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Use atomic op to get next xid. Initialize value with arc4random() 

at nfs init time instead system time based trickery intermingled
with the runtime code.

le bouef: kills last simple_lock from nfs
This commit is contained in:
pooka 2008-10-09 00:11:39 +00:00
parent fb58d5d6ec
commit ae509fabab
1 changed files with 10 additions and 25 deletions
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35
sys/nfs/nfs_subs.c
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@ -1,4 +1,4 @@
/* $NetBSD: nfs_subs.c,v 1.206 2008/09/30 14:29:39 pooka Exp $ */
/* $NetBSD: nfs_subs.c,v 1.207 2008/10/09 00:11:39 pooka Exp $ */
/*
* Copyright (c) 1989, 1993
@ -70,7 +70,7 @@
*/
#include <sys/cdefs.h>
__KERNEL_RCSID(0, "$NetBSD: nfs_subs.c,v 1.206 2008/09/30 14:29:39 pooka Exp $");
__KERNEL_RCSID(0, "$NetBSD: nfs_subs.c,v 1.207 2008/10/09 00:11:39 pooka Exp $");
#include "fs_nfs.h"
#include "opt_nfs.h"
@ -99,6 +99,7 @@ __KERNEL_RCSID(0, "$NetBSD: nfs_subs.c,v 1.206 2008/09/30 14:29:39 pooka Exp $")
#include <sys/dirent.h>
#include <sys/once.h>
#include <sys/kauth.h>
#include <sys/atomic.h>
#include <uvm/uvm_extern.h>
@ -119,6 +120,8 @@ __KERNEL_RCSID(0, "$NetBSD: nfs_subs.c,v 1.206 2008/09/30 14:29:39 pooka Exp $")
#include <netiso/iso.h>
#endif
static u_int32_t nfs_xid;
/*
* Data items converted to xdr at startup, since they are constant
* This is kinda hokey, but may save a little time doing byte swaps
@ -1539,6 +1542,7 @@ nfs_init0(void)
nfs_ticks = (hz * NFS_TICKINTVL + 500) / 1000;
if (nfs_ticks < 1)
nfs_ticks = 1;
nfs_xid = arc4random();
#ifdef NFSSERVER
vfs_hooks_attach(&nfs_export_hooks);
nfsrv_init(0); /* Init server data structures */
@ -2909,31 +2913,12 @@ nfsrv_errmap(nd, err)
u_int32_t
nfs_getxid()
{
static u_int32_t base;
static u_int32_t nfs_xid = 0;
static struct simplelock nfs_xidlock = SIMPLELOCK_INITIALIZER;
u_int32_t newxid;
simple_lock(&nfs_xidlock);
/*
* derive initial xid from system time
* XXX time is invalid if root not yet mounted
*/
if (__predict_false(!base && (rootvp))) {
struct timeval tv;
microtime(&tv);
base = tv.tv_sec << 12;
nfs_xid = base;
}
/*
* Skip zero xid if it should ever happen.
*/
if (__predict_false(++nfs_xid == 0))
nfs_xid++;
newxid = nfs_xid;
simple_unlock(&nfs_xidlock);
/* get next xid. skip 0 */
do {
newxid = atomic_inc_32_nv(&nfs_xid);
} while (__predict_false(newxid == 0));
return txdr_unsigned(newxid);
}