mirror of
https://github.com/torvalds/linux
synced 2024-11-05 18:23:50 +00:00
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>
178 lines
4.5 KiB
C
178 lines
4.5 KiB
C
/*
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* net/tipc/core.c: TIPC module code
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*
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* Copyright (c) 2003-2006, 2013, Ericsson AB
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* Copyright (c) 2005-2006, 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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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
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#include "core.h"
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#include "name_table.h"
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#include "subscr.h"
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#include "bearer.h"
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#include "net.h"
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#include "socket.h"
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#include "bcast.h"
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#include <linux/module.h>
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/* configurable TIPC parameters */
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unsigned int tipc_net_id __read_mostly;
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int sysctl_tipc_rmem[3] __read_mostly; /* min/default/max */
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static int __net_init tipc_init_net(struct net *net)
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{
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struct tipc_net *tn = net_generic(net, tipc_net_id);
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int err;
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tn->net_id = 4711;
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tn->own_addr = 0;
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tn->mon_threshold = TIPC_DEF_MON_THRESHOLD;
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get_random_bytes(&tn->random, sizeof(int));
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INIT_LIST_HEAD(&tn->node_list);
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spin_lock_init(&tn->node_list_lock);
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err = tipc_sk_rht_init(net);
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if (err)
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goto out_sk_rht;
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err = tipc_nametbl_init(net);
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if (err)
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goto out_nametbl;
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INIT_LIST_HEAD(&tn->dist_queue);
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err = tipc_topsrv_start(net);
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if (err)
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goto out_subscr;
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err = tipc_bcast_init(net);
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if (err)
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goto out_bclink;
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return 0;
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out_bclink:
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tipc_bcast_stop(net);
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out_subscr:
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tipc_nametbl_stop(net);
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out_nametbl:
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tipc_sk_rht_destroy(net);
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out_sk_rht:
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return err;
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}
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static void __net_exit tipc_exit_net(struct net *net)
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{
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tipc_topsrv_stop(net);
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tipc_net_stop(net);
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tipc_bcast_stop(net);
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tipc_nametbl_stop(net);
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tipc_sk_rht_destroy(net);
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}
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static struct pernet_operations tipc_net_ops = {
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.init = tipc_init_net,
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.exit = tipc_exit_net,
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.id = &tipc_net_id,
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.size = sizeof(struct tipc_net),
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};
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static int __init tipc_init(void)
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{
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int err;
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pr_info("Activated (version " TIPC_MOD_VER ")\n");
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sysctl_tipc_rmem[0] = RCVBUF_MIN;
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sysctl_tipc_rmem[1] = RCVBUF_DEF;
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sysctl_tipc_rmem[2] = RCVBUF_MAX;
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err = tipc_netlink_start();
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if (err)
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goto out_netlink;
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err = tipc_netlink_compat_start();
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if (err)
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goto out_netlink_compat;
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err = tipc_socket_init();
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if (err)
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goto out_socket;
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err = tipc_register_sysctl();
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if (err)
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goto out_sysctl;
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err = register_pernet_subsys(&tipc_net_ops);
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if (err)
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goto out_pernet;
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err = tipc_bearer_setup();
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if (err)
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goto out_bearer;
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pr_info("Started in single node mode\n");
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return 0;
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out_bearer:
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unregister_pernet_subsys(&tipc_net_ops);
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out_pernet:
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tipc_unregister_sysctl();
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out_sysctl:
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tipc_socket_stop();
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out_socket:
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tipc_netlink_compat_stop();
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out_netlink_compat:
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tipc_netlink_stop();
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out_netlink:
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pr_err("Unable to start in single node mode\n");
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return err;
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}
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static void __exit tipc_exit(void)
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{
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tipc_bearer_cleanup();
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unregister_pernet_subsys(&tipc_net_ops);
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tipc_netlink_stop();
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tipc_netlink_compat_stop();
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tipc_socket_stop();
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tipc_unregister_sysctl();
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pr_info("Deactivated\n");
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}
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module_init(tipc_init);
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module_exit(tipc_exit);
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MODULE_DESCRIPTION("TIPC: Transparent Inter Process Communication");
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MODULE_LICENSE("Dual BSD/GPL");
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MODULE_VERSION(TIPC_MOD_VER);
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