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![Kirill A. Shutemov](/assets/img/avatar_default.png)
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>
148 lines
3.7 KiB
C
148 lines
3.7 KiB
C
/*
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* Squashfs - a compressed read only filesystem for Linux
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*
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* Copyright (c) 2002, 2003, 2004, 2005, 2006, 2007, 2008, 2009
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* Phillip Lougher <phillip@squashfs.org.uk>
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version 2,
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* or (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
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*
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* decompressor.c
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*/
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#include <linux/types.h>
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#include <linux/mutex.h>
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#include <linux/slab.h>
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#include <linux/buffer_head.h>
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#include "squashfs_fs.h"
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#include "squashfs_fs_sb.h"
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#include "decompressor.h"
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#include "squashfs.h"
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#include "page_actor.h"
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/*
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* This file (and decompressor.h) implements a decompressor framework for
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* Squashfs, allowing multiple decompressors to be easily supported
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*/
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static const struct squashfs_decompressor squashfs_lzma_unsupported_comp_ops = {
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NULL, NULL, NULL, NULL, LZMA_COMPRESSION, "lzma", 0
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};
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#ifndef CONFIG_SQUASHFS_LZ4
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static const struct squashfs_decompressor squashfs_lz4_comp_ops = {
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NULL, NULL, NULL, NULL, LZ4_COMPRESSION, "lz4", 0
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};
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#endif
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#ifndef CONFIG_SQUASHFS_LZO
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static const struct squashfs_decompressor squashfs_lzo_comp_ops = {
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NULL, NULL, NULL, NULL, LZO_COMPRESSION, "lzo", 0
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};
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#endif
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#ifndef CONFIG_SQUASHFS_XZ
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static const struct squashfs_decompressor squashfs_xz_comp_ops = {
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NULL, NULL, NULL, NULL, XZ_COMPRESSION, "xz", 0
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};
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#endif
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#ifndef CONFIG_SQUASHFS_ZLIB
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static const struct squashfs_decompressor squashfs_zlib_comp_ops = {
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NULL, NULL, NULL, NULL, ZLIB_COMPRESSION, "zlib", 0
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};
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#endif
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static const struct squashfs_decompressor squashfs_unknown_comp_ops = {
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NULL, NULL, NULL, NULL, 0, "unknown", 0
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};
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static const struct squashfs_decompressor *decompressor[] = {
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&squashfs_zlib_comp_ops,
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&squashfs_lz4_comp_ops,
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&squashfs_lzo_comp_ops,
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&squashfs_xz_comp_ops,
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&squashfs_lzma_unsupported_comp_ops,
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&squashfs_unknown_comp_ops
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};
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const struct squashfs_decompressor *squashfs_lookup_decompressor(int id)
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{
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int i;
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for (i = 0; decompressor[i]->id; i++)
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if (id == decompressor[i]->id)
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break;
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return decompressor[i];
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}
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static void *get_comp_opts(struct super_block *sb, unsigned short flags)
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{
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struct squashfs_sb_info *msblk = sb->s_fs_info;
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void *buffer = NULL, *comp_opts;
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struct squashfs_page_actor *actor = NULL;
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int length = 0;
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/*
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* Read decompressor specific options from file system if present
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*/
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if (SQUASHFS_COMP_OPTS(flags)) {
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buffer = kmalloc(PAGE_SIZE, GFP_KERNEL);
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if (buffer == NULL) {
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comp_opts = ERR_PTR(-ENOMEM);
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goto out;
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}
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actor = squashfs_page_actor_init(&buffer, 1, 0);
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if (actor == NULL) {
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comp_opts = ERR_PTR(-ENOMEM);
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goto out;
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}
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length = squashfs_read_data(sb,
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sizeof(struct squashfs_super_block), 0, NULL, actor);
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if (length < 0) {
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comp_opts = ERR_PTR(length);
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goto out;
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}
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}
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comp_opts = squashfs_comp_opts(msblk, buffer, length);
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out:
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kfree(actor);
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kfree(buffer);
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return comp_opts;
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}
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void *squashfs_decompressor_setup(struct super_block *sb, unsigned short flags)
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{
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struct squashfs_sb_info *msblk = sb->s_fs_info;
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void *stream, *comp_opts = get_comp_opts(sb, flags);
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if (IS_ERR(comp_opts))
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return comp_opts;
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stream = squashfs_decompressor_create(msblk, comp_opts);
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if (IS_ERR(stream))
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kfree(comp_opts);
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return stream;
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}
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