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dd22f551ac
In order to support accesses to larger chunks of memory, pass in a 'size' parameter (counted in bytes), and return the amount available at that address. Add a new helper function, bdev_direct_access(), to handle common functionality including partition handling, checking the length requested is positive, checking for the sector being page-aligned, and checking the length of the request does not pass the end of the partition. Signed-off-by: Matthew Wilcox <matthew.r.wilcox@intel.com> Reviewed-by: Jan Kara <jack@suse.cz> Reviewed-by: Boaz Harrosh <boaz@plexistor.com> Signed-off-by: Jens Axboe <axboe@fb.com>
87 lines
2 KiB
C
87 lines
2 KiB
C
/*
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* linux/fs/ext2/xip.c
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*
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* Copyright (C) 2005 IBM Corporation
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* Author: Carsten Otte (cotte@de.ibm.com)
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*/
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#include <linux/mm.h>
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#include <linux/fs.h>
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#include <linux/genhd.h>
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#include <linux/buffer_head.h>
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#include <linux/blkdev.h>
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#include "ext2.h"
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#include "xip.h"
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static inline long __inode_direct_access(struct inode *inode, sector_t block,
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void **kaddr, unsigned long *pfn, long size)
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{
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struct block_device *bdev = inode->i_sb->s_bdev;
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sector_t sector = block * (PAGE_SIZE / 512);
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return bdev_direct_access(bdev, sector, kaddr, pfn, size);
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}
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static inline int
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__ext2_get_block(struct inode *inode, pgoff_t pgoff, int create,
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sector_t *result)
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{
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struct buffer_head tmp;
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int rc;
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memset(&tmp, 0, sizeof(struct buffer_head));
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tmp.b_size = 1 << inode->i_blkbits;
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rc = ext2_get_block(inode, pgoff, &tmp, create);
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*result = tmp.b_blocknr;
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/* did we get a sparse block (hole in the file)? */
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if (!tmp.b_blocknr && !rc) {
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BUG_ON(create);
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rc = -ENODATA;
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}
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return rc;
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}
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int
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ext2_clear_xip_target(struct inode *inode, sector_t block)
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{
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void *kaddr;
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unsigned long pfn;
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long size;
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size = __inode_direct_access(inode, block, &kaddr, &pfn, PAGE_SIZE);
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if (size < 0)
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return size;
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clear_page(kaddr);
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return 0;
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}
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void ext2_xip_verify_sb(struct super_block *sb)
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{
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struct ext2_sb_info *sbi = EXT2_SB(sb);
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if ((sbi->s_mount_opt & EXT2_MOUNT_XIP) &&
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!sb->s_bdev->bd_disk->fops->direct_access) {
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sbi->s_mount_opt &= (~EXT2_MOUNT_XIP);
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ext2_msg(sb, KERN_WARNING,
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"warning: ignoring xip option - "
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"not supported by bdev");
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}
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}
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int ext2_get_xip_mem(struct address_space *mapping, pgoff_t pgoff, int create,
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void **kmem, unsigned long *pfn)
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{
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long rc;
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sector_t block;
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/* first, retrieve the sector number */
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rc = __ext2_get_block(mapping->host, pgoff, create, &block);
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if (rc)
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return rc;
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/* retrieve address of the target data */
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rc = __inode_direct_access(mapping->host, block, kmem, pfn, PAGE_SIZE);
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return (rc < 0) ? rc : 0;
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}
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