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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>
183 lines
4.5 KiB
C
183 lines
4.5 KiB
C
/*
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* Copyright (c) 2000-2001 Christoph Hellwig.
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* All rights reserved.
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions, and the following disclaimer,
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* without modification.
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* 2. The name of the author may not be used to endorse or promote products
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* derived from this software without specific prior written permission.
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*
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* Alternatively, this software may be distributed under the terms of the
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* GNU General Public License ("GPL").
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
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* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
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* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE FOR
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* ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
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* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
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* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
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* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
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* SUCH DAMAGE.
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*/
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/*
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* Veritas filesystem driver - shared subroutines.
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*/
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#include <linux/fs.h>
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#include <linux/buffer_head.h>
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#include <linux/kernel.h>
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#include <linux/pagemap.h>
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#include "vxfs_extern.h"
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static int vxfs_readpage(struct file *, struct page *);
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static sector_t vxfs_bmap(struct address_space *, sector_t);
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const struct address_space_operations vxfs_aops = {
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.readpage = vxfs_readpage,
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.bmap = vxfs_bmap,
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};
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inline void
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vxfs_put_page(struct page *pp)
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{
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kunmap(pp);
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put_page(pp);
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}
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/**
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* vxfs_get_page - read a page into memory.
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* @ip: inode to read from
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* @n: page number
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*
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* Description:
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* vxfs_get_page reads the @n th page of @ip into the pagecache.
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*
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* Returns:
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* The wanted page on success, else a NULL pointer.
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*/
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struct page *
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vxfs_get_page(struct address_space *mapping, u_long n)
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{
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struct page * pp;
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pp = read_mapping_page(mapping, n, NULL);
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if (!IS_ERR(pp)) {
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kmap(pp);
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/** if (!PageChecked(pp)) **/
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/** vxfs_check_page(pp); **/
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if (PageError(pp))
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goto fail;
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}
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return (pp);
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fail:
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vxfs_put_page(pp);
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return ERR_PTR(-EIO);
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}
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/**
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* vxfs_bread - read buffer for a give inode,block tuple
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* @ip: inode
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* @block: logical block
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*
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* Description:
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* The vxfs_bread function reads block no @block of
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* @ip into the buffercache.
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*
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* Returns:
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* The resulting &struct buffer_head.
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*/
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struct buffer_head *
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vxfs_bread(struct inode *ip, int block)
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{
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struct buffer_head *bp;
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daddr_t pblock;
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pblock = vxfs_bmap1(ip, block);
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bp = sb_bread(ip->i_sb, pblock);
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return (bp);
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}
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/**
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* vxfs_get_block - locate buffer for given inode,block tuple
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* @ip: inode
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* @iblock: logical block
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* @bp: buffer skeleton
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* @create: %TRUE if blocks may be newly allocated.
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*
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* Description:
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* The vxfs_get_block function fills @bp with the right physical
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* block and device number to perform a lowlevel read/write on
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* it.
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*
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* Returns:
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* Zero on success, else a negativ error code (-EIO).
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*/
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static int
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vxfs_getblk(struct inode *ip, sector_t iblock,
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struct buffer_head *bp, int create)
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{
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daddr_t pblock;
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pblock = vxfs_bmap1(ip, iblock);
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if (pblock != 0) {
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map_bh(bp, ip->i_sb, pblock);
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return 0;
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}
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return -EIO;
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}
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/**
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* vxfs_readpage - read one page synchronously into the pagecache
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* @file: file context (unused)
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* @page: page frame to fill in.
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*
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* Description:
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* The vxfs_readpage routine reads @page synchronously into the
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* pagecache.
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*
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* Returns:
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* Zero on success, else a negative error code.
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*
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* Locking status:
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* @page is locked and will be unlocked.
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*/
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static int
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vxfs_readpage(struct file *file, struct page *page)
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{
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return block_read_full_page(page, vxfs_getblk);
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}
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/**
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* vxfs_bmap - perform logical to physical block mapping
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* @mapping: logical to physical mapping to use
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* @block: logical block (relative to @mapping).
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*
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* Description:
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* Vxfs_bmap find out the corresponding phsical block to the
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* @mapping, @block pair.
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*
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* Returns:
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* Physical block number on success, else Zero.
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*
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* Locking status:
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* We are under the bkl.
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*/
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static sector_t
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vxfs_bmap(struct address_space *mapping, sector_t block)
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{
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return generic_block_bmap(mapping, block, vxfs_getblk);
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}
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