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1/* file-mmu.c: ramfs MMU-based file operations2 *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 useful14 * not as a real filesystem, but as an example of15 * how virtual filesystems can be written.16 *17 * It doesn't get much simpler than this. Consider18 * that this file implements the full semantics of19 * a POSIX-compliant read-write filesystem.20 *21 * Note in particular how the filesystem does not22 * need to implement any data structures of its own23 * to keep track of the virtual data: using the VFS24 * 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 34static 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 mm_get_unmapped_area(current->mm, file, addr, len, pgoff, flags);39}40 41const 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 52const struct inode_operations ramfs_file_inode_operations = {53 .setattr = simple_setattr,54 .getattr = simple_getattr,55};56