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c7d03a00b5
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>
173 lines
4.6 KiB
C
173 lines
4.6 KiB
C
/*
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* net/tipc/core.h: Include file for TIPC global declarations
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*
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* Copyright (c) 2005-2006, 2013 Ericsson AB
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* Copyright (c) 2005-2007, 2010-2013, Wind River Systems
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions are met:
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*
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 3. Neither the names of the copyright holders nor the names of its
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* contributors may be used to endorse or promote products derived from
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* this software without specific prior written permission.
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*
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* Alternatively, this software may be distributed under the terms of the
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* GNU General Public License ("GPL") version 2 as published by the Free
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* Software Foundation.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
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* AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
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* LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
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* CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
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* SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
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* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
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* ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*/
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#ifndef _TIPC_CORE_H
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#define _TIPC_CORE_H
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#include <linux/tipc.h>
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#include <linux/tipc_config.h>
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#include <linux/tipc_netlink.h>
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#include <linux/types.h>
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#include <linux/kernel.h>
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#include <linux/errno.h>
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#include <linux/mm.h>
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#include <linux/timer.h>
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#include <linux/string.h>
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#include <linux/uaccess.h>
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#include <linux/interrupt.h>
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#include <linux/atomic.h>
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#include <asm/hardirq.h>
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#include <linux/netdevice.h>
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#include <linux/in.h>
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#include <linux/list.h>
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#include <linux/slab.h>
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#include <linux/vmalloc.h>
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#include <linux/rtnetlink.h>
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#include <linux/etherdevice.h>
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#include <net/netns/generic.h>
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#include <linux/rhashtable.h>
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struct tipc_node;
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struct tipc_bearer;
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struct tipc_bc_base;
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struct tipc_link;
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struct tipc_name_table;
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struct tipc_server;
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struct tipc_monitor;
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#define TIPC_MOD_VER "2.0.0"
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#define NODE_HTABLE_SIZE 512
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#define MAX_BEARERS 3
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#define TIPC_DEF_MON_THRESHOLD 32
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extern unsigned int tipc_net_id __read_mostly;
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extern int sysctl_tipc_rmem[3] __read_mostly;
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extern int sysctl_tipc_named_timeout __read_mostly;
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struct tipc_net {
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u32 own_addr;
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int net_id;
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int random;
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/* Node table and node list */
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spinlock_t node_list_lock;
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struct hlist_head node_htable[NODE_HTABLE_SIZE];
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struct list_head node_list;
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u32 num_nodes;
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u32 num_links;
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/* Neighbor monitoring list */
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struct tipc_monitor *monitors[MAX_BEARERS];
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int mon_threshold;
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/* Bearer list */
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struct tipc_bearer __rcu *bearer_list[MAX_BEARERS + 1];
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/* Broadcast link */
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spinlock_t bclock;
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struct tipc_bc_base *bcbase;
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struct tipc_link *bcl;
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/* Socket hash table */
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struct rhashtable sk_rht;
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/* Name table */
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spinlock_t nametbl_lock;
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struct name_table *nametbl;
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/* Name dist queue */
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struct list_head dist_queue;
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/* Topology subscription server */
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struct tipc_server *topsrv;
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atomic_t subscription_count;
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};
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static inline struct tipc_net *tipc_net(struct net *net)
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{
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return net_generic(net, tipc_net_id);
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}
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static inline int tipc_netid(struct net *net)
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{
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return tipc_net(net)->net_id;
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}
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static inline struct list_head *tipc_nodes(struct net *net)
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{
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return &tipc_net(net)->node_list;
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}
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static inline unsigned int tipc_hashfn(u32 addr)
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{
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return addr & (NODE_HTABLE_SIZE - 1);
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}
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static inline u16 mod(u16 x)
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{
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return x & 0xffffu;
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}
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static inline int less_eq(u16 left, u16 right)
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{
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return mod(right - left) < 32768u;
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}
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static inline int more(u16 left, u16 right)
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{
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return !less_eq(left, right);
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}
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static inline int less(u16 left, u16 right)
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{
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return less_eq(left, right) && (mod(right) != mod(left));
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}
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static inline int in_range(u16 val, u16 min, u16 max)
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{
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return !less(val, min) && !more(val, max);
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}
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#ifdef CONFIG_SYSCTL
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int tipc_register_sysctl(void);
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void tipc_unregister_sysctl(void);
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#else
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#define tipc_register_sysctl() 0
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#define tipc_unregister_sysctl()
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#endif
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#endif
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