1 | /* file-mmu.c: ramfs MMU-based file operations |
2 | * |
3 | * Resizable simple ram filesystem for Linux. |
4 | * |
5 | * Copyright (C) 2000 Linus Torvalds. |
6 | * 2000 Transmeta Corp. |
7 | * |
8 | * Usage limits added by David Gibson, Linuxcare Australia. |
9 | * This file is released under the GPL. |
10 | */ |
11 | |
12 | /* |
13 | * NOTE! This filesystem is probably most useful |
14 | * not as a real filesystem, but as an example of |
15 | * how virtual filesystems can be written. |
16 | * |
17 | * It doesn't get much simpler than this. Consider |
18 | * that this file implements the full semantics of |
19 | * a POSIX-compliant read-write filesystem. |
20 | * |
21 | * Note in particular how the filesystem does not |
22 | * need to implement any data structures of its own |
23 | * to keep track of the virtual data: using the VFS |
24 | * caches is sufficient. |
25 | */ |
26 | |
27 | #include <linux/fs.h> |
28 | #include <linux/mm.h> |
29 | #include <linux/ramfs.h> |
30 | #include <linux/sched.h> |
31 | |
32 | #include "internal.h" |
33 | |
34 | static unsigned long ramfs_mmu_get_unmapped_area(struct file *file, |
35 | unsigned long addr, unsigned long len, unsigned long pgoff, |
36 | unsigned long flags) |
37 | { |
38 | return current->mm->get_unmapped_area(file, addr, len, pgoff, flags); |
39 | } |
40 | |
41 | const struct file_operations ramfs_file_operations = { |
42 | .read_iter = generic_file_read_iter, |
43 | .write_iter = generic_file_write_iter, |
44 | .mmap = generic_file_mmap, |
45 | .fsync = noop_fsync, |
46 | .splice_read = filemap_splice_read, |
47 | .splice_write = iter_file_splice_write, |
48 | .llseek = generic_file_llseek, |
49 | .get_unmapped_area = ramfs_mmu_get_unmapped_area, |
50 | }; |
51 | |
52 | const struct inode_operations ramfs_file_inode_operations = { |
53 | .setattr = simple_setattr, |
54 | .getattr = simple_getattr, |
55 | }; |
56 | |