video: tegra: dc: Add quick for Vizio P series
[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/blkdev.h>
13 #include "ext2.h"
14 #include "xip.h"
15
16 static inline int
17 __inode_direct_access(struct inode *inode, sector_t block,
18                       void **kaddr, unsigned long *pfn)
19 {
20         struct block_device *bdev = inode->i_sb->s_bdev;
21         const struct block_device_operations *ops = bdev->bd_disk->fops;
22         sector_t sector;
23
24         sector = block * (PAGE_SIZE / 512); /* ext2 block to bdev sector */
25
26         BUG_ON(!ops->direct_access);
27         return ops->direct_access(bdev, sector, kaddr, pfn);
28 }
29
30 static inline int
31 __ext2_get_block(struct inode *inode, pgoff_t pgoff, int create,
32                    sector_t *result)
33 {
34         struct buffer_head tmp;
35         int rc;
36
37         memset(&tmp, 0, sizeof(struct buffer_head));
38         tmp.b_size = 1 << inode->i_blkbits;
39         rc = ext2_get_block(inode, pgoff, &tmp, create);
40         *result = tmp.b_blocknr;
41
42         /* did we get a sparse block (hole in the file)? */
43         if (!tmp.b_blocknr && !rc) {
44                 BUG_ON(create);
45                 rc = -ENODATA;
46         }
47
48         return rc;
49 }
50
51 int
52 ext2_clear_xip_target(struct inode *inode, sector_t block)
53 {
54         void *kaddr;
55         unsigned long pfn;
56         int rc;
57
58         rc = __inode_direct_access(inode, block, &kaddr, &pfn);
59         if (!rc)
60                 clear_page(kaddr);
61         return rc;
62 }
63
64 void ext2_xip_verify_sb(struct super_block *sb)
65 {
66         struct ext2_sb_info *sbi = EXT2_SB(sb);
67
68         if ((sbi->s_mount_opt & EXT2_MOUNT_XIP) &&
69             !sb->s_bdev->bd_disk->fops->direct_access) {
70                 sbi->s_mount_opt &= (~EXT2_MOUNT_XIP);
71                 ext2_msg(sb, KERN_WARNING,
72                              "warning: ignoring xip option - "
73                              "not supported by bdev");
74         }
75 }
76
77 int ext2_get_xip_mem(struct address_space *mapping, pgoff_t pgoff, int create,
78                                 void **kmem, unsigned long *pfn)
79 {
80         int rc;
81         sector_t block;
82
83         /* first, retrieve the sector number */
84         rc = __ext2_get_block(mapping->host, pgoff, create, &block);
85         if (rc)
86                 return rc;
87
88         /* retrieve address of the target data */
89         rc = __inode_direct_access(mapping->host, block, kmem, pfn);
90         return rc;
91 }