android_kernel_motorola_sm6225/fs/jfs/jfs_unicode.c
Sonny Rao f5f287738b JFS: performance patch
Basically, we saw a large amount of time spent in the
jfs_strfromUCS_le() function, mispredicting the branch inside the
loop, so I just added some unlikely modifiers to the if statements to
re-ordered the code.  Again, these simple changes provided > 2 % on
spec-sfs, so please consider it for inclusion.

Signed-off-by: Dave Kleikamp <shaggy@austin.ibm.com>
2005-06-23 16:57:56 -05:00

138 lines
3.3 KiB
C

/*
* Copyright (C) International Business Machines Corp., 2000-2004
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See
* the GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#include <linux/fs.h>
#include <linux/slab.h>
#include "jfs_incore.h"
#include "jfs_filsys.h"
#include "jfs_unicode.h"
#include "jfs_debug.h"
/*
* NAME: jfs_strfromUCS()
*
* FUNCTION: Convert little-endian unicode string to character string
*
*/
int jfs_strfromUCS_le(char *to, const __le16 * from,
int len, struct nls_table *codepage)
{
int i;
int outlen = 0;
static int warn_again = 5; /* Only warn up to 5 times total */
int warn = !!warn_again; /* once per string */
if (codepage) {
for (i = 0; (i < len) && from[i]; i++) {
int charlen;
charlen =
codepage->uni2char(le16_to_cpu(from[i]),
&to[outlen],
NLS_MAX_CHARSET_SIZE);
if (charlen > 0)
outlen += charlen;
else
to[outlen++] = '?';
}
} else {
for (i = 0; (i < len) && from[i]; i++) {
if (unlikely(le16_to_cpu(from[i]) & 0xff00)) {
to[i] = '?';
if (unlikely(warn)) {
warn--;
warn_again--;
printk(KERN_ERR
"non-latin1 character 0x%x found in JFS file name\n",
le16_to_cpu(from[i]));
printk(KERN_ERR
"mount with iocharset=utf8 to access\n");
}
}
else
to[i] = (char) (le16_to_cpu(from[i]));
}
outlen = i;
}
to[outlen] = 0;
return outlen;
}
/*
* NAME: jfs_strtoUCS()
*
* FUNCTION: Convert character string to unicode string
*
*/
static int jfs_strtoUCS(wchar_t * to, const unsigned char *from, int len,
struct nls_table *codepage)
{
int charlen;
int i;
if (codepage) {
for (i = 0; len && *from; i++, from += charlen, len -= charlen)
{
charlen = codepage->char2uni(from, len, &to[i]);
if (charlen < 1) {
jfs_err("jfs_strtoUCS: char2uni returned %d.",
charlen);
jfs_err("charset = %s, char = 0x%x",
codepage->charset, *from);
return charlen;
}
}
} else {
for (i = 0; (i < len) && from[i]; i++)
to[i] = (wchar_t) from[i];
}
to[i] = 0;
return i;
}
/*
* NAME: get_UCSname()
*
* FUNCTION: Allocate and translate to unicode string
*
*/
int get_UCSname(struct component_name * uniName, struct dentry *dentry)
{
struct nls_table *nls_tab = JFS_SBI(dentry->d_sb)->nls_tab;
int length = dentry->d_name.len;
if (length > JFS_NAME_MAX)
return -ENAMETOOLONG;
uniName->name =
kmalloc((length + 1) * sizeof(wchar_t), GFP_NOFS);
if (uniName->name == NULL)
return -ENOSPC;
uniName->namlen = jfs_strtoUCS(uniName->name, dentry->d_name.name,
length, nls_tab);
if (uniName->namlen < 0) {
kfree(uniName->name);
return uniName->namlen;
}
return 0;
}