* counter.
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* @egress_tun_info: If nonnull, becomes %OVS_PACKET_ATTR_EGRESS_TUN_KEY.
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* @mru: If not zero, Maximum received IP fragment size.
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*/
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struct dp_upcall_info {
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struct ip_tunnel_info *egress_tun_info;
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const struct nlattr *userdata;
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const struct nlattr *actions;
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int actions_len;
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u32 portid;
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u8 cmd;
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u16 mru;
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};
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/**
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* struct ovs_net - Per net-namespace data for ovs.
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* @dps: List of datapaths to enable dumping them all out.
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* Protected by genl_mutex.
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*/
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struct ovs_net {
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struct list_head dps;
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struct work_struct dp_notify_work;
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/* Module reference for configuring conntrack. */
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bool xt_label;
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};
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extern unsigned int ovs_net_id;
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void ovs_lock(void);
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void ovs_unlock(void);
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#ifdef CONFIG_LOCKDEP
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int lockdep_ovsl_is_held(void);
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#else
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#define lockdep_ovsl_is_held() 1
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#endif
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#define ASSERT_OVSL() WARN_ON(!lockdep_ovsl_is_held())
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#define ovsl_dereference(p) \
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rcu_dereference_protected(p, lockdep_ovsl_is_held())
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#define rcu_dereference_ovsl(p) \
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rcu_dereference_check(p, lockdep_ovsl_is_held())
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static inline struct net *ovs_dp_get_net(const struct datapath *dp)
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{
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return read_pnet(&dp->net);
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}
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static inline void ovs_dp_set_net(struct datapath *dp, struct net *net)
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{
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write_pnet(&dp->net, net);
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}
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struct vport *ovs_lookup_vport(const struct datapath *dp, u16 port_no);
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static inline struct vport *ovs_vport_rcu(const struct datapath *dp, int port_no)
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{
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WARN_ON_ONCE(!rcu_read_lock_held());
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return ovs_lookup_vport(dp, port_no);
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}
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static inline struct vport *ovs_vport_ovsl_rcu(const struct datapath *dp, int port_no)
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{
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WARN_ON_ONCE(!rcu_read_lock_held() && !lockdep_ovsl_is_held());
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return ovs_lookup_vport(dp, port_no);
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}
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static inline struct vport *ovs_vport_ovsl(const struct datapath *dp, int port_no)
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{
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ASSERT_OVSL();
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return ovs_lookup_vport(dp, port_no);
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}
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extern struct notifier_block ovs_dp_device_notifier;
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extern struct genl_family dp_vport_genl_family;
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void ovs_dp_process_packet(struct sk_buff *skb, struct sw_flow_key *key);
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void ovs_dp_detach_port(struct vport *);
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int ovs_dp_upcall(struct datapath *, struct sk_buff *,
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const struct sw_flow_key *, const struct dp_upcall_info *,
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uint32_t cutlen);
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const char *ovs_dp_name(const struct datapath *dp);
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struct sk_buff *ovs_vport_cmd_build_info(struct vport *, u32 pid, u32 seq,
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u8 cmd);
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int ovs_execute_actions(struct datapath *dp, struct sk_buff *skb,
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const struct sw_flow_actions *, struct sw_flow_key *);
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void ovs_dp_notify_wq(struct work_struct *work);
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int action_fifos_init(void);
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void action_fifos_exit(void);
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/* 'KEY' must not have any bits set outside of the 'MASK' */
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#define OVS_MASKED(OLD, KEY, MASK) ((KEY) | ((OLD) & ~(MASK)))
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#define OVS_SET_MASKED(OLD, KEY, MASK) ((OLD) = OVS_MASKED(OLD, KEY, MASK))
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#define OVS_NLERR(logging_allowed, fmt, ...) \
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do { \
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if (logging_allowed && net_ratelimit()) \
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pr_info("netlink: " fmt "\n", ##__VA_ARGS__); \
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} while (0)
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#endif /* datapath.h */
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