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       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                 :          0 : 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                 :          0 :         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                 :            : };