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 
ramfs_mmu_get_unmapped_area(struct file * file,unsigned long addr,unsigned long len,unsigned long pgoff,unsigned long flags)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	= generic_file_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