[PATCH] v4l: bug fixes for tuner, cx88 and tea5767
[linux-3.10.git] / fs / ext2 / xip.c
1 /*
2  *  linux/fs/ext2/xip.c
3  *
4  * Copyright (C) 2005 IBM Corporation
5  * Author: Carsten Otte (cotte@de.ibm.com)
6  */
7
8 #include <linux/mm.h>
9 #include <linux/fs.h>
10 #include <linux/genhd.h>
11 #include <linux/buffer_head.h>
12 #include <linux/ext2_fs_sb.h>
13 #include <linux/ext2_fs.h>
14 #include "ext2.h"
15 #include "xip.h"
16
17 static inline int
18 __inode_direct_access(struct inode *inode, sector_t sector, unsigned long *data) {
19         BUG_ON(!inode->i_sb->s_bdev->bd_disk->fops->direct_access);
20         return inode->i_sb->s_bdev->bd_disk->fops
21                 ->direct_access(inode->i_sb->s_bdev,sector,data);
22 }
23
24 int
25 ext2_clear_xip_target(struct inode *inode, int block) {
26         sector_t sector = block*(PAGE_SIZE/512);
27         unsigned long data;
28         int rc;
29
30         rc = __inode_direct_access(inode, sector, &data);
31         if (rc)
32                 return rc;
33         clear_page((void*)data);
34         return 0;
35 }
36
37 void ext2_xip_verify_sb(struct super_block *sb)
38 {
39         struct ext2_sb_info *sbi = EXT2_SB(sb);
40
41         if ((sbi->s_mount_opt & EXT2_MOUNT_XIP)) {
42                 if ((sb->s_bdev == NULL) ||
43                         sb->s_bdev->bd_disk == NULL ||
44                         sb->s_bdev->bd_disk->fops == NULL ||
45                         sb->s_bdev->bd_disk->fops->direct_access == NULL) {
46                         sbi->s_mount_opt &= (~EXT2_MOUNT_XIP);
47                         ext2_warning(sb, __FUNCTION__,
48                                 "ignoring xip option - not supported by bdev");
49                 }
50         }
51 }
52
53 struct page*
54 ext2_get_xip_page(struct address_space *mapping, sector_t blockno,
55                    int create)
56 {
57         int rc;
58         unsigned long data;
59         struct buffer_head tmp;
60
61         tmp.b_state = 0;
62         tmp.b_blocknr = 0;
63         rc = ext2_get_block(mapping->host, blockno/(PAGE_SIZE/512) , &tmp,
64                                 create);
65         if (rc)
66                 return ERR_PTR(rc);
67         if (tmp.b_blocknr == 0) {
68                 /* SPARSE block */
69                 BUG_ON(create);
70                 return ERR_PTR(-ENODATA);
71         }
72
73         rc = __inode_direct_access
74                 (mapping->host,tmp.b_blocknr*(PAGE_SIZE/512) ,&data);
75         if (rc)
76                 return ERR_PTR(rc);
77
78         SetPageUptodate(virt_to_page(data));
79         return virt_to_page(data);
80 }