linux/fs/squashfs/xz_wrapper.c
Kirill A. Shutemov 09cbfeaf1a mm, fs: get rid of PAGE_CACHE_* and page_cache_{get,release} macros
PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} macros were introduced *long* time
ago with promise that one day it will be possible to implement page
cache with bigger chunks than PAGE_SIZE.

This promise never materialized.  And unlikely will.

We have many places where PAGE_CACHE_SIZE assumed to be equal to
PAGE_SIZE.  And it's constant source of confusion on whether
PAGE_CACHE_* or PAGE_* constant should be used in a particular case,
especially on the border between fs and mm.

Global switching to PAGE_CACHE_SIZE != PAGE_SIZE would cause to much
breakage to be doable.

Let's stop pretending that pages in page cache are special.  They are
not.

The changes are pretty straight-forward:

 - <foo> << (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>;

 - <foo> >> (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>;

 - PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} -> PAGE_{SIZE,SHIFT,MASK,ALIGN};

 - page_cache_get() -> get_page();

 - page_cache_release() -> put_page();

This patch contains automated changes generated with coccinelle using
script below.  For some reason, coccinelle doesn't patch header files.
I've called spatch for them manually.

The only adjustment after coccinelle is revert of changes to
PAGE_CAHCE_ALIGN definition: we are going to drop it later.

There are few places in the code where coccinelle didn't reach.  I'll
fix them manually in a separate patch.  Comments and documentation also
will be addressed with the separate patch.

virtual patch

@@
expression E;
@@
- E << (PAGE_CACHE_SHIFT - PAGE_SHIFT)
+ E

@@
expression E;
@@
- E >> (PAGE_CACHE_SHIFT - PAGE_SHIFT)
+ E

@@
@@
- PAGE_CACHE_SHIFT
+ PAGE_SHIFT

@@
@@
- PAGE_CACHE_SIZE
+ PAGE_SIZE

@@
@@
- PAGE_CACHE_MASK
+ PAGE_MASK

@@
expression E;
@@
- PAGE_CACHE_ALIGN(E)
+ PAGE_ALIGN(E)

@@
expression E;
@@
- page_cache_get(E)
+ get_page(E)

@@
expression E;
@@
- page_cache_release(E)
+ put_page(E)

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2016-04-04 10:41:08 -07:00

194 lines
4.3 KiB
C

/*
* Squashfs - a compressed read only filesystem for Linux
*
* Copyright (c) 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009, 2010
* Phillip Lougher <phillip@squashfs.org.uk>
*
* 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,
* 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, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
*
* xz_wrapper.c
*/
#include <linux/mutex.h>
#include <linux/buffer_head.h>
#include <linux/slab.h>
#include <linux/xz.h>
#include <linux/bitops.h>
#include "squashfs_fs.h"
#include "squashfs_fs_sb.h"
#include "squashfs.h"
#include "decompressor.h"
#include "page_actor.h"
struct squashfs_xz {
struct xz_dec *state;
struct xz_buf buf;
};
struct disk_comp_opts {
__le32 dictionary_size;
__le32 flags;
};
struct comp_opts {
int dict_size;
};
static void *squashfs_xz_comp_opts(struct squashfs_sb_info *msblk,
void *buff, int len)
{
struct disk_comp_opts *comp_opts = buff;
struct comp_opts *opts;
int err = 0, n;
opts = kmalloc(sizeof(*opts), GFP_KERNEL);
if (opts == NULL) {
err = -ENOMEM;
goto out2;
}
if (comp_opts) {
/* check compressor options are the expected length */
if (len < sizeof(*comp_opts)) {
err = -EIO;
goto out;
}
opts->dict_size = le32_to_cpu(comp_opts->dictionary_size);
/* the dictionary size should be 2^n or 2^n+2^(n+1) */
n = ffs(opts->dict_size) - 1;
if (opts->dict_size != (1 << n) && opts->dict_size != (1 << n) +
(1 << (n + 1))) {
err = -EIO;
goto out;
}
} else
/* use defaults */
opts->dict_size = max_t(int, msblk->block_size,
SQUASHFS_METADATA_SIZE);
return opts;
out:
kfree(opts);
out2:
return ERR_PTR(err);
}
static void *squashfs_xz_init(struct squashfs_sb_info *msblk, void *buff)
{
struct comp_opts *comp_opts = buff;
struct squashfs_xz *stream;
int err;
stream = kmalloc(sizeof(*stream), GFP_KERNEL);
if (stream == NULL) {
err = -ENOMEM;
goto failed;
}
stream->state = xz_dec_init(XZ_PREALLOC, comp_opts->dict_size);
if (stream->state == NULL) {
kfree(stream);
err = -ENOMEM;
goto failed;
}
return stream;
failed:
ERROR("Failed to initialise xz decompressor\n");
return ERR_PTR(err);
}
static void squashfs_xz_free(void *strm)
{
struct squashfs_xz *stream = strm;
if (stream) {
xz_dec_end(stream->state);
kfree(stream);
}
}
static int squashfs_xz_uncompress(struct squashfs_sb_info *msblk, void *strm,
struct buffer_head **bh, int b, int offset, int length,
struct squashfs_page_actor *output)
{
enum xz_ret xz_err;
int avail, total = 0, k = 0;
struct squashfs_xz *stream = strm;
xz_dec_reset(stream->state);
stream->buf.in_pos = 0;
stream->buf.in_size = 0;
stream->buf.out_pos = 0;
stream->buf.out_size = PAGE_SIZE;
stream->buf.out = squashfs_first_page(output);
do {
if (stream->buf.in_pos == stream->buf.in_size && k < b) {
avail = min(length, msblk->devblksize - offset);
length -= avail;
stream->buf.in = bh[k]->b_data + offset;
stream->buf.in_size = avail;
stream->buf.in_pos = 0;
offset = 0;
}
if (stream->buf.out_pos == stream->buf.out_size) {
stream->buf.out = squashfs_next_page(output);
if (stream->buf.out != NULL) {
stream->buf.out_pos = 0;
total += PAGE_SIZE;
}
}
xz_err = xz_dec_run(stream->state, &stream->buf);
if (stream->buf.in_pos == stream->buf.in_size && k < b)
put_bh(bh[k++]);
} while (xz_err == XZ_OK);
squashfs_finish_page(output);
if (xz_err != XZ_STREAM_END || k < b)
goto out;
return total + stream->buf.out_pos;
out:
for (; k < b; k++)
put_bh(bh[k]);
return -EIO;
}
const struct squashfs_decompressor squashfs_xz_comp_ops = {
.init = squashfs_xz_init,
.comp_opts = squashfs_xz_comp_opts,
.free = squashfs_xz_free,
.decompress = squashfs_xz_uncompress,
.id = XZ_COMPRESSION,
.name = "xz",
.supported = 1
};