linux/net/sunrpc/sunrpc_syms.c
Alexey Dobriyan c7d03a00b5 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>
2016-11-18 10:59:15 -05:00

137 lines
2.6 KiB
C

/*
* linux/net/sunrpc/sunrpc_syms.c
*
* Symbols exported by the sunrpc module.
*
* Copyright (C) 1997 Olaf Kirch <okir@monad.swb.de>
*/
#include <linux/module.h>
#include <linux/types.h>
#include <linux/uio.h>
#include <linux/unistd.h>
#include <linux/init.h>
#include <linux/sunrpc/sched.h>
#include <linux/sunrpc/clnt.h>
#include <linux/sunrpc/svc.h>
#include <linux/sunrpc/svcsock.h>
#include <linux/sunrpc/auth.h>
#include <linux/workqueue.h>
#include <linux/sunrpc/rpc_pipe_fs.h>
#include <linux/sunrpc/xprtsock.h>
#include "netns.h"
unsigned int sunrpc_net_id;
EXPORT_SYMBOL_GPL(sunrpc_net_id);
static __net_init int sunrpc_init_net(struct net *net)
{
int err;
struct sunrpc_net *sn = net_generic(net, sunrpc_net_id);
err = rpc_proc_init(net);
if (err)
goto err_proc;
err = ip_map_cache_create(net);
if (err)
goto err_ipmap;
err = unix_gid_cache_create(net);
if (err)
goto err_unixgid;
err = rpc_pipefs_init_net(net);
if (err)
goto err_pipefs;
INIT_LIST_HEAD(&sn->all_clients);
spin_lock_init(&sn->rpc_client_lock);
spin_lock_init(&sn->rpcb_clnt_lock);
return 0;
err_pipefs:
unix_gid_cache_destroy(net);
err_unixgid:
ip_map_cache_destroy(net);
err_ipmap:
rpc_proc_exit(net);
err_proc:
return err;
}
static __net_exit void sunrpc_exit_net(struct net *net)
{
rpc_pipefs_exit_net(net);
unix_gid_cache_destroy(net);
ip_map_cache_destroy(net);
rpc_proc_exit(net);
}
static struct pernet_operations sunrpc_net_ops = {
.init = sunrpc_init_net,
.exit = sunrpc_exit_net,
.id = &sunrpc_net_id,
.size = sizeof(struct sunrpc_net),
};
static int __init
init_sunrpc(void)
{
int err = rpc_init_mempool();
if (err)
goto out;
err = rpcauth_init_module();
if (err)
goto out2;
cache_initialize();
err = register_pernet_subsys(&sunrpc_net_ops);
if (err)
goto out3;
err = register_rpc_pipefs();
if (err)
goto out4;
sunrpc_debugfs_init();
#if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
rpc_register_sysctl();
#endif
svc_init_xprt_sock(); /* svc sock transport */
init_socket_xprt(); /* clnt sock transport */
return 0;
out4:
unregister_pernet_subsys(&sunrpc_net_ops);
out3:
rpcauth_remove_module();
out2:
rpc_destroy_mempool();
out:
return err;
}
static void __exit
cleanup_sunrpc(void)
{
rpcauth_remove_module();
cleanup_socket_xprt();
svc_cleanup_xprt_sock();
sunrpc_debugfs_exit();
unregister_rpc_pipefs();
rpc_destroy_mempool();
unregister_pernet_subsys(&sunrpc_net_ops);
#if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
rpc_unregister_sysctl();
#endif
rcu_barrier(); /* Wait for completion of call_rcu()'s */
}
MODULE_LICENSE("GPL");
fs_initcall(init_sunrpc); /* Ensure we're initialised before nfs */
module_exit(cleanup_sunrpc);