/* * linux/fs/ext2/xip.c * * Copyright (C) 2005 IBM Corporation * Author: Carsten Otte (cotte@de.ibm.com) */ #include <linux/mm.h> #include <linux/fs.h> #include <linux/genhd.h> #include <linux/buffer_head.h> #include <linux/ext2_fs_sb.h> #include <linux/ext2_fs.h> #include <linux/blkdev.h> #include "ext2.h" #include "xip.h" static inline int __inode_direct_access(struct inode *inode, sector_t block, void **kaddr, unsigned long *pfn) { struct block_device *bdev = inode->i_sb->s_bdev; const struct block_device_operations *ops = bdev->bd_disk->fops; sector_t sector; sector = block * (PAGE_SIZE / 512); /* ext2 block to bdev sector */ BUG_ON(!ops->direct_access); return ops->direct_access(bdev, sector, kaddr, pfn); } static inline int __ext2_get_block(struct inode *inode, pgoff_t pgoff, int create, sector_t *result) { struct buffer_head tmp; int rc; memset(&tmp, 0, sizeof(struct buffer_head)); rc = ext2_get_block(inode, pgoff, &tmp, create); *result = tmp.b_blocknr; /* did we get a sparse block (hole in the file)? */ if (!tmp.b_blocknr && !rc) { BUG_ON(create); rc = -ENODATA; } return rc; } int ext2_clear_xip_target(struct inode *inode, sector_t block) { void *kaddr; unsigned long pfn; int rc; rc = __inode_direct_access(inode, block, &kaddr, &pfn); if (!rc) clear_page(kaddr); return rc; } void ext2_xip_verify_sb(struct super_block *sb) { struct ext2_sb_info *sbi = EXT2_SB(sb); if ((sbi->s_mount_opt & EXT2_MOUNT_XIP) && !sb->s_bdev->bd_disk->fops->direct_access) { sbi->s_mount_opt &= (~EXT2_MOUNT_XIP); ext2_warning(sb, __func__, "ignoring xip option - not supported by bdev"); } } int ext2_get_xip_mem(struct address_space *mapping, pgoff_t pgoff, int create, void **kmem, unsigned long *pfn) { int rc; sector_t block; /* first, retrieve the sector number */ rc = __ext2_get_block(mapping->host, pgoff, create, &block); if (rc) return rc; /* retrieve address of the target data */ rc = __inode_direct_access(mapping->host, block, kmem, pfn); return rc; }